src/src/expand.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2016 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8
   9 /* Functions for handling string expansion. */
  10
  11
  12 #include "exim.h"
  13
  14 /* Recursively called function */
  15
  16 static uschar *expand_string_internal(const uschar *, BOOL, const uschar **, BOOL, BOOL, BOOL *);
  17 static int_eximarith_t expanded_string_integer(const uschar *, BOOL);
  18
  19 #ifdef STAND_ALONE
  20 #ifndef SUPPORT_CRYPTEQ
  21 #define SUPPORT_CRYPTEQ
  22 #endif
  23 #endif
  24
  25 #ifdef LOOKUP_LDAP
  26 #include "lookups/ldap.h"
  27 #endif
  28
  29 #ifdef SUPPORT_CRYPTEQ
  30 #ifdef CRYPT_H
  31 #include <crypt.h>
  32 #endif
  33 #ifndef HAVE_CRYPT16
  34 extern char* crypt16(char*, char*);
  35 #endif
  36 #endif
  37
  38 /* The handling of crypt16() is a mess. I will record below the analysis of the
  39 mess that was sent to me. We decided, however, to make changing this very low
  40 priority, because in practice people are moving away from the crypt()
  41 algorithms nowadays, so it doesn't seem worth it.
  42
  43 <quote>
  44 There is an algorithm named "crypt16" in Ultrix and Tru64.  It crypts
  45 the first 8 characters of the password using a 20-round version of crypt
  46 (standard crypt does 25 rounds).  It then crypts the next 8 characters,
  47 or an empty block if the password is less than 9 characters, using a
  48 20-round version of crypt and the same salt as was used for the first
  49 block.  Characters after the first 16 are ignored.  It always generates
  50 a 16-byte hash, which is expressed together with the salt as a string
  51 of 24 base 64 digits.  Here are some links to peruse:
  52
  53         http://cvs.pld.org.pl/pam/pamcrypt/crypt16.c?rev=1.2
  54         http://seclists.org/bugtraq/1999/Mar/0076.html
  55
  56 There's a different algorithm named "bigcrypt" in HP-UX, Digital Unix,
  57 and OSF/1.  This is the same as the standard crypt if given a password
  58 of 8 characters or less.  If given more, it first does the same as crypt
  59 using the first 8 characters, then crypts the next 8 (the 9th to 16th)
  60 using as salt the first two base 64 digits from the first hash block.
  61 If the password is more than 16 characters then it crypts the 17th to 24th
  62 characters using as salt the first two base 64 digits from the second hash
  63 block.  And so on: I've seen references to it cutting off the password at
  64 40 characters (5 blocks), 80 (10 blocks), or 128 (16 blocks).  Some links:
  65
  66         http://cvs.pld.org.pl/pam/pamcrypt/bigcrypt.c?rev=1.2
  67         http://seclists.org/bugtraq/1999/Mar/0109.html
  68         http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R2D-
  69              TET1_html/sec.c222.html#no_id_208
  70
  71 Exim has something it calls "crypt16".  It will either use a native
  72 crypt16 or its own implementation.  A native crypt16 will presumably
  73 be the one that I called "crypt16" above.  The internal "crypt16"
  74 function, however, is a two-block-maximum implementation of what I called
  75 "bigcrypt".  The documentation matches the internal code.
  76
  77 I suspect that whoever did the "crypt16" stuff for Exim didn't realise
  78 that crypt16 and bigcrypt were different things.
  79
  80 Exim uses the LDAP-style scheme identifier "{crypt16}" to refer
  81 to whatever it is using under that name.  This unfortunately sets a
  82 precedent for using "{crypt16}" to identify two incompatible algorithms
  83 whose output can't be distinguished.  With "{crypt16}" thus rendered
  84 ambiguous, I suggest you deprecate it and invent two new identifiers
  85 for the two algorithms.
  86
  87 Both crypt16 and bigcrypt are very poor algorithms, btw.  Hashing parts
  88 of the password separately means they can be cracked separately, so
  89 the double-length hash only doubles the cracking effort instead of
  90 squaring it.  I recommend salted SHA-1 ({SSHA}), or the Blowfish-based
  91 bcrypt ({CRYPT}$2a$).
  92 </quote>
  93 */
  94
  95
  96
  97 /*************************************************
  98 *            Local statics and tables            *
  99 *************************************************/
 100
 101 /* Table of item names, and corresponding switch numbers. The names must be in
 102 alphabetical order. */
 103
 104 static uschar *item_table[] = {
 105   US"acl",
 106   US"certextract",
 107   US"dlfunc",
 108   US"env",
 109   US"extract",
 110   US"filter",
 111   US"hash",
 112   US"hmac",
 113   US"if",
 114 #ifdef SUPPORT_I18N
 115   US"imapfolder",
 116 #endif
 117   US"length",
 118   US"listextract",
 119   US"lookup",
 120   US"map",
 121   US"nhash",
 122   US"perl",
 123   US"prvs",
 124   US"prvscheck",
 125   US"readfile",
 126   US"readsocket",
 127   US"reduce",
 128   US"run",
 129   US"sg",
 130   US"sort",
 131   US"substr",
 132   US"tr" };
 133
 134 enum {
 135   EITEM_ACL,
 136   EITEM_CERTEXTRACT,
 137   EITEM_DLFUNC,
 138   EITEM_ENV,
 139   EITEM_EXTRACT,
 140   EITEM_FILTER,
 141   EITEM_HASH,
 142   EITEM_HMAC,
 143   EITEM_IF,
 144 #ifdef SUPPORT_I18N
 145   EITEM_IMAPFOLDER,
 146 #endif
 147   EITEM_LENGTH,
 148   EITEM_LISTEXTRACT,
 149   EITEM_LOOKUP,
 150   EITEM_MAP,
 151   EITEM_NHASH,
 152   EITEM_PERL,
 153   EITEM_PRVS,
 154   EITEM_PRVSCHECK,
 155   EITEM_READFILE,
 156   EITEM_READSOCK,
 157   EITEM_REDUCE,
 158   EITEM_RUN,
 159   EITEM_SG,
 160   EITEM_SORT,
 161   EITEM_SUBSTR,
 162   EITEM_TR };
 163
 164 /* Tables of operator names, and corresponding switch numbers. The names must be
 165 in alphabetical order. There are two tables, because underscore is used in some
 166 cases to introduce arguments, whereas for other it is part of the name. This is
 167 an historical mis-design. */
 168
 169 static uschar *op_table_underscore[] = {
 170   US"from_utf8",
 171   US"local_part",
 172   US"quote_local_part",
 173   US"reverse_ip",
 174   US"time_eval",
 175   US"time_interval"
 176 #ifdef SUPPORT_I18N
 177  ,US"utf8_domain_from_alabel",
 178   US"utf8_domain_to_alabel",
 179   US"utf8_localpart_from_alabel",
 180   US"utf8_localpart_to_alabel"
 181 #endif
 182   };
 183
 184 enum {
 185   EOP_FROM_UTF8,
 186   EOP_LOCAL_PART,
 187   EOP_QUOTE_LOCAL_PART,
 188   EOP_REVERSE_IP,
 189   EOP_TIME_EVAL,
 190   EOP_TIME_INTERVAL
 191 #ifdef SUPPORT_I18N
 192  ,EOP_UTF8_DOMAIN_FROM_ALABEL,
 193   EOP_UTF8_DOMAIN_TO_ALABEL,
 194   EOP_UTF8_LOCALPART_FROM_ALABEL,
 195   EOP_UTF8_LOCALPART_TO_ALABEL
 196 #endif
 197   };
 198
 199 static uschar *op_table_main[] = {
 200   US"address",
 201   US"addresses",
 202   US"base32",
 203   US"base32d",
 204   US"base62",
 205   US"base62d",
 206   US"base64",
 207   US"base64d",
 208   US"domain",
 209   US"escape",
 210   US"escape8bit",
 211   US"eval",
 212   US"eval10",
 213   US"expand",
 214   US"h",
 215   US"hash",
 216   US"hex2b64",
 217   US"hexquote",
 218   US"ipv6denorm",
 219   US"ipv6norm",
 220   US"l",
 221   US"lc",
 222   US"length",
 223   US"listcount",
 224   US"listnamed",
 225   US"mask",
 226   US"md5",
 227   US"nh",
 228   US"nhash",
 229   US"quote",
 230   US"randint",
 231   US"rfc2047",
 232   US"rfc2047d",
 233   US"rxquote",
 234   US"s",
 235   US"sha1",
 236   US"sha256",
 237   US"sha3",
 238   US"stat",
 239   US"str2b64",
 240   US"strlen",
 241   US"substr",
 242   US"uc",
 243   US"utf8clean" };
 244
 245 enum {
 246   EOP_ADDRESS =  nelem(op_table_underscore),
 247   EOP_ADDRESSES,
 248   EOP_BASE32,
 249   EOP_BASE32D,
 250   EOP_BASE62,
 251   EOP_BASE62D,
 252   EOP_BASE64,
 253   EOP_BASE64D,
 254   EOP_DOMAIN,
 255   EOP_ESCAPE,
 256   EOP_ESCAPE8BIT,
 257   EOP_EVAL,
 258   EOP_EVAL10,
 259   EOP_EXPAND,
 260   EOP_H,
 261   EOP_HASH,
 262   EOP_HEX2B64,
 263   EOP_HEXQUOTE,
 264   EOP_IPV6DENORM,
 265   EOP_IPV6NORM,
 266   EOP_L,
 267   EOP_LC,
 268   EOP_LENGTH,
 269   EOP_LISTCOUNT,
 270   EOP_LISTNAMED,
 271   EOP_MASK,
 272   EOP_MD5,
 273   EOP_NH,
 274   EOP_NHASH,
 275   EOP_QUOTE,
 276   EOP_RANDINT,
 277   EOP_RFC2047,
 278   EOP_RFC2047D,
 279   EOP_RXQUOTE,
 280   EOP_S,
 281   EOP_SHA1,
 282   EOP_SHA256,
 283   EOP_SHA3,
 284   EOP_STAT,
 285   EOP_STR2B64,
 286   EOP_STRLEN,
 287   EOP_SUBSTR,
 288   EOP_UC,
 289   EOP_UTF8CLEAN };
 290
 291
 292 /* Table of condition names, and corresponding switch numbers. The names must
 293 be in alphabetical order. */
 294
 295 static uschar *cond_table[] = {
 296   US"<",
 297   US"<=",
 298   US"=",
 299   US"==",     /* Backward compatibility */
 300   US">",
 301   US">=",
 302   US"acl",
 303   US"and",
 304   US"bool",
 305   US"bool_lax",
 306   US"crypteq",
 307   US"def",
 308   US"eq",
 309   US"eqi",
 310   US"exists",
 311   US"first_delivery",
 312   US"forall",
 313   US"forany",
 314   US"ge",
 315   US"gei",
 316   US"gt",
 317   US"gti",
 318   US"inlist",
 319   US"inlisti",
 320   US"isip",
 321   US"isip4",
 322   US"isip6",
 323   US"ldapauth",
 324   US"le",
 325   US"lei",
 326   US"lt",
 327   US"lti",
 328   US"match",
 329   US"match_address",
 330   US"match_domain",
 331   US"match_ip",
 332   US"match_local_part",
 333   US"or",
 334   US"pam",
 335   US"pwcheck",
 336   US"queue_running",
 337   US"radius",
 338   US"saslauthd"
 339 };
 340
 341 enum {
 342   ECOND_NUM_L,
 343   ECOND_NUM_LE,
 344   ECOND_NUM_E,
 345   ECOND_NUM_EE,
 346   ECOND_NUM_G,
 347   ECOND_NUM_GE,
 348   ECOND_ACL,
 349   ECOND_AND,
 350   ECOND_BOOL,
 351   ECOND_BOOL_LAX,
 352   ECOND_CRYPTEQ,
 353   ECOND_DEF,
 354   ECOND_STR_EQ,
 355   ECOND_STR_EQI,
 356   ECOND_EXISTS,
 357   ECOND_FIRST_DELIVERY,
 358   ECOND_FORALL,
 359   ECOND_FORANY,
 360   ECOND_STR_GE,
 361   ECOND_STR_GEI,
 362   ECOND_STR_GT,
 363   ECOND_STR_GTI,
 364   ECOND_INLIST,
 365   ECOND_INLISTI,
 366   ECOND_ISIP,
 367   ECOND_ISIP4,
 368   ECOND_ISIP6,
 369   ECOND_LDAPAUTH,
 370   ECOND_STR_LE,
 371   ECOND_STR_LEI,
 372   ECOND_STR_LT,
 373   ECOND_STR_LTI,
 374   ECOND_MATCH,
 375   ECOND_MATCH_ADDRESS,
 376   ECOND_MATCH_DOMAIN,
 377   ECOND_MATCH_IP,
 378   ECOND_MATCH_LOCAL_PART,
 379   ECOND_OR,
 380   ECOND_PAM,
 381   ECOND_PWCHECK,
 382   ECOND_QUEUE_RUNNING,
 383   ECOND_RADIUS,
 384   ECOND_SASLAUTHD
 385 };
 386
 387
 388 /* Types of table entry */
 389
 390 enum vtypes {
 391   vtype_int,            /* value is address of int */
 392   vtype_filter_int,     /* ditto, but recognized only when filtering */
 393   vtype_ino,            /* value is address of ino_t (not always an int) */
 394   vtype_uid,            /* value is address of uid_t (not always an int) */
 395   vtype_gid,            /* value is address of gid_t (not always an int) */
 396   vtype_bool,           /* value is address of bool */
 397   vtype_stringptr,      /* value is address of pointer to string */
 398   vtype_msgbody,        /* as stringptr, but read when first required */
 399   vtype_msgbody_end,    /* ditto, the end of the message */
 400   vtype_msgheaders,     /* the message's headers, processed */
 401   vtype_msgheaders_raw, /* the message's headers, unprocessed */
 402   vtype_localpart,      /* extract local part from string */
 403   vtype_domain,         /* extract domain from string */
 404   vtype_string_func,    /* value is string returned by given function */
 405   vtype_todbsdin,       /* value not used; generate BSD inbox tod */
 406   vtype_tode,           /* value not used; generate tod in epoch format */
 407   vtype_todel,          /* value not used; generate tod in epoch/usec format */
 408   vtype_todf,           /* value not used; generate full tod */
 409   vtype_todl,           /* value not used; generate log tod */
 410   vtype_todlf,          /* value not used; generate log file datestamp tod */
 411   vtype_todzone,        /* value not used; generate time zone only */
 412   vtype_todzulu,        /* value not used; generate zulu tod */
 413   vtype_reply,          /* value not used; get reply from headers */
 414   vtype_pid,            /* value not used; result is pid */
 415   vtype_host_lookup,    /* value not used; get host name */
 416   vtype_load_avg,       /* value not used; result is int from os_getloadavg */
 417   vtype_pspace,         /* partition space; value is T/F for spool/log */
 418   vtype_pinodes,        /* partition inodes; value is T/F for spool/log */
 419   vtype_cert            /* SSL certificate */
 420   #ifndef DISABLE_DKIM
 421   ,vtype_dkim           /* Lookup of value in DKIM signature */
 422   #endif
 423 };
 424
 425 /* Type for main variable table */
 426
 427 typedef struct {
 428   const char *name;
 429   enum vtypes type;
 430   void       *value;
 431 } var_entry;
 432
 433 /* Type for entries pointing to address/length pairs. Not currently
 434 in use. */
 435
 436 typedef struct {
 437   uschar **address;
 438   int  *length;
 439 } alblock;
 440
 441 static uschar * fn_recipients(void);
 442
 443 /* This table must be kept in alphabetical order. */
 444
 445 static var_entry var_table[] = {
 446   /* WARNING: Do not invent variables whose names start acl_c or acl_m because
 447      they will be confused with user-creatable ACL variables. */
 448   { "acl_arg1",            vtype_stringptr,   &acl_arg[0] },
 449   { "acl_arg2",            vtype_stringptr,   &acl_arg[1] },
 450   { "acl_arg3",            vtype_stringptr,   &acl_arg[2] },
 451   { "acl_arg4",            vtype_stringptr,   &acl_arg[3] },
 452   { "acl_arg5",            vtype_stringptr,   &acl_arg[4] },
 453   { "acl_arg6",            vtype_stringptr,   &acl_arg[5] },
 454   { "acl_arg7",            vtype_stringptr,   &acl_arg[6] },
 455   { "acl_arg8",            vtype_stringptr,   &acl_arg[7] },
 456   { "acl_arg9",            vtype_stringptr,   &acl_arg[8] },
 457   { "acl_narg",            vtype_int,         &acl_narg },
 458   { "acl_verify_message",  vtype_stringptr,   &acl_verify_message },
 459   { "address_data",        vtype_stringptr,   &deliver_address_data },
 460   { "address_file",        vtype_stringptr,   &address_file },
 461   { "address_pipe",        vtype_stringptr,   &address_pipe },
 462   { "authenticated_fail_id",vtype_stringptr,  &authenticated_fail_id },
 463   { "authenticated_id",    vtype_stringptr,   &authenticated_id },
 464   { "authenticated_sender",vtype_stringptr,   &authenticated_sender },
 465   { "authentication_failed",vtype_int,        &authentication_failed },
 466 #ifdef WITH_CONTENT_SCAN
 467   { "av_failed",           vtype_int,         &av_failed },
 468 #endif
 469 #ifdef EXPERIMENTAL_BRIGHTMAIL
 470   { "bmi_alt_location",    vtype_stringptr,   &bmi_alt_location },
 471   { "bmi_base64_tracker_verdict", vtype_stringptr, &bmi_base64_tracker_verdict },
 472   { "bmi_base64_verdict",  vtype_stringptr,   &bmi_base64_verdict },
 473   { "bmi_deliver",         vtype_int,         &bmi_deliver },
 474 #endif
 475   { "body_linecount",      vtype_int,         &body_linecount },
 476   { "body_zerocount",      vtype_int,         &body_zerocount },
 477   { "bounce_recipient",    vtype_stringptr,   &bounce_recipient },
 478   { "bounce_return_size_limit", vtype_int,    &bounce_return_size_limit },
 479   { "caller_gid",          vtype_gid,         &real_gid },
 480   { "caller_uid",          vtype_uid,         &real_uid },
 481   { "callout_address",     vtype_stringptr,   &callout_address },
 482   { "compile_date",        vtype_stringptr,   &version_date },
 483   { "compile_number",      vtype_stringptr,   &version_cnumber },
 484   { "config_dir",          vtype_stringptr,   &config_main_directory },
 485   { "config_file",         vtype_stringptr,   &config_main_filename },
 486   { "csa_status",          vtype_stringptr,   &csa_status },
 487 #ifdef EXPERIMENTAL_DCC
 488   { "dcc_header",          vtype_stringptr,   &dcc_header },
 489   { "dcc_result",          vtype_stringptr,   &dcc_result },
 490 #endif
 491 #ifndef DISABLE_DKIM
 492   { "dkim_algo",           vtype_dkim,        (void *)DKIM_ALGO },
 493   { "dkim_bodylength",     vtype_dkim,        (void *)DKIM_BODYLENGTH },
 494   { "dkim_canon_body",     vtype_dkim,        (void *)DKIM_CANON_BODY },
 495   { "dkim_canon_headers",  vtype_dkim,        (void *)DKIM_CANON_HEADERS },
 496   { "dkim_copiedheaders",  vtype_dkim,        (void *)DKIM_COPIEDHEADERS },
 497   { "dkim_created",        vtype_dkim,        (void *)DKIM_CREATED },
 498   { "dkim_cur_signer",     vtype_stringptr,   &dkim_cur_signer },
 499   { "dkim_domain",         vtype_stringptr,   &dkim_signing_domain },
 500   { "dkim_expires",        vtype_dkim,        (void *)DKIM_EXPIRES },
 501   { "dkim_headernames",    vtype_dkim,        (void *)DKIM_HEADERNAMES },
 502   { "dkim_identity",       vtype_dkim,        (void *)DKIM_IDENTITY },
 503   { "dkim_key_granularity",vtype_dkim,        (void *)DKIM_KEY_GRANULARITY },
 504   { "dkim_key_length",     vtype_int,         &dkim_key_length },
 505   { "dkim_key_nosubdomains",vtype_dkim,       (void *)DKIM_NOSUBDOMAINS },
 506   { "dkim_key_notes",      vtype_dkim,        (void *)DKIM_KEY_NOTES },
 507   { "dkim_key_srvtype",    vtype_dkim,        (void *)DKIM_KEY_SRVTYPE },
 508   { "dkim_key_testing",    vtype_dkim,        (void *)DKIM_KEY_TESTING },
 509   { "dkim_selector",       vtype_stringptr,   &dkim_signing_selector },
 510   { "dkim_signers",        vtype_stringptr,   &dkim_signers },
 511   { "dkim_verify_reason",  vtype_dkim,        (void *)DKIM_VERIFY_REASON },
 512   { "dkim_verify_status",  vtype_dkim,        (void *)DKIM_VERIFY_STATUS},
 513 #endif
 514 #ifdef EXPERIMENTAL_DMARC
 515   { "dmarc_ar_header",     vtype_stringptr,   &dmarc_ar_header },
 516   { "dmarc_domain_policy", vtype_stringptr,   &dmarc_domain_policy },
 517   { "dmarc_status",        vtype_stringptr,   &dmarc_status },
 518   { "dmarc_status_text",   vtype_stringptr,   &dmarc_status_text },
 519   { "dmarc_used_domain",   vtype_stringptr,   &dmarc_used_domain },
 520 #endif
 521   { "dnslist_domain",      vtype_stringptr,   &dnslist_domain },
 522   { "dnslist_matched",     vtype_stringptr,   &dnslist_matched },
 523   { "dnslist_text",        vtype_stringptr,   &dnslist_text },
 524   { "dnslist_value",       vtype_stringptr,   &dnslist_value },
 525   { "domain",              vtype_stringptr,   &deliver_domain },
 526   { "domain_data",         vtype_stringptr,   &deliver_domain_data },
 527 #ifndef DISABLE_EVENT
 528   { "event_data",          vtype_stringptr,   &event_data },
 529
 530   /*XXX want to use generic vars for as many of these as possible*/
 531   { "event_defer_errno",   vtype_int,         &event_defer_errno },
 532
 533   { "event_name",          vtype_stringptr,   &event_name },
 534 #endif
 535   { "exim_gid",            vtype_gid,         &exim_gid },
 536   { "exim_path",           vtype_stringptr,   &exim_path },
 537   { "exim_uid",            vtype_uid,         &exim_uid },
 538   { "exim_version",        vtype_stringptr,   &version_string },
 539   { "headers_added",       vtype_string_func, &fn_hdrs_added },
 540   { "home",                vtype_stringptr,   &deliver_home },
 541   { "host",                vtype_stringptr,   &deliver_host },
 542   { "host_address",        vtype_stringptr,   &deliver_host_address },
 543   { "host_data",           vtype_stringptr,   &host_data },
 544   { "host_lookup_deferred",vtype_int,         &host_lookup_deferred },
 545   { "host_lookup_failed",  vtype_int,         &host_lookup_failed },
 546   { "host_port",           vtype_int,         &deliver_host_port },
 547   { "initial_cwd",         vtype_stringptr,   &initial_cwd },
 548   { "inode",               vtype_ino,         &deliver_inode },
 549   { "interface_address",   vtype_stringptr,   &interface_address },
 550   { "interface_port",      vtype_int,         &interface_port },
 551   { "item",                vtype_stringptr,   &iterate_item },
 552   #ifdef LOOKUP_LDAP
 553   { "ldap_dn",             vtype_stringptr,   &eldap_dn },
 554   #endif
 555   { "load_average",        vtype_load_avg,    NULL },
 556   { "local_part",          vtype_stringptr,   &deliver_localpart },
 557   { "local_part_data",     vtype_stringptr,   &deliver_localpart_data },
 558   { "local_part_prefix",   vtype_stringptr,   &deliver_localpart_prefix },
 559   { "local_part_suffix",   vtype_stringptr,   &deliver_localpart_suffix },
 560   { "local_scan_data",     vtype_stringptr,   &local_scan_data },
 561   { "local_user_gid",      vtype_gid,         &local_user_gid },
 562   { "local_user_uid",      vtype_uid,         &local_user_uid },
 563   { "localhost_number",    vtype_int,         &host_number },
 564   { "log_inodes",          vtype_pinodes,     (void *)FALSE },
 565   { "log_space",           vtype_pspace,      (void *)FALSE },
 566   { "lookup_dnssec_authenticated",vtype_stringptr,&lookup_dnssec_authenticated},
 567   { "mailstore_basename",  vtype_stringptr,   &mailstore_basename },
 568 #ifdef WITH_CONTENT_SCAN
 569   { "malware_name",        vtype_stringptr,   &malware_name },
 570 #endif
 571   { "max_received_linelength", vtype_int,     &max_received_linelength },
 572   { "message_age",         vtype_int,         &message_age },
 573   { "message_body",        vtype_msgbody,     &message_body },
 574   { "message_body_end",    vtype_msgbody_end, &message_body_end },
 575   { "message_body_size",   vtype_int,         &message_body_size },
 576   { "message_exim_id",     vtype_stringptr,   &message_id },
 577   { "message_headers",     vtype_msgheaders,  NULL },
 578   { "message_headers_raw", vtype_msgheaders_raw, NULL },
 579   { "message_id",          vtype_stringptr,   &message_id },
 580   { "message_linecount",   vtype_int,         &message_linecount },
 581   { "message_size",        vtype_int,         &message_size },
 582 #ifdef SUPPORT_I18N
 583   { "message_smtputf8",    vtype_bool,        &message_smtputf8 },
 584 #endif
 585 #ifdef WITH_CONTENT_SCAN
 586   { "mime_anomaly_level",  vtype_int,         &mime_anomaly_level },
 587   { "mime_anomaly_text",   vtype_stringptr,   &mime_anomaly_text },
 588   { "mime_boundary",       vtype_stringptr,   &mime_boundary },
 589   { "mime_charset",        vtype_stringptr,   &mime_charset },
 590   { "mime_content_description", vtype_stringptr, &mime_content_description },
 591   { "mime_content_disposition", vtype_stringptr, &mime_content_disposition },
 592   { "mime_content_id",     vtype_stringptr,   &mime_content_id },
 593   { "mime_content_size",   vtype_int,         &mime_content_size },
 594   { "mime_content_transfer_encoding",vtype_stringptr, &mime_content_transfer_encoding },
 595   { "mime_content_type",   vtype_stringptr,   &mime_content_type },
 596   { "mime_decoded_filename", vtype_stringptr, &mime_decoded_filename },
 597   { "mime_filename",       vtype_stringptr,   &mime_filename },
 598   { "mime_is_coverletter", vtype_int,         &mime_is_coverletter },
 599   { "mime_is_multipart",   vtype_int,         &mime_is_multipart },
 600   { "mime_is_rfc822",      vtype_int,         &mime_is_rfc822 },
 601   { "mime_part_count",     vtype_int,         &mime_part_count },
 602 #endif
 603   { "n0",                  vtype_filter_int,  &filter_n[0] },
 604   { "n1",                  vtype_filter_int,  &filter_n[1] },
 605   { "n2",                  vtype_filter_int,  &filter_n[2] },
 606   { "n3",                  vtype_filter_int,  &filter_n[3] },
 607   { "n4",                  vtype_filter_int,  &filter_n[4] },
 608   { "n5",                  vtype_filter_int,  &filter_n[5] },
 609   { "n6",                  vtype_filter_int,  &filter_n[6] },
 610   { "n7",                  vtype_filter_int,  &filter_n[7] },
 611   { "n8",                  vtype_filter_int,  &filter_n[8] },
 612   { "n9",                  vtype_filter_int,  &filter_n[9] },
 613   { "original_domain",     vtype_stringptr,   &deliver_domain_orig },
 614   { "original_local_part", vtype_stringptr,   &deliver_localpart_orig },
 615   { "originator_gid",      vtype_gid,         &originator_gid },
 616   { "originator_uid",      vtype_uid,         &originator_uid },
 617   { "parent_domain",       vtype_stringptr,   &deliver_domain_parent },
 618   { "parent_local_part",   vtype_stringptr,   &deliver_localpart_parent },
 619   { "pid",                 vtype_pid,         NULL },
 620 #ifndef DISABLE_PRDR
 621   { "prdr_requested",      vtype_bool,        &prdr_requested },
 622 #endif
 623   { "primary_hostname",    vtype_stringptr,   &primary_hostname },
 624 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS)
 625   { "proxy_external_address",vtype_stringptr, &proxy_external_address },
 626   { "proxy_external_port", vtype_int,         &proxy_external_port },
 627   { "proxy_local_address", vtype_stringptr,   &proxy_local_address },
 628   { "proxy_local_port",    vtype_int,         &proxy_local_port },
 629   { "proxy_session",       vtype_bool,        &proxy_session },
 630 #endif
 631   { "prvscheck_address",   vtype_stringptr,   &prvscheck_address },
 632   { "prvscheck_keynum",    vtype_stringptr,   &prvscheck_keynum },
 633   { "prvscheck_result",    vtype_stringptr,   &prvscheck_result },
 634   { "qualify_domain",      vtype_stringptr,   &qualify_domain_sender },
 635   { "qualify_recipient",   vtype_stringptr,   &qualify_domain_recipient },
 636   { "queue_name",          vtype_stringptr,   &queue_name },
 637   { "rcpt_count",          vtype_int,         &rcpt_count },
 638   { "rcpt_defer_count",    vtype_int,         &rcpt_defer_count },
 639   { "rcpt_fail_count",     vtype_int,         &rcpt_fail_count },
 640   { "received_count",      vtype_int,         &received_count },
 641   { "received_for",        vtype_stringptr,   &received_for },
 642   { "received_ip_address", vtype_stringptr,   &interface_address },
 643   { "received_port",       vtype_int,         &interface_port },
 644   { "received_protocol",   vtype_stringptr,   &received_protocol },
 645   { "received_time",       vtype_int,         &received_time },
 646   { "recipient_data",      vtype_stringptr,   &recipient_data },
 647   { "recipient_verify_failure",vtype_stringptr,&recipient_verify_failure },
 648   { "recipients",          vtype_string_func, &fn_recipients },
 649   { "recipients_count",    vtype_int,         &recipients_count },
 650 #ifdef WITH_CONTENT_SCAN
 651   { "regex_match_string",  vtype_stringptr,   &regex_match_string },
 652 #endif
 653   { "reply_address",       vtype_reply,       NULL },
 654   { "return_path",         vtype_stringptr,   &return_path },
 655   { "return_size_limit",   vtype_int,         &bounce_return_size_limit },
 656   { "router_name",         vtype_stringptr,   &router_name },
 657   { "runrc",               vtype_int,         &runrc },
 658   { "self_hostname",       vtype_stringptr,   &self_hostname },
 659   { "sender_address",      vtype_stringptr,   &sender_address },
 660   { "sender_address_data", vtype_stringptr,   &sender_address_data },
 661   { "sender_address_domain", vtype_domain,    &sender_address },
 662   { "sender_address_local_part", vtype_localpart, &sender_address },
 663   { "sender_data",         vtype_stringptr,   &sender_data },
 664   { "sender_fullhost",     vtype_stringptr,   &sender_fullhost },
 665   { "sender_helo_dnssec",  vtype_bool,        &sender_helo_dnssec },
 666   { "sender_helo_name",    vtype_stringptr,   &sender_helo_name },
 667   { "sender_host_address", vtype_stringptr,   &sender_host_address },
 668   { "sender_host_authenticated",vtype_stringptr, &sender_host_authenticated },
 669   { "sender_host_dnssec",  vtype_bool,        &sender_host_dnssec },
 670   { "sender_host_name",    vtype_host_lookup, NULL },
 671   { "sender_host_port",    vtype_int,         &sender_host_port },
 672   { "sender_ident",        vtype_stringptr,   &sender_ident },
 673   { "sender_rate",         vtype_stringptr,   &sender_rate },
 674   { "sender_rate_limit",   vtype_stringptr,   &sender_rate_limit },
 675   { "sender_rate_period",  vtype_stringptr,   &sender_rate_period },
 676   { "sender_rcvhost",      vtype_stringptr,   &sender_rcvhost },
 677   { "sender_verify_failure",vtype_stringptr,  &sender_verify_failure },
 678   { "sending_ip_address",  vtype_stringptr,   &sending_ip_address },
 679   { "sending_port",        vtype_int,         &sending_port },
 680   { "smtp_active_hostname", vtype_stringptr,  &smtp_active_hostname },
 681   { "smtp_command",        vtype_stringptr,   &smtp_cmd_buffer },
 682   { "smtp_command_argument", vtype_stringptr, &smtp_cmd_argument },
 683   { "smtp_count_at_connection_start", vtype_int, &smtp_accept_count },
 684   { "smtp_notquit_reason", vtype_stringptr,   &smtp_notquit_reason },
 685   { "sn0",                 vtype_filter_int,  &filter_sn[0] },
 686   { "sn1",                 vtype_filter_int,  &filter_sn[1] },
 687   { "sn2",                 vtype_filter_int,  &filter_sn[2] },
 688   { "sn3",                 vtype_filter_int,  &filter_sn[3] },
 689   { "sn4",                 vtype_filter_int,  &filter_sn[4] },
 690   { "sn5",                 vtype_filter_int,  &filter_sn[5] },
 691   { "sn6",                 vtype_filter_int,  &filter_sn[6] },
 692   { "sn7",                 vtype_filter_int,  &filter_sn[7] },
 693   { "sn8",                 vtype_filter_int,  &filter_sn[8] },
 694   { "sn9",                 vtype_filter_int,  &filter_sn[9] },
 695 #ifdef WITH_CONTENT_SCAN
 696   { "spam_action",         vtype_stringptr,   &spam_action },
 697   { "spam_bar",            vtype_stringptr,   &spam_bar },
 698   { "spam_report",         vtype_stringptr,   &spam_report },
 699   { "spam_score",          vtype_stringptr,   &spam_score },
 700   { "spam_score_int",      vtype_stringptr,   &spam_score_int },
 701 #endif
 702 #ifdef EXPERIMENTAL_SPF
 703   { "spf_guess",           vtype_stringptr,   &spf_guess },
 704   { "spf_header_comment",  vtype_stringptr,   &spf_header_comment },
 705   { "spf_received",        vtype_stringptr,   &spf_received },
 706   { "spf_result",          vtype_stringptr,   &spf_result },
 707   { "spf_smtp_comment",    vtype_stringptr,   &spf_smtp_comment },
 708 #endif
 709   { "spool_directory",     vtype_stringptr,   &spool_directory },
 710   { "spool_inodes",        vtype_pinodes,     (void *)TRUE },
 711   { "spool_space",         vtype_pspace,      (void *)TRUE },
 712 #ifdef EXPERIMENTAL_SRS
 713   { "srs_db_address",      vtype_stringptr,   &srs_db_address },
 714   { "srs_db_key",          vtype_stringptr,   &srs_db_key },
 715   { "srs_orig_recipient",  vtype_stringptr,   &srs_orig_recipient },
 716   { "srs_orig_sender",     vtype_stringptr,   &srs_orig_sender },
 717   { "srs_recipient",       vtype_stringptr,   &srs_recipient },
 718   { "srs_status",          vtype_stringptr,   &srs_status },
 719 #endif
 720   { "thisaddress",         vtype_stringptr,   &filter_thisaddress },
 721
 722   /* The non-(in,out) variables are now deprecated */
 723   { "tls_bits",            vtype_int,         &tls_in.bits },
 724   { "tls_certificate_verified", vtype_int,    &tls_in.certificate_verified },
 725   { "tls_cipher",          vtype_stringptr,   &tls_in.cipher },
 726
 727   { "tls_in_bits",         vtype_int,         &tls_in.bits },
 728   { "tls_in_certificate_verified", vtype_int, &tls_in.certificate_verified },
 729   { "tls_in_cipher",       vtype_stringptr,   &tls_in.cipher },
 730   { "tls_in_ocsp",         vtype_int,         &tls_in.ocsp },
 731   { "tls_in_ourcert",      vtype_cert,        &tls_in.ourcert },
 732   { "tls_in_peercert",     vtype_cert,        &tls_in.peercert },
 733   { "tls_in_peerdn",       vtype_stringptr,   &tls_in.peerdn },
 734 #if defined(SUPPORT_TLS)
 735   { "tls_in_sni",          vtype_stringptr,   &tls_in.sni },
 736 #endif
 737   { "tls_out_bits",        vtype_int,         &tls_out.bits },
 738   { "tls_out_certificate_verified", vtype_int,&tls_out.certificate_verified },
 739   { "tls_out_cipher",      vtype_stringptr,   &tls_out.cipher },
 740 #ifdef EXPERIMENTAL_DANE
 741   { "tls_out_dane",        vtype_bool,        &tls_out.dane_verified },
 742 #endif
 743   { "tls_out_ocsp",        vtype_int,         &tls_out.ocsp },
 744   { "tls_out_ourcert",     vtype_cert,        &tls_out.ourcert },
 745   { "tls_out_peercert",    vtype_cert,        &tls_out.peercert },
 746   { "tls_out_peerdn",      vtype_stringptr,   &tls_out.peerdn },
 747 #if defined(SUPPORT_TLS)
 748   { "tls_out_sni",         vtype_stringptr,   &tls_out.sni },
 749 #endif
 750 #ifdef EXPERIMENTAL_DANE
 751   { "tls_out_tlsa_usage",  vtype_int,         &tls_out.tlsa_usage },
 752 #endif
 753
 754   { "tls_peerdn",          vtype_stringptr,   &tls_in.peerdn }, /* mind the alphabetical order! */
 755 #if defined(SUPPORT_TLS)
 756   { "tls_sni",             vtype_stringptr,   &tls_in.sni },    /* mind the alphabetical order! */
 757 #endif
 758
 759   { "tod_bsdinbox",        vtype_todbsdin,    NULL },
 760   { "tod_epoch",           vtype_tode,        NULL },
 761   { "tod_epoch_l",         vtype_todel,       NULL },
 762   { "tod_full",            vtype_todf,        NULL },
 763   { "tod_log",             vtype_todl,        NULL },
 764   { "tod_logfile",         vtype_todlf,       NULL },
 765   { "tod_zone",            vtype_todzone,     NULL },
 766   { "tod_zulu",            vtype_todzulu,     NULL },
 767   { "transport_name",      vtype_stringptr,   &transport_name },
 768   { "value",               vtype_stringptr,   &lookup_value },
 769   { "verify_mode",         vtype_stringptr,   &verify_mode },
 770   { "version_number",      vtype_stringptr,   &version_string },
 771   { "warn_message_delay",  vtype_stringptr,   &warnmsg_delay },
 772   { "warn_message_recipient",vtype_stringptr, &warnmsg_recipients },
 773   { "warn_message_recipients",vtype_stringptr,&warnmsg_recipients },
 774   { "warnmsg_delay",       vtype_stringptr,   &warnmsg_delay },
 775   { "warnmsg_recipient",   vtype_stringptr,   &warnmsg_recipients },
 776   { "warnmsg_recipients",  vtype_stringptr,   &warnmsg_recipients }
 777 };
 778
 779 static int var_table_size = nelem(var_table);
 780 static uschar var_buffer[256];
 781 static BOOL malformed_header;
 782
 783 /* For textual hashes */
 784
 785 static const char *hashcodes = "abcdefghijklmnopqrtsuvwxyz"
 786                                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 787                                "0123456789";
 788
 789 enum { HMAC_MD5, HMAC_SHA1 };
 790
 791 /* For numeric hashes */
 792
 793 static unsigned int prime[] = {
 794   2,   3,   5,   7,  11,  13,  17,  19,  23,  29,
 795  31,  37,  41,  43,  47,  53,  59,  61,  67,  71,
 796  73,  79,  83,  89,  97, 101, 103, 107, 109, 113};
 797
 798 /* For printing modes in symbolic form */
 799
 800 static uschar *mtable_normal[] =
 801   { US"---", US"--x", US"-w-", US"-wx", US"r--", US"r-x", US"rw-", US"rwx" };
 802
 803 static uschar *mtable_setid[] =
 804   { US"--S", US"--s", US"-wS", US"-ws", US"r-S", US"r-s", US"rwS", US"rws" };
 805
 806 static uschar *mtable_sticky[] =
 807   { US"--T", US"--t", US"-wT", US"-wt", US"r-T", US"r-t", US"rwT", US"rwt" };
 808
 809
 810
 811 /*************************************************
 812 *           Tables for UTF-8 support             *
 813 *************************************************/
 814
 815 /* Table of the number of extra characters, indexed by the first character
 816 masked with 0x3f. The highest number for a valid UTF-8 character is in fact
 817 0x3d. */
 818
 819 static uschar utf8_table1[] = {
 820   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 821   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 822   2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
 823   3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5 };
 824
 825 /* These are the masks for the data bits in the first byte of a character,
 826 indexed by the number of additional bytes. */
 827
 828 static int utf8_table2[] = { 0xff, 0x1f, 0x0f, 0x07, 0x03, 0x01};
 829
 830 /* Get the next UTF-8 character, advancing the pointer. */
 831
 832 #define GETUTF8INC(c, ptr) \
 833   c = *ptr++; \
 834   if ((c & 0xc0) == 0xc0) \
 835     { \
 836     int a = utf8_table1[c & 0x3f];  /* Number of additional bytes */ \
 837     int s = 6*a; \
 838     c = (c & utf8_table2[a]) << s; \
 839     while (a-- > 0) \
 840       { \
 841       s -= 6; \
 842       c |= (*ptr++ & 0x3f) << s; \
 843       } \
 844     }
 845
 846
 847
 848 static uschar * base32_chars = US"abcdefghijklmnopqrstuvwxyz234567";
 849
 850 /*************************************************
 851 *           Binary chop search on a table        *
 852 *************************************************/
 853
 854 /* This is used for matching expansion items and operators.
 855
 856 Arguments:
 857   name        the name that is being sought
 858   table       the table to search
 859   table_size  the number of items in the table
 860
 861 Returns:      the offset in the table, or -1
 862 */
 863
 864 static int
 865 chop_match(uschar *name, uschar **table, int table_size)
 866 {
 867 uschar **bot = table;
 868 uschar **top = table + table_size;
 869
 870 while (top > bot)
 871   {
 872   uschar **mid = bot + (top - bot)/2;
 873   int c = Ustrcmp(name, *mid);
 874   if (c == 0) return mid - table;
 875   if (c > 0) bot = mid + 1; else top = mid;
 876   }
 877
 878 return -1;
 879 }
 880
 881
 882
 883 /*************************************************
 884 *          Check a condition string              *
 885 *************************************************/
 886
 887 /* This function is called to expand a string, and test the result for a "true"
 888 or "false" value. Failure of the expansion yields FALSE; logged unless it was a
 889 forced fail or lookup defer.
 890
 891 We used to release all store used, but this is not not safe due
 892 to ${dlfunc } and ${acl }.  In any case expand_string_internal()
 893 is reasonably careful to release what it can.
 894
 895 The actual false-value tests should be replicated for ECOND_BOOL_LAX.
 896
 897 Arguments:
 898   condition     the condition string
 899   m1            text to be incorporated in panic error
 900   m2            ditto
 901
 902 Returns:        TRUE if condition is met, FALSE if not
 903 */
 904
 905 BOOL
 906 expand_check_condition(uschar *condition, uschar *m1, uschar *m2)
 907 {
 908 int rc;
 909 uschar *ss = expand_string(condition);
 910 if (ss == NULL)
 911   {
 912   if (!expand_string_forcedfail && !search_find_defer)
 913     log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand condition \"%s\" "
 914       "for %s %s: %s", condition, m1, m2, expand_string_message);
 915   return FALSE;
 916   }
 917 rc = ss[0] != 0 && Ustrcmp(ss, "0") != 0 && strcmpic(ss, US"no") != 0 &&
 918   strcmpic(ss, US"false") != 0;
 919 return rc;
 920 }
 921
 922
 923
 924
 925 /*************************************************
 926 *        Pseudo-random number generation         *
 927 *************************************************/
 928
 929 /* Pseudo-random number generation.  The result is not "expected" to be
 930 cryptographically strong but not so weak that someone will shoot themselves
 931 in the foot using it as a nonce in some email header scheme or whatever
 932 weirdness they'll twist this into.  The result should ideally handle fork().
 933
 934 However, if we're stuck unable to provide this, then we'll fall back to
 935 appallingly bad randomness.
 936
 937 If SUPPORT_TLS is defined then this will not be used except as an emergency
 938 fallback.
 939
 940 Arguments:
 941   max       range maximum
 942 Returns     a random number in range [0, max-1]
 943 */
 944
 945 #ifdef SUPPORT_TLS
 946 # define vaguely_random_number vaguely_random_number_fallback
 947 #endif
 948 int
 949 vaguely_random_number(int max)
 950 {
 951 #ifdef SUPPORT_TLS
 952 # undef vaguely_random_number
 953 #endif
 954   static pid_t pid = 0;
 955   pid_t p2;
 956 #if defined(HAVE_SRANDOM) && !defined(HAVE_SRANDOMDEV)
 957   struct timeval tv;
 958 #endif
 959
 960   p2 = getpid();
 961   if (p2 != pid)
 962     {
 963     if (pid != 0)
 964       {
 965
 966 #ifdef HAVE_ARC4RANDOM
 967       /* cryptographically strong randomness, common on *BSD platforms, not
 968       so much elsewhere.  Alas. */
 969 #ifndef NOT_HAVE_ARC4RANDOM_STIR
 970       arc4random_stir();
 971 #endif
 972 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 973 #ifdef HAVE_SRANDOMDEV
 974       /* uses random(4) for seeding */
 975       srandomdev();
 976 #else
 977       gettimeofday(&tv, NULL);
 978       srandom(tv.tv_sec | tv.tv_usec | getpid());
 979 #endif
 980 #else
 981       /* Poor randomness and no seeding here */
 982 #endif
 983
 984       }
 985     pid = p2;
 986     }
 987
 988 #ifdef HAVE_ARC4RANDOM
 989   return arc4random() % max;
 990 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 991   return random() % max;
 992 #else
 993   /* This one returns a 16-bit number, definitely not crypto-strong */
 994   return random_number(max);
 995 #endif
 996 }
 997
 998
 999
1000
1001 /*************************************************
1002 *             Pick out a name from a string      *
1003 *************************************************/
1004
1005 /* If the name is too long, it is silently truncated.
1006
1007 Arguments:
1008   name      points to a buffer into which to put the name
1009   max       is the length of the buffer
1010   s         points to the first alphabetic character of the name
1011   extras    chars other than alphanumerics to permit
1012
1013 Returns:    pointer to the first character after the name
1014
1015 Note: The test for *s != 0 in the while loop is necessary because
1016 Ustrchr() yields non-NULL if the character is zero (which is not something
1017 I expected). */
1018
1019 static const uschar *
1020 read_name(uschar *name, int max, const uschar *s, uschar *extras)
1021 {
1022 int ptr = 0;
1023 while (*s != 0 && (isalnum(*s) || Ustrchr(extras, *s) != NULL))
1024   {
1025   if (ptr < max-1) name[ptr++] = *s;
1026   s++;
1027   }
1028 name[ptr] = 0;
1029 return s;
1030 }
1031
1032
1033
1034 /*************************************************
1035 *     Pick out the rest of a header name         *
1036 *************************************************/
1037
1038 /* A variable name starting $header_ (or just $h_ for those who like
1039 abbreviations) might not be the complete header name because headers can
1040 contain any printing characters in their names, except ':'. This function is
1041 called to read the rest of the name, chop h[eader]_ off the front, and put ':'
1042 on the end, if the name was terminated by white space.
1043
1044 Arguments:
1045   name      points to a buffer in which the name read so far exists
1046   max       is the length of the buffer
1047   s         points to the first character after the name so far, i.e. the
1048             first non-alphameric character after $header_xxxxx
1049
1050 Returns:    a pointer to the first character after the header name
1051 */
1052
1053 static const uschar *
1054 read_header_name(uschar *name, int max, const uschar *s)
1055 {
1056 int prelen = Ustrchr(name, '_') - name + 1;
1057 int ptr = Ustrlen(name) - prelen;
1058 if (ptr > 0) memmove(name, name+prelen, ptr);
1059 while (mac_isgraph(*s) && *s != ':')
1060   {
1061   if (ptr < max-1) name[ptr++] = *s;
1062   s++;
1063   }
1064 if (*s == ':') s++;
1065 name[ptr++] = ':';
1066 name[ptr] = 0;
1067 return s;
1068 }
1069
1070
1071
1072 /*************************************************
1073 *           Pick out a number from a string      *
1074 *************************************************/
1075
1076 /* Arguments:
1077   n     points to an integer into which to put the number
1078   s     points to the first digit of the number
1079
1080 Returns:  a pointer to the character after the last digit
1081 */
1082 /*XXX consider expanding to int_eximarith_t.  But the test for
1083 "overbig numbers" in 0002 still needs to overflow it. */
1084
1085 static uschar *
1086 read_number(int *n, uschar *s)
1087 {
1088 *n = 0;
1089 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
1090 return s;
1091 }
1092
1093 static const uschar *
1094 read_cnumber(int *n, const uschar *s)
1095 {
1096 *n = 0;
1097 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
1098 return s;
1099 }
1100
1101
1102
1103 /*************************************************
1104 *        Extract keyed subfield from a string    *
1105 *************************************************/
1106
1107 /* The yield is in dynamic store; NULL means that the key was not found.
1108
1109 Arguments:
1110   key       points to the name of the key
1111   s         points to the string from which to extract the subfield
1112
1113 Returns:    NULL if the subfield was not found, or
1114             a pointer to the subfield's data
1115 */
1116
1117 static uschar *
1118 expand_getkeyed(uschar *key, const uschar *s)
1119 {
1120 int length = Ustrlen(key);
1121 while (isspace(*s)) s++;
1122
1123 /* Loop to search for the key */
1124
1125 while (*s != 0)
1126   {
1127   int dkeylength;
1128   uschar *data;
1129   const uschar *dkey = s;
1130
1131   while (*s != 0 && *s != '=' && !isspace(*s)) s++;
1132   dkeylength = s - dkey;
1133   while (isspace(*s)) s++;
1134   if (*s == '=') while (isspace((*(++s))));
1135
1136   data = string_dequote(&s);
1137   if (length == dkeylength && strncmpic(key, dkey, length) == 0)
1138     return data;
1139
1140   while (isspace(*s)) s++;
1141   }
1142
1143 return NULL;
1144 }
1145
1146
1147
1148 static var_entry *
1149 find_var_ent(uschar * name)
1150 {
1151 int first = 0;
1152 int last = var_table_size;
1153
1154 while (last > first)
1155   {
1156   int middle = (first + last)/2;
1157   int c = Ustrcmp(name, var_table[middle].name);
1158
1159   if (c > 0) { first = middle + 1; continue; }
1160   if (c < 0) { last = middle; continue; }
1161   return &var_table[middle];
1162   }
1163 return NULL;
1164 }
1165
1166 /*************************************************
1167 *   Extract numbered subfield from string        *
1168 *************************************************/
1169
1170 /* Extracts a numbered field from a string that is divided by tokens - for
1171 example a line from /etc/passwd is divided by colon characters.  First field is
1172 numbered one.  Negative arguments count from the right. Zero returns the whole
1173 string. Returns NULL if there are insufficient tokens in the string
1174
1175 ***WARNING***
1176 Modifies final argument - this is a dynamically generated string, so that's OK.
1177
1178 Arguments:
1179   field       number of field to be extracted,
1180                 first field = 1, whole string = 0, last field = -1
1181   separators  characters that are used to break string into tokens
1182   s           points to the string from which to extract the subfield
1183
1184 Returns:      NULL if the field was not found,
1185               a pointer to the field's data inside s (modified to add 0)
1186 */
1187
1188 static uschar *
1189 expand_gettokened (int field, uschar *separators, uschar *s)
1190 {
1191 int sep = 1;
1192 int count;
1193 uschar *ss = s;
1194 uschar *fieldtext = NULL;
1195
1196 if (field == 0) return s;
1197
1198 /* Break the line up into fields in place; for field > 0 we stop when we have
1199 done the number of fields we want. For field < 0 we continue till the end of
1200 the string, counting the number of fields. */
1201
1202 count = (field > 0)? field : INT_MAX;
1203
1204 while (count-- > 0)
1205   {
1206   size_t len;
1207
1208   /* Previous field was the last one in the string. For a positive field
1209   number, this means there are not enough fields. For a negative field number,
1210   check that there are enough, and scan back to find the one that is wanted. */
1211
1212   if (sep == 0)
1213     {
1214     if (field > 0 || (-field) > (INT_MAX - count - 1)) return NULL;
1215     if ((-field) == (INT_MAX - count - 1)) return s;
1216     while (field++ < 0)
1217       {
1218       ss--;
1219       while (ss[-1] != 0) ss--;
1220       }
1221     fieldtext = ss;
1222     break;
1223     }
1224
1225   /* Previous field was not last in the string; save its start and put a
1226   zero at its end. */
1227
1228   fieldtext = ss;
1229   len = Ustrcspn(ss, separators);
1230   sep = ss[len];
1231   ss[len] = 0;
1232   ss += len + 1;
1233   }
1234
1235 return fieldtext;
1236 }
1237
1238
1239 static uschar *
1240 expand_getlistele(int field, const uschar * list)
1241 {
1242 const uschar * tlist= list;
1243 int sep= 0;
1244 uschar dummy;
1245
1246 if(field<0)
1247   {
1248   for(field++; string_nextinlist(&tlist, &sep, &dummy, 1); ) field++;
1249   sep= 0;
1250   }
1251 if(field==0) return NULL;
1252 while(--field>0 && (string_nextinlist(&list, &sep, &dummy, 1))) ;
1253 return string_nextinlist(&list, &sep, NULL, 0);
1254 }
1255
1256
1257 /* Certificate fields, by name.  Worry about by-OID later */
1258 /* Names are chosen to not have common prefixes */
1259
1260 #ifdef SUPPORT_TLS
1261 typedef struct
1262 {
1263 uschar * name;
1264 int      namelen;
1265 uschar * (*getfn)(void * cert, uschar * mod);
1266 } certfield;
1267 static certfield certfields[] =
1268 {                       /* linear search; no special order */
1269   { US"version",         7,  &tls_cert_version },
1270   { US"serial_number",   13, &tls_cert_serial_number },
1271   { US"subject",         7,  &tls_cert_subject },
1272   { US"notbefore",       9,  &tls_cert_not_before },
1273   { US"notafter",        8,  &tls_cert_not_after },
1274   { US"issuer",          6,  &tls_cert_issuer },
1275   { US"signature",       9,  &tls_cert_signature },
1276   { US"sig_algorithm",   13, &tls_cert_signature_algorithm },
1277   { US"subj_altname",    12, &tls_cert_subject_altname },
1278   { US"ocsp_uri",        8,  &tls_cert_ocsp_uri },
1279   { US"crl_uri",         7,  &tls_cert_crl_uri },
1280 };
1281
1282 static uschar *
1283 expand_getcertele(uschar * field, uschar * certvar)
1284 {
1285 var_entry * vp;
1286 certfield * cp;
1287
1288 if (!(vp = find_var_ent(certvar)))
1289   {
1290   expand_string_message =
1291     string_sprintf("no variable named \"%s\"", certvar);
1292   return NULL;          /* Unknown variable name */
1293   }
1294 /* NB this stops us passing certs around in variable.  Might
1295 want to do that in future */
1296 if (vp->type != vtype_cert)
1297   {
1298   expand_string_message =
1299     string_sprintf("\"%s\" is not a certificate", certvar);
1300   return NULL;          /* Unknown variable name */
1301   }
1302 if (!*(void **)vp->value)
1303   return NULL;
1304
1305 if (*field >= '0' && *field <= '9')
1306   return tls_cert_ext_by_oid(*(void **)vp->value, field, 0);
1307
1308 for(cp = certfields;
1309     cp < certfields + nelem(certfields);
1310     cp++)
1311   if (Ustrncmp(cp->name, field, cp->namelen) == 0)
1312     {
1313     uschar * modifier = *(field += cp->namelen) == ','
1314       ? ++field : NULL;
1315     return (*cp->getfn)( *(void **)vp->value, modifier );
1316     }
1317
1318 expand_string_message =
1319   string_sprintf("bad field selector \"%s\" for certextract", field);
1320 return NULL;
1321 }
1322 #endif  /*SUPPORT_TLS*/
1323
1324 /*************************************************
1325 *        Extract a substring from a string       *
1326 *************************************************/
1327
1328 /* Perform the ${substr or ${length expansion operations.
1329
1330 Arguments:
1331   subject     the input string
1332   value1      the offset from the start of the input string to the start of
1333                 the output string; if negative, count from the right.
1334   value2      the length of the output string, or negative (-1) for unset
1335                 if value1 is positive, unset means "all after"
1336                 if value1 is negative, unset means "all before"
1337   len         set to the length of the returned string
1338
1339 Returns:      pointer to the output string, or NULL if there is an error
1340 */
1341
1342 static uschar *
1343 extract_substr(uschar *subject, int value1, int value2, int *len)
1344 {
1345 int sublen = Ustrlen(subject);
1346
1347 if (value1 < 0)    /* count from right */
1348   {
1349   value1 += sublen;
1350
1351   /* If the position is before the start, skip to the start, and adjust the
1352   length. If the length ends up negative, the substring is null because nothing
1353   can precede. This falls out naturally when the length is unset, meaning "all
1354   to the left". */
1355
1356   if (value1 < 0)
1357     {
1358     value2 += value1;
1359     if (value2 < 0) value2 = 0;
1360     value1 = 0;
1361     }
1362
1363   /* Otherwise an unset length => characters before value1 */
1364
1365   else if (value2 < 0)
1366     {
1367     value2 = value1;
1368     value1 = 0;
1369     }
1370   }
1371
1372 /* For a non-negative offset, if the starting position is past the end of the
1373 string, the result will be the null string. Otherwise, an unset length means
1374 "rest"; just set it to the maximum - it will be cut down below if necessary. */
1375
1376 else
1377   {
1378   if (value1 > sublen)
1379     {
1380     value1 = sublen;
1381     value2 = 0;
1382     }
1383   else if (value2 < 0) value2 = sublen;
1384   }
1385
1386 /* Cut the length down to the maximum possible for the offset value, and get
1387 the required characters. */
1388
1389 if (value1 + value2 > sublen) value2 = sublen - value1;
1390 *len = value2;
1391 return subject + value1;
1392 }
1393
1394
1395
1396
1397 /*************************************************
1398 *            Old-style hash of a string          *
1399 *************************************************/
1400
1401 /* Perform the ${hash expansion operation.
1402
1403 Arguments:
1404   subject     the input string (an expanded substring)
1405   value1      the length of the output string; if greater or equal to the
1406                 length of the input string, the input string is returned
1407   value2      the number of hash characters to use, or 26 if negative
1408   len         set to the length of the returned string
1409
1410 Returns:      pointer to the output string, or NULL if there is an error
1411 */
1412
1413 static uschar *
1414 compute_hash(uschar *subject, int value1, int value2, int *len)
1415 {
1416 int sublen = Ustrlen(subject);
1417
1418 if (value2 < 0) value2 = 26;
1419 else if (value2 > Ustrlen(hashcodes))
1420   {
1421   expand_string_message =
1422     string_sprintf("hash count \"%d\" too big", value2);
1423   return NULL;
1424   }
1425
1426 /* Calculate the hash text. We know it is shorter than the original string, so
1427 can safely place it in subject[] (we know that subject is always itself an
1428 expanded substring). */
1429
1430 if (value1 < sublen)
1431   {
1432   int c;
1433   int i = 0;
1434   int j = value1;
1435   while ((c = (subject[j])) != 0)
1436     {
1437     int shift = (c + j++) & 7;
1438     subject[i] ^= (c << shift) | (c >> (8-shift));
1439     if (++i >= value1) i = 0;
1440     }
1441   for (i = 0; i < value1; i++)
1442     subject[i] = hashcodes[(subject[i]) % value2];
1443   }
1444 else value1 = sublen;
1445
1446 *len = value1;
1447 return subject;
1448 }
1449
1450
1451
1452
1453 /*************************************************
1454 *             Numeric hash of a string           *
1455 *************************************************/
1456
1457 /* Perform the ${nhash expansion operation. The first characters of the
1458 string are treated as most important, and get the highest prime numbers.
1459
1460 Arguments:
1461   subject     the input string
1462   value1      the maximum value of the first part of the result
1463   value2      the maximum value of the second part of the result,
1464                 or negative to produce only a one-part result
1465   len         set to the length of the returned string
1466
1467 Returns:  pointer to the output string, or NULL if there is an error.
1468 */
1469
1470 static uschar *
1471 compute_nhash (uschar *subject, int value1, int value2, int *len)
1472 {
1473 uschar *s = subject;
1474 int i = 0;
1475 unsigned long int total = 0; /* no overflow */
1476
1477 while (*s != 0)
1478   {
1479   if (i == 0) i = nelem(prime) - 1;
1480   total += prime[i--] * (unsigned int)(*s++);
1481   }
1482
1483 /* If value2 is unset, just compute one number */
1484
1485 if (value2 < 0)
1486   {
1487   s = string_sprintf("%d", total % value1);
1488   }
1489
1490 /* Otherwise do a div/mod hash */
1491
1492 else
1493   {
1494   total = total % (value1 * value2);
1495   s = string_sprintf("%d/%d", total/value2, total % value2);
1496   }
1497
1498 *len = Ustrlen(s);
1499 return s;
1500 }
1501
1502
1503
1504
1505
1506 /*************************************************
1507 *     Find the value of a header or headers      *
1508 *************************************************/
1509
1510 /* Multiple instances of the same header get concatenated, and this function
1511 can also return a concatenation of all the header lines. When concatenating
1512 specific headers that contain lists of addresses, a comma is inserted between
1513 them. Otherwise we use a straight concatenation. Because some messages can have
1514 pathologically large number of lines, there is a limit on the length that is
1515 returned. Also, to avoid massive store use which would result from using
1516 string_cat() as it copies and extends strings, we do a preliminary pass to find
1517 out exactly how much store will be needed. On "normal" messages this will be
1518 pretty trivial.
1519
1520 Arguments:
1521   name          the name of the header, without the leading $header_ or $h_,
1522                 or NULL if a concatenation of all headers is required
1523   exists_only   TRUE if called from a def: test; don't need to build a string;
1524                 just return a string that is not "" and not "0" if the header
1525                 exists
1526   newsize       return the size of memory block that was obtained; may be NULL
1527                 if exists_only is TRUE
1528   want_raw      TRUE if called for $rh_ or $rheader_ variables; no processing,
1529                 other than concatenating, will be done on the header. Also used
1530                 for $message_headers_raw.
1531   charset       name of charset to translate MIME words to; used only if
1532                 want_raw is false; if NULL, no translation is done (this is
1533                 used for $bh_ and $bheader_)
1534
1535 Returns:        NULL if the header does not exist, else a pointer to a new
1536                 store block
1537 */
1538
1539 static uschar *
1540 find_header(uschar *name, BOOL exists_only, int *newsize, BOOL want_raw,
1541   uschar *charset)
1542 {
1543 BOOL found = name == NULL;
1544 int comma = 0;
1545 int len = found? 0 : Ustrlen(name);
1546 int i;
1547 uschar *yield = NULL;
1548 uschar *ptr = NULL;
1549
1550 /* Loop for two passes - saves code repetition */
1551
1552 for (i = 0; i < 2; i++)
1553   {
1554   int size = 0;
1555   header_line *h;
1556
1557   for (h = header_list; size < header_insert_maxlen && h != NULL; h = h->next)
1558     {
1559     if (h->type != htype_old && h->text != NULL)  /* NULL => Received: placeholder */
1560       {
1561       if (name == NULL || (len <= h->slen && strncmpic(name, h->text, len) == 0))
1562         {
1563         int ilen;
1564         uschar *t;
1565
1566         if (exists_only) return US"1";      /* don't need actual string */
1567         found = TRUE;
1568         t = h->text + len;                  /* text to insert */
1569         if (!want_raw)                      /* unless wanted raw, */
1570           while (isspace(*t)) t++;          /* remove leading white space */
1571         ilen = h->slen - (t - h->text);     /* length to insert */
1572
1573         /* Unless wanted raw, remove trailing whitespace, including the
1574         newline. */
1575
1576         if (!want_raw)
1577           while (ilen > 0 && isspace(t[ilen-1])) ilen--;
1578
1579         /* Set comma = 1 if handling a single header and it's one of those
1580         that contains an address list, except when asked for raw headers. Only
1581         need to do this once. */
1582
1583         if (!want_raw && name != NULL && comma == 0 &&
1584             Ustrchr("BCFRST", h->type) != NULL)
1585           comma = 1;
1586
1587         /* First pass - compute total store needed; second pass - compute
1588         total store used, including this header. */
1589
1590         size += ilen + comma + 1;  /* +1 for the newline */
1591
1592         /* Second pass - concatenate the data, up to a maximum. Note that
1593         the loop stops when size hits the limit. */
1594
1595         if (i != 0)
1596           {
1597           if (size > header_insert_maxlen)
1598             {
1599             ilen -= size - header_insert_maxlen - 1;
1600             comma = 0;
1601             }
1602           Ustrncpy(ptr, t, ilen);
1603           ptr += ilen;
1604
1605           /* For a non-raw header, put in the comma if needed, then add
1606           back the newline we removed above, provided there was some text in
1607           the header. */
1608
1609           if (!want_raw && ilen > 0)
1610             {
1611             if (comma != 0) *ptr++ = ',';
1612             *ptr++ = '\n';
1613             }
1614           }
1615         }
1616       }
1617     }
1618
1619   /* At end of first pass, return NULL if no header found. Then truncate size
1620   if necessary, and get the buffer to hold the data, returning the buffer size.
1621   */
1622
1623   if (i == 0)
1624     {
1625     if (!found) return NULL;
1626     if (size > header_insert_maxlen) size = header_insert_maxlen;
1627     *newsize = size + 1;
1628     ptr = yield = store_get(*newsize);
1629     }
1630   }
1631
1632 /* That's all we do for raw header expansion. */
1633
1634 if (want_raw)
1635   {
1636   *ptr = 0;
1637   }
1638
1639 /* Otherwise, remove a final newline and a redundant added comma. Then we do
1640 RFC 2047 decoding, translating the charset if requested. The rfc2047_decode2()
1641 function can return an error with decoded data if the charset translation
1642 fails. If decoding fails, it returns NULL. */
1643
1644 else
1645   {
1646   uschar *decoded, *error;
1647   if (ptr > yield && ptr[-1] == '\n') ptr--;
1648   if (ptr > yield && comma != 0 && ptr[-1] == ',') ptr--;
1649   *ptr = 0;
1650   decoded = rfc2047_decode2(yield, check_rfc2047_length, charset, '?', NULL,
1651     newsize, &error);
1652   if (error != NULL)
1653     {
1654     DEBUG(D_any) debug_printf("*** error in RFC 2047 decoding: %s\n"
1655       "    input was: %s\n", error, yield);
1656     }
1657   if (decoded != NULL) yield = decoded;
1658   }
1659
1660 return yield;
1661 }
1662
1663
1664
1665
1666 /*************************************************
1667 *               Return list of recipients        *
1668 *************************************************/
1669 /* A recipients list is available only during system message filtering,
1670 during ACL processing after DATA, and while expanding pipe commands
1671 generated from a system filter, but not elsewhere. */
1672
1673 static uschar *
1674 fn_recipients(void)
1675 {
1676 if (!enable_dollar_recipients) return NULL; else
1677   {
1678   int size = 128;
1679   int ptr = 0;
1680   int i;
1681   uschar * s = store_get(size);
1682   for (i = 0; i < recipients_count; i++)
1683     {
1684     if (i != 0) s = string_catn(s, &size, &ptr, US", ", 2);
1685     s = string_cat(s, &size, &ptr, recipients_list[i].address);
1686     }
1687   s[ptr] = 0;     /* string_cat() leaves room */
1688   return s;
1689   }
1690 }
1691
1692
1693 /*************************************************
1694 *               Find value of a variable         *
1695 *************************************************/
1696
1697 /* The table of variables is kept in alphabetic order, so we can search it
1698 using a binary chop. The "choplen" variable is nothing to do with the binary
1699 chop.
1700
1701 Arguments:
1702   name          the name of the variable being sought
1703   exists_only   TRUE if this is a def: test; passed on to find_header()
1704   skipping      TRUE => skip any processing evaluation; this is not the same as
1705                   exists_only because def: may test for values that are first
1706                   evaluated here
1707   newsize       pointer to an int which is initially zero; if the answer is in
1708                 a new memory buffer, *newsize is set to its size
1709
1710 Returns:        NULL if the variable does not exist, or
1711                 a pointer to the variable's contents, or
1712                 something non-NULL if exists_only is TRUE
1713 */
1714
1715 static uschar *
1716 find_variable(uschar *name, BOOL exists_only, BOOL skipping, int *newsize)
1717 {
1718 var_entry * vp;
1719 uschar *s, *domain;
1720 uschar **ss;
1721 void * val;
1722
1723 /* Handle ACL variables, whose names are of the form acl_cxxx or acl_mxxx.
1724 Originally, xxx had to be a number in the range 0-9 (later 0-19), but from
1725 release 4.64 onwards arbitrary names are permitted, as long as the first 5
1726 characters are acl_c or acl_m and the sixth is either a digit or an underscore
1727 (this gave backwards compatibility at the changeover). There may be built-in
1728 variables whose names start acl_ but they should never start in this way. This
1729 slightly messy specification is a consequence of the history, needless to say.
1730
1731 If an ACL variable does not exist, treat it as empty, unless strict_acl_vars is
1732 set, in which case give an error. */
1733
1734 if ((Ustrncmp(name, "acl_c", 5) == 0 || Ustrncmp(name, "acl_m", 5) == 0) &&
1735      !isalpha(name[5]))
1736   {
1737   tree_node *node =
1738     tree_search((name[4] == 'c')? acl_var_c : acl_var_m, name + 4);
1739   return node ? node->data.ptr : strict_acl_vars ? NULL : US"";
1740   }
1741
1742 /* Handle $auth<n> variables. */
1743
1744 if (Ustrncmp(name, "auth", 4) == 0)
1745   {
1746   uschar *endptr;
1747   int n = Ustrtoul(name + 4, &endptr, 10);
1748   if (*endptr == 0 && n != 0 && n <= AUTH_VARS)
1749     return !auth_vars[n-1] ? US"" : auth_vars[n-1];
1750   }
1751 else if (Ustrncmp(name, "regex", 5) == 0)
1752   {
1753   uschar *endptr;
1754   int n = Ustrtoul(name + 5, &endptr, 10);
1755   if (*endptr == 0 && n != 0 && n <= REGEX_VARS)
1756     return !regex_vars[n-1] ? US"" : regex_vars[n-1];
1757   }
1758
1759 /* For all other variables, search the table */
1760
1761 if (!(vp = find_var_ent(name)))
1762   return NULL;          /* Unknown variable name */
1763
1764 /* Found an existing variable. If in skipping state, the value isn't needed,
1765 and we want to avoid processing (such as looking up the host name). */
1766
1767 if (skipping)
1768   return US"";
1769
1770 val = vp->value;
1771 switch (vp->type)
1772   {
1773   case vtype_filter_int:
1774     if (!filter_running) return NULL;
1775     /* Fall through */
1776     /* VVVVVVVVVVVV */
1777   case vtype_int:
1778     sprintf(CS var_buffer, "%d", *(int *)(val)); /* Integer */
1779     return var_buffer;
1780
1781   case vtype_ino:
1782     sprintf(CS var_buffer, "%ld", (long int)(*(ino_t *)(val))); /* Inode */
1783     return var_buffer;
1784
1785   case vtype_gid:
1786     sprintf(CS var_buffer, "%ld", (long int)(*(gid_t *)(val))); /* gid */
1787     return var_buffer;
1788
1789   case vtype_uid:
1790     sprintf(CS var_buffer, "%ld", (long int)(*(uid_t *)(val))); /* uid */
1791     return var_buffer;
1792
1793   case vtype_bool:
1794     sprintf(CS var_buffer, "%s", *(BOOL *)(val) ? "yes" : "no"); /* bool */
1795     return var_buffer;
1796
1797   case vtype_stringptr:                      /* Pointer to string */
1798     return (s = *((uschar **)(val))) ? s : US"";
1799
1800   case vtype_pid:
1801     sprintf(CS var_buffer, "%d", (int)getpid()); /* pid */
1802     return var_buffer;
1803
1804   case vtype_load_avg:
1805     sprintf(CS var_buffer, "%d", OS_GETLOADAVG()); /* load_average */
1806     return var_buffer;
1807
1808   case vtype_host_lookup:                    /* Lookup if not done so */
1809     if (sender_host_name == NULL && sender_host_address != NULL &&
1810         !host_lookup_failed && host_name_lookup() == OK)
1811       host_build_sender_fullhost();
1812     return (sender_host_name == NULL)? US"" : sender_host_name;
1813
1814   case vtype_localpart:                      /* Get local part from address */
1815     s = *((uschar **)(val));
1816     if (s == NULL) return US"";
1817     domain = Ustrrchr(s, '@');
1818     if (domain == NULL) return s;
1819     if (domain - s > sizeof(var_buffer) - 1)
1820       log_write(0, LOG_MAIN|LOG_PANIC_DIE, "local part longer than " SIZE_T_FMT
1821           " in string expansion", sizeof(var_buffer));
1822     Ustrncpy(var_buffer, s, domain - s);
1823     var_buffer[domain - s] = 0;
1824     return var_buffer;
1825
1826   case vtype_domain:                         /* Get domain from address */
1827     s = *((uschar **)(val));
1828     if (s == NULL) return US"";
1829     domain = Ustrrchr(s, '@');
1830     return (domain == NULL)? US"" : domain + 1;
1831
1832   case vtype_msgheaders:
1833     return find_header(NULL, exists_only, newsize, FALSE, NULL);
1834
1835   case vtype_msgheaders_raw:
1836     return find_header(NULL, exists_only, newsize, TRUE, NULL);
1837
1838   case vtype_msgbody:                        /* Pointer to msgbody string */
1839   case vtype_msgbody_end:                    /* Ditto, the end of the msg */
1840     ss = (uschar **)(val);
1841     if (*ss == NULL && deliver_datafile >= 0)  /* Read body when needed */
1842       {
1843       uschar *body;
1844       off_t start_offset = SPOOL_DATA_START_OFFSET;
1845       int len = message_body_visible;
1846       if (len > message_size) len = message_size;
1847       *ss = body = store_malloc(len+1);
1848       body[0] = 0;
1849       if (vp->type == vtype_msgbody_end)
1850         {
1851         struct stat statbuf;
1852         if (fstat(deliver_datafile, &statbuf) == 0)
1853           {
1854           start_offset = statbuf.st_size - len;
1855           if (start_offset < SPOOL_DATA_START_OFFSET)
1856             start_offset = SPOOL_DATA_START_OFFSET;
1857           }
1858         }
1859       if (lseek(deliver_datafile, start_offset, SEEK_SET) < 0)
1860         log_write(0, LOG_MAIN|LOG_PANIC_DIE, "deliver_datafile lseek: %s",
1861           strerror(errno));
1862       len = read(deliver_datafile, body, len);
1863       if (len > 0)
1864         {
1865         body[len] = 0;
1866         if (message_body_newlines)   /* Separate loops for efficiency */
1867           while (len > 0)
1868             { if (body[--len] == 0) body[len] = ' '; }
1869         else
1870           while (len > 0)
1871             { if (body[--len] == '\n' || body[len] == 0) body[len] = ' '; }
1872         }
1873       }
1874     return (*ss == NULL)? US"" : *ss;
1875
1876   case vtype_todbsdin:                       /* BSD inbox time of day */
1877     return tod_stamp(tod_bsdin);
1878
1879   case vtype_tode:                           /* Unix epoch time of day */
1880     return tod_stamp(tod_epoch);
1881
1882   case vtype_todel:                          /* Unix epoch/usec time of day */
1883     return tod_stamp(tod_epoch_l);
1884
1885   case vtype_todf:                           /* Full time of day */
1886     return tod_stamp(tod_full);
1887
1888   case vtype_todl:                           /* Log format time of day */
1889     return tod_stamp(tod_log_bare);            /* (without timezone) */
1890
1891   case vtype_todzone:                        /* Time zone offset only */
1892     return tod_stamp(tod_zone);
1893
1894   case vtype_todzulu:                        /* Zulu time */
1895     return tod_stamp(tod_zulu);
1896
1897   case vtype_todlf:                          /* Log file datestamp tod */
1898     return tod_stamp(tod_log_datestamp_daily);
1899
1900   case vtype_reply:                          /* Get reply address */
1901     s = find_header(US"reply-to:", exists_only, newsize, TRUE,
1902       headers_charset);
1903     if (s != NULL) while (isspace(*s)) s++;
1904     if (s == NULL || *s == 0)
1905       {
1906       *newsize = 0;                            /* For the *s==0 case */
1907       s = find_header(US"from:", exists_only, newsize, TRUE, headers_charset);
1908       }
1909     if (s != NULL)
1910       {
1911       uschar *t;
1912       while (isspace(*s)) s++;
1913       for (t = s; *t != 0; t++) if (*t == '\n') *t = ' ';
1914       while (t > s && isspace(t[-1])) t--;
1915       *t = 0;
1916       }
1917     return (s == NULL)? US"" : s;
1918
1919   case vtype_string_func:
1920     {
1921     uschar * (*fn)() = val;
1922     return fn();
1923     }
1924
1925   case vtype_pspace:
1926     {
1927     int inodes;
1928     sprintf(CS var_buffer, "%d",
1929       receive_statvfs(val == (void *)TRUE, &inodes));
1930     }
1931   return var_buffer;
1932
1933   case vtype_pinodes:
1934     {
1935     int inodes;
1936     (void) receive_statvfs(val == (void *)TRUE, &inodes);
1937     sprintf(CS var_buffer, "%d", inodes);
1938     }
1939   return var_buffer;
1940
1941   case vtype_cert:
1942     return *(void **)val ? US"<cert>" : US"";
1943
1944 #ifndef DISABLE_DKIM
1945   case vtype_dkim:
1946     return dkim_exim_expand_query((int)(long)val);
1947 #endif
1948
1949   }
1950
1951 return NULL;  /* Unknown variable. Silences static checkers. */
1952 }
1953
1954
1955
1956
1957 void
1958 modify_variable(uschar *name, void * value)
1959 {
1960 var_entry * vp;
1961 if ((vp = find_var_ent(name))) vp->value = value;
1962 return;          /* Unknown variable name, fail silently */
1963 }
1964
1965
1966
1967
1968
1969
1970 /*************************************************
1971 *           Read and expand substrings           *
1972 *************************************************/
1973
1974 /* This function is called to read and expand argument substrings for various
1975 expansion items. Some have a minimum requirement that is less than the maximum;
1976 in these cases, the first non-present one is set to NULL.
1977
1978 Arguments:
1979   sub        points to vector of pointers to set
1980   n          maximum number of substrings
1981   m          minimum required
1982   sptr       points to current string pointer
1983   skipping   the skipping flag
1984   check_end  if TRUE, check for final '}'
1985   name       name of item, for error message
1986   resetok    if not NULL, pointer to flag - write FALSE if unsafe to reset
1987              the store.
1988
1989 Returns:     0 OK; string pointer updated
1990              1 curly bracketing error (too few arguments)
1991              2 too many arguments (only if check_end is set); message set
1992              3 other error (expansion failure)
1993 */
1994
1995 static int
1996 read_subs(uschar **sub, int n, int m, const uschar **sptr, BOOL skipping,
1997   BOOL check_end, uschar *name, BOOL *resetok)
1998 {
1999 int i;
2000 const uschar *s = *sptr;
2001
2002 while (isspace(*s)) s++;
2003 for (i = 0; i < n; i++)
2004   {
2005   if (*s != '{')
2006     {
2007     if (i < m)
2008       {
2009       expand_string_message = string_sprintf("Not enough arguments for '%s' "
2010         "(min is %d)", name, m);
2011       return 1;
2012       }
2013     sub[i] = NULL;
2014     break;
2015     }
2016   if (!(sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, resetok)))
2017     return 3;
2018   if (*s++ != '}') return 1;
2019   while (isspace(*s)) s++;
2020   }
2021 if (check_end && *s++ != '}')
2022   {
2023   if (s[-1] == '{')
2024     {
2025     expand_string_message = string_sprintf("Too many arguments for '%s' "
2026       "(max is %d)", name, n);
2027     return 2;
2028     }
2029   expand_string_message = string_sprintf("missing '}' after '%s'", name);
2030   return 1;
2031   }
2032
2033 *sptr = s;
2034 return 0;
2035 }
2036
2037
2038
2039
2040 /*************************************************
2041 *     Elaborate message for bad variable         *
2042 *************************************************/
2043
2044 /* For the "unknown variable" message, take a look at the variable's name, and
2045 give additional information about possible ACL variables. The extra information
2046 is added on to expand_string_message.
2047
2048 Argument:   the name of the variable
2049 Returns:    nothing
2050 */
2051
2052 static void
2053 check_variable_error_message(uschar *name)
2054 {
2055 if (Ustrncmp(name, "acl_", 4) == 0)
2056   expand_string_message = string_sprintf("%s (%s)", expand_string_message,
2057     (name[4] == 'c' || name[4] == 'm')?
2058       (isalpha(name[5])?
2059         US"6th character of a user-defined ACL variable must be a digit or underscore" :
2060         US"strict_acl_vars is set"    /* Syntax is OK, it has to be this */
2061       ) :
2062       US"user-defined ACL variables must start acl_c or acl_m");
2063 }
2064
2065
2066
2067 /*
2068 Load args from sub array to globals, and call acl_check().
2069 Sub array will be corrupted on return.
2070
2071 Returns:       OK         access is granted by an ACCEPT verb
2072                DISCARD    access is (apparently) granted by a DISCARD verb
2073                FAIL       access is denied
2074                FAIL_DROP  access is denied; drop the connection
2075                DEFER      can't tell at the moment
2076                ERROR      disaster
2077 */
2078 static int
2079 eval_acl(uschar ** sub, int nsub, uschar ** user_msgp)
2080 {
2081 int i;
2082 int sav_narg = acl_narg;
2083 int ret;
2084 uschar * dummy_logmsg;
2085 extern int acl_where;
2086
2087 if(--nsub > nelem(acl_arg)) nsub = nelem(acl_arg);
2088 for (i = 0; i < nsub && sub[i+1]; i++)
2089   {
2090   uschar * tmp = acl_arg[i];
2091   acl_arg[i] = sub[i+1];        /* place callers args in the globals */
2092   sub[i+1] = tmp;               /* stash the old args using our caller's storage */
2093   }
2094 acl_narg = i;
2095 while (i < nsub)
2096   {
2097   sub[i+1] = acl_arg[i];
2098   acl_arg[i++] = NULL;
2099   }
2100
2101 DEBUG(D_expand)
2102   debug_printf_indent("expanding: acl: %s  arg: %s%s\n",
2103     sub[0],
2104     acl_narg>0 ? acl_arg[0] : US"<none>",
2105     acl_narg>1 ? " +more"   : "");
2106
2107 ret = acl_eval(acl_where, sub[0], user_msgp, &dummy_logmsg);
2108
2109 for (i = 0; i < nsub; i++)
2110   acl_arg[i] = sub[i+1];        /* restore old args */
2111 acl_narg = sav_narg;
2112
2113 return ret;
2114 }
2115
2116
2117
2118
2119 /*************************************************
2120 *        Read and evaluate a condition           *
2121 *************************************************/
2122
2123 /*
2124 Arguments:
2125   s        points to the start of the condition text
2126   resetok  points to a BOOL which is written false if it is unsafe to
2127            free memory. Certain condition types (acl) may have side-effect
2128            allocation which must be preserved.
2129   yield    points to a BOOL to hold the result of the condition test;
2130            if NULL, we are just reading through a condition that is
2131            part of an "or" combination to check syntax, or in a state
2132            where the answer isn't required
2133
2134 Returns:   a pointer to the first character after the condition, or
2135            NULL after an error
2136 */
2137
2138 static const uschar *
2139 eval_condition(const uschar *s, BOOL *resetok, BOOL *yield)
2140 {
2141 BOOL testfor = TRUE;
2142 BOOL tempcond, combined_cond;
2143 BOOL *subcondptr;
2144 BOOL sub2_honour_dollar = TRUE;
2145 int i, rc, cond_type, roffset;
2146 int_eximarith_t num[2];
2147 struct stat statbuf;
2148 uschar name[256];
2149 const uschar *sub[10];
2150
2151 const pcre *re;
2152 const uschar *rerror;
2153
2154 for (;;)
2155   {
2156   while (isspace(*s)) s++;
2157   if (*s == '!') { testfor = !testfor; s++; } else break;
2158   }
2159
2160 /* Numeric comparisons are symbolic */
2161
2162 if (*s == '=' || *s == '>' || *s == '<')
2163   {
2164   int p = 0;
2165   name[p++] = *s++;
2166   if (*s == '=')
2167     {
2168     name[p++] = '=';
2169     s++;
2170     }
2171   name[p] = 0;
2172   }
2173
2174 /* All other conditions are named */
2175
2176 else s = read_name(name, 256, s, US"_");
2177
2178 /* If we haven't read a name, it means some non-alpha character is first. */
2179
2180 if (name[0] == 0)
2181   {
2182   expand_string_message = string_sprintf("condition name expected, "
2183     "but found \"%.16s\"", s);
2184   return NULL;
2185   }
2186
2187 /* Find which condition we are dealing with, and switch on it */
2188
2189 cond_type = chop_match(name, cond_table, nelem(cond_table));
2190 switch(cond_type)
2191   {
2192   /* def: tests for a non-empty variable, or for the existence of a header. If
2193   yield == NULL we are in a skipping state, and don't care about the answer. */
2194
2195   case ECOND_DEF:
2196   if (*s != ':')
2197     {
2198     expand_string_message = US"\":\" expected after \"def\"";
2199     return NULL;
2200     }
2201
2202   s = read_name(name, 256, s+1, US"_");
2203
2204   /* Test for a header's existence. If the name contains a closing brace
2205   character, this may be a user error where the terminating colon has been
2206   omitted. Set a flag to adjust a subsequent error message in this case. */
2207
2208   if (Ustrncmp(name, "h_", 2) == 0 ||
2209       Ustrncmp(name, "rh_", 3) == 0 ||
2210       Ustrncmp(name, "bh_", 3) == 0 ||
2211       Ustrncmp(name, "header_", 7) == 0 ||
2212       Ustrncmp(name, "rheader_", 8) == 0 ||
2213       Ustrncmp(name, "bheader_", 8) == 0)
2214     {
2215     s = read_header_name(name, 256, s);
2216     /* {-for-text-editors */
2217     if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
2218     if (yield != NULL) *yield =
2219       (find_header(name, TRUE, NULL, FALSE, NULL) != NULL) == testfor;
2220     }
2221
2222   /* Test for a variable's having a non-empty value. A non-existent variable
2223   causes an expansion failure. */
2224
2225   else
2226     {
2227     uschar *value = find_variable(name, TRUE, yield == NULL, NULL);
2228     if (value == NULL)
2229       {
2230       expand_string_message = (name[0] == 0)?
2231         string_sprintf("variable name omitted after \"def:\"") :
2232         string_sprintf("unknown variable \"%s\" after \"def:\"", name);
2233       check_variable_error_message(name);
2234       return NULL;
2235       }
2236     if (yield != NULL) *yield = (value[0] != 0) == testfor;
2237     }
2238
2239   return s;
2240
2241
2242   /* first_delivery tests for first delivery attempt */
2243
2244   case ECOND_FIRST_DELIVERY:
2245   if (yield != NULL) *yield = deliver_firsttime == testfor;
2246   return s;
2247
2248
2249   /* queue_running tests for any process started by a queue runner */
2250
2251   case ECOND_QUEUE_RUNNING:
2252   if (yield != NULL) *yield = (queue_run_pid != (pid_t)0) == testfor;
2253   return s;
2254
2255
2256   /* exists:  tests for file existence
2257        isip:  tests for any IP address
2258       isip4:  tests for an IPv4 address
2259       isip6:  tests for an IPv6 address
2260         pam:  does PAM authentication
2261      radius:  does RADIUS authentication
2262    ldapauth:  does LDAP authentication
2263     pwcheck:  does Cyrus SASL pwcheck authentication
2264   */
2265
2266   case ECOND_EXISTS:
2267   case ECOND_ISIP:
2268   case ECOND_ISIP4:
2269   case ECOND_ISIP6:
2270   case ECOND_PAM:
2271   case ECOND_RADIUS:
2272   case ECOND_LDAPAUTH:
2273   case ECOND_PWCHECK:
2274
2275   while (isspace(*s)) s++;
2276   if (*s != '{') goto COND_FAILED_CURLY_START;          /* }-for-text-editors */
2277
2278   sub[0] = expand_string_internal(s+1, TRUE, &s, yield == NULL, TRUE, resetok);
2279   if (sub[0] == NULL) return NULL;
2280   /* {-for-text-editors */
2281   if (*s++ != '}') goto COND_FAILED_CURLY_END;
2282
2283   if (yield == NULL) return s;   /* No need to run the test if skipping */
2284
2285   switch(cond_type)
2286     {
2287     case ECOND_EXISTS:
2288     if ((expand_forbid & RDO_EXISTS) != 0)
2289       {
2290       expand_string_message = US"File existence tests are not permitted";
2291       return NULL;
2292       }
2293     *yield = (Ustat(sub[0], &statbuf) == 0) == testfor;
2294     break;
2295
2296     case ECOND_ISIP:
2297     case ECOND_ISIP4:
2298     case ECOND_ISIP6:
2299     rc = string_is_ip_address(sub[0], NULL);
2300     *yield = ((cond_type == ECOND_ISIP)? (rc != 0) :
2301              (cond_type == ECOND_ISIP4)? (rc == 4) : (rc == 6)) == testfor;
2302     break;
2303
2304     /* Various authentication tests - all optionally compiled */
2305
2306     case ECOND_PAM:
2307     #ifdef SUPPORT_PAM
2308     rc = auth_call_pam(sub[0], &expand_string_message);
2309     goto END_AUTH;
2310     #else
2311     goto COND_FAILED_NOT_COMPILED;
2312     #endif  /* SUPPORT_PAM */
2313
2314     case ECOND_RADIUS:
2315     #ifdef RADIUS_CONFIG_FILE
2316     rc = auth_call_radius(sub[0], &expand_string_message);
2317     goto END_AUTH;
2318     #else
2319     goto COND_FAILED_NOT_COMPILED;
2320     #endif  /* RADIUS_CONFIG_FILE */
2321
2322     case ECOND_LDAPAUTH:
2323     #ifdef LOOKUP_LDAP
2324       {
2325       /* Just to keep the interface the same */
2326       BOOL do_cache;
2327       int old_pool = store_pool;
2328       store_pool = POOL_SEARCH;
2329       rc = eldapauth_find((void *)(-1), NULL, sub[0], Ustrlen(sub[0]), NULL,
2330         &expand_string_message, &do_cache);
2331       store_pool = old_pool;
2332       }
2333     goto END_AUTH;
2334     #else
2335     goto COND_FAILED_NOT_COMPILED;
2336     #endif  /* LOOKUP_LDAP */
2337
2338     case ECOND_PWCHECK:
2339     #ifdef CYRUS_PWCHECK_SOCKET
2340     rc = auth_call_pwcheck(sub[0], &expand_string_message);
2341     goto END_AUTH;
2342     #else
2343     goto COND_FAILED_NOT_COMPILED;
2344     #endif  /* CYRUS_PWCHECK_SOCKET */
2345
2346     #if defined(SUPPORT_PAM) || defined(RADIUS_CONFIG_FILE) || \
2347         defined(LOOKUP_LDAP) || defined(CYRUS_PWCHECK_SOCKET)
2348     END_AUTH:
2349     if (rc == ERROR || rc == DEFER) return NULL;
2350     *yield = (rc == OK) == testfor;
2351     #endif
2352     }
2353   return s;
2354
2355
2356   /* call ACL (in a conditional context).  Accept true, deny false.
2357   Defer is a forced-fail.  Anything set by message= goes to $value.
2358   Up to ten parameters are used; we use the braces round the name+args
2359   like the saslauthd condition does, to permit a variable number of args.
2360   See also the expansion-item version EITEM_ACL and the traditional
2361   acl modifier ACLC_ACL.
2362   Since the ACL may allocate new global variables, tell our caller to not
2363   reclaim memory.
2364   */
2365
2366   case ECOND_ACL:
2367     /* ${if acl {{name}{arg1}{arg2}...}  {yes}{no}} */
2368     {
2369     uschar *sub[10];
2370     uschar *user_msg;
2371     BOOL cond = FALSE;
2372     int size = 0;
2373     int ptr = 0;
2374
2375     while (isspace(*s)) s++;
2376     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /*}*/
2377
2378     switch(read_subs(sub, nelem(sub), 1,
2379       &s, yield == NULL, TRUE, US"acl", resetok))
2380       {
2381       case 1: expand_string_message = US"too few arguments or bracketing "
2382         "error for acl";
2383       case 2:
2384       case 3: return NULL;
2385       }
2386
2387     *resetok = FALSE;   /* eval_acl() might allocate; do not reclaim */
2388     if (yield != NULL) switch(eval_acl(sub, nelem(sub), &user_msg))
2389         {
2390         case OK:
2391           cond = TRUE;
2392         case FAIL:
2393           lookup_value = NULL;
2394           if (user_msg)
2395             {
2396             lookup_value = string_cat(NULL, &size, &ptr, user_msg);
2397             lookup_value[ptr] = '\0';
2398             }
2399           *yield = cond == testfor;
2400           break;
2401
2402         case DEFER:
2403           expand_string_forcedfail = TRUE;
2404           /*FALLTHROUGH*/
2405         default:
2406           expand_string_message = string_sprintf("error from acl \"%s\"", sub[0]);
2407           return NULL;
2408         }
2409     return s;
2410     }
2411
2412
2413   /* saslauthd: does Cyrus saslauthd authentication. Four parameters are used:
2414
2415      ${if saslauthd {{username}{password}{service}{realm}}  {yes}{no}}
2416
2417   However, the last two are optional. That is why the whole set is enclosed
2418   in their own set of braces. */
2419
2420   case ECOND_SASLAUTHD:
2421 #ifndef CYRUS_SASLAUTHD_SOCKET
2422     goto COND_FAILED_NOT_COMPILED;
2423 #else
2424     {
2425     uschar *sub[4];
2426     while (isspace(*s)) s++;
2427     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2428     switch(read_subs(sub, nelem(sub), 2, &s, yield == NULL, TRUE, US"saslauthd",
2429                     resetok))
2430       {
2431       case 1: expand_string_message = US"too few arguments or bracketing "
2432         "error for saslauthd";
2433       case 2:
2434       case 3: return NULL;
2435       }
2436     if (sub[2] == NULL) sub[3] = NULL;  /* realm if no service */
2437     if (yield != NULL)
2438       {
2439       int rc = auth_call_saslauthd(sub[0], sub[1], sub[2], sub[3],
2440         &expand_string_message);
2441       if (rc == ERROR || rc == DEFER) return NULL;
2442       *yield = (rc == OK) == testfor;
2443       }
2444     return s;
2445     }
2446 #endif /* CYRUS_SASLAUTHD_SOCKET */
2447
2448
2449   /* symbolic operators for numeric and string comparison, and a number of
2450   other operators, all requiring two arguments.
2451
2452   crypteq:           encrypts plaintext and compares against an encrypted text,
2453                        using crypt(), crypt16(), MD5 or SHA-1
2454   inlist/inlisti:    checks if first argument is in the list of the second
2455   match:             does a regular expression match and sets up the numerical
2456                        variables if it succeeds
2457   match_address:     matches in an address list
2458   match_domain:      matches in a domain list
2459   match_ip:          matches a host list that is restricted to IP addresses
2460   match_local_part:  matches in a local part list
2461   */
2462
2463   case ECOND_MATCH_ADDRESS:
2464   case ECOND_MATCH_DOMAIN:
2465   case ECOND_MATCH_IP:
2466   case ECOND_MATCH_LOCAL_PART:
2467 #ifndef EXPAND_LISTMATCH_RHS
2468     sub2_honour_dollar = FALSE;
2469 #endif
2470     /* FALLTHROUGH */
2471
2472   case ECOND_CRYPTEQ:
2473   case ECOND_INLIST:
2474   case ECOND_INLISTI:
2475   case ECOND_MATCH:
2476
2477   case ECOND_NUM_L:     /* Numerical comparisons */
2478   case ECOND_NUM_LE:
2479   case ECOND_NUM_E:
2480   case ECOND_NUM_EE:
2481   case ECOND_NUM_G:
2482   case ECOND_NUM_GE:
2483
2484   case ECOND_STR_LT:    /* String comparisons */
2485   case ECOND_STR_LTI:
2486   case ECOND_STR_LE:
2487   case ECOND_STR_LEI:
2488   case ECOND_STR_EQ:
2489   case ECOND_STR_EQI:
2490   case ECOND_STR_GT:
2491   case ECOND_STR_GTI:
2492   case ECOND_STR_GE:
2493   case ECOND_STR_GEI:
2494
2495   for (i = 0; i < 2; i++)
2496     {
2497     /* Sometimes, we don't expand substrings; too many insecure configurations
2498     created using match_address{}{} and friends, where the second param
2499     includes information from untrustworthy sources. */
2500     BOOL honour_dollar = TRUE;
2501     if ((i > 0) && !sub2_honour_dollar)
2502       honour_dollar = FALSE;
2503
2504     while (isspace(*s)) s++;
2505     if (*s != '{')
2506       {
2507       if (i == 0) goto COND_FAILED_CURLY_START;
2508       expand_string_message = string_sprintf("missing 2nd string in {} "
2509         "after \"%s\"", name);
2510       return NULL;
2511       }
2512     sub[i] = expand_string_internal(s+1, TRUE, &s, yield == NULL,
2513         honour_dollar, resetok);
2514     if (sub[i] == NULL) return NULL;
2515     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2516
2517     /* Convert to numerical if required; we know that the names of all the
2518     conditions that compare numbers do not start with a letter. This just saves
2519     checking for them individually. */
2520
2521     if (!isalpha(name[0]) && yield != NULL)
2522       if (sub[i][0] == 0)
2523         {
2524         num[i] = 0;
2525         DEBUG(D_expand)
2526           debug_printf_indent("empty string cast to zero for numerical comparison\n");
2527         }
2528       else
2529         {
2530         num[i] = expanded_string_integer(sub[i], FALSE);
2531         if (expand_string_message != NULL) return NULL;
2532         }
2533     }
2534
2535   /* Result not required */
2536
2537   if (yield == NULL) return s;
2538
2539   /* Do an appropriate comparison */
2540
2541   switch(cond_type)
2542     {
2543     case ECOND_NUM_E:
2544     case ECOND_NUM_EE:
2545     tempcond = (num[0] == num[1]);
2546     break;
2547
2548     case ECOND_NUM_G:
2549     tempcond = (num[0] > num[1]);
2550     break;
2551
2552     case ECOND_NUM_GE:
2553     tempcond = (num[0] >= num[1]);
2554     break;
2555
2556     case ECOND_NUM_L:
2557     tempcond = (num[0] < num[1]);
2558     break;
2559
2560     case ECOND_NUM_LE:
2561     tempcond = (num[0] <= num[1]);
2562     break;
2563
2564     case ECOND_STR_LT:
2565     tempcond = (Ustrcmp(sub[0], sub[1]) < 0);
2566     break;
2567
2568     case ECOND_STR_LTI:
2569     tempcond = (strcmpic(sub[0], sub[1]) < 0);
2570     break;
2571
2572     case ECOND_STR_LE:
2573     tempcond = (Ustrcmp(sub[0], sub[1]) <= 0);
2574     break;
2575
2576     case ECOND_STR_LEI:
2577     tempcond = (strcmpic(sub[0], sub[1]) <= 0);
2578     break;
2579
2580     case ECOND_STR_EQ:
2581     tempcond = (Ustrcmp(sub[0], sub[1]) == 0);
2582     break;
2583
2584     case ECOND_STR_EQI:
2585     tempcond = (strcmpic(sub[0], sub[1]) == 0);
2586     break;
2587
2588     case ECOND_STR_GT:
2589     tempcond = (Ustrcmp(sub[0], sub[1]) > 0);
2590     break;
2591
2592     case ECOND_STR_GTI:
2593     tempcond = (strcmpic(sub[0], sub[1]) > 0);
2594     break;
2595
2596     case ECOND_STR_GE:
2597     tempcond = (Ustrcmp(sub[0], sub[1]) >= 0);
2598     break;
2599
2600     case ECOND_STR_GEI:
2601     tempcond = (strcmpic(sub[0], sub[1]) >= 0);
2602     break;
2603
2604     case ECOND_MATCH:   /* Regular expression match */
2605     re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
2606       NULL);
2607     if (re == NULL)
2608       {
2609       expand_string_message = string_sprintf("regular expression error in "
2610         "\"%s\": %s at offset %d", sub[1], rerror, roffset);
2611       return NULL;
2612       }
2613     tempcond = regex_match_and_setup(re, sub[0], 0, -1);
2614     break;
2615
2616     case ECOND_MATCH_ADDRESS:  /* Match in an address list */
2617     rc = match_address_list(sub[0], TRUE, FALSE, &(sub[1]), NULL, -1, 0, NULL);
2618     goto MATCHED_SOMETHING;
2619
2620     case ECOND_MATCH_DOMAIN:   /* Match in a domain list */
2621     rc = match_isinlist(sub[0], &(sub[1]), 0, &domainlist_anchor, NULL,
2622       MCL_DOMAIN + MCL_NOEXPAND, TRUE, NULL);
2623     goto MATCHED_SOMETHING;
2624
2625     case ECOND_MATCH_IP:       /* Match IP address in a host list */
2626     if (sub[0][0] != 0 && string_is_ip_address(sub[0], NULL) == 0)
2627       {
2628       expand_string_message = string_sprintf("\"%s\" is not an IP address",
2629         sub[0]);
2630       return NULL;
2631       }
2632     else
2633       {
2634       unsigned int *nullcache = NULL;
2635       check_host_block cb;
2636
2637       cb.host_name = US"";
2638       cb.host_address = sub[0];
2639
2640       /* If the host address starts off ::ffff: it is an IPv6 address in
2641       IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2642       addresses. */
2643
2644       cb.host_ipv4 = (Ustrncmp(cb.host_address, "::ffff:", 7) == 0)?
2645         cb.host_address + 7 : cb.host_address;
2646
2647       rc = match_check_list(
2648              &sub[1],                   /* the list */
2649              0,                         /* separator character */
2650              &hostlist_anchor,          /* anchor pointer */
2651              &nullcache,                /* cache pointer */
2652              check_host,                /* function for testing */
2653              &cb,                       /* argument for function */
2654              MCL_HOST,                  /* type of check */
2655              sub[0],                    /* text for debugging */
2656              NULL);                     /* where to pass back data */
2657       }
2658     goto MATCHED_SOMETHING;
2659
2660     case ECOND_MATCH_LOCAL_PART:
2661     rc = match_isinlist(sub[0], &(sub[1]), 0, &localpartlist_anchor, NULL,
2662       MCL_LOCALPART + MCL_NOEXPAND, TRUE, NULL);
2663     /* Fall through */
2664     /* VVVVVVVVVVVV */
2665     MATCHED_SOMETHING:
2666     switch(rc)
2667       {
2668       case OK:
2669       tempcond = TRUE;
2670       break;
2671
2672       case FAIL:
2673       tempcond = FALSE;
2674       break;
2675
2676       case DEFER:
2677       expand_string_message = string_sprintf("unable to complete match "
2678         "against \"%s\": %s", sub[1], search_error_message);
2679       return NULL;
2680       }
2681
2682     break;
2683
2684     /* Various "encrypted" comparisons. If the second string starts with
2685     "{" then an encryption type is given. Default to crypt() or crypt16()
2686     (build-time choice). */
2687     /* }-for-text-editors */
2688
2689     case ECOND_CRYPTEQ:
2690     #ifndef SUPPORT_CRYPTEQ
2691     goto COND_FAILED_NOT_COMPILED;
2692     #else
2693     if (strncmpic(sub[1], US"{md5}", 5) == 0)
2694       {
2695       int sublen = Ustrlen(sub[1]+5);
2696       md5 base;
2697       uschar digest[16];
2698
2699       md5_start(&base);
2700       md5_end(&base, sub[0], Ustrlen(sub[0]), digest);
2701
2702       /* If the length that we are comparing against is 24, the MD5 digest
2703       is expressed as a base64 string. This is the way LDAP does it. However,
2704       some other software uses a straightforward hex representation. We assume
2705       this if the length is 32. Other lengths fail. */
2706
2707       if (sublen == 24)
2708         {
2709         uschar *coded = b64encode(digest, 16);
2710         DEBUG(D_auth) debug_printf("crypteq: using MD5+B64 hashing\n"
2711           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2712         tempcond = (Ustrcmp(coded, sub[1]+5) == 0);
2713         }
2714       else if (sublen == 32)
2715         {
2716         int i;
2717         uschar coded[36];
2718         for (i = 0; i < 16; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2719         coded[32] = 0;
2720         DEBUG(D_auth) debug_printf("crypteq: using MD5+hex hashing\n"
2721           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2722         tempcond = (strcmpic(coded, sub[1]+5) == 0);
2723         }
2724       else
2725         {
2726         DEBUG(D_auth) debug_printf("crypteq: length for MD5 not 24 or 32: "
2727           "fail\n  crypted=%s\n", sub[1]+5);
2728         tempcond = FALSE;
2729         }
2730       }
2731
2732     else if (strncmpic(sub[1], US"{sha1}", 6) == 0)
2733       {
2734       int sublen = Ustrlen(sub[1]+6);
2735       hctx h;
2736       uschar digest[20];
2737
2738       sha1_start(&h);
2739       sha1_end(&h, sub[0], Ustrlen(sub[0]), digest);
2740
2741       /* If the length that we are comparing against is 28, assume the SHA1
2742       digest is expressed as a base64 string. If the length is 40, assume a
2743       straightforward hex representation. Other lengths fail. */
2744
2745       if (sublen == 28)
2746         {
2747         uschar *coded = b64encode(digest, 20);
2748         DEBUG(D_auth) debug_printf("crypteq: using SHA1+B64 hashing\n"
2749           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2750         tempcond = (Ustrcmp(coded, sub[1]+6) == 0);
2751         }
2752       else if (sublen == 40)
2753         {
2754         int i;
2755         uschar coded[44];
2756         for (i = 0; i < 20; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2757         coded[40] = 0;
2758         DEBUG(D_auth) debug_printf("crypteq: using SHA1+hex hashing\n"
2759           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2760         tempcond = (strcmpic(coded, sub[1]+6) == 0);
2761         }
2762       else
2763         {
2764         DEBUG(D_auth) debug_printf("crypteq: length for SHA-1 not 28 or 40: "
2765           "fail\n  crypted=%s\n", sub[1]+6);
2766         tempcond = FALSE;
2767         }
2768       }
2769
2770     else   /* {crypt} or {crypt16} and non-{ at start */
2771            /* }-for-text-editors */
2772       {
2773       int which = 0;
2774       uschar *coded;
2775
2776       if (strncmpic(sub[1], US"{crypt}", 7) == 0)
2777         {
2778         sub[1] += 7;
2779         which = 1;
2780         }
2781       else if (strncmpic(sub[1], US"{crypt16}", 9) == 0)
2782         {
2783         sub[1] += 9;
2784         which = 2;
2785         }
2786       else if (sub[1][0] == '{')                /* }-for-text-editors */
2787         {
2788         expand_string_message = string_sprintf("unknown encryption mechanism "
2789           "in \"%s\"", sub[1]);
2790         return NULL;
2791         }
2792
2793       switch(which)
2794         {
2795         case 0:  coded = US DEFAULT_CRYPT(CS sub[0], CS sub[1]); break;
2796         case 1:  coded = US crypt(CS sub[0], CS sub[1]); break;
2797         default: coded = US crypt16(CS sub[0], CS sub[1]); break;
2798         }
2799
2800       #define STR(s) # s
2801       #define XSTR(s) STR(s)
2802       DEBUG(D_auth) debug_printf("crypteq: using %s()\n"
2803         "  subject=%s\n  crypted=%s\n",
2804         which == 0 ? XSTR(DEFAULT_CRYPT) : which == 1 ? "crypt" : "crypt16",
2805         coded, sub[1]);
2806       #undef STR
2807       #undef XSTR
2808
2809       /* If the encrypted string contains fewer than two characters (for the
2810       salt), force failure. Otherwise we get false positives: with an empty
2811       string the yield of crypt() is an empty string! */
2812
2813       if (coded)
2814         tempcond = Ustrlen(sub[1]) < 2 ? FALSE : Ustrcmp(coded, sub[1]) == 0;
2815       else if (errno == EINVAL)
2816         tempcond = FALSE;
2817       else
2818         {
2819         expand_string_message = string_sprintf("crypt error: %s\n",
2820           US strerror(errno));
2821         return NULL;
2822         }
2823       }
2824     break;
2825     #endif  /* SUPPORT_CRYPTEQ */
2826
2827     case ECOND_INLIST:
2828     case ECOND_INLISTI:
2829       {
2830       const uschar * list = sub[1];
2831       int sep = 0;
2832       uschar *save_iterate_item = iterate_item;
2833       int (*compare)(const uschar *, const uschar *);
2834
2835       DEBUG(D_expand) debug_printf_indent("condition: %s\n", name);
2836
2837       tempcond = FALSE;
2838       compare = cond_type == ECOND_INLISTI
2839         ? strcmpic : (int (*)(const uschar *, const uschar *)) strcmp;
2840
2841       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)))
2842         if (compare(sub[0], iterate_item) == 0)
2843           {
2844           tempcond = TRUE;
2845           break;
2846           }
2847       iterate_item = save_iterate_item;
2848       }
2849
2850     }   /* Switch for comparison conditions */
2851
2852   *yield = tempcond == testfor;
2853   return s;    /* End of comparison conditions */
2854
2855
2856   /* and/or: computes logical and/or of several conditions */
2857
2858   case ECOND_AND:
2859   case ECOND_OR:
2860   subcondptr = (yield == NULL)? NULL : &tempcond;
2861   combined_cond = (cond_type == ECOND_AND);
2862
2863   while (isspace(*s)) s++;
2864   if (*s++ != '{') goto COND_FAILED_CURLY_START;        /* }-for-text-editors */
2865
2866   for (;;)
2867     {
2868     while (isspace(*s)) s++;
2869     /* {-for-text-editors */
2870     if (*s == '}') break;
2871     if (*s != '{')                                      /* }-for-text-editors */
2872       {
2873       expand_string_message = string_sprintf("each subcondition "
2874         "inside an \"%s{...}\" condition must be in its own {}", name);
2875       return NULL;
2876       }
2877
2878     if (!(s = eval_condition(s+1, resetok, subcondptr)))
2879       {
2880       expand_string_message = string_sprintf("%s inside \"%s{...}\" condition",
2881         expand_string_message, name);
2882       return NULL;
2883       }
2884     while (isspace(*s)) s++;
2885
2886     /* {-for-text-editors */
2887     if (*s++ != '}')
2888       {
2889       /* {-for-text-editors */
2890       expand_string_message = string_sprintf("missing } at end of condition "
2891         "inside \"%s\" group", name);
2892       return NULL;
2893       }
2894
2895     if (yield != NULL)
2896       {
2897       if (cond_type == ECOND_AND)
2898         {
2899         combined_cond &= tempcond;
2900         if (!combined_cond) subcondptr = NULL;  /* once false, don't */
2901         }                                       /* evaluate any more */
2902       else
2903         {
2904         combined_cond |= tempcond;
2905         if (combined_cond) subcondptr = NULL;   /* once true, don't */
2906         }                                       /* evaluate any more */
2907       }
2908     }
2909
2910   if (yield != NULL) *yield = (combined_cond == testfor);
2911   return ++s;
2912
2913
2914   /* forall/forany: iterates a condition with different values */
2915
2916   case ECOND_FORALL:
2917   case ECOND_FORANY:
2918     {
2919     const uschar * list;
2920     int sep = 0;
2921     uschar *save_iterate_item = iterate_item;
2922
2923     DEBUG(D_expand) debug_printf_indent("condition: %s\n", name);
2924
2925     while (isspace(*s)) s++;
2926     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2927     sub[0] = expand_string_internal(s, TRUE, &s, (yield == NULL), TRUE, resetok);
2928     if (sub[0] == NULL) return NULL;
2929     /* {-for-text-editors */
2930     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2931
2932     while (isspace(*s)) s++;
2933     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2934
2935     sub[1] = s;
2936
2937     /* Call eval_condition once, with result discarded (as if scanning a
2938     "false" part). This allows us to find the end of the condition, because if
2939     the list it empty, we won't actually evaluate the condition for real. */
2940
2941     if (!(s = eval_condition(sub[1], resetok, NULL)))
2942       {
2943       expand_string_message = string_sprintf("%s inside \"%s\" condition",
2944         expand_string_message, name);
2945       return NULL;
2946       }
2947     while (isspace(*s)) s++;
2948
2949     /* {-for-text-editors */
2950     if (*s++ != '}')
2951       {
2952       /* {-for-text-editors */
2953       expand_string_message = string_sprintf("missing } at end of condition "
2954         "inside \"%s\"", name);
2955       return NULL;
2956       }
2957
2958     if (yield != NULL) *yield = !testfor;
2959     list = sub[0];
2960     while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
2961       {
2962       DEBUG(D_expand) debug_printf_indent("%s: $item = \"%s\"\n", name, iterate_item);
2963       if (!eval_condition(sub[1], resetok, &tempcond))
2964         {
2965         expand_string_message = string_sprintf("%s inside \"%s\" condition",
2966           expand_string_message, name);
2967         iterate_item = save_iterate_item;
2968         return NULL;
2969         }
2970       DEBUG(D_expand) debug_printf_indent("%s: condition evaluated to %s\n", name,
2971         tempcond? "true":"false");
2972
2973       if (yield != NULL) *yield = (tempcond == testfor);
2974       if (tempcond == (cond_type == ECOND_FORANY)) break;
2975       }
2976
2977     iterate_item = save_iterate_item;
2978     return s;
2979     }
2980
2981
2982   /* The bool{} expansion condition maps a string to boolean.
2983   The values supported should match those supported by the ACL condition
2984   (acl.c, ACLC_CONDITION) so that we keep to a minimum the different ideas
2985   of true/false.  Note that Router "condition" rules have a different
2986   interpretation, where general data can be used and only a few values
2987   map to FALSE.
2988   Note that readconf.c boolean matching, for boolean configuration options,
2989   only matches true/yes/false/no.
2990   The bool_lax{} condition matches the Router logic, which is much more
2991   liberal. */
2992   case ECOND_BOOL:
2993   case ECOND_BOOL_LAX:
2994     {
2995     uschar *sub_arg[1];
2996     uschar *t, *t2;
2997     uschar *ourname;
2998     size_t len;
2999     BOOL boolvalue = FALSE;
3000     while (isspace(*s)) s++;
3001     if (*s != '{') goto COND_FAILED_CURLY_START;        /* }-for-text-editors */
3002     ourname = cond_type == ECOND_BOOL_LAX ? US"bool_lax" : US"bool";
3003     switch(read_subs(sub_arg, 1, 1, &s, yield == NULL, FALSE, ourname, resetok))
3004       {
3005       case 1: expand_string_message = string_sprintf(
3006                   "too few arguments or bracketing error for %s",
3007                   ourname);
3008       /*FALLTHROUGH*/
3009       case 2:
3010       case 3: return NULL;
3011       }
3012     t = sub_arg[0];
3013     while (isspace(*t)) t++;
3014     len = Ustrlen(t);
3015     if (len)
3016       {
3017       /* trailing whitespace: seems like a good idea to ignore it too */
3018       t2 = t + len - 1;
3019       while (isspace(*t2)) t2--;
3020       if (t2 != (t + len))
3021         {
3022         *++t2 = '\0';
3023         len = t2 - t;
3024         }
3025       }
3026     DEBUG(D_expand)
3027       debug_printf_indent("considering %s: %s\n", ourname, len ? t : US"<empty>");
3028     /* logic for the lax case from expand_check_condition(), which also does
3029     expands, and the logic is both short and stable enough that there should
3030     be no maintenance burden from replicating it. */
3031     if (len == 0)
3032       boolvalue = FALSE;
3033     else if (*t == '-'
3034              ? Ustrspn(t+1, "0123456789") == len-1
3035              : Ustrspn(t,   "0123456789") == len)
3036       {
3037       boolvalue = (Uatoi(t) == 0) ? FALSE : TRUE;
3038       /* expand_check_condition only does a literal string "0" check */
3039       if ((cond_type == ECOND_BOOL_LAX) && (len > 1))
3040         boolvalue = TRUE;
3041       }
3042     else if (strcmpic(t, US"true") == 0 || strcmpic(t, US"yes") == 0)
3043       boolvalue = TRUE;
3044     else if (strcmpic(t, US"false") == 0 || strcmpic(t, US"no") == 0)
3045       boolvalue = FALSE;
3046     else if (cond_type == ECOND_BOOL_LAX)
3047       boolvalue = TRUE;
3048     else
3049       {
3050       expand_string_message = string_sprintf("unrecognised boolean "
3051        "value \"%s\"", t);
3052       return NULL;
3053       }
3054     DEBUG(D_expand) debug_printf_indent("%s: condition evaluated to %s\n", ourname,
3055         boolvalue? "true":"false");
3056     if (yield != NULL) *yield = (boolvalue == testfor);
3057     return s;
3058     }
3059
3060   /* Unknown condition */
3061
3062   default:
3063   expand_string_message = string_sprintf("unknown condition \"%s\"", name);
3064   return NULL;
3065   }   /* End switch on condition type */
3066
3067 /* Missing braces at start and end of data */
3068
3069 COND_FAILED_CURLY_START:
3070 expand_string_message = string_sprintf("missing { after \"%s\"", name);
3071 return NULL;
3072
3073 COND_FAILED_CURLY_END:
3074 expand_string_message = string_sprintf("missing } at end of \"%s\" condition",
3075   name);
3076 return NULL;
3077
3078 /* A condition requires code that is not compiled */
3079
3080 #if !defined(SUPPORT_PAM) || !defined(RADIUS_CONFIG_FILE) || \
3081     !defined(LOOKUP_LDAP) || !defined(CYRUS_PWCHECK_SOCKET) || \
3082     !defined(SUPPORT_CRYPTEQ) || !defined(CYRUS_SASLAUTHD_SOCKET)
3083 COND_FAILED_NOT_COMPILED:
3084 expand_string_message = string_sprintf("support for \"%s\" not compiled",
3085   name);
3086 return NULL;
3087 #endif
3088 }
3089
3090
3091
3092
3093 /*************************************************
3094 *          Save numerical variables              *
3095 *************************************************/
3096
3097 /* This function is called from items such as "if" that want to preserve and
3098 restore the numbered variables.
3099
3100 Arguments:
3101   save_expand_string    points to an array of pointers to set
3102   save_expand_nlength   points to an array of ints for the lengths
3103
3104 Returns:                the value of expand max to save
3105 */
3106
3107 static int
3108 save_expand_strings(uschar **save_expand_nstring, int *save_expand_nlength)
3109 {
3110 int i;
3111 for (i = 0; i <= expand_nmax; i++)
3112   {
3113   save_expand_nstring[i] = expand_nstring[i];
3114   save_expand_nlength[i] = expand_nlength[i];
3115   }
3116 return expand_nmax;
3117 }
3118
3119
3120
3121 /*************************************************
3122 *           Restore numerical variables          *
3123 *************************************************/
3124
3125 /* This function restored saved values of numerical strings.
3126
3127 Arguments:
3128   save_expand_nmax      the number of strings to restore
3129   save_expand_string    points to an array of pointers
3130   save_expand_nlength   points to an array of ints
3131
3132 Returns:                nothing
3133 */
3134
3135 static void
3136 restore_expand_strings(int save_expand_nmax, uschar **save_expand_nstring,
3137   int *save_expand_nlength)
3138 {
3139 int i;
3140 expand_nmax = save_expand_nmax;
3141 for (i = 0; i <= expand_nmax; i++)
3142   {
3143   expand_nstring[i] = save_expand_nstring[i];
3144   expand_nlength[i] = save_expand_nlength[i];
3145   }
3146 }
3147
3148
3149
3150
3151
3152 /*************************************************
3153 *            Handle yes/no substrings            *
3154 *************************************************/
3155
3156 /* This function is used by ${if}, ${lookup} and ${extract} to handle the
3157 alternative substrings that depend on whether or not the condition was true,
3158 or the lookup or extraction succeeded. The substrings always have to be
3159 expanded, to check their syntax, but "skipping" is set when the result is not
3160 needed - this avoids unnecessary nested lookups.
3161
3162 Arguments:
3163   skipping       TRUE if we were skipping when this item was reached
3164   yes            TRUE if the first string is to be used, else use the second
3165   save_lookup    a value to put back into lookup_value before the 2nd expansion
3166   sptr           points to the input string pointer
3167   yieldptr       points to the output string pointer
3168   sizeptr        points to the output string size
3169   ptrptr         points to the output string pointer
3170   type           "lookup", "if", "extract", "run", "env", "listextract" or
3171                  "certextract" for error message
3172   resetok        if not NULL, pointer to flag - write FALSE if unsafe to reset
3173                 the store.
3174
3175 Returns:         0 OK; lookup_value has been reset to save_lookup
3176                  1 expansion failed
3177                  2 expansion failed because of bracketing error
3178 */
3179
3180 static int
3181 process_yesno(BOOL skipping, BOOL yes, uschar *save_lookup, const uschar **sptr,
3182   uschar **yieldptr, int *sizeptr, int *ptrptr, uschar *type, BOOL *resetok)
3183 {
3184 int rc = 0;
3185 const uschar *s = *sptr;    /* Local value */
3186 uschar *sub1, *sub2;
3187 const uschar * errwhere;
3188
3189 /* If there are no following strings, we substitute the contents of $value for
3190 lookups and for extractions in the success case. For the ${if item, the string
3191 "true" is substituted. In the fail case, nothing is substituted for all three
3192 items. */
3193
3194 while (isspace(*s)) s++;
3195 if (*s == '}')
3196   {
3197   if (type[0] == 'i')
3198     {
3199     if (yes && !skipping)
3200       *yieldptr = string_catn(*yieldptr, sizeptr, ptrptr, US"true", 4);
3201     }
3202   else
3203     {
3204     if (yes && lookup_value && !skipping)
3205       *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, lookup_value);
3206     lookup_value = save_lookup;
3207     }
3208   s++;
3209   goto RETURN;
3210   }
3211
3212 /* The first following string must be braced. */
3213
3214 if (*s++ != '{')
3215   {
3216   errwhere = US"'yes' part did not start with '{'";
3217   goto FAILED_CURLY;
3218   }
3219
3220 /* Expand the first substring. Forced failures are noticed only if we actually
3221 want this string. Set skipping in the call in the fail case (this will always
3222 be the case if we were already skipping). */
3223
3224 sub1 = expand_string_internal(s, TRUE, &s, !yes, TRUE, resetok);
3225 if (sub1 == NULL && (yes || !expand_string_forcedfail)) goto FAILED;
3226 expand_string_forcedfail = FALSE;
3227 if (*s++ != '}')
3228   {
3229   errwhere = US"'yes' part did not end with '}'";
3230   goto FAILED_CURLY;
3231   }
3232
3233 /* If we want the first string, add it to the output */
3234
3235 if (yes)
3236   *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub1);
3237
3238 /* If this is called from a lookup/env or a (cert)extract, we want to restore
3239 $value to what it was at the start of the item, so that it has this value
3240 during the second string expansion. For the call from "if" or "run" to this
3241 function, save_lookup is set to lookup_value, so that this statement does
3242 nothing. */
3243
3244 lookup_value = save_lookup;
3245
3246 /* There now follows either another substring, or "fail", or nothing. This
3247 time, forced failures are noticed only if we want the second string. We must
3248 set skipping in the nested call if we don't want this string, or if we were
3249 already skipping. */
3250
3251 while (isspace(*s)) s++;
3252 if (*s == '{')
3253   {
3254   sub2 = expand_string_internal(s+1, TRUE, &s, yes || skipping, TRUE, resetok);
3255   if (sub2 == NULL && (!yes || !expand_string_forcedfail)) goto FAILED;
3256   expand_string_forcedfail = FALSE;
3257   if (*s++ != '}')
3258     {
3259     errwhere = US"'no' part did not start with '{'";
3260     goto FAILED_CURLY;
3261     }
3262
3263   /* If we want the second string, add it to the output */
3264
3265   if (!yes)
3266     *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub2);
3267   }
3268
3269 /* If there is no second string, but the word "fail" is present when the use of
3270 the second string is wanted, set a flag indicating it was a forced failure
3271 rather than a syntactic error. Swallow the terminating } in case this is nested
3272 inside another lookup or if or extract. */
3273
3274 else if (*s != '}')
3275   {
3276   uschar name[256];
3277   /* deconst cast ok here as source is s anyway */
3278   s = US read_name(name, sizeof(name), s, US"_");
3279   if (Ustrcmp(name, "fail") == 0)
3280     {
3281     if (!yes && !skipping)
3282       {
3283       while (isspace(*s)) s++;
3284       if (*s++ != '}')
3285         {
3286         errwhere = US"did not close with '}' after forcedfail";
3287         goto FAILED_CURLY;
3288         }
3289       expand_string_message =
3290         string_sprintf("\"%s\" failed and \"fail\" requested", type);
3291       expand_string_forcedfail = TRUE;
3292       goto FAILED;
3293       }
3294     }
3295   else
3296     {
3297     expand_string_message =
3298       string_sprintf("syntax error in \"%s\" item - \"fail\" expected", type);
3299     goto FAILED;
3300     }
3301   }
3302
3303 /* All we have to do now is to check on the final closing brace. */
3304
3305 while (isspace(*s)) s++;
3306 if (*s++ != '}')
3307   {
3308   errwhere = US"did not close with '}'";
3309   goto FAILED_CURLY;
3310   }
3311
3312
3313 RETURN:
3314 /* Update the input pointer value before returning */
3315 *sptr = s;
3316 return rc;
3317
3318 FAILED_CURLY:
3319   /* Get here if there is a bracketing failure */
3320   expand_string_message = string_sprintf(
3321     "curly-bracket problem in conditional yes/no parsing: %s\n"
3322     " remaining string is '%s'", errwhere, --s);
3323   rc = 2;
3324   goto RETURN;
3325
3326 FAILED:
3327   /* Get here for other failures */
3328   rc = 1;
3329   goto RETURN;
3330 }
3331
3332
3333
3334
3335 /*************************************************
3336 *    Handle MD5 or SHA-1 computation for HMAC    *
3337 *************************************************/
3338
3339 /* These are some wrapping functions that enable the HMAC code to be a bit
3340 cleaner. A good compiler will spot the tail recursion.
3341
3342 Arguments:
3343   type         HMAC_MD5 or HMAC_SHA1
3344   remaining    are as for the cryptographic hash functions
3345
3346 Returns:       nothing
3347 */
3348
3349 static void
3350 chash_start(int type, void *base)
3351 {
3352 if (type == HMAC_MD5)
3353   md5_start((md5 *)base);
3354 else
3355   sha1_start((hctx *)base);
3356 }
3357
3358 static void
3359 chash_mid(int type, void *base, uschar *string)
3360 {
3361 if (type == HMAC_MD5)
3362   md5_mid((md5 *)base, string);
3363 else
3364   sha1_mid((hctx *)base, string);
3365 }
3366
3367 static void
3368 chash_end(int type, void *base, uschar *string, int length, uschar *digest)
3369 {
3370 if (type == HMAC_MD5)
3371   md5_end((md5 *)base, string, length, digest);
3372 else
3373   sha1_end((hctx *)base, string, length, digest);
3374 }
3375
3376
3377
3378
3379
3380 /********************************************************
3381 * prvs: Get last three digits of days since Jan 1, 1970 *
3382 ********************************************************/
3383
3384 /* This is needed to implement the "prvs" BATV reverse
3385    path signing scheme
3386
3387 Argument: integer "days" offset to add or substract to
3388           or from the current number of days.
3389
3390 Returns:  pointer to string containing the last three
3391           digits of the number of days since Jan 1, 1970,
3392           modified by the offset argument, NULL if there
3393           was an error in the conversion.
3394
3395 */
3396
3397 static uschar *
3398 prvs_daystamp(int day_offset)
3399 {
3400 uschar *days = store_get(32);                /* Need at least 24 for cases */
3401 (void)string_format(days, 32, TIME_T_FMT,    /* where TIME_T_FMT is %lld */
3402   (time(NULL) + day_offset*86400)/86400);
3403 return (Ustrlen(days) >= 3) ? &days[Ustrlen(days)-3] : US"100";
3404 }
3405
3406
3407
3408 /********************************************************
3409 *   prvs: perform HMAC-SHA1 computation of prvs bits    *
3410 ********************************************************/
3411
3412 /* This is needed to implement the "prvs" BATV reverse
3413    path signing scheme
3414
3415 Arguments:
3416   address RFC2821 Address to use
3417       key The key to use (must be less than 64 characters
3418           in size)
3419   key_num Single-digit key number to use. Defaults to
3420           '0' when NULL.
3421
3422 Returns:  pointer to string containing the first three
3423           bytes of the final hash in hex format, NULL if
3424           there was an error in the process.
3425 */
3426
3427 static uschar *
3428 prvs_hmac_sha1(uschar *address, uschar *key, uschar *key_num, uschar *daystamp)
3429 {
3430 uschar *hash_source, *p;
3431 int size = 0,offset = 0,i;
3432 hctx h;
3433 uschar innerhash[20];
3434 uschar finalhash[20];
3435 uschar innerkey[64];
3436 uschar outerkey[64];
3437 uschar *finalhash_hex = store_get(40);
3438
3439 if (key_num == NULL)
3440   key_num = US"0";
3441
3442 if (Ustrlen(key) > 64)
3443   return NULL;
3444
3445 hash_source = string_catn(NULL, &size, &offset, key_num, 1);
3446 hash_source = string_catn(hash_source, &size, &offset, daystamp, 3);
3447 hash_source = string_cat(hash_source, &size, &offset, address);
3448 hash_source[offset] = '\0';
3449
3450 DEBUG(D_expand) debug_printf_indent("prvs: hash source is '%s'\n", hash_source);
3451
3452 memset(innerkey, 0x36, 64);
3453 memset(outerkey, 0x5c, 64);
3454
3455 for (i = 0; i < Ustrlen(key); i++)
3456   {
3457   innerkey[i] ^= key[i];
3458   outerkey[i] ^= key[i];
3459   }
3460
3461 chash_start(HMAC_SHA1, &h);
3462 chash_mid(HMAC_SHA1, &h, innerkey);
3463 chash_end(HMAC_SHA1, &h, hash_source, offset, innerhash);
3464
3465 chash_start(HMAC_SHA1, &h);
3466 chash_mid(HMAC_SHA1, &h, outerkey);
3467 chash_end(HMAC_SHA1, &h, innerhash, 20, finalhash);
3468
3469 p = finalhash_hex;
3470 for (i = 0; i < 3; i++)
3471   {
3472   *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
3473   *p++ = hex_digits[finalhash[i] & 0x0f];
3474   }
3475 *p = '\0';
3476
3477 return finalhash_hex;
3478 }
3479
3480
3481
3482
3483 /*************************************************
3484 *        Join a file onto the output string      *
3485 *************************************************/
3486
3487 /* This is used for readfile/readsock and after a run expansion.
3488 It joins the contents of a file onto the output string, globally replacing
3489 newlines with a given string (optionally).
3490
3491 Arguments:
3492   f            the FILE
3493   yield        pointer to the expandable string
3494   sizep        pointer to the current size
3495   ptrp         pointer to the current position
3496   eol          newline replacement string, or NULL
3497
3498 Returns:       new value of string pointer
3499 */
3500
3501 static uschar *
3502 cat_file(FILE *f, uschar *yield, int *sizep, int *ptrp, uschar *eol)
3503 {
3504 uschar buffer[1024];
3505
3506 while (Ufgets(buffer, sizeof(buffer), f))
3507   {
3508   int len = Ustrlen(buffer);
3509   if (eol && buffer[len-1] == '\n') len--;
3510   yield = string_catn(yield, sizep, ptrp, buffer, len);
3511   if (eol && buffer[len])
3512     yield = string_cat(yield, sizep, ptrp, eol);
3513   }
3514
3515 if (yield) yield[*ptrp] = 0;
3516
3517 return yield;
3518 }
3519
3520
3521
3522
3523 /*************************************************
3524 *          Evaluate numeric expression           *
3525 *************************************************/
3526
3527 /* This is a set of mutually recursive functions that evaluate an arithmetic
3528 expression involving + - * / % & | ^ ~ << >> and parentheses. The only one of
3529 these functions that is called from elsewhere is eval_expr, whose interface is:
3530
3531 Arguments:
3532   sptr        pointer to the pointer to the string - gets updated
3533   decimal     TRUE if numbers are to be assumed decimal
3534   error       pointer to where to put an error message - must be NULL on input
3535   endket      TRUE if ')' must terminate - FALSE for external call
3536
3537 Returns:      on success: the value of the expression, with *error still NULL
3538               on failure: an undefined value, with *error = a message
3539 */
3540
3541 static int_eximarith_t eval_op_or(uschar **, BOOL, uschar **);
3542
3543
3544 static int_eximarith_t
3545 eval_expr(uschar **sptr, BOOL decimal, uschar **error, BOOL endket)
3546 {
3547 uschar *s = *sptr;
3548 int_eximarith_t x = eval_op_or(&s, decimal, error);
3549 if (*error == NULL)
3550   {
3551   if (endket)
3552     {
3553     if (*s != ')')
3554       *error = US"expecting closing parenthesis";
3555     else
3556       while (isspace(*(++s)));
3557     }
3558   else if (*s != 0) *error = US"expecting operator";
3559   }
3560 *sptr = s;
3561 return x;
3562 }
3563
3564
3565 static int_eximarith_t
3566 eval_number(uschar **sptr, BOOL decimal, uschar **error)
3567 {
3568 register int c;
3569 int_eximarith_t n;
3570 uschar *s = *sptr;
3571 while (isspace(*s)) s++;
3572 c = *s;
3573 if (isdigit(c))
3574   {
3575   int count;
3576   (void)sscanf(CS s, (decimal? SC_EXIM_DEC "%n" : SC_EXIM_ARITH "%n"), &n, &count);
3577   s += count;
3578   switch (tolower(*s))
3579     {
3580     default: break;
3581     case 'k': n *= 1024; s++; break;
3582     case 'm': n *= 1024*1024; s++; break;
3583     case 'g': n *= 1024*1024*1024; s++; break;
3584     }
3585   while (isspace (*s)) s++;
3586   }
3587 else if (c == '(')
3588   {
3589   s++;
3590   n = eval_expr(&s, decimal, error, 1);
3591   }
3592 else
3593   {
3594   *error = US"expecting number or opening parenthesis";
3595   n = 0;
3596   }
3597 *sptr = s;
3598 return n;
3599 }
3600
3601
3602 static int_eximarith_t
3603 eval_op_unary(uschar **sptr, BOOL decimal, uschar **error)
3604 {
3605 uschar *s = *sptr;
3606 int_eximarith_t x;
3607 while (isspace(*s)) s++;
3608 if (*s == '+' || *s == '-' || *s == '~')
3609   {
3610   int op = *s++;
3611   x = eval_op_unary(&s, decimal, error);
3612   if (op == '-') x = -x;
3613     else if (op == '~') x = ~x;
3614   }
3615 else
3616   {
3617   x = eval_number(&s, decimal, error);
3618   }
3619 *sptr = s;
3620 return x;
3621 }
3622
3623
3624 static int_eximarith_t
3625 eval_op_mult(uschar **sptr, BOOL decimal, uschar **error)
3626 {
3627 uschar *s = *sptr;
3628 int_eximarith_t x = eval_op_unary(&s, decimal, error);
3629 if (*error == NULL)
3630   {
3631   while (*s == '*' || *s == '/' || *s == '%')
3632     {
3633     int op = *s++;
3634     int_eximarith_t y = eval_op_unary(&s, decimal, error);
3635     if (*error != NULL) break;
3636     /* SIGFPE both on div/mod by zero and on INT_MIN / -1, which would give
3637      * a value of INT_MAX+1. Note that INT_MIN * -1 gives INT_MIN for me, which
3638      * is a bug somewhere in [gcc 4.2.1, FreeBSD, amd64].  In fact, -N*-M where
3639      * -N*M is INT_MIN will yield INT_MIN.
3640      * Since we don't support floating point, this is somewhat simpler.
3641      * Ideally, we'd return an error, but since we overflow for all other
3642      * arithmetic, consistency suggests otherwise, but what's the correct value
3643      * to use?  There is none.
3644      * The C standard guarantees overflow for unsigned arithmetic but signed
3645      * overflow invokes undefined behaviour; in practice, this is overflow
3646      * except for converting INT_MIN to INT_MAX+1.  We also can't guarantee
3647      * that long/longlong larger than int are available, or we could just work
3648      * with larger types.  We should consider whether to guarantee 32bit eval
3649      * and 64-bit working variables, with errors returned.  For now ...
3650      * So, the only SIGFPEs occur with a non-shrinking div/mod, thus -1; we
3651      * can just let the other invalid results occur otherwise, as they have
3652      * until now.  For this one case, we can coerce.
3653      */
3654     if (y == -1 && x == EXIM_ARITH_MIN && op != '*')
3655       {
3656       DEBUG(D_expand)
3657         debug_printf("Integer exception dodging: " PR_EXIM_ARITH "%c-1 coerced to " PR_EXIM_ARITH "\n",
3658             EXIM_ARITH_MIN, op, EXIM_ARITH_MAX);
3659       x = EXIM_ARITH_MAX;
3660       continue;
3661       }
3662     if (op == '*')
3663       x *= y;
3664     else
3665       {
3666       if (y == 0)
3667         {
3668         *error = (op == '/') ? US"divide by zero" : US"modulo by zero";
3669         x = 0;
3670         break;
3671         }
3672       if (op == '/')
3673         x /= y;
3674       else
3675         x %= y;
3676       }
3677     }
3678   }
3679 *sptr = s;
3680 return x;
3681 }
3682
3683
3684 static int_eximarith_t
3685 eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
3686 {
3687 uschar *s = *sptr;
3688 int_eximarith_t x = eval_op_mult(&s, decimal, error);
3689 if (!*error)
3690   {
3691   while (*s == '+' || *s == '-')
3692     {
3693     int op = *s++;
3694     int_eximarith_t y = eval_op_mult(&s, decimal, error);
3695     if (*error) break;
3696     if (  (x >=   EXIM_ARITH_MAX/2  && x >=   EXIM_ARITH_MAX/2)
3697        || (x <= -(EXIM_ARITH_MAX/2) && y <= -(EXIM_ARITH_MAX/2)))
3698       {                 /* over-conservative check */
3699       *error = op == '+'
3700         ? US"overflow in sum" : US"overflow in difference";
3701       break;
3702       }
3703     if (op == '+') x += y; else x -= y;
3704     }
3705   }
3706 *sptr = s;
3707 return x;
3708 }
3709
3710
3711 static int_eximarith_t
3712 eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
3713 {
3714 uschar *s = *sptr;
3715 int_eximarith_t x = eval_op_sum(&s, decimal, error);
3716 if (*error == NULL)
3717   {
3718   while ((*s == '<' || *s == '>') && s[1] == s[0])
3719     {
3720     int_eximarith_t y;
3721     int op = *s++;
3722     s++;
3723     y = eval_op_sum(&s, decimal, error);
3724     if (*error != NULL) break;
3725     if (op == '<') x <<= y; else x >>= y;
3726     }
3727   }
3728 *sptr = s;
3729 return x;
3730 }
3731
3732
3733 static int_eximarith_t
3734 eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
3735 {
3736 uschar *s = *sptr;
3737 int_eximarith_t x = eval_op_shift(&s, decimal, error);
3738 if (*error == NULL)
3739   {
3740   while (*s == '&')
3741     {
3742     int_eximarith_t y;
3743     s++;
3744     y = eval_op_shift(&s, decimal, error);
3745     if (*error != NULL) break;
3746     x &= y;
3747     }
3748   }
3749 *sptr = s;
3750 return x;
3751 }
3752
3753
3754 static int_eximarith_t
3755 eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
3756 {
3757 uschar *s = *sptr;
3758 int_eximarith_t x = eval_op_and(&s, decimal, error);
3759 if (*error == NULL)
3760   {
3761   while (*s == '^')
3762     {
3763     int_eximarith_t y;
3764     s++;
3765     y = eval_op_and(&s, decimal, error);
3766     if (*error != NULL) break;
3767     x ^= y;
3768     }
3769   }
3770 *sptr = s;
3771 return x;
3772 }
3773
3774
3775 static int_eximarith_t
3776 eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
3777 {
3778 uschar *s = *sptr;
3779 int_eximarith_t x = eval_op_xor(&s, decimal, error);
3780 if (*error == NULL)
3781   {
3782   while (*s == '|')
3783     {
3784     int_eximarith_t y;
3785     s++;
3786     y = eval_op_xor(&s, decimal, error);
3787     if (*error != NULL) break;
3788     x |= y;
3789     }
3790   }
3791 *sptr = s;
3792 return x;
3793 }
3794
3795
3796
3797 /*************************************************
3798 *                 Expand string                  *
3799 *************************************************/
3800
3801 /* Returns either an unchanged string, or the expanded string in stacking pool
3802 store. Interpreted sequences are:
3803
3804    \...                    normal escaping rules
3805    $name                   substitutes the variable
3806    ${name}                 ditto
3807    ${op:string}            operates on the expanded string value
3808    ${item{arg1}{arg2}...}  expands the args and then does the business
3809                              some literal args are not enclosed in {}
3810
3811 There are now far too many operators and item types to make it worth listing
3812 them here in detail any more.
3813
3814 We use an internal routine recursively to handle embedded substrings. The
3815 external function follows. The yield is NULL if the expansion failed, and there
3816 are two cases: if something collapsed syntactically, or if "fail" was given
3817 as the action on a lookup failure. These can be distinguished by looking at the
3818 variable expand_string_forcedfail, which is TRUE in the latter case.
3819
3820 The skipping flag is set true when expanding a substring that isn't actually
3821 going to be used (after "if" or "lookup") and it prevents lookups from
3822 happening lower down.
3823
3824 Store usage: At start, a store block of the length of the input plus 64
3825 is obtained. This is expanded as necessary by string_cat(), which might have to
3826 get a new block, or might be able to expand the original. At the end of the
3827 function we can release any store above that portion of the yield block that
3828 was actually used. In many cases this will be optimal.
3829
3830 However: if the first item in the expansion is a variable name or header name,
3831 we reset the store before processing it; if the result is in fresh store, we
3832 use that without copying. This is helpful for expanding strings like
3833 $message_headers which can get very long.
3834
3835 There's a problem if a ${dlfunc item has side-effects that cause allocation,
3836 since resetting the store at the end of the expansion will free store that was
3837 allocated by the plugin code as well as the slop after the expanded string. So
3838 we skip any resets if ${dlfunc } has been used. The same applies for ${acl }
3839 and, given the acl condition, ${if }. This is an unfortunate consequence of
3840 string expansion becoming too powerful.
3841
3842 Arguments:
3843   string         the string to be expanded
3844   ket_ends       true if expansion is to stop at }
3845   left           if not NULL, a pointer to the first character after the
3846                  expansion is placed here (typically used with ket_ends)
3847   skipping       TRUE for recursive calls when the value isn't actually going
3848                  to be used (to allow for optimisation)
3849   honour_dollar  TRUE if $ is to be expanded,
3850                  FALSE if it's just another character
3851   resetok_p      if not NULL, pointer to flag - write FALSE if unsafe to reset
3852                  the store.
3853
3854 Returns:         NULL if expansion fails:
3855                    expand_string_forcedfail is set TRUE if failure was forced
3856                    expand_string_message contains a textual error message
3857                  a pointer to the expanded string on success
3858 */
3859
3860 static uschar *
3861 expand_string_internal(const uschar *string, BOOL ket_ends, const uschar **left,
3862   BOOL skipping, BOOL honour_dollar, BOOL *resetok_p)
3863 {
3864 int ptr = 0;
3865 int size = Ustrlen(string)+ 64;
3866 uschar *yield = store_get(size);
3867 int item_type;
3868 const uschar *s = string;
3869 uschar *save_expand_nstring[EXPAND_MAXN+1];
3870 int save_expand_nlength[EXPAND_MAXN+1];
3871 BOOL resetok = TRUE;
3872
3873 expand_level++;
3874 DEBUG(D_expand)
3875   debug_printf_indent(UTF8_DOWN_RIGHT "%s: %s\n",
3876     skipping
3877     ? UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ "scanning"
3878     : "considering",
3879     string);
3880
3881 expand_string_forcedfail = FALSE;
3882 expand_string_message = US"";
3883
3884 while (*s != 0)
3885   {
3886   uschar *value;
3887   uschar name[256];
3888
3889   /* \ escapes the next character, which must exist, or else
3890   the expansion fails. There's a special escape, \N, which causes
3891   copying of the subject verbatim up to the next \N. Otherwise,
3892   the escapes are the standard set. */
3893
3894   if (*s == '\\')
3895     {
3896     if (s[1] == 0)
3897       {
3898       expand_string_message = US"\\ at end of string";
3899       goto EXPAND_FAILED;
3900       }
3901
3902     if (s[1] == 'N')
3903       {
3904       const uschar * t = s + 2;
3905       for (s = t; *s != 0; s++) if (*s == '\\' && s[1] == 'N') break;
3906       yield = string_catn(yield, &size, &ptr, t, s - t);
3907       if (*s != 0) s += 2;
3908       }
3909
3910     else
3911       {
3912       uschar ch[1];
3913       ch[0] = string_interpret_escape(&s);
3914       s++;
3915       yield = string_catn(yield, &size, &ptr, ch, 1);
3916       }
3917
3918     continue;
3919     }
3920
3921   /*{*/
3922   /* Anything other than $ is just copied verbatim, unless we are
3923   looking for a terminating } character. */
3924
3925   /*{*/
3926   if (ket_ends && *s == '}') break;
3927
3928   if (*s != '$' || !honour_dollar)
3929     {
3930     yield = string_catn(yield, &size, &ptr, s++, 1);
3931     continue;
3932     }
3933
3934   /* No { after the $ - must be a plain name or a number for string
3935   match variable. There has to be a fudge for variables that are the
3936   names of header fields preceded by "$header_" because header field
3937   names can contain any printing characters except space and colon.
3938   For those that don't like typing this much, "$h_" is a synonym for
3939   "$header_". A non-existent header yields a NULL value; nothing is
3940   inserted. */  /*}*/
3941
3942   if (isalpha((*(++s))))
3943     {
3944     int len;
3945     int newsize = 0;
3946
3947     s = read_name(name, sizeof(name), s, US"_");
3948
3949     /* If this is the first thing to be expanded, release the pre-allocated
3950     buffer. */
3951
3952     if (ptr == 0 && yield != NULL)
3953       {
3954       if (resetok) store_reset(yield);
3955       yield = NULL;
3956       size = 0;
3957       }
3958
3959     /* Header */
3960
3961     if (Ustrncmp(name, "h_", 2) == 0 ||
3962         Ustrncmp(name, "rh_", 3) == 0 ||
3963         Ustrncmp(name, "bh_", 3) == 0 ||
3964         Ustrncmp(name, "header_", 7) == 0 ||
3965         Ustrncmp(name, "rheader_", 8) == 0 ||
3966         Ustrncmp(name, "bheader_", 8) == 0)
3967       {
3968       BOOL want_raw = (name[0] == 'r')? TRUE : FALSE;
3969       uschar *charset = (name[0] == 'b')? NULL : headers_charset;
3970       s = read_header_name(name, sizeof(name), s);
3971       value = find_header(name, FALSE, &newsize, want_raw, charset);
3972
3973       /* If we didn't find the header, and the header contains a closing brace
3974       character, this may be a user error where the terminating colon
3975       has been omitted. Set a flag to adjust the error message in this case.
3976       But there is no error here - nothing gets inserted. */
3977
3978       if (value == NULL)
3979         {
3980         if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
3981         continue;
3982         }
3983       }
3984
3985     /* Variable */
3986
3987     else if (!(value = find_variable(name, FALSE, skipping, &newsize)))
3988       {
3989       expand_string_message =
3990         string_sprintf("unknown variable name \"%s\"", name);
3991         check_variable_error_message(name);
3992       goto EXPAND_FAILED;
3993       }
3994
3995     /* If the data is known to be in a new buffer, newsize will be set to the
3996     size of that buffer. If this is the first thing in an expansion string,
3997     yield will be NULL; just point it at the new store instead of copying. Many
3998     expansion strings contain just one reference, so this is a useful
3999     optimization, especially for humungous headers. */
4000
4001     len = Ustrlen(value);
4002     if (yield == NULL && newsize != 0)
4003       {
4004       yield = value;
4005       size = newsize;
4006       ptr = len;
4007       }
4008     else yield = string_catn(yield, &size, &ptr, value, len);
4009
4010     continue;
4011     }
4012
4013   if (isdigit(*s))
4014     {
4015     int n;
4016     s = read_cnumber(&n, s);
4017     if (n >= 0 && n <= expand_nmax)
4018       yield = string_catn(yield, &size, &ptr, expand_nstring[n],
4019         expand_nlength[n]);
4020     continue;
4021     }
4022
4023   /* Otherwise, if there's no '{' after $ it's an error. */             /*}*/
4024
4025   if (*s != '{')                                                        /*}*/
4026     {
4027     expand_string_message = US"$ not followed by letter, digit, or {";  /*}*/
4028     goto EXPAND_FAILED;
4029     }
4030
4031   /* After { there can be various things, but they all start with
4032   an initial word, except for a number for a string match variable. */
4033
4034   if (isdigit((*(++s))))
4035     {
4036     int n;
4037     s = read_cnumber(&n, s);            /*{*/
4038     if (*s++ != '}')
4039       {                                 /*{*/
4040       expand_string_message = US"} expected after number";
4041       goto EXPAND_FAILED;
4042       }
4043     if (n >= 0 && n <= expand_nmax)
4044       yield = string_catn(yield, &size, &ptr, expand_nstring[n],
4045         expand_nlength[n]);
4046     continue;
4047     }
4048
4049   if (!isalpha(*s))
4050     {
4051     expand_string_message = US"letter or digit expected after ${";      /*}*/
4052     goto EXPAND_FAILED;
4053     }
4054
4055   /* Allow "-" in names to cater for substrings with negative
4056   arguments. Since we are checking for known names after { this is
4057   OK. */
4058
4059   s = read_name(name, sizeof(name), s, US"_-");
4060   item_type = chop_match(name, item_table, nelem(item_table));
4061
4062   switch(item_type)
4063     {
4064     /* Call an ACL from an expansion.  We feed data in via $acl_arg1 - $acl_arg9.
4065     If the ACL returns accept or reject we return content set by "message ="
4066     There is currently no limit on recursion; this would have us call
4067     acl_check_internal() directly and get a current level from somewhere.
4068     See also the acl expansion condition ECOND_ACL and the traditional
4069     acl modifier ACLC_ACL.
4070     Assume that the function has side-effects on the store that must be preserved.
4071     */
4072
4073     case EITEM_ACL:
4074       /* ${acl {name} {arg1}{arg2}...} */
4075       {
4076       uschar *sub[10];  /* name + arg1-arg9 (which must match number of acl_arg[]) */
4077       uschar *user_msg;
4078
4079       switch(read_subs(sub, nelem(sub), 1, &s, skipping, TRUE, US"acl",
4080                       &resetok))
4081         {
4082         case 1: goto EXPAND_FAILED_CURLY;
4083         case 2:
4084         case 3: goto EXPAND_FAILED;
4085         }
4086       if (skipping) continue;
4087
4088       resetok = FALSE;
4089       switch(eval_acl(sub, nelem(sub), &user_msg))
4090         {
4091         case OK:
4092         case FAIL:
4093           DEBUG(D_expand)
4094             debug_printf_indent("acl expansion yield: %s\n", user_msg);
4095           if (user_msg)
4096             yield = string_cat(yield, &size, &ptr, user_msg);
4097           continue;
4098
4099         case DEFER:
4100           expand_string_forcedfail = TRUE;
4101           /*FALLTHROUGH*/
4102         default:
4103           expand_string_message = string_sprintf("error from acl \"%s\"", sub[0]);
4104           goto EXPAND_FAILED;
4105         }
4106       }
4107
4108     /* Handle conditionals - preserve the values of the numerical expansion
4109     variables in case they get changed by a regular expression match in the
4110     condition. If not, they retain their external settings. At the end
4111     of this "if" section, they get restored to their previous values. */
4112
4113     case EITEM_IF:
4114       {
4115       BOOL cond = FALSE;
4116       const uschar *next_s;
4117       int save_expand_nmax =
4118         save_expand_strings(save_expand_nstring, save_expand_nlength);
4119
4120       while (isspace(*s)) s++;
4121       next_s = eval_condition(s, &resetok, skipping ? NULL : &cond);
4122       if (next_s == NULL) goto EXPAND_FAILED;  /* message already set */
4123
4124       DEBUG(D_expand)
4125         {
4126         debug_printf_indent(UTF8_VERT_RIGHT UTF8_HORIZ UTF8_HORIZ
4127           "condition: %.*s\n",
4128           (int)(next_s - s), s);
4129         debug_printf_indent(UTF8_VERT_RIGHT UTF8_HORIZ UTF8_HORIZ
4130           UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ
4131           "result: %s\n",
4132           cond ? "true" : "false");
4133         }
4134
4135       s = next_s;
4136
4137       /* The handling of "yes" and "no" result strings is now in a separate
4138       function that is also used by ${lookup} and ${extract} and ${run}. */
4139
4140       switch(process_yesno(
4141                skipping,                     /* were previously skipping */
4142                cond,                         /* success/failure indicator */
4143                lookup_value,                 /* value to reset for string2 */
4144                &s,                           /* input pointer */
4145                &yield,                       /* output pointer */
4146                &size,                        /* output size */
4147                &ptr,                         /* output current point */
4148                US"if",                       /* condition type */
4149                &resetok))
4150         {
4151         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4152         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4153         }
4154
4155       /* Restore external setting of expansion variables for continuation
4156       at this level. */
4157
4158       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4159         save_expand_nlength);
4160       continue;
4161       }
4162
4163 #ifdef SUPPORT_I18N
4164     case EITEM_IMAPFOLDER:
4165       {                         /* ${imapfolder {name}{sep]{specials}} */
4166       uschar *sub_arg[3];
4167       uschar *encoded;
4168
4169       switch(read_subs(sub_arg, nelem(sub_arg), 1, &s, skipping, TRUE, name,
4170                       &resetok))
4171         {
4172         case 1: goto EXPAND_FAILED_CURLY;
4173         case 2:
4174         case 3: goto EXPAND_FAILED;
4175         }
4176
4177       if (sub_arg[1] == NULL)           /* One argument */
4178         {
4179         sub_arg[1] = US"/";             /* default separator */
4180         sub_arg[2] = NULL;
4181         }
4182       else if (Ustrlen(sub_arg[1]) != 1)
4183         {
4184         expand_string_message =
4185           string_sprintf(
4186                 "IMAP folder separator must be one character, found \"%s\"",
4187                 sub_arg[1]);
4188         goto EXPAND_FAILED;
4189         }
4190
4191       if (!skipping)
4192         {
4193         if (!(encoded = imap_utf7_encode(sub_arg[0], headers_charset,
4194                             sub_arg[1][0], sub_arg[2], &expand_string_message)))
4195           goto EXPAND_FAILED;
4196         yield = string_cat(yield, &size, &ptr, encoded);
4197         }
4198       continue;
4199       }
4200 #endif
4201
4202     /* Handle database lookups unless locked out. If "skipping" is TRUE, we are
4203     expanding an internal string that isn't actually going to be used. All we
4204     need to do is check the syntax, so don't do a lookup at all. Preserve the
4205     values of the numerical expansion variables in case they get changed by a
4206     partial lookup. If not, they retain their external settings. At the end
4207     of this "lookup" section, they get restored to their previous values. */
4208
4209     case EITEM_LOOKUP:
4210       {
4211       int stype, partial, affixlen, starflags;
4212       int expand_setup = 0;
4213       int nameptr = 0;
4214       uschar *key, *filename;
4215       const uschar *affix;
4216       uschar *save_lookup_value = lookup_value;
4217       int save_expand_nmax =
4218         save_expand_strings(save_expand_nstring, save_expand_nlength);
4219
4220       if ((expand_forbid & RDO_LOOKUP) != 0)
4221         {
4222         expand_string_message = US"lookup expansions are not permitted";
4223         goto EXPAND_FAILED;
4224         }
4225
4226       /* Get the key we are to look up for single-key+file style lookups.
4227       Otherwise set the key NULL pro-tem. */
4228
4229       while (isspace(*s)) s++;
4230       if (*s == '{')                                    /*}*/
4231         {
4232         key = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
4233         if (!key) goto EXPAND_FAILED;                   /*{{*/
4234         if (*s++ != '}')
4235           {
4236           expand_string_message = US"missing '}' after lookup key";
4237           goto EXPAND_FAILED_CURLY;
4238           }
4239         while (isspace(*s)) s++;
4240         }
4241       else key = NULL;
4242
4243       /* Find out the type of database */
4244
4245       if (!isalpha(*s))
4246         {
4247         expand_string_message = US"missing lookup type";
4248         goto EXPAND_FAILED;
4249         }
4250
4251       /* The type is a string that may contain special characters of various
4252       kinds. Allow everything except space or { to appear; the actual content
4253       is checked by search_findtype_partial. */         /*}*/
4254
4255       while (*s != 0 && *s != '{' && !isspace(*s))      /*}*/
4256         {
4257         if (nameptr < sizeof(name) - 1) name[nameptr++] = *s;
4258         s++;
4259         }
4260       name[nameptr] = 0;
4261       while (isspace(*s)) s++;
4262
4263       /* Now check for the individual search type and any partial or default
4264       options. Only those types that are actually in the binary are valid. */
4265
4266       stype = search_findtype_partial(name, &partial, &affix, &affixlen,
4267         &starflags);
4268       if (stype < 0)
4269         {
4270         expand_string_message = search_error_message;
4271         goto EXPAND_FAILED;
4272         }
4273
4274       /* Check that a key was provided for those lookup types that need it,
4275       and was not supplied for those that use the query style. */
4276
4277       if (!mac_islookup(stype, lookup_querystyle|lookup_absfilequery))
4278         {
4279         if (key == NULL)
4280           {
4281           expand_string_message = string_sprintf("missing {key} for single-"
4282             "key \"%s\" lookup", name);
4283           goto EXPAND_FAILED;
4284           }
4285         }
4286       else
4287         {
4288         if (key != NULL)
4289           {
4290           expand_string_message = string_sprintf("a single key was given for "
4291             "lookup type \"%s\", which is not a single-key lookup type", name);
4292           goto EXPAND_FAILED;
4293           }
4294         }
4295
4296       /* Get the next string in brackets and expand it. It is the file name for
4297       single-key+file lookups, and the whole query otherwise. In the case of
4298       queries that also require a file name (e.g. sqlite), the file name comes
4299       first. */
4300
4301       if (*s != '{')
4302         {
4303         expand_string_message = US"missing '{' for lookup file-or-query arg";
4304         goto EXPAND_FAILED_CURLY;
4305         }
4306       filename = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
4307       if (filename == NULL) goto EXPAND_FAILED;
4308       if (*s++ != '}')
4309         {
4310         expand_string_message = US"missing '}' closing lookup file-or-query arg";
4311         goto EXPAND_FAILED_CURLY;
4312         }
4313       while (isspace(*s)) s++;
4314
4315       /* If this isn't a single-key+file lookup, re-arrange the variables
4316       to be appropriate for the search_ functions. For query-style lookups,
4317       there is just a "key", and no file name. For the special query-style +
4318       file types, the query (i.e. "key") starts with a file name. */
4319
4320       if (!key)
4321         {
4322         while (isspace(*filename)) filename++;
4323         key = filename;
4324
4325         if (mac_islookup(stype, lookup_querystyle))
4326           filename = NULL;
4327         else
4328           {
4329           if (*filename != '/')
4330             {
4331             expand_string_message = string_sprintf(
4332               "absolute file name expected for \"%s\" lookup", name);
4333             goto EXPAND_FAILED;
4334             }
4335           while (*key != 0 && !isspace(*key)) key++;
4336           if (*key != 0) *key++ = 0;
4337           }
4338         }
4339
4340       /* If skipping, don't do the next bit - just lookup_value == NULL, as if
4341       the entry was not found. Note that there is no search_close() function.
4342       Files are left open in case of re-use. At suitable places in higher logic,
4343       search_tidyup() is called to tidy all open files. This can save opening
4344       the same file several times. However, files may also get closed when
4345       others are opened, if too many are open at once. The rule is that a
4346       handle should not be used after a second search_open().
4347
4348       Request that a partial search sets up $1 and maybe $2 by passing
4349       expand_setup containing zero. If its value changes, reset expand_nmax,
4350       since new variables will have been set. Note that at the end of this
4351       "lookup" section, the old numeric variables are restored. */
4352
4353       if (skipping)
4354         lookup_value = NULL;
4355       else
4356         {
4357         void *handle = search_open(filename, stype, 0, NULL, NULL);
4358         if (handle == NULL)
4359           {
4360           expand_string_message = search_error_message;
4361           goto EXPAND_FAILED;
4362           }
4363         lookup_value = search_find(handle, filename, key, partial, affix,
4364           affixlen, starflags, &expand_setup);
4365         if (search_find_defer)
4366           {
4367           expand_string_message =
4368             string_sprintf("lookup of \"%s\" gave DEFER: %s",
4369               string_printing2(key, FALSE), search_error_message);
4370           goto EXPAND_FAILED;
4371           }
4372         if (expand_setup > 0) expand_nmax = expand_setup;
4373         }
4374
4375       /* The handling of "yes" and "no" result strings is now in a separate
4376       function that is also used by ${if} and ${extract}. */
4377
4378       switch(process_yesno(
4379                skipping,                     /* were previously skipping */
4380                lookup_value != NULL,         /* success/failure indicator */
4381                save_lookup_value,            /* value to reset for string2 */
4382                &s,                           /* input pointer */
4383                &yield,                       /* output pointer */
4384                &size,                        /* output size */
4385                &ptr,                         /* output current point */
4386                US"lookup",                   /* condition type */
4387                &resetok))
4388         {
4389         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4390         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4391         }
4392
4393       /* Restore external setting of expansion variables for carrying on
4394       at this level, and continue. */
4395
4396       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4397         save_expand_nlength);
4398       continue;
4399       }
4400
4401     /* If Perl support is configured, handle calling embedded perl subroutines,
4402     unless locked out at this time. Syntax is ${perl{sub}} or ${perl{sub}{arg}}
4403     or ${perl{sub}{arg1}{arg2}} or up to a maximum of EXIM_PERL_MAX_ARGS
4404     arguments (defined below). */
4405
4406     #define EXIM_PERL_MAX_ARGS 8
4407
4408     case EITEM_PERL:
4409     #ifndef EXIM_PERL
4410     expand_string_message = US"\"${perl\" encountered, but this facility "      /*}*/
4411       "is not included in this binary";
4412     goto EXPAND_FAILED;
4413
4414     #else   /* EXIM_PERL */
4415       {
4416       uschar *sub_arg[EXIM_PERL_MAX_ARGS + 2];
4417       uschar *new_yield;
4418
4419       if ((expand_forbid & RDO_PERL) != 0)
4420         {
4421         expand_string_message = US"Perl calls are not permitted";
4422         goto EXPAND_FAILED;
4423         }
4424
4425       switch(read_subs(sub_arg, EXIM_PERL_MAX_ARGS + 1, 1, &s, skipping, TRUE,
4426            US"perl", &resetok))
4427         {
4428         case 1: goto EXPAND_FAILED_CURLY;
4429         case 2:
4430         case 3: goto EXPAND_FAILED;
4431         }
4432
4433       /* If skipping, we don't actually do anything */
4434
4435       if (skipping) continue;
4436
4437       /* Start the interpreter if necessary */
4438
4439       if (!opt_perl_started)
4440         {
4441         uschar *initerror;
4442         if (opt_perl_startup == NULL)
4443           {
4444           expand_string_message = US"A setting of perl_startup is needed when "
4445             "using the Perl interpreter";
4446           goto EXPAND_FAILED;
4447           }
4448         DEBUG(D_any) debug_printf("Starting Perl interpreter\n");
4449         initerror = init_perl(opt_perl_startup);
4450         if (initerror != NULL)
4451           {
4452           expand_string_message =
4453             string_sprintf("error in perl_startup code: %s\n", initerror);
4454           goto EXPAND_FAILED;
4455           }
4456         opt_perl_started = TRUE;
4457         }
4458
4459       /* Call the function */
4460
4461       sub_arg[EXIM_PERL_MAX_ARGS + 1] = NULL;
4462       new_yield = call_perl_cat(yield, &size, &ptr, &expand_string_message,
4463         sub_arg[0], sub_arg + 1);
4464
4465       /* NULL yield indicates failure; if the message pointer has been set to
4466       NULL, the yield was undef, indicating a forced failure. Otherwise the
4467       message will indicate some kind of Perl error. */
4468
4469       if (new_yield == NULL)
4470         {
4471         if (expand_string_message == NULL)
4472           {
4473           expand_string_message =
4474             string_sprintf("Perl subroutine \"%s\" returned undef to force "
4475               "failure", sub_arg[0]);
4476           expand_string_forcedfail = TRUE;
4477           }
4478         goto EXPAND_FAILED;
4479         }
4480
4481       /* Yield succeeded. Ensure forcedfail is unset, just in case it got
4482       set during a callback from Perl. */
4483
4484       expand_string_forcedfail = FALSE;
4485       yield = new_yield;
4486       continue;
4487       }
4488     #endif /* EXIM_PERL */
4489
4490     /* Transform email address to "prvs" scheme to use
4491        as BATV-signed return path */
4492
4493     case EITEM_PRVS:
4494       {
4495       uschar *sub_arg[3];
4496       uschar *p,*domain;
4497
4498       switch(read_subs(sub_arg, 3, 2, &s, skipping, TRUE, US"prvs", &resetok))
4499         {
4500         case 1: goto EXPAND_FAILED_CURLY;
4501         case 2:
4502         case 3: goto EXPAND_FAILED;
4503         }
4504
4505       /* If skipping, we don't actually do anything */
4506       if (skipping) continue;
4507
4508       /* sub_arg[0] is the address */
4509       domain = Ustrrchr(sub_arg[0],'@');
4510       if ( (domain == NULL) || (domain == sub_arg[0]) || (Ustrlen(domain) == 1) )
4511         {
4512         expand_string_message = US"prvs first argument must be a qualified email address";
4513         goto EXPAND_FAILED;
4514         }
4515
4516       /* Calculate the hash. The second argument must be a single-digit
4517       key number, or unset. */
4518
4519       if (sub_arg[2] != NULL &&
4520           (!isdigit(sub_arg[2][0]) || sub_arg[2][1] != 0))
4521         {
4522         expand_string_message = US"prvs second argument must be a single digit";
4523         goto EXPAND_FAILED;
4524         }
4525
4526       p = prvs_hmac_sha1(sub_arg[0],sub_arg[1],sub_arg[2],prvs_daystamp(7));
4527       if (p == NULL)
4528         {
4529         expand_string_message = US"prvs hmac-sha1 conversion failed";
4530         goto EXPAND_FAILED;
4531         }
4532
4533       /* Now separate the domain from the local part */
4534       *domain++ = '\0';
4535
4536       yield = string_catn(yield, &size, &ptr, US"prvs=", 5);
4537       yield = string_catn(yield, &size, &ptr, sub_arg[2] ? sub_arg[2] : US"0", 1);
4538       yield = string_catn(yield, &size, &ptr, prvs_daystamp(7), 3);
4539       yield = string_catn(yield, &size, &ptr, p, 6);
4540       yield = string_catn(yield, &size, &ptr, US"=", 1);
4541       yield = string_cat (yield, &size, &ptr, sub_arg[0]);
4542       yield = string_catn(yield, &size, &ptr, US"@", 1);
4543       yield = string_cat (yield, &size, &ptr, domain);
4544
4545       continue;
4546       }
4547
4548     /* Check a prvs-encoded address for validity */
4549
4550     case EITEM_PRVSCHECK:
4551       {
4552       uschar *sub_arg[3];
4553       int mysize = 0, myptr = 0;
4554       const pcre *re;
4555       uschar *p;
4556
4557       /* TF: Ugliness: We want to expand parameter 1 first, then set
4558          up expansion variables that are used in the expansion of
4559          parameter 2. So we clone the string for the first
4560          expansion, where we only expand parameter 1.
4561
4562          PH: Actually, that isn't necessary. The read_subs() function is
4563          designed to work this way for the ${if and ${lookup expansions. I've
4564          tidied the code.
4565       */
4566
4567       /* Reset expansion variables */
4568       prvscheck_result = NULL;
4569       prvscheck_address = NULL;
4570       prvscheck_keynum = NULL;
4571
4572       switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs", &resetok))
4573         {
4574         case 1: goto EXPAND_FAILED_CURLY;
4575         case 2:
4576         case 3: goto EXPAND_FAILED;
4577         }
4578
4579       re = regex_must_compile(US"^prvs\\=([0-9])([0-9]{3})([A-F0-9]{6})\\=(.+)\\@(.+)$",
4580                               TRUE,FALSE);
4581
4582       if (regex_match_and_setup(re,sub_arg[0],0,-1))
4583         {
4584         uschar *local_part = string_copyn(expand_nstring[4],expand_nlength[4]);
4585         uschar *key_num = string_copyn(expand_nstring[1],expand_nlength[1]);
4586         uschar *daystamp = string_copyn(expand_nstring[2],expand_nlength[2]);
4587         uschar *hash = string_copyn(expand_nstring[3],expand_nlength[3]);
4588         uschar *domain = string_copyn(expand_nstring[5],expand_nlength[5]);
4589
4590         DEBUG(D_expand) debug_printf_indent("prvscheck localpart: %s\n", local_part);
4591         DEBUG(D_expand) debug_printf_indent("prvscheck key number: %s\n", key_num);
4592         DEBUG(D_expand) debug_printf_indent("prvscheck daystamp: %s\n", daystamp);
4593         DEBUG(D_expand) debug_printf_indent("prvscheck hash: %s\n", hash);
4594         DEBUG(D_expand) debug_printf_indent("prvscheck domain: %s\n", domain);
4595
4596         /* Set up expansion variables */
4597         prvscheck_address = string_cat (NULL, &mysize, &myptr, local_part);
4598         prvscheck_address = string_catn(prvscheck_address, &mysize, &myptr, US"@", 1);
4599         prvscheck_address = string_cat (prvscheck_address, &mysize, &myptr, domain);
4600         prvscheck_address[myptr] = '\0';
4601         prvscheck_keynum = string_copy(key_num);
4602
4603         /* Now expand the second argument */
4604         switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs", &resetok))
4605           {
4606           case 1: goto EXPAND_FAILED_CURLY;
4607           case 2:
4608           case 3: goto EXPAND_FAILED;
4609           }
4610
4611         /* Now we have the key and can check the address. */
4612
4613         p = prvs_hmac_sha1(prvscheck_address, sub_arg[0], prvscheck_keynum,
4614           daystamp);
4615
4616         if (p == NULL)
4617           {
4618           expand_string_message = US"hmac-sha1 conversion failed";
4619           goto EXPAND_FAILED;
4620           }
4621
4622         DEBUG(D_expand) debug_printf_indent("prvscheck: received hash is %s\n", hash);
4623         DEBUG(D_expand) debug_printf_indent("prvscheck:      own hash is %s\n", p);
4624
4625         if (Ustrcmp(p,hash) == 0)
4626           {
4627           /* Success, valid BATV address. Now check the expiry date. */
4628           uschar *now = prvs_daystamp(0);
4629           unsigned int inow = 0,iexpire = 1;
4630
4631           (void)sscanf(CS now,"%u",&inow);
4632           (void)sscanf(CS daystamp,"%u",&iexpire);
4633
4634           /* When "iexpire" is < 7, a "flip" has occured.
4635              Adjust "inow" accordingly. */
4636           if ( (iexpire < 7) && (inow >= 993) ) inow = 0;
4637
4638           if (iexpire >= inow)
4639             {
4640             prvscheck_result = US"1";
4641             DEBUG(D_expand) debug_printf_indent("prvscheck: success, $pvrs_result set to 1\n");
4642             }
4643             else
4644             {
4645             prvscheck_result = NULL;
4646             DEBUG(D_expand) debug_printf_indent("prvscheck: signature expired, $pvrs_result unset\n");
4647             }
4648           }
4649         else
4650           {
4651           prvscheck_result = NULL;
4652           DEBUG(D_expand) debug_printf_indent("prvscheck: hash failure, $pvrs_result unset\n");
4653           }
4654
4655         /* Now expand the final argument. We leave this till now so that
4656         it can include $prvscheck_result. */
4657
4658         switch(read_subs(sub_arg, 1, 0, &s, skipping, TRUE, US"prvs", &resetok))
4659           {
4660           case 1: goto EXPAND_FAILED_CURLY;
4661           case 2:
4662           case 3: goto EXPAND_FAILED;
4663           }
4664
4665         yield = string_cat(yield, &size, &ptr,
4666           !sub_arg[0] || !*sub_arg[0] ? prvscheck_address : sub_arg[0]);
4667
4668         /* Reset the "internal" variables afterwards, because they are in
4669         dynamic store that will be reclaimed if the expansion succeeded. */
4670
4671         prvscheck_address = NULL;
4672         prvscheck_keynum = NULL;
4673         }
4674       else
4675         /* Does not look like a prvs encoded address, return the empty string.
4676            We need to make sure all subs are expanded first, so as to skip over
4677            the entire item. */
4678
4679         switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"prvs", &resetok))
4680           {
4681           case 1: goto EXPAND_FAILED_CURLY;
4682           case 2:
4683           case 3: goto EXPAND_FAILED;
4684           }
4685
4686       continue;
4687       }
4688
4689     /* Handle "readfile" to insert an entire file */
4690
4691     case EITEM_READFILE:
4692       {
4693       FILE *f;
4694       uschar *sub_arg[2];
4695
4696       if ((expand_forbid & RDO_READFILE) != 0)
4697         {
4698         expand_string_message = US"file insertions are not permitted";
4699         goto EXPAND_FAILED;
4700         }
4701
4702       switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"readfile", &resetok))
4703         {
4704         case 1: goto EXPAND_FAILED_CURLY;
4705         case 2:
4706         case 3: goto EXPAND_FAILED;
4707         }
4708
4709       /* If skipping, we don't actually do anything */
4710
4711       if (skipping) continue;
4712
4713       /* Open the file and read it */
4714
4715       f = Ufopen(sub_arg[0], "rb");
4716       if (f == NULL)
4717         {
4718         expand_string_message = string_open_failed(errno, "%s", sub_arg[0]);
4719         goto EXPAND_FAILED;
4720         }
4721
4722       yield = cat_file(f, yield, &size, &ptr, sub_arg[1]);
4723       (void)fclose(f);
4724       continue;
4725       }
4726
4727     /* Handle "readsocket" to insert data from a Unix domain socket */
4728
4729     case EITEM_READSOCK:
4730       {
4731       int fd;
4732       int timeout = 5;
4733       int save_ptr = ptr;
4734       FILE *f;
4735       struct sockaddr_un sockun;         /* don't call this "sun" ! */
4736       uschar *arg;
4737       uschar *sub_arg[4];
4738       BOOL do_shutdown = TRUE;
4739
4740       if (expand_forbid & RDO_READSOCK)
4741         {
4742         expand_string_message = US"socket insertions are not permitted";
4743         goto EXPAND_FAILED;
4744         }
4745
4746       /* Read up to 4 arguments, but don't do the end of item check afterwards,
4747       because there may be a string for expansion on failure. */
4748
4749       switch(read_subs(sub_arg, 4, 2, &s, skipping, FALSE, US"readsocket", &resetok))
4750         {
4751         case 1: goto EXPAND_FAILED_CURLY;
4752         case 2:                             /* Won't occur: no end check */
4753         case 3: goto EXPAND_FAILED;
4754         }
4755
4756       /* Sort out timeout, if given.  The second arg is a list with the first element
4757       being a time value.  Any more are options of form "name=value".  Currently the
4758       only option recognised is "shutdown". */
4759
4760       if (sub_arg[2])
4761         {
4762         const uschar * list = sub_arg[2];
4763         uschar * item;
4764         int sep = 0;
4765
4766         item = string_nextinlist(&list, &sep, NULL, 0);
4767         if ((timeout = readconf_readtime(item, 0, FALSE)) < 0)
4768           {
4769           expand_string_message = string_sprintf("bad time value %s", item);
4770           goto EXPAND_FAILED;
4771           }
4772
4773         while ((item = string_nextinlist(&list, &sep, NULL, 0)))
4774           if (Ustrncmp(item, US"shutdown=", 9) == 0)
4775             if (Ustrcmp(item + 9, US"no") == 0)
4776               do_shutdown = FALSE;
4777         }
4778       else sub_arg[3] = NULL;                     /* No eol if no timeout */
4779
4780       /* If skipping, we don't actually do anything. Otherwise, arrange to
4781       connect to either an IP or a Unix socket. */
4782
4783       if (!skipping)
4784         {
4785         /* Handle an IP (internet) domain */
4786
4787         if (Ustrncmp(sub_arg[0], "inet:", 5) == 0)
4788           {
4789           int port;
4790           uschar *server_name = sub_arg[0] + 5;
4791           uschar *port_name = Ustrrchr(server_name, ':');
4792
4793           /* Sort out the port */
4794
4795           if (port_name == NULL)
4796             {
4797             expand_string_message =
4798               string_sprintf("missing port for readsocket %s", sub_arg[0]);
4799             goto EXPAND_FAILED;
4800             }
4801           *port_name++ = 0;           /* Terminate server name */
4802
4803           if (isdigit(*port_name))
4804             {
4805             uschar *end;
4806             port = Ustrtol(port_name, &end, 0);
4807             if (end != port_name + Ustrlen(port_name))
4808               {
4809               expand_string_message =
4810                 string_sprintf("invalid port number %s", port_name);
4811               goto EXPAND_FAILED;
4812               }
4813             }
4814           else
4815             {
4816             struct servent *service_info = getservbyname(CS port_name, "tcp");
4817             if (service_info == NULL)
4818               {
4819               expand_string_message = string_sprintf("unknown port \"%s\"",
4820                 port_name);
4821               goto EXPAND_FAILED;
4822               }
4823             port = ntohs(service_info->s_port);
4824             }
4825
4826           fd = ip_connectedsocket(SOCK_STREAM, server_name, port, port,
4827                   timeout, NULL, &expand_string_message);
4828           callout_address = NULL;
4829           if (fd < 0)
4830               goto SOCK_FAIL;
4831           }
4832
4833         /* Handle a Unix domain socket */
4834
4835         else
4836           {
4837           int rc;
4838           if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
4839             {
4840             expand_string_message = string_sprintf("failed to create socket: %s",
4841               strerror(errno));
4842             goto SOCK_FAIL;
4843             }
4844
4845           sockun.sun_family = AF_UNIX;
4846           sprintf(sockun.sun_path, "%.*s", (int)(sizeof(sockun.sun_path)-1),
4847             sub_arg[0]);
4848
4849           sigalrm_seen = FALSE;
4850           alarm(timeout);
4851           rc = connect(fd, (struct sockaddr *)(&sockun), sizeof(sockun));
4852           alarm(0);
4853           if (sigalrm_seen)
4854             {
4855             expand_string_message = US "socket connect timed out";
4856             goto SOCK_FAIL;
4857             }
4858           if (rc < 0)
4859             {
4860             expand_string_message = string_sprintf("failed to connect to socket "
4861               "%s: %s", sub_arg[0], strerror(errno));
4862             goto SOCK_FAIL;
4863             }
4864           }
4865
4866         DEBUG(D_expand) debug_printf_indent("connected to socket %s\n", sub_arg[0]);
4867
4868         /* Allow sequencing of test actions */
4869         if (running_in_test_harness) millisleep(100);
4870
4871         /* Write the request string, if not empty */
4872
4873         if (sub_arg[1][0] != 0)
4874           {
4875           int len = Ustrlen(sub_arg[1]);
4876           DEBUG(D_expand) debug_printf_indent("writing \"%s\" to socket\n",
4877             sub_arg[1]);
4878           if (write(fd, sub_arg[1], len) != len)
4879             {
4880             expand_string_message = string_sprintf("request write to socket "
4881               "failed: %s", strerror(errno));
4882             goto SOCK_FAIL;
4883             }
4884           }
4885
4886         /* Shut down the sending side of the socket. This helps some servers to
4887         recognise that it is their turn to do some work. Just in case some
4888         system doesn't have this function, make it conditional. */
4889
4890 #ifdef SHUT_WR
4891         if (do_shutdown) shutdown(fd, SHUT_WR);
4892 #endif
4893
4894         if (running_in_test_harness) millisleep(100);
4895
4896         /* Now we need to read from the socket, under a timeout. The function
4897         that reads a file can be used. */
4898
4899         f = fdopen(fd, "rb");
4900         sigalrm_seen = FALSE;
4901         alarm(timeout);
4902         yield = cat_file(f, yield, &size, &ptr, sub_arg[3]);
4903         alarm(0);
4904         (void)fclose(f);
4905
4906         /* After a timeout, we restore the pointer in the result, that is,
4907         make sure we add nothing from the socket. */
4908
4909         if (sigalrm_seen)
4910           {
4911           ptr = save_ptr;
4912           expand_string_message = US "socket read timed out";
4913           goto SOCK_FAIL;
4914           }
4915         }
4916
4917       /* The whole thing has worked (or we were skipping). If there is a
4918       failure string following, we need to skip it. */
4919
4920       if (*s == '{')
4921         {
4922         if (expand_string_internal(s+1, TRUE, &s, TRUE, TRUE, &resetok) == NULL)
4923           goto EXPAND_FAILED;
4924         if (*s++ != '}')
4925           {
4926           expand_string_message = US"missing '}' closing failstring for readsocket";
4927           goto EXPAND_FAILED_CURLY;
4928           }
4929         while (isspace(*s)) s++;
4930         }
4931
4932     READSOCK_DONE:
4933       if (*s++ != '}')
4934         {
4935         expand_string_message = US"missing '}' closing readsocket";
4936         goto EXPAND_FAILED_CURLY;
4937         }
4938       continue;
4939
4940       /* Come here on failure to create socket, connect socket, write to the
4941       socket, or timeout on reading. If another substring follows, expand and
4942       use it. Otherwise, those conditions give expand errors. */
4943
4944     SOCK_FAIL:
4945       if (*s != '{') goto EXPAND_FAILED;
4946       DEBUG(D_any) debug_printf("%s\n", expand_string_message);
4947       if (!(arg = expand_string_internal(s+1, TRUE, &s, FALSE, TRUE, &resetok)))
4948         goto EXPAND_FAILED;
4949       yield = string_cat(yield, &size, &ptr, arg);
4950       if (*s++ != '}')
4951         {
4952         expand_string_message = US"missing '}' closing failstring for readsocket";
4953         goto EXPAND_FAILED_CURLY;
4954         }
4955       while (isspace(*s)) s++;
4956       goto READSOCK_DONE;
4957       }
4958
4959     /* Handle "run" to execute a program. */
4960
4961     case EITEM_RUN:
4962       {
4963       FILE *f;
4964       uschar *arg;
4965       const uschar **argv;
4966       pid_t pid;
4967       int fd_in, fd_out;
4968       int lsize = 0, lptr = 0;
4969
4970       if ((expand_forbid & RDO_RUN) != 0)
4971         {
4972         expand_string_message = US"running a command is not permitted";
4973         goto EXPAND_FAILED;
4974         }
4975
4976       while (isspace(*s)) s++;
4977       if (*s != '{')
4978         {
4979         expand_string_message = US"missing '{' for command arg of run";
4980         goto EXPAND_FAILED_CURLY;
4981         }
4982       arg = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
4983       if (arg == NULL) goto EXPAND_FAILED;
4984       while (isspace(*s)) s++;
4985       if (*s++ != '}')
4986         {
4987         expand_string_message = US"missing '}' closing command arg of run";
4988         goto EXPAND_FAILED_CURLY;
4989         }
4990
4991       if (skipping)   /* Just pretend it worked when we're skipping */
4992         {
4993         runrc = 0;
4994         lookup_value = NULL;
4995         }
4996       else
4997         {
4998         if (!transport_set_up_command(&argv,    /* anchor for arg list */
4999             arg,                                /* raw command */
5000             FALSE,                              /* don't expand the arguments */
5001             0,                                  /* not relevant when... */
5002             NULL,                               /* no transporting address */
5003             US"${run} expansion",               /* for error messages */
5004             &expand_string_message))            /* where to put error message */
5005           goto EXPAND_FAILED;
5006
5007         /* Create the child process, making it a group leader. */
5008
5009         if ((pid = child_open(USS argv, NULL, 0077, &fd_in, &fd_out, TRUE)) < 0)
5010           {
5011           expand_string_message =
5012             string_sprintf("couldn't create child process: %s", strerror(errno));
5013           goto EXPAND_FAILED;
5014           }
5015
5016         /* Nothing is written to the standard input. */
5017
5018         (void)close(fd_in);
5019
5020         /* Read the pipe to get the command's output into $value (which is kept
5021         in lookup_value). Read during execution, so that if the output exceeds
5022         the OS pipe buffer limit, we don't block forever. Remember to not release
5023         memory just allocated for $value. */
5024
5025         resetok = FALSE;
5026         f = fdopen(fd_out, "rb");
5027         sigalrm_seen = FALSE;
5028         alarm(60);
5029         lookup_value = cat_file(f, NULL, &lsize, &lptr, NULL);
5030         alarm(0);
5031         (void)fclose(f);
5032
5033         /* Wait for the process to finish, applying the timeout, and inspect its
5034         return code for serious disasters. Simple non-zero returns are passed on.
5035         */
5036
5037         if (sigalrm_seen || (runrc = child_close(pid, 30)) < 0)
5038           {
5039           if (sigalrm_seen || runrc == -256)
5040             {
5041             expand_string_message = string_sprintf("command timed out");
5042             killpg(pid, SIGKILL);       /* Kill the whole process group */
5043             }
5044
5045           else if (runrc == -257)
5046             expand_string_message = string_sprintf("wait() failed: %s",
5047               strerror(errno));
5048
5049           else
5050             expand_string_message = string_sprintf("command killed by signal %d",
5051               -runrc);
5052
5053           goto EXPAND_FAILED;
5054           }
5055         }
5056
5057       /* Process the yes/no strings; $value may be useful in both cases */
5058
5059       switch(process_yesno(
5060                skipping,                     /* were previously skipping */
5061                runrc == 0,                   /* success/failure indicator */
5062                lookup_value,                 /* value to reset for string2 */
5063                &s,                           /* input pointer */
5064                &yield,                       /* output pointer */
5065                &size,                        /* output size */
5066                &ptr,                         /* output current point */
5067                US"run",                      /* condition type */
5068                &resetok))
5069         {
5070         case 1: goto EXPAND_FAILED;          /* when all is well, the */
5071         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
5072         }
5073
5074       continue;
5075       }
5076
5077     /* Handle character translation for "tr" */
5078
5079     case EITEM_TR:
5080       {
5081       int oldptr = ptr;
5082       int o2m;
5083       uschar *sub[3];
5084
5085       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"tr", &resetok))
5086         {
5087         case 1: goto EXPAND_FAILED_CURLY;
5088         case 2:
5089         case 3: goto EXPAND_FAILED;
5090         }
5091
5092       yield = string_cat(yield, &size, &ptr, sub[0]);
5093       o2m = Ustrlen(sub[2]) - 1;
5094
5095       if (o2m >= 0) for (; oldptr < ptr; oldptr++)
5096         {
5097         uschar *m = Ustrrchr(sub[1], yield[oldptr]);
5098         if (m != NULL)
5099           {
5100           int o = m - sub[1];
5101           yield[oldptr] = sub[2][(o < o2m)? o : o2m];
5102           }
5103         }
5104
5105       continue;
5106       }
5107
5108     /* Handle "hash", "length", "nhash", and "substr" when they are given with
5109     expanded arguments. */
5110
5111     case EITEM_HASH:
5112     case EITEM_LENGTH:
5113     case EITEM_NHASH:
5114     case EITEM_SUBSTR:
5115       {
5116       int i;
5117       int len;
5118       uschar *ret;
5119       int val[2] = { 0, -1 };
5120       uschar *sub[3];
5121
5122       /* "length" takes only 2 arguments whereas the others take 2 or 3.
5123       Ensure that sub[2] is set in the ${length } case. */
5124
5125       sub[2] = NULL;
5126       switch(read_subs(sub, (item_type == EITEM_LENGTH)? 2:3, 2, &s, skipping,
5127              TRUE, name, &resetok))
5128         {
5129         case 1: goto EXPAND_FAILED_CURLY;
5130         case 2:
5131         case 3: goto EXPAND_FAILED;
5132         }
5133
5134       /* Juggle the arguments if there are only two of them: always move the
5135       string to the last position and make ${length{n}{str}} equivalent to
5136       ${substr{0}{n}{str}}. See the defaults for val[] above. */
5137
5138       if (sub[2] == NULL)
5139         {
5140         sub[2] = sub[1];
5141         sub[1] = NULL;
5142         if (item_type == EITEM_LENGTH)
5143           {
5144           sub[1] = sub[0];
5145           sub[0] = NULL;
5146           }
5147         }
5148
5149       for (i = 0; i < 2; i++)
5150         {
5151         if (sub[i] == NULL) continue;
5152         val[i] = (int)Ustrtol(sub[i], &ret, 10);
5153         if (*ret != 0 || (i != 0 && val[i] < 0))
5154           {
5155           expand_string_message = string_sprintf("\"%s\" is not a%s number "
5156             "(in \"%s\" expansion)", sub[i], (i != 0)? " positive" : "", name);
5157           goto EXPAND_FAILED;
5158           }
5159         }
5160
5161       ret =
5162         (item_type == EITEM_HASH)?
5163           compute_hash(sub[2], val[0], val[1], &len) :
5164         (item_type == EITEM_NHASH)?
5165           compute_nhash(sub[2], val[0], val[1], &len) :
5166           extract_substr(sub[2], val[0], val[1], &len);
5167
5168       if (ret == NULL) goto EXPAND_FAILED;
5169       yield = string_catn(yield, &size, &ptr, ret, len);
5170       continue;
5171       }
5172
5173     /* Handle HMAC computation: ${hmac{<algorithm>}{<secret>}{<text>}}
5174     This code originally contributed by Steve Haslam. It currently supports
5175     the use of MD5 and SHA-1 hashes.
5176
5177     We need some workspace that is large enough to handle all the supported
5178     hash types. Use macros to set the sizes rather than be too elaborate. */
5179
5180     #define MAX_HASHLEN      20
5181     #define MAX_HASHBLOCKLEN 64
5182
5183     case EITEM_HMAC:
5184       {
5185       uschar *sub[3];
5186       md5 md5_base;
5187       hctx sha1_ctx;
5188       void *use_base;
5189       int type, i;
5190       int hashlen;      /* Number of octets for the hash algorithm's output */
5191       int hashblocklen; /* Number of octets the hash algorithm processes */
5192       uschar *keyptr, *p;
5193       unsigned int keylen;
5194
5195       uschar keyhash[MAX_HASHLEN];
5196       uschar innerhash[MAX_HASHLEN];
5197       uschar finalhash[MAX_HASHLEN];
5198       uschar finalhash_hex[2*MAX_HASHLEN];
5199       uschar innerkey[MAX_HASHBLOCKLEN];
5200       uschar outerkey[MAX_HASHBLOCKLEN];
5201
5202       switch (read_subs(sub, 3, 3, &s, skipping, TRUE, name, &resetok))
5203         {
5204         case 1: goto EXPAND_FAILED_CURLY;
5205         case 2:
5206         case 3: goto EXPAND_FAILED;
5207         }
5208
5209       if (!skipping)
5210         {
5211         if (Ustrcmp(sub[0], "md5") == 0)
5212           {
5213           type = HMAC_MD5;
5214           use_base = &md5_base;
5215           hashlen = 16;
5216           hashblocklen = 64;
5217           }
5218         else if (Ustrcmp(sub[0], "sha1") == 0)
5219           {
5220           type = HMAC_SHA1;
5221           use_base = &sha1_ctx;
5222           hashlen = 20;
5223           hashblocklen = 64;
5224           }
5225         else
5226           {
5227           expand_string_message =
5228             string_sprintf("hmac algorithm \"%s\" is not recognised", sub[0]);
5229           goto EXPAND_FAILED;
5230           }
5231
5232         keyptr = sub[1];
5233         keylen = Ustrlen(keyptr);
5234
5235         /* If the key is longer than the hash block length, then hash the key
5236         first */
5237
5238         if (keylen > hashblocklen)
5239           {
5240           chash_start(type, use_base);
5241           chash_end(type, use_base, keyptr, keylen, keyhash);
5242           keyptr = keyhash;
5243           keylen = hashlen;
5244           }
5245
5246         /* Now make the inner and outer key values */
5247
5248         memset(innerkey, 0x36, hashblocklen);
5249         memset(outerkey, 0x5c, hashblocklen);
5250
5251         for (i = 0; i < keylen; i++)
5252           {
5253           innerkey[i] ^= keyptr[i];
5254           outerkey[i] ^= keyptr[i];
5255           }
5256
5257         /* Now do the hashes */
5258
5259         chash_start(type, use_base);
5260         chash_mid(type, use_base, innerkey);
5261         chash_end(type, use_base, sub[2], Ustrlen(sub[2]), innerhash);
5262
5263         chash_start(type, use_base);
5264         chash_mid(type, use_base, outerkey);
5265         chash_end(type, use_base, innerhash, hashlen, finalhash);
5266
5267         /* Encode the final hash as a hex string */
5268
5269         p = finalhash_hex;
5270         for (i = 0; i < hashlen; i++)
5271           {
5272           *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
5273           *p++ = hex_digits[finalhash[i] & 0x0f];
5274           }
5275
5276         DEBUG(D_any) debug_printf("HMAC[%s](%.*s,%s)=%.*s\n",
5277           sub[0], (int)keylen, keyptr, sub[2], hashlen*2, finalhash_hex);
5278
5279         yield = string_catn(yield, &size, &ptr, finalhash_hex, hashlen*2);
5280         }
5281       continue;
5282       }
5283
5284     /* Handle global substitution for "sg" - like Perl's s/xxx/yyy/g operator.
5285     We have to save the numerical variables and restore them afterwards. */
5286
5287     case EITEM_SG:
5288       {
5289       const pcre *re;
5290       int moffset, moffsetextra, slen;
5291       int roffset;
5292       int emptyopt;
5293       const uschar *rerror;
5294       uschar *subject;
5295       uschar *sub[3];
5296       int save_expand_nmax =
5297         save_expand_strings(save_expand_nstring, save_expand_nlength);
5298
5299       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"sg", &resetok))
5300         {
5301         case 1: goto EXPAND_FAILED_CURLY;
5302         case 2:
5303         case 3: goto EXPAND_FAILED;
5304         }
5305
5306       /* Compile the regular expression */
5307
5308       re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
5309         NULL);
5310
5311       if (re == NULL)
5312         {
5313         expand_string_message = string_sprintf("regular expression error in "
5314           "\"%s\": %s at offset %d", sub[1], rerror, roffset);
5315         goto EXPAND_FAILED;
5316         }
5317
5318       /* Now run a loop to do the substitutions as often as necessary. It ends
5319       when there are no more matches. Take care over matches of the null string;
5320       do the same thing as Perl does. */
5321
5322       subject = sub[0];
5323       slen = Ustrlen(sub[0]);
5324       moffset = moffsetextra = 0;
5325       emptyopt = 0;
5326
5327       for (;;)
5328         {
5329         int ovector[3*(EXPAND_MAXN+1)];
5330         int n = pcre_exec(re, NULL, CS subject, slen, moffset + moffsetextra,
5331           PCRE_EOPT | emptyopt, ovector, nelem(ovector));
5332         int nn;
5333         uschar *insert;
5334
5335         /* No match - if we previously set PCRE_NOTEMPTY after a null match, this
5336         is not necessarily the end. We want to repeat the match from one
5337         character further along, but leaving the basic offset the same (for
5338         copying below). We can't be at the end of the string - that was checked
5339         before setting PCRE_NOTEMPTY. If PCRE_NOTEMPTY is not set, we are
5340         finished; copy the remaining string and end the loop. */
5341
5342         if (n < 0)
5343           {
5344           if (emptyopt != 0)
5345             {
5346             moffsetextra = 1;
5347             emptyopt = 0;
5348             continue;
5349             }
5350           yield = string_catn(yield, &size, &ptr, subject+moffset, slen-moffset);
5351           break;
5352           }
5353
5354         /* Match - set up for expanding the replacement. */
5355
5356         if (n == 0) n = EXPAND_MAXN + 1;
5357         expand_nmax = 0;
5358         for (nn = 0; nn < n*2; nn += 2)
5359           {
5360           expand_nstring[expand_nmax] = subject + ovector[nn];
5361           expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
5362           }
5363         expand_nmax--;
5364
5365         /* Copy the characters before the match, plus the expanded insertion. */
5366
5367         yield = string_catn(yield, &size, &ptr, subject + moffset,
5368           ovector[0] - moffset);
5369         insert = expand_string(sub[2]);
5370         if (insert == NULL) goto EXPAND_FAILED;
5371         yield = string_cat(yield, &size, &ptr, insert);
5372
5373         moffset = ovector[1];
5374         moffsetextra = 0;
5375         emptyopt = 0;
5376
5377         /* If we have matched an empty string, first check to see if we are at
5378         the end of the subject. If so, the loop is over. Otherwise, mimic
5379         what Perl's /g options does. This turns out to be rather cunning. First
5380         we set PCRE_NOTEMPTY and PCRE_ANCHORED and try the match a non-empty
5381         string at the same point. If this fails (picked up above) we advance to
5382         the next character. */
5383
5384         if (ovector[0] == ovector[1])
5385           {
5386           if (ovector[0] == slen) break;
5387           emptyopt = PCRE_NOTEMPTY | PCRE_ANCHORED;
5388           }
5389         }
5390
5391       /* All done - restore numerical variables. */
5392
5393       restore_expand_strings(save_expand_nmax, save_expand_nstring,
5394         save_expand_nlength);
5395       continue;
5396       }
5397
5398     /* Handle keyed and numbered substring extraction. If the first argument
5399     consists entirely of digits, then a numerical extraction is assumed. */
5400
5401     case EITEM_EXTRACT:
5402       {
5403       int i;
5404       int j;
5405       int field_number = 1;
5406       BOOL field_number_set = FALSE;
5407       uschar *save_lookup_value = lookup_value;
5408       uschar *sub[3];
5409       int save_expand_nmax =
5410         save_expand_strings(save_expand_nstring, save_expand_nlength);
5411
5412       /* While skipping we cannot rely on the data for expansions being
5413       available (eg. $item) hence cannot decide on numeric vs. keyed.
5414       Read a maximum of 5 arguments (including the yes/no) */
5415
5416       if (skipping)
5417         {
5418         while (isspace(*s)) s++;
5419         for (j = 5; j > 0 && *s == '{'; j--)
5420           {
5421           if (!expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok))
5422             goto EXPAND_FAILED;                                 /*{*/
5423           if (*s++ != '}')
5424             {
5425             expand_string_message = US"missing '{' for arg of extract";
5426             goto EXPAND_FAILED_CURLY;
5427             }
5428           while (isspace(*s)) s++;
5429           }
5430         if (  Ustrncmp(s, "fail", 4) == 0
5431            && (s[4] == '}' || s[4] == ' ' || s[4] == '\t' || !s[4])
5432            )
5433           {
5434           s += 4;
5435           while (isspace(*s)) s++;
5436           }
5437         if (*s != '}')
5438           {
5439           expand_string_message = US"missing '}' closing extract";
5440           goto EXPAND_FAILED_CURLY;
5441           }
5442         }
5443
5444       else for (i = 0, j = 2; i < j; i++) /* Read the proper number of arguments */
5445         {
5446         while (isspace(*s)) s++;
5447         if (*s == '{')                                          /*}*/
5448           {
5449           sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
5450           if (sub[i] == NULL) goto EXPAND_FAILED;               /*{*/
5451           if (*s++ != '}')
5452             {
5453             expand_string_message = string_sprintf(
5454               "missing '}' closing arg %d of extract", i+1);
5455             goto EXPAND_FAILED_CURLY;
5456             }
5457
5458           /* After removal of leading and trailing white space, the first
5459           argument must not be empty; if it consists entirely of digits
5460           (optionally preceded by a minus sign), this is a numerical
5461           extraction, and we expect 3 arguments. */
5462
5463           if (i == 0)
5464             {
5465             int len;
5466             int x = 0;
5467             uschar *p = sub[0];
5468
5469             while (isspace(*p)) p++;
5470             sub[0] = p;
5471
5472             len = Ustrlen(p);
5473             while (len > 0 && isspace(p[len-1])) len--;
5474             p[len] = 0;
5475
5476             if (*p == 0)
5477               {
5478               expand_string_message = US"first argument of \"extract\" must "
5479                 "not be empty";
5480               goto EXPAND_FAILED;
5481               }
5482
5483             if (*p == '-')
5484               {
5485               field_number = -1;
5486               p++;
5487               }
5488             while (*p != 0 && isdigit(*p)) x = x * 10 + *p++ - '0';
5489             if (*p == 0)
5490               {
5491               field_number *= x;
5492               j = 3;               /* Need 3 args */
5493               field_number_set = TRUE;
5494               }
5495             }
5496           }
5497         else
5498           {
5499           expand_string_message = string_sprintf(
5500             "missing '{' for arg %d of extract", i+1);
5501           goto EXPAND_FAILED_CURLY;
5502           }
5503         }
5504
5505       /* Extract either the numbered or the keyed substring into $value. If
5506       skipping, just pretend the extraction failed. */
5507
5508       lookup_value = skipping? NULL : field_number_set?
5509         expand_gettokened(field_number, sub[1], sub[2]) :
5510         expand_getkeyed(sub[0], sub[1]);
5511
5512       /* If no string follows, $value gets substituted; otherwise there can
5513       be yes/no strings, as for lookup or if. */
5514
5515       switch(process_yesno(
5516                skipping,                     /* were previously skipping */
5517                lookup_value != NULL,         /* success/failure indicator */
5518                save_lookup_value,            /* value to reset for string2 */
5519                &s,                           /* input pointer */
5520                &yield,                       /* output pointer */
5521                &size,                        /* output size */
5522                &ptr,                         /* output current point */
5523                US"extract",                  /* condition type */
5524                &resetok))
5525         {
5526         case 1: goto EXPAND_FAILED;          /* when all is well, the */
5527         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
5528         }
5529
5530       /* All done - restore numerical variables. */
5531
5532       restore_expand_strings(save_expand_nmax, save_expand_nstring,
5533         save_expand_nlength);
5534
5535       continue;
5536       }
5537
5538     /* return the Nth item from a list */
5539
5540     case EITEM_LISTEXTRACT:
5541       {
5542       int i;
5543       int field_number = 1;
5544       uschar *save_lookup_value = lookup_value;
5545       uschar *sub[2];
5546       int save_expand_nmax =
5547         save_expand_strings(save_expand_nstring, save_expand_nlength);
5548
5549       /* Read the field & list arguments */
5550
5551       for (i = 0; i < 2; i++)
5552         {
5553         while (isspace(*s)) s++;
5554         if (*s != '{')                                  /*}*/
5555           {
5556           expand_string_message = string_sprintf(
5557             "missing '{' for arg %d of listextract", i+1);
5558           goto EXPAND_FAILED_CURLY;
5559           }
5560
5561         sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
5562         if (!sub[i])     goto EXPAND_FAILED;            /*{*/
5563         if (*s++ != '}')
5564           {
5565           expand_string_message = string_sprintf(
5566             "missing '}' closing arg %d of listextract", i+1);
5567           goto EXPAND_FAILED_CURLY;
5568           }
5569
5570         /* After removal of leading and trailing white space, the first
5571         argument must be numeric and nonempty. */
5572
5573         if (i == 0)
5574           {
5575           int len;
5576           int x = 0;
5577           uschar *p = sub[0];
5578
5579           while (isspace(*p)) p++;
5580           sub[0] = p;
5581
5582           len = Ustrlen(p);
5583           while (len > 0 && isspace(p[len-1])) len--;
5584           p[len] = 0;
5585
5586           if (!*p && !skipping)
5587             {
5588             expand_string_message = US"first argument of \"listextract\" must "
5589               "not be empty";
5590             goto EXPAND_FAILED;
5591             }
5592
5593           if (*p == '-')
5594             {
5595             field_number = -1;
5596             p++;
5597             }
5598           while (*p && isdigit(*p)) x = x * 10 + *p++ - '0';
5599           if (*p)
5600             {
5601             expand_string_message = US"first argument of \"listextract\" must "
5602               "be numeric";
5603             goto EXPAND_FAILED;
5604             }
5605           field_number *= x;
5606           }
5607         }
5608
5609       /* Extract the numbered element into $value. If
5610       skipping, just pretend the extraction failed. */
5611
5612       lookup_value = skipping? NULL : expand_getlistele(field_number, sub[1]);
5613
5614       /* If no string follows, $value gets substituted; otherwise there can
5615       be yes/no strings, as for lookup or if. */
5616
5617       switch(process_yesno(
5618                skipping,                     /* were previously skipping */
5619                lookup_value != NULL,         /* success/failure indicator */
5620                save_lookup_value,            /* value to reset for string2 */
5621                &s,                           /* input pointer */
5622                &yield,                       /* output pointer */
5623                &size,                        /* output size */
5624                &ptr,                         /* output current point */
5625                US"listextract",              /* condition type */
5626                &resetok))
5627         {
5628         case 1: goto EXPAND_FAILED;          /* when all is well, the */
5629         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
5630         }
5631
5632       /* All done - restore numerical variables. */
5633
5634       restore_expand_strings(save_expand_nmax, save_expand_nstring,
5635         save_expand_nlength);
5636
5637       continue;
5638       }
5639
5640 #ifdef SUPPORT_TLS
5641     case EITEM_CERTEXTRACT:
5642       {
5643       uschar *save_lookup_value = lookup_value;
5644       uschar *sub[2];
5645       int save_expand_nmax =
5646         save_expand_strings(save_expand_nstring, save_expand_nlength);
5647
5648       /* Read the field argument */
5649       while (isspace(*s)) s++;
5650       if (*s != '{')                                    /*}*/
5651         {
5652         expand_string_message = US"missing '{' for field arg of certextract";
5653         goto EXPAND_FAILED_CURLY;
5654         }
5655       sub[0] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
5656       if (!sub[0])     goto EXPAND_FAILED;              /*{*/
5657       if (*s++ != '}')
5658         {
5659         expand_string_message = US"missing '}' closing field arg of certextract";
5660         goto EXPAND_FAILED_CURLY;
5661         }
5662       /* strip spaces fore & aft */
5663       {
5664       int len;
5665       uschar *p = sub[0];
5666
5667       while (isspace(*p)) p++;
5668       sub[0] = p;
5669
5670       len = Ustrlen(p);
5671       while (len > 0 && isspace(p[len-1])) len--;
5672       p[len] = 0;
5673       }
5674
5675       /* inspect the cert argument */
5676       while (isspace(*s)) s++;
5677       if (*s != '{')                                    /*}*/
5678         {
5679         expand_string_message = US"missing '{' for cert variable arg of certextract";
5680         goto EXPAND_FAILED_CURLY;
5681         }
5682       if (*++s != '$')
5683         {
5684         expand_string_message = US"second argument of \"certextract\" must "
5685           "be a certificate variable";
5686         goto EXPAND_FAILED;
5687         }
5688       sub[1] = expand_string_internal(s+1, TRUE, &s, skipping, FALSE, &resetok);
5689       if (!sub[1])     goto EXPAND_FAILED;              /*{*/
5690       if (*s++ != '}')
5691         {
5692         expand_string_message = US"missing '}' closing cert variable arg of certextract";
5693         goto EXPAND_FAILED_CURLY;
5694         }
5695
5696       if (skipping)
5697         lookup_value = NULL;
5698       else
5699         {
5700         lookup_value = expand_getcertele(sub[0], sub[1]);
5701         if (*expand_string_message) goto EXPAND_FAILED;
5702         }
5703       switch(process_yesno(
5704                skipping,                     /* were previously skipping */
5705                lookup_value != NULL,         /* success/failure indicator */
5706                save_lookup_value,            /* value to reset for string2 */
5707                &s,                           /* input pointer */
5708                &yield,                       /* output pointer */
5709                &size,                        /* output size */
5710                &ptr,                         /* output current point */
5711                US"certextract",              /* condition type */
5712                &resetok))
5713         {
5714         case 1: goto EXPAND_FAILED;          /* when all is well, the */
5715         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
5716         }
5717
5718       restore_expand_strings(save_expand_nmax, save_expand_nstring,
5719         save_expand_nlength);
5720       continue;
5721       }
5722 #endif  /*SUPPORT_TLS*/
5723
5724     /* Handle list operations */
5725
5726     case EITEM_FILTER:
5727     case EITEM_MAP:
5728     case EITEM_REDUCE:
5729       {
5730       int sep = 0;
5731       int save_ptr = ptr;
5732       uschar outsep[2] = { '\0', '\0' };
5733       const uschar *list, *expr, *temp;
5734       uschar *save_iterate_item = iterate_item;
5735       uschar *save_lookup_value = lookup_value;
5736
5737       while (isspace(*s)) s++;
5738       if (*s++ != '{')
5739         {
5740         expand_string_message =
5741           string_sprintf("missing '{' for first arg of %s", name);
5742         goto EXPAND_FAILED_CURLY;
5743         }
5744
5745       list = expand_string_internal(s, TRUE, &s, skipping, TRUE, &resetok);
5746       if (list == NULL) goto EXPAND_FAILED;
5747       if (*s++ != '}')
5748         {
5749         expand_string_message =
5750           string_sprintf("missing '}' closing first arg of %s", name);
5751         goto EXPAND_FAILED_CURLY;
5752         }
5753
5754       if (item_type == EITEM_REDUCE)
5755         {
5756         uschar * t;
5757         while (isspace(*s)) s++;
5758         if (*s++ != '{')
5759           {
5760           expand_string_message = US"missing '{' for second arg of reduce";
5761           goto EXPAND_FAILED_CURLY;
5762           }
5763         t = expand_string_internal(s, TRUE, &s, skipping, TRUE, &resetok);
5764         if (!t) goto EXPAND_FAILED;
5765         lookup_value = t;
5766         if (*s++ != '}')
5767           {
5768           expand_string_message = US"missing '}' closing second arg of reduce";
5769           goto EXPAND_FAILED_CURLY;
5770           }
5771         }
5772
5773       while (isspace(*s)) s++;
5774       if (*s++ != '{')
5775         {
5776         expand_string_message =
5777           string_sprintf("missing '{' for last arg of %s", name);
5778         goto EXPAND_FAILED_CURLY;
5779         }
5780
5781       expr = s;
5782
5783       /* For EITEM_FILTER, call eval_condition once, with result discarded (as
5784       if scanning a "false" part). This allows us to find the end of the
5785       condition, because if the list is empty, we won't actually evaluate the
5786       condition for real. For EITEM_MAP and EITEM_REDUCE, do the same, using
5787       the normal internal expansion function. */
5788
5789       if (item_type == EITEM_FILTER)
5790         {
5791         temp = eval_condition(expr, &resetok, NULL);
5792         if (temp != NULL) s = temp;
5793         }
5794       else
5795         temp = expand_string_internal(s, TRUE, &s, TRUE, TRUE, &resetok);
5796
5797       if (temp == NULL)
5798         {
5799         expand_string_message = string_sprintf("%s inside \"%s\" item",
5800           expand_string_message, name);
5801         goto EXPAND_FAILED;
5802         }
5803
5804       while (isspace(*s)) s++;
5805       if (*s++ != '}')
5806         {                                               /*{*/
5807         expand_string_message = string_sprintf("missing } at end of condition "
5808           "or expression inside \"%s\"", name);
5809         goto EXPAND_FAILED;
5810         }
5811
5812       while (isspace(*s)) s++;                          /*{*/
5813       if (*s++ != '}')
5814         {                                               /*{*/
5815         expand_string_message = string_sprintf("missing } at end of \"%s\"",
5816           name);
5817         goto EXPAND_FAILED;
5818         }
5819
5820       /* If we are skipping, we can now just move on to the next item. When
5821       processing for real, we perform the iteration. */
5822
5823       if (skipping) continue;
5824       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)))
5825         {
5826         *outsep = (uschar)sep;      /* Separator as a string */
5827
5828         DEBUG(D_expand) debug_printf_indent("%s: $item = '%s'  $value = '%s'\n",
5829                           name, iterate_item, lookup_value);
5830
5831         if (item_type == EITEM_FILTER)
5832           {
5833           BOOL condresult;
5834           if (eval_condition(expr, &resetok, &condresult) == NULL)
5835             {
5836             iterate_item = save_iterate_item;
5837             lookup_value = save_lookup_value;
5838             expand_string_message = string_sprintf("%s inside \"%s\" condition",
5839               expand_string_message, name);
5840             goto EXPAND_FAILED;
5841             }
5842           DEBUG(D_expand) debug_printf_indent("%s: condition is %s\n", name,
5843             condresult? "true":"false");
5844           if (condresult)
5845             temp = iterate_item;    /* TRUE => include this item */
5846           else
5847             continue;               /* FALSE => skip this item */
5848           }
5849
5850         /* EITEM_MAP and EITEM_REDUCE */
5851
5852         else
5853           {
5854           uschar * t = expand_string_internal(expr, TRUE, NULL, skipping, TRUE, &resetok);
5855           temp = t;
5856           if (temp == NULL)
5857             {
5858             iterate_item = save_iterate_item;
5859             expand_string_message = string_sprintf("%s inside \"%s\" item",
5860               expand_string_message, name);
5861             goto EXPAND_FAILED;
5862             }
5863           if (item_type == EITEM_REDUCE)
5864             {
5865             lookup_value = t;         /* Update the value of $value */
5866             continue;                 /* and continue the iteration */
5867             }
5868           }
5869
5870         /* We reach here for FILTER if the condition is true, always for MAP,
5871         and never for REDUCE. The value in "temp" is to be added to the output
5872         list that is being created, ensuring that any occurrences of the
5873         separator character are doubled. Unless we are dealing with the first
5874         item of the output list, add in a space if the new item begins with the
5875         separator character, or is an empty string. */
5876
5877         if (ptr != save_ptr && (temp[0] == *outsep || temp[0] == 0))
5878           yield = string_catn(yield, &size, &ptr, US" ", 1);
5879
5880         /* Add the string in "temp" to the output list that we are building,
5881         This is done in chunks by searching for the separator character. */
5882
5883         for (;;)
5884           {
5885           size_t seglen = Ustrcspn(temp, outsep);
5886
5887           yield = string_catn(yield, &size, &ptr, temp, seglen + 1);
5888
5889           /* If we got to the end of the string we output one character
5890           too many; backup and end the loop. Otherwise arrange to double the
5891           separator. */
5892
5893           if (temp[seglen] == '\0') { ptr--; break; }
5894           yield = string_catn(yield, &size, &ptr, outsep, 1);
5895           temp += seglen + 1;
5896           }
5897
5898         /* Output a separator after the string: we will remove the redundant
5899         final one at the end. */
5900
5901         yield = string_catn(yield, &size, &ptr, outsep, 1);
5902         }   /* End of iteration over the list loop */
5903
5904       /* REDUCE has generated no output above: output the final value of
5905       $value. */
5906
5907       if (item_type == EITEM_REDUCE)
5908         {
5909         yield = string_cat(yield, &size, &ptr, lookup_value);
5910         lookup_value = save_lookup_value;  /* Restore $value */
5911         }
5912
5913       /* FILTER and MAP generate lists: if they have generated anything, remove
5914       the redundant final separator. Even though an empty item at the end of a
5915       list does not count, this is tidier. */
5916
5917       else if (ptr != save_ptr) ptr--;
5918
5919       /* Restore preserved $item */
5920
5921       iterate_item = save_iterate_item;
5922       continue;
5923       }
5924
5925     case EITEM_SORT:
5926       {
5927       int sep = 0;
5928       const uschar *srclist, *cmp, *xtract;
5929       uschar *srcitem;
5930       const uschar *dstlist = NULL, *dstkeylist = NULL;
5931       uschar * tmp;
5932       uschar *save_iterate_item = iterate_item;
5933
5934       while (isspace(*s)) s++;
5935       if (*s++ != '{')
5936         {
5937         expand_string_message = US"missing '{' for list arg of sort";
5938         goto EXPAND_FAILED_CURLY;
5939         }
5940
5941       srclist = expand_string_internal(s, TRUE, &s, skipping, TRUE, &resetok);
5942       if (!srclist) goto EXPAND_FAILED;
5943       if (*s++ != '}')
5944         {
5945         expand_string_message = US"missing '}' closing list arg of sort";
5946         goto EXPAND_FAILED_CURLY;
5947         }
5948
5949       while (isspace(*s)) s++;
5950       if (*s++ != '{')
5951         {
5952         expand_string_message = US"missing '{' for comparator arg of sort";
5953         goto EXPAND_FAILED_CURLY;
5954         }
5955
5956       cmp = expand_string_internal(s, TRUE, &s, skipping, FALSE, &resetok);
5957       if (!cmp) goto EXPAND_FAILED;
5958       if (*s++ != '}')
5959         {
5960         expand_string_message = US"missing '}' closing comparator arg of sort";
5961         goto EXPAND_FAILED_CURLY;
5962         }
5963
5964       while (isspace(*s)) s++;
5965       if (*s++ != '{')
5966         {
5967         expand_string_message = US"missing '{' for extractor arg of sort";
5968         goto EXPAND_FAILED_CURLY;
5969         }
5970
5971       xtract = s;
5972       tmp = expand_string_internal(s, TRUE, &s, TRUE, TRUE, &resetok);
5973       if (!tmp) goto EXPAND_FAILED;
5974       xtract = string_copyn(xtract, s - xtract);
5975
5976       if (*s++ != '}')
5977         {
5978         expand_string_message = US"missing '}' closing extractor arg of sort";
5979         goto EXPAND_FAILED_CURLY;
5980         }
5981                                                         /*{*/
5982       if (*s++ != '}')
5983         {                                               /*{*/
5984         expand_string_message = US"missing } at end of \"sort\"";
5985         goto EXPAND_FAILED;
5986         }
5987
5988       if (skipping) continue;
5989
5990       while ((srcitem = string_nextinlist(&srclist, &sep, NULL, 0)))
5991         {
5992         uschar * dstitem;
5993         uschar * newlist = NULL;
5994         uschar * newkeylist = NULL;
5995         uschar * srcfield;
5996
5997         DEBUG(D_expand) debug_printf_indent("%s: $item = \"%s\"\n", name, srcitem);
5998
5999         /* extract field for comparisons */
6000         iterate_item = srcitem;
6001         if (  !(srcfield = expand_string_internal(xtract, FALSE, NULL, FALSE,
6002                                           TRUE, &resetok))
6003            || !*srcfield)
6004           {
6005           expand_string_message = string_sprintf(
6006               "field-extract in sort: \"%s\"", xtract);
6007           goto EXPAND_FAILED;
6008           }
6009
6010         /* Insertion sort */
6011
6012         /* copy output list until new-item < list-item */
6013         while ((dstitem = string_nextinlist(&dstlist, &sep, NULL, 0)))
6014           {
6015           uschar * dstfield;
6016           uschar * expr;
6017           BOOL before;
6018
6019           /* field for comparison */
6020           if (!(dstfield = string_nextinlist(&dstkeylist, &sep, NULL, 0)))
6021             goto sort_mismatch;
6022
6023           /* build and run condition string */
6024           expr = string_sprintf("%s{%s}{%s}", cmp, srcfield, dstfield);
6025
6026           DEBUG(D_expand) debug_printf_indent("%s: cond = \"%s\"\n", name, expr);
6027           if (!eval_condition(expr, &resetok, &before))
6028             {
6029             expand_string_message = string_sprintf("comparison in sort: %s",
6030                 expr);
6031             goto EXPAND_FAILED;
6032             }
6033
6034           if (before)
6035             {
6036             /* New-item sorts before this dst-item.  Append new-item,
6037             then dst-item, then remainder of dst list. */
6038
6039             newlist = string_append_listele(newlist, sep, srcitem);
6040             newkeylist = string_append_listele(newkeylist, sep, srcfield);
6041             srcitem = NULL;
6042
6043             newlist = string_append_listele(newlist, sep, dstitem);
6044             newkeylist = string_append_listele(newkeylist, sep, dstfield);
6045
6046             while ((dstitem = string_nextinlist(&dstlist, &sep, NULL, 0)))
6047               {
6048               if (!(dstfield = string_nextinlist(&dstkeylist, &sep, NULL, 0)))
6049                 goto sort_mismatch;
6050               newlist = string_append_listele(newlist, sep, dstitem);
6051               newkeylist = string_append_listele(newkeylist, sep, dstfield);
6052               }
6053
6054             break;
6055             }
6056
6057           newlist = string_append_listele(newlist, sep, dstitem);
6058           newkeylist = string_append_listele(newkeylist, sep, dstfield);
6059           }
6060
6061         /* If we ran out of dstlist without consuming srcitem, append it */
6062         if (srcitem)
6063           {
6064           newlist = string_append_listele(newlist, sep, srcitem);
6065           newkeylist = string_append_listele(newkeylist, sep, srcfield);
6066           }
6067
6068         dstlist = newlist;
6069         dstkeylist = newkeylist;
6070
6071         DEBUG(D_expand) debug_printf_indent("%s: dstlist = \"%s\"\n", name, dstlist);
6072         DEBUG(D_expand) debug_printf_indent("%s: dstkeylist = \"%s\"\n", name, dstkeylist);
6073         }
6074
6075       if (dstlist)
6076         yield = string_cat(yield, &size, &ptr, dstlist);
6077
6078       /* Restore preserved $item */
6079       iterate_item = save_iterate_item;
6080       continue;
6081
6082       sort_mismatch:
6083         expand_string_message = US"Internal error in sort (list mismatch)";
6084         goto EXPAND_FAILED;
6085       }
6086
6087
6088     /* If ${dlfunc } support is configured, handle calling dynamically-loaded
6089     functions, unless locked out at this time. Syntax is ${dlfunc{file}{func}}
6090     or ${dlfunc{file}{func}{arg}} or ${dlfunc{file}{func}{arg1}{arg2}} or up to
6091     a maximum of EXPAND_DLFUNC_MAX_ARGS arguments (defined below). */
6092
6093     #define EXPAND_DLFUNC_MAX_ARGS 8
6094
6095     case EITEM_DLFUNC:
6096 #ifndef EXPAND_DLFUNC
6097       expand_string_message = US"\"${dlfunc\" encountered, but this facility "  /*}*/
6098         "is not included in this binary";
6099       goto EXPAND_FAILED;
6100
6101 #else   /* EXPAND_DLFUNC */
6102       {
6103       tree_node *t;
6104       exim_dlfunc_t *func;
6105       uschar *result;
6106       int status, argc;
6107       uschar *argv[EXPAND_DLFUNC_MAX_ARGS + 3];
6108
6109       if ((expand_forbid & RDO_DLFUNC) != 0)
6110         {
6111         expand_string_message =
6112           US"dynamically-loaded functions are not permitted";
6113         goto EXPAND_FAILED;
6114         }
6115
6116       switch(read_subs(argv, EXPAND_DLFUNC_MAX_ARGS + 2, 2, &s, skipping,
6117            TRUE, US"dlfunc", &resetok))
6118         {
6119         case 1: goto EXPAND_FAILED_CURLY;
6120         case 2:
6121         case 3: goto EXPAND_FAILED;
6122         }
6123
6124       /* If skipping, we don't actually do anything */
6125
6126       if (skipping) continue;
6127
6128       /* Look up the dynamically loaded object handle in the tree. If it isn't
6129       found, dlopen() the file and put the handle in the tree for next time. */
6130
6131       t = tree_search(dlobj_anchor, argv[0]);
6132       if (t == NULL)
6133         {
6134         void *handle = dlopen(CS argv[0], RTLD_LAZY);
6135         if (handle == NULL)
6136           {
6137           expand_string_message = string_sprintf("dlopen \"%s\" failed: %s",
6138             argv[0], dlerror());
6139           log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
6140           goto EXPAND_FAILED;
6141           }
6142         t = store_get_perm(sizeof(tree_node) + Ustrlen(argv[0]));
6143         Ustrcpy(t->name, argv[0]);
6144         t->data.ptr = handle;
6145         (void)tree_insertnode(&dlobj_anchor, t);
6146         }
6147
6148       /* Having obtained the dynamically loaded object handle, look up the
6149       function pointer. */
6150
6151       func = (exim_dlfunc_t *)dlsym(t->data.ptr, CS argv[1]);
6152       if (func == NULL)
6153         {
6154         expand_string_message = string_sprintf("dlsym \"%s\" in \"%s\" failed: "
6155           "%s", argv[1], argv[0], dlerror());
6156         log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
6157         goto EXPAND_FAILED;
6158         }
6159
6160       /* Call the function and work out what to do with the result. If it
6161       returns OK, we have a replacement string; if it returns DEFER then
6162       expansion has failed in a non-forced manner; if it returns FAIL then
6163       failure was forced; if it returns ERROR or any other value there's a
6164       problem, so panic slightly. In any case, assume that the function has
6165       side-effects on the store that must be preserved. */
6166
6167       resetok = FALSE;
6168       result = NULL;
6169       for (argc = 0; argv[argc] != NULL; argc++);
6170       status = func(&result, argc - 2, &argv[2]);
6171       if(status == OK)
6172         {
6173         if (result == NULL) result = US"";
6174         yield = string_cat(yield, &size, &ptr, result);
6175         continue;
6176         }
6177       else
6178         {
6179         expand_string_message = result == NULL ? US"(no message)" : result;
6180         if(status == FAIL_FORCED) expand_string_forcedfail = TRUE;
6181           else if(status != FAIL)
6182             log_write(0, LOG_MAIN|LOG_PANIC, "dlfunc{%s}{%s} failed (%d): %s",
6183               argv[0], argv[1], status, expand_string_message);
6184         goto EXPAND_FAILED;
6185         }
6186       }
6187 #endif /* EXPAND_DLFUNC */
6188
6189     case EITEM_ENV:     /* ${env {name} {val_if_found} {val_if_unfound}} */
6190       {
6191       uschar * key;
6192       uschar *save_lookup_value = lookup_value;
6193
6194       while (isspace(*s)) s++;
6195       if (*s != '{')                                    /*}*/
6196         goto EXPAND_FAILED;
6197
6198       key = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
6199       if (!key) goto EXPAND_FAILED;                     /*{*/
6200       if (*s++ != '}')
6201         {
6202         expand_string_message = US"missing '{' for name arg of env";
6203         goto EXPAND_FAILED_CURLY;
6204         }
6205
6206       lookup_value = US getenv(CS key);
6207
6208       switch(process_yesno(
6209                skipping,                     /* were previously skipping */
6210                lookup_value != NULL,         /* success/failure indicator */
6211                save_lookup_value,            /* value to reset for string2 */
6212                &s,                           /* input pointer */
6213                &yield,                       /* output pointer */
6214                &size,                        /* output size */
6215                &ptr,                         /* output current point */
6216                US"env",                      /* condition type */
6217                &resetok))
6218         {
6219         case 1: goto EXPAND_FAILED;          /* when all is well, the */
6220         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
6221         }
6222       continue;
6223       }
6224     }   /* EITEM_* switch */
6225
6226   /* Control reaches here if the name is not recognized as one of the more
6227   complicated expansion items. Check for the "operator" syntax (name terminated
6228   by a colon). Some of the operators have arguments, separated by _ from the
6229   name. */
6230
6231   if (*s == ':')
6232     {
6233     int c;
6234     uschar *arg = NULL;
6235     uschar *sub;
6236     var_entry *vp = NULL;
6237
6238     /* Owing to an historical mis-design, an underscore may be part of the
6239     operator name, or it may introduce arguments.  We therefore first scan the
6240     table of names that contain underscores. If there is no match, we cut off
6241     the arguments and then scan the main table. */
6242
6243     if ((c = chop_match(name, op_table_underscore,
6244                         nelem(op_table_underscore))) < 0)
6245       {
6246       arg = Ustrchr(name, '_');
6247       if (arg != NULL) *arg = 0;
6248       c = chop_match(name, op_table_main, nelem(op_table_main));
6249       if (c >= 0) c += nelem(op_table_underscore);
6250       if (arg != NULL) *arg++ = '_';   /* Put back for error messages */
6251       }
6252
6253     /* Deal specially with operators that might take a certificate variable
6254     as we do not want to do the usual expansion. For most, expand the string.*/
6255     switch(c)
6256       {
6257 #ifdef SUPPORT_TLS
6258       case EOP_MD5:
6259       case EOP_SHA1:
6260       case EOP_SHA256:
6261       case EOP_BASE64:
6262         if (s[1] == '$')
6263           {
6264           const uschar * s1 = s;
6265           sub = expand_string_internal(s+2, TRUE, &s1, skipping,
6266                   FALSE, &resetok);
6267           if (!sub)       goto EXPAND_FAILED;           /*{*/
6268           if (*s1 != '}')
6269             {
6270             expand_string_message =
6271               string_sprintf("missing '}' closing cert arg of %s", name);
6272             goto EXPAND_FAILED_CURLY;
6273             }
6274           if ((vp = find_var_ent(sub)) && vp->type == vtype_cert)
6275             {
6276             s = s1+1;
6277             break;
6278             }
6279           vp = NULL;
6280           }
6281         /*FALLTHROUGH*/
6282 #endif
6283       default:
6284         sub = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, &resetok);
6285         if (!sub) goto EXPAND_FAILED;
6286         s++;
6287         break;
6288       }
6289
6290     /* If we are skipping, we don't need to perform the operation at all.
6291     This matters for operations like "mask", because the data may not be
6292     in the correct format when skipping. For example, the expression may test
6293     for the existence of $sender_host_address before trying to mask it. For
6294     other operations, doing them may not fail, but it is a waste of time. */
6295
6296     if (skipping && c >= 0) continue;
6297
6298     /* Otherwise, switch on the operator type */
6299
6300     switch(c)
6301       {
6302       case EOP_BASE32:
6303         {
6304         uschar *t;
6305         unsigned long int n = Ustrtoul(sub, &t, 10);
6306         uschar * s = NULL;
6307         int sz = 0, i = 0;
6308
6309         if (*t != 0)
6310           {
6311           expand_string_message = string_sprintf("argument for base32 "
6312             "operator is \"%s\", which is not a decimal number", sub);
6313           goto EXPAND_FAILED;
6314           }
6315         for ( ; n; n >>= 5)
6316           s = string_catn(s, &sz, &i, &base32_chars[n & 0x1f], 1);
6317
6318         while (i > 0) yield = string_catn(yield, &size, &ptr, &s[--i], 1);
6319         continue;
6320         }
6321
6322       case EOP_BASE32D:
6323         {
6324         uschar *tt = sub;
6325         unsigned long int n = 0;
6326         uschar * s;
6327         while (*tt)
6328           {
6329           uschar * t = Ustrchr(base32_chars, *tt++);
6330           if (t == NULL)
6331             {
6332             expand_string_message = string_sprintf("argument for base32d "
6333               "operator is \"%s\", which is not a base 32 number", sub);
6334             goto EXPAND_FAILED;
6335             }
6336           n = n * 32 + (t - base32_chars);
6337           }
6338         s = string_sprintf("%ld", n);
6339         yield = string_cat(yield, &size, &ptr, s);
6340         continue;
6341         }
6342
6343       case EOP_BASE62:
6344         {
6345         uschar *t;
6346         unsigned long int n = Ustrtoul(sub, &t, 10);
6347         if (*t != 0)
6348           {
6349           expand_string_message = string_sprintf("argument for base62 "
6350             "operator is \"%s\", which is not a decimal number", sub);
6351           goto EXPAND_FAILED;
6352           }
6353         t = string_base62(n);
6354         yield = string_cat(yield, &size, &ptr, t);
6355         continue;
6356         }
6357
6358       /* Note that for Darwin and Cygwin, BASE_62 actually has the value 36 */
6359
6360       case EOP_BASE62D:
6361         {
6362         uschar buf[16];
6363         uschar *tt = sub;
6364         unsigned long int n = 0;
6365         while (*tt != 0)
6366           {
6367           uschar *t = Ustrchr(base62_chars, *tt++);
6368           if (t == NULL)
6369             {
6370             expand_string_message = string_sprintf("argument for base62d "
6371               "operator is \"%s\", which is not a base %d number", sub,
6372               BASE_62);
6373             goto EXPAND_FAILED;
6374             }
6375           n = n * BASE_62 + (t - base62_chars);
6376           }
6377         (void)sprintf(CS buf, "%ld", n);
6378         yield = string_cat(yield, &size, &ptr, buf);
6379         continue;
6380         }
6381
6382       case EOP_EXPAND:
6383         {
6384         uschar *expanded = expand_string_internal(sub, FALSE, NULL, skipping, TRUE, &resetok);
6385         if (expanded == NULL)
6386           {
6387           expand_string_message =
6388             string_sprintf("internal expansion of \"%s\" failed: %s", sub,
6389               expand_string_message);
6390           goto EXPAND_FAILED;
6391           }
6392         yield = string_cat(yield, &size, &ptr, expanded);
6393         continue;
6394         }
6395
6396       case EOP_LC:
6397         {
6398         int count = 0;
6399         uschar *t = sub - 1;
6400         while (*(++t) != 0) { *t = tolower(*t); count++; }
6401         yield = string_catn(yield, &size, &ptr, sub, count);
6402         continue;
6403         }
6404
6405       case EOP_UC:
6406         {
6407         int count = 0;
6408         uschar *t = sub - 1;
6409         while (*(++t) != 0) { *t = toupper(*t); count++; }
6410         yield = string_catn(yield, &size, &ptr, sub, count);
6411         continue;
6412         }
6413
6414       case EOP_MD5:
6415 #ifdef SUPPORT_TLS
6416         if (vp && *(void **)vp->value)
6417           {
6418           uschar * cp = tls_cert_fprt_md5(*(void **)vp->value);
6419           yield = string_cat(yield, &size, &ptr, cp);
6420           }
6421         else
6422 #endif
6423           {
6424           md5 base;
6425           uschar digest[16];
6426           int j;
6427           char st[33];
6428           md5_start(&base);
6429           md5_end(&base, sub, Ustrlen(sub), digest);
6430           for(j = 0; j < 16; j++) sprintf(st+2*j, "%02x", digest[j]);
6431           yield = string_cat(yield, &size, &ptr, US st);
6432           }
6433         continue;
6434
6435       case EOP_SHA1:
6436 #ifdef SUPPORT_TLS
6437         if (vp && *(void **)vp->value)
6438           {
6439           uschar * cp = tls_cert_fprt_sha1(*(void **)vp->value);
6440           yield = string_cat(yield, &size, &ptr, cp);
6441           }
6442         else
6443 #endif
6444           {
6445           hctx h;
6446           uschar digest[20];
6447           int j;
6448           char st[41];
6449           sha1_start(&h);
6450           sha1_end(&h, sub, Ustrlen(sub), digest);
6451           for(j = 0; j < 20; j++) sprintf(st+2*j, "%02X", digest[j]);
6452           yield = string_catn(yield, &size, &ptr, US st, 40);
6453           }
6454         continue;
6455
6456       case EOP_SHA256:
6457 #ifdef EXIM_HAVE_SHA2
6458         if (vp && *(void **)vp->value)
6459           {
6460           uschar * cp = tls_cert_fprt_sha256(*(void **)vp->value);
6461           yield = string_cat(yield, &size, &ptr, cp);
6462           }
6463         else
6464           {
6465           hctx h;
6466           blob b;
6467           char st[3];
6468
6469           if (!exim_sha_init(&h, HASH_SHA256))
6470             {
6471             expand_string_message = US"unrecognised sha256 variant";
6472             goto EXPAND_FAILED;
6473             }
6474           exim_sha_update(&h, sub, Ustrlen(sub));
6475           exim_sha_finish(&h, &b);
6476           while (b.len-- > 0)
6477             {
6478             sprintf(st, "%02X", *b.data++);
6479             yield = string_catn(yield, &size, &ptr, US st, 2);
6480             }
6481           }
6482 #else
6483           expand_string_message = US"sha256 only supported with TLS";
6484 #endif
6485         continue;
6486
6487       case EOP_SHA3:
6488 #ifdef EXIM_HAVE_SHA3
6489         {
6490         hctx h;
6491         blob b;
6492         char st[3];
6493         hashmethod m = !arg ? HASH_SHA3_256
6494           : Ustrcmp(arg, "224") == 0 ? HASH_SHA3_224
6495           : Ustrcmp(arg, "256") == 0 ? HASH_SHA3_256
6496           : Ustrcmp(arg, "384") == 0 ? HASH_SHA3_384
6497           : Ustrcmp(arg, "512") == 0 ? HASH_SHA3_512
6498           : HASH_BADTYPE;
6499
6500         if (m == HASH_BADTYPE || !exim_sha_init(&h, m))
6501           {
6502           expand_string_message = US"unrecognised sha3 variant";
6503           goto EXPAND_FAILED;
6504           }
6505
6506         exim_sha_update(&h, sub, Ustrlen(sub));
6507         exim_sha_finish(&h, &b);
6508         while (b.len-- > 0)
6509           {
6510           sprintf(st, "%02X", *b.data++);
6511           yield = string_catn(yield, &size, &ptr, US st, 2);
6512           }
6513         }
6514         continue;
6515 #else
6516         expand_string_message = US"sha3 only supported with GnuTLS 3.5.0 +";
6517         goto EXPAND_FAILED;
6518 #endif
6519
6520       /* Convert hex encoding to base64 encoding */
6521
6522       case EOP_HEX2B64:
6523         {
6524         int c = 0;
6525         int b = -1;
6526         uschar *in = sub;
6527         uschar *out = sub;
6528         uschar *enc;
6529
6530         for (enc = sub; *enc != 0; enc++)
6531           {
6532           if (!isxdigit(*enc))
6533             {
6534             expand_string_message = string_sprintf("\"%s\" is not a hex "
6535               "string", sub);
6536             goto EXPAND_FAILED;
6537             }
6538           c++;
6539           }
6540
6541         if ((c & 1) != 0)
6542           {
6543           expand_string_message = string_sprintf("\"%s\" contains an odd "
6544             "number of characters", sub);
6545           goto EXPAND_FAILED;
6546           }
6547
6548         while ((c = *in++) != 0)
6549           {
6550           if (isdigit(c)) c -= '0';
6551           else c = toupper(c) - 'A' + 10;
6552           if (b == -1)
6553             {
6554             b = c << 4;
6555             }
6556           else
6557             {
6558             *out++ = b | c;
6559             b = -1;
6560             }
6561           }
6562
6563         enc = b64encode(sub, out - sub);
6564         yield = string_cat(yield, &size, &ptr, enc);
6565         continue;
6566         }
6567
6568       /* Convert octets outside 0x21..0x7E to \xXX form */
6569
6570       case EOP_HEXQUOTE:
6571         {
6572         uschar *t = sub - 1;
6573         while (*(++t) != 0)
6574           {
6575           if (*t < 0x21 || 0x7E < *t)
6576             yield = string_catn(yield, &size, &ptr,
6577               string_sprintf("\\x%02x", *t), 4);
6578           else
6579             yield = string_catn(yield, &size, &ptr, t, 1);
6580           }
6581         continue;
6582         }
6583
6584       /* count the number of list elements */
6585
6586       case EOP_LISTCOUNT:
6587         {
6588         int cnt = 0;
6589         int sep = 0;
6590         uschar * cp;
6591         uschar buffer[256];
6592
6593         while (string_nextinlist(CUSS &sub, &sep, buffer, sizeof(buffer)) != NULL) cnt++;
6594         cp = string_sprintf("%d", cnt);
6595         yield = string_cat(yield, &size, &ptr, cp);
6596         continue;
6597         }
6598
6599       /* expand a named list given the name */
6600       /* handles nested named lists; requotes as colon-sep list */
6601
6602       case EOP_LISTNAMED:
6603         {
6604         tree_node *t = NULL;
6605         const uschar * list;
6606         int sep = 0;
6607         uschar * item;
6608         uschar * suffix = US"";
6609         BOOL needsep = FALSE;
6610         uschar buffer[256];
6611
6612         if (*sub == '+') sub++;
6613         if (arg == NULL)        /* no-argument version */
6614           {
6615           if (!(t = tree_search(addresslist_anchor, sub)) &&
6616               !(t = tree_search(domainlist_anchor,  sub)) &&
6617               !(t = tree_search(hostlist_anchor,    sub)))
6618             t = tree_search(localpartlist_anchor, sub);
6619           }
6620         else switch(*arg)       /* specific list-type version */
6621           {
6622           case 'a': t = tree_search(addresslist_anchor,   sub); suffix = US"_a"; break;
6623           case 'd': t = tree_search(domainlist_anchor,    sub); suffix = US"_d"; break;
6624           case 'h': t = tree_search(hostlist_anchor,      sub); suffix = US"_h"; break;
6625           case 'l': t = tree_search(localpartlist_anchor, sub); suffix = US"_l"; break;
6626           default:
6627             expand_string_message = string_sprintf("bad suffix on \"list\" operator");
6628             goto EXPAND_FAILED;
6629           }
6630
6631         if(!t)
6632           {
6633           expand_string_message = string_sprintf("\"%s\" is not a %snamed list",
6634             sub, !arg?""
6635               : *arg=='a'?"address "
6636               : *arg=='d'?"domain "
6637               : *arg=='h'?"host "
6638               : *arg=='l'?"localpart "
6639               : 0);
6640           goto EXPAND_FAILED;
6641           }
6642
6643         list = ((namedlist_block *)(t->data.ptr))->string;
6644
6645         while ((item = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
6646           {
6647           uschar * buf = US" : ";
6648           if (needsep)
6649             yield = string_catn(yield, &size, &ptr, buf, 3);
6650           else
6651             needsep = TRUE;
6652
6653           if (*item == '+')     /* list item is itself a named list */
6654             {
6655             uschar * sub = string_sprintf("${listnamed%s:%s}", suffix, item);
6656             item = expand_string_internal(sub, FALSE, NULL, FALSE, TRUE, &resetok);
6657             }
6658           else if (sep != ':')  /* item from non-colon-sep list, re-quote for colon list-separator */
6659             {
6660             char * cp;
6661             char tok[3];
6662             tok[0] = sep; tok[1] = ':'; tok[2] = 0;
6663             while ((cp= strpbrk((const char *)item, tok)))
6664               {
6665               yield = string_catn(yield, &size, &ptr, item, cp-(char *)item);
6666               if (*cp++ == ':') /* colon in a non-colon-sep list item, needs doubling */
6667                 {
6668                 yield = string_catn(yield, &size, &ptr, US"::", 2);
6669                 item = (uschar *)cp;
6670                 }
6671               else              /* sep in item; should already be doubled; emit once */
6672                 {
6673                 yield = string_catn(yield, &size, &ptr, (uschar *)tok, 1);
6674                 if (*cp == sep) cp++;
6675                 item = (uschar *)cp;
6676                 }
6677               }
6678             }
6679           yield = string_cat(yield, &size, &ptr, item);
6680           }
6681         continue;
6682         }
6683
6684       /* mask applies a mask to an IP address; for example the result of
6685       ${mask:131.111.10.206/28} is 131.111.10.192/28. */
6686
6687       case EOP_MASK:
6688         {
6689         int count;
6690         uschar *endptr;
6691         int binary[4];
6692         int mask, maskoffset;
6693         int type = string_is_ip_address(sub, &maskoffset);
6694         uschar buffer[64];
6695
6696         if (type == 0)
6697           {
6698           expand_string_message = string_sprintf("\"%s\" is not an IP address",
6699            sub);
6700           goto EXPAND_FAILED;
6701           }
6702
6703         if (maskoffset == 0)
6704           {
6705           expand_string_message = string_sprintf("missing mask value in \"%s\"",
6706             sub);
6707           goto EXPAND_FAILED;
6708           }
6709
6710         mask = Ustrtol(sub + maskoffset + 1, &endptr, 10);
6711
6712         if (*endptr != 0 || mask < 0 || mask > ((type == 4)? 32 : 128))
6713           {
6714           expand_string_message = string_sprintf("mask value too big in \"%s\"",
6715             sub);
6716           goto EXPAND_FAILED;
6717           }
6718
6719         /* Convert the address to binary integer(s) and apply the mask */
6720
6721         sub[maskoffset] = 0;
6722         count = host_aton(sub, binary);
6723         host_mask(count, binary, mask);
6724
6725         /* Convert to masked textual format and add to output. */
6726
6727         yield = string_catn(yield, &size, &ptr, buffer,
6728           host_nmtoa(count, binary, mask, buffer, '.'));
6729         continue;
6730         }
6731
6732       case EOP_IPV6NORM:
6733       case EOP_IPV6DENORM:
6734         {
6735         int type = string_is_ip_address(sub, NULL);
6736         int binary[4];
6737         uschar buffer[44];
6738
6739         switch (type)
6740           {
6741           case 6:
6742             (void) host_aton(sub, binary);
6743             break;
6744
6745           case 4:       /* convert to IPv4-mapped IPv6 */
6746             binary[0] = binary[1] = 0;
6747             binary[2] = 0x0000ffff;
6748             (void) host_aton(sub, binary+3);
6749             break;
6750
6751           case 0:
6752             expand_string_message =
6753               string_sprintf("\"%s\" is not an IP address", sub);
6754             goto EXPAND_FAILED;
6755           }
6756
6757         yield = string_catn(yield, &size, &ptr, buffer,
6758                   c == EOP_IPV6NORM
6759                     ? ipv6_nmtoa(binary, buffer)
6760                     : host_nmtoa(4, binary, -1, buffer, ':')
6761                   );
6762         continue;
6763         }
6764
6765       case EOP_ADDRESS:
6766       case EOP_LOCAL_PART:
6767       case EOP_DOMAIN:
6768         {
6769         uschar * error;
6770         int start, end, domain;
6771         uschar * t = parse_extract_address(sub, &error, &start, &end, &domain,
6772           FALSE);
6773         if (t)
6774           if (c != EOP_DOMAIN)
6775             {
6776             if (c == EOP_LOCAL_PART && domain != 0) end = start + domain - 1;
6777             yield = string_catn(yield, &size, &ptr, sub+start, end-start);
6778             }
6779           else if (domain != 0)
6780             {
6781             domain += start;
6782             yield = string_catn(yield, &size, &ptr, sub+domain, end-domain);
6783             }
6784         continue;
6785         }
6786
6787       case EOP_ADDRESSES:
6788         {
6789         uschar outsep[2] = { ':', '\0' };
6790         uschar *address, *error;
6791         int save_ptr = ptr;
6792         int start, end, domain;  /* Not really used */
6793
6794         while (isspace(*sub)) sub++;
6795         if (*sub == '>') { *outsep = *++sub; ++sub; }
6796         parse_allow_group = TRUE;
6797
6798         for (;;)
6799           {
6800           uschar *p = parse_find_address_end(sub, FALSE);
6801           uschar saveend = *p;
6802           *p = '\0';
6803           address = parse_extract_address(sub, &error, &start, &end, &domain,
6804             FALSE);
6805           *p = saveend;
6806
6807           /* Add the address to the output list that we are building. This is
6808           done in chunks by searching for the separator character. At the
6809           start, unless we are dealing with the first address of the output
6810           list, add in a space if the new address begins with the separator
6811           character, or is an empty string. */
6812
6813           if (address != NULL)
6814             {
6815             if (ptr != save_ptr && address[0] == *outsep)
6816               yield = string_catn(yield, &size, &ptr, US" ", 1);
6817
6818             for (;;)
6819               {
6820               size_t seglen = Ustrcspn(address, outsep);
6821               yield = string_catn(yield, &size, &ptr, address, seglen + 1);
6822
6823               /* If we got to the end of the string we output one character
6824               too many. */
6825
6826               if (address[seglen] == '\0') { ptr--; break; }
6827               yield = string_catn(yield, &size, &ptr, outsep, 1);
6828               address += seglen + 1;
6829               }
6830
6831             /* Output a separator after the string: we will remove the
6832             redundant final one at the end. */
6833
6834             yield = string_catn(yield, &size, &ptr, outsep, 1);
6835             }
6836
6837           if (saveend == '\0') break;
6838           sub = p + 1;
6839           }
6840
6841         /* If we have generated anything, remove the redundant final
6842         separator. */
6843
6844         if (ptr != save_ptr) ptr--;
6845         parse_allow_group = FALSE;
6846         continue;
6847         }
6848
6849
6850       /* quote puts a string in quotes if it is empty or contains anything
6851       other than alphamerics, underscore, dot, or hyphen.
6852
6853       quote_local_part puts a string in quotes if RFC 2821/2822 requires it to
6854       be quoted in order to be a valid local part.
6855
6856       In both cases, newlines and carriage returns are converted into \n and \r
6857       respectively */
6858
6859       case EOP_QUOTE:
6860       case EOP_QUOTE_LOCAL_PART:
6861       if (arg == NULL)
6862         {
6863         BOOL needs_quote = (*sub == 0);      /* TRUE for empty string */
6864         uschar *t = sub - 1;
6865
6866         if (c == EOP_QUOTE)
6867           {
6868           while (!needs_quote && *(++t) != 0)
6869             needs_quote = !isalnum(*t) && !strchr("_-.", *t);
6870           }
6871         else  /* EOP_QUOTE_LOCAL_PART */
6872           {
6873           while (!needs_quote && *(++t) != 0)
6874             needs_quote = !isalnum(*t) &&
6875               strchr("!#$%&'*+-/=?^_`{|}~", *t) == NULL &&
6876               (*t != '.' || t == sub || t[1] == 0);
6877           }
6878
6879         if (needs_quote)
6880           {
6881           yield = string_catn(yield, &size, &ptr, US"\"", 1);
6882           t = sub - 1;
6883           while (*(++t) != 0)
6884             {
6885             if (*t == '\n')
6886               yield = string_catn(yield, &size, &ptr, US"\\n", 2);
6887             else if (*t == '\r')
6888               yield = string_catn(yield, &size, &ptr, US"\\r", 2);
6889             else
6890               {
6891               if (*t == '\\' || *t == '"')
6892                 yield = string_catn(yield, &size, &ptr, US"\\", 1);
6893               yield = string_catn(yield, &size, &ptr, t, 1);
6894               }
6895             }
6896           yield = string_catn(yield, &size, &ptr, US"\"", 1);
6897           }
6898         else yield = string_cat(yield, &size, &ptr, sub);
6899         continue;
6900         }
6901
6902       /* quote_lookuptype does lookup-specific quoting */
6903
6904       else
6905         {
6906         int n;
6907         uschar *opt = Ustrchr(arg, '_');
6908
6909         if (opt != NULL) *opt++ = 0;
6910
6911         n = search_findtype(arg, Ustrlen(arg));
6912         if (n < 0)
6913           {
6914           expand_string_message = search_error_message;
6915           goto EXPAND_FAILED;
6916           }
6917
6918         if (lookup_list[n]->quote != NULL)
6919           sub = (lookup_list[n]->quote)(sub, opt);
6920         else if (opt != NULL) sub = NULL;
6921
6922         if (sub == NULL)
6923           {
6924           expand_string_message = string_sprintf(
6925             "\"%s\" unrecognized after \"${quote_%s\"",
6926             opt, arg);
6927           goto EXPAND_FAILED;
6928           }
6929
6930         yield = string_cat(yield, &size, &ptr, sub);
6931         continue;
6932         }
6933
6934       /* rx quote sticks in \ before any non-alphameric character so that
6935       the insertion works in a regular expression. */
6936
6937       case EOP_RXQUOTE:
6938         {
6939         uschar *t = sub - 1;
6940         while (*(++t) != 0)
6941           {
6942           if (!isalnum(*t))
6943             yield = string_catn(yield, &size, &ptr, US"\\", 1);
6944           yield = string_catn(yield, &size, &ptr, t, 1);
6945           }
6946         continue;
6947         }
6948
6949       /* RFC 2047 encodes, assuming headers_charset (default ISO 8859-1) as
6950       prescribed by the RFC, if there are characters that need to be encoded */
6951
6952       case EOP_RFC2047:
6953         {
6954         uschar buffer[2048];
6955         const uschar *string = parse_quote_2047(sub, Ustrlen(sub), headers_charset,
6956           buffer, sizeof(buffer), FALSE);
6957         yield = string_cat(yield, &size, &ptr, string);
6958         continue;
6959         }
6960
6961       /* RFC 2047 decode */
6962
6963       case EOP_RFC2047D:
6964         {
6965         int len;
6966         uschar *error;
6967         uschar *decoded = rfc2047_decode(sub, check_rfc2047_length,
6968           headers_charset, '?', &len, &error);
6969         if (error != NULL)
6970           {
6971           expand_string_message = error;
6972           goto EXPAND_FAILED;
6973           }
6974         yield = string_catn(yield, &size, &ptr, decoded, len);
6975         continue;
6976         }
6977
6978       /* from_utf8 converts UTF-8 to 8859-1, turning non-existent chars into
6979       underscores */
6980
6981       case EOP_FROM_UTF8:
6982         {
6983         while (*sub != 0)
6984           {
6985           int c;
6986           uschar buff[4];
6987           GETUTF8INC(c, sub);
6988           if (c > 255) c = '_';
6989           buff[0] = c;
6990           yield = string_catn(yield, &size, &ptr, buff, 1);
6991           }
6992         continue;
6993         }
6994
6995           /* replace illegal UTF-8 sequences by replacement character  */
6996
6997       #define UTF8_REPLACEMENT_CHAR US"?"
6998
6999       case EOP_UTF8CLEAN:
7000         {
7001         int seq_len = 0, index = 0;
7002         int bytes_left = 0;
7003         long codepoint = -1;
7004         uschar seq_buff[4];                     /* accumulate utf-8 here */
7005
7006         while (*sub != 0)
7007           {
7008           int complete = 0;
7009           uschar c = *sub++;
7010
7011           if (bytes_left)
7012             {
7013             if ((c & 0xc0) != 0x80)
7014                     /* wrong continuation byte; invalidate all bytes */
7015               complete = 1; /* error */
7016             else
7017               {
7018               codepoint = (codepoint << 6) | (c & 0x3f);
7019               seq_buff[index++] = c;
7020               if (--bytes_left == 0)            /* codepoint complete */
7021                 if(codepoint > 0x10FFFF)        /* is it too large? */
7022                   complete = -1;        /* error (RFC3629 limit) */
7023                 else
7024                   {             /* finished; output utf-8 sequence */
7025                   yield = string_catn(yield, &size, &ptr, seq_buff, seq_len);
7026                   index = 0;
7027                   }
7028               }
7029             }
7030           else  /* no bytes left: new sequence */
7031             {
7032             if((c & 0x80) == 0) /* 1-byte sequence, US-ASCII, keep it */
7033               {
7034               yield = string_catn(yield, &size, &ptr, &c, 1);
7035               continue;
7036               }
7037             if((c & 0xe0) == 0xc0)              /* 2-byte sequence */
7038               {
7039               if(c == 0xc0 || c == 0xc1)        /* 0xc0 and 0xc1 are illegal */
7040                 complete = -1;
7041               else
7042                 {
7043                   bytes_left = 1;
7044                   codepoint = c & 0x1f;
7045                 }
7046               }
7047             else if((c & 0xf0) == 0xe0)         /* 3-byte sequence */
7048               {
7049               bytes_left = 2;
7050               codepoint = c & 0x0f;
7051               }
7052             else if((c & 0xf8) == 0xf0)         /* 4-byte sequence */
7053               {
7054               bytes_left = 3;
7055               codepoint = c & 0x07;
7056               }
7057             else        /* invalid or too long (RFC3629 allows only 4 bytes) */
7058               complete = -1;
7059
7060             seq_buff[index++] = c;
7061             seq_len = bytes_left + 1;
7062             }           /* if(bytes_left) */
7063
7064           if (complete != 0)
7065             {
7066             bytes_left = index = 0;
7067             yield = string_catn(yield, &size, &ptr, UTF8_REPLACEMENT_CHAR, 1);
7068             }
7069           if ((complete == 1) && ((c & 0x80) == 0))
7070                         /* ASCII character follows incomplete sequence */
7071               yield = string_catn(yield, &size, &ptr, &c, 1);
7072           }
7073         continue;
7074         }
7075
7076 #ifdef SUPPORT_I18N
7077       case EOP_UTF8_DOMAIN_TO_ALABEL:
7078         {
7079         uschar * error = NULL;
7080         uschar * s = string_domain_utf8_to_alabel(sub, &error);
7081         if (error)
7082           {
7083           expand_string_message = string_sprintf(
7084             "error converting utf8 (%s) to alabel: %s",
7085             string_printing(sub), error);
7086           goto EXPAND_FAILED;
7087           }
7088         yield = string_cat(yield, &size, &ptr, s);
7089         continue;
7090         }
7091
7092       case EOP_UTF8_DOMAIN_FROM_ALABEL:
7093         {
7094         uschar * error = NULL;
7095         uschar * s = string_domain_alabel_to_utf8(sub, &error);
7096         if (error)
7097           {
7098           expand_string_message = string_sprintf(
7099             "error converting alabel (%s) to utf8: %s",
7100             string_printing(sub), error);
7101           goto EXPAND_FAILED;
7102           }
7103         yield = string_cat(yield, &size, &ptr, s);
7104         continue;
7105         }
7106
7107       case EOP_UTF8_LOCALPART_TO_ALABEL:
7108         {
7109         uschar * error = NULL;
7110         uschar * s = string_localpart_utf8_to_alabel(sub, &error);
7111         if (error)
7112           {
7113           expand_string_message = string_sprintf(
7114             "error converting utf8 (%s) to alabel: %s",
7115             string_printing(sub), error);
7116           goto EXPAND_FAILED;
7117           }
7118         yield = string_cat(yield, &size, &ptr, s);
7119         DEBUG(D_expand) debug_printf_indent("yield: '%s'\n", yield);
7120         continue;
7121         }
7122
7123       case EOP_UTF8_LOCALPART_FROM_ALABEL:
7124         {
7125         uschar * error = NULL;
7126         uschar * s = string_localpart_alabel_to_utf8(sub, &error);
7127         if (error)
7128           {
7129           expand_string_message = string_sprintf(
7130             "error converting alabel (%s) to utf8: %s",
7131             string_printing(sub), error);
7132           goto EXPAND_FAILED;
7133           }
7134         yield = string_cat(yield, &size, &ptr, s);
7135         continue;
7136         }
7137 #endif  /* EXPERIMENTAL_INTERNATIONAL */
7138
7139       /* escape turns all non-printing characters into escape sequences. */
7140
7141       case EOP_ESCAPE:
7142         {
7143         const uschar * t = string_printing(sub);
7144         yield = string_cat(yield, &size, &ptr, t);
7145         continue;
7146         }
7147
7148       case EOP_ESCAPE8BIT:
7149         {
7150         const uschar * s = sub;
7151         uschar c;
7152
7153         for (s = sub; (c = *s); s++)
7154           yield = c < 127 && c != '\\'
7155             ? string_catn(yield, &size, &ptr, s, 1)
7156             : string_catn(yield, &size, &ptr, string_sprintf("\\%03o", c), 4);
7157         continue;
7158         }
7159
7160       /* Handle numeric expression evaluation */
7161
7162       case EOP_EVAL:
7163       case EOP_EVAL10:
7164         {
7165         uschar *save_sub = sub;
7166         uschar *error = NULL;
7167         int_eximarith_t n = eval_expr(&sub, (c == EOP_EVAL10), &error, FALSE);
7168         if (error != NULL)
7169           {
7170           expand_string_message = string_sprintf("error in expression "
7171             "evaluation: %s (after processing \"%.*s\")", error, sub-save_sub,
7172               save_sub);
7173           goto EXPAND_FAILED;
7174           }
7175         sprintf(CS var_buffer, PR_EXIM_ARITH, n);
7176         yield = string_cat(yield, &size, &ptr, var_buffer);
7177         continue;
7178         }
7179
7180       /* Handle time period formating */
7181
7182       case EOP_TIME_EVAL:
7183         {
7184         int n = readconf_readtime(sub, 0, FALSE);
7185         if (n < 0)
7186           {
7187           expand_string_message = string_sprintf("string \"%s\" is not an "
7188             "Exim time interval in \"%s\" operator", sub, name);
7189           goto EXPAND_FAILED;
7190           }
7191         sprintf(CS var_buffer, "%d", n);
7192         yield = string_cat(yield, &size, &ptr, var_buffer);
7193         continue;
7194         }
7195
7196       case EOP_TIME_INTERVAL:
7197         {
7198         int n;
7199         uschar *t = read_number(&n, sub);
7200         if (*t != 0) /* Not A Number*/
7201           {
7202           expand_string_message = string_sprintf("string \"%s\" is not a "
7203             "positive number in \"%s\" operator", sub, name);
7204           goto EXPAND_FAILED;
7205           }
7206         t = readconf_printtime(n);
7207         yield = string_cat(yield, &size, &ptr, t);
7208         continue;
7209         }
7210
7211       /* Convert string to base64 encoding */
7212
7213       case EOP_STR2B64:
7214       case EOP_BASE64:
7215         {
7216 #ifdef SUPPORT_TLS
7217         uschar * s = vp && *(void **)vp->value
7218           ? tls_cert_der_b64(*(void **)vp->value)
7219           : b64encode(sub, Ustrlen(sub));
7220 #else
7221         uschar * s = b64encode(sub, Ustrlen(sub));
7222 #endif
7223         yield = string_cat(yield, &size, &ptr, s);
7224         continue;
7225         }
7226
7227       case EOP_BASE64D:
7228         {
7229         uschar * s;
7230         int len = b64decode(sub, &s);
7231         if (len < 0)
7232           {
7233           expand_string_message = string_sprintf("string \"%s\" is not "
7234             "well-formed for \"%s\" operator", sub, name);
7235           goto EXPAND_FAILED;
7236           }
7237         yield = string_cat(yield, &size, &ptr, s);
7238         continue;
7239         }
7240
7241       /* strlen returns the length of the string */
7242
7243       case EOP_STRLEN:
7244         {
7245         uschar buff[24];
7246         (void)sprintf(CS buff, "%d", Ustrlen(sub));
7247         yield = string_cat(yield, &size, &ptr, buff);
7248         continue;
7249         }
7250
7251       /* length_n or l_n takes just the first n characters or the whole string,
7252       whichever is the shorter;
7253
7254       substr_m_n, and s_m_n take n characters from offset m; negative m take
7255       from the end; l_n is synonymous with s_0_n. If n is omitted in substr it
7256       takes the rest, either to the right or to the left.
7257
7258       hash_n or h_n makes a hash of length n from the string, yielding n
7259       characters from the set a-z; hash_n_m makes a hash of length n, but
7260       uses m characters from the set a-zA-Z0-9.
7261
7262       nhash_n returns a single number between 0 and n-1 (in text form), while
7263       nhash_n_m returns a div/mod hash as two numbers "a/b". The first lies
7264       between 0 and n-1 and the second between 0 and m-1. */
7265
7266       case EOP_LENGTH:
7267       case EOP_L:
7268       case EOP_SUBSTR:
7269       case EOP_S:
7270       case EOP_HASH:
7271       case EOP_H:
7272       case EOP_NHASH:
7273       case EOP_NH:
7274         {
7275         int sign = 1;
7276         int value1 = 0;
7277         int value2 = -1;
7278         int *pn;
7279         int len;
7280         uschar *ret;
7281
7282         if (arg == NULL)
7283           {
7284           expand_string_message = string_sprintf("missing values after %s",
7285             name);
7286           goto EXPAND_FAILED;
7287           }
7288
7289         /* "length" has only one argument, effectively being synonymous with
7290         substr_0_n. */
7291
7292         if (c == EOP_LENGTH || c == EOP_L)
7293           {
7294           pn = &value2;
7295           value2 = 0;
7296           }
7297
7298         /* The others have one or two arguments; for "substr" the first may be
7299         negative. The second being negative means "not supplied". */
7300
7301         else
7302           {
7303           pn = &value1;
7304           if (name[0] == 's' && *arg == '-') { sign = -1; arg++; }
7305           }
7306
7307         /* Read up to two numbers, separated by underscores */
7308
7309         ret = arg;
7310         while (*arg != 0)
7311           {
7312           if (arg != ret && *arg == '_' && pn == &value1)
7313             {
7314             pn = &value2;
7315             value2 = 0;
7316             if (arg[1] != 0) arg++;
7317             }
7318           else if (!isdigit(*arg))
7319             {
7320             expand_string_message =
7321               string_sprintf("non-digit after underscore in \"%s\"", name);
7322             goto EXPAND_FAILED;
7323             }
7324           else *pn = (*pn)*10 + *arg++ - '0';
7325           }
7326         value1 *= sign;
7327
7328         /* Perform the required operation */
7329
7330         ret =
7331           (c == EOP_HASH || c == EOP_H)?
7332              compute_hash(sub, value1, value2, &len) :
7333           (c == EOP_NHASH || c == EOP_NH)?
7334              compute_nhash(sub, value1, value2, &len) :
7335              extract_substr(sub, value1, value2, &len);
7336
7337         if (ret == NULL) goto EXPAND_FAILED;
7338         yield = string_catn(yield, &size, &ptr, ret, len);
7339         continue;
7340         }
7341
7342       /* Stat a path */
7343
7344       case EOP_STAT:
7345         {
7346         uschar *s;
7347         uschar smode[12];
7348         uschar **modetable[3];
7349         int i;
7350         mode_t mode;
7351         struct stat st;
7352
7353         if ((expand_forbid & RDO_EXISTS) != 0)
7354           {
7355           expand_string_message = US"Use of the stat() expansion is not permitted";
7356           goto EXPAND_FAILED;
7357           }
7358
7359         if (stat(CS sub, &st) < 0)
7360           {
7361           expand_string_message = string_sprintf("stat(%s) failed: %s",
7362             sub, strerror(errno));
7363           goto EXPAND_FAILED;
7364           }
7365         mode = st.st_mode;
7366         switch (mode & S_IFMT)
7367           {
7368           case S_IFIFO: smode[0] = 'p'; break;
7369           case S_IFCHR: smode[0] = 'c'; break;
7370           case S_IFDIR: smode[0] = 'd'; break;
7371           case S_IFBLK: smode[0] = 'b'; break;
7372           case S_IFREG: smode[0] = '-'; break;
7373           default: smode[0] = '?'; break;
7374           }
7375
7376         modetable[0] = ((mode & 01000) == 0)? mtable_normal : mtable_sticky;
7377         modetable[1] = ((mode & 02000) == 0)? mtable_normal : mtable_setid;
7378         modetable[2] = ((mode & 04000) == 0)? mtable_normal : mtable_setid;
7379
7380         for (i = 0; i < 3; i++)
7381           {
7382           memcpy(CS(smode + 7 - i*3), CS(modetable[i][mode & 7]), 3);
7383           mode >>= 3;
7384           }
7385
7386         smode[10] = 0;
7387         s = string_sprintf("mode=%04lo smode=%s inode=%ld device=%ld links=%ld "
7388           "uid=%ld gid=%ld size=" OFF_T_FMT " atime=%ld mtime=%ld ctime=%ld",
7389           (long)(st.st_mode & 077777), smode, (long)st.st_ino,
7390           (long)st.st_dev, (long)st.st_nlink, (long)st.st_uid,
7391           (long)st.st_gid, st.st_size, (long)st.st_atime,
7392           (long)st.st_mtime, (long)st.st_ctime);
7393         yield = string_cat(yield, &size, &ptr, s);
7394         continue;
7395         }
7396
7397       /* vaguely random number less than N */
7398
7399       case EOP_RANDINT:
7400         {
7401         int_eximarith_t max;
7402         uschar *s;
7403
7404         max = expanded_string_integer(sub, TRUE);
7405         if (expand_string_message != NULL)
7406           goto EXPAND_FAILED;
7407         s = string_sprintf("%d", vaguely_random_number((int)max));
7408         yield = string_cat(yield, &size, &ptr, s);
7409         continue;
7410         }
7411
7412       /* Reverse IP, including IPv6 to dotted-nibble */
7413
7414       case EOP_REVERSE_IP:
7415         {
7416         int family, maskptr;
7417         uschar reversed[128];
7418
7419         family = string_is_ip_address(sub, &maskptr);
7420         if (family == 0)
7421           {
7422           expand_string_message = string_sprintf(
7423               "reverse_ip() not given an IP address [%s]", sub);
7424           goto EXPAND_FAILED;
7425           }
7426         invert_address(reversed, sub);
7427         yield = string_cat(yield, &size, &ptr, reversed);
7428         continue;
7429         }
7430
7431       /* Unknown operator */
7432
7433       default:
7434       expand_string_message =
7435         string_sprintf("unknown expansion operator \"%s\"", name);
7436       goto EXPAND_FAILED;
7437       }
7438     }
7439
7440   /* Handle a plain name. If this is the first thing in the expansion, release
7441   the pre-allocated buffer. If the result data is known to be in a new buffer,
7442   newsize will be set to the size of that buffer, and we can just point at that
7443   store instead of copying. Many expansion strings contain just one reference,
7444   so this is a useful optimization, especially for humungous headers
7445   ($message_headers). */
7446                                                 /*{*/
7447   if (*s++ == '}')
7448     {
7449     int len;
7450     int newsize = 0;
7451     if (ptr == 0)
7452       {
7453       if (resetok) store_reset(yield);
7454       yield = NULL;
7455       size = 0;
7456       }
7457     if (!(value = find_variable(name, FALSE, skipping, &newsize)))
7458       {
7459       expand_string_message =
7460         string_sprintf("unknown variable in \"${%s}\"", name);
7461       check_variable_error_message(name);
7462       goto EXPAND_FAILED;
7463       }
7464     len = Ustrlen(value);
7465     if (!yield && newsize)
7466       {
7467       yield = value;
7468       size = newsize;
7469       ptr = len;
7470       }
7471     else
7472       yield = string_catn(yield, &size, &ptr, value, len);
7473     continue;
7474     }
7475
7476   /* Else there's something wrong */
7477
7478   expand_string_message =
7479     string_sprintf("\"${%s\" is not a known operator (or a } is missing "
7480     "in a variable reference)", name);
7481   goto EXPAND_FAILED;
7482   }
7483
7484 /* If we hit the end of the string when ket_ends is set, there is a missing
7485 terminating brace. */
7486
7487 if (ket_ends && *s == 0)
7488   {
7489   expand_string_message = malformed_header?
7490     US"missing } at end of string - could be header name not terminated by colon"
7491     :
7492     US"missing } at end of string";
7493   goto EXPAND_FAILED;
7494   }
7495
7496 /* Expansion succeeded; yield may still be NULL here if nothing was actually
7497 added to the string. If so, set up an empty string. Add a terminating zero. If
7498 left != NULL, return a pointer to the terminator. */
7499
7500 if (yield == NULL) yield = store_get(1);
7501 yield[ptr] = 0;
7502 if (left != NULL) *left = s;
7503
7504 /* Any stacking store that was used above the final string is no longer needed.
7505 In many cases the final string will be the first one that was got and so there
7506 will be optimal store usage. */
7507
7508 if (resetok) store_reset(yield + ptr + 1);
7509 else if (resetok_p) *resetok_p = FALSE;
7510
7511 DEBUG(D_expand)
7512   {
7513   debug_printf_indent(UTF8_VERT_RIGHT UTF8_HORIZ UTF8_HORIZ
7514     "expanding: %.*s\n",
7515     (int)(s - string), string);
7516   debug_printf_indent("%s"
7517     UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ
7518     "result: %s\n",
7519     skipping ? UTF8_VERT_RIGHT : UTF8_UP_RIGHT,
7520     yield);
7521   if (skipping)
7522     debug_printf_indent(UTF8_UP_RIGHT UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ
7523       "skipping: result is not used\n");
7524   }
7525 expand_level--;
7526 return yield;
7527
7528 /* This is the failure exit: easiest to program with a goto. We still need
7529 to update the pointer to the terminator, for cases of nested calls with "fail".
7530 */
7531
7532 EXPAND_FAILED_CURLY:
7533 if (malformed_header)
7534   expand_string_message =
7535     US"missing or misplaced { or } - could be header name not terminated by colon";
7536
7537 else if (!expand_string_message || !*expand_string_message)
7538   expand_string_message = US"missing or misplaced { or }";
7539
7540 /* At one point, Exim reset the store to yield (if yield was not NULL), but
7541 that is a bad idea, because expand_string_message is in dynamic store. */
7542
7543 EXPAND_FAILED:
7544 if (left != NULL) *left = s;
7545 DEBUG(D_expand)
7546   {
7547   debug_printf_indent(UTF8_VERT_RIGHT "failed to expand: %s\n",
7548     string);
7549   debug_printf_indent("%s" UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ
7550     "error message: %s\n",
7551     expand_string_forcedfail ? UTF8_VERT_RIGHT : UTF8_UP_RIGHT,
7552     expand_string_message);
7553   if (expand_string_forcedfail)
7554     debug_printf_indent(UTF8_UP_RIGHT "failure was forced\n");
7555   }
7556 if (resetok_p) *resetok_p = resetok;
7557 expand_level--;
7558 return NULL;
7559 }
7560
7561
7562 /* This is the external function call. Do a quick check for any expansion
7563 metacharacters, and if there are none, just return the input string.
7564
7565 Argument: the string to be expanded
7566 Returns:  the expanded string, or NULL if expansion failed; if failure was
7567           due to a lookup deferring, search_find_defer will be TRUE
7568 */
7569
7570 uschar *
7571 expand_string(uschar *string)
7572 {
7573 search_find_defer = FALSE;
7574 malformed_header = FALSE;
7575 return (Ustrpbrk(string, "$\\") == NULL)? string :
7576   expand_string_internal(string, FALSE, NULL, FALSE, TRUE, NULL);
7577 }
7578
7579
7580
7581 const uschar *
7582 expand_cstring(const uschar *string)
7583 {
7584 search_find_defer = FALSE;
7585 malformed_header = FALSE;
7586 return (Ustrpbrk(string, "$\\") == NULL)? string :
7587   expand_string_internal(string, FALSE, NULL, FALSE, TRUE, NULL);
7588 }
7589
7590
7591
7592 /*************************************************
7593 *              Expand and copy                   *
7594 *************************************************/
7595
7596 /* Now and again we want to expand a string and be sure that the result is in a
7597 new bit of store. This function does that.
7598 Since we know it has been copied, the de-const cast is safe.
7599
7600 Argument: the string to be expanded
7601 Returns:  the expanded string, always in a new bit of store, or NULL
7602 */
7603
7604 uschar *
7605 expand_string_copy(const uschar *string)
7606 {
7607 const uschar *yield = expand_cstring(string);
7608 if (yield == string) yield = string_copy(string);
7609 return US yield;
7610 }
7611
7612
7613
7614 /*************************************************
7615 *        Expand and interpret as an integer      *
7616 *************************************************/
7617
7618 /* Expand a string, and convert the result into an integer.
7619
7620 Arguments:
7621   string  the string to be expanded
7622   isplus  TRUE if a non-negative number is expected
7623
7624 Returns:  the integer value, or
7625           -1 for an expansion error               ) in both cases, message in
7626           -2 for an integer interpretation error  ) expand_string_message
7627           expand_string_message is set NULL for an OK integer
7628 */
7629
7630 int_eximarith_t
7631 expand_string_integer(uschar *string, BOOL isplus)
7632 {
7633 return expanded_string_integer(expand_string(string), isplus);
7634 }
7635
7636
7637 /*************************************************
7638  *         Interpret string as an integer        *
7639  *************************************************/
7640
7641 /* Convert a string (that has already been expanded) into an integer.
7642
7643 This function is used inside the expansion code.
7644
7645 Arguments:
7646   s       the string to be expanded
7647   isplus  TRUE if a non-negative number is expected
7648
7649 Returns:  the integer value, or
7650           -1 if string is NULL (which implies an expansion error)
7651           -2 for an integer interpretation error
7652           expand_string_message is set NULL for an OK integer
7653 */
7654
7655 static int_eximarith_t
7656 expanded_string_integer(const uschar *s, BOOL isplus)
7657 {
7658 int_eximarith_t value;
7659 uschar *msg = US"invalid integer \"%s\"";
7660 uschar *endptr;
7661
7662 /* If expansion failed, expand_string_message will be set. */
7663
7664 if (s == NULL) return -1;
7665
7666 /* On an overflow, strtol() returns LONG_MAX or LONG_MIN, and sets errno
7667 to ERANGE. When there isn't an overflow, errno is not changed, at least on some
7668 systems, so we set it zero ourselves. */
7669
7670 errno = 0;
7671 expand_string_message = NULL;               /* Indicates no error */
7672
7673 /* Before Exim 4.64, strings consisting entirely of whitespace compared
7674 equal to 0.  Unfortunately, people actually relied upon that, so preserve
7675 the behaviour explicitly.  Stripping leading whitespace is a harmless
7676 noop change since strtol skips it anyway (provided that there is a number
7677 to find at all). */
7678 if (isspace(*s))
7679   {
7680   while (isspace(*s)) ++s;
7681   if (*s == '\0')
7682     {
7683       DEBUG(D_expand)
7684        debug_printf_indent("treating blank string as number 0\n");
7685       return 0;
7686     }
7687   }
7688
7689 value = strtoll(CS s, CSS &endptr, 10);
7690
7691 if (endptr == s)
7692   {
7693   msg = US"integer expected but \"%s\" found";
7694   }
7695 else if (value < 0 && isplus)
7696   {
7697   msg = US"non-negative integer expected but \"%s\" found";
7698   }
7699 else
7700   {
7701   switch (tolower(*endptr))
7702     {
7703     default:
7704       break;
7705     case 'k':
7706       if (value > EXIM_ARITH_MAX/1024 || value < EXIM_ARITH_MIN/1024) errno = ERANGE;
7707       else value *= 1024;
7708       endptr++;
7709       break;
7710     case 'm':
7711       if (value > EXIM_ARITH_MAX/(1024*1024) || value < EXIM_ARITH_MIN/(1024*1024)) errno = ERANGE;
7712       else value *= 1024*1024;
7713       endptr++;
7714       break;
7715     case 'g':
7716       if (value > EXIM_ARITH_MAX/(1024*1024*1024) || value < EXIM_ARITH_MIN/(1024*1024*1024)) errno = ERANGE;
7717       else value *= 1024*1024*1024;
7718       endptr++;
7719       break;
7720     }
7721   if (errno == ERANGE)
7722     msg = US"absolute value of integer \"%s\" is too large (overflow)";
7723   else
7724     {
7725     while (isspace(*endptr)) endptr++;
7726     if (*endptr == 0) return value;
7727     }
7728   }
7729
7730 expand_string_message = string_sprintf(CS msg, s);
7731 return -2;
7732 }
7733
7734
7735 /* These values are usually fixed boolean values, but they are permitted to be
7736 expanded strings.
7737
7738 Arguments:
7739   addr       address being routed
7740   mtype      the module type
7741   mname      the module name
7742   dbg_opt    debug selectors
7743   oname      the option name
7744   bvalue     the router's boolean value
7745   svalue     the router's string value
7746   rvalue     where to put the returned value
7747
7748 Returns:     OK     value placed in rvalue
7749              DEFER  expansion failed
7750 */
7751
7752 int
7753 exp_bool(address_item *addr,
7754   uschar *mtype, uschar *mname, unsigned dbg_opt,
7755   uschar *oname, BOOL bvalue,
7756   uschar *svalue, BOOL *rvalue)
7757 {
7758 uschar *expanded;
7759 if (svalue == NULL) { *rvalue = bvalue; return OK; }
7760
7761 expanded = expand_string(svalue);
7762 if (expanded == NULL)
7763   {
7764   if (expand_string_forcedfail)
7765     {
7766     DEBUG(dbg_opt) debug_printf("expansion of \"%s\" forced failure\n", oname);
7767     *rvalue = bvalue;
7768     return OK;
7769     }
7770   addr->message = string_sprintf("failed to expand \"%s\" in %s %s: %s",
7771       oname, mname, mtype, expand_string_message);
7772   DEBUG(dbg_opt) debug_printf("%s\n", addr->message);
7773   return DEFER;
7774   }
7775
7776 DEBUG(dbg_opt) debug_printf("expansion of \"%s\" yields \"%s\"\n", oname,
7777   expanded);
7778
7779 if (strcmpic(expanded, US"true") == 0 || strcmpic(expanded, US"yes") == 0)
7780   *rvalue = TRUE;
7781 else if (strcmpic(expanded, US"false") == 0 || strcmpic(expanded, US"no") == 0)
7782   *rvalue = FALSE;
7783 else
7784   {
7785   addr->message = string_sprintf("\"%s\" is not a valid value for the "
7786     "\"%s\" option in the %s %s", expanded, oname, mname, mtype);
7787   return DEFER;
7788   }
7789
7790 return OK;
7791 }
7792
7793
7794
7795 /* Avoid potentially exposing a password in a string about to be logged */
7796
7797 uschar *
7798 expand_hide_passwords(uschar * s)
7799 {
7800 return (  (  Ustrstr(s, "failed to expand") != NULL
7801           || Ustrstr(s, "expansion of ")    != NULL
7802           )
7803        && (  Ustrstr(s, "mysql")   != NULL
7804           || Ustrstr(s, "pgsql")   != NULL
7805           || Ustrstr(s, "redis")   != NULL
7806           || Ustrstr(s, "sqlite")  != NULL
7807           || Ustrstr(s, "ldap:")   != NULL
7808           || Ustrstr(s, "ldaps:")  != NULL
7809           || Ustrstr(s, "ldapi:")  != NULL
7810           || Ustrstr(s, "ldapdn:") != NULL
7811           || Ustrstr(s, "ldapm:")  != NULL
7812        )  )
7813   ? US"Temporary internal error" : s;
7814 }
7815
7816
7817
7818 /*************************************************
7819 * Error-checking for testsuite                   *
7820 *************************************************/
7821 typedef struct {
7822   const char *  filename;
7823   int           linenumber;
7824   uschar *      region_start;
7825   uschar *      region_end;
7826   const uschar *var_name;
7827   const uschar *var_data;
7828 } err_ctx;
7829
7830 static void
7831 assert_variable_notin(uschar * var_name, uschar * var_data, void * ctx)
7832 {
7833 err_ctx * e = ctx;
7834 if (var_data >= e->region_start  &&  var_data < e->region_end)
7835   {
7836   e->var_name = CUS var_name;
7837   e->var_data = CUS var_data;
7838   }
7839 }
7840
7841 void
7842 assert_no_variables(void * ptr, int len, const char * filename, int linenumber)
7843 {
7844 err_ctx e = {filename, linenumber, ptr, US ptr + len, NULL };
7845 int i;
7846 var_entry * v;
7847
7848 /* check acl_ variables */
7849 tree_walk(acl_var_c, assert_variable_notin, &e);
7850 tree_walk(acl_var_m, assert_variable_notin, &e);
7851
7852 /* check auth<n> variables */
7853 for (i = 0; i < AUTH_VARS; i++) if (auth_vars[i])
7854   assert_variable_notin(US"auth<n>", auth_vars[i], &e);
7855
7856 /* check regex<n> variables */
7857 for (i = 0; i < REGEX_VARS; i++) if (regex_vars[i])
7858   assert_variable_notin(US"regex<n>", regex_vars[i], &e);
7859
7860 /* check known-name variables */
7861 for (v = var_table; v < var_table + var_table_size; v++)
7862   if (v->type == vtype_stringptr)
7863     assert_variable_notin(US v->name, *(USS v->value), &e);
7864
7865 if (e.var_name)
7866   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
7867     "live variable '%s' destroyed by reset_store at %s:%d\n- value '%.64s'",
7868     e.var_name, e.filename, e.linenumber, e.var_data);
7869 }
7870
7871
7872
7873 /*************************************************
7874 **************************************************
7875 *             Stand-alone test program           *
7876 **************************************************
7877 *************************************************/
7878
7879 #ifdef STAND_ALONE
7880
7881
7882 BOOL
7883 regex_match_and_setup(const pcre *re, uschar *subject, int options, int setup)
7884 {
7885 int ovector[3*(EXPAND_MAXN+1)];
7886 int n = pcre_exec(re, NULL, subject, Ustrlen(subject), 0, PCRE_EOPT|options,
7887   ovector, nelem(ovector));
7888 BOOL yield = n >= 0;
7889 if (n == 0) n = EXPAND_MAXN + 1;
7890 if (yield)
7891   {
7892   int nn;
7893   expand_nmax = (setup < 0)? 0 : setup + 1;
7894   for (nn = (setup < 0)? 0 : 2; nn < n*2; nn += 2)
7895     {
7896     expand_nstring[expand_nmax] = subject + ovector[nn];
7897     expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
7898     }
7899   expand_nmax--;
7900   }
7901 return yield;
7902 }
7903
7904
7905 int main(int argc, uschar **argv)
7906 {
7907 int i;
7908 uschar buffer[1024];
7909
7910 debug_selector = D_v;
7911 debug_file = stderr;
7912 debug_fd = fileno(debug_file);
7913 big_buffer = malloc(big_buffer_size);
7914
7915 for (i = 1; i < argc; i++)
7916   {
7917   if (argv[i][0] == '+')
7918     {
7919     debug_trace_memory = 2;
7920     argv[i]++;
7921     }
7922   if (isdigit(argv[i][0]))
7923     debug_selector = Ustrtol(argv[i], NULL, 0);
7924   else
7925     if (Ustrspn(argv[i], "abcdefghijklmnopqrtsuvwxyz0123456789-.:/") ==
7926         Ustrlen(argv[i]))
7927       {
7928 #ifdef LOOKUP_LDAP
7929       eldap_default_servers = argv[i];
7930 #endif
7931 #ifdef LOOKUP_MYSQL
7932       mysql_servers = argv[i];
7933 #endif
7934 #ifdef LOOKUP_PGSQL
7935       pgsql_servers = argv[i];
7936 #endif
7937 #ifdef LOOKUP_REDIS
7938       redis_servers = argv[i];
7939 #endif
7940       }
7941 #ifdef EXIM_PERL
7942   else opt_perl_startup = argv[i];
7943 #endif
7944   }
7945
7946 printf("Testing string expansion: debug_level = %d\n\n", debug_level);
7947
7948 expand_nstring[1] = US"string 1....";
7949 expand_nlength[1] = 8;
7950 expand_nmax = 1;
7951
7952 #ifdef EXIM_PERL
7953 if (opt_perl_startup != NULL)
7954   {
7955   uschar *errstr;
7956   printf("Starting Perl interpreter\n");
7957   errstr = init_perl(opt_perl_startup);
7958   if (errstr != NULL)
7959     {
7960     printf("** error in perl_startup code: %s\n", errstr);
7961     return EXIT_FAILURE;
7962     }
7963   }
7964 #endif /* EXIM_PERL */
7965
7966 while (fgets(buffer, sizeof(buffer), stdin) != NULL)
7967   {
7968   void *reset_point = store_get(0);
7969   uschar *yield = expand_string(buffer);
7970   if (yield != NULL)
7971     {
7972     printf("%s\n", yield);
7973     store_reset(reset_point);
7974     }
7975   else
7976     {
7977     if (search_find_defer) printf("search_find deferred\n");
7978     printf("Failed: %s\n", expand_string_message);
7979     if (expand_string_forcedfail) printf("Forced failure\n");
7980     printf("\n");
7981     }
7982   }
7983
7984 search_tidyup();
7985
7986 return 0;
7987 }
7988
7989 #endif
7990
7991 /* vi: aw ai sw=2
7992 */
7993 /* End of expand.c */