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