src/src/expand.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2017 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8
   9 /* Functions for handling string expansion. */
  10
  11
  12 #include "exim.h"
  13
  14 /* Recursively called function */
  15
  16 static uschar *expand_string_internal(const uschar *, BOOL, const uschar **, BOOL, BOOL, BOOL *);
  17 static int_eximarith_t expanded_string_integer(const uschar *, BOOL);
  18
  19 #ifdef STAND_ALONE
  20 #ifndef SUPPORT_CRYPTEQ
  21 #define SUPPORT_CRYPTEQ
  22 #endif
  23 #endif
  24
  25 #ifdef LOOKUP_LDAP
  26 #include "lookups/ldap.h"
  27 #endif
  28
  29 #ifdef SUPPORT_CRYPTEQ
  30 #ifdef CRYPT_H
  31 #include <crypt.h>
  32 #endif
  33 #ifndef HAVE_CRYPT16
  34 extern char* crypt16(char*, char*);
  35 #endif
  36 #endif
  37
  38 /* The handling of crypt16() is a mess. I will record below the analysis of the
  39 mess that was sent to me. We decided, however, to make changing this very low
  40 priority, because in practice people are moving away from the crypt()
  41 algorithms nowadays, so it doesn't seem worth it.
  42
  43 <quote>
  44 There is an algorithm named "crypt16" in Ultrix and Tru64.  It crypts
  45 the first 8 characters of the password using a 20-round version of crypt
  46 (standard crypt does 25 rounds).  It then crypts the next 8 characters,
  47 or an empty block if the password is less than 9 characters, using a
  48 20-round version of crypt and the same salt as was used for the first
  49 block.  Characters after the first 16 are ignored.  It always generates
  50 a 16-byte hash, which is expressed together with the salt as a string
  51 of 24 base 64 digits.  Here are some links to peruse:
  52
  53         http://cvs.pld.org.pl/pam/pamcrypt/crypt16.c?rev=1.2
  54         http://seclists.org/bugtraq/1999/Mar/0076.html
  55
  56 There's a different algorithm named "bigcrypt" in HP-UX, Digital Unix,
  57 and OSF/1.  This is the same as the standard crypt if given a password
  58 of 8 characters or less.  If given more, it first does the same as crypt
  59 using the first 8 characters, then crypts the next 8 (the 9th to 16th)
  60 using as salt the first two base 64 digits from the first hash block.
  61 If the password is more than 16 characters then it crypts the 17th to 24th
  62 characters using as salt the first two base 64 digits from the second hash
  63 block.  And so on: I've seen references to it cutting off the password at
  64 40 characters (5 blocks), 80 (10 blocks), or 128 (16 blocks).  Some links:
  65
  66         http://cvs.pld.org.pl/pam/pamcrypt/bigcrypt.c?rev=1.2
  67         http://seclists.org/bugtraq/1999/Mar/0109.html
  68         http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R2D-
  69              TET1_html/sec.c222.html#no_id_208
  70
  71 Exim has something it calls "crypt16".  It will either use a native
  72 crypt16 or its own implementation.  A native crypt16 will presumably
  73 be the one that I called "crypt16" above.  The internal "crypt16"
  74 function, however, is a two-block-maximum implementation of what I called
  75 "bigcrypt".  The documentation matches the internal code.
  76
  77 I suspect that whoever did the "crypt16" stuff for Exim didn't realise
  78 that crypt16 and bigcrypt were different things.
  79
  80 Exim uses the LDAP-style scheme identifier "{crypt16}" to refer
  81 to whatever it is using under that name.  This unfortunately sets a
  82 precedent for using "{crypt16}" to identify two incompatible algorithms
  83 whose output can't be distinguished.  With "{crypt16}" thus rendered
  84 ambiguous, I suggest you deprecate it and invent two new identifiers
  85 for the two algorithms.
  86
  87 Both crypt16 and bigcrypt are very poor algorithms, btw.  Hashing parts
  88 of the password separately means they can be cracked separately, so
  89 the double-length hash only doubles the cracking effort instead of
  90 squaring it.  I recommend salted SHA-1 ({SSHA}), or the Blowfish-based
  91 bcrypt ({CRYPT}$2a$).
  92 </quote>
  93 */
  94
  95
  96
  97 /*************************************************
  98 *            Local statics and tables            *
  99 *************************************************/
 100
 101 /* Table of item names, and corresponding switch numbers. The names must be in
 102 alphabetical order. */
 103
 104 static uschar *item_table[] = {
 105   US"acl",
 106   US"certextract",
 107   US"dlfunc",
 108   US"env",
 109   US"extract",
 110   US"filter",
 111   US"hash",
 112   US"hmac",
 113   US"if",
 114 #ifdef SUPPORT_I18N
 115   US"imapfolder",
 116 #endif
 117   US"length",
 118   US"listextract",
 119   US"lookup",
 120   US"map",
 121   US"nhash",
 122   US"perl",
 123   US"prvs",
 124   US"prvscheck",
 125   US"readfile",
 126   US"readsocket",
 127   US"reduce",
 128   US"run",
 129   US"sg",
 130   US"sort",
 131   US"substr",
 132   US"tr" };
 133
 134 enum {
 135   EITEM_ACL,
 136   EITEM_CERTEXTRACT,
 137   EITEM_DLFUNC,
 138   EITEM_ENV,
 139   EITEM_EXTRACT,
 140   EITEM_FILTER,
 141   EITEM_HASH,
 142   EITEM_HMAC,
 143   EITEM_IF,
 144 #ifdef SUPPORT_I18N
 145   EITEM_IMAPFOLDER,
 146 #endif
 147   EITEM_LENGTH,
 148   EITEM_LISTEXTRACT,
 149   EITEM_LOOKUP,
 150   EITEM_MAP,
 151   EITEM_NHASH,
 152   EITEM_PERL,
 153   EITEM_PRVS,
 154   EITEM_PRVSCHECK,
 155   EITEM_READFILE,
 156   EITEM_READSOCK,
 157   EITEM_REDUCE,
 158   EITEM_RUN,
 159   EITEM_SG,
 160   EITEM_SORT,
 161   EITEM_SUBSTR,
 162   EITEM_TR };
 163
 164 /* Tables of operator names, and corresponding switch numbers. The names must be
 165 in alphabetical order. There are two tables, because underscore is used in some
 166 cases to introduce arguments, whereas for other it is part of the name. This is
 167 an historical mis-design. */
 168
 169 static uschar *op_table_underscore[] = {
 170   US"from_utf8",
 171   US"local_part",
 172   US"quote_local_part",
 173   US"reverse_ip",
 174   US"time_eval",
 175   US"time_interval"
 176 #ifdef SUPPORT_I18N
 177  ,US"utf8_domain_from_alabel",
 178   US"utf8_domain_to_alabel",
 179   US"utf8_localpart_from_alabel",
 180   US"utf8_localpart_to_alabel"
 181 #endif
 182   };
 183
 184 enum {
 185   EOP_FROM_UTF8,
 186   EOP_LOCAL_PART,
 187   EOP_QUOTE_LOCAL_PART,
 188   EOP_REVERSE_IP,
 189   EOP_TIME_EVAL,
 190   EOP_TIME_INTERVAL
 191 #ifdef SUPPORT_I18N
 192  ,EOP_UTF8_DOMAIN_FROM_ALABEL,
 193   EOP_UTF8_DOMAIN_TO_ALABEL,
 194   EOP_UTF8_LOCALPART_FROM_ALABEL,
 195   EOP_UTF8_LOCALPART_TO_ALABEL
 196 #endif
 197   };
 198
 199 static uschar *op_table_main[] = {
 200   US"address",
 201   US"addresses",
 202   US"base32",
 203   US"base32d",
 204   US"base62",
 205   US"base62d",
 206   US"base64",
 207   US"base64d",
 208   US"domain",
 209   US"escape",
 210   US"escape8bit",
 211   US"eval",
 212   US"eval10",
 213   US"expand",
 214   US"h",
 215   US"hash",
 216   US"hex2b64",
 217   US"hexquote",
 218   US"ipv6denorm",
 219   US"ipv6norm",
 220   US"l",
 221   US"lc",
 222   US"length",
 223   US"listcount",
 224   US"listnamed",
 225   US"mask",
 226   US"md5",
 227   US"nh",
 228   US"nhash",
 229   US"quote",
 230   US"randint",
 231   US"rfc2047",
 232   US"rfc2047d",
 233   US"rxquote",
 234   US"s",
 235   US"sha1",
 236   US"sha256",
 237   US"sha3",
 238   US"stat",
 239   US"str2b64",
 240   US"strlen",
 241   US"substr",
 242   US"uc",
 243   US"utf8clean" };
 244
 245 enum {
 246   EOP_ADDRESS =  nelem(op_table_underscore),
 247   EOP_ADDRESSES,
 248   EOP_BASE32,
 249   EOP_BASE32D,
 250   EOP_BASE62,
 251   EOP_BASE62D,
 252   EOP_BASE64,
 253   EOP_BASE64D,
 254   EOP_DOMAIN,
 255   EOP_ESCAPE,
 256   EOP_ESCAPE8BIT,
 257   EOP_EVAL,
 258   EOP_EVAL10,
 259   EOP_EXPAND,
 260   EOP_H,
 261   EOP_HASH,
 262   EOP_HEX2B64,
 263   EOP_HEXQUOTE,
 264   EOP_IPV6DENORM,
 265   EOP_IPV6NORM,
 266   EOP_L,
 267   EOP_LC,
 268   EOP_LENGTH,
 269   EOP_LISTCOUNT,
 270   EOP_LISTNAMED,
 271   EOP_MASK,
 272   EOP_MD5,
 273   EOP_NH,
 274   EOP_NHASH,
 275   EOP_QUOTE,
 276   EOP_RANDINT,
 277   EOP_RFC2047,
 278   EOP_RFC2047D,
 279   EOP_RXQUOTE,
 280   EOP_S,
 281   EOP_SHA1,
 282   EOP_SHA256,
 283   EOP_SHA3,
 284   EOP_STAT,
 285   EOP_STR2B64,
 286   EOP_STRLEN,
 287   EOP_SUBSTR,
 288   EOP_UC,
 289   EOP_UTF8CLEAN };
 290
 291
 292 /* Table of condition names, and corresponding switch numbers. The names must
 293 be in alphabetical order. */
 294
 295 static uschar *cond_table[] = {
 296   US"<",
 297   US"<=",
 298   US"=",
 299   US"==",     /* Backward compatibility */
 300   US">",
 301   US">=",
 302   US"acl",
 303   US"and",
 304   US"bool",
 305   US"bool_lax",
 306   US"crypteq",
 307   US"def",
 308   US"eq",
 309   US"eqi",
 310   US"exists",
 311   US"first_delivery",
 312   US"forall",
 313   US"forany",
 314   US"ge",
 315   US"gei",
 316   US"gt",
 317   US"gti",
 318   US"inlist",
 319   US"inlisti",
 320   US"isip",
 321   US"isip4",
 322   US"isip6",
 323   US"ldapauth",
 324   US"le",
 325   US"lei",
 326   US"lt",
 327   US"lti",
 328   US"match",
 329   US"match_address",
 330   US"match_domain",
 331   US"match_ip",
 332   US"match_local_part",
 333   US"or",
 334   US"pam",
 335   US"pwcheck",
 336   US"queue_running",
 337   US"radius",
 338   US"saslauthd"
 339 };
 340
 341 enum {
 342   ECOND_NUM_L,
 343   ECOND_NUM_LE,
 344   ECOND_NUM_E,
 345   ECOND_NUM_EE,
 346   ECOND_NUM_G,
 347   ECOND_NUM_GE,
 348   ECOND_ACL,
 349   ECOND_AND,
 350   ECOND_BOOL,
 351   ECOND_BOOL_LAX,
 352   ECOND_CRYPTEQ,
 353   ECOND_DEF,
 354   ECOND_STR_EQ,
 355   ECOND_STR_EQI,
 356   ECOND_EXISTS,
 357   ECOND_FIRST_DELIVERY,
 358   ECOND_FORALL,
 359   ECOND_FORANY,
 360   ECOND_STR_GE,
 361   ECOND_STR_GEI,
 362   ECOND_STR_GT,
 363   ECOND_STR_GTI,
 364   ECOND_INLIST,
 365   ECOND_INLISTI,
 366   ECOND_ISIP,
 367   ECOND_ISIP4,
 368   ECOND_ISIP6,
 369   ECOND_LDAPAUTH,
 370   ECOND_STR_LE,
 371   ECOND_STR_LEI,
 372   ECOND_STR_LT,
 373   ECOND_STR_LTI,
 374   ECOND_MATCH,
 375   ECOND_MATCH_ADDRESS,
 376   ECOND_MATCH_DOMAIN,
 377   ECOND_MATCH_IP,
 378   ECOND_MATCH_LOCAL_PART,
 379   ECOND_OR,
 380   ECOND_PAM,
 381   ECOND_PWCHECK,
 382   ECOND_QUEUE_RUNNING,
 383   ECOND_RADIUS,
 384   ECOND_SASLAUTHD
 385 };
 386
 387
 388 /* Types of table entry */
 389
 390 enum vtypes {
 391   vtype_int,            /* value is address of int */
 392   vtype_filter_int,     /* ditto, but recognized only when filtering */
 393   vtype_ino,            /* value is address of ino_t (not always an int) */
 394   vtype_uid,            /* value is address of uid_t (not always an int) */
 395   vtype_gid,            /* value is address of gid_t (not always an int) */
 396   vtype_bool,           /* value is address of bool */
 397   vtype_stringptr,      /* value is address of pointer to string */
 398   vtype_msgbody,        /* as stringptr, but read when first required */
 399   vtype_msgbody_end,    /* ditto, the end of the message */
 400   vtype_msgheaders,     /* the message's headers, processed */
 401   vtype_msgheaders_raw, /* the message's headers, unprocessed */
 402   vtype_localpart,      /* extract local part from string */
 403   vtype_domain,         /* extract domain from string */
 404   vtype_string_func,    /* value is string returned by given function */
 405   vtype_todbsdin,       /* value not used; generate BSD inbox tod */
 406   vtype_tode,           /* value not used; generate tod in epoch format */
 407   vtype_todel,          /* value not used; generate tod in epoch/usec format */
 408   vtype_todf,           /* value not used; generate full tod */
 409   vtype_todl,           /* value not used; generate log tod */
 410   vtype_todlf,          /* value not used; generate log file datestamp tod */
 411   vtype_todzone,        /* value not used; generate time zone only */
 412   vtype_todzulu,        /* value not used; generate zulu tod */
 413   vtype_reply,          /* value not used; get reply from headers */
 414   vtype_pid,            /* value not used; result is pid */
 415   vtype_host_lookup,    /* value not used; get host name */
 416   vtype_load_avg,       /* value not used; result is int from os_getloadavg */
 417   vtype_pspace,         /* partition space; value is T/F for spool/log */
 418   vtype_pinodes,        /* partition inodes; value is T/F for spool/log */
 419   vtype_cert            /* SSL certificate */
 420   #ifndef DISABLE_DKIM
 421   ,vtype_dkim           /* Lookup of value in DKIM signature */
 422   #endif
 423 };
 424
 425 /* Type for main variable table */
 426
 427 typedef struct {
 428   const char *name;
 429   enum vtypes type;
 430   void       *value;
 431 } var_entry;
 432
 433 /* Type for entries pointing to address/length pairs. Not currently
 434 in use. */
 435
 436 typedef struct {
 437   uschar **address;
 438   int  *length;
 439 } alblock;
 440
 441 static uschar * fn_recipients(void);
 442
 443 /* This table must be kept in alphabetical order. */
 444
 445 static var_entry var_table[] = {
 446   /* WARNING: Do not invent variables whose names start acl_c or acl_m because
 447      they will be confused with user-creatable ACL variables. */
 448   { "acl_arg1",            vtype_stringptr,   &acl_arg[0] },
 449   { "acl_arg2",            vtype_stringptr,   &acl_arg[1] },
 450   { "acl_arg3",            vtype_stringptr,   &acl_arg[2] },
 451   { "acl_arg4",            vtype_stringptr,   &acl_arg[3] },
 452   { "acl_arg5",            vtype_stringptr,   &acl_arg[4] },
 453   { "acl_arg6",            vtype_stringptr,   &acl_arg[5] },
 454   { "acl_arg7",            vtype_stringptr,   &acl_arg[6] },
 455   { "acl_arg8",            vtype_stringptr,   &acl_arg[7] },
 456   { "acl_arg9",            vtype_stringptr,   &acl_arg[8] },
 457   { "acl_narg",            vtype_int,         &acl_narg },
 458   { "acl_verify_message",  vtype_stringptr,   &acl_verify_message },
 459   { "address_data",        vtype_stringptr,   &deliver_address_data },
 460   { "address_file",        vtype_stringptr,   &address_file },
 461   { "address_pipe",        vtype_stringptr,   &address_pipe },
 462   { "authenticated_fail_id",vtype_stringptr,  &authenticated_fail_id },
 463   { "authenticated_id",    vtype_stringptr,   &authenticated_id },
 464   { "authenticated_sender",vtype_stringptr,   &authenticated_sender },
 465   { "authentication_failed",vtype_int,        &authentication_failed },
 466 #ifdef WITH_CONTENT_SCAN
 467   { "av_failed",           vtype_int,         &av_failed },
 468 #endif
 469 #ifdef EXPERIMENTAL_BRIGHTMAIL
 470   { "bmi_alt_location",    vtype_stringptr,   &bmi_alt_location },
 471   { "bmi_base64_tracker_verdict", vtype_stringptr, &bmi_base64_tracker_verdict },
 472   { "bmi_base64_verdict",  vtype_stringptr,   &bmi_base64_verdict },
 473   { "bmi_deliver",         vtype_int,         &bmi_deliver },
 474 #endif
 475   { "body_linecount",      vtype_int,         &body_linecount },
 476   { "body_zerocount",      vtype_int,         &body_zerocount },
 477   { "bounce_recipient",    vtype_stringptr,   &bounce_recipient },
 478   { "bounce_return_size_limit", vtype_int,    &bounce_return_size_limit },
 479   { "caller_gid",          vtype_gid,         &real_gid },
 480   { "caller_uid",          vtype_uid,         &real_uid },
 481   { "callout_address",     vtype_stringptr,   &callout_address },
 482   { "compile_date",        vtype_stringptr,   &version_date },
 483   { "compile_number",      vtype_stringptr,   &version_cnumber },
 484   { "config_dir",          vtype_stringptr,   &config_main_directory },
 485   { "config_file",         vtype_stringptr,   &config_main_filename },
 486   { "csa_status",          vtype_stringptr,   &csa_status },
 487 #ifdef EXPERIMENTAL_DCC
 488   { "dcc_header",          vtype_stringptr,   &dcc_header },
 489   { "dcc_result",          vtype_stringptr,   &dcc_result },
 490 #endif
 491 #ifndef DISABLE_DKIM
 492   { "dkim_algo",           vtype_dkim,        (void *)DKIM_ALGO },
 493   { "dkim_bodylength",     vtype_dkim,        (void *)DKIM_BODYLENGTH },
 494   { "dkim_canon_body",     vtype_dkim,        (void *)DKIM_CANON_BODY },
 495   { "dkim_canon_headers",  vtype_dkim,        (void *)DKIM_CANON_HEADERS },
 496   { "dkim_copiedheaders",  vtype_dkim,        (void *)DKIM_COPIEDHEADERS },
 497   { "dkim_created",        vtype_dkim,        (void *)DKIM_CREATED },
 498   { "dkim_cur_signer",     vtype_stringptr,   &dkim_cur_signer },
 499   { "dkim_domain",         vtype_stringptr,   &dkim_signing_domain },
 500   { "dkim_expires",        vtype_dkim,        (void *)DKIM_EXPIRES },
 501   { "dkim_headernames",    vtype_dkim,        (void *)DKIM_HEADERNAMES },
 502   { "dkim_identity",       vtype_dkim,        (void *)DKIM_IDENTITY },
 503   { "dkim_key_granularity",vtype_dkim,        (void *)DKIM_KEY_GRANULARITY },
 504   { "dkim_key_length",     vtype_int,         &dkim_key_length },
 505   { "dkim_key_nosubdomains",vtype_dkim,       (void *)DKIM_NOSUBDOMAINS },
 506   { "dkim_key_notes",      vtype_dkim,        (void *)DKIM_KEY_NOTES },
 507   { "dkim_key_srvtype",    vtype_dkim,        (void *)DKIM_KEY_SRVTYPE },
 508   { "dkim_key_testing",    vtype_dkim,        (void *)DKIM_KEY_TESTING },
 509   { "dkim_selector",       vtype_stringptr,   &dkim_signing_selector },
 510   { "dkim_signers",        vtype_stringptr,   &dkim_signers },
 511   { "dkim_verify_reason",  vtype_stringptr,   &dkim_verify_reason },
 512   { "dkim_verify_status",  vtype_stringptr,   &dkim_verify_status },
 513 #endif
 514 #ifdef EXPERIMENTAL_DMARC
 515   { "dmarc_ar_header",     vtype_stringptr,   &dmarc_ar_header },
 516   { "dmarc_domain_policy", vtype_stringptr,   &dmarc_domain_policy },
 517   { "dmarc_status",        vtype_stringptr,   &dmarc_status },
 518   { "dmarc_status_text",   vtype_stringptr,   &dmarc_status_text },
 519   { "dmarc_used_domain",   vtype_stringptr,   &dmarc_used_domain },
 520 #endif
 521   { "dnslist_domain",      vtype_stringptr,   &dnslist_domain },
 522   { "dnslist_matched",     vtype_stringptr,   &dnslist_matched },
 523   { "dnslist_text",        vtype_stringptr,   &dnslist_text },
 524   { "dnslist_value",       vtype_stringptr,   &dnslist_value },
 525   { "domain",              vtype_stringptr,   &deliver_domain },
 526   { "domain_data",         vtype_stringptr,   &deliver_domain_data },
 527 #ifndef DISABLE_EVENT
 528   { "event_data",          vtype_stringptr,   &event_data },
 529
 530   /*XXX want to use generic vars for as many of these as possible*/
 531   { "event_defer_errno",   vtype_int,         &event_defer_errno },
 532
 533   { "event_name",          vtype_stringptr,   &event_name },
 534 #endif
 535   { "exim_gid",            vtype_gid,         &exim_gid },
 536   { "exim_path",           vtype_stringptr,   &exim_path },
 537   { "exim_uid",            vtype_uid,         &exim_uid },
 538   { "exim_version",        vtype_stringptr,   &version_string },
 539   { "headers_added",       vtype_string_func, &fn_hdrs_added },
 540   { "home",                vtype_stringptr,   &deliver_home },
 541   { "host",                vtype_stringptr,   &deliver_host },
 542   { "host_address",        vtype_stringptr,   &deliver_host_address },
 543   { "host_data",           vtype_stringptr,   &host_data },
 544   { "host_lookup_deferred",vtype_int,         &host_lookup_deferred },
 545   { "host_lookup_failed",  vtype_int,         &host_lookup_failed },
 546   { "host_port",           vtype_int,         &deliver_host_port },
 547   { "initial_cwd",         vtype_stringptr,   &initial_cwd },
 548   { "inode",               vtype_ino,         &deliver_inode },
 549   { "interface_address",   vtype_stringptr,   &interface_address },
 550   { "interface_port",      vtype_int,         &interface_port },
 551   { "item",                vtype_stringptr,   &iterate_item },
 552   #ifdef LOOKUP_LDAP
 553   { "ldap_dn",             vtype_stringptr,   &eldap_dn },
 554   #endif
 555   { "load_average",        vtype_load_avg,    NULL },
 556   { "local_part",          vtype_stringptr,   &deliver_localpart },
 557   { "local_part_data",     vtype_stringptr,   &deliver_localpart_data },
 558   { "local_part_prefix",   vtype_stringptr,   &deliver_localpart_prefix },
 559   { "local_part_suffix",   vtype_stringptr,   &deliver_localpart_suffix },
 560   { "local_scan_data",     vtype_stringptr,   &local_scan_data },
 561   { "local_user_gid",      vtype_gid,         &local_user_gid },
 562   { "local_user_uid",      vtype_uid,         &local_user_uid },
 563   { "localhost_number",    vtype_int,         &host_number },
 564   { "log_inodes",          vtype_pinodes,     (void *)FALSE },
 565   { "log_space",           vtype_pspace,      (void *)FALSE },
 566   { "lookup_dnssec_authenticated",vtype_stringptr,&lookup_dnssec_authenticated},
 567   { "mailstore_basename",  vtype_stringptr,   &mailstore_basename },
 568 #ifdef WITH_CONTENT_SCAN
 569   { "malware_name",        vtype_stringptr,   &malware_name },
 570 #endif
 571   { "max_received_linelength", vtype_int,     &max_received_linelength },
 572   { "message_age",         vtype_int,         &message_age },
 573   { "message_body",        vtype_msgbody,     &message_body },
 574   { "message_body_end",    vtype_msgbody_end, &message_body_end },
 575   { "message_body_size",   vtype_int,         &message_body_size },
 576   { "message_exim_id",     vtype_stringptr,   &message_id },
 577   { "message_headers",     vtype_msgheaders,  NULL },
 578   { "message_headers_raw", vtype_msgheaders_raw, NULL },
 579   { "message_id",          vtype_stringptr,   &message_id },
 580   { "message_linecount",   vtype_int,         &message_linecount },
 581   { "message_size",        vtype_int,         &message_size },
 582 #ifdef SUPPORT_I18N
 583   { "message_smtputf8",    vtype_bool,        &message_smtputf8 },
 584 #endif
 585 #ifdef WITH_CONTENT_SCAN
 586   { "mime_anomaly_level",  vtype_int,         &mime_anomaly_level },
 587   { "mime_anomaly_text",   vtype_stringptr,   &mime_anomaly_text },
 588   { "mime_boundary",       vtype_stringptr,   &mime_boundary },
 589   { "mime_charset",        vtype_stringptr,   &mime_charset },
 590   { "mime_content_description", vtype_stringptr, &mime_content_description },
 591   { "mime_content_disposition", vtype_stringptr, &mime_content_disposition },
 592   { "mime_content_id",     vtype_stringptr,   &mime_content_id },
 593   { "mime_content_size",   vtype_int,         &mime_content_size },
 594   { "mime_content_transfer_encoding",vtype_stringptr, &mime_content_transfer_encoding },
 595   { "mime_content_type",   vtype_stringptr,   &mime_content_type },
 596   { "mime_decoded_filename", vtype_stringptr, &mime_decoded_filename },
 597   { "mime_filename",       vtype_stringptr,   &mime_filename },
 598   { "mime_is_coverletter", vtype_int,         &mime_is_coverletter },
 599   { "mime_is_multipart",   vtype_int,         &mime_is_multipart },
 600   { "mime_is_rfc822",      vtype_int,         &mime_is_rfc822 },
 601   { "mime_part_count",     vtype_int,         &mime_part_count },
 602 #endif
 603   { "n0",                  vtype_filter_int,  &filter_n[0] },
 604   { "n1",                  vtype_filter_int,  &filter_n[1] },
 605   { "n2",                  vtype_filter_int,  &filter_n[2] },
 606   { "n3",                  vtype_filter_int,  &filter_n[3] },
 607   { "n4",                  vtype_filter_int,  &filter_n[4] },
 608   { "n5",                  vtype_filter_int,  &filter_n[5] },
 609   { "n6",                  vtype_filter_int,  &filter_n[6] },
 610   { "n7",                  vtype_filter_int,  &filter_n[7] },
 611   { "n8",                  vtype_filter_int,  &filter_n[8] },
 612   { "n9",                  vtype_filter_int,  &filter_n[9] },
 613   { "original_domain",     vtype_stringptr,   &deliver_domain_orig },
 614   { "original_local_part", vtype_stringptr,   &deliver_localpart_orig },
 615   { "originator_gid",      vtype_gid,         &originator_gid },
 616   { "originator_uid",      vtype_uid,         &originator_uid },
 617   { "parent_domain",       vtype_stringptr,   &deliver_domain_parent },
 618   { "parent_local_part",   vtype_stringptr,   &deliver_localpart_parent },
 619   { "pid",                 vtype_pid,         NULL },
 620 #ifndef DISABLE_PRDR
 621   { "prdr_requested",      vtype_bool,        &prdr_requested },
 622 #endif
 623   { "primary_hostname",    vtype_stringptr,   &primary_hostname },
 624 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS)
 625   { "proxy_external_address",vtype_stringptr, &proxy_external_address },
 626   { "proxy_external_port", vtype_int,         &proxy_external_port },
 627   { "proxy_local_address", vtype_stringptr,   &proxy_local_address },
 628   { "proxy_local_port",    vtype_int,         &proxy_local_port },
 629   { "proxy_session",       vtype_bool,        &proxy_session },
 630 #endif
 631   { "prvscheck_address",   vtype_stringptr,   &prvscheck_address },
 632   { "prvscheck_keynum",    vtype_stringptr,   &prvscheck_keynum },
 633   { "prvscheck_result",    vtype_stringptr,   &prvscheck_result },
 634   { "qualify_domain",      vtype_stringptr,   &qualify_domain_sender },
 635   { "qualify_recipient",   vtype_stringptr,   &qualify_domain_recipient },
 636   { "queue_name",          vtype_stringptr,   &queue_name },
 637   { "rcpt_count",          vtype_int,         &rcpt_count },
 638   { "rcpt_defer_count",    vtype_int,         &rcpt_defer_count },
 639   { "rcpt_fail_count",     vtype_int,         &rcpt_fail_count },
 640   { "received_count",      vtype_int,         &received_count },
 641   { "received_for",        vtype_stringptr,   &received_for },
 642   { "received_ip_address", vtype_stringptr,   &interface_address },
 643   { "received_port",       vtype_int,         &interface_port },
 644   { "received_protocol",   vtype_stringptr,   &received_protocol },
 645   { "received_time",       vtype_int,         &received_time.tv_sec },
 646   { "recipient_data",      vtype_stringptr,   &recipient_data },
 647   { "recipient_verify_failure",vtype_stringptr,&recipient_verify_failure },
 648   { "recipients",          vtype_string_func, &fn_recipients },
 649   { "recipients_count",    vtype_int,         &recipients_count },
 650 #ifdef WITH_CONTENT_SCAN
 651   { "regex_match_string",  vtype_stringptr,   &regex_match_string },
 652 #endif
 653   { "reply_address",       vtype_reply,       NULL },
 654   { "return_path",         vtype_stringptr,   &return_path },
 655   { "return_size_limit",   vtype_int,         &bounce_return_size_limit },
 656   { "router_name",         vtype_stringptr,   &router_name },
 657   { "runrc",               vtype_int,         &runrc },
 658   { "self_hostname",       vtype_stringptr,   &self_hostname },
 659   { "sender_address",      vtype_stringptr,   &sender_address },
 660   { "sender_address_data", vtype_stringptr,   &sender_address_data },
 661   { "sender_address_domain", vtype_domain,    &sender_address },
 662   { "sender_address_local_part", vtype_localpart, &sender_address },
 663   { "sender_data",         vtype_stringptr,   &sender_data },
 664   { "sender_fullhost",     vtype_stringptr,   &sender_fullhost },
 665   { "sender_helo_dnssec",  vtype_bool,        &sender_helo_dnssec },
 666   { "sender_helo_name",    vtype_stringptr,   &sender_helo_name },
 667   { "sender_host_address", vtype_stringptr,   &sender_host_address },
 668   { "sender_host_authenticated",vtype_stringptr, &sender_host_authenticated },
 669   { "sender_host_dnssec",  vtype_bool,        &sender_host_dnssec },
 670   { "sender_host_name",    vtype_host_lookup, NULL },
 671   { "sender_host_port",    vtype_int,         &sender_host_port },
 672   { "sender_ident",        vtype_stringptr,   &sender_ident },
 673   { "sender_rate",         vtype_stringptr,   &sender_rate },
 674   { "sender_rate_limit",   vtype_stringptr,   &sender_rate_limit },
 675   { "sender_rate_period",  vtype_stringptr,   &sender_rate_period },
 676   { "sender_rcvhost",      vtype_stringptr,   &sender_rcvhost },
 677   { "sender_verify_failure",vtype_stringptr,  &sender_verify_failure },
 678   { "sending_ip_address",  vtype_stringptr,   &sending_ip_address },
 679   { "sending_port",        vtype_int,         &sending_port },
 680   { "smtp_active_hostname", vtype_stringptr,  &smtp_active_hostname },
 681   { "smtp_command",        vtype_stringptr,   &smtp_cmd_buffer },
 682   { "smtp_command_argument", vtype_stringptr, &smtp_cmd_argument },
 683   { "smtp_command_history", vtype_string_func, &smtp_cmd_hist },
 684   { "smtp_count_at_connection_start", vtype_int, &smtp_accept_count },
 685   { "smtp_notquit_reason", vtype_stringptr,   &smtp_notquit_reason },
 686   { "sn0",                 vtype_filter_int,  &filter_sn[0] },
 687   { "sn1",                 vtype_filter_int,  &filter_sn[1] },
 688   { "sn2",                 vtype_filter_int,  &filter_sn[2] },
 689   { "sn3",                 vtype_filter_int,  &filter_sn[3] },
 690   { "sn4",                 vtype_filter_int,  &filter_sn[4] },
 691   { "sn5",                 vtype_filter_int,  &filter_sn[5] },
 692   { "sn6",                 vtype_filter_int,  &filter_sn[6] },
 693   { "sn7",                 vtype_filter_int,  &filter_sn[7] },
 694   { "sn8",                 vtype_filter_int,  &filter_sn[8] },
 695   { "sn9",                 vtype_filter_int,  &filter_sn[9] },
 696 #ifdef WITH_CONTENT_SCAN
 697   { "spam_action",         vtype_stringptr,   &spam_action },
 698   { "spam_bar",            vtype_stringptr,   &spam_bar },
 699   { "spam_report",         vtype_stringptr,   &spam_report },
 700   { "spam_score",          vtype_stringptr,   &spam_score },
 701   { "spam_score_int",      vtype_stringptr,   &spam_score_int },
 702 #endif
 703 #ifdef EXPERIMENTAL_SPF
 704   { "spf_guess",           vtype_stringptr,   &spf_guess },
 705   { "spf_header_comment",  vtype_stringptr,   &spf_header_comment },
 706   { "spf_received",        vtype_stringptr,   &spf_received },
 707   { "spf_result",          vtype_stringptr,   &spf_result },
 708   { "spf_smtp_comment",    vtype_stringptr,   &spf_smtp_comment },
 709 #endif
 710   { "spool_directory",     vtype_stringptr,   &spool_directory },
 711   { "spool_inodes",        vtype_pinodes,     (void *)TRUE },
 712   { "spool_space",         vtype_pspace,      (void *)TRUE },
 713 #ifdef EXPERIMENTAL_SRS
 714   { "srs_db_address",      vtype_stringptr,   &srs_db_address },
 715   { "srs_db_key",          vtype_stringptr,   &srs_db_key },
 716   { "srs_orig_recipient",  vtype_stringptr,   &srs_orig_recipient },
 717   { "srs_orig_sender",     vtype_stringptr,   &srs_orig_sender },
 718   { "srs_recipient",       vtype_stringptr,   &srs_recipient },
 719   { "srs_status",          vtype_stringptr,   &srs_status },
 720 #endif
 721   { "thisaddress",         vtype_stringptr,   &filter_thisaddress },
 722
 723   /* The non-(in,out) variables are now deprecated */
 724   { "tls_bits",            vtype_int,         &tls_in.bits },
 725   { "tls_certificate_verified", vtype_int,    &tls_in.certificate_verified },
 726   { "tls_cipher",          vtype_stringptr,   &tls_in.cipher },
 727
 728   { "tls_in_bits",         vtype_int,         &tls_in.bits },
 729   { "tls_in_certificate_verified", vtype_int, &tls_in.certificate_verified },
 730   { "tls_in_cipher",       vtype_stringptr,   &tls_in.cipher },
 731   { "tls_in_ocsp",         vtype_int,         &tls_in.ocsp },
 732   { "tls_in_ourcert",      vtype_cert,        &tls_in.ourcert },
 733   { "tls_in_peercert",     vtype_cert,        &tls_in.peercert },
 734   { "tls_in_peerdn",       vtype_stringptr,   &tls_in.peerdn },
 735 #if defined(SUPPORT_TLS)
 736   { "tls_in_sni",          vtype_stringptr,   &tls_in.sni },
 737 #endif
 738   { "tls_out_bits",        vtype_int,         &tls_out.bits },
 739   { "tls_out_certificate_verified", vtype_int,&tls_out.certificate_verified },
 740   { "tls_out_cipher",      vtype_stringptr,   &tls_out.cipher },
 741 #ifdef EXPERIMENTAL_DANE
 742   { "tls_out_dane",        vtype_bool,        &tls_out.dane_verified },
 743 #endif
 744   { "tls_out_ocsp",        vtype_int,         &tls_out.ocsp },
 745   { "tls_out_ourcert",     vtype_cert,        &tls_out.ourcert },
 746   { "tls_out_peercert",    vtype_cert,        &tls_out.peercert },
 747   { "tls_out_peerdn",      vtype_stringptr,   &tls_out.peerdn },
 748 #if defined(SUPPORT_TLS)
 749   { "tls_out_sni",         vtype_stringptr,   &tls_out.sni },
 750 #endif
 751 #ifdef EXPERIMENTAL_DANE
 752   { "tls_out_tlsa_usage",  vtype_int,         &tls_out.tlsa_usage },
 753 #endif
 754
 755   { "tls_peerdn",          vtype_stringptr,   &tls_in.peerdn }, /* mind the alphabetical order! */
 756 #if defined(SUPPORT_TLS)
 757   { "tls_sni",             vtype_stringptr,   &tls_in.sni },    /* mind the alphabetical order! */
 758 #endif
 759
 760   { "tod_bsdinbox",        vtype_todbsdin,    NULL },
 761   { "tod_epoch",           vtype_tode,        NULL },
 762   { "tod_epoch_l",         vtype_todel,       NULL },
 763   { "tod_full",            vtype_todf,        NULL },
 764   { "tod_log",             vtype_todl,        NULL },
 765   { "tod_logfile",         vtype_todlf,       NULL },
 766   { "tod_zone",            vtype_todzone,     NULL },
 767   { "tod_zulu",            vtype_todzulu,     NULL },
 768   { "transport_name",      vtype_stringptr,   &transport_name },
 769   { "value",               vtype_stringptr,   &lookup_value },
 770   { "verify_mode",         vtype_stringptr,   &verify_mode },
 771   { "version_number",      vtype_stringptr,   &version_string },
 772   { "warn_message_delay",  vtype_stringptr,   &warnmsg_delay },
 773   { "warn_message_recipient",vtype_stringptr, &warnmsg_recipients },
 774   { "warn_message_recipients",vtype_stringptr,&warnmsg_recipients },
 775   { "warnmsg_delay",       vtype_stringptr,   &warnmsg_delay },
 776   { "warnmsg_recipient",   vtype_stringptr,   &warnmsg_recipients },
 777   { "warnmsg_recipients",  vtype_stringptr,   &warnmsg_recipients }
 778 };
 779
 780 static int var_table_size = nelem(var_table);
 781 static uschar var_buffer[256];
 782 static BOOL malformed_header;
 783
 784 /* For textual hashes */
 785
 786 static const char *hashcodes = "abcdefghijklmnopqrtsuvwxyz"
 787                                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 788                                "0123456789";
 789
 790 enum { HMAC_MD5, HMAC_SHA1 };
 791
 792 /* For numeric hashes */
 793
 794 static unsigned int prime[] = {
 795   2,   3,   5,   7,  11,  13,  17,  19,  23,  29,
 796  31,  37,  41,  43,  47,  53,  59,  61,  67,  71,
 797  73,  79,  83,  89,  97, 101, 103, 107, 109, 113};
 798
 799 /* For printing modes in symbolic form */
 800
 801 static uschar *mtable_normal[] =
 802   { US"---", US"--x", US"-w-", US"-wx", US"r--", US"r-x", US"rw-", US"rwx" };
 803
 804 static uschar *mtable_setid[] =
 805   { US"--S", US"--s", US"-wS", US"-ws", US"r-S", US"r-s", US"rwS", US"rws" };
 806
 807 static uschar *mtable_sticky[] =
 808   { US"--T", US"--t", US"-wT", US"-wt", US"r-T", US"r-t", US"rwT", US"rwt" };
 809
 810
 811
 812 /*************************************************
 813 *           Tables for UTF-8 support             *
 814 *************************************************/
 815
 816 /* Table of the number of extra characters, indexed by the first character
 817 masked with 0x3f. The highest number for a valid UTF-8 character is in fact
 818 0x3d. */
 819
 820 static uschar utf8_table1[] = {
 821   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 822   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 823   2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
 824   3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5 };
 825
 826 /* These are the masks for the data bits in the first byte of a character,
 827 indexed by the number of additional bytes. */
 828
 829 static int utf8_table2[] = { 0xff, 0x1f, 0x0f, 0x07, 0x03, 0x01};
 830
 831 /* Get the next UTF-8 character, advancing the pointer. */
 832
 833 #define GETUTF8INC(c, ptr) \
 834   c = *ptr++; \
 835   if ((c & 0xc0) == 0xc0) \
 836     { \
 837     int a = utf8_table1[c & 0x3f];  /* Number of additional bytes */ \
 838     int s = 6*a; \
 839     c = (c & utf8_table2[a]) << s; \
 840     while (a-- > 0) \
 841       { \
 842       s -= 6; \
 843       c |= (*ptr++ & 0x3f) << s; \
 844       } \
 845     }
 846
 847
 848
 849 static uschar * base32_chars = US"abcdefghijklmnopqrstuvwxyz234567";
 850
 851 /*************************************************
 852 *           Binary chop search on a table        *
 853 *************************************************/
 854
 855 /* This is used for matching expansion items and operators.
 856
 857 Arguments:
 858   name        the name that is being sought
 859   table       the table to search
 860   table_size  the number of items in the table
 861
 862 Returns:      the offset in the table, or -1
 863 */
 864
 865 static int
 866 chop_match(uschar *name, uschar **table, int table_size)
 867 {
 868 uschar **bot = table;
 869 uschar **top = table + table_size;
 870
 871 while (top > bot)
 872   {
 873   uschar **mid = bot + (top - bot)/2;
 874   int c = Ustrcmp(name, *mid);
 875   if (c == 0) return mid - table;
 876   if (c > 0) bot = mid + 1; else top = mid;
 877   }
 878
 879 return -1;
 880 }
 881
 882
 883
 884 /*************************************************
 885 *          Check a condition string              *
 886 *************************************************/
 887
 888 /* This function is called to expand a string, and test the result for a "true"
 889 or "false" value. Failure of the expansion yields FALSE; logged unless it was a
 890 forced fail or lookup defer.
 891
 892 We used to release all store used, but this is not not safe due
 893 to ${dlfunc } and ${acl }.  In any case expand_string_internal()
 894 is reasonably careful to release what it can.
 895
 896 The actual false-value tests should be replicated for ECOND_BOOL_LAX.
 897
 898 Arguments:
 899   condition     the condition string
 900   m1            text to be incorporated in panic error
 901   m2            ditto
 902
 903 Returns:        TRUE if condition is met, FALSE if not
 904 */
 905
 906 BOOL
 907 expand_check_condition(uschar *condition, uschar *m1, uschar *m2)
 908 {
 909 int rc;
 910 uschar *ss = expand_string(condition);
 911 if (ss == NULL)
 912   {
 913   if (!expand_string_forcedfail && !search_find_defer)
 914     log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand condition \"%s\" "
 915       "for %s %s: %s", condition, m1, m2, expand_string_message);
 916   return FALSE;
 917   }
 918 rc = ss[0] != 0 && Ustrcmp(ss, "0") != 0 && strcmpic(ss, US"no") != 0 &&
 919   strcmpic(ss, US"false") != 0;
 920 return rc;
 921 }
 922
 923
 924
 925
 926 /*************************************************
 927 *        Pseudo-random number generation         *
 928 *************************************************/
 929
 930 /* Pseudo-random number generation.  The result is not "expected" to be
 931 cryptographically strong but not so weak that someone will shoot themselves
 932 in the foot using it as a nonce in some email header scheme or whatever
 933 weirdness they'll twist this into.  The result should ideally handle fork().
 934
 935 However, if we're stuck unable to provide this, then we'll fall back to
 936 appallingly bad randomness.
 937
 938 If SUPPORT_TLS is defined then this will not be used except as an emergency
 939 fallback.
 940
 941 Arguments:
 942   max       range maximum
 943 Returns     a random number in range [0, max-1]
 944 */
 945
 946 #ifdef SUPPORT_TLS
 947 # define vaguely_random_number vaguely_random_number_fallback
 948 #endif
 949 int
 950 vaguely_random_number(int max)
 951 {
 952 #ifdef SUPPORT_TLS
 953 # undef vaguely_random_number
 954 #endif
 955   static pid_t pid = 0;
 956   pid_t p2;
 957 #if defined(HAVE_SRANDOM) && !defined(HAVE_SRANDOMDEV)
 958   struct timeval tv;
 959 #endif
 960
 961   p2 = getpid();
 962   if (p2 != pid)
 963     {
 964     if (pid != 0)
 965       {
 966
 967 #ifdef HAVE_ARC4RANDOM
 968       /* cryptographically strong randomness, common on *BSD platforms, not
 969       so much elsewhere.  Alas. */
 970 #ifndef NOT_HAVE_ARC4RANDOM_STIR
 971       arc4random_stir();
 972 #endif
 973 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 974 #ifdef HAVE_SRANDOMDEV
 975       /* uses random(4) for seeding */
 976       srandomdev();
 977 #else
 978       gettimeofday(&tv, NULL);
 979       srandom(tv.tv_sec | tv.tv_usec | getpid());
 980 #endif
 981 #else
 982       /* Poor randomness and no seeding here */
 983 #endif
 984
 985       }
 986     pid = p2;
 987     }
 988
 989 #ifdef HAVE_ARC4RANDOM
 990   return arc4random() % max;
 991 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 992   return random() % max;
 993 #else
 994   /* This one returns a 16-bit number, definitely not crypto-strong */
 995   return random_number(max);
 996 #endif
 997 }
 998
 999
1000
1001
1002 /*************************************************
1003 *             Pick out a name from a string      *
1004 *************************************************/
1005
1006 /* If the name is too long, it is silently truncated.
1007
1008 Arguments:
1009   name      points to a buffer into which to put the name
1010   max       is the length of the buffer
1011   s         points to the first alphabetic character of the name
1012   extras    chars other than alphanumerics to permit
1013
1014 Returns:    pointer to the first character after the name
1015
1016 Note: The test for *s != 0 in the while loop is necessary because
1017 Ustrchr() yields non-NULL if the character is zero (which is not something
1018 I expected). */
1019
1020 static const uschar *
1021 read_name(uschar *name, int max, const uschar *s, uschar *extras)
1022 {
1023 int ptr = 0;
1024 while (*s != 0 && (isalnum(*s) || Ustrchr(extras, *s) != NULL))
1025   {
1026   if (ptr < max-1) name[ptr++] = *s;
1027   s++;
1028   }
1029 name[ptr] = 0;
1030 return s;
1031 }
1032
1033
1034
1035 /*************************************************
1036 *     Pick out the rest of a header name         *
1037 *************************************************/
1038
1039 /* A variable name starting $header_ (or just $h_ for those who like
1040 abbreviations) might not be the complete header name because headers can
1041 contain any printing characters in their names, except ':'. This function is
1042 called to read the rest of the name, chop h[eader]_ off the front, and put ':'
1043 on the end, if the name was terminated by white space.
1044
1045 Arguments:
1046   name      points to a buffer in which the name read so far exists
1047   max       is the length of the buffer
1048   s         points to the first character after the name so far, i.e. the
1049             first non-alphameric character after $header_xxxxx
1050
1051 Returns:    a pointer to the first character after the header name
1052 */
1053
1054 static const uschar *
1055 read_header_name(uschar *name, int max, const uschar *s)
1056 {
1057 int prelen = Ustrchr(name, '_') - name + 1;
1058 int ptr = Ustrlen(name) - prelen;
1059 if (ptr > 0) memmove(name, name+prelen, ptr);
1060 while (mac_isgraph(*s) && *s != ':')
1061   {
1062   if (ptr < max-1) name[ptr++] = *s;
1063   s++;
1064   }
1065 if (*s == ':') s++;
1066 name[ptr++] = ':';
1067 name[ptr] = 0;
1068 return s;
1069 }
1070
1071
1072
1073 /*************************************************
1074 *           Pick out a number from a string      *
1075 *************************************************/
1076
1077 /* Arguments:
1078   n     points to an integer into which to put the number
1079   s     points to the first digit of the number
1080
1081 Returns:  a pointer to the character after the last digit
1082 */
1083 /*XXX consider expanding to int_eximarith_t.  But the test for
1084 "overbig numbers" in 0002 still needs to overflow it. */
1085
1086 static uschar *
1087 read_number(int *n, uschar *s)
1088 {
1089 *n = 0;
1090 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
1091 return s;
1092 }
1093
1094 static const uschar *
1095 read_cnumber(int *n, const uschar *s)
1096 {
1097 *n = 0;
1098 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
1099 return s;
1100 }
1101
1102
1103
1104 /*************************************************
1105 *        Extract keyed subfield from a string    *
1106 *************************************************/
1107
1108 /* The yield is in dynamic store; NULL means that the key was not found.
1109
1110 Arguments:
1111   key       points to the name of the key
1112   s         points to the string from which to extract the subfield
1113
1114 Returns:    NULL if the subfield was not found, or
1115             a pointer to the subfield's data
1116 */
1117
1118 static uschar *
1119 expand_getkeyed(uschar *key, const uschar *s)
1120 {
1121 int length = Ustrlen(key);
1122 while (isspace(*s)) s++;
1123
1124 /* Loop to search for the key */
1125
1126 while (*s != 0)
1127   {
1128   int dkeylength;
1129   uschar *data;
1130   const uschar *dkey = s;
1131
1132   while (*s != 0 && *s != '=' && !isspace(*s)) s++;
1133   dkeylength = s - dkey;
1134   while (isspace(*s)) s++;
1135   if (*s == '=') while (isspace((*(++s))));
1136
1137   data = string_dequote(&s);
1138   if (length == dkeylength && strncmpic(key, dkey, length) == 0)
1139     return data;
1140
1141   while (isspace(*s)) s++;
1142   }
1143
1144 return NULL;
1145 }
1146
1147
1148
1149 static var_entry *
1150 find_var_ent(uschar * name)
1151 {
1152 int first = 0;
1153 int last = var_table_size;
1154
1155 while (last > first)
1156   {
1157   int middle = (first + last)/2;
1158   int c = Ustrcmp(name, var_table[middle].name);
1159
1160   if (c > 0) { first = middle + 1; continue; }
1161   if (c < 0) { last = middle; continue; }
1162   return &var_table[middle];
1163   }
1164 return NULL;
1165 }
1166
1167 /*************************************************
1168 *   Extract numbered subfield from string        *
1169 *************************************************/
1170
1171 /* Extracts a numbered field from a string that is divided by tokens - for
1172 example a line from /etc/passwd is divided by colon characters.  First field is
1173 numbered one.  Negative arguments count from the right. Zero returns the whole
1174 string. Returns NULL if there are insufficient tokens in the string
1175
1176 ***WARNING***
1177 Modifies final argument - this is a dynamically generated string, so that's OK.
1178
1179 Arguments:
1180   field       number of field to be extracted,
1181                 first field = 1, whole string = 0, last field = -1
1182   separators  characters that are used to break string into tokens
1183   s           points to the string from which to extract the subfield
1184
1185 Returns:      NULL if the field was not found,
1186               a pointer to the field's data inside s (modified to add 0)
1187 */
1188
1189 static uschar *
1190 expand_gettokened (int field, uschar *separators, uschar *s)
1191 {
1192 int sep = 1;
1193 int count;
1194 uschar *ss = s;
1195 uschar *fieldtext = NULL;
1196
1197 if (field == 0) return s;
1198
1199 /* Break the line up into fields in place; for field > 0 we stop when we have
1200 done the number of fields we want. For field < 0 we continue till the end of
1201 the string, counting the number of fields. */
1202
1203 count = (field > 0)? field : INT_MAX;
1204
1205 while (count-- > 0)
1206   {
1207   size_t len;
1208
1209   /* Previous field was the last one in the string. For a positive field
1210   number, this means there are not enough fields. For a negative field number,
1211   check that there are enough, and scan back to find the one that is wanted. */
1212
1213   if (sep == 0)
1214     {
1215     if (field > 0 || (-field) > (INT_MAX - count - 1)) return NULL;
1216     if ((-field) == (INT_MAX - count - 1)) return s;
1217     while (field++ < 0)
1218       {
1219       ss--;
1220       while (ss[-1] != 0) ss--;
1221       }
1222     fieldtext = ss;
1223     break;
1224     }
1225
1226   /* Previous field was not last in the string; save its start and put a
1227   zero at its end. */
1228
1229   fieldtext = ss;
1230   len = Ustrcspn(ss, separators);
1231   sep = ss[len];
1232   ss[len] = 0;
1233   ss += len + 1;
1234   }
1235
1236 return fieldtext;
1237 }
1238
1239
1240 static uschar *
1241 expand_getlistele(int field, const uschar * list)
1242 {
1243 const uschar * tlist= list;
1244 int sep= 0;
1245 uschar dummy;
1246
1247 if(field<0)
1248   {
1249   for(field++; string_nextinlist(&tlist, &sep, &dummy, 1); ) field++;
1250   sep= 0;
1251   }
1252 if(field==0) return NULL;
1253 while(--field>0 && (string_nextinlist(&list, &sep, &dummy, 1))) ;
1254 return string_nextinlist(&list, &sep, NULL, 0);
1255 }
1256
1257
1258 /* Certificate fields, by name.  Worry about by-OID later */
1259 /* Names are chosen to not have common prefixes */
1260
1261 #ifdef SUPPORT_TLS
1262 typedef struct
1263 {
1264 uschar * name;
1265 int      namelen;
1266 uschar * (*getfn)(void * cert, uschar * mod);
1267 } certfield;
1268 static certfield certfields[] =
1269 {                       /* linear search; no special order */
1270   { US"version",         7,  &tls_cert_version },
1271   { US"serial_number",   13, &tls_cert_serial_number },
1272   { US"subject",         7,  &tls_cert_subject },
1273   { US"notbefore",       9,  &tls_cert_not_before },
1274   { US"notafter",        8,  &tls_cert_not_after },
1275   { US"issuer",          6,  &tls_cert_issuer },
1276   { US"signature",       9,  &tls_cert_signature },
1277   { US"sig_algorithm",   13, &tls_cert_signature_algorithm },
1278   { US"subj_altname",    12, &tls_cert_subject_altname },
1279   { US"ocsp_uri",        8,  &tls_cert_ocsp_uri },
1280   { US"crl_uri",         7,  &tls_cert_crl_uri },
1281 };
1282
1283 static uschar *
1284 expand_getcertele(uschar * field, uschar * certvar)
1285 {
1286 var_entry * vp;
1287 certfield * cp;
1288
1289 if (!(vp = find_var_ent(certvar)))
1290   {
1291   expand_string_message =
1292     string_sprintf("no variable named \"%s\"", certvar);
1293   return NULL;          /* Unknown variable name */
1294   }
1295 /* NB this stops us passing certs around in variable.  Might
1296 want to do that in future */
1297 if (vp->type != vtype_cert)
1298   {
1299   expand_string_message =
1300     string_sprintf("\"%s\" is not a certificate", certvar);
1301   return NULL;          /* Unknown variable name */
1302   }
1303 if (!*(void **)vp->value)
1304   return NULL;
1305
1306 if (*field >= '0' && *field <= '9')
1307   return tls_cert_ext_by_oid(*(void **)vp->value, field, 0);
1308
1309 for(cp = certfields;
1310     cp < certfields + nelem(certfields);
1311     cp++)
1312   if (Ustrncmp(cp->name, field, cp->namelen) == 0)
1313     {
1314     uschar * modifier = *(field += cp->namelen) == ','
1315       ? ++field : NULL;
1316     return (*cp->getfn)( *(void **)vp->value, modifier );
1317     }
1318
1319 expand_string_message =
1320   string_sprintf("bad field selector \"%s\" for certextract", field);
1321 return NULL;
1322 }
1323 #endif  /*SUPPORT_TLS*/
1324
1325 /*************************************************
1326 *        Extract a substring from a string       *
1327 *************************************************/
1328
1329 /* Perform the ${substr or ${length expansion operations.
1330
1331 Arguments:
1332   subject     the input string
1333   value1      the offset from the start of the input string to the start of
1334                 the output string; if negative, count from the right.
1335   value2      the length of the output string, or negative (-1) for unset
1336                 if value1 is positive, unset means "all after"
1337                 if value1 is negative, unset means "all before"
1338   len         set to the length of the returned string
1339
1340 Returns:      pointer to the output string, or NULL if there is an error
1341 */
1342
1343 static uschar *
1344 extract_substr(uschar *subject, int value1, int value2, int *len)
1345 {
1346 int sublen = Ustrlen(subject);
1347
1348 if (value1 < 0)    /* count from right */
1349   {
1350   value1 += sublen;
1351
1352   /* If the position is before the start, skip to the start, and adjust the
1353   length. If the length ends up negative, the substring is null because nothing
1354   can precede. This falls out naturally when the length is unset, meaning "all
1355   to the left". */
1356
1357   if (value1 < 0)
1358     {
1359     value2 += value1;
1360     if (value2 < 0) value2 = 0;
1361     value1 = 0;
1362     }
1363
1364   /* Otherwise an unset length => characters before value1 */
1365
1366   else if (value2 < 0)
1367     {
1368     value2 = value1;
1369     value1 = 0;
1370     }
1371   }
1372
1373 /* For a non-negative offset, if the starting position is past the end of the
1374 string, the result will be the null string. Otherwise, an unset length means
1375 "rest"; just set it to the maximum - it will be cut down below if necessary. */
1376
1377 else
1378   {
1379   if (value1 > sublen)
1380     {
1381     value1 = sublen;
1382     value2 = 0;
1383     }
1384   else if (value2 < 0) value2 = sublen;
1385   }
1386
1387 /* Cut the length down to the maximum possible for the offset value, and get
1388 the required characters. */
1389
1390 if (value1 + value2 > sublen) value2 = sublen - value1;
1391 *len = value2;
1392 return subject + value1;
1393 }
1394
1395
1396
1397
1398 /*************************************************
1399 *            Old-style hash of a string          *
1400 *************************************************/
1401
1402 /* Perform the ${hash expansion operation.
1403
1404 Arguments:
1405   subject     the input string (an expanded substring)
1406   value1      the length of the output string; if greater or equal to the
1407                 length of the input string, the input string is returned
1408   value2      the number of hash characters to use, or 26 if negative
1409   len         set to the length of the returned string
1410
1411 Returns:      pointer to the output string, or NULL if there is an error
1412 */
1413
1414 static uschar *
1415 compute_hash(uschar *subject, int value1, int value2, int *len)
1416 {
1417 int sublen = Ustrlen(subject);
1418
1419 if (value2 < 0) value2 = 26;
1420 else if (value2 > Ustrlen(hashcodes))
1421   {
1422   expand_string_message =
1423     string_sprintf("hash count \"%d\" too big", value2);
1424   return NULL;
1425   }
1426
1427 /* Calculate the hash text. We know it is shorter than the original string, so
1428 can safely place it in subject[] (we know that subject is always itself an
1429 expanded substring). */
1430
1431 if (value1 < sublen)
1432   {
1433   int c;
1434   int i = 0;
1435   int j = value1;
1436   while ((c = (subject[j])) != 0)
1437     {
1438     int shift = (c + j++) & 7;
1439     subject[i] ^= (c << shift) | (c >> (8-shift));
1440     if (++i >= value1) i = 0;
1441     }
1442   for (i = 0; i < value1; i++)
1443     subject[i] = hashcodes[(subject[i]) % value2];
1444   }
1445 else value1 = sublen;
1446
1447 *len = value1;
1448 return subject;
1449 }
1450
1451
1452
1453
1454 /*************************************************
1455 *             Numeric hash of a string           *
1456 *************************************************/
1457
1458 /* Perform the ${nhash expansion operation. The first characters of the
1459 string are treated as most important, and get the highest prime numbers.
1460
1461 Arguments:
1462   subject     the input string
1463   value1      the maximum value of the first part of the result
1464   value2      the maximum value of the second part of the result,
1465                 or negative to produce only a one-part result
1466   len         set to the length of the returned string
1467
1468 Returns:  pointer to the output string, or NULL if there is an error.
1469 */
1470
1471 static uschar *
1472 compute_nhash (uschar *subject, int value1, int value2, int *len)
1473 {
1474 uschar *s = subject;
1475 int i = 0;
1476 unsigned long int total = 0; /* no overflow */
1477
1478 while (*s != 0)
1479   {
1480   if (i == 0) i = nelem(prime) - 1;
1481   total += prime[i--] * (unsigned int)(*s++);
1482   }
1483
1484 /* If value2 is unset, just compute one number */
1485
1486 if (value2 < 0)
1487   s = string_sprintf("%lu", total % value1);
1488
1489 /* Otherwise do a div/mod hash */
1490
1491 else
1492   {
1493   total = total % (value1 * value2);
1494   s = string_sprintf("%lu/%lu", total/value2, total % value2);
1495   }
1496
1497 *len = Ustrlen(s);
1498 return s;
1499 }
1500
1501
1502
1503
1504
1505 /*************************************************
1506 *     Find the value of a header or headers      *
1507 *************************************************/
1508
1509 /* Multiple instances of the same header get concatenated, and this function
1510 can also return a concatenation of all the header lines. When concatenating
1511 specific headers that contain lists of addresses, a comma is inserted between
1512 them. Otherwise we use a straight concatenation. Because some messages can have
1513 pathologically large number of lines, there is a limit on the length that is
1514 returned. Also, to avoid massive store use which would result from using
1515 string_cat() as it copies and extends strings, we do a preliminary pass to find
1516 out exactly how much store will be needed. On "normal" messages this will be
1517 pretty trivial.
1518
1519 Arguments:
1520   name          the name of the header, without the leading $header_ or $h_,
1521                 or NULL if a concatenation of all headers is required
1522   exists_only   TRUE if called from a def: test; don't need to build a string;
1523                 just return a string that is not "" and not "0" if the header
1524                 exists
1525   newsize       return the size of memory block that was obtained; may be NULL
1526                 if exists_only is TRUE
1527   want_raw      TRUE if called for $rh_ or $rheader_ variables; no processing,
1528                 other than concatenating, will be done on the header. Also used
1529                 for $message_headers_raw.
1530   charset       name of charset to translate MIME words to; used only if
1531                 want_raw is false; if NULL, no translation is done (this is
1532                 used for $bh_ and $bheader_)
1533
1534 Returns:        NULL if the header does not exist, else a pointer to a new
1535                 store block
1536 */
1537
1538 static uschar *
1539 find_header(uschar *name, BOOL exists_only, int *newsize, BOOL want_raw,
1540   uschar *charset)
1541 {
1542 BOOL found = name == NULL;
1543 int comma = 0;
1544 int len = found? 0 : Ustrlen(name);
1545 int i;
1546 uschar *yield = NULL;
1547 uschar *ptr = NULL;
1548
1549 /* Loop for two passes - saves code repetition */
1550
1551 for (i = 0; i < 2; i++)
1552   {
1553   int size = 0;
1554   header_line *h;
1555
1556   for (h = header_list; size < header_insert_maxlen && h; h = h->next)
1557     if (h->type != htype_old && h->text)  /* NULL => Received: placeholder */
1558       if (!name || (len <= h->slen && strncmpic(name, h->text, len) == 0))
1559         {
1560         int ilen;
1561         uschar *t;
1562
1563         if (exists_only) return US"1";      /* don't need actual string */
1564         found = TRUE;
1565         t = h->text + len;                  /* text to insert */
1566         if (!want_raw)                      /* unless wanted raw, */
1567           while (isspace(*t)) t++;          /* remove leading white space */
1568         ilen = h->slen - (t - h->text);     /* length to insert */
1569
1570         /* Unless wanted raw, remove trailing whitespace, including the
1571         newline. */
1572
1573         if (!want_raw)
1574           while (ilen > 0 && isspace(t[ilen-1])) ilen--;
1575
1576         /* Set comma = 1 if handling a single header and it's one of those
1577         that contains an address list, except when asked for raw headers. Only
1578         need to do this once. */
1579
1580         if (!want_raw && name && comma == 0 &&
1581             Ustrchr("BCFRST", h->type) != NULL)
1582           comma = 1;
1583
1584         /* First pass - compute total store needed; second pass - compute
1585         total store used, including this header. */
1586
1587         size += ilen + comma + 1;  /* +1 for the newline */
1588
1589         /* Second pass - concatenate the data, up to a maximum. Note that
1590         the loop stops when size hits the limit. */
1591
1592         if (i != 0)
1593           {
1594           if (size > header_insert_maxlen)
1595             {
1596             ilen -= size - header_insert_maxlen - 1;
1597             comma = 0;
1598             }
1599           Ustrncpy(ptr, t, ilen);
1600           ptr += ilen;
1601
1602           /* For a non-raw header, put in the comma if needed, then add
1603           back the newline we removed above, provided there was some text in
1604           the header. */
1605
1606           if (!want_raw && ilen > 0)
1607             {
1608             if (comma != 0) *ptr++ = ',';
1609             *ptr++ = '\n';
1610             }
1611           }
1612         }
1613
1614   /* At end of first pass, return NULL if no header found. Then truncate size
1615   if necessary, and get the buffer to hold the data, returning the buffer size.
1616   */
1617
1618   if (i == 0)
1619     {
1620     if (!found) return NULL;
1621     if (size > header_insert_maxlen) size = header_insert_maxlen;
1622     *newsize = size + 1;
1623     ptr = yield = store_get(*newsize);
1624     }
1625   }
1626
1627 /* That's all we do for raw header expansion. */
1628
1629 if (want_raw)
1630   *ptr = 0;
1631
1632 /* Otherwise, remove a final newline and a redundant added comma. Then we do
1633 RFC 2047 decoding, translating the charset if requested. The rfc2047_decode2()
1634 function can return an error with decoded data if the charset translation
1635 fails. If decoding fails, it returns NULL. */
1636
1637 else
1638   {
1639   uschar *decoded, *error;
1640   if (ptr > yield && ptr[-1] == '\n') ptr--;
1641   if (ptr > yield && comma != 0 && ptr[-1] == ',') ptr--;
1642   *ptr = 0;
1643   decoded = rfc2047_decode2(yield, check_rfc2047_length, charset, '?', NULL,
1644     newsize, &error);
1645   if (error != NULL)
1646     {
1647     DEBUG(D_any) debug_printf("*** error in RFC 2047 decoding: %s\n"
1648       "    input was: %s\n", error, yield);
1649     }
1650   if (decoded != NULL) yield = decoded;
1651   }
1652
1653 return yield;
1654 }
1655
1656
1657
1658
1659 /*************************************************
1660 *               Return list of recipients        *
1661 *************************************************/
1662 /* A recipients list is available only during system message filtering,
1663 during ACL processing after DATA, and while expanding pipe commands
1664 generated from a system filter, but not elsewhere. */
1665
1666 static uschar *
1667 fn_recipients(void)
1668 {
1669 gstring * g = NULL;
1670 int i;
1671
1672 if (!enable_dollar_recipients) return NULL;
1673
1674 for (i = 0; i < recipients_count; i++)
1675   {
1676   /*XXX variant of list_appendele? */
1677   if (i != 0) g = string_catn(g, US", ", 2);
1678   g = string_cat(g, recipients_list[i].address);
1679   }
1680 return string_from_gstring(g);
1681 }
1682
1683
1684 /*************************************************
1685 *               Find value of a variable         *
1686 *************************************************/
1687
1688 /* The table of variables is kept in alphabetic order, so we can search it
1689 using a binary chop. The "choplen" variable is nothing to do with the binary
1690 chop.
1691
1692 Arguments:
1693   name          the name of the variable being sought
1694   exists_only   TRUE if this is a def: test; passed on to find_header()
1695   skipping      TRUE => skip any processing evaluation; this is not the same as
1696                   exists_only because def: may test for values that are first
1697                   evaluated here
1698   newsize       pointer to an int which is initially zero; if the answer is in
1699                 a new memory buffer, *newsize is set to its size
1700
1701 Returns:        NULL if the variable does not exist, or
1702                 a pointer to the variable's contents, or
1703                 something non-NULL if exists_only is TRUE
1704 */
1705
1706 static uschar *
1707 find_variable(uschar *name, BOOL exists_only, BOOL skipping, int *newsize)
1708 {
1709 var_entry * vp;
1710 uschar *s, *domain;
1711 uschar **ss;
1712 void * val;
1713
1714 /* Handle ACL variables, whose names are of the form acl_cxxx or acl_mxxx.
1715 Originally, xxx had to be a number in the range 0-9 (later 0-19), but from
1716 release 4.64 onwards arbitrary names are permitted, as long as the first 5
1717 characters are acl_c or acl_m and the sixth is either a digit or an underscore
1718 (this gave backwards compatibility at the changeover). There may be built-in
1719 variables whose names start acl_ but they should never start in this way. This
1720 slightly messy specification is a consequence of the history, needless to say.
1721
1722 If an ACL variable does not exist, treat it as empty, unless strict_acl_vars is
1723 set, in which case give an error. */
1724
1725 if ((Ustrncmp(name, "acl_c", 5) == 0 || Ustrncmp(name, "acl_m", 5) == 0) &&
1726      !isalpha(name[5]))
1727   {
1728   tree_node *node =
1729     tree_search((name[4] == 'c')? acl_var_c : acl_var_m, name + 4);
1730   return node ? node->data.ptr : strict_acl_vars ? NULL : US"";
1731   }
1732
1733 /* Handle $auth<n> variables. */
1734
1735 if (Ustrncmp(name, "auth", 4) == 0)
1736   {
1737   uschar *endptr;
1738   int n = Ustrtoul(name + 4, &endptr, 10);
1739   if (*endptr == 0 && n != 0 && n <= AUTH_VARS)
1740     return !auth_vars[n-1] ? US"" : auth_vars[n-1];
1741   }
1742 else if (Ustrncmp(name, "regex", 5) == 0)
1743   {
1744   uschar *endptr;
1745   int n = Ustrtoul(name + 5, &endptr, 10);
1746   if (*endptr == 0 && n != 0 && n <= REGEX_VARS)
1747     return !regex_vars[n-1] ? US"" : regex_vars[n-1];
1748   }
1749
1750 /* For all other variables, search the table */
1751
1752 if (!(vp = find_var_ent(name)))
1753   return NULL;          /* Unknown variable name */
1754
1755 /* Found an existing variable. If in skipping state, the value isn't needed,
1756 and we want to avoid processing (such as looking up the host name). */
1757
1758 if (skipping)
1759   return US"";
1760
1761 val = vp->value;
1762 switch (vp->type)
1763   {
1764   case vtype_filter_int:
1765     if (!filter_running) return NULL;
1766     /* Fall through */
1767     /* VVVVVVVVVVVV */
1768   case vtype_int:
1769     sprintf(CS var_buffer, "%d", *(int *)(val)); /* Integer */
1770     return var_buffer;
1771
1772   case vtype_ino:
1773     sprintf(CS var_buffer, "%ld", (long int)(*(ino_t *)(val))); /* Inode */
1774     return var_buffer;
1775
1776   case vtype_gid:
1777     sprintf(CS var_buffer, "%ld", (long int)(*(gid_t *)(val))); /* gid */
1778     return var_buffer;
1779
1780   case vtype_uid:
1781     sprintf(CS var_buffer, "%ld", (long int)(*(uid_t *)(val))); /* uid */
1782     return var_buffer;
1783
1784   case vtype_bool:
1785     sprintf(CS var_buffer, "%s", *(BOOL *)(val) ? "yes" : "no"); /* bool */
1786     return var_buffer;
1787
1788   case vtype_stringptr:                      /* Pointer to string */
1789     return (s = *((uschar **)(val))) ? s : US"";
1790
1791   case vtype_pid:
1792     sprintf(CS var_buffer, "%d", (int)getpid()); /* pid */
1793     return var_buffer;
1794
1795   case vtype_load_avg:
1796     sprintf(CS var_buffer, "%d", OS_GETLOADAVG()); /* load_average */
1797     return var_buffer;
1798
1799   case vtype_host_lookup:                    /* Lookup if not done so */
1800     if (sender_host_name == NULL && sender_host_address != NULL &&
1801         !host_lookup_failed && host_name_lookup() == OK)
1802       host_build_sender_fullhost();
1803     return (sender_host_name == NULL)? US"" : sender_host_name;
1804
1805   case vtype_localpart:                      /* Get local part from address */
1806     s = *((uschar **)(val));
1807     if (s == NULL) return US"";
1808     domain = Ustrrchr(s, '@');
1809     if (domain == NULL) return s;
1810     if (domain - s > sizeof(var_buffer) - 1)
1811       log_write(0, LOG_MAIN|LOG_PANIC_DIE, "local part longer than " SIZE_T_FMT
1812           " in string expansion", sizeof(var_buffer));
1813     Ustrncpy(var_buffer, s, domain - s);
1814     var_buffer[domain - s] = 0;
1815     return var_buffer;
1816
1817   case vtype_domain:                         /* Get domain from address */
1818     s = *((uschar **)(val));
1819     if (s == NULL) return US"";
1820     domain = Ustrrchr(s, '@');
1821     return (domain == NULL)? US"" : domain + 1;
1822
1823   case vtype_msgheaders:
1824     return find_header(NULL, exists_only, newsize, FALSE, NULL);
1825
1826   case vtype_msgheaders_raw:
1827     return find_header(NULL, exists_only, newsize, TRUE, NULL);
1828
1829   case vtype_msgbody:                        /* Pointer to msgbody string */
1830   case vtype_msgbody_end:                    /* Ditto, the end of the msg */
1831     ss = (uschar **)(val);
1832     if (!*ss && deliver_datafile >= 0)  /* Read body when needed */
1833       {
1834       uschar *body;
1835       off_t start_offset = SPOOL_DATA_START_OFFSET;
1836       int len = message_body_visible;
1837       if (len > message_size) len = message_size;
1838       *ss = body = store_malloc(len+1);
1839       body[0] = 0;
1840       if (vp->type == vtype_msgbody_end)
1841         {
1842         struct stat statbuf;
1843         if (fstat(deliver_datafile, &statbuf) == 0)
1844           {
1845           start_offset = statbuf.st_size - len;
1846           if (start_offset < SPOOL_DATA_START_OFFSET)
1847             start_offset = SPOOL_DATA_START_OFFSET;
1848           }
1849         }
1850       if (lseek(deliver_datafile, start_offset, SEEK_SET) < 0)
1851         log_write(0, LOG_MAIN|LOG_PANIC_DIE, "deliver_datafile lseek: %s",
1852           strerror(errno));
1853       len = read(deliver_datafile, body, len);
1854       if (len > 0)
1855         {
1856         body[len] = 0;
1857         if (message_body_newlines)   /* Separate loops for efficiency */
1858           while (len > 0)
1859             { if (body[--len] == 0) body[len] = ' '; }
1860         else
1861           while (len > 0)
1862             { if (body[--len] == '\n' || body[len] == 0) body[len] = ' '; }
1863         }
1864       }
1865     return *ss ? *ss : US"";
1866
1867   case vtype_todbsdin:                       /* BSD inbox time of day */
1868     return tod_stamp(tod_bsdin);
1869
1870   case vtype_tode:                           /* Unix epoch time of day */
1871     return tod_stamp(tod_epoch);
1872
1873   case vtype_todel:                          /* Unix epoch/usec time of day */
1874     return tod_stamp(tod_epoch_l);
1875
1876   case vtype_todf:                           /* Full time of day */
1877     return tod_stamp(tod_full);
1878
1879   case vtype_todl:                           /* Log format time of day */
1880     return tod_stamp(tod_log_bare);            /* (without timezone) */
1881
1882   case vtype_todzone:                        /* Time zone offset only */
1883     return tod_stamp(tod_zone);
1884
1885   case vtype_todzulu:                        /* Zulu time */
1886     return tod_stamp(tod_zulu);
1887
1888   case vtype_todlf:                          /* Log file datestamp tod */
1889     return tod_stamp(tod_log_datestamp_daily);
1890
1891   case vtype_reply:                          /* Get reply address */
1892     s = find_header(US"reply-to:", exists_only, newsize, TRUE,
1893       headers_charset);
1894     if (s != NULL) while (isspace(*s)) s++;
1895     if (s == NULL || *s == 0)
1896       {
1897       *newsize = 0;                            /* For the *s==0 case */
1898       s = find_header(US"from:", exists_only, newsize, TRUE, headers_charset);
1899       }
1900     if (s != NULL)
1901       {
1902       uschar *t;
1903       while (isspace(*s)) s++;
1904       for (t = s; *t != 0; t++) if (*t == '\n') *t = ' ';
1905       while (t > s && isspace(t[-1])) t--;
1906       *t = 0;
1907       }
1908     return (s == NULL)? US"" : s;
1909
1910   case vtype_string_func:
1911     {
1912     uschar * (*fn)() = val;
1913     return fn();
1914     }
1915
1916   case vtype_pspace:
1917     {
1918     int inodes;
1919     sprintf(CS var_buffer, "%d",
1920       receive_statvfs(val == (void *)TRUE, &inodes));
1921     }
1922   return var_buffer;
1923
1924   case vtype_pinodes:
1925     {
1926     int inodes;
1927     (void) receive_statvfs(val == (void *)TRUE, &inodes);
1928     sprintf(CS var_buffer, "%d", inodes);
1929     }
1930   return var_buffer;
1931
1932   case vtype_cert:
1933     return *(void **)val ? US"<cert>" : US"";
1934
1935 #ifndef DISABLE_DKIM
1936   case vtype_dkim:
1937     return dkim_exim_expand_query((int)(long)val);
1938 #endif
1939
1940   }
1941
1942 return NULL;  /* Unknown variable. Silences static checkers. */
1943 }
1944
1945
1946
1947
1948 void
1949 modify_variable(uschar *name, void * value)
1950 {
1951 var_entry * vp;
1952 if ((vp = find_var_ent(name))) vp->value = value;
1953 return;          /* Unknown variable name, fail silently */
1954 }
1955
1956
1957
1958
1959
1960
1961 /*************************************************
1962 *           Read and expand substrings           *
1963 *************************************************/
1964
1965 /* This function is called to read and expand argument substrings for various
1966 expansion items. Some have a minimum requirement that is less than the maximum;
1967 in these cases, the first non-present one is set to NULL.
1968
1969 Arguments:
1970   sub        points to vector of pointers to set
1971   n          maximum number of substrings
1972   m          minimum required
1973   sptr       points to current string pointer
1974   skipping   the skipping flag
1975   check_end  if TRUE, check for final '}'
1976   name       name of item, for error message
1977   resetok    if not NULL, pointer to flag - write FALSE if unsafe to reset
1978              the store.
1979
1980 Returns:     0 OK; string pointer updated
1981              1 curly bracketing error (too few arguments)
1982              2 too many arguments (only if check_end is set); message set
1983              3 other error (expansion failure)
1984 */
1985
1986 static int
1987 read_subs(uschar **sub, int n, int m, const uschar **sptr, BOOL skipping,
1988   BOOL check_end, uschar *name, BOOL *resetok)
1989 {
1990 int i;
1991 const uschar *s = *sptr;
1992
1993 while (isspace(*s)) s++;
1994 for (i = 0; i < n; i++)
1995   {
1996   if (*s != '{')
1997     {
1998     if (i < m)
1999       {
2000       expand_string_message = string_sprintf("Not enough arguments for '%s' "
2001         "(min is %d)", name, m);
2002       return 1;
2003       }
2004     sub[i] = NULL;
2005     break;
2006     }
2007   if (!(sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, resetok)))
2008     return 3;
2009   if (*s++ != '}') return 1;
2010   while (isspace(*s)) s++;
2011   }
2012 if (check_end && *s++ != '}')
2013   {
2014   if (s[-1] == '{')
2015     {
2016     expand_string_message = string_sprintf("Too many arguments for '%s' "
2017       "(max is %d)", name, n);
2018     return 2;
2019     }
2020   expand_string_message = string_sprintf("missing '}' after '%s'", name);
2021   return 1;
2022   }
2023
2024 *sptr = s;
2025 return 0;
2026 }
2027
2028
2029
2030
2031 /*************************************************
2032 *     Elaborate message for bad variable         *
2033 *************************************************/
2034
2035 /* For the "unknown variable" message, take a look at the variable's name, and
2036 give additional information about possible ACL variables. The extra information
2037 is added on to expand_string_message.
2038
2039 Argument:   the name of the variable
2040 Returns:    nothing
2041 */
2042
2043 static void
2044 check_variable_error_message(uschar *name)
2045 {
2046 if (Ustrncmp(name, "acl_", 4) == 0)
2047   expand_string_message = string_sprintf("%s (%s)", expand_string_message,
2048     (name[4] == 'c' || name[4] == 'm')?
2049       (isalpha(name[5])?
2050         US"6th character of a user-defined ACL variable must be a digit or underscore" :
2051         US"strict_acl_vars is set"    /* Syntax is OK, it has to be this */
2052       ) :
2053       US"user-defined ACL variables must start acl_c or acl_m");
2054 }
2055
2056
2057
2058 /*
2059 Load args from sub array to globals, and call acl_check().
2060 Sub array will be corrupted on return.
2061
2062 Returns:       OK         access is granted by an ACCEPT verb
2063                DISCARD    access is (apparently) granted by a DISCARD verb
2064                FAIL       access is denied
2065                FAIL_DROP  access is denied; drop the connection
2066                DEFER      can't tell at the moment
2067                ERROR      disaster
2068 */
2069 static int
2070 eval_acl(uschar ** sub, int nsub, uschar ** user_msgp)
2071 {
2072 int i;
2073 int sav_narg = acl_narg;
2074 int ret;
2075 uschar * dummy_logmsg;
2076 extern int acl_where;
2077
2078 if(--nsub > nelem(acl_arg)) nsub = nelem(acl_arg);
2079 for (i = 0; i < nsub && sub[i+1]; i++)
2080   {
2081   uschar * tmp = acl_arg[i];
2082   acl_arg[i] = sub[i+1];        /* place callers args in the globals */
2083   sub[i+1] = tmp;               /* stash the old args using our caller's storage */
2084   }
2085 acl_narg = i;
2086 while (i < nsub)
2087   {
2088   sub[i+1] = acl_arg[i];
2089   acl_arg[i++] = NULL;
2090   }
2091
2092 DEBUG(D_expand)
2093   debug_printf_indent("expanding: acl: %s  arg: %s%s\n",
2094     sub[0],
2095     acl_narg>0 ? acl_arg[0] : US"<none>",
2096     acl_narg>1 ? " +more"   : "");
2097
2098 ret = acl_eval(acl_where, sub[0], user_msgp, &dummy_logmsg);
2099
2100 for (i = 0; i < nsub; i++)
2101   acl_arg[i] = sub[i+1];        /* restore old args */
2102 acl_narg = sav_narg;
2103
2104 return ret;
2105 }
2106
2107
2108
2109
2110 /*************************************************
2111 *        Read and evaluate a condition           *
2112 *************************************************/
2113
2114 /*
2115 Arguments:
2116   s        points to the start of the condition text
2117   resetok  points to a BOOL which is written false if it is unsafe to
2118            free memory. Certain condition types (acl) may have side-effect
2119            allocation which must be preserved.
2120   yield    points to a BOOL to hold the result of the condition test;
2121            if NULL, we are just reading through a condition that is
2122            part of an "or" combination to check syntax, or in a state
2123            where the answer isn't required
2124
2125 Returns:   a pointer to the first character after the condition, or
2126            NULL after an error
2127 */
2128
2129 static const uschar *
2130 eval_condition(const uschar *s, BOOL *resetok, BOOL *yield)
2131 {
2132 BOOL testfor = TRUE;
2133 BOOL tempcond, combined_cond;
2134 BOOL *subcondptr;
2135 BOOL sub2_honour_dollar = TRUE;
2136 int i, rc, cond_type, roffset;
2137 int_eximarith_t num[2];
2138 struct stat statbuf;
2139 uschar name[256];
2140 const uschar *sub[10];
2141
2142 const pcre *re;
2143 const uschar *rerror;
2144
2145 for (;;)
2146   {
2147   while (isspace(*s)) s++;
2148   if (*s == '!') { testfor = !testfor; s++; } else break;
2149   }
2150
2151 /* Numeric comparisons are symbolic */
2152
2153 if (*s == '=' || *s == '>' || *s == '<')
2154   {
2155   int p = 0;
2156   name[p++] = *s++;
2157   if (*s == '=')
2158     {
2159     name[p++] = '=';
2160     s++;
2161     }
2162   name[p] = 0;
2163   }
2164
2165 /* All other conditions are named */
2166
2167 else s = read_name(name, 256, s, US"_");
2168
2169 /* If we haven't read a name, it means some non-alpha character is first. */
2170
2171 if (name[0] == 0)
2172   {
2173   expand_string_message = string_sprintf("condition name expected, "
2174     "but found \"%.16s\"", s);
2175   return NULL;
2176   }
2177
2178 /* Find which condition we are dealing with, and switch on it */
2179
2180 cond_type = chop_match(name, cond_table, nelem(cond_table));
2181 switch(cond_type)
2182   {
2183   /* def: tests for a non-empty variable, or for the existence of a header. If
2184   yield == NULL we are in a skipping state, and don't care about the answer. */
2185
2186   case ECOND_DEF:
2187   if (*s != ':')
2188     {
2189     expand_string_message = US"\":\" expected after \"def\"";
2190     return NULL;
2191     }
2192
2193   s = read_name(name, 256, s+1, US"_");
2194
2195   /* Test for a header's existence. If the name contains a closing brace
2196   character, this may be a user error where the terminating colon has been
2197   omitted. Set a flag to adjust a subsequent error message in this case. */
2198
2199   if (Ustrncmp(name, "h_", 2) == 0 ||
2200       Ustrncmp(name, "rh_", 3) == 0 ||
2201       Ustrncmp(name, "bh_", 3) == 0 ||
2202       Ustrncmp(name, "header_", 7) == 0 ||
2203       Ustrncmp(name, "rheader_", 8) == 0 ||
2204       Ustrncmp(name, "bheader_", 8) == 0)
2205     {
2206     s = read_header_name(name, 256, s);
2207     /* {-for-text-editors */
2208     if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
2209     if (yield != NULL) *yield =
2210       (find_header(name, TRUE, NULL, FALSE, NULL) != NULL) == testfor;
2211     }
2212
2213   /* Test for a variable's having a non-empty value. A non-existent variable
2214   causes an expansion failure. */
2215
2216   else
2217     {
2218     uschar *value = find_variable(name, TRUE, yield == NULL, NULL);
2219     if (value == NULL)
2220       {
2221       expand_string_message = (name[0] == 0)?
2222         string_sprintf("variable name omitted after \"def:\"") :
2223         string_sprintf("unknown variable \"%s\" after \"def:\"", name);
2224       check_variable_error_message(name);
2225       return NULL;
2226       }
2227     if (yield != NULL) *yield = (value[0] != 0) == testfor;
2228     }
2229
2230   return s;
2231
2232
2233   /* first_delivery tests for first delivery attempt */
2234
2235   case ECOND_FIRST_DELIVERY:
2236   if (yield != NULL) *yield = deliver_firsttime == testfor;
2237   return s;
2238
2239
2240   /* queue_running tests for any process started by a queue runner */
2241
2242   case ECOND_QUEUE_RUNNING:
2243   if (yield != NULL) *yield = (queue_run_pid != (pid_t)0) == testfor;
2244   return s;
2245
2246
2247   /* exists:  tests for file existence
2248        isip:  tests for any IP address
2249       isip4:  tests for an IPv4 address
2250       isip6:  tests for an IPv6 address
2251         pam:  does PAM authentication
2252      radius:  does RADIUS authentication
2253    ldapauth:  does LDAP authentication
2254     pwcheck:  does Cyrus SASL pwcheck authentication
2255   */
2256
2257   case ECOND_EXISTS:
2258   case ECOND_ISIP:
2259   case ECOND_ISIP4:
2260   case ECOND_ISIP6:
2261   case ECOND_PAM:
2262   case ECOND_RADIUS:
2263   case ECOND_LDAPAUTH:
2264   case ECOND_PWCHECK:
2265
2266   while (isspace(*s)) s++;
2267   if (*s != '{') goto COND_FAILED_CURLY_START;          /* }-for-text-editors */
2268
2269   sub[0] = expand_string_internal(s+1, TRUE, &s, yield == NULL, TRUE, resetok);
2270   if (sub[0] == NULL) return NULL;
2271   /* {-for-text-editors */
2272   if (*s++ != '}') goto COND_FAILED_CURLY_END;
2273
2274   if (yield == NULL) return s;   /* No need to run the test if skipping */
2275
2276   switch(cond_type)
2277     {
2278     case ECOND_EXISTS:
2279     if ((expand_forbid & RDO_EXISTS) != 0)
2280       {
2281       expand_string_message = US"File existence tests are not permitted";
2282       return NULL;
2283       }
2284     *yield = (Ustat(sub[0], &statbuf) == 0) == testfor;
2285     break;
2286
2287     case ECOND_ISIP:
2288     case ECOND_ISIP4:
2289     case ECOND_ISIP6:
2290     rc = string_is_ip_address(sub[0], NULL);
2291     *yield = ((cond_type == ECOND_ISIP)? (rc != 0) :
2292              (cond_type == ECOND_ISIP4)? (rc == 4) : (rc == 6)) == testfor;
2293     break;
2294
2295     /* Various authentication tests - all optionally compiled */
2296
2297     case ECOND_PAM:
2298     #ifdef SUPPORT_PAM
2299     rc = auth_call_pam(sub[0], &expand_string_message);
2300     goto END_AUTH;
2301     #else
2302     goto COND_FAILED_NOT_COMPILED;
2303     #endif  /* SUPPORT_PAM */
2304
2305     case ECOND_RADIUS:
2306     #ifdef RADIUS_CONFIG_FILE
2307     rc = auth_call_radius(sub[0], &expand_string_message);
2308     goto END_AUTH;
2309     #else
2310     goto COND_FAILED_NOT_COMPILED;
2311     #endif  /* RADIUS_CONFIG_FILE */
2312
2313     case ECOND_LDAPAUTH:
2314     #ifdef LOOKUP_LDAP
2315       {
2316       /* Just to keep the interface the same */
2317       BOOL do_cache;
2318       int old_pool = store_pool;
2319       store_pool = POOL_SEARCH;
2320       rc = eldapauth_find((void *)(-1), NULL, sub[0], Ustrlen(sub[0]), NULL,
2321         &expand_string_message, &do_cache);
2322       store_pool = old_pool;
2323       }
2324     goto END_AUTH;
2325     #else
2326     goto COND_FAILED_NOT_COMPILED;
2327     #endif  /* LOOKUP_LDAP */
2328
2329     case ECOND_PWCHECK:
2330     #ifdef CYRUS_PWCHECK_SOCKET
2331     rc = auth_call_pwcheck(sub[0], &expand_string_message);
2332     goto END_AUTH;
2333     #else
2334     goto COND_FAILED_NOT_COMPILED;
2335     #endif  /* CYRUS_PWCHECK_SOCKET */
2336
2337     #if defined(SUPPORT_PAM) || defined(RADIUS_CONFIG_FILE) || \
2338         defined(LOOKUP_LDAP) || defined(CYRUS_PWCHECK_SOCKET)
2339     END_AUTH:
2340     if (rc == ERROR || rc == DEFER) return NULL;
2341     *yield = (rc == OK) == testfor;
2342     #endif
2343     }
2344   return s;
2345
2346
2347   /* call ACL (in a conditional context).  Accept true, deny false.
2348   Defer is a forced-fail.  Anything set by message= goes to $value.
2349   Up to ten parameters are used; we use the braces round the name+args
2350   like the saslauthd condition does, to permit a variable number of args.
2351   See also the expansion-item version EITEM_ACL and the traditional
2352   acl modifier ACLC_ACL.
2353   Since the ACL may allocate new global variables, tell our caller to not
2354   reclaim memory.
2355   */
2356
2357   case ECOND_ACL:
2358     /* ${if acl {{name}{arg1}{arg2}...}  {yes}{no}} */
2359     {
2360     uschar *sub[10];
2361     uschar *user_msg;
2362     BOOL cond = FALSE;
2363
2364     while (isspace(*s)) s++;
2365     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /*}*/
2366
2367     switch(read_subs(sub, nelem(sub), 1,
2368       &s, yield == NULL, TRUE, US"acl", resetok))
2369       {
2370       case 1: expand_string_message = US"too few arguments or bracketing "
2371         "error for acl";
2372       case 2:
2373       case 3: return NULL;
2374       }
2375
2376     if (yield != NULL)
2377       {
2378       *resetok = FALSE; /* eval_acl() might allocate; do not reclaim */
2379       switch(eval_acl(sub, nelem(sub), &user_msg))
2380         {
2381         case OK:
2382           cond = TRUE;
2383         case FAIL:
2384           lookup_value = NULL;
2385           if (user_msg)
2386             lookup_value = string_copy(user_msg);
2387           *yield = cond == testfor;
2388           break;
2389
2390         case DEFER:
2391           expand_string_forcedfail = TRUE;
2392           /*FALLTHROUGH*/
2393         default:
2394           expand_string_message = string_sprintf("error from acl \"%s\"", sub[0]);
2395           return NULL;
2396         }
2397       }
2398     return s;
2399     }
2400
2401
2402   /* saslauthd: does Cyrus saslauthd authentication. Four parameters are used:
2403
2404      ${if saslauthd {{username}{password}{service}{realm}}  {yes}{no}}
2405
2406   However, the last two are optional. That is why the whole set is enclosed
2407   in their own set of braces. */
2408
2409   case ECOND_SASLAUTHD:
2410 #ifndef CYRUS_SASLAUTHD_SOCKET
2411     goto COND_FAILED_NOT_COMPILED;
2412 #else
2413     {
2414     uschar *sub[4];
2415     while (isspace(*s)) s++;
2416     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2417     switch(read_subs(sub, nelem(sub), 2, &s, yield == NULL, TRUE, US"saslauthd",
2418                     resetok))
2419       {
2420       case 1: expand_string_message = US"too few arguments or bracketing "
2421         "error for saslauthd";
2422       case 2:
2423       case 3: return NULL;
2424       }
2425     if (sub[2] == NULL) sub[3] = NULL;  /* realm if no service */
2426     if (yield != NULL)
2427       {
2428       int rc = auth_call_saslauthd(sub[0], sub[1], sub[2], sub[3],
2429         &expand_string_message);
2430       if (rc == ERROR || rc == DEFER) return NULL;
2431       *yield = (rc == OK) == testfor;
2432       }
2433     return s;
2434     }
2435 #endif /* CYRUS_SASLAUTHD_SOCKET */
2436
2437
2438   /* symbolic operators for numeric and string comparison, and a number of
2439   other operators, all requiring two arguments.
2440
2441   crypteq:           encrypts plaintext and compares against an encrypted text,
2442                        using crypt(), crypt16(), MD5 or SHA-1
2443   inlist/inlisti:    checks if first argument is in the list of the second
2444   match:             does a regular expression match and sets up the numerical
2445                        variables if it succeeds
2446   match_address:     matches in an address list
2447   match_domain:      matches in a domain list
2448   match_ip:          matches a host list that is restricted to IP addresses
2449   match_local_part:  matches in a local part list
2450   */
2451
2452   case ECOND_MATCH_ADDRESS:
2453   case ECOND_MATCH_DOMAIN:
2454   case ECOND_MATCH_IP:
2455   case ECOND_MATCH_LOCAL_PART:
2456 #ifndef EXPAND_LISTMATCH_RHS
2457     sub2_honour_dollar = FALSE;
2458 #endif
2459     /* FALLTHROUGH */
2460
2461   case ECOND_CRYPTEQ:
2462   case ECOND_INLIST:
2463   case ECOND_INLISTI:
2464   case ECOND_MATCH:
2465
2466   case ECOND_NUM_L:     /* Numerical comparisons */
2467   case ECOND_NUM_LE:
2468   case ECOND_NUM_E:
2469   case ECOND_NUM_EE:
2470   case ECOND_NUM_G:
2471   case ECOND_NUM_GE:
2472
2473   case ECOND_STR_LT:    /* String comparisons */
2474   case ECOND_STR_LTI:
2475   case ECOND_STR_LE:
2476   case ECOND_STR_LEI:
2477   case ECOND_STR_EQ:
2478   case ECOND_STR_EQI:
2479   case ECOND_STR_GT:
2480   case ECOND_STR_GTI:
2481   case ECOND_STR_GE:
2482   case ECOND_STR_GEI:
2483
2484   for (i = 0; i < 2; i++)
2485     {
2486     /* Sometimes, we don't expand substrings; too many insecure configurations
2487     created using match_address{}{} and friends, where the second param
2488     includes information from untrustworthy sources. */
2489     BOOL honour_dollar = TRUE;
2490     if ((i > 0) && !sub2_honour_dollar)
2491       honour_dollar = FALSE;
2492
2493     while (isspace(*s)) s++;
2494     if (*s != '{')
2495       {
2496       if (i == 0) goto COND_FAILED_CURLY_START;
2497       expand_string_message = string_sprintf("missing 2nd string in {} "
2498         "after \"%s\"", name);
2499       return NULL;
2500       }
2501     sub[i] = expand_string_internal(s+1, TRUE, &s, yield == NULL,
2502         honour_dollar, resetok);
2503     if (sub[i] == NULL) return NULL;
2504     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2505
2506     /* Convert to numerical if required; we know that the names of all the
2507     conditions that compare numbers do not start with a letter. This just saves
2508     checking for them individually. */
2509
2510     if (!isalpha(name[0]) && yield != NULL)
2511       if (sub[i][0] == 0)
2512         {
2513         num[i] = 0;
2514         DEBUG(D_expand)
2515           debug_printf_indent("empty string cast to zero for numerical comparison\n");
2516         }
2517       else
2518         {
2519         num[i] = expanded_string_integer(sub[i], FALSE);
2520         if (expand_string_message != NULL) return NULL;
2521         }
2522     }
2523
2524   /* Result not required */
2525
2526   if (yield == NULL) return s;
2527
2528   /* Do an appropriate comparison */
2529
2530   switch(cond_type)
2531     {
2532     case ECOND_NUM_E:
2533     case ECOND_NUM_EE:
2534     tempcond = (num[0] == num[1]);
2535     break;
2536
2537     case ECOND_NUM_G:
2538     tempcond = (num[0] > num[1]);
2539     break;
2540
2541     case ECOND_NUM_GE:
2542     tempcond = (num[0] >= num[1]);
2543     break;
2544
2545     case ECOND_NUM_L:
2546     tempcond = (num[0] < num[1]);
2547     break;
2548
2549     case ECOND_NUM_LE:
2550     tempcond = (num[0] <= num[1]);
2551     break;
2552
2553     case ECOND_STR_LT:
2554     tempcond = (Ustrcmp(sub[0], sub[1]) < 0);
2555     break;
2556
2557     case ECOND_STR_LTI:
2558     tempcond = (strcmpic(sub[0], sub[1]) < 0);
2559     break;
2560
2561     case ECOND_STR_LE:
2562     tempcond = (Ustrcmp(sub[0], sub[1]) <= 0);
2563     break;
2564
2565     case ECOND_STR_LEI:
2566     tempcond = (strcmpic(sub[0], sub[1]) <= 0);
2567     break;
2568
2569     case ECOND_STR_EQ:
2570     tempcond = (Ustrcmp(sub[0], sub[1]) == 0);
2571     break;
2572
2573     case ECOND_STR_EQI:
2574     tempcond = (strcmpic(sub[0], sub[1]) == 0);
2575     break;
2576
2577     case ECOND_STR_GT:
2578     tempcond = (Ustrcmp(sub[0], sub[1]) > 0);
2579     break;
2580
2581     case ECOND_STR_GTI:
2582     tempcond = (strcmpic(sub[0], sub[1]) > 0);
2583     break;
2584
2585     case ECOND_STR_GE:
2586     tempcond = (Ustrcmp(sub[0], sub[1]) >= 0);
2587     break;
2588
2589     case ECOND_STR_GEI:
2590     tempcond = (strcmpic(sub[0], sub[1]) >= 0);
2591     break;
2592
2593     case ECOND_MATCH:   /* Regular expression match */
2594     re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
2595       NULL);
2596     if (re == NULL)
2597       {
2598       expand_string_message = string_sprintf("regular expression error in "
2599         "\"%s\": %s at offset %d", sub[1], rerror, roffset);
2600       return NULL;
2601       }
2602     tempcond = regex_match_and_setup(re, sub[0], 0, -1);
2603     break;
2604
2605     case ECOND_MATCH_ADDRESS:  /* Match in an address list */
2606     rc = match_address_list(sub[0], TRUE, FALSE, &(sub[1]), NULL, -1, 0, NULL);
2607     goto MATCHED_SOMETHING;
2608
2609     case ECOND_MATCH_DOMAIN:   /* Match in a domain list */
2610     rc = match_isinlist(sub[0], &(sub[1]), 0, &domainlist_anchor, NULL,
2611       MCL_DOMAIN + MCL_NOEXPAND, TRUE, NULL);
2612     goto MATCHED_SOMETHING;
2613
2614     case ECOND_MATCH_IP:       /* Match IP address in a host list */
2615     if (sub[0][0] != 0 && string_is_ip_address(sub[0], NULL) == 0)
2616       {
2617       expand_string_message = string_sprintf("\"%s\" is not an IP address",
2618         sub[0]);
2619       return NULL;
2620       }
2621     else
2622       {
2623       unsigned int *nullcache = NULL;
2624       check_host_block cb;
2625
2626       cb.host_name = US"";
2627       cb.host_address = sub[0];
2628
2629       /* If the host address starts off ::ffff: it is an IPv6 address in
2630       IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2631       addresses. */
2632
2633       cb.host_ipv4 = (Ustrncmp(cb.host_address, "::ffff:", 7) == 0)?
2634         cb.host_address + 7 : cb.host_address;
2635
2636       rc = match_check_list(
2637              &sub[1],                   /* the list */
2638              0,                         /* separator character */
2639              &hostlist_anchor,          /* anchor pointer */
2640              &nullcache,                /* cache pointer */
2641              check_host,                /* function for testing */
2642              &cb,                       /* argument for function */
2643              MCL_HOST,                  /* type of check */
2644              sub[0],                    /* text for debugging */
2645              NULL);                     /* where to pass back data */
2646       }
2647     goto MATCHED_SOMETHING;
2648
2649     case ECOND_MATCH_LOCAL_PART:
2650     rc = match_isinlist(sub[0], &(sub[1]), 0, &localpartlist_anchor, NULL,
2651       MCL_LOCALPART + MCL_NOEXPAND, TRUE, NULL);
2652     /* Fall through */
2653     /* VVVVVVVVVVVV */
2654     MATCHED_SOMETHING:
2655     switch(rc)
2656       {
2657       case OK:
2658       tempcond = TRUE;
2659       break;
2660
2661       case FAIL:
2662       tempcond = FALSE;
2663       break;
2664
2665       case DEFER:
2666       expand_string_message = string_sprintf("unable to complete match "
2667         "against \"%s\": %s", sub[1], search_error_message);
2668       return NULL;
2669       }
2670
2671     break;
2672
2673     /* Various "encrypted" comparisons. If the second string starts with
2674     "{" then an encryption type is given. Default to crypt() or crypt16()
2675     (build-time choice). */
2676     /* }-for-text-editors */
2677
2678     case ECOND_CRYPTEQ:
2679     #ifndef SUPPORT_CRYPTEQ
2680     goto COND_FAILED_NOT_COMPILED;
2681     #else
2682     if (strncmpic(sub[1], US"{md5}", 5) == 0)
2683       {
2684       int sublen = Ustrlen(sub[1]+5);
2685       md5 base;
2686       uschar digest[16];
2687
2688       md5_start(&base);
2689       md5_end(&base, sub[0], Ustrlen(sub[0]), digest);
2690
2691       /* If the length that we are comparing against is 24, the MD5 digest
2692       is expressed as a base64 string. This is the way LDAP does it. However,
2693       some other software uses a straightforward hex representation. We assume
2694       this if the length is 32. Other lengths fail. */
2695
2696       if (sublen == 24)
2697         {
2698         uschar *coded = b64encode(digest, 16);
2699         DEBUG(D_auth) debug_printf("crypteq: using MD5+B64 hashing\n"
2700           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2701         tempcond = (Ustrcmp(coded, sub[1]+5) == 0);
2702         }
2703       else if (sublen == 32)
2704         {
2705         int i;
2706         uschar coded[36];
2707         for (i = 0; i < 16; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2708         coded[32] = 0;
2709         DEBUG(D_auth) debug_printf("crypteq: using MD5+hex hashing\n"
2710           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2711         tempcond = (strcmpic(coded, sub[1]+5) == 0);
2712         }
2713       else
2714         {
2715         DEBUG(D_auth) debug_printf("crypteq: length for MD5 not 24 or 32: "
2716           "fail\n  crypted=%s\n", sub[1]+5);
2717         tempcond = FALSE;
2718         }
2719       }
2720
2721     else if (strncmpic(sub[1], US"{sha1}", 6) == 0)
2722       {
2723       int sublen = Ustrlen(sub[1]+6);
2724       hctx h;
2725       uschar digest[20];
2726
2727       sha1_start(&h);
2728       sha1_end(&h, sub[0], Ustrlen(sub[0]), digest);
2729
2730       /* If the length that we are comparing against is 28, assume the SHA1
2731       digest is expressed as a base64 string. If the length is 40, assume a
2732       straightforward hex representation. Other lengths fail. */
2733
2734       if (sublen == 28)
2735         {
2736         uschar *coded = b64encode(digest, 20);
2737         DEBUG(D_auth) debug_printf("crypteq: using SHA1+B64 hashing\n"
2738           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2739         tempcond = (Ustrcmp(coded, sub[1]+6) == 0);
2740         }
2741       else if (sublen == 40)
2742         {
2743         int i;
2744         uschar coded[44];
2745         for (i = 0; i < 20; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2746         coded[40] = 0;
2747         DEBUG(D_auth) debug_printf("crypteq: using SHA1+hex hashing\n"
2748           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2749         tempcond = (strcmpic(coded, sub[1]+6) == 0);
2750         }
2751       else
2752         {
2753         DEBUG(D_auth) debug_printf("crypteq: length for SHA-1 not 28 or 40: "
2754           "fail\n  crypted=%s\n", sub[1]+6);
2755         tempcond = FALSE;
2756         }
2757       }
2758
2759     else   /* {crypt} or {crypt16} and non-{ at start */
2760            /* }-for-text-editors */
2761       {
2762       int which = 0;
2763       uschar *coded;
2764
2765       if (strncmpic(sub[1], US"{crypt}", 7) == 0)
2766         {
2767         sub[1] += 7;
2768         which = 1;
2769         }
2770       else if (strncmpic(sub[1], US"{crypt16}", 9) == 0)
2771         {
2772         sub[1] += 9;
2773         which = 2;
2774         }
2775       else if (sub[1][0] == '{')                /* }-for-text-editors */
2776         {
2777         expand_string_message = string_sprintf("unknown encryption mechanism "
2778           "in \"%s\"", sub[1]);
2779         return NULL;
2780         }
2781
2782       switch(which)
2783         {
2784         case 0:  coded = US DEFAULT_CRYPT(CS sub[0], CS sub[1]); break;
2785         case 1:  coded = US crypt(CS sub[0], CS sub[1]); break;
2786         default: coded = US crypt16(CS sub[0], CS sub[1]); break;
2787         }
2788
2789       #define STR(s) # s
2790       #define XSTR(s) STR(s)
2791       DEBUG(D_auth) debug_printf("crypteq: using %s()\n"
2792         "  subject=%s\n  crypted=%s\n",
2793         which == 0 ? XSTR(DEFAULT_CRYPT) : which == 1 ? "crypt" : "crypt16",
2794         coded, sub[1]);
2795       #undef STR
2796       #undef XSTR
2797
2798       /* If the encrypted string contains fewer than two characters (for the
2799       salt), force failure. Otherwise we get false positives: with an empty
2800       string the yield of crypt() is an empty string! */
2801
2802       if (coded)
2803         tempcond = Ustrlen(sub[1]) < 2 ? FALSE : Ustrcmp(coded, sub[1]) == 0;
2804       else if (errno == EINVAL)
2805         tempcond = FALSE;
2806       else
2807         {
2808         expand_string_message = string_sprintf("crypt error: %s\n",
2809           US strerror(errno));
2810         return NULL;
2811         }
2812       }
2813     break;
2814     #endif  /* SUPPORT_CRYPTEQ */
2815
2816     case ECOND_INLIST:
2817     case ECOND_INLISTI:
2818       {
2819       const uschar * list = sub[1];
2820       int sep = 0;
2821       uschar *save_iterate_item = iterate_item;
2822       int (*compare)(const uschar *, const uschar *);
2823
2824       DEBUG(D_expand) debug_printf_indent("condition: %s  item: %s\n", name, sub[0]);
2825
2826       tempcond = FALSE;
2827       compare = cond_type == ECOND_INLISTI
2828         ? strcmpic : (int (*)(const uschar *, const uschar *)) strcmp;
2829
2830       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)))
2831         {
2832         DEBUG(D_expand) debug_printf_indent(" compare %s\n", iterate_item);
2833         if (compare(sub[0], iterate_item) == 0)
2834           {
2835           tempcond = TRUE;
2836           break;
2837           }
2838         }
2839       iterate_item = save_iterate_item;
2840       }
2841
2842     }   /* Switch for comparison conditions */
2843
2844   *yield = tempcond == testfor;
2845   return s;    /* End of comparison conditions */
2846
2847
2848   /* and/or: computes logical and/or of several conditions */
2849
2850   case ECOND_AND:
2851   case ECOND_OR:
2852   subcondptr = (yield == NULL)? NULL : &tempcond;
2853   combined_cond = (cond_type == ECOND_AND);
2854
2855   while (isspace(*s)) s++;
2856   if (*s++ != '{') goto COND_FAILED_CURLY_START;        /* }-for-text-editors */
2857
2858   for (;;)
2859     {
2860     while (isspace(*s)) s++;
2861     /* {-for-text-editors */
2862     if (*s == '}') break;
2863     if (*s != '{')                                      /* }-for-text-editors */
2864       {
2865       expand_string_message = string_sprintf("each subcondition "
2866         "inside an \"%s{...}\" condition must be in its own {}", name);
2867       return NULL;
2868       }
2869
2870     if (!(s = eval_condition(s+1, resetok, subcondptr)))
2871       {
2872       expand_string_message = string_sprintf("%s inside \"%s{...}\" condition",
2873         expand_string_message, name);
2874       return NULL;
2875       }
2876     while (isspace(*s)) s++;
2877
2878     /* {-for-text-editors */
2879     if (*s++ != '}')
2880       {
2881       /* {-for-text-editors */
2882       expand_string_message = string_sprintf("missing } at end of condition "
2883         "inside \"%s\" group", name);
2884       return NULL;
2885       }
2886
2887     if (yield != NULL)
2888       {
2889       if (cond_type == ECOND_AND)
2890         {
2891         combined_cond &= tempcond;
2892         if (!combined_cond) subcondptr = NULL;  /* once false, don't */
2893         }                                       /* evaluate any more */
2894       else
2895         {
2896         combined_cond |= tempcond;
2897         if (combined_cond) subcondptr = NULL;   /* once true, don't */
2898         }                                       /* evaluate any more */
2899       }
2900     }
2901
2902   if (yield != NULL) *yield = (combined_cond == testfor);
2903   return ++s;
2904
2905
2906   /* forall/forany: iterates a condition with different values */
2907
2908   case ECOND_FORALL:
2909   case ECOND_FORANY:
2910     {
2911     const uschar * list;
2912     int sep = 0;
2913     uschar *save_iterate_item = iterate_item;
2914
2915     DEBUG(D_expand) debug_printf_indent("condition: %s\n", name);
2916
2917     while (isspace(*s)) s++;
2918     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2919     sub[0] = expand_string_internal(s, TRUE, &s, (yield == NULL), TRUE, resetok);
2920     if (sub[0] == NULL) return NULL;
2921     /* {-for-text-editors */
2922     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2923
2924     while (isspace(*s)) s++;
2925     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2926
2927     sub[1] = s;
2928
2929     /* Call eval_condition once, with result discarded (as if scanning a
2930     "false" part). This allows us to find the end of the condition, because if
2931     the list it empty, we won't actually evaluate the condition for real. */
2932
2933     if (!(s = eval_condition(sub[1], resetok, NULL)))
2934       {
2935       expand_string_message = string_sprintf("%s inside \"%s\" condition",
2936         expand_string_message, name);
2937       return NULL;
2938       }
2939     while (isspace(*s)) s++;
2940
2941     /* {-for-text-editors */
2942     if (*s++ != '}')
2943       {
2944       /* {-for-text-editors */
2945       expand_string_message = string_sprintf("missing } at end of condition "
2946         "inside \"%s\"", name);
2947       return NULL;
2948       }
2949
2950     if (yield != NULL) *yield = !testfor;
2951     list = sub[0];
2952     while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
2953       {
2954       DEBUG(D_expand) debug_printf_indent("%s: $item = \"%s\"\n", name, iterate_item);
2955       if (!eval_condition(sub[1], resetok, &tempcond))
2956         {
2957         expand_string_message = string_sprintf("%s inside \"%s\" condition",
2958           expand_string_message, name);
2959         iterate_item = save_iterate_item;
2960         return NULL;
2961         }
2962       DEBUG(D_expand) debug_printf_indent("%s: condition evaluated to %s\n", name,
2963         tempcond? "true":"false");
2964
2965       if (yield != NULL) *yield = (tempcond == testfor);
2966       if (tempcond == (cond_type == ECOND_FORANY)) break;
2967       }
2968
2969     iterate_item = save_iterate_item;
2970     return s;
2971     }
2972
2973
2974   /* The bool{} expansion condition maps a string to boolean.
2975   The values supported should match those supported by the ACL condition
2976   (acl.c, ACLC_CONDITION) so that we keep to a minimum the different ideas
2977   of true/false.  Note that Router "condition" rules have a different
2978   interpretation, where general data can be used and only a few values
2979   map to FALSE.
2980   Note that readconf.c boolean matching, for boolean configuration options,
2981   only matches true/yes/false/no.
2982   The bool_lax{} condition matches the Router logic, which is much more
2983   liberal. */
2984   case ECOND_BOOL:
2985   case ECOND_BOOL_LAX:
2986     {
2987     uschar *sub_arg[1];
2988     uschar *t, *t2;
2989     uschar *ourname;
2990     size_t len;
2991     BOOL boolvalue = FALSE;
2992     while (isspace(*s)) s++;
2993     if (*s != '{') goto COND_FAILED_CURLY_START;        /* }-for-text-editors */
2994     ourname = cond_type == ECOND_BOOL_LAX ? US"bool_lax" : US"bool";
2995     switch(read_subs(sub_arg, 1, 1, &s, yield == NULL, FALSE, ourname, resetok))
2996       {
2997       case 1: expand_string_message = string_sprintf(
2998                   "too few arguments or bracketing error for %s",
2999                   ourname);
3000       /*FALLTHROUGH*/
3001       case 2:
3002       case 3: return NULL;
3003       }
3004     t = sub_arg[0];
3005     while (isspace(*t)) t++;
3006     len = Ustrlen(t);
3007     if (len)
3008       {
3009       /* trailing whitespace: seems like a good idea to ignore it too */
3010       t2 = t + len - 1;
3011       while (isspace(*t2)) t2--;
3012       if (t2 != (t + len))
3013         {
3014         *++t2 = '\0';
3015         len = t2 - t;
3016         }
3017       }
3018     DEBUG(D_expand)
3019       debug_printf_indent("considering %s: %s\n", ourname, len ? t : US"<empty>");
3020     /* logic for the lax case from expand_check_condition(), which also does
3021     expands, and the logic is both short and stable enough that there should
3022     be no maintenance burden from replicating it. */
3023     if (len == 0)
3024       boolvalue = FALSE;
3025     else if (*t == '-'
3026              ? Ustrspn(t+1, "0123456789") == len-1
3027              : Ustrspn(t,   "0123456789") == len)
3028       {
3029       boolvalue = (Uatoi(t) == 0) ? FALSE : TRUE;
3030       /* expand_check_condition only does a literal string "0" check */
3031       if ((cond_type == ECOND_BOOL_LAX) && (len > 1))
3032         boolvalue = TRUE;
3033       }
3034     else if (strcmpic(t, US"true") == 0 || strcmpic(t, US"yes") == 0)
3035       boolvalue = TRUE;
3036     else if (strcmpic(t, US"false") == 0 || strcmpic(t, US"no") == 0)
3037       boolvalue = FALSE;
3038     else if (cond_type == ECOND_BOOL_LAX)
3039       boolvalue = TRUE;
3040     else
3041       {
3042       expand_string_message = string_sprintf("unrecognised boolean "
3043        "value \"%s\"", t);
3044       return NULL;
3045       }
3046     DEBUG(D_expand) debug_printf_indent("%s: condition evaluated to %s\n", ourname,
3047         boolvalue? "true":"false");
3048     if (yield != NULL) *yield = (boolvalue == testfor);
3049     return s;
3050     }
3051
3052   /* Unknown condition */
3053
3054   default:
3055   expand_string_message = string_sprintf("unknown condition \"%s\"", name);
3056   return NULL;
3057   }   /* End switch on condition type */
3058
3059 /* Missing braces at start and end of data */
3060
3061 COND_FAILED_CURLY_START:
3062 expand_string_message = string_sprintf("missing { after \"%s\"", name);
3063 return NULL;
3064
3065 COND_FAILED_CURLY_END:
3066 expand_string_message = string_sprintf("missing } at end of \"%s\" condition",
3067   name);
3068 return NULL;
3069
3070 /* A condition requires code that is not compiled */
3071
3072 #if !defined(SUPPORT_PAM) || !defined(RADIUS_CONFIG_FILE) || \
3073     !defined(LOOKUP_LDAP) || !defined(CYRUS_PWCHECK_SOCKET) || \
3074     !defined(SUPPORT_CRYPTEQ) || !defined(CYRUS_SASLAUTHD_SOCKET)
3075 COND_FAILED_NOT_COMPILED:
3076 expand_string_message = string_sprintf("support for \"%s\" not compiled",
3077   name);
3078 return NULL;
3079 #endif
3080 }
3081
3082
3083
3084
3085 /*************************************************
3086 *          Save numerical variables              *
3087 *************************************************/
3088
3089 /* This function is called from items such as "if" that want to preserve and
3090 restore the numbered variables.
3091
3092 Arguments:
3093   save_expand_string    points to an array of pointers to set
3094   save_expand_nlength   points to an array of ints for the lengths
3095
3096 Returns:                the value of expand max to save
3097 */
3098
3099 static int
3100 save_expand_strings(uschar **save_expand_nstring, int *save_expand_nlength)
3101 {
3102 int i;
3103 for (i = 0; i <= expand_nmax; i++)
3104   {
3105   save_expand_nstring[i] = expand_nstring[i];
3106   save_expand_nlength[i] = expand_nlength[i];
3107   }
3108 return expand_nmax;
3109 }
3110
3111
3112
3113 /*************************************************
3114 *           Restore numerical variables          *
3115 *************************************************/
3116
3117 /* This function restored saved values of numerical strings.
3118
3119 Arguments:
3120   save_expand_nmax      the number of strings to restore
3121   save_expand_string    points to an array of pointers
3122   save_expand_nlength   points to an array of ints
3123
3124 Returns:                nothing
3125 */
3126
3127 static void
3128 restore_expand_strings(int save_expand_nmax, uschar **save_expand_nstring,
3129   int *save_expand_nlength)
3130 {
3131 int i;
3132 expand_nmax = save_expand_nmax;
3133 for (i = 0; i <= expand_nmax; i++)
3134   {
3135   expand_nstring[i] = save_expand_nstring[i];
3136   expand_nlength[i] = save_expand_nlength[i];
3137   }
3138 }
3139
3140
3141
3142
3143
3144 /*************************************************
3145 *            Handle yes/no substrings            *
3146 *************************************************/
3147
3148 /* This function is used by ${if}, ${lookup} and ${extract} to handle the
3149 alternative substrings that depend on whether or not the condition was true,
3150 or the lookup or extraction succeeded. The substrings always have to be
3151 expanded, to check their syntax, but "skipping" is set when the result is not
3152 needed - this avoids unnecessary nested lookups.
3153
3154 Arguments:
3155   skipping       TRUE if we were skipping when this item was reached
3156   yes            TRUE if the first string is to be used, else use the second
3157   save_lookup    a value to put back into lookup_value before the 2nd expansion
3158   sptr           points to the input string pointer
3159   yieldptr       points to the output growable-string pointer
3160   type           "lookup", "if", "extract", "run", "env", "listextract" or
3161                  "certextract" for error message
3162   resetok        if not NULL, pointer to flag - write FALSE if unsafe to reset
3163                 the store.
3164
3165 Returns:         0 OK; lookup_value has been reset to save_lookup
3166                  1 expansion failed
3167                  2 expansion failed because of bracketing error
3168 */
3169
3170 static int
3171 process_yesno(BOOL skipping, BOOL yes, uschar *save_lookup, const uschar **sptr,
3172   gstring ** yieldptr, uschar *type, BOOL *resetok)
3173 {
3174 int rc = 0;
3175 const uschar *s = *sptr;    /* Local value */
3176 uschar *sub1, *sub2;
3177 const uschar * errwhere;
3178
3179 /* If there are no following strings, we substitute the contents of $value for
3180 lookups and for extractions in the success case. For the ${if item, the string
3181 "true" is substituted. In the fail case, nothing is substituted for all three
3182 items. */
3183
3184 while (isspace(*s)) s++;
3185 if (*s == '}')
3186   {
3187   if (type[0] == 'i')
3188     {
3189     if (yes && !skipping)
3190       *yieldptr = string_catn(*yieldptr, US"true", 4);
3191     }
3192   else
3193     {
3194     if (yes && lookup_value && !skipping)
3195       *yieldptr = string_cat(*yieldptr, lookup_value);
3196     lookup_value = save_lookup;
3197     }
3198   s++;
3199   goto RETURN;
3200   }
3201
3202 /* The first following string must be braced. */
3203
3204 if (*s++ != '{')
3205   {
3206   errwhere = US"'yes' part did not start with '{'";
3207   goto FAILED_CURLY;
3208   }
3209
3210 /* Expand the first substring. Forced failures are noticed only if we actually
3211 want this string. Set skipping in the call in the fail case (this will always
3212 be the case if we were already skipping). */
3213
3214 sub1 = expand_string_internal(s, TRUE, &s, !yes, TRUE, resetok);
3215 if (sub1 == NULL && (yes || !expand_string_forcedfail)) goto FAILED;
3216 expand_string_forcedfail = FALSE;
3217 if (*s++ != '}')
3218   {
3219   errwhere = US"'yes' part did not end with '}'";
3220   goto FAILED_CURLY;
3221   }
3222
3223 /* If we want the first string, add it to the output */
3224
3225 if (yes)
3226   *yieldptr = string_cat(*yieldptr, sub1);
3227
3228 /* If this is called from a lookup/env or a (cert)extract, we want to restore
3229 $value to what it was at the start of the item, so that it has this value
3230 during the second string expansion. For the call from "if" or "run" to this
3231 function, save_lookup is set to lookup_value, so that this statement does
3232 nothing. */
3233
3234 lookup_value = save_lookup;
3235
3236 /* There now follows either another substring, or "fail", or nothing. This
3237 time, forced failures are noticed only if we want the second string. We must
3238 set skipping in the nested call if we don't want this string, or if we were
3239 already skipping. */
3240
3241 while (isspace(*s)) s++;
3242 if (*s == '{')
3243   {
3244   sub2 = expand_string_internal(s+1, TRUE, &s, yes || skipping, TRUE, resetok);
3245   if (sub2 == NULL && (!yes || !expand_string_forcedfail)) goto FAILED;
3246   expand_string_forcedfail = FALSE;
3247   if (*s++ != '}')
3248     {
3249     errwhere = US"'no' part did not start with '{'";
3250     goto FAILED_CURLY;
3251     }
3252
3253   /* If we want the second string, add it to the output */
3254
3255   if (!yes)
3256     *yieldptr = string_cat(*yieldptr, sub2);
3257   }
3258
3259 /* If there is no second string, but the word "fail" is present when the use of
3260 the second string is wanted, set a flag indicating it was a forced failure
3261 rather than a syntactic error. Swallow the terminating } in case this is nested
3262 inside another lookup or if or extract. */
3263
3264 else if (*s != '}')
3265   {
3266   uschar name[256];
3267   /* deconst cast ok here as source is s anyway */
3268   s = US read_name(name, sizeof(name), s, US"_");
3269   if (Ustrcmp(name, "fail") == 0)
3270     {
3271     if (!yes && !skipping)
3272       {
3273       while (isspace(*s)) s++;
3274       if (*s++ != '}')
3275         {
3276         errwhere = US"did not close with '}' after forcedfail";
3277         goto FAILED_CURLY;
3278         }
3279       expand_string_message =
3280         string_sprintf("\"%s\" failed and \"fail\" requested", type);
3281       expand_string_forcedfail = TRUE;
3282       goto FAILED;
3283       }
3284     }
3285   else
3286     {
3287     expand_string_message =
3288       string_sprintf("syntax error in \"%s\" item - \"fail\" expected", type);
3289     goto FAILED;
3290     }
3291   }
3292
3293 /* All we have to do now is to check on the final closing brace. */
3294
3295 while (isspace(*s)) s++;
3296 if (*s++ != '}')
3297   {
3298   errwhere = US"did not close with '}'";
3299   goto FAILED_CURLY;
3300   }
3301
3302
3303 RETURN:
3304 /* Update the input pointer value before returning */
3305 *sptr = s;
3306 return rc;
3307
3308 FAILED_CURLY:
3309   /* Get here if there is a bracketing failure */
3310   expand_string_message = string_sprintf(
3311     "curly-bracket problem in conditional yes/no parsing: %s\n"
3312     " remaining string is '%s'", errwhere, --s);
3313   rc = 2;
3314   goto RETURN;
3315
3316 FAILED:
3317   /* Get here for other failures */
3318   rc = 1;
3319   goto RETURN;
3320 }
3321
3322
3323
3324
3325 /*************************************************
3326 *    Handle MD5 or SHA-1 computation for HMAC    *
3327 *************************************************/
3328
3329 /* These are some wrapping functions that enable the HMAC code to be a bit
3330 cleaner. A good compiler will spot the tail recursion.
3331
3332 Arguments:
3333   type         HMAC_MD5 or HMAC_SHA1
3334   remaining    are as for the cryptographic hash functions
3335
3336 Returns:       nothing
3337 */
3338
3339 static void
3340 chash_start(int type, void *base)
3341 {
3342 if (type == HMAC_MD5)
3343   md5_start((md5 *)base);
3344 else
3345   sha1_start((hctx *)base);
3346 }
3347
3348 static void
3349 chash_mid(int type, void *base, uschar *string)
3350 {
3351 if (type == HMAC_MD5)
3352   md5_mid((md5 *)base, string);
3353 else
3354   sha1_mid((hctx *)base, string);
3355 }
3356
3357 static void
3358 chash_end(int type, void *base, uschar *string, int length, uschar *digest)
3359 {
3360 if (type == HMAC_MD5)
3361   md5_end((md5 *)base, string, length, digest);
3362 else
3363   sha1_end((hctx *)base, string, length, digest);
3364 }
3365
3366
3367
3368
3369
3370 /********************************************************
3371 * prvs: Get last three digits of days since Jan 1, 1970 *
3372 ********************************************************/
3373
3374 /* This is needed to implement the "prvs" BATV reverse
3375    path signing scheme
3376
3377 Argument: integer "days" offset to add or substract to
3378           or from the current number of days.
3379
3380 Returns:  pointer to string containing the last three
3381           digits of the number of days since Jan 1, 1970,
3382           modified by the offset argument, NULL if there
3383           was an error in the conversion.
3384
3385 */
3386
3387 static uschar *
3388 prvs_daystamp(int day_offset)
3389 {
3390 uschar *days = store_get(32);                /* Need at least 24 for cases */
3391 (void)string_format(days, 32, TIME_T_FMT,    /* where TIME_T_FMT is %lld */
3392   (time(NULL) + day_offset*86400)/86400);
3393 return (Ustrlen(days) >= 3) ? &days[Ustrlen(days)-3] : US"100";
3394 }
3395
3396
3397
3398 /********************************************************
3399 *   prvs: perform HMAC-SHA1 computation of prvs bits    *
3400 ********************************************************/
3401
3402 /* This is needed to implement the "prvs" BATV reverse
3403    path signing scheme
3404
3405 Arguments:
3406   address RFC2821 Address to use
3407       key The key to use (must be less than 64 characters
3408           in size)
3409   key_num Single-digit key number to use. Defaults to
3410           '0' when NULL.
3411
3412 Returns:  pointer to string containing the first three
3413           bytes of the final hash in hex format, NULL if
3414           there was an error in the process.
3415 */
3416
3417 static uschar *
3418 prvs_hmac_sha1(uschar *address, uschar *key, uschar *key_num, uschar *daystamp)
3419 {
3420 gstring * hash_source;
3421 uschar * p;
3422 int i;
3423 hctx h;
3424 uschar innerhash[20];
3425 uschar finalhash[20];
3426 uschar innerkey[64];
3427 uschar outerkey[64];
3428 uschar *finalhash_hex = store_get(40);
3429
3430 if (key_num == NULL)
3431   key_num = US"0";
3432
3433 if (Ustrlen(key) > 64)
3434   return NULL;
3435
3436 hash_source = string_catn(NULL, key_num, 1);
3437 hash_source = string_catn(hash_source, daystamp, 3);
3438 hash_source = string_cat(hash_source, address);
3439 (void) string_from_gstring(hash_source);
3440
3441 DEBUG(D_expand)
3442   debug_printf_indent("prvs: hash source is '%s'\n", hash_source->s);
3443
3444 memset(innerkey, 0x36, 64);
3445 memset(outerkey, 0x5c, 64);
3446
3447 for (i = 0; i < Ustrlen(key); i++)
3448   {
3449   innerkey[i] ^= key[i];
3450   outerkey[i] ^= key[i];
3451   }
3452
3453 chash_start(HMAC_SHA1, &h);
3454 chash_mid(HMAC_SHA1, &h, innerkey);
3455 chash_end(HMAC_SHA1, &h, hash_source->s, hash_source->ptr, innerhash);
3456
3457 chash_start(HMAC_SHA1, &h);
3458 chash_mid(HMAC_SHA1, &h, outerkey);
3459 chash_end(HMAC_SHA1, &h, innerhash, 20, finalhash);
3460
3461 p = finalhash_hex;
3462 for (i = 0; i < 3; i++)
3463   {
3464   *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
3465   *p++ = hex_digits[finalhash[i] & 0x0f];
3466   }
3467 *p = '\0';
3468
3469 return finalhash_hex;
3470 }
3471
3472
3473
3474
3475 /*************************************************
3476 *        Join a file onto the output string      *
3477 *************************************************/
3478
3479 /* This is used for readfile/readsock and after a run expansion.
3480 It joins the contents of a file onto the output string, globally replacing
3481 newlines with a given string (optionally).
3482
3483 Arguments:
3484   f            the FILE
3485   yield        pointer to the expandable string struct
3486   eol          newline replacement string, or NULL
3487
3488 Returns:       new pointer for expandable string, terminated if non-null
3489 */
3490
3491 static gstring *
3492 cat_file(FILE *f, gstring *yield, uschar *eol)
3493 {
3494 uschar buffer[1024];
3495
3496 while (Ufgets(buffer, sizeof(buffer), f))
3497   {
3498   int len = Ustrlen(buffer);
3499   if (eol && buffer[len-1] == '\n') len--;
3500   yield = string_catn(yield, buffer, len);
3501   if (eol && buffer[len])
3502     yield = string_cat(yield, eol);
3503   }
3504
3505 (void) string_from_gstring(yield);
3506 return yield;
3507 }
3508
3509
3510
3511
3512 /*************************************************
3513 *          Evaluate numeric expression           *
3514 *************************************************/
3515
3516 /* This is a set of mutually recursive functions that evaluate an arithmetic
3517 expression involving + - * / % & | ^ ~ << >> and parentheses. The only one of
3518 these functions that is called from elsewhere is eval_expr, whose interface is:
3519
3520 Arguments:
3521   sptr        pointer to the pointer to the string - gets updated
3522   decimal     TRUE if numbers are to be assumed decimal
3523   error       pointer to where to put an error message - must be NULL on input
3524   endket      TRUE if ')' must terminate - FALSE for external call
3525
3526 Returns:      on success: the value of the expression, with *error still NULL
3527               on failure: an undefined value, with *error = a message
3528 */
3529
3530 static int_eximarith_t eval_op_or(uschar **, BOOL, uschar **);
3531
3532
3533 static int_eximarith_t
3534 eval_expr(uschar **sptr, BOOL decimal, uschar **error, BOOL endket)
3535 {
3536 uschar *s = *sptr;
3537 int_eximarith_t x = eval_op_or(&s, decimal, error);
3538 if (*error == NULL)
3539   {
3540   if (endket)
3541     {
3542     if (*s != ')')
3543       *error = US"expecting closing parenthesis";
3544     else
3545       while (isspace(*(++s)));
3546     }
3547   else if (*s != 0) *error = US"expecting operator";
3548   }
3549 *sptr = s;
3550 return x;
3551 }
3552
3553
3554 static int_eximarith_t
3555 eval_number(uschar **sptr, BOOL decimal, uschar **error)
3556 {
3557 register int c;
3558 int_eximarith_t n;
3559 uschar *s = *sptr;
3560 while (isspace(*s)) s++;
3561 c = *s;
3562 if (isdigit(c))
3563   {
3564   int count;
3565   (void)sscanf(CS s, (decimal? SC_EXIM_DEC "%n" : SC_EXIM_ARITH "%n"), &n, &count);
3566   s += count;
3567   switch (tolower(*s))
3568     {
3569     default: break;
3570     case 'k': n *= 1024; s++; break;
3571     case 'm': n *= 1024*1024; s++; break;
3572     case 'g': n *= 1024*1024*1024; s++; break;
3573     }
3574   while (isspace (*s)) s++;
3575   }
3576 else if (c == '(')
3577   {
3578   s++;
3579   n = eval_expr(&s, decimal, error, 1);
3580   }
3581 else
3582   {
3583   *error = US"expecting number or opening parenthesis";
3584   n = 0;
3585   }
3586 *sptr = s;
3587 return n;
3588 }
3589
3590
3591 static int_eximarith_t
3592 eval_op_unary(uschar **sptr, BOOL decimal, uschar **error)
3593 {
3594 uschar *s = *sptr;
3595 int_eximarith_t x;
3596 while (isspace(*s)) s++;
3597 if (*s == '+' || *s == '-' || *s == '~')
3598   {
3599   int op = *s++;
3600   x = eval_op_unary(&s, decimal, error);
3601   if (op == '-') x = -x;
3602     else if (op == '~') x = ~x;
3603   }
3604 else
3605   {
3606   x = eval_number(&s, decimal, error);
3607   }
3608 *sptr = s;
3609 return x;
3610 }
3611
3612
3613 static int_eximarith_t
3614 eval_op_mult(uschar **sptr, BOOL decimal, uschar **error)
3615 {
3616 uschar *s = *sptr;
3617 int_eximarith_t x = eval_op_unary(&s, decimal, error);
3618 if (*error == NULL)
3619   {
3620   while (*s == '*' || *s == '/' || *s == '%')
3621     {
3622     int op = *s++;
3623     int_eximarith_t y = eval_op_unary(&s, decimal, error);
3624     if (*error != NULL) break;
3625     /* SIGFPE both on div/mod by zero and on INT_MIN / -1, which would give
3626      * a value of INT_MAX+1. Note that INT_MIN * -1 gives INT_MIN for me, which
3627      * is a bug somewhere in [gcc 4.2.1, FreeBSD, amd64].  In fact, -N*-M where
3628      * -N*M is INT_MIN will yield INT_MIN.
3629      * Since we don't support floating point, this is somewhat simpler.
3630      * Ideally, we'd return an error, but since we overflow for all other
3631      * arithmetic, consistency suggests otherwise, but what's the correct value
3632      * to use?  There is none.
3633      * The C standard guarantees overflow for unsigned arithmetic but signed
3634      * overflow invokes undefined behaviour; in practice, this is overflow
3635      * except for converting INT_MIN to INT_MAX+1.  We also can't guarantee
3636      * that long/longlong larger than int are available, or we could just work
3637      * with larger types.  We should consider whether to guarantee 32bit eval
3638      * and 64-bit working variables, with errors returned.  For now ...
3639      * So, the only SIGFPEs occur with a non-shrinking div/mod, thus -1; we
3640      * can just let the other invalid results occur otherwise, as they have
3641      * until now.  For this one case, we can coerce.
3642      */
3643     if (y == -1 && x == EXIM_ARITH_MIN && op != '*')
3644       {
3645       DEBUG(D_expand)
3646         debug_printf("Integer exception dodging: " PR_EXIM_ARITH "%c-1 coerced to " PR_EXIM_ARITH "\n",
3647             EXIM_ARITH_MIN, op, EXIM_ARITH_MAX);
3648       x = EXIM_ARITH_MAX;
3649       continue;
3650       }
3651     if (op == '*')
3652       x *= y;
3653     else
3654       {
3655       if (y == 0)
3656         {
3657         *error = (op == '/') ? US"divide by zero" : US"modulo by zero";
3658         x = 0;
3659         break;
3660         }
3661       if (op == '/')
3662         x /= y;
3663       else
3664         x %= y;
3665       }
3666     }
3667   }
3668 *sptr = s;
3669 return x;
3670 }
3671
3672
3673 static int_eximarith_t
3674 eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
3675 {
3676 uschar *s = *sptr;
3677 int_eximarith_t x = eval_op_mult(&s, decimal, error);
3678 if (!*error)
3679   {
3680   while (*s == '+' || *s == '-')
3681     {
3682     int op = *s++;
3683     int_eximarith_t y = eval_op_mult(&s, decimal, error);
3684     if (*error) break;
3685     if (  (x >=   EXIM_ARITH_MAX/2  && x >=   EXIM_ARITH_MAX/2)
3686        || (x <= -(EXIM_ARITH_MAX/2) && y <= -(EXIM_ARITH_MAX/2)))
3687       {                 /* over-conservative check */
3688       *error = op == '+'
3689         ? US"overflow in sum" : US"overflow in difference";
3690       break;
3691       }
3692     if (op == '+') x += y; else x -= y;
3693     }
3694   }
3695 *sptr = s;
3696 return x;
3697 }
3698
3699
3700 static int_eximarith_t
3701 eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
3702 {
3703 uschar *s = *sptr;
3704 int_eximarith_t x = eval_op_sum(&s, decimal, error);
3705 if (*error == NULL)
3706   {
3707   while ((*s == '<' || *s == '>') && s[1] == s[0])
3708     {
3709     int_eximarith_t y;
3710     int op = *s++;
3711     s++;
3712     y = eval_op_sum(&s, decimal, error);
3713     if (*error != NULL) break;
3714     if (op == '<') x <<= y; else x >>= y;
3715     }
3716   }
3717 *sptr = s;
3718 return x;
3719 }
3720
3721
3722 static int_eximarith_t
3723 eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
3724 {
3725 uschar *s = *sptr;
3726 int_eximarith_t x = eval_op_shift(&s, decimal, error);
3727 if (*error == NULL)
3728   {
3729   while (*s == '&')
3730     {
3731     int_eximarith_t y;
3732     s++;
3733     y = eval_op_shift(&s, decimal, error);
3734     if (*error != NULL) break;
3735     x &= y;
3736     }
3737   }
3738 *sptr = s;
3739 return x;
3740 }
3741
3742
3743 static int_eximarith_t
3744 eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
3745 {
3746 uschar *s = *sptr;
3747 int_eximarith_t x = eval_op_and(&s, decimal, error);
3748 if (*error == NULL)
3749   {
3750   while (*s == '^')
3751     {
3752     int_eximarith_t y;
3753     s++;
3754     y = eval_op_and(&s, decimal, error);
3755     if (*error != NULL) break;
3756     x ^= y;
3757     }
3758   }
3759 *sptr = s;
3760 return x;
3761 }
3762
3763
3764 static int_eximarith_t
3765 eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
3766 {
3767 uschar *s = *sptr;
3768 int_eximarith_t x = eval_op_xor(&s, decimal, error);
3769 if (*error == NULL)
3770   {
3771   while (*s == '|')
3772     {
3773     int_eximarith_t y;
3774     s++;
3775     y = eval_op_xor(&s, decimal, error);
3776     if (*error != NULL) break;
3777     x |= y;
3778     }
3779   }
3780 *sptr = s;
3781 return x;
3782 }
3783
3784
3785
3786 /*************************************************
3787 *                 Expand string                  *
3788 *************************************************/
3789
3790 /* Returns either an unchanged string, or the expanded string in stacking pool
3791 store. Interpreted sequences are:
3792
3793    \...                    normal escaping rules
3794    $name                   substitutes the variable
3795    ${name}                 ditto
3796    ${op:string}            operates on the expanded string value
3797    ${item{arg1}{arg2}...}  expands the args and then does the business
3798                              some literal args are not enclosed in {}
3799
3800 There are now far too many operators and item types to make it worth listing
3801 them here in detail any more.
3802
3803 We use an internal routine recursively to handle embedded substrings. The
3804 external function follows. The yield is NULL if the expansion failed, and there
3805 are two cases: if something collapsed syntactically, or if "fail" was given
3806 as the action on a lookup failure. These can be distinguished by looking at the
3807 variable expand_string_forcedfail, which is TRUE in the latter case.
3808
3809 The skipping flag is set true when expanding a substring that isn't actually
3810 going to be used (after "if" or "lookup") and it prevents lookups from
3811 happening lower down.
3812
3813 Store usage: At start, a store block of the length of the input plus 64
3814 is obtained. This is expanded as necessary by string_cat(), which might have to
3815 get a new block, or might be able to expand the original. At the end of the
3816 function we can release any store above that portion of the yield block that
3817 was actually used. In many cases this will be optimal.
3818
3819 However: if the first item in the expansion is a variable name or header name,
3820 we reset the store before processing it; if the result is in fresh store, we
3821 use that without copying. This is helpful for expanding strings like
3822 $message_headers which can get very long.
3823
3824 There's a problem if a ${dlfunc item has side-effects that cause allocation,
3825 since resetting the store at the end of the expansion will free store that was
3826 allocated by the plugin code as well as the slop after the expanded string. So
3827 we skip any resets if ${dlfunc } has been used. The same applies for ${acl }
3828 and, given the acl condition, ${if }. This is an unfortunate consequence of
3829 string expansion becoming too powerful.
3830
3831 Arguments:
3832   string         the string to be expanded
3833   ket_ends       true if expansion is to stop at }
3834   left           if not NULL, a pointer to the first character after the
3835                  expansion is placed here (typically used with ket_ends)
3836   skipping       TRUE for recursive calls when the value isn't actually going
3837                  to be used (to allow for optimisation)
3838   honour_dollar  TRUE if $ is to be expanded,
3839                  FALSE if it's just another character
3840   resetok_p      if not NULL, pointer to flag - write FALSE if unsafe to reset
3841                  the store.
3842
3843 Returns:         NULL if expansion fails:
3844                    expand_string_forcedfail is set TRUE if failure was forced
3845                    expand_string_message contains a textual error message
3846                  a pointer to the expanded string on success
3847 */
3848
3849 static uschar *
3850 expand_string_internal(const uschar *string, BOOL ket_ends, const uschar **left,
3851   BOOL skipping, BOOL honour_dollar, BOOL *resetok_p)
3852 {
3853 gstring * yield = string_get(Ustrlen(string) + 64);
3854 int item_type;
3855 const uschar *s = string;
3856 uschar *save_expand_nstring[EXPAND_MAXN+1];
3857 int save_expand_nlength[EXPAND_MAXN+1];
3858 BOOL resetok = TRUE;
3859
3860 expand_level++;
3861 DEBUG(D_expand)
3862   debug_printf_indent(UTF8_DOWN_RIGHT "%s: %s\n",
3863     skipping
3864     ? UTF8_HORIZ UTF8_HORIZ UTF8_HORIZ "scanning"
3865     : "considering",
3866     string);
3867
3868 expand_string_forcedfail = FALSE;
3869 expand_string_message = US"";
3870
3871 while (*s != 0)
3872   {
3873   uschar *value;
3874   uschar name[256];
3875
3876   /* \ escapes the next character, which must exist, or else
3877   the expansion fails. There's a special escape, \N, which causes
3878   copying of the subject verbatim up to the next \N. Otherwise,
3879   the escapes are the standard set. */
3880
3881   if (*s == '\\')
3882     {
3883     if (s[1] == 0)
3884       {
3885       expand_string_message = US"\\ at end of string";
3886       goto EXPAND_FAILED;
3887       }
3888
3889     if (s[1] == 'N')
3890       {
3891       const uschar * t = s + 2;
3892       for (s = t; *s != 0; s++) if (*s == '\\' && s[1] == 'N') break;
3893       yield = string_catn(yield, t, s - t);
3894       if (*s != 0) s += 2;
3895       }
3896
3897     else
3898       {
3899       uschar ch[1];
3900       ch[0] = string_interpret_escape(&s);
3901       s++;
3902       yield = string_catn(yield, ch, 1);
3903       }
3904
3905     continue;
3906     }
3907
3908   /*{*/
3909   /* Anything other than $ is just copied verbatim, unless we are
3910   looking for a terminating } character. */
3911
3912   /*{*/
3913   if (ket_ends && *s == '}') break;
3914
3915   if (*s != '$' || !honour_dollar)
3916     {
3917     yield = string_catn(yield, s++, 1);
3918     continue;
3919     }
3920
3921   /* No { after the $ - must be a plain name or a number for string
3922   match variable. There has to be a fudge for variables that are the
3923   names of header fields preceded by "$header_" because header field
3924   names can contain any printing characters except space and colon.
3925   For those that don't like typing this much, "$h_" is a synonym for
3926   "$header_". A non-existent header yields a NULL value; nothing is
3927   inserted. */  /*}*/
3928
3929