src/src/expand.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2015 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8
   9 /* Functions for handling string expansion. */
  10
  11
  12 #include "exim.h"
  13
  14 /* Recursively called function */
  15
  16 static uschar *expand_string_internal(const uschar *, BOOL, const uschar **, BOOL, BOOL, BOOL *);
  17 static int_eximarith_t expanded_string_integer(const uschar *, BOOL);
  18
  19 #ifdef STAND_ALONE
  20 #ifndef SUPPORT_CRYPTEQ
  21 #define SUPPORT_CRYPTEQ
  22 #endif
  23 #endif
  24
  25 #ifdef LOOKUP_LDAP
  26 #include "lookups/ldap.h"
  27 #endif
  28
  29 #ifdef SUPPORT_CRYPTEQ
  30 #ifdef CRYPT_H
  31 #include <crypt.h>
  32 #endif
  33 #ifndef HAVE_CRYPT16
  34 extern char* crypt16(char*, char*);
  35 #endif
  36 #endif
  37
  38 /* The handling of crypt16() is a mess. I will record below the analysis of the
  39 mess that was sent to me. We decided, however, to make changing this very low
  40 priority, because in practice people are moving away from the crypt()
  41 algorithms nowadays, so it doesn't seem worth it.
  42
  43 <quote>
  44 There is an algorithm named "crypt16" in Ultrix and Tru64.  It crypts
  45 the first 8 characters of the password using a 20-round version of crypt
  46 (standard crypt does 25 rounds).  It then crypts the next 8 characters,
  47 or an empty block if the password is less than 9 characters, using a
  48 20-round version of crypt and the same salt as was used for the first
  49 block.  Charaters after the first 16 are ignored.  It always generates
  50 a 16-byte hash, which is expressed together with the salt as a string
  51 of 24 base 64 digits.  Here are some links to peruse:
  52
  53         http://cvs.pld.org.pl/pam/pamcrypt/crypt16.c?rev=1.2
  54         http://seclists.org/bugtraq/1999/Mar/0076.html
  55
  56 There's a different algorithm named "bigcrypt" in HP-UX, Digital Unix,
  57 and OSF/1.  This is the same as the standard crypt if given a password
  58 of 8 characters or less.  If given more, it first does the same as crypt
  59 using the first 8 characters, then crypts the next 8 (the 9th to 16th)
  60 using as salt the first two base 64 digits from the first hash block.
  61 If the password is more than 16 characters then it crypts the 17th to 24th
  62 characters using as salt the first two base 64 digits from the second hash
  63 block.  And so on: I've seen references to it cutting off the password at
  64 40 characters (5 blocks), 80 (10 blocks), or 128 (16 blocks).  Some links:
  65
  66         http://cvs.pld.org.pl/pam/pamcrypt/bigcrypt.c?rev=1.2
  67         http://seclists.org/bugtraq/1999/Mar/0109.html
  68         http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R2D-
  69              TET1_html/sec.c222.html#no_id_208
  70
  71 Exim has something it calls "crypt16".  It will either use a native
  72 crypt16 or its own implementation.  A native crypt16 will presumably
  73 be the one that I called "crypt16" above.  The internal "crypt16"
  74 function, however, is a two-block-maximum implementation of what I called
  75 "bigcrypt".  The documentation matches the internal code.
  76
  77 I suspect that whoever did the "crypt16" stuff for Exim didn't realise
  78 that crypt16 and bigcrypt were different things.
  79
  80 Exim uses the LDAP-style scheme identifier "{crypt16}" to refer
  81 to whatever it is using under that name.  This unfortunately sets a
  82 precedent for using "{crypt16}" to identify two incompatible algorithms
  83 whose output can't be distinguished.  With "{crypt16}" thus rendered
  84 ambiguous, I suggest you deprecate it and invent two new identifiers
  85 for the two algorithms.
  86
  87 Both crypt16 and bigcrypt are very poor algorithms, btw.  Hashing parts
  88 of the password separately means they can be cracked separately, so
  89 the double-length hash only doubles the cracking effort instead of
  90 squaring it.  I recommend salted SHA-1 ({SSHA}), or the Blowfish-based
  91 bcrypt ({CRYPT}$2a$).
  92 </quote>
  93 */
  94
  95
  96
  97 /*************************************************
  98 *            Local statics and tables            *
  99 *************************************************/
 100
 101 /* Table of item names, and corresponding switch numbers. The names must be in
 102 alphabetical order. */
 103
 104 static uschar *item_table[] = {
 105   US"acl",
 106   US"certextract",
 107   US"dlfunc",
 108   US"env",
 109   US"extract",
 110   US"filter",
 111   US"hash",
 112   US"hmac",
 113   US"if",
 114 #ifdef SUPPORT_I18N
 115   US"imapfolder",
 116 #endif
 117   US"length",
 118   US"listextract",
 119   US"lookup",
 120   US"map",
 121   US"nhash",
 122   US"perl",
 123   US"prvs",
 124   US"prvscheck",
 125   US"readfile",
 126   US"readsocket",
 127   US"reduce",
 128   US"run",
 129   US"sg",
 130   US"sort",
 131   US"substr",
 132   US"tr" };
 133
 134 enum {
 135   EITEM_ACL,
 136   EITEM_CERTEXTRACT,
 137   EITEM_DLFUNC,
 138   EITEM_ENV,
 139   EITEM_EXTRACT,
 140   EITEM_FILTER,
 141   EITEM_HASH,
 142   EITEM_HMAC,
 143   EITEM_IF,
 144 #ifdef SUPPORT_I18N
 145   EITEM_IMAPFOLDER,
 146 #endif
 147   EITEM_LENGTH,
 148   EITEM_LISTEXTRACT,
 149   EITEM_LOOKUP,
 150   EITEM_MAP,
 151   EITEM_NHASH,
 152   EITEM_PERL,
 153   EITEM_PRVS,
 154   EITEM_PRVSCHECK,
 155   EITEM_READFILE,
 156   EITEM_READSOCK,
 157   EITEM_REDUCE,
 158   EITEM_RUN,
 159   EITEM_SG,
 160   EITEM_SORT,
 161   EITEM_SUBSTR,
 162   EITEM_TR };
 163
 164 /* Tables of operator names, and corresponding switch numbers. The names must be
 165 in alphabetical order. There are two tables, because underscore is used in some
 166 cases to introduce arguments, whereas for other it is part of the name. This is
 167 an historical mis-design. */
 168
 169 static uschar *op_table_underscore[] = {
 170   US"from_utf8",
 171   US"local_part",
 172   US"quote_local_part",
 173   US"reverse_ip",
 174   US"time_eval",
 175   US"time_interval"
 176 #ifdef SUPPORT_I18N
 177  ,US"utf8_domain_from_alabel",
 178   US"utf8_domain_to_alabel",
 179   US"utf8_localpart_from_alabel",
 180   US"utf8_localpart_to_alabel"
 181 #endif
 182   };
 183
 184 enum {
 185   EOP_FROM_UTF8,
 186   EOP_LOCAL_PART,
 187   EOP_QUOTE_LOCAL_PART,
 188   EOP_REVERSE_IP,
 189   EOP_TIME_EVAL,
 190   EOP_TIME_INTERVAL
 191 #ifdef SUPPORT_I18N
 192  ,EOP_UTF8_DOMAIN_FROM_ALABEL,
 193   EOP_UTF8_DOMAIN_TO_ALABEL,
 194   EOP_UTF8_LOCALPART_FROM_ALABEL,
 195   EOP_UTF8_LOCALPART_TO_ALABEL
 196 #endif
 197   };
 198
 199 static uschar *op_table_main[] = {
 200   US"address",
 201   US"addresses",
 202   US"base62",
 203   US"base62d",
 204   US"base64",
 205   US"base64d",
 206   US"domain",
 207   US"escape",
 208   US"eval",
 209   US"eval10",
 210   US"expand",
 211   US"h",
 212   US"hash",
 213   US"hex2b64",
 214   US"hexquote",
 215   US"ipv6denorm",
 216   US"ipv6norm",
 217   US"l",
 218   US"lc",
 219   US"length",
 220   US"listcount",
 221   US"listnamed",
 222   US"mask",
 223   US"md5",
 224   US"nh",
 225   US"nhash",
 226   US"quote",
 227   US"randint",
 228   US"rfc2047",
 229   US"rfc2047d",
 230   US"rxquote",
 231   US"s",
 232   US"sha1",
 233   US"sha256",
 234   US"stat",
 235   US"str2b64",
 236   US"strlen",
 237   US"substr",
 238   US"uc",
 239   US"utf8clean" };
 240
 241 enum {
 242   EOP_ADDRESS =  nelem(op_table_underscore),
 243   EOP_ADDRESSES,
 244   EOP_BASE62,
 245   EOP_BASE62D,
 246   EOP_BASE64,
 247   EOP_BASE64D,
 248   EOP_DOMAIN,
 249   EOP_ESCAPE,
 250   EOP_EVAL,
 251   EOP_EVAL10,
 252   EOP_EXPAND,
 253   EOP_H,
 254   EOP_HASH,
 255   EOP_HEX2B64,
 256   EOP_HEXQUOTE,
 257   EOP_IPV6DENORM,
 258   EOP_IPV6NORM,
 259   EOP_L,
 260   EOP_LC,
 261   EOP_LENGTH,
 262   EOP_LISTCOUNT,
 263   EOP_LISTNAMED,
 264   EOP_MASK,
 265   EOP_MD5,
 266   EOP_NH,
 267   EOP_NHASH,
 268   EOP_QUOTE,
 269   EOP_RANDINT,
 270   EOP_RFC2047,
 271   EOP_RFC2047D,
 272   EOP_RXQUOTE,
 273   EOP_S,
 274   EOP_SHA1,
 275   EOP_SHA256,
 276   EOP_STAT,
 277   EOP_STR2B64,
 278   EOP_STRLEN,
 279   EOP_SUBSTR,
 280   EOP_UC,
 281   EOP_UTF8CLEAN };
 282
 283
 284 /* Table of condition names, and corresponding switch numbers. The names must
 285 be in alphabetical order. */
 286
 287 static uschar *cond_table[] = {
 288   US"<",
 289   US"<=",
 290   US"=",
 291   US"==",     /* Backward compatibility */
 292   US">",
 293   US">=",
 294   US"acl",
 295   US"and",
 296   US"bool",
 297   US"bool_lax",
 298   US"crypteq",
 299   US"def",
 300   US"eq",
 301   US"eqi",
 302   US"exists",
 303   US"first_delivery",
 304   US"forall",
 305   US"forany",
 306   US"ge",
 307   US"gei",
 308   US"gt",
 309   US"gti",
 310   US"inlist",
 311   US"inlisti",
 312   US"isip",
 313   US"isip4",
 314   US"isip6",
 315   US"ldapauth",
 316   US"le",
 317   US"lei",
 318   US"lt",
 319   US"lti",
 320   US"match",
 321   US"match_address",
 322   US"match_domain",
 323   US"match_ip",
 324   US"match_local_part",
 325   US"or",
 326   US"pam",
 327   US"pwcheck",
 328   US"queue_running",
 329   US"radius",
 330   US"saslauthd"
 331 };
 332
 333 enum {
 334   ECOND_NUM_L,
 335   ECOND_NUM_LE,
 336   ECOND_NUM_E,
 337   ECOND_NUM_EE,
 338   ECOND_NUM_G,
 339   ECOND_NUM_GE,
 340   ECOND_ACL,
 341   ECOND_AND,
 342   ECOND_BOOL,
 343   ECOND_BOOL_LAX,
 344   ECOND_CRYPTEQ,
 345   ECOND_DEF,
 346   ECOND_STR_EQ,
 347   ECOND_STR_EQI,
 348   ECOND_EXISTS,
 349   ECOND_FIRST_DELIVERY,
 350   ECOND_FORALL,
 351   ECOND_FORANY,
 352   ECOND_STR_GE,
 353   ECOND_STR_GEI,
 354   ECOND_STR_GT,
 355   ECOND_STR_GTI,
 356   ECOND_INLIST,
 357   ECOND_INLISTI,
 358   ECOND_ISIP,
 359   ECOND_ISIP4,
 360   ECOND_ISIP6,
 361   ECOND_LDAPAUTH,
 362   ECOND_STR_LE,
 363   ECOND_STR_LEI,
 364   ECOND_STR_LT,
 365   ECOND_STR_LTI,
 366   ECOND_MATCH,
 367   ECOND_MATCH_ADDRESS,
 368   ECOND_MATCH_DOMAIN,
 369   ECOND_MATCH_IP,
 370   ECOND_MATCH_LOCAL_PART,
 371   ECOND_OR,
 372   ECOND_PAM,
 373   ECOND_PWCHECK,
 374   ECOND_QUEUE_RUNNING,
 375   ECOND_RADIUS,
 376   ECOND_SASLAUTHD
 377 };
 378
 379
 380 /* Types of table entry */
 381
 382 enum vtypes {
 383   vtype_int,            /* value is address of int */
 384   vtype_filter_int,     /* ditto, but recognized only when filtering */
 385   vtype_ino,            /* value is address of ino_t (not always an int) */
 386   vtype_uid,            /* value is address of uid_t (not always an int) */
 387   vtype_gid,            /* value is address of gid_t (not always an int) */
 388   vtype_bool,           /* value is address of bool */
 389   vtype_stringptr,      /* value is address of pointer to string */
 390   vtype_msgbody,        /* as stringptr, but read when first required */
 391   vtype_msgbody_end,    /* ditto, the end of the message */
 392   vtype_msgheaders,     /* the message's headers, processed */
 393   vtype_msgheaders_raw, /* the message's headers, unprocessed */
 394   vtype_localpart,      /* extract local part from string */
 395   vtype_domain,         /* extract domain from string */
 396   vtype_string_func,    /* value is string returned by given function */
 397   vtype_todbsdin,       /* value not used; generate BSD inbox tod */
 398   vtype_tode,           /* value not used; generate tod in epoch format */
 399   vtype_todel,          /* value not used; generate tod in epoch/usec format */
 400   vtype_todf,           /* value not used; generate full tod */
 401   vtype_todl,           /* value not used; generate log tod */
 402   vtype_todlf,          /* value not used; generate log file datestamp tod */
 403   vtype_todzone,        /* value not used; generate time zone only */
 404   vtype_todzulu,        /* value not used; generate zulu tod */
 405   vtype_reply,          /* value not used; get reply from headers */
 406   vtype_pid,            /* value not used; result is pid */
 407   vtype_host_lookup,    /* value not used; get host name */
 408   vtype_load_avg,       /* value not used; result is int from os_getloadavg */
 409   vtype_pspace,         /* partition space; value is T/F for spool/log */
 410   vtype_pinodes,        /* partition inodes; value is T/F for spool/log */
 411   vtype_cert            /* SSL certificate */
 412   #ifndef DISABLE_DKIM
 413   ,vtype_dkim           /* Lookup of value in DKIM signature */
 414   #endif
 415 };
 416
 417 /* Type for main variable table */
 418
 419 typedef struct {
 420   const char *name;
 421   enum vtypes type;
 422   void       *value;
 423 } var_entry;
 424
 425 /* Type for entries pointing to address/length pairs. Not currently
 426 in use. */
 427
 428 typedef struct {
 429   uschar **address;
 430   int  *length;
 431 } alblock;
 432
 433 static uschar * fn_recipients(void);
 434
 435 /* This table must be kept in alphabetical order. */
 436
 437 static var_entry var_table[] = {
 438   /* WARNING: Do not invent variables whose names start acl_c or acl_m because
 439      they will be confused with user-creatable ACL variables. */
 440   { "acl_arg1",            vtype_stringptr,   &acl_arg[0] },
 441   { "acl_arg2",            vtype_stringptr,   &acl_arg[1] },
 442   { "acl_arg3",            vtype_stringptr,   &acl_arg[2] },
 443   { "acl_arg4",            vtype_stringptr,   &acl_arg[3] },
 444   { "acl_arg5",            vtype_stringptr,   &acl_arg[4] },
 445   { "acl_arg6",            vtype_stringptr,   &acl_arg[5] },
 446   { "acl_arg7",            vtype_stringptr,   &acl_arg[6] },
 447   { "acl_arg8",            vtype_stringptr,   &acl_arg[7] },
 448   { "acl_arg9",            vtype_stringptr,   &acl_arg[8] },
 449   { "acl_narg",            vtype_int,         &acl_narg },
 450   { "acl_verify_message",  vtype_stringptr,   &acl_verify_message },
 451   { "address_data",        vtype_stringptr,   &deliver_address_data },
 452   { "address_file",        vtype_stringptr,   &address_file },
 453   { "address_pipe",        vtype_stringptr,   &address_pipe },
 454   { "authenticated_fail_id",vtype_stringptr,  &authenticated_fail_id },
 455   { "authenticated_id",    vtype_stringptr,   &authenticated_id },
 456   { "authenticated_sender",vtype_stringptr,   &authenticated_sender },
 457   { "authentication_failed",vtype_int,        &authentication_failed },
 458 #ifdef WITH_CONTENT_SCAN
 459   { "av_failed",           vtype_int,         &av_failed },
 460 #endif
 461 #ifdef EXPERIMENTAL_BRIGHTMAIL
 462   { "bmi_alt_location",    vtype_stringptr,   &bmi_alt_location },
 463   { "bmi_base64_tracker_verdict", vtype_stringptr, &bmi_base64_tracker_verdict },
 464   { "bmi_base64_verdict",  vtype_stringptr,   &bmi_base64_verdict },
 465   { "bmi_deliver",         vtype_int,         &bmi_deliver },
 466 #endif
 467   { "body_linecount",      vtype_int,         &body_linecount },
 468   { "body_zerocount",      vtype_int,         &body_zerocount },
 469   { "bounce_recipient",    vtype_stringptr,   &bounce_recipient },
 470   { "bounce_return_size_limit", vtype_int,    &bounce_return_size_limit },
 471   { "caller_gid",          vtype_gid,         &real_gid },
 472   { "caller_uid",          vtype_uid,         &real_uid },
 473   { "callout_address",     vtype_stringptr,   &callout_address },
 474   { "compile_date",        vtype_stringptr,   &version_date },
 475   { "compile_number",      vtype_stringptr,   &version_cnumber },
 476   { "config_dir",          vtype_stringptr,   &config_main_directory },
 477   { "config_file",         vtype_stringptr,   &config_main_filename },
 478   { "csa_status",          vtype_stringptr,   &csa_status },
 479 #ifdef EXPERIMENTAL_DCC
 480   { "dcc_header",          vtype_stringptr,   &dcc_header },
 481   { "dcc_result",          vtype_stringptr,   &dcc_result },
 482 #endif
 483 #ifdef WITH_OLD_DEMIME
 484   { "demime_errorlevel",   vtype_int,         &demime_errorlevel },
 485   { "demime_reason",       vtype_stringptr,   &demime_reason },
 486 #endif
 487 #ifndef DISABLE_DKIM
 488   { "dkim_algo",           vtype_dkim,        (void *)DKIM_ALGO },
 489   { "dkim_bodylength",     vtype_dkim,        (void *)DKIM_BODYLENGTH },
 490   { "dkim_canon_body",     vtype_dkim,        (void *)DKIM_CANON_BODY },
 491   { "dkim_canon_headers",  vtype_dkim,        (void *)DKIM_CANON_HEADERS },
 492   { "dkim_copiedheaders",  vtype_dkim,        (void *)DKIM_COPIEDHEADERS },
 493   { "dkim_created",        vtype_dkim,        (void *)DKIM_CREATED },
 494   { "dkim_cur_signer",     vtype_stringptr,   &dkim_cur_signer },
 495   { "dkim_domain",         vtype_stringptr,   &dkim_signing_domain },
 496   { "dkim_expires",        vtype_dkim,        (void *)DKIM_EXPIRES },
 497   { "dkim_headernames",    vtype_dkim,        (void *)DKIM_HEADERNAMES },
 498   { "dkim_identity",       vtype_dkim,        (void *)DKIM_IDENTITY },
 499   { "dkim_key_granularity",vtype_dkim,        (void *)DKIM_KEY_GRANULARITY },
 500   { "dkim_key_length",     vtype_int,         &dkim_key_length },
 501   { "dkim_key_nosubdomains",vtype_dkim,       (void *)DKIM_NOSUBDOMAINS },
 502   { "dkim_key_notes",      vtype_dkim,        (void *)DKIM_KEY_NOTES },
 503   { "dkim_key_srvtype",    vtype_dkim,        (void *)DKIM_KEY_SRVTYPE },
 504   { "dkim_key_testing",    vtype_dkim,        (void *)DKIM_KEY_TESTING },
 505   { "dkim_selector",       vtype_stringptr,   &dkim_signing_selector },
 506   { "dkim_signers",        vtype_stringptr,   &dkim_signers },
 507   { "dkim_verify_reason",  vtype_dkim,        (void *)DKIM_VERIFY_REASON },
 508   { "dkim_verify_status",  vtype_dkim,        (void *)DKIM_VERIFY_STATUS},
 509 #endif
 510 #ifdef EXPERIMENTAL_DMARC
 511   { "dmarc_ar_header",     vtype_stringptr,   &dmarc_ar_header },
 512   { "dmarc_domain_policy", vtype_stringptr,   &dmarc_domain_policy },
 513   { "dmarc_status",        vtype_stringptr,   &dmarc_status },
 514   { "dmarc_status_text",   vtype_stringptr,   &dmarc_status_text },
 515   { "dmarc_used_domain",   vtype_stringptr,   &dmarc_used_domain },
 516 #endif
 517   { "dnslist_domain",      vtype_stringptr,   &dnslist_domain },
 518   { "dnslist_matched",     vtype_stringptr,   &dnslist_matched },
 519   { "dnslist_text",        vtype_stringptr,   &dnslist_text },
 520   { "dnslist_value",       vtype_stringptr,   &dnslist_value },
 521   { "domain",              vtype_stringptr,   &deliver_domain },
 522   { "domain_data",         vtype_stringptr,   &deliver_domain_data },
 523 #ifndef DISABLE_EVENT
 524   { "event_data",          vtype_stringptr,   &event_data },
 525
 526   /*XXX want to use generic vars for as many of these as possible*/
 527   { "event_defer_errno",   vtype_int,         &event_defer_errno },
 528
 529   { "event_name",          vtype_stringptr,   &event_name },
 530 #endif
 531   { "exim_gid",            vtype_gid,         &exim_gid },
 532   { "exim_path",           vtype_stringptr,   &exim_path },
 533   { "exim_uid",            vtype_uid,         &exim_uid },
 534   { "exim_version",        vtype_stringptr,   &version_string },
 535 #ifdef WITH_OLD_DEMIME
 536   { "found_extension",     vtype_stringptr,   &found_extension },
 537 #endif
 538   { "headers_added",       vtype_string_func, &fn_hdrs_added },
 539   { "home",                vtype_stringptr,   &deliver_home },
 540   { "host",                vtype_stringptr,   &deliver_host },
 541   { "host_address",        vtype_stringptr,   &deliver_host_address },
 542   { "host_data",           vtype_stringptr,   &host_data },
 543   { "host_lookup_deferred",vtype_int,         &host_lookup_deferred },
 544   { "host_lookup_failed",  vtype_int,         &host_lookup_failed },
 545   { "host_port",           vtype_int,         &deliver_host_port },
 546   { "initial_cwd",         vtype_stringptr,   &initial_cwd },
 547   { "inode",               vtype_ino,         &deliver_inode },
 548   { "interface_address",   vtype_stringptr,   &interface_address },
 549   { "interface_port",      vtype_int,         &interface_port },
 550   { "item",                vtype_stringptr,   &iterate_item },
 551   #ifdef LOOKUP_LDAP
 552   { "ldap_dn",             vtype_stringptr,   &eldap_dn },
 553   #endif
 554   { "load_average",        vtype_load_avg,    NULL },
 555   { "local_part",          vtype_stringptr,   &deliver_localpart },
 556   { "local_part_data",     vtype_stringptr,   &deliver_localpart_data },
 557   { "local_part_prefix",   vtype_stringptr,   &deliver_localpart_prefix },
 558   { "local_part_suffix",   vtype_stringptr,   &deliver_localpart_suffix },
 559   { "local_scan_data",     vtype_stringptr,   &local_scan_data },
 560   { "local_user_gid",      vtype_gid,         &local_user_gid },
 561   { "local_user_uid",      vtype_uid,         &local_user_uid },
 562   { "localhost_number",    vtype_int,         &host_number },
 563   { "log_inodes",          vtype_pinodes,     (void *)FALSE },
 564   { "log_space",           vtype_pspace,      (void *)FALSE },
 565   { "lookup_dnssec_authenticated",vtype_stringptr,&lookup_dnssec_authenticated},
 566   { "mailstore_basename",  vtype_stringptr,   &mailstore_basename },
 567 #ifdef WITH_CONTENT_SCAN
 568   { "malware_name",        vtype_stringptr,   &malware_name },
 569 #endif
 570   { "max_received_linelength", vtype_int,     &max_received_linelength },
 571   { "message_age",         vtype_int,         &message_age },
 572   { "message_body",        vtype_msgbody,     &message_body },
 573   { "message_body_end",    vtype_msgbody_end, &message_body_end },
 574   { "message_body_size",   vtype_int,         &message_body_size },
 575   { "message_exim_id",     vtype_stringptr,   &message_id },
 576   { "message_headers",     vtype_msgheaders,  NULL },
 577   { "message_headers_raw", vtype_msgheaders_raw, NULL },
 578   { "message_id",          vtype_stringptr,   &message_id },
 579   { "message_linecount",   vtype_int,         &message_linecount },
 580   { "message_size",        vtype_int,         &message_size },
 581 #ifdef SUPPORT_I18N
 582   { "message_smtputf8",    vtype_bool,        &message_smtputf8 },
 583 #endif
 584 #ifdef WITH_CONTENT_SCAN
 585   { "mime_anomaly_level",  vtype_int,         &mime_anomaly_level },
 586   { "mime_anomaly_text",   vtype_stringptr,   &mime_anomaly_text },
 587   { "mime_boundary",       vtype_stringptr,   &mime_boundary },
 588   { "mime_charset",        vtype_stringptr,   &mime_charset },
 589   { "mime_content_description", vtype_stringptr, &mime_content_description },
 590   { "mime_content_disposition", vtype_stringptr, &mime_content_disposition },
 591   { "mime_content_id",     vtype_stringptr,   &mime_content_id },
 592   { "mime_content_size",   vtype_int,         &mime_content_size },
 593   { "mime_content_transfer_encoding",vtype_stringptr, &mime_content_transfer_encoding },
 594   { "mime_content_type",   vtype_stringptr,   &mime_content_type },
 595   { "mime_decoded_filename", vtype_stringptr, &mime_decoded_filename },
 596   { "mime_filename",       vtype_stringptr,   &mime_filename },
 597   { "mime_is_coverletter", vtype_int,         &mime_is_coverletter },
 598   { "mime_is_multipart",   vtype_int,         &mime_is_multipart },
 599   { "mime_is_rfc822",      vtype_int,         &mime_is_rfc822 },
 600   { "mime_part_count",     vtype_int,         &mime_part_count },
 601 #endif
 602   { "n0",                  vtype_filter_int,  &filter_n[0] },
 603   { "n1",                  vtype_filter_int,  &filter_n[1] },
 604   { "n2",                  vtype_filter_int,  &filter_n[2] },
 605   { "n3",                  vtype_filter_int,  &filter_n[3] },
 606   { "n4",                  vtype_filter_int,  &filter_n[4] },
 607   { "n5",                  vtype_filter_int,  &filter_n[5] },
 608   { "n6",                  vtype_filter_int,  &filter_n[6] },
 609   { "n7",                  vtype_filter_int,  &filter_n[7] },
 610   { "n8",                  vtype_filter_int,  &filter_n[8] },
 611   { "n9",                  vtype_filter_int,  &filter_n[9] },
 612   { "original_domain",     vtype_stringptr,   &deliver_domain_orig },
 613   { "original_local_part", vtype_stringptr,   &deliver_localpart_orig },
 614   { "originator_gid",      vtype_gid,         &originator_gid },
 615   { "originator_uid",      vtype_uid,         &originator_uid },
 616   { "parent_domain",       vtype_stringptr,   &deliver_domain_parent },
 617   { "parent_local_part",   vtype_stringptr,   &deliver_localpart_parent },
 618   { "pid",                 vtype_pid,         NULL },
 619 #ifndef DISABLE_PRDR
 620   { "prdr_requested",      vtype_bool,        &prdr_requested },
 621 #endif
 622   { "primary_hostname",    vtype_stringptr,   &primary_hostname },
 623 #if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS)
 624   { "proxy_external_address",vtype_stringptr, &proxy_external_address },
 625   { "proxy_external_port", vtype_int,         &proxy_external_port },
 626   { "proxy_local_address", vtype_stringptr,   &proxy_local_address },
 627   { "proxy_local_port",    vtype_int,         &proxy_local_port },
 628   { "proxy_session",       vtype_bool,        &proxy_session },
 629 #endif
 630   { "prvscheck_address",   vtype_stringptr,   &prvscheck_address },
 631   { "prvscheck_keynum",    vtype_stringptr,   &prvscheck_keynum },
 632   { "prvscheck_result",    vtype_stringptr,   &prvscheck_result },
 633   { "qualify_domain",      vtype_stringptr,   &qualify_domain_sender },
 634   { "qualify_recipient",   vtype_stringptr,   &qualify_domain_recipient },
 635   { "rcpt_count",          vtype_int,         &rcpt_count },
 636   { "rcpt_defer_count",    vtype_int,         &rcpt_defer_count },
 637   { "rcpt_fail_count",     vtype_int,         &rcpt_fail_count },
 638   { "received_count",      vtype_int,         &received_count },
 639   { "received_for",        vtype_stringptr,   &received_for },
 640   { "received_ip_address", vtype_stringptr,   &interface_address },
 641   { "received_port",       vtype_int,         &interface_port },
 642   { "received_protocol",   vtype_stringptr,   &received_protocol },
 643   { "received_time",       vtype_int,         &received_time },
 644   { "recipient_data",      vtype_stringptr,   &recipient_data },
 645   { "recipient_verify_failure",vtype_stringptr,&recipient_verify_failure },
 646   { "recipients",          vtype_string_func, &fn_recipients },
 647   { "recipients_count",    vtype_int,         &recipients_count },
 648 #ifdef WITH_CONTENT_SCAN
 649   { "regex_match_string",  vtype_stringptr,   &regex_match_string },
 650 #endif
 651   { "reply_address",       vtype_reply,       NULL },
 652   { "return_path",         vtype_stringptr,   &return_path },
 653   { "return_size_limit",   vtype_int,         &bounce_return_size_limit },
 654   { "router_name",         vtype_stringptr,   &router_name },
 655   { "runrc",               vtype_int,         &runrc },
 656   { "self_hostname",       vtype_stringptr,   &self_hostname },
 657   { "sender_address",      vtype_stringptr,   &sender_address },
 658   { "sender_address_data", vtype_stringptr,   &sender_address_data },
 659   { "sender_address_domain", vtype_domain,    &sender_address },
 660   { "sender_address_local_part", vtype_localpart, &sender_address },
 661   { "sender_data",         vtype_stringptr,   &sender_data },
 662   { "sender_fullhost",     vtype_stringptr,   &sender_fullhost },
 663   { "sender_helo_dnssec",  vtype_bool,        &sender_helo_dnssec },
 664   { "sender_helo_name",    vtype_stringptr,   &sender_helo_name },
 665   { "sender_host_address", vtype_stringptr,   &sender_host_address },
 666   { "sender_host_authenticated",vtype_stringptr, &sender_host_authenticated },
 667   { "sender_host_dnssec",  vtype_bool,        &sender_host_dnssec },
 668   { "sender_host_name",    vtype_host_lookup, NULL },
 669   { "sender_host_port",    vtype_int,         &sender_host_port },
 670   { "sender_ident",        vtype_stringptr,   &sender_ident },
 671   { "sender_rate",         vtype_stringptr,   &sender_rate },
 672   { "sender_rate_limit",   vtype_stringptr,   &sender_rate_limit },
 673   { "sender_rate_period",  vtype_stringptr,   &sender_rate_period },
 674   { "sender_rcvhost",      vtype_stringptr,   &sender_rcvhost },
 675   { "sender_verify_failure",vtype_stringptr,  &sender_verify_failure },
 676   { "sending_ip_address",  vtype_stringptr,   &sending_ip_address },
 677   { "sending_port",        vtype_int,         &sending_port },
 678   { "smtp_active_hostname", vtype_stringptr,  &smtp_active_hostname },
 679   { "smtp_command",        vtype_stringptr,   &smtp_cmd_buffer },
 680   { "smtp_command_argument", vtype_stringptr, &smtp_cmd_argument },
 681   { "smtp_count_at_connection_start", vtype_int, &smtp_accept_count },
 682   { "smtp_notquit_reason", vtype_stringptr,   &smtp_notquit_reason },
 683   { "sn0",                 vtype_filter_int,  &filter_sn[0] },
 684   { "sn1",                 vtype_filter_int,  &filter_sn[1] },
 685   { "sn2",                 vtype_filter_int,  &filter_sn[2] },
 686   { "sn3",                 vtype_filter_int,  &filter_sn[3] },
 687   { "sn4",                 vtype_filter_int,  &filter_sn[4] },
 688   { "sn5",                 vtype_filter_int,  &filter_sn[5] },
 689   { "sn6",                 vtype_filter_int,  &filter_sn[6] },
 690   { "sn7",                 vtype_filter_int,  &filter_sn[7] },
 691   { "sn8",                 vtype_filter_int,  &filter_sn[8] },
 692   { "sn9",                 vtype_filter_int,  &filter_sn[9] },
 693 #ifdef WITH_CONTENT_SCAN
 694   { "spam_action",         vtype_stringptr,   &spam_action },
 695   { "spam_bar",            vtype_stringptr,   &spam_bar },
 696   { "spam_report",         vtype_stringptr,   &spam_report },
 697   { "spam_score",          vtype_stringptr,   &spam_score },
 698   { "spam_score_int",      vtype_stringptr,   &spam_score_int },
 699 #endif
 700 #ifdef EXPERIMENTAL_SPF
 701   { "spf_guess",           vtype_stringptr,   &spf_guess },
 702   { "spf_header_comment",  vtype_stringptr,   &spf_header_comment },
 703   { "spf_received",        vtype_stringptr,   &spf_received },
 704   { "spf_result",          vtype_stringptr,   &spf_result },
 705   { "spf_smtp_comment",    vtype_stringptr,   &spf_smtp_comment },
 706 #endif
 707   { "spool_directory",     vtype_stringptr,   &spool_directory },
 708   { "spool_inodes",        vtype_pinodes,     (void *)TRUE },
 709   { "spool_space",         vtype_pspace,      (void *)TRUE },
 710 #ifdef EXPERIMENTAL_SRS
 711   { "srs_db_address",      vtype_stringptr,   &srs_db_address },
 712   { "srs_db_key",          vtype_stringptr,   &srs_db_key },
 713   { "srs_orig_recipient",  vtype_stringptr,   &srs_orig_recipient },
 714   { "srs_orig_sender",     vtype_stringptr,   &srs_orig_sender },
 715   { "srs_recipient",       vtype_stringptr,   &srs_recipient },
 716   { "srs_status",          vtype_stringptr,   &srs_status },
 717 #endif
 718   { "thisaddress",         vtype_stringptr,   &filter_thisaddress },
 719
 720   /* The non-(in,out) variables are now deprecated */
 721   { "tls_bits",            vtype_int,         &tls_in.bits },
 722   { "tls_certificate_verified", vtype_int,    &tls_in.certificate_verified },
 723   { "tls_cipher",          vtype_stringptr,   &tls_in.cipher },
 724
 725   { "tls_in_bits",         vtype_int,         &tls_in.bits },
 726   { "tls_in_certificate_verified", vtype_int, &tls_in.certificate_verified },
 727   { "tls_in_cipher",       vtype_stringptr,   &tls_in.cipher },
 728   { "tls_in_ocsp",         vtype_int,         &tls_in.ocsp },
 729   { "tls_in_ourcert",      vtype_cert,        &tls_in.ourcert },
 730   { "tls_in_peercert",     vtype_cert,        &tls_in.peercert },
 731   { "tls_in_peerdn",       vtype_stringptr,   &tls_in.peerdn },
 732 #if defined(SUPPORT_TLS)
 733   { "tls_in_sni",          vtype_stringptr,   &tls_in.sni },
 734 #endif
 735   { "tls_out_bits",        vtype_int,         &tls_out.bits },
 736   { "tls_out_certificate_verified", vtype_int,&tls_out.certificate_verified },
 737   { "tls_out_cipher",      vtype_stringptr,   &tls_out.cipher },
 738 #ifdef EXPERIMENTAL_DANE
 739   { "tls_out_dane",        vtype_bool,        &tls_out.dane_verified },
 740 #endif
 741   { "tls_out_ocsp",        vtype_int,         &tls_out.ocsp },
 742   { "tls_out_ourcert",     vtype_cert,        &tls_out.ourcert },
 743   { "tls_out_peercert",    vtype_cert,        &tls_out.peercert },
 744   { "tls_out_peerdn",      vtype_stringptr,   &tls_out.peerdn },
 745 #if defined(SUPPORT_TLS)
 746   { "tls_out_sni",         vtype_stringptr,   &tls_out.sni },
 747 #endif
 748 #ifdef EXPERIMENTAL_DANE
 749   { "tls_out_tlsa_usage",  vtype_int,         &tls_out.tlsa_usage },
 750 #endif
 751
 752   { "tls_peerdn",          vtype_stringptr,   &tls_in.peerdn }, /* mind the alphabetical order! */
 753 #if defined(SUPPORT_TLS)
 754   { "tls_sni",             vtype_stringptr,   &tls_in.sni },    /* mind the alphabetical order! */
 755 #endif
 756
 757   { "tod_bsdinbox",        vtype_todbsdin,    NULL },
 758   { "tod_epoch",           vtype_tode,        NULL },
 759   { "tod_epoch_l",         vtype_todel,       NULL },
 760   { "tod_full",            vtype_todf,        NULL },
 761   { "tod_log",             vtype_todl,        NULL },
 762   { "tod_logfile",         vtype_todlf,       NULL },
 763   { "tod_zone",            vtype_todzone,     NULL },
 764   { "tod_zulu",            vtype_todzulu,     NULL },
 765   { "transport_name",      vtype_stringptr,   &transport_name },
 766   { "value",               vtype_stringptr,   &lookup_value },
 767   { "verify_mode",         vtype_stringptr,   &verify_mode },
 768   { "version_number",      vtype_stringptr,   &version_string },
 769   { "warn_message_delay",  vtype_stringptr,   &warnmsg_delay },
 770   { "warn_message_recipient",vtype_stringptr, &warnmsg_recipients },
 771   { "warn_message_recipients",vtype_stringptr,&warnmsg_recipients },
 772   { "warnmsg_delay",       vtype_stringptr,   &warnmsg_delay },
 773   { "warnmsg_recipient",   vtype_stringptr,   &warnmsg_recipients },
 774   { "warnmsg_recipients",  vtype_stringptr,   &warnmsg_recipients }
 775 };
 776
 777 static int var_table_size = nelem(var_table);
 778 static uschar var_buffer[256];
 779 static BOOL malformed_header;
 780
 781 /* For textual hashes */
 782
 783 static const char *hashcodes = "abcdefghijklmnopqrtsuvwxyz"
 784                                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 785                                "0123456789";
 786
 787 enum { HMAC_MD5, HMAC_SHA1 };
 788
 789 /* For numeric hashes */
 790
 791 static unsigned int prime[] = {
 792   2,   3,   5,   7,  11,  13,  17,  19,  23,  29,
 793  31,  37,  41,  43,  47,  53,  59,  61,  67,  71,
 794  73,  79,  83,  89,  97, 101, 103, 107, 109, 113};
 795
 796 /* For printing modes in symbolic form */
 797
 798 static uschar *mtable_normal[] =
 799   { US"---", US"--x", US"-w-", US"-wx", US"r--", US"r-x", US"rw-", US"rwx" };
 800
 801 static uschar *mtable_setid[] =
 802   { US"--S", US"--s", US"-wS", US"-ws", US"r-S", US"r-s", US"rwS", US"rws" };
 803
 804 static uschar *mtable_sticky[] =
 805   { US"--T", US"--t", US"-wT", US"-wt", US"r-T", US"r-t", US"rwT", US"rwt" };
 806
 807
 808
 809 /*************************************************
 810 *           Tables for UTF-8 support             *
 811 *************************************************/
 812
 813 /* Table of the number of extra characters, indexed by the first character
 814 masked with 0x3f. The highest number for a valid UTF-8 character is in fact
 815 0x3d. */
 816
 817 static uschar utf8_table1[] = {
 818   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 819   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 820   2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
 821   3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5 };
 822
 823 /* These are the masks for the data bits in the first byte of a character,
 824 indexed by the number of additional bytes. */
 825
 826 static int utf8_table2[] = { 0xff, 0x1f, 0x0f, 0x07, 0x03, 0x01};
 827
 828 /* Get the next UTF-8 character, advancing the pointer. */
 829
 830 #define GETUTF8INC(c, ptr) \
 831   c = *ptr++; \
 832   if ((c & 0xc0) == 0xc0) \
 833     { \
 834     int a = utf8_table1[c & 0x3f];  /* Number of additional bytes */ \
 835     int s = 6*a; \
 836     c = (c & utf8_table2[a]) << s; \
 837     while (a-- > 0) \
 838       { \
 839       s -= 6; \
 840       c |= (*ptr++ & 0x3f) << s; \
 841       } \
 842     }
 843
 844
 845 /*************************************************
 846 *           Binary chop search on a table        *
 847 *************************************************/
 848
 849 /* This is used for matching expansion items and operators.
 850
 851 Arguments:
 852   name        the name that is being sought
 853   table       the table to search
 854   table_size  the number of items in the table
 855
 856 Returns:      the offset in the table, or -1
 857 */
 858
 859 static int
 860 chop_match(uschar *name, uschar **table, int table_size)
 861 {
 862 uschar **bot = table;
 863 uschar **top = table + table_size;
 864
 865 while (top > bot)
 866   {
 867   uschar **mid = bot + (top - bot)/2;
 868   int c = Ustrcmp(name, *mid);
 869   if (c == 0) return mid - table;
 870   if (c > 0) bot = mid + 1; else top = mid;
 871   }
 872
 873 return -1;
 874 }
 875
 876
 877
 878 /*************************************************
 879 *          Check a condition string              *
 880 *************************************************/
 881
 882 /* This function is called to expand a string, and test the result for a "true"
 883 or "false" value. Failure of the expansion yields FALSE; logged unless it was a
 884 forced fail or lookup defer.
 885
 886 We used to release all store used, but this is not not safe due
 887 to ${dlfunc } and ${acl }.  In any case expand_string_internal()
 888 is reasonably careful to release what it can.
 889
 890 The actual false-value tests should be replicated for ECOND_BOOL_LAX.
 891
 892 Arguments:
 893   condition     the condition string
 894   m1            text to be incorporated in panic error
 895   m2            ditto
 896
 897 Returns:        TRUE if condition is met, FALSE if not
 898 */
 899
 900 BOOL
 901 expand_check_condition(uschar *condition, uschar *m1, uschar *m2)
 902 {
 903 int rc;
 904 uschar *ss = expand_string(condition);
 905 if (ss == NULL)
 906   {
 907   if (!expand_string_forcedfail && !search_find_defer)
 908     log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand condition \"%s\" "
 909       "for %s %s: %s", condition, m1, m2, expand_string_message);
 910   return FALSE;
 911   }
 912 rc = ss[0] != 0 && Ustrcmp(ss, "0") != 0 && strcmpic(ss, US"no") != 0 &&
 913   strcmpic(ss, US"false") != 0;
 914 return rc;
 915 }
 916
 917
 918
 919
 920 /*************************************************
 921 *        Pseudo-random number generation         *
 922 *************************************************/
 923
 924 /* Pseudo-random number generation.  The result is not "expected" to be
 925 cryptographically strong but not so weak that someone will shoot themselves
 926 in the foot using it as a nonce in some email header scheme or whatever
 927 weirdness they'll twist this into.  The result should ideally handle fork().
 928
 929 However, if we're stuck unable to provide this, then we'll fall back to
 930 appallingly bad randomness.
 931
 932 If SUPPORT_TLS is defined then this will not be used except as an emergency
 933 fallback.
 934
 935 Arguments:
 936   max       range maximum
 937 Returns     a random number in range [0, max-1]
 938 */
 939
 940 #ifdef SUPPORT_TLS
 941 # define vaguely_random_number vaguely_random_number_fallback
 942 #endif
 943 int
 944 vaguely_random_number(int max)
 945 {
 946 #ifdef SUPPORT_TLS
 947 # undef vaguely_random_number
 948 #endif
 949   static pid_t pid = 0;
 950   pid_t p2;
 951 #if defined(HAVE_SRANDOM) && !defined(HAVE_SRANDOMDEV)
 952   struct timeval tv;
 953 #endif
 954
 955   p2 = getpid();
 956   if (p2 != pid)
 957     {
 958     if (pid != 0)
 959       {
 960
 961 #ifdef HAVE_ARC4RANDOM
 962       /* cryptographically strong randomness, common on *BSD platforms, not
 963       so much elsewhere.  Alas. */
 964 #ifndef NOT_HAVE_ARC4RANDOM_STIR
 965       arc4random_stir();
 966 #endif
 967 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 968 #ifdef HAVE_SRANDOMDEV
 969       /* uses random(4) for seeding */
 970       srandomdev();
 971 #else
 972       gettimeofday(&tv, NULL);
 973       srandom(tv.tv_sec | tv.tv_usec | getpid());
 974 #endif
 975 #else
 976       /* Poor randomness and no seeding here */
 977 #endif
 978
 979       }
 980     pid = p2;
 981     }
 982
 983 #ifdef HAVE_ARC4RANDOM
 984   return arc4random() % max;
 985 #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
 986   return random() % max;
 987 #else
 988   /* This one returns a 16-bit number, definitely not crypto-strong */
 989   return random_number(max);
 990 #endif
 991 }
 992
 993
 994
 995
 996 /*************************************************
 997 *             Pick out a name from a string      *
 998 *************************************************/
 999
1000 /* If the name is too long, it is silently truncated.
1001
1002 Arguments:
1003   name      points to a buffer into which to put the name
1004   max       is the length of the buffer
1005   s         points to the first alphabetic character of the name
1006   extras    chars other than alphanumerics to permit
1007
1008 Returns:    pointer to the first character after the name
1009
1010 Note: The test for *s != 0 in the while loop is necessary because
1011 Ustrchr() yields non-NULL if the character is zero (which is not something
1012 I expected). */
1013
1014 static const uschar *
1015 read_name(uschar *name, int max, const uschar *s, uschar *extras)
1016 {
1017 int ptr = 0;
1018 while (*s != 0 && (isalnum(*s) || Ustrchr(extras, *s) != NULL))
1019   {
1020   if (ptr < max-1) name[ptr++] = *s;
1021   s++;
1022   }
1023 name[ptr] = 0;
1024 return s;
1025 }
1026
1027
1028
1029 /*************************************************
1030 *     Pick out the rest of a header name         *
1031 *************************************************/
1032
1033 /* A variable name starting $header_ (or just $h_ for those who like
1034 abbreviations) might not be the complete header name because headers can
1035 contain any printing characters in their names, except ':'. This function is
1036 called to read the rest of the name, chop h[eader]_ off the front, and put ':'
1037 on the end, if the name was terminated by white space.
1038
1039 Arguments:
1040   name      points to a buffer in which the name read so far exists
1041   max       is the length of the buffer
1042   s         points to the first character after the name so far, i.e. the
1043             first non-alphameric character after $header_xxxxx
1044
1045 Returns:    a pointer to the first character after the header name
1046 */
1047
1048 static const uschar *
1049 read_header_name(uschar *name, int max, const uschar *s)
1050 {
1051 int prelen = Ustrchr(name, '_') - name + 1;
1052 int ptr = Ustrlen(name) - prelen;
1053 if (ptr > 0) memmove(name, name+prelen, ptr);
1054 while (mac_isgraph(*s) && *s != ':')
1055   {
1056   if (ptr < max-1) name[ptr++] = *s;
1057   s++;
1058   }
1059 if (*s == ':') s++;
1060 name[ptr++] = ':';
1061 name[ptr] = 0;
1062 return s;
1063 }
1064
1065
1066
1067 /*************************************************
1068 *           Pick out a number from a string      *
1069 *************************************************/
1070
1071 /* Arguments:
1072   n     points to an integer into which to put the number
1073   s     points to the first digit of the number
1074
1075 Returns:  a pointer to the character after the last digit
1076 */
1077 /*XXX consider expanding to int_eximarith_t.  But the test for
1078 "overbig numbers" in 0002 still needs to overflow it. */
1079
1080 static uschar *
1081 read_number(int *n, uschar *s)
1082 {
1083 *n = 0;
1084 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
1085 return s;
1086 }
1087
1088 static const uschar *
1089 read_cnumber(int *n, const uschar *s)
1090 {
1091 *n = 0;
1092 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
1093 return s;
1094 }
1095
1096
1097
1098 /*************************************************
1099 *        Extract keyed subfield from a string    *
1100 *************************************************/
1101
1102 /* The yield is in dynamic store; NULL means that the key was not found.
1103
1104 Arguments:
1105   key       points to the name of the key
1106   s         points to the string from which to extract the subfield
1107
1108 Returns:    NULL if the subfield was not found, or
1109             a pointer to the subfield's data
1110 */
1111
1112 static uschar *
1113 expand_getkeyed(uschar *key, const uschar *s)
1114 {
1115 int length = Ustrlen(key);
1116 while (isspace(*s)) s++;
1117
1118 /* Loop to search for the key */
1119
1120 while (*s != 0)
1121   {
1122   int dkeylength;
1123   uschar *data;
1124   const uschar *dkey = s;
1125
1126   while (*s != 0 && *s != '=' && !isspace(*s)) s++;
1127   dkeylength = s - dkey;
1128   while (isspace(*s)) s++;
1129   if (*s == '=') while (isspace((*(++s))));
1130
1131   data = string_dequote(&s);
1132   if (length == dkeylength && strncmpic(key, dkey, length) == 0)
1133     return data;
1134
1135   while (isspace(*s)) s++;
1136   }
1137
1138 return NULL;
1139 }
1140
1141
1142
1143 static var_entry *
1144 find_var_ent(uschar * name)
1145 {
1146 int first = 0;
1147 int last = var_table_size;
1148
1149 while (last > first)
1150   {
1151   int middle = (first + last)/2;
1152   int c = Ustrcmp(name, var_table[middle].name);
1153
1154   if (c > 0) { first = middle + 1; continue; }
1155   if (c < 0) { last = middle; continue; }
1156   return &var_table[middle];
1157   }
1158 return NULL;
1159 }
1160
1161 /*************************************************
1162 *   Extract numbered subfield from string        *
1163 *************************************************/
1164
1165 /* Extracts a numbered field from a string that is divided by tokens - for
1166 example a line from /etc/passwd is divided by colon characters.  First field is
1167 numbered one.  Negative arguments count from the right. Zero returns the whole
1168 string. Returns NULL if there are insufficient tokens in the string
1169
1170 ***WARNING***
1171 Modifies final argument - this is a dynamically generated string, so that's OK.
1172
1173 Arguments:
1174   field       number of field to be extracted,
1175                 first field = 1, whole string = 0, last field = -1
1176   separators  characters that are used to break string into tokens
1177   s           points to the string from which to extract the subfield
1178
1179 Returns:      NULL if the field was not found,
1180               a pointer to the field's data inside s (modified to add 0)
1181 */
1182
1183 static uschar *
1184 expand_gettokened (int field, uschar *separators, uschar *s)
1185 {
1186 int sep = 1;
1187 int count;
1188 uschar *ss = s;
1189 uschar *fieldtext = NULL;
1190
1191 if (field == 0) return s;
1192
1193 /* Break the line up into fields in place; for field > 0 we stop when we have
1194 done the number of fields we want. For field < 0 we continue till the end of
1195 the string, counting the number of fields. */
1196
1197 count = (field > 0)? field : INT_MAX;
1198
1199 while (count-- > 0)
1200   {
1201   size_t len;
1202
1203   /* Previous field was the last one in the string. For a positive field
1204   number, this means there are not enough fields. For a negative field number,
1205   check that there are enough, and scan back to find the one that is wanted. */
1206
1207   if (sep == 0)
1208     {
1209     if (field > 0 || (-field) > (INT_MAX - count - 1)) return NULL;
1210     if ((-field) == (INT_MAX - count - 1)) return s;
1211     while (field++ < 0)
1212       {
1213       ss--;
1214       while (ss[-1] != 0) ss--;
1215       }
1216     fieldtext = ss;
1217     break;
1218     }
1219
1220   /* Previous field was not last in the string; save its start and put a
1221   zero at its end. */
1222
1223   fieldtext = ss;
1224   len = Ustrcspn(ss, separators);
1225   sep = ss[len];
1226   ss[len] = 0;
1227   ss += len + 1;
1228   }
1229
1230 return fieldtext;
1231 }
1232
1233
1234 static uschar *
1235 expand_getlistele(int field, const uschar * list)
1236 {
1237 const uschar * tlist= list;
1238 int sep= 0;
1239 uschar dummy;
1240
1241 if(field<0)
1242   {
1243   for(field++; string_nextinlist(&tlist, &sep, &dummy, 1); ) field++;
1244   sep= 0;
1245   }
1246 if(field==0) return NULL;
1247 while(--field>0 && (string_nextinlist(&list, &sep, &dummy, 1))) ;
1248 return string_nextinlist(&list, &sep, NULL, 0);
1249 }
1250
1251
1252 /* Certificate fields, by name.  Worry about by-OID later */
1253 /* Names are chosen to not have common prefixes */
1254
1255 #ifdef SUPPORT_TLS
1256 typedef struct
1257 {
1258 uschar * name;
1259 int      namelen;
1260 uschar * (*getfn)(void * cert, uschar * mod);
1261 } certfield;
1262 static certfield certfields[] =
1263 {                       /* linear search; no special order */
1264   { US"version",         7,  &tls_cert_version },
1265   { US"serial_number",   13, &tls_cert_serial_number },
1266   { US"subject",         7,  &tls_cert_subject },
1267   { US"notbefore",       9,  &tls_cert_not_before },
1268   { US"notafter",        8,  &tls_cert_not_after },
1269   { US"issuer",          6,  &tls_cert_issuer },
1270   { US"signature",       9,  &tls_cert_signature },
1271   { US"sig_algorithm",   13, &tls_cert_signature_algorithm },
1272   { US"subj_altname",    12, &tls_cert_subject_altname },
1273   { US"ocsp_uri",        8,  &tls_cert_ocsp_uri },
1274   { US"crl_uri",         7,  &tls_cert_crl_uri },
1275 };
1276
1277 static uschar *
1278 expand_getcertele(uschar * field, uschar * certvar)
1279 {
1280 var_entry * vp;
1281 certfield * cp;
1282
1283 if (!(vp = find_var_ent(certvar)))
1284   {
1285   expand_string_message =
1286     string_sprintf("no variable named \"%s\"", certvar);
1287   return NULL;          /* Unknown variable name */
1288   }
1289 /* NB this stops us passing certs around in variable.  Might
1290 want to do that in future */
1291 if (vp->type != vtype_cert)
1292   {
1293   expand_string_message =
1294     string_sprintf("\"%s\" is not a certificate", certvar);
1295   return NULL;          /* Unknown variable name */
1296   }
1297 if (!*(void **)vp->value)
1298   return NULL;
1299
1300 if (*field >= '0' && *field <= '9')
1301   return tls_cert_ext_by_oid(*(void **)vp->value, field, 0);
1302
1303 for(cp = certfields;
1304     cp < certfields + nelem(certfields);
1305     cp++)
1306   if (Ustrncmp(cp->name, field, cp->namelen) == 0)
1307     {
1308     uschar * modifier = *(field += cp->namelen) == ','
1309       ? ++field : NULL;
1310     return (*cp->getfn)( *(void **)vp->value, modifier );
1311     }
1312
1313 expand_string_message =
1314   string_sprintf("bad field selector \"%s\" for certextract", field);
1315 return NULL;
1316 }
1317 #endif  /*SUPPORT_TLS*/
1318
1319 /*************************************************
1320 *        Extract a substring from a string       *
1321 *************************************************/
1322
1323 /* Perform the ${substr or ${length expansion operations.
1324
1325 Arguments:
1326   subject     the input string
1327   value1      the offset from the start of the input string to the start of
1328                 the output string; if negative, count from the right.
1329   value2      the length of the output string, or negative (-1) for unset
1330                 if value1 is positive, unset means "all after"
1331                 if value1 is negative, unset means "all before"
1332   len         set to the length of the returned string
1333
1334 Returns:      pointer to the output string, or NULL if there is an error
1335 */
1336
1337 static uschar *
1338 extract_substr(uschar *subject, int value1, int value2, int *len)
1339 {
1340 int sublen = Ustrlen(subject);
1341
1342 if (value1 < 0)    /* count from right */
1343   {
1344   value1 += sublen;
1345
1346   /* If the position is before the start, skip to the start, and adjust the
1347   length. If the length ends up negative, the substring is null because nothing
1348   can precede. This falls out naturally when the length is unset, meaning "all
1349   to the left". */
1350
1351   if (value1 < 0)
1352     {
1353     value2 += value1;
1354     if (value2 < 0) value2 = 0;
1355     value1 = 0;
1356     }
1357
1358   /* Otherwise an unset length => characters before value1 */
1359
1360   else if (value2 < 0)
1361     {
1362     value2 = value1;
1363     value1 = 0;
1364     }
1365   }
1366
1367 /* For a non-negative offset, if the starting position is past the end of the
1368 string, the result will be the null string. Otherwise, an unset length means
1369 "rest"; just set it to the maximum - it will be cut down below if necessary. */
1370
1371 else
1372   {
1373   if (value1 > sublen)
1374     {
1375     value1 = sublen;
1376     value2 = 0;
1377     }
1378   else if (value2 < 0) value2 = sublen;
1379   }
1380
1381 /* Cut the length down to the maximum possible for the offset value, and get
1382 the required characters. */
1383
1384 if (value1 + value2 > sublen) value2 = sublen - value1;
1385 *len = value2;
1386 return subject + value1;
1387 }
1388
1389
1390
1391
1392 /*************************************************
1393 *            Old-style hash of a string          *
1394 *************************************************/
1395
1396 /* Perform the ${hash expansion operation.
1397
1398 Arguments:
1399   subject     the input string (an expanded substring)
1400   value1      the length of the output string; if greater or equal to the
1401                 length of the input string, the input string is returned
1402   value2      the number of hash characters to use, or 26 if negative
1403   len         set to the length of the returned string
1404
1405 Returns:      pointer to the output string, or NULL if there is an error
1406 */
1407
1408 static uschar *
1409 compute_hash(uschar *subject, int value1, int value2, int *len)
1410 {
1411 int sublen = Ustrlen(subject);
1412
1413 if (value2 < 0) value2 = 26;
1414 else if (value2 > Ustrlen(hashcodes))
1415   {
1416   expand_string_message =
1417     string_sprintf("hash count \"%d\" too big", value2);
1418   return NULL;
1419   }
1420
1421 /* Calculate the hash text. We know it is shorter than the original string, so
1422 can safely place it in subject[] (we know that subject is always itself an
1423 expanded substring). */
1424
1425 if (value1 < sublen)
1426   {
1427   int c;
1428   int i = 0;
1429   int j = value1;
1430   while ((c = (subject[j])) != 0)
1431     {
1432     int shift = (c + j++) & 7;
1433     subject[i] ^= (c << shift) | (c >> (8-shift));
1434     if (++i >= value1) i = 0;
1435     }
1436   for (i = 0; i < value1; i++)
1437     subject[i] = hashcodes[(subject[i]) % value2];
1438   }
1439 else value1 = sublen;
1440
1441 *len = value1;
1442 return subject;
1443 }
1444
1445
1446
1447
1448 /*************************************************
1449 *             Numeric hash of a string           *
1450 *************************************************/
1451
1452 /* Perform the ${nhash expansion operation. The first characters of the
1453 string are treated as most important, and get the highest prime numbers.
1454
1455 Arguments:
1456   subject     the input string
1457   value1      the maximum value of the first part of the result
1458   value2      the maximum value of the second part of the result,
1459                 or negative to produce only a one-part result
1460   len         set to the length of the returned string
1461
1462 Returns:  pointer to the output string, or NULL if there is an error.
1463 */
1464
1465 static uschar *
1466 compute_nhash (uschar *subject, int value1, int value2, int *len)
1467 {
1468 uschar *s = subject;
1469 int i = 0;
1470 unsigned long int total = 0; /* no overflow */
1471
1472 while (*s != 0)
1473   {
1474   if (i == 0) i = nelem(prime) - 1;
1475   total += prime[i--] * (unsigned int)(*s++);
1476   }
1477
1478 /* If value2 is unset, just compute one number */
1479
1480 if (value2 < 0)
1481   {
1482   s = string_sprintf("%d", total % value1);
1483   }
1484
1485 /* Otherwise do a div/mod hash */
1486
1487 else
1488   {
1489   total = total % (value1 * value2);
1490   s = string_sprintf("%d/%d", total/value2, total % value2);
1491   }
1492
1493 *len = Ustrlen(s);
1494 return s;
1495 }
1496
1497
1498
1499
1500
1501 /*************************************************
1502 *     Find the value of a header or headers      *
1503 *************************************************/
1504
1505 /* Multiple instances of the same header get concatenated, and this function
1506 can also return a concatenation of all the header lines. When concatenating
1507 specific headers that contain lists of addresses, a comma is inserted between
1508 them. Otherwise we use a straight concatenation. Because some messages can have
1509 pathologically large number of lines, there is a limit on the length that is
1510 returned. Also, to avoid massive store use which would result from using
1511 string_cat() as it copies and extends strings, we do a preliminary pass to find
1512 out exactly how much store will be needed. On "normal" messages this will be
1513 pretty trivial.
1514
1515 Arguments:
1516   name          the name of the header, without the leading $header_ or $h_,
1517                 or NULL if a concatenation of all headers is required
1518   exists_only   TRUE if called from a def: test; don't need to build a string;
1519                 just return a string that is not "" and not "0" if the header
1520                 exists
1521   newsize       return the size of memory block that was obtained; may be NULL
1522                 if exists_only is TRUE
1523   want_raw      TRUE if called for $rh_ or $rheader_ variables; no processing,
1524                 other than concatenating, will be done on the header. Also used
1525                 for $message_headers_raw.
1526   charset       name of charset to translate MIME words to; used only if
1527                 want_raw is false; if NULL, no translation is done (this is
1528                 used for $bh_ and $bheader_)
1529
1530 Returns:        NULL if the header does not exist, else a pointer to a new
1531                 store block
1532 */
1533
1534 static uschar *
1535 find_header(uschar *name, BOOL exists_only, int *newsize, BOOL want_raw,
1536   uschar *charset)
1537 {
1538 BOOL found = name == NULL;
1539 int comma = 0;
1540 int len = found? 0 : Ustrlen(name);
1541 int i;
1542 uschar *yield = NULL;
1543 uschar *ptr = NULL;
1544
1545 /* Loop for two passes - saves code repetition */
1546
1547 for (i = 0; i < 2; i++)
1548   {
1549   int size = 0;
1550   header_line *h;
1551
1552   for (h = header_list; size < header_insert_maxlen && h != NULL; h = h->next)
1553     {
1554     if (h->type != htype_old && h->text != NULL)  /* NULL => Received: placeholder */
1555       {
1556       if (name == NULL || (len <= h->slen && strncmpic(name, h->text, len) == 0))
1557         {
1558         int ilen;
1559         uschar *t;
1560
1561         if (exists_only) return US"1";      /* don't need actual string */
1562         found = TRUE;
1563         t = h->text + len;                  /* text to insert */
1564         if (!want_raw)                      /* unless wanted raw, */
1565           while (isspace(*t)) t++;          /* remove leading white space */
1566         ilen = h->slen - (t - h->text);     /* length to insert */
1567
1568         /* Unless wanted raw, remove trailing whitespace, including the
1569         newline. */
1570
1571         if (!want_raw)
1572           while (ilen > 0 && isspace(t[ilen-1])) ilen--;
1573
1574         /* Set comma = 1 if handling a single header and it's one of those
1575         that contains an address list, except when asked for raw headers. Only
1576         need to do this once. */
1577
1578         if (!want_raw && name != NULL && comma == 0 &&
1579             Ustrchr("BCFRST", h->type) != NULL)
1580           comma = 1;
1581
1582         /* First pass - compute total store needed; second pass - compute
1583         total store used, including this header. */
1584
1585         size += ilen + comma + 1;  /* +1 for the newline */
1586
1587         /* Second pass - concatentate the data, up to a maximum. Note that
1588         the loop stops when size hits the limit. */
1589
1590         if (i != 0)
1591           {
1592           if (size > header_insert_maxlen)
1593             {
1594             ilen -= size - header_insert_maxlen - 1;
1595             comma = 0;
1596             }
1597           Ustrncpy(ptr, t, ilen);
1598           ptr += ilen;
1599
1600           /* For a non-raw header, put in the comma if needed, then add
1601           back the newline we removed above, provided there was some text in
1602           the header. */
1603
1604           if (!want_raw && ilen > 0)
1605             {
1606             if (comma != 0) *ptr++ = ',';
1607             *ptr++ = '\n';
1608             }
1609           }
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   {
1631   *ptr = 0;
1632   }
1633
1634 /* Otherwise, remove a final newline and a redundant added comma. Then we do
1635 RFC 2047 decoding, translating the charset if requested. The rfc2047_decode2()
1636 function can return an error with decoded data if the charset translation
1637 fails. If decoding fails, it returns NULL. */
1638
1639 else
1640   {
1641   uschar *decoded, *error;
1642   if (ptr > yield && ptr[-1] == '\n') ptr--;
1643   if (ptr > yield && comma != 0 && ptr[-1] == ',') ptr--;
1644   *ptr = 0;
1645   decoded = rfc2047_decode2(yield, check_rfc2047_length, charset, '?', NULL,
1646     newsize, &error);
1647   if (error != NULL)
1648     {
1649     DEBUG(D_any) debug_printf("*** error in RFC 2047 decoding: %s\n"
1650       "    input was: %s\n", error, yield);
1651     }
1652   if (decoded != NULL) yield = decoded;
1653   }
1654
1655 return yield;
1656 }
1657
1658
1659
1660
1661 /*************************************************
1662 *               Return list of recipients        *
1663 *************************************************/
1664 /* A recipients list is available only during system message filtering,
1665 during ACL processing after DATA, and while expanding pipe commands
1666 generated from a system filter, but not elsewhere. */
1667
1668 static uschar *
1669 fn_recipients(void)
1670 {
1671 if (!enable_dollar_recipients) return NULL; else
1672   {
1673   int size = 128;
1674   int ptr = 0;
1675   int i;
1676   uschar * s = store_get(size);
1677   for (i = 0; i < recipients_count; i++)
1678     {
1679     if (i != 0) s = string_cat(s, &size, &ptr, US", ", 2);
1680     s = string_cat(s, &size, &ptr, recipients_list[i].address,
1681       Ustrlen(recipients_list[i].address));
1682     }
1683   s[ptr] = 0;     /* string_cat() leaves room */
1684   return s;
1685   }
1686 }
1687
1688
1689 /*************************************************
1690 *               Find value of a variable         *
1691 *************************************************/
1692
1693 /* The table of variables is kept in alphabetic order, so we can search it
1694 using a binary chop. The "choplen" variable is nothing to do with the binary
1695 chop.
1696
1697 Arguments:
1698   name          the name of the variable being sought
1699   exists_only   TRUE if this is a def: test; passed on to find_header()
1700   skipping      TRUE => skip any processing evaluation; this is not the same as
1701                   exists_only because def: may test for values that are first
1702                   evaluated here
1703   newsize       pointer to an int which is initially zero; if the answer is in
1704                 a new memory buffer, *newsize is set to its size
1705
1706 Returns:        NULL if the variable does not exist, or
1707                 a pointer to the variable's contents, or
1708                 something non-NULL if exists_only is TRUE
1709 */
1710
1711 static uschar *
1712 find_variable(uschar *name, BOOL exists_only, BOOL skipping, int *newsize)
1713 {
1714 var_entry * vp;
1715 uschar *s, *domain;
1716 uschar **ss;
1717 void * val;
1718
1719 /* Handle ACL variables, whose names are of the form acl_cxxx or acl_mxxx.
1720 Originally, xxx had to be a number in the range 0-9 (later 0-19), but from
1721 release 4.64 onwards arbitrary names are permitted, as long as the first 5
1722 characters are acl_c or acl_m and the sixth is either a digit or an underscore
1723 (this gave backwards compatibility at the changeover). There may be built-in
1724 variables whose names start acl_ but they should never start in this way. This
1725 slightly messy specification is a consequence of the history, needless to say.
1726
1727 If an ACL variable does not exist, treat it as empty, unless strict_acl_vars is
1728 set, in which case give an error. */
1729
1730 if ((Ustrncmp(name, "acl_c", 5) == 0 || Ustrncmp(name, "acl_m", 5) == 0) &&
1731      !isalpha(name[5]))
1732   {
1733   tree_node *node =
1734     tree_search((name[4] == 'c')? acl_var_c : acl_var_m, name + 4);
1735   return node ? node->data.ptr : strict_acl_vars ? NULL : US"";
1736   }
1737
1738 /* Handle $auth<n> variables. */
1739
1740 if (Ustrncmp(name, "auth", 4) == 0)
1741   {
1742   uschar *endptr;
1743   int n = Ustrtoul(name + 4, &endptr, 10);
1744   if (*endptr == 0 && n != 0 && n <= AUTH_VARS)
1745     return !auth_vars[n-1] ? US"" : auth_vars[n-1];
1746   }
1747 else if (Ustrncmp(name, "regex", 5) == 0)
1748   {
1749   uschar *endptr;
1750   int n = Ustrtoul(name + 5, &endptr, 10);
1751   if (*endptr == 0 && n != 0 && n <= REGEX_VARS)
1752     return !regex_vars[n-1] ? US"" : regex_vars[n-1];
1753   }
1754
1755 /* For all other variables, search the table */
1756
1757 if (!(vp = find_var_ent(name)))
1758   return NULL;          /* Unknown variable name */
1759
1760 /* Found an existing variable. If in skipping state, the value isn't needed,
1761 and we want to avoid processing (such as looking up the host name). */
1762
1763 if (skipping)
1764   return US"";
1765
1766 val = vp->value;
1767 switch (vp->type)
1768   {
1769   case vtype_filter_int:
1770     if (!filter_running) return NULL;
1771     /* Fall through */
1772     /* VVVVVVVVVVVV */
1773   case vtype_int:
1774     sprintf(CS var_buffer, "%d", *(int *)(val)); /* Integer */
1775     return var_buffer;
1776
1777   case vtype_ino:
1778     sprintf(CS var_buffer, "%ld", (long int)(*(ino_t *)(val))); /* Inode */
1779     return var_buffer;
1780
1781   case vtype_gid:
1782     sprintf(CS var_buffer, "%ld", (long int)(*(gid_t *)(val))); /* gid */
1783     return var_buffer;
1784
1785   case vtype_uid:
1786     sprintf(CS var_buffer, "%ld", (long int)(*(uid_t *)(val))); /* uid */
1787     return var_buffer;
1788
1789   case vtype_bool:
1790     sprintf(CS var_buffer, "%s", *(BOOL *)(val) ? "yes" : "no"); /* bool */
1791     return var_buffer;
1792
1793   case vtype_stringptr:                      /* Pointer to string */
1794     return (s = *((uschar **)(val))) ? s : US"";
1795
1796   case vtype_pid:
1797     sprintf(CS var_buffer, "%d", (int)getpid()); /* pid */
1798     return var_buffer;
1799
1800   case vtype_load_avg:
1801     sprintf(CS var_buffer, "%d", OS_GETLOADAVG()); /* load_average */
1802     return var_buffer;
1803
1804   case vtype_host_lookup:                    /* Lookup if not done so */
1805     if (sender_host_name == NULL && sender_host_address != NULL &&
1806         !host_lookup_failed && host_name_lookup() == OK)
1807       host_build_sender_fullhost();
1808     return (sender_host_name == NULL)? US"" : sender_host_name;
1809
1810   case vtype_localpart:                      /* Get local part from address */
1811     s = *((uschar **)(val));
1812     if (s == NULL) return US"";
1813     domain = Ustrrchr(s, '@');
1814     if (domain == NULL) return s;
1815     if (domain - s > sizeof(var_buffer) - 1)
1816       log_write(0, LOG_MAIN|LOG_PANIC_DIE, "local part longer than " SIZE_T_FMT
1817           " in string expansion", sizeof(var_buffer));
1818     Ustrncpy(var_buffer, s, domain - s);
1819     var_buffer[domain - s] = 0;
1820     return var_buffer;
1821
1822   case vtype_domain:                         /* Get domain from address */
1823     s = *((uschar **)(val));
1824     if (s == NULL) return US"";
1825     domain = Ustrrchr(s, '@');
1826     return (domain == NULL)? US"" : domain + 1;
1827
1828   case vtype_msgheaders:
1829     return find_header(NULL, exists_only, newsize, FALSE, NULL);
1830
1831   case vtype_msgheaders_raw:
1832     return find_header(NULL, exists_only, newsize, TRUE, NULL);
1833
1834   case vtype_msgbody:                        /* Pointer to msgbody string */
1835   case vtype_msgbody_end:                    /* Ditto, the end of the msg */
1836     ss = (uschar **)(val);
1837     if (*ss == NULL && deliver_datafile >= 0)  /* Read body when needed */
1838       {
1839       uschar *body;
1840       off_t start_offset = SPOOL_DATA_START_OFFSET;
1841       int len = message_body_visible;
1842       if (len > message_size) len = message_size;
1843       *ss = body = store_malloc(len+1);
1844       body[0] = 0;
1845       if (vp->type == vtype_msgbody_end)
1846         {
1847         struct stat statbuf;
1848         if (fstat(deliver_datafile, &statbuf) == 0)
1849           {
1850           start_offset = statbuf.st_size - len;
1851           if (start_offset < SPOOL_DATA_START_OFFSET)
1852             start_offset = SPOOL_DATA_START_OFFSET;
1853           }
1854         }
1855       if (lseek(deliver_datafile, start_offset, SEEK_SET) < 0)
1856         log_write(0, LOG_MAIN|LOG_PANIC_DIE, "deliver_datafile lseek: %s",
1857           strerror(errno));
1858       len = read(deliver_datafile, body, len);
1859       if (len > 0)
1860         {
1861         body[len] = 0;
1862         if (message_body_newlines)   /* Separate loops for efficiency */
1863           while (len > 0)
1864             { if (body[--len] == 0) body[len] = ' '; }
1865         else
1866           while (len > 0)
1867             { if (body[--len] == '\n' || body[len] == 0) body[len] = ' '; }
1868         }
1869       }
1870     return (*ss == NULL)? US"" : *ss;
1871
1872   case vtype_todbsdin:                       /* BSD inbox time of day */
1873     return tod_stamp(tod_bsdin);
1874
1875   case vtype_tode:                           /* Unix epoch time of day */
1876     return tod_stamp(tod_epoch);
1877
1878   case vtype_todel:                          /* Unix epoch/usec time of day */
1879     return tod_stamp(tod_epoch_l);
1880
1881   case vtype_todf:                           /* Full time of day */
1882     return tod_stamp(tod_full);
1883
1884   case vtype_todl:                           /* Log format time of day */
1885     return tod_stamp(tod_log_bare);            /* (without timezone) */
1886
1887   case vtype_todzone:                        /* Time zone offset only */
1888     return tod_stamp(tod_zone);
1889
1890   case vtype_todzulu:                        /* Zulu time */
1891     return tod_stamp(tod_zulu);
1892
1893   case vtype_todlf:                          /* Log file datestamp tod */
1894     return tod_stamp(tod_log_datestamp_daily);
1895
1896   case vtype_reply:                          /* Get reply address */
1897     s = find_header(US"reply-to:", exists_only, newsize, TRUE,
1898       headers_charset);
1899     if (s != NULL) while (isspace(*s)) s++;
1900     if (s == NULL || *s == 0)
1901       {
1902       *newsize = 0;                            /* For the *s==0 case */
1903       s = find_header(US"from:", exists_only, newsize, TRUE, headers_charset);
1904       }
1905     if (s != NULL)
1906       {
1907       uschar *t;
1908       while (isspace(*s)) s++;
1909       for (t = s; *t != 0; t++) if (*t == '\n') *t = ' ';
1910       while (t > s && isspace(t[-1])) t--;
1911       *t = 0;
1912       }
1913     return (s == NULL)? US"" : s;
1914
1915   case vtype_string_func:
1916     {
1917     uschar * (*fn)() = val;
1918     return fn();
1919     }
1920
1921   case vtype_pspace:
1922     {
1923     int inodes;
1924     sprintf(CS var_buffer, "%d",
1925       receive_statvfs(val == (void *)TRUE, &inodes));
1926     }
1927   return var_buffer;
1928
1929   case vtype_pinodes:
1930     {
1931     int inodes;
1932     (void) receive_statvfs(val == (void *)TRUE, &inodes);
1933     sprintf(CS var_buffer, "%d", inodes);
1934     }
1935   return var_buffer;
1936
1937   case vtype_cert:
1938     return *(void **)val ? US"<cert>" : US"";
1939
1940 #ifndef DISABLE_DKIM
1941   case vtype_dkim:
1942     return dkim_exim_expand_query((int)(long)val);
1943 #endif
1944
1945   }
1946
1947 return NULL;  /* Unknown variable. Silences static checkers. */
1948 }
1949
1950
1951
1952
1953 void
1954 modify_variable(uschar *name, void * value)
1955 {
1956 var_entry * vp;
1957 if ((vp = find_var_ent(name))) vp->value = value;
1958 return;          /* Unknown variable name, fail silently */
1959 }
1960
1961
1962
1963
1964
1965 /*************************************************
1966 *           Read and expand substrings           *
1967 *************************************************/
1968
1969 /* This function is called to read and expand argument substrings for various
1970 expansion items. Some have a minimum requirement that is less than the maximum;
1971 in these cases, the first non-present one is set to NULL.
1972
1973 Arguments:
1974   sub        points to vector of pointers to set
1975   n          maximum number of substrings
1976   m          minimum required
1977   sptr       points to current string pointer
1978   skipping   the skipping flag
1979   check_end  if TRUE, check for final '}'
1980   name       name of item, for error message
1981   resetok    if not NULL, pointer to flag - write FALSE if unsafe to reset
1982              the store.
1983
1984 Returns:     0 OK; string pointer updated
1985              1 curly bracketing error (too few arguments)
1986              2 too many arguments (only if check_end is set); message set
1987              3 other error (expansion failure)
1988 */
1989
1990 static int
1991 read_subs(uschar **sub, int n, int m, const uschar **sptr, BOOL skipping,
1992   BOOL check_end, uschar *name, BOOL *resetok)
1993 {
1994 int i;
1995 const uschar *s = *sptr;
1996
1997 while (isspace(*s)) s++;
1998 for (i = 0; i < n; i++)
1999   {
2000   if (*s != '{')
2001     {
2002     if (i < m) return 1;
2003     sub[i] = NULL;
2004     break;
2005     }
2006   sub[i] = expand_string_internal(s+1, TRUE, &s, skipping, TRUE, resetok);
2007   if (sub[i] == NULL) return 3;
2008   if (*s++ != '}') return 1;
2009   while (isspace(*s)) s++;
2010   }
2011 if (check_end && *s++ != '}')
2012   {
2013   if (s[-1] == '{')
2014     {
2015     expand_string_message = string_sprintf("Too many arguments for \"%s\" "
2016       "(max is %d)", name, n);
2017     return 2;
2018     }
2019   return 1;
2020   }
2021
2022 *sptr = s;
2023 return 0;
2024 }
2025
2026
2027
2028
2029 /*************************************************
2030 *     Elaborate message for bad variable         *
2031 *************************************************/
2032
2033 /* For the "unknown variable" message, take a look at the variable's name, and
2034 give additional information about possible ACL variables. The extra information
2035 is added on to expand_string_message.
2036
2037 Argument:   the name of the variable
2038 Returns:    nothing
2039 */
2040
2041 static void
2042 check_variable_error_message(uschar *name)
2043 {
2044 if (Ustrncmp(name, "acl_", 4) == 0)
2045   expand_string_message = string_sprintf("%s (%s)", expand_string_message,
2046     (name[4] == 'c' || name[4] == 'm')?
2047       (isalpha(name[5])?
2048         US"6th character of a user-defined ACL variable must be a digit or underscore" :
2049         US"strict_acl_vars is set"    /* Syntax is OK, it has to be this */
2050       ) :
2051       US"user-defined ACL variables must start acl_c or acl_m");
2052 }
2053
2054
2055
2056 /*
2057 Load args from sub array to globals, and call acl_check().
2058 Sub array will be corrupted on return.
2059
2060 Returns:       OK         access is granted by an ACCEPT verb
2061                DISCARD    access is granted by a DISCARD verb
2062                FAIL       access is denied
2063                FAIL_DROP  access is denied; drop the connection
2064                DEFER      can't tell at the moment
2065                ERROR      disaster
2066 */
2067 static int
2068 eval_acl(uschar ** sub, int nsub, uschar ** user_msgp)
2069 {
2070 int i;
2071 int sav_narg = acl_narg;
2072 int ret;
2073 uschar * dummy_logmsg;
2074 extern int acl_where;
2075
2076 if(--nsub > nelem(acl_arg)) nsub = nelem(acl_arg);
2077 for (i = 0; i < nsub && sub[i+1]; i++)
2078   {
2079   uschar * tmp = acl_arg[i];
2080   acl_arg[i] = sub[i+1];        /* place callers args in the globals */
2081   sub[i+1] = tmp;               /* stash the old args using our caller's storage */
2082   }
2083 acl_narg = i;
2084 while (i < nsub)
2085   {
2086   sub[i+1] = acl_arg[i];
2087   acl_arg[i++] = NULL;
2088   }
2089
2090 DEBUG(D_expand)
2091   debug_printf("expanding: acl: %s  arg: %s%s\n",
2092     sub[0],
2093     acl_narg>0 ? acl_arg[0] : US"<none>",
2094     acl_narg>1 ? " +more"   : "");
2095
2096 ret = acl_eval(acl_where, sub[0], user_msgp, &dummy_logmsg);
2097
2098 for (i = 0; i < nsub; i++)
2099   acl_arg[i] = sub[i+1];        /* restore old args */
2100 acl_narg = sav_narg;
2101
2102 return ret;
2103 }
2104
2105
2106
2107
2108 /*************************************************
2109 *        Read and evaluate a condition           *
2110 *************************************************/
2111
2112 /*
2113 Arguments:
2114   s        points to the start of the condition text
2115   resetok  points to a BOOL which is written false if it is unsafe to
2116            free memory. Certain condition types (acl) may have side-effect
2117            allocation which must be preserved.
2118   yield    points to a BOOL to hold the result of the condition test;
2119            if NULL, we are just reading through a condition that is
2120            part of an "or" combination to check syntax, or in a state
2121            where the answer isn't required
2122
2123 Returns:   a pointer to the first character after the condition, or
2124            NULL after an error
2125 */
2126
2127 static const uschar *
2128 eval_condition(const uschar *s, BOOL *resetok, BOOL *yield)
2129 {
2130 BOOL testfor = TRUE;
2131 BOOL tempcond, combined_cond;
2132 BOOL *subcondptr;
2133 BOOL sub2_honour_dollar = TRUE;
2134 int i, rc, cond_type, roffset;
2135 int_eximarith_t num[2];
2136 struct stat statbuf;
2137 uschar name[256];
2138 const uschar *sub[10];
2139
2140 const pcre *re;
2141 const uschar *rerror;
2142
2143 for (;;)
2144   {
2145   while (isspace(*s)) s++;
2146   if (*s == '!') { testfor = !testfor; s++; } else break;
2147   }
2148
2149 /* Numeric comparisons are symbolic */
2150
2151 if (*s == '=' || *s == '>' || *s == '<')
2152   {
2153   int p = 0;
2154   name[p++] = *s++;
2155   if (*s == '=')
2156     {
2157     name[p++] = '=';
2158     s++;
2159     }
2160   name[p] = 0;
2161   }
2162
2163 /* All other conditions are named */
2164
2165 else s = read_name(name, 256, s, US"_");
2166
2167 /* If we haven't read a name, it means some non-alpha character is first. */
2168
2169 if (name[0] == 0)
2170   {
2171   expand_string_message = string_sprintf("condition name expected, "
2172     "but found \"%.16s\"", s);
2173   return NULL;
2174   }
2175
2176 /* Find which condition we are dealing with, and switch on it */
2177
2178 cond_type = chop_match(name, cond_table, nelem(cond_table));
2179 switch(cond_type)
2180   {
2181   /* def: tests for a non-empty variable, or for the existence of a header. If
2182   yield == NULL we are in a skipping state, and don't care about the answer. */
2183
2184   case ECOND_DEF:
2185   if (*s != ':')
2186     {
2187     expand_string_message = US"\":\" expected after \"def\"";
2188     return NULL;
2189     }
2190
2191   s = read_name(name, 256, s+1, US"_");
2192
2193   /* Test for a header's existence. If the name contains a closing brace
2194   character, this may be a user error where the terminating colon has been
2195   omitted. Set a flag to adjust a subsequent error message in this case. */
2196
2197   if (Ustrncmp(name, "h_", 2) == 0 ||
2198       Ustrncmp(name, "rh_", 3) == 0 ||
2199       Ustrncmp(name, "bh_", 3) == 0 ||
2200       Ustrncmp(name, "header_", 7) == 0 ||
2201       Ustrncmp(name, "rheader_", 8) == 0 ||
2202       Ustrncmp(name, "bheader_", 8) == 0)
2203     {
2204     s = read_header_name(name, 256, s);
2205     /* {-for-text-editors */
2206     if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
2207     if (yield != NULL) *yield =
2208       (find_header(name, TRUE, NULL, FALSE, NULL) != NULL) == testfor;
2209     }
2210
2211   /* Test for a variable's having a non-empty value. A non-existent variable
2212   causes an expansion failure. */
2213
2214   else
2215     {
2216     uschar *value = find_variable(name, TRUE, yield == NULL, NULL);
2217     if (value == NULL)
2218       {
2219       expand_string_message = (name[0] == 0)?
2220         string_sprintf("variable name omitted after \"def:\"") :
2221         string_sprintf("unknown variable \"%s\" after \"def:\"", name);
2222       check_variable_error_message(name);
2223       return NULL;
2224       }
2225     if (yield != NULL) *yield = (value[0] != 0) == testfor;
2226     }
2227
2228   return s;
2229
2230
2231   /* first_delivery tests for first delivery attempt */
2232
2233   case ECOND_FIRST_DELIVERY:
2234   if (yield != NULL) *yield = deliver_firsttime == testfor;
2235   return s;
2236
2237
2238   /* queue_running tests for any process started by a queue runner */
2239
2240   case ECOND_QUEUE_RUNNING:
2241   if (yield != NULL) *yield = (queue_run_pid != (pid_t)0) == testfor;
2242   return s;
2243
2244
2245   /* exists:  tests for file existence
2246        isip:  tests for any IP address
2247       isip4:  tests for an IPv4 address
2248       isip6:  tests for an IPv6 address
2249         pam:  does PAM authentication
2250      radius:  does RADIUS authentication
2251    ldapauth:  does LDAP authentication
2252     pwcheck:  does Cyrus SASL pwcheck authentication
2253   */
2254
2255   case ECOND_EXISTS:
2256   case ECOND_ISIP:
2257   case ECOND_ISIP4:
2258   case ECOND_ISIP6:
2259   case ECOND_PAM:
2260   case ECOND_RADIUS:
2261   case ECOND_LDAPAUTH:
2262   case ECOND_PWCHECK:
2263
2264   while (isspace(*s)) s++;
2265   if (*s != '{') goto COND_FAILED_CURLY_START;          /* }-for-text-editors */
2266
2267   sub[0] = expand_string_internal(s+1, TRUE, &s, yield == NULL, TRUE, resetok);
2268   if (sub[0] == NULL) return NULL;
2269   /* {-for-text-editors */
2270   if (*s++ != '}') goto COND_FAILED_CURLY_END;
2271
2272   if (yield == NULL) return s;   /* No need to run the test if skipping */
2273
2274   switch(cond_type)
2275     {
2276     case ECOND_EXISTS:
2277     if ((expand_forbid & RDO_EXISTS) != 0)
2278       {
2279       expand_string_message = US"File existence tests are not permitted";
2280       return NULL;
2281       }
2282     *yield = (Ustat(sub[0], &statbuf) == 0) == testfor;
2283     break;
2284
2285     case ECOND_ISIP:
2286     case ECOND_ISIP4:
2287     case ECOND_ISIP6:
2288     rc = string_is_ip_address(sub[0], NULL);
2289     *yield = ((cond_type == ECOND_ISIP)? (rc != 0) :
2290              (cond_type == ECOND_ISIP4)? (rc == 4) : (rc == 6)) == testfor;
2291     break;
2292
2293     /* Various authentication tests - all optionally compiled */
2294
2295     case ECOND_PAM:
2296     #ifdef SUPPORT_PAM
2297     rc = auth_call_pam(sub[0], &expand_string_message);
2298     goto END_AUTH;
2299     #else
2300     goto COND_FAILED_NOT_COMPILED;
2301     #endif  /* SUPPORT_PAM */
2302
2303     case ECOND_RADIUS:
2304     #ifdef RADIUS_CONFIG_FILE
2305     rc = auth_call_radius(sub[0], &expand_string_message);
2306     goto END_AUTH;
2307     #else
2308     goto COND_FAILED_NOT_COMPILED;
2309     #endif  /* RADIUS_CONFIG_FILE */
2310
2311     case ECOND_LDAPAUTH:
2312     #ifdef LOOKUP_LDAP
2313       {
2314       /* Just to keep the interface the same */
2315       BOOL do_cache;
2316       int old_pool = store_pool;
2317       store_pool = POOL_SEARCH;
2318       rc = eldapauth_find((void *)(-1), NULL, sub[0], Ustrlen(sub[0]), NULL,
2319         &expand_string_message, &do_cache);
2320       store_pool = old_pool;
2321       }
2322     goto END_AUTH;
2323     #else
2324     goto COND_FAILED_NOT_COMPILED;
2325     #endif  /* LOOKUP_LDAP */
2326
2327     case ECOND_PWCHECK:
2328     #ifdef CYRUS_PWCHECK_SOCKET
2329     rc = auth_call_pwcheck(sub[0], &expand_string_message);
2330     goto END_AUTH;
2331     #else
2332     goto COND_FAILED_NOT_COMPILED;
2333     #endif  /* CYRUS_PWCHECK_SOCKET */
2334
2335     #if defined(SUPPORT_PAM) || defined(RADIUS_CONFIG_FILE) || \
2336         defined(LOOKUP_LDAP) || defined(CYRUS_PWCHECK_SOCKET)
2337     END_AUTH:
2338     if (rc == ERROR || rc == DEFER) return NULL;
2339     *yield = (rc == OK) == testfor;
2340     #endif
2341     }
2342   return s;
2343
2344
2345   /* call ACL (in a conditional context).  Accept true, deny false.
2346   Defer is a forced-fail.  Anything set by message= goes to $value.
2347   Up to ten parameters are used; we use the braces round the name+args
2348   like the saslauthd condition does, to permit a variable number of args.
2349   See also the expansion-item version EITEM_ACL and the traditional
2350   acl modifier ACLC_ACL.
2351   Since the ACL may allocate new global variables, tell our caller to not
2352   reclaim memory.
2353   */
2354
2355   case ECOND_ACL:
2356     /* ${if acl {{name}{arg1}{arg2}...}  {yes}{no}} */
2357     {
2358     uschar *sub[10];
2359     uschar *user_msg;
2360     BOOL cond = FALSE;
2361     int size = 0;
2362     int ptr = 0;
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     *resetok = FALSE;
2377     if (yield != NULL) switch(eval_acl(sub, nelem(sub), &user_msg))
2378         {
2379         case OK:
2380           cond = TRUE;
2381         case FAIL:
2382           lookup_value = NULL;
2383           if (user_msg)
2384             {
2385             lookup_value = string_cat(NULL, &size, &ptr, user_msg, Ustrlen(user_msg));
2386             lookup_value[ptr] = '\0';
2387             }
2388           *yield = cond == testfor;
2389           break;
2390
2391         case DEFER:
2392           expand_string_forcedfail = TRUE;
2393         default:
2394           expand_string_message = string_sprintf("error from acl \"%s\"", sub[0]);
2395           return NULL;
2396         }
2397     return s;
2398     }
2399
2400
2401   /* saslauthd: does Cyrus saslauthd authentication. Four parameters are used:
2402
2403      ${if saslauthd {{username}{password}{service}{realm}}  {yes}{no}}
2404
2405   However, the last two are optional. That is why the whole set is enclosed
2406   in their own set of braces. */
2407
2408   case ECOND_SASLAUTHD:
2409 #ifndef CYRUS_SASLAUTHD_SOCKET
2410     goto COND_FAILED_NOT_COMPILED;
2411 #else
2412     {
2413     uschar *sub[4];
2414     while (isspace(*s)) s++;
2415     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2416     switch(read_subs(sub, nelem(sub), 2, &s, yield == NULL, TRUE, US"saslauthd",
2417                     resetok))
2418       {
2419       case 1: expand_string_message = US"too few arguments or bracketing "
2420         "error for saslauthd";
2421       case 2:
2422       case 3: return NULL;
2423       }
2424     if (sub[2] == NULL) sub[3] = NULL;  /* realm if no service */
2425     if (yield != NULL)
2426       {
2427       int rc = auth_call_saslauthd(sub[0], sub[1], sub[2], sub[3],
2428         &expand_string_message);
2429       if (rc == ERROR || rc == DEFER) return NULL;
2430       *yield = (rc == OK) == testfor;
2431       }
2432     return s;
2433     }
2434 #endif /* CYRUS_SASLAUTHD_SOCKET */
2435
2436
2437   /* symbolic operators for numeric and string comparison, and a number of
2438   other operators, all requiring two arguments.
2439
2440   crypteq:           encrypts plaintext and compares against an encrypted text,
2441                        using crypt(), crypt16(), MD5 or SHA-1
2442   inlist/inlisti:    checks if first argument is in the list of the second
2443   match:             does a regular expression match and sets up the numerical
2444                        variables if it succeeds
2445   match_address:     matches in an address list
2446   match_domain:      matches in a domain list
2447   match_ip:          matches a host list that is restricted to IP addresses
2448   match_local_part:  matches in a local part list
2449   */
2450
2451   case ECOND_MATCH_ADDRESS:
2452   case ECOND_MATCH_DOMAIN:
2453   case ECOND_MATCH_IP:
2454   case ECOND_MATCH_LOCAL_PART:
2455 #ifndef EXPAND_LISTMATCH_RHS
2456     sub2_honour_dollar = FALSE;
2457 #endif
2458     /* FALLTHROUGH */
2459
2460   case ECOND_CRYPTEQ:
2461   case ECOND_INLIST:
2462   case ECOND_INLISTI:
2463   case ECOND_MATCH:
2464
2465   case ECOND_NUM_L:     /* Numerical comparisons */
2466   case ECOND_NUM_LE:
2467   case ECOND_NUM_E:
2468   case ECOND_NUM_EE:
2469   case ECOND_NUM_G:
2470   case ECOND_NUM_GE:
2471
2472   case ECOND_STR_LT:    /* String comparisons */
2473   case ECOND_STR_LTI:
2474   case ECOND_STR_LE:
2475   case ECOND_STR_LEI:
2476   case ECOND_STR_EQ:
2477   case ECOND_STR_EQI:
2478   case ECOND_STR_GT:
2479   case ECOND_STR_GTI:
2480   case ECOND_STR_GE:
2481   case ECOND_STR_GEI:
2482
2483   for (i = 0; i < 2; i++)
2484     {
2485     /* Sometimes, we don't expand substrings; too many insecure configurations
2486     created using match_address{}{} and friends, where the second param
2487     includes information from untrustworthy sources. */
2488     BOOL honour_dollar = TRUE;
2489     if ((i > 0) && !sub2_honour_dollar)
2490       honour_dollar = FALSE;
2491
2492     while (isspace(*s)) s++;
2493     if (*s != '{')
2494       {
2495       if (i == 0) goto COND_FAILED_CURLY_START;
2496       expand_string_message = string_sprintf("missing 2nd string in {} "
2497         "after \"%s\"", name);
2498       return NULL;
2499       }
2500     sub[i] = expand_string_internal(s+1, TRUE, &s, yield == NULL,
2501         honour_dollar, resetok);
2502     if (sub[i] == NULL) return NULL;
2503     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2504
2505     /* Convert to numerical if required; we know that the names of all the
2506     conditions that compare numbers do not start with a letter. This just saves
2507     checking for them individually. */
2508
2509     if (!isalpha(name[0]) && yield != NULL)
2510       {
2511       if (sub[i][0] == 0)
2512         {
2513         num[i] = 0;
2514         DEBUG(D_expand)
2515           debug_printf("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
2525   /* Result not required */
2526
2527   if (yield == NULL) return s;
2528
2529   /* Do an appropriate comparison */
2530
2531   switch(cond_type)
2532     {
2533     case ECOND_NUM_E:
2534     case ECOND_NUM_EE:
2535     tempcond = (num[0] == num[1]);
2536     break;
2537
2538     case ECOND_NUM_G:
2539     tempcond = (num[0] > num[1]);
2540     break;
2541
2542     case ECOND_NUM_GE:
2543     tempcond = (num[0] >= num[1]);
2544     break;
2545
2546     case ECOND_NUM_L:
2547     tempcond = (num[0] < num[1]);
2548     break;
2549
2550     case ECOND_NUM_LE:
2551     tempcond = (num[0] <= num[1]);
2552     break;
2553
2554     case ECOND_STR_LT:
2555     tempcond = (Ustrcmp(sub[0], sub[1]) < 0);
2556     break;
2557
2558     case ECOND_STR_LTI:
2559     tempcond = (strcmpic(sub[0], sub[1]) < 0);
2560     break;
2561
2562     case ECOND_STR_LE:
2563     tempcond = (Ustrcmp(sub[0], sub[1]) <= 0);
2564     break;
2565
2566     case ECOND_STR_LEI:
2567     tempcond = (strcmpic(sub[0], sub[1]) <= 0);
2568     break;
2569
2570     case ECOND_STR_EQ:
2571     tempcond = (Ustrcmp(sub[0], sub[1]) == 0);
2572     break;
2573
2574     case ECOND_STR_EQI:
2575     tempcond = (strcmpic(sub[0], sub[1]) == 0);
2576     break;
2577
2578     case ECOND_STR_GT:
2579     tempcond = (Ustrcmp(sub[0], sub[1]) > 0);
2580     break;
2581
2582     case ECOND_STR_GTI:
2583     tempcond = (strcmpic(sub[0], sub[1]) > 0);
2584     break;
2585
2586     case ECOND_STR_GE:
2587     tempcond = (Ustrcmp(sub[0], sub[1]) >= 0);
2588     break;
2589
2590     case ECOND_STR_GEI:
2591     tempcond = (strcmpic(sub[0], sub[1]) >= 0);
2592     break;
2593
2594     case ECOND_MATCH:   /* Regular expression match */
2595     re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
2596       NULL);
2597     if (re == NULL)
2598       {
2599       expand_string_message = string_sprintf("regular expression error in "
2600         "\"%s\": %s at offset %d", sub[1], rerror, roffset);
2601       return NULL;
2602       }
2603     tempcond = regex_match_and_setup(re, sub[0], 0, -1);
2604     break;
2605
2606     case ECOND_MATCH_ADDRESS:  /* Match in an address list */
2607     rc = match_address_list(sub[0], TRUE, FALSE, &(sub[1]), NULL, -1, 0, NULL);
2608     goto MATCHED_SOMETHING;
2609
2610     case ECOND_MATCH_DOMAIN:   /* Match in a domain list */
2611     rc = match_isinlist(sub[0], &(sub[1]), 0, &domainlist_anchor, NULL,
2612       MCL_DOMAIN + MCL_NOEXPAND, TRUE, NULL);
2613     goto MATCHED_SOMETHING;
2614
2615     case ECOND_MATCH_IP:       /* Match IP address in a host list */
2616     if (sub[0][0] != 0 && string_is_ip_address(sub[0], NULL) == 0)
2617       {
2618       expand_string_message = string_sprintf("\"%s\" is not an IP address",
2619         sub[0]);
2620       return NULL;
2621       }
2622     else
2623       {
2624       unsigned int *nullcache = NULL;
2625       check_host_block cb;
2626
2627       cb.host_name = US"";
2628       cb.host_address = sub[0];
2629
2630       /* If the host address starts off ::ffff: it is an IPv6 address in
2631       IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2632       addresses. */
2633
2634       cb.host_ipv4 = (Ustrncmp(cb.host_address, "::ffff:", 7) == 0)?
2635         cb.host_address + 7 : cb.host_address;
2636
2637       rc = match_check_list(
2638              &sub[1],                   /* the list */
2639              0,                         /* separator character */
2640              &hostlist_anchor,          /* anchor pointer */
2641              &nullcache,                /* cache pointer */
2642              check_host,                /* function for testing */
2643              &cb,                       /* argument for function */
2644              MCL_HOST,                  /* type of check */
2645              sub[0],                    /* text for debugging */
2646              NULL);                     /* where to pass back data */
2647       }
2648     goto MATCHED_SOMETHING;
2649
2650     case ECOND_MATCH_LOCAL_PART:
2651     rc = match_isinlist(sub[0], &(sub[1]), 0, &localpartlist_anchor, NULL,
2652       MCL_LOCALPART + MCL_NOEXPAND, TRUE, NULL);
2653     /* Fall through */
2654     /* VVVVVVVVVVVV */
2655     MATCHED_SOMETHING:
2656     switch(rc)
2657       {
2658       case OK:
2659       tempcond = TRUE;
2660       break;
2661
2662       case FAIL:
2663       tempcond = FALSE;
2664       break;
2665
2666       case DEFER:
2667       expand_string_message = string_sprintf("unable to complete match "
2668         "against \"%s\": %s", sub[1], search_error_message);
2669       return NULL;
2670       }
2671
2672     break;
2673
2674     /* Various "encrypted" comparisons. If the second string starts with
2675     "{" then an encryption type is given. Default to crypt() or crypt16()
2676     (build-time choice). */
2677     /* }-for-text-editors */
2678
2679     case ECOND_CRYPTEQ:
2680     #ifndef SUPPORT_CRYPTEQ
2681     goto COND_FAILED_NOT_COMPILED;
2682     #else
2683     if (strncmpic(sub[1], US"{md5}", 5) == 0)
2684       {
2685       int sublen = Ustrlen(sub[1]+5);
2686       md5 base;
2687       uschar digest[16];
2688
2689       md5_start(&base);
2690       md5_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2691
2692       /* If the length that we are comparing against is 24, the MD5 digest
2693       is expressed as a base64 string. This is the way LDAP does it. However,
2694       some other software uses a straightforward hex representation. We assume
2695       this if the length is 32. Other lengths fail. */
2696
2697       if (sublen == 24)
2698         {
2699         uschar *coded = b64encode((uschar *)digest, 16);
2700         DEBUG(D_auth) debug_printf("crypteq: using MD5+B64 hashing\n"
2701           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2702         tempcond = (Ustrcmp(coded, sub[1]+5) == 0);
2703         }
2704       else if (sublen == 32)
2705         {
2706         int i;
2707         uschar coded[36];
2708         for (i = 0; i < 16; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2709         coded[32] = 0;
2710         DEBUG(D_auth) debug_printf("crypteq: using MD5+hex hashing\n"
2711           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2712         tempcond = (strcmpic(coded, sub[1]+5) == 0);
2713         }
2714       else
2715         {
2716         DEBUG(D_auth) debug_printf("crypteq: length for MD5 not 24 or 32: "
2717           "fail\n  crypted=%s\n", sub[1]+5);
2718         tempcond = FALSE;
2719         }
2720       }
2721
2722     else if (strncmpic(sub[1], US"{sha1}", 6) == 0)
2723       {
2724       int sublen = Ustrlen(sub[1]+6);
2725       sha1 base;
2726       uschar digest[20];
2727
2728       sha1_start(&base);
2729       sha1_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2730
2731       /* If the length that we are comparing against is 28, assume the SHA1
2732       digest is expressed as a base64 string. If the length is 40, assume a
2733       straightforward hex representation. Other lengths fail. */
2734
2735       if (sublen == 28)
2736         {
2737         uschar *coded = b64encode((uschar *)digest, 20);
2738         DEBUG(D_auth) debug_printf("crypteq: using SHA1+B64 hashing\n"
2739           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2740         tempcond = (Ustrcmp(coded, sub[1]+6) == 0);
2741         }
2742       else if (sublen == 40)
2743         {
2744         int i;
2745         uschar coded[44];
2746         for (i = 0; i < 20; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2747         coded[40] = 0;
2748         DEBUG(D_auth) debug_printf("crypteq: using SHA1+hex hashing\n"
2749           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2750         tempcond = (strcmpic(coded, sub[1]+6) == 0);
2751         }
2752       else
2753         {
2754         DEBUG(D_auth) debug_printf("crypteq: length for SHA-1 not 28 or 40: "
2755           "fail\n  crypted=%s\n", sub[1]+6);
2756         tempcond = FALSE;
2757         }
2758       }
2759
2760     else   /* {crypt} or {crypt16} and non-{ at start */
2761            /* }-for-text-editors */
2762       {
2763       int which = 0;
2764       uschar *coded;
2765
2766       if (strncmpic(sub[1], US"{crypt}", 7) == 0)
2767         {
2768         sub[1] += 7;
2769         which = 1;
2770         }
2771       else if (strncmpic(sub[1], US"{crypt16}", 9) == 0)
2772         {
2773         sub[1] += 9;
2774         which = 2;
2775         }
2776       else if (sub[1][0] == '{')                /* }-for-text-editors */
2777         {
2778         expand_string_message = string_sprintf("unknown encryption mechanism "
2779           "in \"%s\"", sub[1]);
2780         return NULL;
2781         }
2782
2783       switch(which)
2784         {
2785         case 0:  coded = US DEFAULT_CRYPT(CS sub[0], CS sub[1]); break;
2786         case 1:  coded = US crypt(CS sub[0], CS sub[1]); break;
2787         default: coded = US crypt16(CS sub[0], CS sub[1]); break;
2788         }
2789
2790       #define STR(s) # s
2791       #define XSTR(s) STR(s)
2792       DEBUG(D_auth) debug_printf("crypteq: using %s()\n"
2793         "  subject=%s\n  crypted=%s\n",
2794         which == 0 ? XSTR(DEFAULT_CRYPT) : which == 1 ? "crypt" : "crypt16",
2795         coded, sub[1]);
2796       #undef STR
2797       #undef XSTR
2798
2799       /* If the encrypted string contains fewer than two characters (for the
2800       salt), force failure. Otherwise we get false positives: with an empty
2801       string the yield of crypt() is an empty string! */
2802
2803       if (coded)
2804         tempcond = Ustrlen(sub[1]) < 2 ? FALSE : Ustrcmp(coded, sub[1]) == 0;
2805       else if (errno == EINVAL)
2806         tempcond = FALSE;
2807       else
2808         {
2809         expand_string_message = string_sprintf("crypt error: %s\n",
2810           US strerror(errno));
2811         return NULL;
2812         }
2813       }
2814     break;
2815     #endif  /* SUPPORT_CRYPTEQ */
2816
2817     case ECOND_INLIST:
2818     case ECOND_INLISTI:
2819       {
2820       const uschar * list = sub[1];
2821       int sep = 0;
2822       uschar *save_iterate_item = iterate_item;
2823       int (*compare)(const uschar *, const uschar *);
2824
2825       DEBUG(D_expand) debug_printf("condition: %s\n", name);
2826
2827       tempcond = FALSE;
2828       compare = cond_type == ECOND_INLISTI
2829         ? strcmpic : (int (*)(const uschar *, const uschar *)) strcmp;
2830
2831       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)))
2832         if (compare(sub[0], iterate_item) == 0)
2833           {
2834           tempcond = TRUE;
2835           break;
2836           }
2837       iterate_item = save_iterate_item;
2838       }
2839
2840     }   /* Switch for comparison conditions */
2841
2842   *yield = tempcond == testfor;
2843   return s;    /* End of comparison conditions */
2844
2845
2846   /* and/or: computes logical and/or of several conditions */
2847
2848   case ECOND_AND:
2849   case ECOND_OR:
2850   subcondptr = (yield == NULL)? NULL : &tempcond;
2851   combined_cond = (cond_type == ECOND_AND);
2852
2853   while (isspace(*s)) s++;
2854   if (*s++ != '{') goto COND_FAILED_CURLY_START;        /* }-for-text-editors */
2855
2856   for (;;)
2857     {
2858     while (isspace(*s)) s++;
2859     /* {-for-text-editors */
2860     if (*s == '}') break;
2861     if (*s != '{')                                      /* }-for-text-editors */
2862       {
2863       expand_string_message = string_sprintf("each subcondition "
2864         "inside an \"%s{...}\" condition must be in its own {}", name);
2865       return NULL;
2866       }
2867
2868     if (!(s = eval_condition(s+1, resetok, subcondptr)))
2869       {
2870       expand_string_message = string_sprintf("%s inside \"%s{...}\" condition",
2871         expand_string_message, name);
2872       return NULL;
2873       }
2874     while (isspace(*s)) s++;
2875
2876     /* {-for-text-editors */
2877     if (*s++ != '}')
2878       {
2879       /* {-for-text-editors */
2880       expand_string_message = string_sprintf("missing } at end of condition "
2881         "inside \"%s\" group", name);
2882       return NULL;
2883       }
2884
2885     if (yield != NULL)
2886       {
2887       if (cond_type == ECOND_AND)
2888         {
2889         combined_cond &= tempcond;
2890         if (!combined_cond) subcondptr = NULL;  /* once false, don't */
2891         }                                       /* evaluate any more */
2892       else
2893         {
2894         combined_cond |= tempcond;
2895         if (combined_cond) subcondptr = NULL;   /* once true, don't */
2896         }                                       /* evaluate any more */
2897       }
2898     }
2899
2900   if (yield != NULL) *yield = (combined_cond == testfor);
2901   return ++s;
2902
2903
2904   /* forall/forany: iterates a condition with different values */
2905
2906   case ECOND_FORALL:
2907   case ECOND_FORANY:
2908     {
2909     const uschar * list;
2910     int sep = 0;
2911     uschar *save_iterate_item = iterate_item;
2912
2913     DEBUG(D_expand) debug_printf("condition: %s\n", name);
2914
2915     while (isspace(*s)) s++;
2916     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2917     sub[0] = expand_string_internal(s, TRUE, &s, (yield == NULL), TRUE, resetok);
2918     if (sub[0] == NULL) return NULL;
2919     /* {-for-text-editors */
2920     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2921
2922     while (isspace(*s)) s++;
2923     if (*s++ != '{') goto COND_FAILED_CURLY_START;      /* }-for-text-editors */
2924
2925     sub[1] = s;
2926
2927     /* Call eval_condition once, with result discarded (as if scanning a
2928     "false" part). This allows us to find the end of the condition, because if
2929     the list it empty, we won't actually evaluate the condition for real. */
2930
2931     if (!(s = eval_condition(sub[1], resetok, NULL)))
2932       {
2933       expand_string_message = string_sprintf("%s inside \"%s\" condition",
2934         expand_string_message, name);
2935       return NULL;
2936       }
2937     while (isspace(*s)) s++;
2938
2939     /* {-for-text-editors */
2940     if (*s++ != '}')
2941       {
2942       /* {-for-text-editors */
2943       expand_string_message = string_sprintf("missing } at end of condition "
2944         "inside \"%s\"", name);
2945       return NULL;
2946       }
2947
2948     if (yield != NULL) *yield = !testfor;
2949     list = sub[0];
2950     while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
2951       {
2952       DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
2953       if (!eval_condition(sub[1], resetok, &tempcond))
2954         {
2955         expand_string_message = string_sprintf("%s inside \"%s\" condition",
2956           expand_string_message, name);
2957         iterate_item = save_iterate_item;
2958         return NULL;
2959         }
2960       DEBUG(D_expand) debug_printf("%s: condition evaluated to %s\n", name,
2961         tempcond? "true":"false");
2962
2963       if (yield != NULL) *yield = (tempcond == testfor);
2964       if (tempcond == (cond_type == ECOND_FORANY)) break;
2965       }
2966
2967     iterate_item = save_iterate_item;
2968     return s;
2969     }
2970
2971
2972   /* The bool{} expansion condition maps a string to boolean.
2973   The values supported should match those supported by the ACL condition
2974   (acl.c, ACLC_CONDITION) so that we keep to a minimum the different ideas
2975   of true/false.  Note that Router "condition" rules have a different
2976   interpretation, where general data can be used and only a few values
2977   map to FALSE.
2978   Note that readconf.c boolean matching, for boolean configuration options,
2979   only matches true/yes/false/no.
2980   The bool_lax{} condition matches the Router logic, which is much more
2981   liberal. */
2982   case ECOND_BOOL:
2983   case ECOND_BOOL_LAX:
2984     {
2985     uschar *sub_arg[1];
2986     uschar *t, *t2;
2987     uschar *ourname;
2988     size_t len;
2989     BOOL boolvalue = FALSE;
2990     while (isspace(*s)) s++;
2991     if (*s != '{') goto COND_FAILED_CURLY_START;        /* }-for-text-editors */
2992     ourname = cond_type == ECOND_BOOL_LAX ? US"bool_lax" : US"bool";
2993     switch(read_subs(sub_arg, 1, 1, &s, yield == NULL, FALSE, ourname, resetok))
2994       {
2995       case 1: expand_string_message = string_sprintf(
2996                   "too few arguments or bracketing error for %s",
2997                   ourname);
2998       /*FALLTHROUGH*/
2999       case 2:
3000       case 3: return NULL;
3001       }
3002     t = sub_arg[0];
3003     while (isspace(*t)) t++;
3004     len = Ustrlen(t);
3005     if (len)
3006       {
3007       /* trailing whitespace: seems like a good idea to ignore it too */
3008       t2 = t + len - 1;
3009       while (isspace(*t2)) t2--;
3010       if (t2 != (t + len))
3011         {
3012         *++t2 = '\0';
3013         len = t2 - t;
3014         }
3015       }
3016     DEBUG(D_expand)
3017       debug_printf("considering %s: %s\n", ourname, len ? t : US"<empty>");
3018     /* logic for the lax case from expand_check_condition(), which also does
3019     expands, and the logic is both short and stable enough that there should
3020     be no maintenance burden from replicating it. */
3021     if (len == 0)
3022       boolvalue = FALSE;
3023     else if (*t == '-'
3024              ? Ustrspn(t+1, "0123456789") == len-1
3025              : Ustrspn(t,   "0123456789") == len)
3026       {
3027       boolvalue = (Uatoi(t) == 0) ? FALSE : TRUE;
3028       /* expand_check_condition only does a literal string "0" check */
3029       if ((cond_type == ECOND_BOOL_LAX) && (len > 1))
3030         boolvalue = TRUE;
3031       }
3032     else if (strcmpic(t, US"true") == 0 || strcmpic(t, US"yes") == 0)
3033       boolvalue = TRUE;
3034     else if (strcmpic(t, US"false") == 0 || strcmpic(t, US"no") == 0)
3035       boolvalue = FALSE;
3036     else if (cond_type == ECOND_BOOL_LAX)
3037       boolvalue = TRUE;
3038     else
3039       {
3040       expand_string_message = string_sprintf("unrecognised boolean "
3041        "value \"%s\"", t);
3042       return NULL;
3043       }
3044     if (yield != NULL) *yield = (boolvalue == testfor);
3045     return s;
3046     }
3047
3048   /* Unknown condition */
3049
3050   default:
3051   expand_string_message = string_sprintf("unknown condition \"%s\"", name);
3052   return NULL;
3053   }   /* End switch on condition type */
3054
3055 /* Missing braces at start and end of data */
3056
3057 COND_FAILED_CURLY_START:
3058 expand_string_message = string_sprintf("missing { after \"%s\"", name);
3059 return NULL;
3060
3061 COND_FAILED_CURLY_END:
3062 expand_string_message = string_sprintf("missing } at end of \"%s\" condition",
3063   name);
3064 return NULL;
3065
3066 /* A condition requires code that is not compiled */
3067
3068 #if !defined(SUPPORT_PAM) || !defined(RADIUS_CONFIG_FILE) || \
3069     !defined(LOOKUP_LDAP) || !defined(CYRUS_PWCHECK_SOCKET) || \
3070     !defined(SUPPORT_CRYPTEQ) || !defined(CYRUS_SASLAUTHD_SOCKET)
3071 COND_FAILED_NOT_COMPILED:
3072 expand_string_message = string_sprintf("support for \"%s\" not compiled",
3073   name);
3074 return NULL;
3075 #endif
3076 }
3077
3078
3079
3080
3081 /*************************************************
3082 *          Save numerical variables              *
3083 *************************************************/
3084
3085 /* This function is called from items such as "if" that want to preserve and
3086 restore the numbered variables.
3087
3088 Arguments:
3089   save_expand_string    points to an array of pointers to set
3090   save_expand_nlength   points to an array of ints for the lengths
3091
3092 Returns:                the value of expand max to save
3093 */
3094
3095 static int
3096 save_expand_strings(uschar **save_expand_nstring, int *save_expand_nlength)
3097 {
3098 int i;
3099 for (i = 0; i <= expand_nmax; i++)
3100   {
3101   save_expand_nstring[i] = expand_nstring[i];
3102   save_expand_nlength[i] = expand_nlength[i];
3103   }
3104 return expand_nmax;
3105 }
3106
3107
3108
3109 /*************************************************
3110 *           Restore numerical variables          *
3111 *************************************************/
3112
3113 /* This function restored saved values of numerical strings.
3114
3115 Arguments:
3116   save_expand_nmax      the number of strings to restore
3117   save_expand_string    points to an array of pointers
3118   save_expand_nlength   points to an array of ints
3119
3120 Returns:                nothing
3121 */
3122
3123 static void
3124 restore_expand_strings(int save_expand_nmax, uschar **save_expand_nstring,
3125   int *save_expand_nlength)
3126 {
3127 int i;
3128 expand_nmax = save_expand_nmax;
3129 for (i = 0; i <= expand_nmax; i++)
3130   {
3131   expand_nstring[i] = save_expand_nstring[i];
3132   expand_nlength[i] = save_expand_nlength[i];
3133   }
3134 }
3135
3136
3137
3138
3139
3140 /*************************************************
3141 *            Handle yes/no substrings            *
3142 *************************************************/
3143
3144 /* This function is used by ${if}, ${lookup} and ${extract} to handle the
3145 alternative substrings that depend on whether or not the condition was true,
3146 or the lookup or extraction succeeded. The substrings always have to be
3147 expanded, to check their syntax, but "skipping" is set when the result is not
3148 needed - this avoids unnecessary nested lookups.
3149
3150 Arguments:
3151   skipping       TRUE if we were skipping when this item was reached
3152   yes            TRUE if the first string is to be used, else use the second
3153   save_lookup    a value to put back into lookup_value before the 2nd expansion
3154   sptr           points to the input string pointer
3155   yieldptr       points to the output string pointer
3156   sizeptr        points to the output string size
3157   ptrptr         points to the output string pointer
3158   type           "lookup", "if", "extract", "run", "env", "listextract" or
3159                  "certextract" for error message
3160   resetok        if not NULL, pointer to flag - write FALSE if unsafe to reset
3161                 the store.
3162
3163 Returns:         0 OK; lookup_value has been reset to save_lookup
3164                  1 expansion failed
3165                  2 expansion failed because of bracketing error
3166 */
3167
3168 static int
3169 process_yesno(BOOL skipping, BOOL yes, uschar *save_lookup, const uschar **sptr,
3170   uschar **yieldptr, int *sizeptr, int *ptrptr, uschar *type, BOOL *resetok)
3171 {
3172 int rc = 0;
3173 const uschar *s = *sptr;    /* Local value */
3174 uschar *sub1, *sub2;
3175
3176 /* If there are no following strings, we substitute the contents of $value for
3177 lookups and for extractions in the success case. For the ${if item, the string
3178 "true" is substituted. In the fail case, nothing is substituted for all three
3179 items. */
3180
3181 while (isspace(*s)) s++;
3182 if (*s == '}')
3183   {
3184   if (type[0] == 'i')
3185     {
3186     if (yes) *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, US"true", 4);
3187     }
3188   else
3189     {
3190     if (yes && lookup_value)
3191       *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, lookup_value,
3192         Ustrlen(lookup_value));
3193     lookup_value = save_lookup;
3194     }
3195   s++;
3196   goto RETURN;
3197   }
3198
3199 /* The first following string must be braced. */
3200
3201 if (*s++ != '{') goto FAILED_CURLY;
3202
3203 /* Expand the first substring. Forced failures are noticed only if we actually
3204 want this string. Set skipping in the call in the fail case (this will always
3205 be the case if we were already skipping). */
3206
3207 sub1 = expand_string_internal(s, TRUE, &s, !yes, TRUE, resetok);
3208 if (sub1 == NULL && (yes || !expand_string_forcedfail)) goto FAILED;
3209 expand_string_forcedfail = FALSE;
3210 if (*s++ != '}') goto FAILED_CURLY;
3211
3212 /* If we want the first string, add it to the output */
3213
3214 if (yes)
3215   *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub1, Ustrlen(sub1));
3216
3217 /* If this is called from a lookup/env or a (cert)extract, we want to restore
3218 $value to what it was at the start of the item, so that it has this value
3219 during the second string expansion. For the call from "if" or "run" to this
3220 function, save_lookup is set to lookup_value, so that this statement does
3221 nothing. */
3222
3223 lookup_value = save_lookup;
3224
3225 /* There now follows either another substring, or "fail", or nothing. This
3226 time, forced failures are noticed only if we want the second string. We must
3227 set skipping in the nested call if we don't want this string, or if we were
3228 already skipping. */
3229
3230 while (isspace(*s)) s++;
3231 if (*s == '{')
3232   {
3233   sub2 = expand_string_internal(s+1, TRUE, &s, yes || skipping, TRUE, resetok);
3234   if (sub2 == NULL && (!yes || !expand_string_forcedfail)) goto FAILED;
3235   expand_string_forcedfail = FALSE;
3236   if (*s++ != '}') goto FAILED_CURLY;
3237
3238   /* If we want the second string, add it to the output */
3239
3240   if (!yes)
3241     *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub2, Ustrlen(sub2));
3242   }
3243
3244 /* If there is no second string, but the word "fail" is present when the use of
3245 the second string is wanted, set a flag indicating it was a forced failure
3246 rather than a syntactic error. Swallow the terminating } in case this is nested
3247 inside another lookup or if or extract. */
3248
3249 else if (*s != '}')
3250   {
3251   uschar name[256];
3252   /* deconst cast ok here as source is s anyway */
3253   s = US read_name(name, sizeof(name), s, US"_");
3254   if (Ustrcmp(name, "fail") == 0)
3255     {
3256     if (!yes && !skipping)
3257       {
3258       while (isspace(*s)) s++;
3259       if (*s++ != '}') goto FAILED_CURLY;
3260       expand_string_message =
3261         string_sprintf("\"%s\" failed and \"fail\" requested", type);
3262       expand_string_forcedfail = TRUE;
3263       goto FAILED;
3264       }
3265     }
3266   else
3267     {
3268     expand_string_message =
3269       string_sprintf("syntax error in \"%s\" item - \"fail\" expected", type);
3270     goto FAILED;
3271     }
3272   }
3273
3274 /* All we have to do now is to check on the final closing brace. */
3275
3276 while (isspace(*s)) s++;
3277 if (*s++ == '}') goto RETURN;
3278
3279 /* Get here if there is a bracketing failure */
3280
3281 FAILED_CURLY:
3282 rc++;
3283
3284 /* Get here for other failures */
3285
3286 FAILED:
3287 rc++;
3288
3289 /* Update the input pointer value before returning */
3290
3291 RETURN:
3292 *sptr = s;
3293 return rc;
3294 }
3295
3296
3297
3298
3299 /*************************************************
3300 *    Handle MD5 or SHA-1 computation for HMAC    *
3301 *************************************************/
3302
3303 /* These are some wrapping functions that enable the HMAC code to be a bit
3304 cleaner. A good compiler will spot the tail recursion.
3305
3306 Arguments:
3307   type         HMAC_MD5 or HMAC_SHA1
3308   remaining    are as for the cryptographic hash functions
3309
3310 Returns:       nothing
3311 */
3312
3313 static void
3314 chash_start(int type, void *base)
3315 {
3316 if (type == HMAC_MD5)
3317   md5_start((md5 *)base);
3318 else
3319   sha1_start((sha1 *)base);
3320 }
3321
3322 static void
3323 chash_mid(int type, void *base, uschar *string)
3324 {
3325 if (type == HMAC_MD5)
3326   md5_mid((md5 *)base, string);
3327 else
3328   sha1_mid((sha1 *)base, string);
3329 }
3330
3331 static void
3332 chash_end(int type, void *base, uschar *string, int length, uschar *digest)
3333 {
3334 if (type == HMAC_MD5)
3335   md5_end((md5 *)base, string, length, digest);
3336 else
3337   sha1_end((sha1 *)base, string, length, digest);
3338 }
3339
3340
3341
3342
3343
3344 /********************************************************
3345 * prvs: Get last three digits of days since Jan 1, 1970 *
3346 ********************************************************/
3347
3348 /* This is needed to implement the "prvs" BATV reverse
3349    path signing scheme
3350
3351 Argument: integer "days" offset to add or substract to
3352           or from the current number of days.
3353
3354 Returns:  pointer to string containing the last three
3355           digits of the number of days since Jan 1, 1970,
3356           modified by the offset argument, NULL if there
3357           was an error in the conversion.
3358
3359 */
3360
3361 static uschar *
3362 prvs_daystamp(int day_offset)
3363 {
3364 uschar *days = store_get(32);                /* Need at least 24 for cases */
3365 (void)string_format(days, 32, TIME_T_FMT,    /* where TIME_T_FMT is %lld */
3366   (time(NULL) + day_offset*86400)/86400);
3367 return (Ustrlen(days) >= 3) ? &days[Ustrlen(days)-3] : US"100";
3368 }
3369
3370
3371
3372 /********************************************************
3373 *   prvs: perform HMAC-SHA1 computation of prvs bits    *
3374 ********************************************************/
3375
3376 /* This is needed to implement the "prvs" BATV reverse
3377    path signing scheme
3378
3379 Arguments:
3380   address RFC2821 Address to use
3381       key The key to use (must be less than 64 characters
3382           in size)
3383   key_num Single-digit key number to use. Defaults to
3384           '0' when NULL.
3385
3386 Returns:  pointer to string containing the first three
3387           bytes of the final hash in hex format, NULL if
3388           there was an error in the process.
3389 */
3390
3391 static uschar *
3392 prvs_hmac_sha1(uschar *address, uschar *key, uschar *key_num, uschar *daystamp)
3393 {
3394 uschar *hash_source, *p;
3395 int size = 0,offset = 0,i;
3396 sha1 sha1_base;
3397 void *use_base = &sha1_base;
3398 uschar innerhash[20];
3399 uschar finalhash[20];
3400 uschar innerkey[64];
3401 uschar outerkey[64];
3402 uschar *finalhash_hex = store_get(40);
3403
3404 if (key_num == NULL)
3405   key_num = US"0";
3406
3407 if (Ustrlen(key) > 64)
3408   return NULL;
3409
3410 hash_source = string_cat(NULL,&size,&offset,key_num,1);
3411 hash_source = string_cat(hash_source,&size,&offset,daystamp,3);
3412 hash_source = string_cat(hash_source,&size,&offset,address,Ustrlen(address));
3413 hash_source[offset] = '\0';
3414
3415 DEBUG(D_expand) debug_printf("prvs: hash source is '%s'\n", hash_source);
3416
3417 memset(innerkey, 0x36, 64);
3418 memset(outerkey, 0x5c, 64);
3419
3420 for (i = 0; i < Ustrlen(key); i++)
3421   {
3422   innerkey[i] ^= key[i];
3423   outerkey[i] ^= key[i];
3424   }
3425
3426 chash_start(HMAC_SHA1, use_base);
3427 chash_mid(HMAC_SHA1, use_base, innerkey);
3428 chash_end(HMAC_SHA1, use_base, hash_source, offset, innerhash);
3429
3430 chash_start(HMAC_SHA1, use_base);
3431 chash_mid(HMAC_SHA1, use_base, outerkey);
3432 chash_end(HMAC_SHA1, use_base, innerhash, 20, finalhash);
3433
3434 p = finalhash_hex;
3435 for (i = 0; i < 3; i++)
3436   {
3437   *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
3438   *p++ = hex_digits[finalhash[i] & 0x0f];
3439   }
3440 *p = '\0';
3441
3442 return finalhash_hex;
3443 }
3444
3445
3446
3447
3448 /*************************************************
3449 *        Join a file onto the output string      *
3450 *************************************************/
3451
3452 /* This is used for readfile/readsock and after a run expansion.
3453 It joins the contents of a file onto the output string, globally replacing
3454 newlines with a given string (optionally).
3455
3456 Arguments:
3457   f            the FILE
3458   yield        pointer to the expandable string
3459   sizep        pointer to the current size
3460   ptrp         pointer to the current position
3461   eol          newline replacement string, or NULL
3462
3463 Returns:       new value of string pointer
3464 */
3465
3466 static uschar *
3467 cat_file(FILE *f, uschar *yield, int *sizep, int *ptrp, uschar *eol)
3468 {
3469 int eollen = eol ? Ustrlen(eol) : 0;
3470 uschar buffer[1024];
3471
3472 while (Ufgets(buffer, sizeof(buffer), f))
3473   {
3474   int len = Ustrlen(buffer);
3475   if (eol && buffer[len-1] == '\n') len--;
3476   yield = string_cat(yield, sizep, ptrp, buffer, len);
3477   if (buffer[len] != 0)
3478     yield = string_cat(yield, sizep, ptrp, eol, eollen);
3479   }
3480
3481 if (yield) yield[*ptrp] = 0;
3482
3483 return yield;
3484 }
3485
3486
3487
3488
3489 /*************************************************
3490 *          Evaluate numeric expression           *
3491 *************************************************/
3492
3493 /* This is a set of mutually recursive functions that evaluate an arithmetic
3494 expression involving + - * / % & | ^ ~ << >> and parentheses. The only one of
3495 these functions that is called from elsewhere is eval_expr, whose interface is:
3496
3497 Arguments:
3498   sptr        pointer to the pointer to the string - gets updated
3499   decimal     TRUE if numbers are to be assumed decimal
3500   error       pointer to where to put an error message - must be NULL on input
3501   endket      TRUE if ')' must terminate - FALSE for external call
3502
3503 Returns:      on success: the value of the expression, with *error still NULL
3504               on failure: an undefined value, with *error = a message
3505 */
3506
3507 static int_eximarith_t eval_op_or(uschar **, BOOL, uschar **);
3508
3509
3510 static int_eximarith_t
3511 eval_expr(uschar **sptr, BOOL decimal, uschar **error, BOOL endket)
3512 {
3513 uschar *s = *sptr;
3514 int_eximarith_t x = eval_op_or(&s, decimal, error);
3515 if (*error == NULL)
3516   {
3517   if (endket)
3518     {
3519     if (*s != ')')
3520       *error = US"expecting closing parenthesis";
3521     else
3522       while (isspace(*(++s)));
3523     }
3524   else if (*s != 0) *error = US"expecting operator";
3525   }
3526 *sptr = s;
3527 return x;
3528 }
3529
3530
3531 static int_eximarith_t
3532 eval_number(uschar **sptr, BOOL decimal, uschar **error)
3533 {
3534 register int c;
3535 int_eximarith_t n;
3536 uschar *s = *sptr;
3537 while (isspace(*s)) s++;
3538 c = *s;
3539 if (isdigit(c))
3540   {
3541   int count;
3542   (void)sscanf(CS s, (decimal? SC_EXIM_DEC "%n" : SC_EXIM_ARITH "%n"), &n, &count);
3543   s += count;
3544   switch (tolower(*s))
3545     {
3546     default: break;
3547     case 'k': n *= 1024; s++; break;
3548     case 'm': n *= 1024*1024; s++; break;
3549     case 'g': n *= 1024*1024*1024; s++; break;
3550     }
3551   while (isspace (*s)) s++;
3552   }
3553 else if (c == '(')
3554   {
3555   s++;
3556   n = eval_expr(&s, decimal, error, 1);
3557   }
3558 else
3559   {
3560   *error = US"expecting number or opening parenthesis";
3561   n = 0;
3562   }
3563 *sptr = s;
3564 return n;
3565 }
3566
3567
3568 static int_eximarith_t
3569 eval_op_unary(uschar **sptr, BOOL decimal, uschar **error)
3570 {
3571 uschar *s = *sptr;
3572 int_eximarith_t x;
3573 while (isspace(*s)) s++;
3574 if (*s == '+' || *s == '-' || *s == '~')
3575   {
3576   int op = *s++;
3577   x = eval_op_unary(&s, decimal, error);
3578   if (op == '-') x = -x;
3579     else if (op == '~') x = ~x;
3580   }
3581 else
3582   {
3583   x = eval_number(&s, decimal, error);
3584   }
3585 *sptr = s;
3586 return x;
3587 }
3588
3589
3590 static int_eximarith_t
3591 eval_op_mult(uschar **sptr, BOOL decimal, uschar **error)
3592 {
3593 uschar *s = *sptr;
3594 int_eximarith_t x = eval_op_unary(&s, decimal, error);
3595 if (*error == NULL)
3596   {
3597   while (*s == '*' || *s == '/' || *s == '%')
3598     {
3599     int op = *s++;
3600     int_eximarith_t y = eval_op_unary(&s, decimal, error);
3601     if (*error != NULL) break;
3602     /* SIGFPE both on div/mod by zero and on INT_MIN / -1, which would give
3603      * a value of INT_MAX+1. Note that INT_MIN * -1 gives INT_MIN for me, which
3604      * is a bug somewhere in [gcc 4.2.1, FreeBSD, amd64].  In fact, -N*-M where
3605      * -N*M is INT_MIN will yielf INT_MIN.
3606      * Since we don't support floating point, this is somewhat simpler.
3607      * Ideally, we'd return an error, but since we overflow for all other
3608      * arithmetic, consistency suggests otherwise, but what's the correct value
3609      * to use?  There is none.
3610      * The C standard guarantees overflow for unsigned arithmetic but signed
3611      * overflow invokes undefined behaviour; in practice, this is overflow
3612      * except for converting INT_MIN to INT_MAX+1.  We also can't guarantee
3613      * that long/longlong larger than int are available, or we could just work
3614      * with larger types.  We should consider whether to guarantee 32bit eval
3615      * and 64-bit working variables, with errors returned.  For now ...
3616      * So, the only SIGFPEs occur with a non-shrinking div/mod, thus -1; we
3617      * can just let the other invalid results occur otherwise, as they have
3618      * until now.  For this one case, we can coerce.
3619      */
3620     if (y == -1 && x == EXIM_ARITH_MIN && op != '*')
3621       {
3622       DEBUG(D_expand)
3623         debug_printf("Integer exception dodging: " PR_EXIM_ARITH "%c-1 coerced to " PR_EXIM_ARITH "\n",
3624             EXIM_ARITH_MIN, op, EXIM_ARITH_MAX);
3625       x = EXIM_ARITH_MAX;
3626       continue;
3627       }
3628     if (op == '*')
3629       x *= y;
3630     else
3631       {
3632       if (y == 0)
3633         {
3634         *error = (op == '/') ? US"divide by zero" : US"modulo by zero";
3635         x = 0;
3636         break;
3637         }
3638       if (op == '/')
3639         x /= y;
3640       else
3641         x %= y;
3642       }
3643     }
3644   }
3645 *sptr = s;
3646 return x;
3647 }
3648
3649
3650 static int_eximarith_t
3651 eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
3652 {
3653 uschar *s = *sptr;
3654 int_eximarith_t x = eval_op_mult(&s, decimal, error);
3655 if (*error == NULL)
3656   {
3657   while (*s == '+' || *s == '-')
3658     {
3659     int op = *s++;
3660     int_eximarith_t y = eval_op_mult(&s, decimal, error);
3661     if (*error != NULL) break;
3662     if (op == '+') x += y; else x -= y;
3663     }
3664   }
3665 *sptr = s;
3666 return x;
3667 }
3668
3669
3670 static int_eximarith_t
3671 eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
3672 {
3673 uschar *s = *sptr;
3674 int_eximarith_t x = eval_op_sum(&s, decimal, error);
3675 if (*error == NULL)
3676   {
3677   while ((*s == '<' || *s == '>') && s[1] == s[0])
3678     {
3679     int_eximarith_t y;
3680     int op = *s++;
3681     s++;
3682     y = eval_op_sum(&s, decimal, error);
3683     if (*error != NULL) break;
3684     if (op == '<') x <<= y; else x >>= y;
3685     }
3686   }
3687 *sptr = s;
3688 return x;
3689 }
3690
3691
3692 static int_eximarith_t
3693 eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
3694 {
3695 uschar *s = *sptr;
3696 int_eximarith_t x = eval_op_shift(&s, decimal, error);
3697 if (*error == NULL)
3698   {
3699   while (*s == '&')
3700     {
3701     int_eximarith_t y;
3702     s++;
3703     y = eval_op_shift(&s, decimal, error);
3704     if (*error != NULL) break;
3705     x &= y;
3706     }
3707   }
3708 *sptr = s;
3709 return x;
3710 }
3711
3712
3713 static int_eximarith_t
3714 eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
3715 {
3716 uschar *s = *sptr;
3717 int_eximarith_t x = eval_op_and(&s, decimal, error);
3718 if (*error == NULL)
3719   {
3720   while (*s == '^')
3721     {
3722     int_eximarith_t y;
3723     s++;
3724     y = eval_op_and(&s, decimal, error);
3725     if (*error != NULL) break;
3726     x ^= y;
3727     }
3728   }
3729 *sptr = s;
3730 return x;
3731 }
3732
3733
3734 static int_eximarith_t
3735 eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
3736 {
3737 uschar *s = *sptr;
3738 int_eximarith_t x = eval_op_xor(&s, decimal, error);
3739 if (*error == NULL)
3740   {
3741   while (*s == '|')
3742     {
3743     int_eximarith_t y;
3744     s++;
3745     y = eval_op_xor(&s, decimal, error);
3746     if (*error != NULL) break;
3747     x |= y;
3748     }
3749   }
3750 *sptr = s;
3751 return x;
3752 }
3753
3754
3755
3756 /*************************************************
3757 *                 Expand string                  *
3758 *************************************************/
3759
3760 /* Returns either an unchanged string, or the expanded string in stacking pool
3761 store. Interpreted sequences are:
3762
3763    \...                    normal escaping rules
3764    $name                   substitutes the variable
3765    ${name}                 ditto
3766    ${op:string}            operates on the expanded string value
3767    ${item{arg1}{arg2}...}  expands the args and then does the business
3768                              some literal args are not enclosed in {}
3769
3770 There are now far too many operators and item types to make it worth listing
3771 them here in detail any more.
3772
3773 We use an internal routine recursively to handle embedded substrings. The
3774 external function follows. The yield is NULL if the expansion failed, and there
3775 are two cases: if something collapsed syntactically, or if "fail" was given
3776 as the action on a lookup failure. These can be distinguised by looking at the
3777 variable expand_string_forcedfail, which is TRUE in the latter case.
3778
3779 The skipping flag is set true when expanding a substring that isn't actually
3780 going to be used (after "if" or "lookup") and it prevents lookups from
3781 happening lower down.
3782
3783 Store usage: At start, a store block of the length of the input plus 64
3784 is obtained. This is expanded as necessary by string_cat(), which might have to
3785 get a new block, or might be able to expand the original. At the end of the
3786 function we can release any store above that portion of the yield block that
3787 was actually used. In many cases this will be optimal.
3788
3789 However: if the first item in the expansion is a variable name or header name,
3790 we reset the store before processing it; if the result is in fresh store, we
3791 use that without copying. This is helpful for expanding strings like
3792 $message_headers which can get very long.
3793
3794 There's a problem if a ${dlfunc item has side-effects that cause allocation,
3795 since resetting the store at the end of the expansion will free store that was
3796 allocated by the plugin code as well as the slop after the expanded string. So
3797 we skip any resets if ${dlfunc } has been used. The same applies for ${acl }
3798 and, given the acl condition, ${if }. This is an unfortunate consequence of
3799 string expansion becoming too powerful.
3800
3801 Arguments:
3802   string         the string to be expanded
3803   ket_ends       true if expansion is to stop at }
3804   left           if not NULL, a pointer to the first character after the
3805                  expansion is placed here (typically used with ket_ends)
3806   skipping       TRUE for recursive calls when the value isn't actually going
3807                  to be used (to allow for optimisation)
3808   honour_dollar  TRUE if $ is to be expanded,
3809                  FALSE if it's just another character
3810   resetok_p      if not NULL, pointer to flag - write FALSE if unsafe to reset
3811                  the store.
3812
3813 Returns:         NULL if expansion fails:
3814                    expand_string_forcedfail is set TRUE if failure was forced
3815                    expand_string_message contains a textual error message
3816                  a pointer to the expanded string on success
3817 */
3818
3819 static uschar *
3820 expand_string_internal(const uschar *string, BOOL ket_ends, const uschar **left,
3821   BOOL skipping, BOOL honour_dollar, BOOL *resetok_p)
3822 {
3823 int ptr = 0;
3824 int size = Ustrlen(string)+ 64;
3825 int item_type;
3826 uschar *yield = store_get(size);
3827 const uschar *s = string;
3828 uschar *save_expand_nstring[EXPAND_MAXN+1];
3829 int save_expand_nlength[EXPAND_MAXN+1];
3830 BOOL resetok = TRUE;
3831
3832 expand_string_forcedfail = FALSE;
3833 expand_string_message = US"";
3834
3835 while (*s != 0)
3836   {
3837   uschar *value;
3838   uschar name[256];
3839
3840   /* \ escapes the next character, which must exist, or else
3841   the expansion fails. There's a special escape, \N, which causes
3842   copying of the subject verbatim up to the next \N. Otherwise,
3843   the escapes are the standard set. */
3844
3845   if (*s == '\\')
3846     {
3847     if (s[1] == 0)
3848       {
3849       expand_string_message = US"\\ at end of string";
3850       goto EXPAND_FAILED;
3851       }
3852
3853     if (s[1] == 'N')
3854       {
3855       const uschar * t = s + 2;
3856       for (s = t; *s != 0; s++) if (*s == '\\' && s[1] == 'N') break;
3857       yield = string_cat(yield, &size, &ptr, t, s - t);
3858       if (*s != 0) s += 2;
3859       }
3860
3861     else
3862       {
3863       uschar ch[1];
3864       ch[0] = string_interpret_escape(&s);
3865       s++;
3866       yield = string_cat(yield, &size, &ptr, ch, 1);
3867       }
3868
3869     continue;
3870     }
3871
3872   /*{*/
3873   /* Anything other than $ is just copied verbatim, unless we are
3874   looking for a terminating } character. */
3875
3876   /*{*/
3877   if (ket_ends && *s == '}') break;
3878
3879   if (*s != '$' || !honour_dollar)
3880     {
3881     yield = string_cat(yield, &size, &ptr, s++, 1);
3882     continue;
3883     }
3884
3885   /* No { after the $ - must be a plain name or a number for string
3886   match variable. There has to be a fudge for variables that are the
3887   names of header fields preceded by "$header_" because header field
3888   names can contain any printing characters except space and colon.
3889   For those that don't like typing this much, "$h_" is a synonym for
3890   "$header_". A non-existent header yields a NULL value; nothing is
3891   inserted. */  /*}*/
3892
3893   if (isalpha((*(++s))))
3894     {
3895     int len;
3896     int newsize = 0;
3897
3898     s = read_name(name, sizeof(name), s, US"_");
3899
3900     /* If this is the first thing to be expanded, release the pre-allocated
3901     buffer. */
3902
3903     if (ptr == 0 && yield != NULL)
3904       {
3905       if (resetok) store_reset(yield);
3906       yield = NULL;
3907       size = 0;
3908       }
3909
3910     /* Header */
3911
3912     if (Ustrncmp(name, "h_", 2) == 0 ||
3913         Ustrncmp(name, "rh_", 3) == 0 ||
3914         Ustrncmp(name, "bh_", 3) == 0 ||
3915         Ustrncmp(name, "header_", 7) == 0 ||
3916         Ustrncmp(name, "rheader_", 8) == 0 ||
3917         Ustrncmp(name, "bheader_", 8) == 0)
3918       {
3919       BOOL want_raw = (name[0] == 'r')? TRUE : FALSE;
3920       uschar *charset = (name[0] == 'b')? NULL : headers_charset;
3921       s = read_header_name(name, sizeof(name), s);
3922       value = find_header(name, FALSE, &newsize, want_raw, charset);
3923
3924       /* If we didn't find the header, and the header contains a closing brace
3925       character, this may be a user error where the terminating colon
3926       has been omitted. Set a flag to adjust the error message in this case.
3927       But there is no error here - nothing gets inserted. */
3928
3929       if (value == NULL)
3930         {
3931         if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
3932         continue;
3933         }
3934       }
3935
3936     /* Variable */
3937
3938     else if (!(value = find_variable(name, FALSE, skipping, &newsize)))
3939       {
3940