src/src/expand.c

   1 /* $Cambridge: exim/src/src/expand.c,v 1.91 2007/10/04 13:23:05 tom Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) University of Cambridge 1995 - 2007 */
   8 /* See the file NOTICE for conditions of use and distribution. */
   9
  10
  11 /* Functions for handling string expansion. */
  12
  13
  14 #include "exim.h"
  15
  16 /* Recursively called function */
  17
  18 static uschar *expand_string_internal(uschar *, BOOL, uschar **, BOOL);
  19
  20 #ifdef STAND_ALONE
  21 #ifndef SUPPORT_CRYPTEQ
  22 #define SUPPORT_CRYPTEQ
  23 #endif
  24 #endif
  25
  26 #ifdef LOOKUP_LDAP
  27 #include "lookups/ldap.h"
  28 #endif
  29
  30 #ifdef SUPPORT_CRYPTEQ
  31 #ifdef CRYPT_H
  32 #include <crypt.h>
  33 #endif
  34 #ifndef HAVE_CRYPT16
  35 extern char* crypt16(char*, char*);
  36 #endif
  37 #endif
  38
  39 /* The handling of crypt16() is a mess. I will record below the analysis of the
  40 mess that was sent to me. We decided, however, to make changing this very low
  41 priority, because in practice people are moving away from the crypt()
  42 algorithms nowadays, so it doesn't seem worth it.
  43
  44 <quote>
  45 There is an algorithm named "crypt16" in Ultrix and Tru64.  It crypts
  46 the first 8 characters of the password using a 20-round version of crypt
  47 (standard crypt does 25 rounds).  It then crypts the next 8 characters,
  48 or an empty block if the password is less than 9 characters, using a
  49 20-round version of crypt and the same salt as was used for the first
  50 block.  Charaters after the first 16 are ignored.  It always generates
  51 a 16-byte hash, which is expressed together with the salt as a string
  52 of 24 base 64 digits.  Here are some links to peruse:
  53
  54         http://cvs.pld.org.pl/pam/pamcrypt/crypt16.c?rev=1.2
  55         http://seclists.org/bugtraq/1999/Mar/0076.html
  56
  57 There's a different algorithm named "bigcrypt" in HP-UX, Digital Unix,
  58 and OSF/1.  This is the same as the standard crypt if given a password
  59 of 8 characters or less.  If given more, it first does the same as crypt
  60 using the first 8 characters, then crypts the next 8 (the 9th to 16th)
  61 using as salt the first two base 64 digits from the first hash block.
  62 If the password is more than 16 characters then it crypts the 17th to 24th
  63 characters using as salt the first two base 64 digits from the second hash
  64 block.  And so on: I've seen references to it cutting off the password at
  65 40 characters (5 blocks), 80 (10 blocks), or 128 (16 blocks).  Some links:
  66
  67         http://cvs.pld.org.pl/pam/pamcrypt/bigcrypt.c?rev=1.2
  68         http://seclists.org/bugtraq/1999/Mar/0109.html
  69         http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/HTML/AA-Q0R2D-
  70              TET1_html/sec.c222.html#no_id_208
  71
  72 Exim has something it calls "crypt16".  It will either use a native
  73 crypt16 or its own implementation.  A native crypt16 will presumably
  74 be the one that I called "crypt16" above.  The internal "crypt16"
  75 function, however, is a two-block-maximum implementation of what I called
  76 "bigcrypt".  The documentation matches the internal code.
  77
  78 I suspect that whoever did the "crypt16" stuff for Exim didn't realise
  79 that crypt16 and bigcrypt were different things.
  80
  81 Exim uses the LDAP-style scheme identifier "{crypt16}" to refer
  82 to whatever it is using under that name.  This unfortunately sets a
  83 precedent for using "{crypt16}" to identify two incompatible algorithms
  84 whose output can't be distinguished.  With "{crypt16}" thus rendered
  85 ambiguous, I suggest you deprecate it and invent two new identifiers
  86 for the two algorithms.
  87
  88 Both crypt16 and bigcrypt are very poor algorithms, btw.  Hashing parts
  89 of the password separately means they can be cracked separately, so
  90 the double-length hash only doubles the cracking effort instead of
  91 squaring it.  I recommend salted SHA-1 ({SSHA}), or the Blowfish-based
  92 bcrypt ({CRYPT}$2a$).
  93 </quote>
  94 */
  95
  96
  97
  98
  99 /*************************************************
 100 *            Local statics and tables            *
 101 *************************************************/
 102
 103 /* Table of item names, and corresponding switch numbers. The names must be in
 104 alphabetical order. */
 105
 106 static uschar *item_table[] = {
 107   US"dlfunc",
 108   US"extract",
 109   US"filter",
 110   US"hash",
 111   US"hmac",
 112   US"if",
 113   US"length",
 114   US"lookup",
 115   US"map",
 116   US"nhash",
 117   US"perl",
 118   US"prvs",
 119   US"prvscheck",
 120   US"readfile",
 121   US"readsocket",
 122   US"reduce",
 123   US"run",
 124   US"sg",
 125   US"substr",
 126   US"tr" };
 127
 128 enum {
 129   EITEM_DLFUNC,
 130   EITEM_EXTRACT,
 131   EITEM_FILTER,
 132   EITEM_HASH,
 133   EITEM_HMAC,
 134   EITEM_IF,
 135   EITEM_LENGTH,
 136   EITEM_LOOKUP,
 137   EITEM_MAP,
 138   EITEM_NHASH,
 139   EITEM_PERL,
 140   EITEM_PRVS,
 141   EITEM_PRVSCHECK,
 142   EITEM_READFILE,
 143   EITEM_READSOCK,
 144   EITEM_REDUCE,
 145   EITEM_RUN,
 146   EITEM_SG,
 147   EITEM_SUBSTR,
 148   EITEM_TR };
 149
 150 /* Tables of operator names, and corresponding switch numbers. The names must be
 151 in alphabetical order. There are two tables, because underscore is used in some
 152 cases to introduce arguments, whereas for other it is part of the name. This is
 153 an historical mis-design. */
 154
 155 static uschar *op_table_underscore[] = {
 156   US"from_utf8",
 157   US"local_part",
 158   US"quote_local_part",
 159   US"time_eval",
 160   US"time_interval"};
 161
 162 enum {
 163   EOP_FROM_UTF8,
 164   EOP_LOCAL_PART,
 165   EOP_QUOTE_LOCAL_PART,
 166   EOP_TIME_EVAL,
 167   EOP_TIME_INTERVAL };
 168
 169 static uschar *op_table_main[] = {
 170   US"address",
 171   US"addresses",
 172   US"base62",
 173   US"base62d",
 174   US"domain",
 175   US"escape",
 176   US"eval",
 177   US"eval10",
 178   US"expand",
 179   US"h",
 180   US"hash",
 181   US"hex2b64",
 182   US"l",
 183   US"lc",
 184   US"length",
 185   US"mask",
 186   US"md5",
 187   US"nh",
 188   US"nhash",
 189   US"quote",
 190   US"rfc2047",
 191   US"rfc2047d",
 192   US"rxquote",
 193   US"s",
 194   US"sha1",
 195   US"stat",
 196   US"str2b64",
 197   US"strlen",
 198   US"substr",
 199   US"uc" };
 200
 201 enum {
 202   EOP_ADDRESS =  sizeof(op_table_underscore)/sizeof(uschar *),
 203   EOP_ADDRESSES,
 204   EOP_BASE62,
 205   EOP_BASE62D,
 206   EOP_DOMAIN,
 207   EOP_ESCAPE,
 208   EOP_EVAL,
 209   EOP_EVAL10,
 210   EOP_EXPAND,
 211   EOP_H,
 212   EOP_HASH,
 213   EOP_HEX2B64,
 214   EOP_L,
 215   EOP_LC,
 216   EOP_LENGTH,
 217   EOP_MASK,
 218   EOP_MD5,
 219   EOP_NH,
 220   EOP_NHASH,
 221   EOP_QUOTE,
 222   EOP_RFC2047,
 223   EOP_RFC2047D,
 224   EOP_RXQUOTE,
 225   EOP_S,
 226   EOP_SHA1,
 227   EOP_STAT,
 228   EOP_STR2B64,
 229   EOP_STRLEN,
 230   EOP_SUBSTR,
 231   EOP_UC };
 232
 233
 234 /* Table of condition names, and corresponding switch numbers. The names must
 235 be in alphabetical order. */
 236
 237 static uschar *cond_table[] = {
 238   US"<",
 239   US"<=",
 240   US"=",
 241   US"==",     /* Backward compatibility */
 242   US">",
 243   US">=",
 244   US"and",
 245   US"crypteq",
 246   US"def",
 247   US"eq",
 248   US"eqi",
 249   US"exists",
 250   US"first_delivery",
 251   US"forall",
 252   US"forany",
 253   US"ge",
 254   US"gei",
 255   US"gt",
 256   US"gti",
 257   US"isip",
 258   US"isip4",
 259   US"isip6",
 260   US"ldapauth",
 261   US"le",
 262   US"lei",
 263   US"lt",
 264   US"lti",
 265   US"match",
 266   US"match_address",
 267   US"match_domain",
 268   US"match_ip",
 269   US"match_local_part",
 270   US"or",
 271   US"pam",
 272   US"pwcheck",
 273   US"queue_running",
 274   US"radius",
 275   US"saslauthd"
 276 };
 277
 278 enum {
 279   ECOND_NUM_L,
 280   ECOND_NUM_LE,
 281   ECOND_NUM_E,
 282   ECOND_NUM_EE,
 283   ECOND_NUM_G,
 284   ECOND_NUM_GE,
 285   ECOND_AND,
 286   ECOND_CRYPTEQ,
 287   ECOND_DEF,
 288   ECOND_STR_EQ,
 289   ECOND_STR_EQI,
 290   ECOND_EXISTS,
 291   ECOND_FIRST_DELIVERY,
 292   ECOND_FORALL,
 293   ECOND_FORANY,
 294   ECOND_STR_GE,
 295   ECOND_STR_GEI,
 296   ECOND_STR_GT,
 297   ECOND_STR_GTI,
 298   ECOND_ISIP,
 299   ECOND_ISIP4,
 300   ECOND_ISIP6,
 301   ECOND_LDAPAUTH,
 302   ECOND_STR_LE,
 303   ECOND_STR_LEI,
 304   ECOND_STR_LT,
 305   ECOND_STR_LTI,
 306   ECOND_MATCH,
 307   ECOND_MATCH_ADDRESS,
 308   ECOND_MATCH_DOMAIN,
 309   ECOND_MATCH_IP,
 310   ECOND_MATCH_LOCAL_PART,
 311   ECOND_OR,
 312   ECOND_PAM,
 313   ECOND_PWCHECK,
 314   ECOND_QUEUE_RUNNING,
 315   ECOND_RADIUS,
 316   ECOND_SASLAUTHD
 317 };
 318
 319
 320 /* Type for main variable table */
 321
 322 typedef struct {
 323   char *name;
 324   int   type;
 325   void *value;
 326 } var_entry;
 327
 328 /* Type for entries pointing to address/length pairs. Not currently
 329 in use. */
 330
 331 typedef struct {
 332   uschar **address;
 333   int  *length;
 334 } alblock;
 335
 336 /* Types of table entry */
 337
 338 enum {
 339   vtype_int,            /* value is address of int */
 340   vtype_filter_int,     /* ditto, but recognized only when filtering */
 341   vtype_ino,            /* value is address of ino_t (not always an int) */
 342   vtype_uid,            /* value is address of uid_t (not always an int) */
 343   vtype_gid,            /* value is address of gid_t (not always an int) */
 344   vtype_stringptr,      /* value is address of pointer to string */
 345   vtype_msgbody,        /* as stringptr, but read when first required */
 346   vtype_msgbody_end,    /* ditto, the end of the message */
 347   vtype_msgheaders,     /* the message's headers, processed */
 348   vtype_msgheaders_raw, /* the message's headers, unprocessed */
 349   vtype_localpart,      /* extract local part from string */
 350   vtype_domain,         /* extract domain from string */
 351   vtype_recipients,     /* extract recipients from recipients list */
 352                         /* (available only in system filters, ACLs, and */
 353                         /* local_scan()) */
 354   vtype_todbsdin,       /* value not used; generate BSD inbox tod */
 355   vtype_tode,           /* value not used; generate tod in epoch format */
 356   vtype_todf,           /* value not used; generate full tod */
 357   vtype_todl,           /* value not used; generate log tod */
 358   vtype_todlf,          /* value not used; generate log file datestamp tod */
 359   vtype_todzone,        /* value not used; generate time zone only */
 360   vtype_todzulu,        /* value not used; generate zulu tod */
 361   vtype_reply,          /* value not used; get reply from headers */
 362   vtype_pid,            /* value not used; result is pid */
 363   vtype_host_lookup,    /* value not used; get host name */
 364   vtype_load_avg,       /* value not used; result is int from os_getloadavg */
 365   vtype_pspace,         /* partition space; value is T/F for spool/log */
 366   vtype_pinodes         /* partition inodes; value is T/F for spool/log */
 367 #ifdef EXPERIMENTAL_DOMAINKEYS
 368  ,vtype_dk_verify       /* Serve request out of DomainKeys verification structure */
 369 #endif
 370   };
 371
 372 /* This table must be kept in alphabetical order. */
 373
 374 static var_entry var_table[] = {
 375   /* WARNING: Do not invent variables whose names start acl_c or acl_m because
 376      they will be confused with user-creatable ACL variables. */
 377   { "acl_verify_message",  vtype_stringptr,   &acl_verify_message },
 378   { "address_data",        vtype_stringptr,   &deliver_address_data },
 379   { "address_file",        vtype_stringptr,   &address_file },
 380   { "address_pipe",        vtype_stringptr,   &address_pipe },
 381   { "authenticated_id",    vtype_stringptr,   &authenticated_id },
 382   { "authenticated_sender",vtype_stringptr,   &authenticated_sender },
 383   { "authentication_failed",vtype_int,        &authentication_failed },
 384 #ifdef EXPERIMENTAL_BRIGHTMAIL
 385   { "bmi_alt_location",    vtype_stringptr,   &bmi_alt_location },
 386   { "bmi_base64_tracker_verdict", vtype_stringptr, &bmi_base64_tracker_verdict },
 387   { "bmi_base64_verdict",  vtype_stringptr,   &bmi_base64_verdict },
 388   { "bmi_deliver",         vtype_int,         &bmi_deliver },
 389 #endif
 390   { "body_linecount",      vtype_int,         &body_linecount },
 391   { "body_zerocount",      vtype_int,         &body_zerocount },
 392   { "bounce_recipient",    vtype_stringptr,   &bounce_recipient },
 393   { "bounce_return_size_limit", vtype_int,    &bounce_return_size_limit },
 394   { "caller_gid",          vtype_gid,         &real_gid },
 395   { "caller_uid",          vtype_uid,         &real_uid },
 396   { "compile_date",        vtype_stringptr,   &version_date },
 397   { "compile_number",      vtype_stringptr,   &version_cnumber },
 398   { "csa_status",          vtype_stringptr,   &csa_status },
 399 #ifdef WITH_OLD_DEMIME
 400   { "demime_errorlevel",   vtype_int,         &demime_errorlevel },
 401   { "demime_reason",       vtype_stringptr,   &demime_reason },
 402 #endif
 403 #ifdef EXPERIMENTAL_DOMAINKEYS
 404   { "dk_domain",           vtype_stringptr,   &dk_signing_domain },
 405   { "dk_is_signed",        vtype_dk_verify,   NULL },
 406   { "dk_result",           vtype_dk_verify,   NULL },
 407   { "dk_selector",         vtype_stringptr,   &dk_signing_selector },
 408   { "dk_sender",           vtype_dk_verify,   NULL },
 409   { "dk_sender_domain",    vtype_dk_verify,   NULL },
 410   { "dk_sender_local_part",vtype_dk_verify,   NULL },
 411   { "dk_sender_source",    vtype_dk_verify,   NULL },
 412   { "dk_signsall",         vtype_dk_verify,   NULL },
 413   { "dk_status",           vtype_dk_verify,   NULL },
 414   { "dk_testing",          vtype_dk_verify,   NULL },
 415 #endif
 416 #ifdef EXPERIMENTAL_DKIM
 417   { "dkim_domain",         vtype_stringptr,   &dkim_signing_domain },
 418   { "dkim_selector",       vtype_stringptr,   &dkim_signing_selector },
 419 #endif
 420   { "dnslist_domain",      vtype_stringptr,   &dnslist_domain },
 421   { "dnslist_matched",     vtype_stringptr,   &dnslist_matched },
 422   { "dnslist_text",        vtype_stringptr,   &dnslist_text },
 423   { "dnslist_value",       vtype_stringptr,   &dnslist_value },
 424   { "domain",              vtype_stringptr,   &deliver_domain },
 425   { "domain_data",         vtype_stringptr,   &deliver_domain_data },
 426   { "exim_gid",            vtype_gid,         &exim_gid },
 427   { "exim_path",           vtype_stringptr,   &exim_path },
 428   { "exim_uid",            vtype_uid,         &exim_uid },
 429 #ifdef WITH_OLD_DEMIME
 430   { "found_extension",     vtype_stringptr,   &found_extension },
 431 #endif
 432   { "home",                vtype_stringptr,   &deliver_home },
 433   { "host",                vtype_stringptr,   &deliver_host },
 434   { "host_address",        vtype_stringptr,   &deliver_host_address },
 435   { "host_data",           vtype_stringptr,   &host_data },
 436   { "host_lookup_deferred",vtype_int,         &host_lookup_deferred },
 437   { "host_lookup_failed",  vtype_int,         &host_lookup_failed },
 438   { "inode",               vtype_ino,         &deliver_inode },
 439   { "interface_address",   vtype_stringptr,   &interface_address },
 440   { "interface_port",      vtype_int,         &interface_port },
 441   { "item",                vtype_stringptr,   &iterate_item },
 442   #ifdef LOOKUP_LDAP
 443   { "ldap_dn",             vtype_stringptr,   &eldap_dn },
 444   #endif
 445   { "load_average",        vtype_load_avg,    NULL },
 446   { "local_part",          vtype_stringptr,   &deliver_localpart },
 447   { "local_part_data",     vtype_stringptr,   &deliver_localpart_data },
 448   { "local_part_prefix",   vtype_stringptr,   &deliver_localpart_prefix },
 449   { "local_part_suffix",   vtype_stringptr,   &deliver_localpart_suffix },
 450   { "local_scan_data",     vtype_stringptr,   &local_scan_data },
 451   { "local_user_gid",      vtype_gid,         &local_user_gid },
 452   { "local_user_uid",      vtype_uid,         &local_user_uid },
 453   { "localhost_number",    vtype_int,         &host_number },
 454   { "log_inodes",          vtype_pinodes,     (void *)FALSE },
 455   { "log_space",           vtype_pspace,      (void *)FALSE },
 456   { "mailstore_basename",  vtype_stringptr,   &mailstore_basename },
 457 #ifdef WITH_CONTENT_SCAN
 458   { "malware_name",        vtype_stringptr,   &malware_name },
 459 #endif
 460   { "max_received_linelength", vtype_int,     &max_received_linelength },
 461   { "message_age",         vtype_int,         &message_age },
 462   { "message_body",        vtype_msgbody,     &message_body },
 463   { "message_body_end",    vtype_msgbody_end, &message_body_end },
 464   { "message_body_size",   vtype_int,         &message_body_size },
 465   { "message_exim_id",     vtype_stringptr,   &message_id },
 466   { "message_headers",     vtype_msgheaders,  NULL },
 467   { "message_headers_raw", vtype_msgheaders_raw, NULL },
 468   { "message_id",          vtype_stringptr,   &message_id },
 469   { "message_linecount",   vtype_int,         &message_linecount },
 470   { "message_size",        vtype_int,         &message_size },
 471 #ifdef WITH_CONTENT_SCAN
 472   { "mime_anomaly_level",  vtype_int,         &mime_anomaly_level },
 473   { "mime_anomaly_text",   vtype_stringptr,   &mime_anomaly_text },
 474   { "mime_boundary",       vtype_stringptr,   &mime_boundary },
 475   { "mime_charset",        vtype_stringptr,   &mime_charset },
 476   { "mime_content_description", vtype_stringptr, &mime_content_description },
 477   { "mime_content_disposition", vtype_stringptr, &mime_content_disposition },
 478   { "mime_content_id",     vtype_stringptr,   &mime_content_id },
 479   { "mime_content_size",   vtype_int,         &mime_content_size },
 480   { "mime_content_transfer_encoding",vtype_stringptr, &mime_content_transfer_encoding },
 481   { "mime_content_type",   vtype_stringptr,   &mime_content_type },
 482   { "mime_decoded_filename", vtype_stringptr, &mime_decoded_filename },
 483   { "mime_filename",       vtype_stringptr,   &mime_filename },
 484   { "mime_is_coverletter", vtype_int,         &mime_is_coverletter },
 485   { "mime_is_multipart",   vtype_int,         &mime_is_multipart },
 486   { "mime_is_rfc822",      vtype_int,         &mime_is_rfc822 },
 487   { "mime_part_count",     vtype_int,         &mime_part_count },
 488 #endif
 489   { "n0",                  vtype_filter_int,  &filter_n[0] },
 490   { "n1",                  vtype_filter_int,  &filter_n[1] },
 491   { "n2",                  vtype_filter_int,  &filter_n[2] },
 492   { "n3",                  vtype_filter_int,  &filter_n[3] },
 493   { "n4",                  vtype_filter_int,  &filter_n[4] },
 494   { "n5",                  vtype_filter_int,  &filter_n[5] },
 495   { "n6",                  vtype_filter_int,  &filter_n[6] },
 496   { "n7",                  vtype_filter_int,  &filter_n[7] },
 497   { "n8",                  vtype_filter_int,  &filter_n[8] },
 498   { "n9",                  vtype_filter_int,  &filter_n[9] },
 499   { "original_domain",     vtype_stringptr,   &deliver_domain_orig },
 500   { "original_local_part", vtype_stringptr,   &deliver_localpart_orig },
 501   { "originator_gid",      vtype_gid,         &originator_gid },
 502   { "originator_uid",      vtype_uid,         &originator_uid },
 503   { "parent_domain",       vtype_stringptr,   &deliver_domain_parent },
 504   { "parent_local_part",   vtype_stringptr,   &deliver_localpart_parent },
 505   { "pid",                 vtype_pid,         NULL },
 506   { "primary_hostname",    vtype_stringptr,   &primary_hostname },
 507   { "prvscheck_address",   vtype_stringptr,   &prvscheck_address },
 508   { "prvscheck_keynum",    vtype_stringptr,   &prvscheck_keynum },
 509   { "prvscheck_result",    vtype_stringptr,   &prvscheck_result },
 510   { "qualify_domain",      vtype_stringptr,   &qualify_domain_sender },
 511   { "qualify_recipient",   vtype_stringptr,   &qualify_domain_recipient },
 512   { "rcpt_count",          vtype_int,         &rcpt_count },
 513   { "rcpt_defer_count",    vtype_int,         &rcpt_defer_count },
 514   { "rcpt_fail_count",     vtype_int,         &rcpt_fail_count },
 515   { "received_count",      vtype_int,         &received_count },
 516   { "received_for",        vtype_stringptr,   &received_for },
 517   { "received_ip_address", vtype_stringptr,   &interface_address },
 518   { "received_port",       vtype_int,         &interface_port },
 519   { "received_protocol",   vtype_stringptr,   &received_protocol },
 520   { "received_time",       vtype_int,         &received_time },
 521   { "recipient_data",      vtype_stringptr,   &recipient_data },
 522   { "recipient_verify_failure",vtype_stringptr,&recipient_verify_failure },
 523   { "recipients",          vtype_recipients,  NULL },
 524   { "recipients_count",    vtype_int,         &recipients_count },
 525 #ifdef WITH_CONTENT_SCAN
 526   { "regex_match_string",  vtype_stringptr,   &regex_match_string },
 527 #endif
 528   { "reply_address",       vtype_reply,       NULL },
 529   { "return_path",         vtype_stringptr,   &return_path },
 530   { "return_size_limit",   vtype_int,         &bounce_return_size_limit },
 531   { "runrc",               vtype_int,         &runrc },
 532   { "self_hostname",       vtype_stringptr,   &self_hostname },
 533   { "sender_address",      vtype_stringptr,   &sender_address },
 534   { "sender_address_data", vtype_stringptr,   &sender_address_data },
 535   { "sender_address_domain", vtype_domain,    &sender_address },
 536   { "sender_address_local_part", vtype_localpart, &sender_address },
 537   { "sender_data",         vtype_stringptr,   &sender_data },
 538   { "sender_fullhost",     vtype_stringptr,   &sender_fullhost },
 539   { "sender_helo_name",    vtype_stringptr,   &sender_helo_name },
 540   { "sender_host_address", vtype_stringptr,   &sender_host_address },
 541   { "sender_host_authenticated",vtype_stringptr, &sender_host_authenticated },
 542   { "sender_host_name",    vtype_host_lookup, NULL },
 543   { "sender_host_port",    vtype_int,         &sender_host_port },
 544   { "sender_ident",        vtype_stringptr,   &sender_ident },
 545   { "sender_rate",         vtype_stringptr,   &sender_rate },
 546   { "sender_rate_limit",   vtype_stringptr,   &sender_rate_limit },
 547   { "sender_rate_period",  vtype_stringptr,   &sender_rate_period },
 548   { "sender_rcvhost",      vtype_stringptr,   &sender_rcvhost },
 549   { "sender_verify_failure",vtype_stringptr,  &sender_verify_failure },
 550   { "sending_ip_address",  vtype_stringptr,   &sending_ip_address },
 551   { "sending_port",        vtype_int,         &sending_port },
 552   { "smtp_active_hostname", vtype_stringptr,  &smtp_active_hostname },
 553   { "smtp_command",        vtype_stringptr,   &smtp_cmd_buffer },
 554   { "smtp_command_argument", vtype_stringptr, &smtp_cmd_argument },
 555   { "smtp_count_at_connection_start", vtype_int, &smtp_accept_count },
 556   { "smtp_notquit_reason", vtype_stringptr,   &smtp_notquit_reason },
 557   { "sn0",                 vtype_filter_int,  &filter_sn[0] },
 558   { "sn1",                 vtype_filter_int,  &filter_sn[1] },
 559   { "sn2",                 vtype_filter_int,  &filter_sn[2] },
 560   { "sn3",                 vtype_filter_int,  &filter_sn[3] },
 561   { "sn4",                 vtype_filter_int,  &filter_sn[4] },
 562   { "sn5",                 vtype_filter_int,  &filter_sn[5] },
 563   { "sn6",                 vtype_filter_int,  &filter_sn[6] },
 564   { "sn7",                 vtype_filter_int,  &filter_sn[7] },
 565   { "sn8",                 vtype_filter_int,  &filter_sn[8] },
 566   { "sn9",                 vtype_filter_int,  &filter_sn[9] },
 567 #ifdef WITH_CONTENT_SCAN
 568   { "spam_bar",            vtype_stringptr,   &spam_bar },
 569   { "spam_report",         vtype_stringptr,   &spam_report },
 570   { "spam_score",          vtype_stringptr,   &spam_score },
 571   { "spam_score_int",      vtype_stringptr,   &spam_score_int },
 572 #endif
 573 #ifdef EXPERIMENTAL_SPF
 574   { "spf_header_comment",  vtype_stringptr,   &spf_header_comment },
 575   { "spf_received",        vtype_stringptr,   &spf_received },
 576   { "spf_result",          vtype_stringptr,   &spf_result },
 577   { "spf_smtp_comment",    vtype_stringptr,   &spf_smtp_comment },
 578 #endif
 579   { "spool_directory",     vtype_stringptr,   &spool_directory },
 580   { "spool_inodes",        vtype_pinodes,     (void *)TRUE },
 581   { "spool_space",         vtype_pspace,      (void *)TRUE },
 582 #ifdef EXPERIMENTAL_SRS
 583   { "srs_db_address",      vtype_stringptr,   &srs_db_address },
 584   { "srs_db_key",          vtype_stringptr,   &srs_db_key },
 585   { "srs_orig_recipient",  vtype_stringptr,   &srs_orig_recipient },
 586   { "srs_orig_sender",     vtype_stringptr,   &srs_orig_sender },
 587   { "srs_recipient",       vtype_stringptr,   &srs_recipient },
 588   { "srs_status",          vtype_stringptr,   &srs_status },
 589 #endif
 590   { "thisaddress",         vtype_stringptr,   &filter_thisaddress },
 591   { "tls_certificate_verified", vtype_int,    &tls_certificate_verified },
 592   { "tls_cipher",          vtype_stringptr,   &tls_cipher },
 593   { "tls_peerdn",          vtype_stringptr,   &tls_peerdn },
 594   { "tod_bsdinbox",        vtype_todbsdin,    NULL },
 595   { "tod_epoch",           vtype_tode,        NULL },
 596   { "tod_full",            vtype_todf,        NULL },
 597   { "tod_log",             vtype_todl,        NULL },
 598   { "tod_logfile",         vtype_todlf,       NULL },
 599   { "tod_zone",            vtype_todzone,     NULL },
 600   { "tod_zulu",            vtype_todzulu,     NULL },
 601   { "value",               vtype_stringptr,   &lookup_value },
 602   { "version_number",      vtype_stringptr,   &version_string },
 603   { "warn_message_delay",  vtype_stringptr,   &warnmsg_delay },
 604   { "warn_message_recipient",vtype_stringptr, &warnmsg_recipients },
 605   { "warn_message_recipients",vtype_stringptr,&warnmsg_recipients },
 606   { "warnmsg_delay",       vtype_stringptr,   &warnmsg_delay },
 607   { "warnmsg_recipient",   vtype_stringptr,   &warnmsg_recipients },
 608   { "warnmsg_recipients",  vtype_stringptr,   &warnmsg_recipients }
 609 };
 610
 611 static int var_table_size = sizeof(var_table)/sizeof(var_entry);
 612 static uschar var_buffer[256];
 613 static BOOL malformed_header;
 614
 615 /* For textual hashes */
 616
 617 static char *hashcodes = "abcdefghijklmnopqrtsuvwxyz"
 618                          "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 619                          "0123456789";
 620
 621 enum { HMAC_MD5, HMAC_SHA1 };
 622
 623 /* For numeric hashes */
 624
 625 static unsigned int prime[] = {
 626   2,   3,   5,   7,  11,  13,  17,  19,  23,  29,
 627  31,  37,  41,  43,  47,  53,  59,  61,  67,  71,
 628  73,  79,  83,  89,  97, 101, 103, 107, 109, 113};
 629
 630 /* For printing modes in symbolic form */
 631
 632 static uschar *mtable_normal[] =
 633   { US"---", US"--x", US"-w-", US"-wx", US"r--", US"r-x", US"rw-", US"rwx" };
 634
 635 static uschar *mtable_setid[] =
 636   { US"--S", US"--s", US"-wS", US"-ws", US"r-S", US"r-s", US"rwS", US"rws" };
 637
 638 static uschar *mtable_sticky[] =
 639   { US"--T", US"--t", US"-wT", US"-wt", US"r-T", US"r-t", US"rwT", US"rwt" };
 640
 641
 642
 643 /*************************************************
 644 *           Tables for UTF-8 support             *
 645 *************************************************/
 646
 647 /* Table of the number of extra characters, indexed by the first character
 648 masked with 0x3f. The highest number for a valid UTF-8 character is in fact
 649 0x3d. */
 650
 651 static uschar utf8_table1[] = {
 652   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 653   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
 654   2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
 655   3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5 };
 656
 657 /* These are the masks for the data bits in the first byte of a character,
 658 indexed by the number of additional bytes. */
 659
 660 static int utf8_table2[] = { 0xff, 0x1f, 0x0f, 0x07, 0x03, 0x01};
 661
 662 /* Get the next UTF-8 character, advancing the pointer. */
 663
 664 #define GETUTF8INC(c, ptr) \
 665   c = *ptr++; \
 666   if ((c & 0xc0) == 0xc0) \
 667     { \
 668     int a = utf8_table1[c & 0x3f];  /* Number of additional bytes */ \
 669     int s = 6*a; \
 670     c = (c & utf8_table2[a]) << s; \
 671     while (a-- > 0) \
 672       { \
 673       s -= 6; \
 674       c |= (*ptr++ & 0x3f) << s; \
 675       } \
 676     }
 677
 678
 679 /*************************************************
 680 *           Binary chop search on a table        *
 681 *************************************************/
 682
 683 /* This is used for matching expansion items and operators.
 684
 685 Arguments:
 686   name        the name that is being sought
 687   table       the table to search
 688   table_size  the number of items in the table
 689
 690 Returns:      the offset in the table, or -1
 691 */
 692
 693 static int
 694 chop_match(uschar *name, uschar **table, int table_size)
 695 {
 696 uschar **bot = table;
 697 uschar **top = table + table_size;
 698
 699 while (top > bot)
 700   {
 701   uschar **mid = bot + (top - bot)/2;
 702   int c = Ustrcmp(name, *mid);
 703   if (c == 0) return mid - table;
 704   if (c > 0) bot = mid + 1; else top = mid;
 705   }
 706
 707 return -1;
 708 }
 709
 710
 711
 712 /*************************************************
 713 *          Check a condition string              *
 714 *************************************************/
 715
 716 /* This function is called to expand a string, and test the result for a "true"
 717 or "false" value. Failure of the expansion yields FALSE; logged unless it was a
 718 forced fail or lookup defer. All store used by the function can be released on
 719 exit.
 720
 721 Arguments:
 722   condition     the condition string
 723   m1            text to be incorporated in panic error
 724   m2            ditto
 725
 726 Returns:        TRUE if condition is met, FALSE if not
 727 */
 728
 729 BOOL
 730 expand_check_condition(uschar *condition, uschar *m1, uschar *m2)
 731 {
 732 int rc;
 733 void *reset_point = store_get(0);
 734 uschar *ss = expand_string(condition);
 735 if (ss == NULL)
 736   {
 737   if (!expand_string_forcedfail && !search_find_defer)
 738     log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand condition \"%s\" "
 739       "for %s %s: %s", condition, m1, m2, expand_string_message);
 740   return FALSE;
 741   }
 742 rc = ss[0] != 0 && Ustrcmp(ss, "0") != 0 && strcmpic(ss, US"no") != 0 &&
 743   strcmpic(ss, US"false") != 0;
 744 store_reset(reset_point);
 745 return rc;
 746 }
 747
 748
 749
 750 /*************************************************
 751 *             Pick out a name from a string      *
 752 *************************************************/
 753
 754 /* If the name is too long, it is silently truncated.
 755
 756 Arguments:
 757   name      points to a buffer into which to put the name
 758   max       is the length of the buffer
 759   s         points to the first alphabetic character of the name
 760   extras    chars other than alphanumerics to permit
 761
 762 Returns:    pointer to the first character after the name
 763
 764 Note: The test for *s != 0 in the while loop is necessary because
 765 Ustrchr() yields non-NULL if the character is zero (which is not something
 766 I expected). */
 767
 768 static uschar *
 769 read_name(uschar *name, int max, uschar *s, uschar *extras)
 770 {
 771 int ptr = 0;
 772 while (*s != 0 && (isalnum(*s) || Ustrchr(extras, *s) != NULL))
 773   {
 774   if (ptr < max-1) name[ptr++] = *s;
 775   s++;
 776   }
 777 name[ptr] = 0;
 778 return s;
 779 }
 780
 781
 782
 783 /*************************************************
 784 *     Pick out the rest of a header name         *
 785 *************************************************/
 786
 787 /* A variable name starting $header_ (or just $h_ for those who like
 788 abbreviations) might not be the complete header name because headers can
 789 contain any printing characters in their names, except ':'. This function is
 790 called to read the rest of the name, chop h[eader]_ off the front, and put ':'
 791 on the end, if the name was terminated by white space.
 792
 793 Arguments:
 794   name      points to a buffer in which the name read so far exists
 795   max       is the length of the buffer
 796   s         points to the first character after the name so far, i.e. the
 797             first non-alphameric character after $header_xxxxx
 798
 799 Returns:    a pointer to the first character after the header name
 800 */
 801
 802 static uschar *
 803 read_header_name(uschar *name, int max, uschar *s)
 804 {
 805 int prelen = Ustrchr(name, '_') - name + 1;
 806 int ptr = Ustrlen(name) - prelen;
 807 if (ptr > 0) memmove(name, name+prelen, ptr);
 808 while (mac_isgraph(*s) && *s != ':')
 809   {
 810   if (ptr < max-1) name[ptr++] = *s;
 811   s++;
 812   }
 813 if (*s == ':') s++;
 814 name[ptr++] = ':';
 815 name[ptr] = 0;
 816 return s;
 817 }
 818
 819
 820
 821 /*************************************************
 822 *           Pick out a number from a string      *
 823 *************************************************/
 824
 825 /* Arguments:
 826   n     points to an integer into which to put the number
 827   s     points to the first digit of the number
 828
 829 Returns:  a pointer to the character after the last digit
 830 */
 831
 832 static uschar *
 833 read_number(int *n, uschar *s)
 834 {
 835 *n = 0;
 836 while (isdigit(*s)) *n = *n * 10 + (*s++ - '0');
 837 return s;
 838 }
 839
 840
 841
 842 /*************************************************
 843 *        Extract keyed subfield from a string    *
 844 *************************************************/
 845
 846 /* The yield is in dynamic store; NULL means that the key was not found.
 847
 848 Arguments:
 849   key       points to the name of the key
 850   s         points to the string from which to extract the subfield
 851
 852 Returns:    NULL if the subfield was not found, or
 853             a pointer to the subfield's data
 854 */
 855
 856 static uschar *
 857 expand_getkeyed(uschar *key, uschar *s)
 858 {
 859 int length = Ustrlen(key);
 860 while (isspace(*s)) s++;
 861
 862 /* Loop to search for the key */
 863
 864 while (*s != 0)
 865   {
 866   int dkeylength;
 867   uschar *data;
 868   uschar *dkey = s;
 869
 870   while (*s != 0 && *s != '=' && !isspace(*s)) s++;
 871   dkeylength = s - dkey;
 872   while (isspace(*s)) s++;
 873   if (*s == '=') while (isspace((*(++s))));
 874
 875   data = string_dequote(&s);
 876   if (length == dkeylength && strncmpic(key, dkey, length) == 0)
 877     return data;
 878
 879   while (isspace(*s)) s++;
 880   }
 881
 882 return NULL;
 883 }
 884
 885
 886
 887
 888 /*************************************************
 889 *   Extract numbered subfield from string        *
 890 *************************************************/
 891
 892 /* Extracts a numbered field from a string that is divided by tokens - for
 893 example a line from /etc/passwd is divided by colon characters.  First field is
 894 numbered one.  Negative arguments count from the right. Zero returns the whole
 895 string. Returns NULL if there are insufficient tokens in the string
 896
 897 ***WARNING***
 898 Modifies final argument - this is a dynamically generated string, so that's OK.
 899
 900 Arguments:
 901   field       number of field to be extracted,
 902                 first field = 1, whole string = 0, last field = -1
 903   separators  characters that are used to break string into tokens
 904   s           points to the string from which to extract the subfield
 905
 906 Returns:      NULL if the field was not found,
 907               a pointer to the field's data inside s (modified to add 0)
 908 */
 909
 910 static uschar *
 911 expand_gettokened (int field, uschar *separators, uschar *s)
 912 {
 913 int sep = 1;
 914 int count;
 915 uschar *ss = s;
 916 uschar *fieldtext = NULL;
 917
 918 if (field == 0) return s;
 919
 920 /* Break the line up into fields in place; for field > 0 we stop when we have
 921 done the number of fields we want. For field < 0 we continue till the end of
 922 the string, counting the number of fields. */
 923
 924 count = (field > 0)? field : INT_MAX;
 925
 926 while (count-- > 0)
 927   {
 928   size_t len;
 929
 930   /* Previous field was the last one in the string. For a positive field
 931   number, this means there are not enough fields. For a negative field number,
 932   check that there are enough, and scan back to find the one that is wanted. */
 933
 934   if (sep == 0)
 935     {
 936     if (field > 0 || (-field) > (INT_MAX - count - 1)) return NULL;
 937     if ((-field) == (INT_MAX - count - 1)) return s;
 938     while (field++ < 0)
 939       {
 940       ss--;
 941       while (ss[-1] != 0) ss--;
 942       }
 943     fieldtext = ss;
 944     break;
 945     }
 946
 947   /* Previous field was not last in the string; save its start and put a
 948   zero at its end. */
 949
 950   fieldtext = ss;
 951   len = Ustrcspn(ss, separators);
 952   sep = ss[len];
 953   ss[len] = 0;
 954   ss += len + 1;
 955   }
 956
 957 return fieldtext;
 958 }
 959
 960
 961
 962 /*************************************************
 963 *        Extract a substring from a string       *
 964 *************************************************/
 965
 966 /* Perform the ${substr or ${length expansion operations.
 967
 968 Arguments:
 969   subject     the input string
 970   value1      the offset from the start of the input string to the start of
 971                 the output string; if negative, count from the right.
 972   value2      the length of the output string, or negative (-1) for unset
 973                 if value1 is positive, unset means "all after"
 974                 if value1 is negative, unset means "all before"
 975   len         set to the length of the returned string
 976
 977 Returns:      pointer to the output string, or NULL if there is an error
 978 */
 979
 980 static uschar *
 981 extract_substr(uschar *subject, int value1, int value2, int *len)
 982 {
 983 int sublen = Ustrlen(subject);
 984
 985 if (value1 < 0)    /* count from right */
 986   {
 987   value1 += sublen;
 988
 989   /* If the position is before the start, skip to the start, and adjust the
 990   length. If the length ends up negative, the substring is null because nothing
 991   can precede. This falls out naturally when the length is unset, meaning "all
 992   to the left". */
 993
 994   if (value1 < 0)
 995     {
 996     value2 += value1;
 997     if (value2 < 0) value2 = 0;
 998     value1 = 0;
 999     }
1000
1001   /* Otherwise an unset length => characters before value1 */
1002
1003   else if (value2 < 0)
1004     {
1005     value2 = value1;
1006     value1 = 0;
1007     }
1008   }
1009
1010 /* For a non-negative offset, if the starting position is past the end of the
1011 string, the result will be the null string. Otherwise, an unset length means
1012 "rest"; just set it to the maximum - it will be cut down below if necessary. */
1013
1014 else
1015   {
1016   if (value1 > sublen)
1017     {
1018     value1 = sublen;
1019     value2 = 0;
1020     }
1021   else if (value2 < 0) value2 = sublen;
1022   }
1023
1024 /* Cut the length down to the maximum possible for the offset value, and get
1025 the required characters. */
1026
1027 if (value1 + value2 > sublen) value2 = sublen - value1;
1028 *len = value2;
1029 return subject + value1;
1030 }
1031
1032
1033
1034
1035 /*************************************************
1036 *            Old-style hash of a string          *
1037 *************************************************/
1038
1039 /* Perform the ${hash expansion operation.
1040
1041 Arguments:
1042   subject     the input string (an expanded substring)
1043   value1      the length of the output string; if greater or equal to the
1044                 length of the input string, the input string is returned
1045   value2      the number of hash characters to use, or 26 if negative
1046   len         set to the length of the returned string
1047
1048 Returns:      pointer to the output string, or NULL if there is an error
1049 */
1050
1051 static uschar *
1052 compute_hash(uschar *subject, int value1, int value2, int *len)
1053 {
1054 int sublen = Ustrlen(subject);
1055
1056 if (value2 < 0) value2 = 26;
1057 else if (value2 > Ustrlen(hashcodes))
1058   {
1059   expand_string_message =
1060     string_sprintf("hash count \"%d\" too big", value2);
1061   return NULL;
1062   }
1063
1064 /* Calculate the hash text. We know it is shorter than the original string, so
1065 can safely place it in subject[] (we know that subject is always itself an
1066 expanded substring). */
1067
1068 if (value1 < sublen)
1069   {
1070   int c;
1071   int i = 0;
1072   int j = value1;
1073   while ((c = (subject[j])) != 0)
1074     {
1075     int shift = (c + j++) & 7;
1076     subject[i] ^= (c << shift) | (c >> (8-shift));
1077     if (++i >= value1) i = 0;
1078     }
1079   for (i = 0; i < value1; i++)
1080     subject[i] = hashcodes[(subject[i]) % value2];
1081   }
1082 else value1 = sublen;
1083
1084 *len = value1;
1085 return subject;
1086 }
1087
1088
1089
1090
1091 /*************************************************
1092 *             Numeric hash of a string           *
1093 *************************************************/
1094
1095 /* Perform the ${nhash expansion operation. The first characters of the
1096 string are treated as most important, and get the highest prime numbers.
1097
1098 Arguments:
1099   subject     the input string
1100   value1      the maximum value of the first part of the result
1101   value2      the maximum value of the second part of the result,
1102                 or negative to produce only a one-part result
1103   len         set to the length of the returned string
1104
1105 Returns:  pointer to the output string, or NULL if there is an error.
1106 */
1107
1108 static uschar *
1109 compute_nhash (uschar *subject, int value1, int value2, int *len)
1110 {
1111 uschar *s = subject;
1112 int i = 0;
1113 unsigned long int total = 0; /* no overflow */
1114
1115 while (*s != 0)
1116   {
1117   if (i == 0) i = sizeof(prime)/sizeof(int) - 1;
1118   total += prime[i--] * (unsigned int)(*s++);
1119   }
1120
1121 /* If value2 is unset, just compute one number */
1122
1123 if (value2 < 0)
1124   {
1125   s = string_sprintf("%d", total % value1);
1126   }
1127
1128 /* Otherwise do a div/mod hash */
1129
1130 else
1131   {
1132   total = total % (value1 * value2);
1133   s = string_sprintf("%d/%d", total/value2, total % value2);
1134   }
1135
1136 *len = Ustrlen(s);
1137 return s;
1138 }
1139
1140
1141
1142
1143
1144 /*************************************************
1145 *     Find the value of a header or headers      *
1146 *************************************************/
1147
1148 /* Multiple instances of the same header get concatenated, and this function
1149 can also return a concatenation of all the header lines. When concatenating
1150 specific headers that contain lists of addresses, a comma is inserted between
1151 them. Otherwise we use a straight concatenation. Because some messages can have
1152 pathologically large number of lines, there is a limit on the length that is
1153 returned. Also, to avoid massive store use which would result from using
1154 string_cat() as it copies and extends strings, we do a preliminary pass to find
1155 out exactly how much store will be needed. On "normal" messages this will be
1156 pretty trivial.
1157
1158 Arguments:
1159   name          the name of the header, without the leading $header_ or $h_,
1160                 or NULL if a concatenation of all headers is required
1161   exists_only   TRUE if called from a def: test; don't need to build a string;
1162                 just return a string that is not "" and not "0" if the header
1163                 exists
1164   newsize       return the size of memory block that was obtained; may be NULL
1165                 if exists_only is TRUE
1166   want_raw      TRUE if called for $rh_ or $rheader_ variables; no processing,
1167                 other than concatenating, will be done on the header. Also used
1168                 for $message_headers_raw.
1169   charset       name of charset to translate MIME words to; used only if
1170                 want_raw is false; if NULL, no translation is done (this is
1171                 used for $bh_ and $bheader_)
1172
1173 Returns:        NULL if the header does not exist, else a pointer to a new
1174                 store block
1175 */
1176
1177 static uschar *
1178 find_header(uschar *name, BOOL exists_only, int *newsize, BOOL want_raw,
1179   uschar *charset)
1180 {
1181 BOOL found = name == NULL;
1182 int comma = 0;
1183 int len = found? 0 : Ustrlen(name);
1184 int i;
1185 uschar *yield = NULL;
1186 uschar *ptr = NULL;
1187
1188 /* Loop for two passes - saves code repetition */
1189
1190 for (i = 0; i < 2; i++)
1191   {
1192   int size = 0;
1193   header_line *h;
1194
1195   for (h = header_list; size < header_insert_maxlen && h != NULL; h = h->next)
1196     {
1197     if (h->type != htype_old && h->text != NULL)  /* NULL => Received: placeholder */
1198       {
1199       if (name == NULL || (len <= h->slen && strncmpic(name, h->text, len) == 0))
1200         {
1201         int ilen;
1202         uschar *t;
1203
1204         if (exists_only) return US"1";      /* don't need actual string */
1205         found = TRUE;
1206         t = h->text + len;                  /* text to insert */
1207         if (!want_raw)                      /* unless wanted raw, */
1208           while (isspace(*t)) t++;          /* remove leading white space */
1209         ilen = h->slen - (t - h->text);     /* length to insert */
1210
1211         /* Unless wanted raw, remove trailing whitespace, including the
1212         newline. */
1213
1214         if (!want_raw)
1215           while (ilen > 0 && isspace(t[ilen-1])) ilen--;
1216
1217         /* Set comma = 1 if handling a single header and it's one of those
1218         that contains an address list, except when asked for raw headers. Only
1219         need to do this once. */
1220
1221         if (!want_raw && name != NULL && comma == 0 &&
1222             Ustrchr("BCFRST", h->type) != NULL)
1223           comma = 1;
1224
1225         /* First pass - compute total store needed; second pass - compute
1226         total store used, including this header. */
1227
1228         size += ilen + comma + 1;  /* +1 for the newline */
1229
1230         /* Second pass - concatentate the data, up to a maximum. Note that
1231         the loop stops when size hits the limit. */
1232
1233         if (i != 0)
1234           {
1235           if (size > header_insert_maxlen)
1236             {
1237             ilen -= size - header_insert_maxlen - 1;
1238             comma = 0;
1239             }
1240           Ustrncpy(ptr, t, ilen);
1241           ptr += ilen;
1242
1243           /* For a non-raw header, put in the comma if needed, then add
1244           back the newline we removed above, provided there was some text in
1245           the header. */
1246
1247           if (!want_raw && ilen > 0)
1248             {
1249             if (comma != 0) *ptr++ = ',';
1250             *ptr++ = '\n';
1251             }
1252           }
1253         }
1254       }
1255     }
1256
1257   /* At end of first pass, return NULL if no header found. Then truncate size
1258   if necessary, and get the buffer to hold the data, returning the buffer size.
1259   */
1260
1261   if (i == 0)
1262     {
1263     if (!found) return NULL;
1264     if (size > header_insert_maxlen) size = header_insert_maxlen;
1265     *newsize = size + 1;
1266     ptr = yield = store_get(*newsize);
1267     }
1268   }
1269
1270 /* That's all we do for raw header expansion. */
1271
1272 if (want_raw)
1273   {
1274   *ptr = 0;
1275   }
1276
1277 /* Otherwise, remove a final newline and a redundant added comma. Then we do
1278 RFC 2047 decoding, translating the charset if requested. The rfc2047_decode2()
1279 function can return an error with decoded data if the charset translation
1280 fails. If decoding fails, it returns NULL. */
1281
1282 else
1283   {
1284   uschar *decoded, *error;
1285   if (ptr > yield && ptr[-1] == '\n') ptr--;
1286   if (ptr > yield && comma != 0 && ptr[-1] == ',') ptr--;
1287   *ptr = 0;
1288   decoded = rfc2047_decode2(yield, check_rfc2047_length, charset, '?', NULL,
1289     newsize, &error);
1290   if (error != NULL)
1291     {
1292     DEBUG(D_any) debug_printf("*** error in RFC 2047 decoding: %s\n"
1293       "    input was: %s\n", error, yield);
1294     }
1295   if (decoded != NULL) yield = decoded;
1296   }
1297
1298 return yield;
1299 }
1300
1301
1302
1303
1304 /*************************************************
1305 *               Find value of a variable         *
1306 *************************************************/
1307
1308 /* The table of variables is kept in alphabetic order, so we can search it
1309 using a binary chop. The "choplen" variable is nothing to do with the binary
1310 chop.
1311
1312 Arguments:
1313   name          the name of the variable being sought
1314   exists_only   TRUE if this is a def: test; passed on to find_header()
1315   skipping      TRUE => skip any processing evaluation; this is not the same as
1316                   exists_only because def: may test for values that are first
1317                   evaluated here
1318   newsize       pointer to an int which is initially zero; if the answer is in
1319                 a new memory buffer, *newsize is set to its size
1320
1321 Returns:        NULL if the variable does not exist, or
1322                 a pointer to the variable's contents, or
1323                 something non-NULL if exists_only is TRUE
1324 */
1325
1326 static uschar *
1327 find_variable(uschar *name, BOOL exists_only, BOOL skipping, int *newsize)
1328 {
1329 int first = 0;
1330 int last = var_table_size;
1331
1332 /* Handle ACL variables, whose names are of the form acl_cxxx or acl_mxxx.
1333 Originally, xxx had to be a number in the range 0-9 (later 0-19), but from
1334 release 4.64 onwards arbitrary names are permitted, as long as the first 5
1335 characters are acl_c or acl_m and the sixth is either a digit or an underscore
1336 (this gave backwards compatibility at the changeover). There may be built-in
1337 variables whose names start acl_ but they should never start in this way. This
1338 slightly messy specification is a consequence of the history, needless to say.
1339
1340 If an ACL variable does not exist, treat it as empty, unless strict_acl_vars is
1341 set, in which case give an error. */
1342
1343 if ((Ustrncmp(name, "acl_c", 5) == 0 || Ustrncmp(name, "acl_m", 5) == 0) &&
1344      !isalpha(name[5]))
1345   {
1346   tree_node *node =
1347     tree_search((name[4] == 'c')? acl_var_c : acl_var_m, name + 4);
1348   return (node == NULL)? (strict_acl_vars? NULL : US"") : node->data.ptr;
1349   }
1350
1351 /* Handle $auth<n> variables. */
1352
1353 if (Ustrncmp(name, "auth", 4) == 0)
1354   {
1355   uschar *endptr;
1356   int n = Ustrtoul(name + 4, &endptr, 10);
1357   if (*endptr == 0 && n != 0 && n <= AUTH_VARS)
1358     return (auth_vars[n-1] == NULL)? US"" : auth_vars[n-1];
1359   }
1360
1361 /* For all other variables, search the table */
1362
1363 while (last > first)
1364   {
1365   uschar *s, *domain;
1366   uschar **ss;
1367   int middle = (first + last)/2;
1368   int c = Ustrcmp(name, var_table[middle].name);
1369
1370   if (c > 0) { first = middle + 1; continue; }
1371   if (c < 0) { last = middle; continue; }
1372
1373   /* Found an existing variable. If in skipping state, the value isn't needed,
1374   and we want to avoid processing (such as looking up the host name). */
1375
1376   if (skipping) return US"";
1377
1378   switch (var_table[middle].type)
1379     {
1380 #ifdef EXPERIMENTAL_DOMAINKEYS
1381
1382     case vtype_dk_verify:
1383     if (dk_verify_block == NULL) return US"";
1384     s = NULL;
1385     if (Ustrcmp(var_table[middle].name, "dk_result") == 0)
1386       s = dk_verify_block->result_string;
1387     if (Ustrcmp(var_table[middle].name, "dk_sender") == 0)
1388       s = dk_verify_block->address;
1389     if (Ustrcmp(var_table[middle].name, "dk_sender_domain") == 0)
1390       s = dk_verify_block->domain;
1391     if (Ustrcmp(var_table[middle].name, "dk_sender_local_part") == 0)
1392       s = dk_verify_block->local_part;
1393
1394     if (Ustrcmp(var_table[middle].name, "dk_sender_source") == 0)
1395       switch(dk_verify_block->address_source) {
1396         case DK_EXIM_ADDRESS_NONE: s = US"0"; break;
1397         case DK_EXIM_ADDRESS_FROM_FROM: s = US"from"; break;
1398         case DK_EXIM_ADDRESS_FROM_SENDER: s = US"sender"; break;
1399       }
1400
1401     if (Ustrcmp(var_table[middle].name, "dk_status") == 0)
1402       switch(dk_verify_block->result) {
1403         case DK_EXIM_RESULT_ERR: s = US"error"; break;
1404         case DK_EXIM_RESULT_BAD_FORMAT: s = US"bad format"; break;
1405         case DK_EXIM_RESULT_NO_KEY: s = US"no key"; break;
1406         case DK_EXIM_RESULT_NO_SIGNATURE: s = US"no signature"; break;
1407         case DK_EXIM_RESULT_REVOKED: s = US"revoked"; break;
1408         case DK_EXIM_RESULT_NON_PARTICIPANT: s = US"non-participant"; break;
1409         case DK_EXIM_RESULT_GOOD: s = US"good"; break;
1410         case DK_EXIM_RESULT_BAD: s = US"bad"; break;
1411       }
1412
1413     if (Ustrcmp(var_table[middle].name, "dk_signsall") == 0)
1414       s = (dk_verify_block->signsall)? US"1" : US"0";
1415
1416     if (Ustrcmp(var_table[middle].name, "dk_testing") == 0)
1417       s = (dk_verify_block->testing)? US"1" : US"0";
1418
1419     if (Ustrcmp(var_table[middle].name, "dk_is_signed") == 0)
1420       s = (dk_verify_block->is_signed)? US"1" : US"0";
1421
1422     return (s == NULL)? US"" : s;
1423 #endif
1424
1425     case vtype_filter_int:
1426     if (!filter_running) return NULL;
1427     /* Fall through */
1428     /* VVVVVVVVVVVV */
1429     case vtype_int:
1430     sprintf(CS var_buffer, "%d", *(int *)(var_table[middle].value)); /* Integer */
1431     return var_buffer;
1432
1433     case vtype_ino:
1434     sprintf(CS var_buffer, "%ld", (long int)(*(ino_t *)(var_table[middle].value))); /* Inode */
1435     return var_buffer;
1436
1437     case vtype_gid:
1438     sprintf(CS var_buffer, "%ld", (long int)(*(gid_t *)(var_table[middle].value))); /* gid */
1439     return var_buffer;
1440
1441     case vtype_uid:
1442     sprintf(CS var_buffer, "%ld", (long int)(*(uid_t *)(var_table[middle].value))); /* uid */
1443     return var_buffer;
1444
1445     case vtype_stringptr:                      /* Pointer to string */
1446     s = *((uschar **)(var_table[middle].value));
1447     return (s == NULL)? US"" : s;
1448
1449     case vtype_pid:
1450     sprintf(CS var_buffer, "%d", (int)getpid()); /* pid */
1451     return var_buffer;
1452
1453     case vtype_load_avg:
1454     sprintf(CS var_buffer, "%d", OS_GETLOADAVG()); /* load_average */
1455     return var_buffer;
1456
1457     case vtype_host_lookup:                    /* Lookup if not done so */
1458     if (sender_host_name == NULL && sender_host_address != NULL &&
1459         !host_lookup_failed && host_name_lookup() == OK)
1460       host_build_sender_fullhost();
1461     return (sender_host_name == NULL)? US"" : sender_host_name;
1462
1463     case vtype_localpart:                      /* Get local part from address */
1464     s = *((uschar **)(var_table[middle].value));
1465     if (s == NULL) return US"";
1466     domain = Ustrrchr(s, '@');
1467     if (domain == NULL) return s;
1468     if (domain - s > sizeof(var_buffer) - 1)
1469       log_write(0, LOG_MAIN|LOG_PANIC_DIE, "local part longer than %d in "
1470         "string expansion", sizeof(var_buffer));
1471     Ustrncpy(var_buffer, s, domain - s);
1472     var_buffer[domain - s] = 0;
1473     return var_buffer;
1474
1475     case vtype_domain:                         /* Get domain from address */
1476     s = *((uschar **)(var_table[middle].value));
1477     if (s == NULL) return US"";
1478     domain = Ustrrchr(s, '@');
1479     return (domain == NULL)? US"" : domain + 1;
1480
1481     case vtype_msgheaders:
1482     return find_header(NULL, exists_only, newsize, FALSE, NULL);
1483
1484     case vtype_msgheaders_raw:
1485     return find_header(NULL, exists_only, newsize, TRUE, NULL);
1486
1487     case vtype_msgbody:                        /* Pointer to msgbody string */
1488     case vtype_msgbody_end:                    /* Ditto, the end of the msg */
1489     ss = (uschar **)(var_table[middle].value);
1490     if (*ss == NULL && deliver_datafile >= 0)  /* Read body when needed */
1491       {
1492       uschar *body;
1493       off_t start_offset = SPOOL_DATA_START_OFFSET;
1494       int len = message_body_visible;
1495       if (len > message_size) len = message_size;
1496       *ss = body = store_malloc(len+1);
1497       body[0] = 0;
1498       if (var_table[middle].type == vtype_msgbody_end)
1499         {
1500         struct stat statbuf;
1501         if (fstat(deliver_datafile, &statbuf) == 0)
1502           {
1503           start_offset = statbuf.st_size - len;
1504           if (start_offset < SPOOL_DATA_START_OFFSET)
1505             start_offset = SPOOL_DATA_START_OFFSET;
1506           }
1507         }
1508       lseek(deliver_datafile, start_offset, SEEK_SET);
1509       len = read(deliver_datafile, body, len);
1510       if (len > 0)
1511         {
1512         body[len] = 0;
1513         if (message_body_newlines)   /* Separate loops for efficiency */
1514           {
1515           while (len > 0)
1516             { if (body[--len] == 0) body[len] = ' '; }
1517           }
1518         else
1519           {
1520           while (len > 0)
1521             { if (body[--len] == '\n' || body[len] == 0) body[len] = ' '; }
1522           }
1523         }
1524       }
1525     return (*ss == NULL)? US"" : *ss;
1526
1527     case vtype_todbsdin:                       /* BSD inbox time of day */
1528     return tod_stamp(tod_bsdin);
1529
1530     case vtype_tode:                           /* Unix epoch time of day */
1531     return tod_stamp(tod_epoch);
1532
1533     case vtype_todf:                           /* Full time of day */
1534     return tod_stamp(tod_full);
1535
1536     case vtype_todl:                           /* Log format time of day */
1537     return tod_stamp(tod_log_bare);            /* (without timezone) */
1538
1539     case vtype_todzone:                        /* Time zone offset only */
1540     return tod_stamp(tod_zone);
1541
1542     case vtype_todzulu:                        /* Zulu time */
1543     return tod_stamp(tod_zulu);
1544
1545     case vtype_todlf:                          /* Log file datestamp tod */
1546     return tod_stamp(tod_log_datestamp);
1547
1548     case vtype_reply:                          /* Get reply address */
1549     s = find_header(US"reply-to:", exists_only, newsize, TRUE,
1550       headers_charset);
1551     if (s != NULL) while (isspace(*s)) s++;
1552     if (s == NULL || *s == 0)
1553       {
1554       *newsize = 0;                            /* For the *s==0 case */
1555       s = find_header(US"from:", exists_only, newsize, TRUE, headers_charset);
1556       }
1557     if (s != NULL)
1558       {
1559       uschar *t;
1560       while (isspace(*s)) s++;
1561       for (t = s; *t != 0; t++) if (*t == '\n') *t = ' ';
1562       while (t > s && isspace(t[-1])) t--;
1563       *t = 0;
1564       }
1565     return (s == NULL)? US"" : s;
1566
1567     /* A recipients list is available only during system message filtering,
1568     during ACL processing after DATA, and while expanding pipe commands
1569     generated from a system filter, but not elsewhere. */
1570
1571     case vtype_recipients:
1572     if (!enable_dollar_recipients) return NULL; else
1573       {
1574       int size = 128;
1575       int ptr = 0;
1576       int i;
1577       s = store_get(size);
1578       for (i = 0; i < recipients_count; i++)
1579         {
1580         if (i != 0) s = string_cat(s, &size, &ptr, US", ", 2);
1581         s = string_cat(s, &size, &ptr, recipients_list[i].address,
1582           Ustrlen(recipients_list[i].address));
1583         }
1584       s[ptr] = 0;     /* string_cat() leaves room */
1585       }
1586     return s;
1587
1588     case vtype_pspace:
1589       {
1590       int inodes;
1591       sprintf(CS var_buffer, "%d",
1592         receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes));
1593       }
1594     return var_buffer;
1595
1596     case vtype_pinodes:
1597       {
1598       int inodes;
1599       (void) receive_statvfs(var_table[middle].value == (void *)TRUE, &inodes);
1600       sprintf(CS var_buffer, "%d", inodes);
1601       }
1602     return var_buffer;
1603     }
1604   }
1605
1606 return NULL;          /* Unknown variable name */
1607 }
1608
1609
1610
1611
1612 /*************************************************
1613 *           Read and expand substrings           *
1614 *************************************************/
1615
1616 /* This function is called to read and expand argument substrings for various
1617 expansion items. Some have a minimum requirement that is less than the maximum;
1618 in these cases, the first non-present one is set to NULL.
1619
1620 Arguments:
1621   sub        points to vector of pointers to set
1622   n          maximum number of substrings
1623   m          minimum required
1624   sptr       points to current string pointer
1625   skipping   the skipping flag
1626   check_end  if TRUE, check for final '}'
1627   name       name of item, for error message
1628
1629 Returns:     0 OK; string pointer updated
1630              1 curly bracketing error (too few arguments)
1631              2 too many arguments (only if check_end is set); message set
1632              3 other error (expansion failure)
1633 */
1634
1635 static int
1636 read_subs(uschar **sub, int n, int m, uschar **sptr, BOOL skipping,
1637   BOOL check_end, uschar *name)
1638 {
1639 int i;
1640 uschar *s = *sptr;
1641
1642 while (isspace(*s)) s++;
1643 for (i = 0; i < n; i++)
1644   {
1645   if (*s != '{')
1646     {
1647     if (i < m) return 1;
1648     sub[i] = NULL;
1649     break;
1650     }
1651   sub[i] = expand_string_internal(s+1, TRUE, &s, skipping);
1652   if (sub[i] == NULL) return 3;
1653   if (*s++ != '}') return 1;
1654   while (isspace(*s)) s++;
1655   }
1656 if (check_end && *s++ != '}')
1657   {
1658   if (s[-1] == '{')
1659     {
1660     expand_string_message = string_sprintf("Too many arguments for \"%s\" "
1661       "(max is %d)", name, n);
1662     return 2;
1663     }
1664   return 1;
1665   }
1666
1667 *sptr = s;
1668 return 0;
1669 }
1670
1671
1672
1673
1674 /*************************************************
1675 *     Elaborate message for bad variable         *
1676 *************************************************/
1677
1678 /* For the "unknown variable" message, take a look at the variable's name, and
1679 give additional information about possible ACL variables. The extra information
1680 is added on to expand_string_message.
1681
1682 Argument:   the name of the variable
1683 Returns:    nothing
1684 */
1685
1686 static void
1687 check_variable_error_message(uschar *name)
1688 {
1689 if (Ustrncmp(name, "acl_", 4) == 0)
1690   expand_string_message = string_sprintf("%s (%s)", expand_string_message,
1691     (name[4] == 'c' || name[4] == 'm')?
1692       (isalpha(name[5])?
1693         US"6th character of a user-defined ACL variable must be a digit or underscore" :
1694         US"strict_acl_vars is set"    /* Syntax is OK, it has to be this */
1695       ) :
1696       US"user-defined ACL variables must start acl_c or acl_m");
1697 }
1698
1699
1700
1701 /*************************************************
1702 *        Read and evaluate a condition           *
1703 *************************************************/
1704
1705 /*
1706 Arguments:
1707   s        points to the start of the condition text
1708   yield    points to a BOOL to hold the result of the condition test;
1709            if NULL, we are just reading through a condition that is
1710            part of an "or" combination to check syntax, or in a state
1711            where the answer isn't required
1712
1713 Returns:   a pointer to the first character after the condition, or
1714            NULL after an error
1715 */
1716
1717 static uschar *
1718 eval_condition(uschar *s, BOOL *yield)
1719 {
1720 BOOL testfor = TRUE;
1721 BOOL tempcond, combined_cond;
1722 BOOL *subcondptr;
1723 int i, rc, cond_type, roffset;
1724 int num[2];
1725 struct stat statbuf;
1726 uschar name[256];
1727 uschar *sub[4];
1728
1729 const pcre *re;
1730 const uschar *rerror;
1731
1732 for (;;)
1733   {
1734   while (isspace(*s)) s++;
1735   if (*s == '!') { testfor = !testfor; s++; } else break;
1736   }
1737
1738 /* Numeric comparisons are symbolic */
1739
1740 if (*s == '=' || *s == '>' || *s == '<')
1741   {
1742   int p = 0;
1743   name[p++] = *s++;
1744   if (*s == '=')
1745     {
1746     name[p++] = '=';
1747     s++;
1748     }
1749   name[p] = 0;
1750   }
1751
1752 /* All other conditions are named */
1753
1754 else s = read_name(name, 256, s, US"_");
1755
1756 /* If we haven't read a name, it means some non-alpha character is first. */
1757
1758 if (name[0] == 0)
1759   {
1760   expand_string_message = string_sprintf("condition name expected, "
1761     "but found \"%.16s\"", s);
1762   return NULL;
1763   }
1764
1765 /* Find which condition we are dealing with, and switch on it */
1766
1767 cond_type = chop_match(name, cond_table, sizeof(cond_table)/sizeof(uschar *));
1768 switch(cond_type)
1769   {
1770   /* def: tests for a non-empty variable, or for the existence of a header. If
1771   yield == NULL we are in a skipping state, and don't care about the answer. */
1772
1773   case ECOND_DEF:
1774   if (*s != ':')
1775     {
1776     expand_string_message = US"\":\" expected after \"def\"";
1777     return NULL;
1778     }
1779
1780   s = read_name(name, 256, s+1, US"_");
1781
1782   /* Test for a header's existence. If the name contains a closing brace
1783   character, this may be a user error where the terminating colon has been
1784   omitted. Set a flag to adjust a subsequent error message in this case. */
1785
1786   if (Ustrncmp(name, "h_", 2) == 0 ||
1787       Ustrncmp(name, "rh_", 3) == 0 ||
1788       Ustrncmp(name, "bh_", 3) == 0 ||
1789       Ustrncmp(name, "header_", 7) == 0 ||
1790       Ustrncmp(name, "rheader_", 8) == 0 ||
1791       Ustrncmp(name, "bheader_", 8) == 0)
1792     {
1793     s = read_header_name(name, 256, s);
1794     if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
1795     if (yield != NULL) *yield =
1796       (find_header(name, TRUE, NULL, FALSE, NULL) != NULL) == testfor;
1797     }
1798
1799   /* Test for a variable's having a non-empty value. A non-existent variable
1800   causes an expansion failure. */
1801
1802   else
1803     {
1804     uschar *value = find_variable(name, TRUE, yield == NULL, NULL);
1805     if (value == NULL)
1806       {
1807       expand_string_message = (name[0] == 0)?
1808         string_sprintf("variable name omitted after \"def:\"") :
1809         string_sprintf("unknown variable \"%s\" after \"def:\"", name);
1810       check_variable_error_message(name);
1811       return NULL;
1812       }
1813     if (yield != NULL) *yield = (value[0] != 0) == testfor;
1814     }
1815
1816   return s;
1817
1818
1819   /* first_delivery tests for first delivery attempt */
1820
1821   case ECOND_FIRST_DELIVERY:
1822   if (yield != NULL) *yield = deliver_firsttime == testfor;
1823   return s;
1824
1825
1826   /* queue_running tests for any process started by a queue runner */
1827
1828   case ECOND_QUEUE_RUNNING:
1829   if (yield != NULL) *yield = (queue_run_pid != (pid_t)0) == testfor;
1830   return s;
1831
1832
1833   /* exists:  tests for file existence
1834        isip:  tests for any IP address
1835       isip4:  tests for an IPv4 address
1836       isip6:  tests for an IPv6 address
1837         pam:  does PAM authentication
1838      radius:  does RADIUS authentication
1839    ldapauth:  does LDAP authentication
1840     pwcheck:  does Cyrus SASL pwcheck authentication
1841   */
1842
1843   case ECOND_EXISTS:
1844   case ECOND_ISIP:
1845   case ECOND_ISIP4:
1846   case ECOND_ISIP6:
1847   case ECOND_PAM:
1848   case ECOND_RADIUS:
1849   case ECOND_LDAPAUTH:
1850   case ECOND_PWCHECK:
1851
1852   while (isspace(*s)) s++;
1853   if (*s != '{') goto COND_FAILED_CURLY_START;
1854
1855   sub[0] = expand_string_internal(s+1, TRUE, &s, yield == NULL);
1856   if (sub[0] == NULL) return NULL;
1857   if (*s++ != '}') goto COND_FAILED_CURLY_END;
1858
1859   if (yield == NULL) return s;   /* No need to run the test if skipping */
1860
1861   switch(cond_type)
1862     {
1863     case ECOND_EXISTS:
1864     if ((expand_forbid & RDO_EXISTS) != 0)
1865       {
1866       expand_string_message = US"File existence tests are not permitted";
1867       return NULL;
1868       }
1869     *yield = (Ustat(sub[0], &statbuf) == 0) == testfor;
1870     break;
1871
1872     case ECOND_ISIP:
1873     case ECOND_ISIP4:
1874     case ECOND_ISIP6:
1875     rc = string_is_ip_address(sub[0], NULL);
1876     *yield = ((cond_type == ECOND_ISIP)? (rc != 0) :
1877              (cond_type == ECOND_ISIP4)? (rc == 4) : (rc == 6)) == testfor;
1878     break;
1879
1880     /* Various authentication tests - all optionally compiled */
1881
1882     case ECOND_PAM:
1883     #ifdef SUPPORT_PAM
1884     rc = auth_call_pam(sub[0], &expand_string_message);
1885     goto END_AUTH;
1886     #else
1887     goto COND_FAILED_NOT_COMPILED;
1888     #endif  /* SUPPORT_PAM */
1889
1890     case ECOND_RADIUS:
1891     #ifdef RADIUS_CONFIG_FILE
1892     rc = auth_call_radius(sub[0], &expand_string_message);
1893     goto END_AUTH;
1894     #else
1895     goto COND_FAILED_NOT_COMPILED;
1896     #endif  /* RADIUS_CONFIG_FILE */
1897
1898     case ECOND_LDAPAUTH:
1899     #ifdef LOOKUP_LDAP
1900       {
1901       /* Just to keep the interface the same */
1902       BOOL do_cache;
1903       int old_pool = store_pool;
1904       store_pool = POOL_SEARCH;
1905       rc = eldapauth_find((void *)(-1), NULL, sub[0], Ustrlen(sub[0]), NULL,
1906         &expand_string_message, &do_cache);
1907       store_pool = old_pool;
1908       }
1909     goto END_AUTH;
1910     #else
1911     goto COND_FAILED_NOT_COMPILED;
1912     #endif  /* LOOKUP_LDAP */
1913
1914     case ECOND_PWCHECK:
1915     #ifdef CYRUS_PWCHECK_SOCKET
1916     rc = auth_call_pwcheck(sub[0], &expand_string_message);
1917     goto END_AUTH;
1918     #else
1919     goto COND_FAILED_NOT_COMPILED;
1920     #endif  /* CYRUS_PWCHECK_SOCKET */
1921
1922     #if defined(SUPPORT_PAM) || defined(RADIUS_CONFIG_FILE) || \
1923         defined(LOOKUP_LDAP) || defined(CYRUS_PWCHECK_SOCKET)
1924     END_AUTH:
1925     if (rc == ERROR || rc == DEFER) return NULL;
1926     *yield = (rc == OK) == testfor;
1927     #endif
1928     }
1929   return s;
1930
1931
1932   /* saslauthd: does Cyrus saslauthd authentication. Four parameters are used:
1933
1934      ${if saslauthd {{username}{password}{service}{realm}}  {yes}[no}}
1935
1936   However, the last two are optional. That is why the whole set is enclosed
1937   in their own set or braces. */
1938
1939   case ECOND_SASLAUTHD:
1940   #ifndef CYRUS_SASLAUTHD_SOCKET
1941   goto COND_FAILED_NOT_COMPILED;
1942   #else
1943   while (isspace(*s)) s++;
1944   if (*s++ != '{') goto COND_FAILED_CURLY_START;
1945   switch(read_subs(sub, 4, 2, &s, yield == NULL, TRUE, US"saslauthd"))
1946     {
1947     case 1: expand_string_message = US"too few arguments or bracketing "
1948       "error for saslauthd";
1949     case 2:
1950     case 3: return NULL;
1951     }
1952   if (sub[2] == NULL) sub[3] = NULL;  /* realm if no service */
1953   if (yield != NULL)
1954     {
1955     int rc;
1956     rc = auth_call_saslauthd(sub[0], sub[1], sub[2], sub[3],
1957       &expand_string_message);
1958     if (rc == ERROR || rc == DEFER) return NULL;
1959     *yield = (rc == OK) == testfor;
1960     }
1961   return s;
1962   #endif /* CYRUS_SASLAUTHD_SOCKET */
1963
1964
1965   /* symbolic operators for numeric and string comparison, and a number of
1966   other operators, all requiring two arguments.
1967
1968   match:             does a regular expression match and sets up the numerical
1969                        variables if it succeeds
1970   match_address:     matches in an address list
1971   match_domain:      matches in a domain list
1972   match_ip:          matches a host list that is restricted to IP addresses
1973   match_local_part:  matches in a local part list
1974   crypteq:           encrypts plaintext and compares against an encrypted text,
1975                        using crypt(), crypt16(), MD5 or SHA-1
1976   */
1977
1978   case ECOND_MATCH:
1979   case ECOND_MATCH_ADDRESS:
1980   case ECOND_MATCH_DOMAIN:
1981   case ECOND_MATCH_IP:
1982   case ECOND_MATCH_LOCAL_PART:
1983   case ECOND_CRYPTEQ:
1984
1985   case ECOND_NUM_L:     /* Numerical comparisons */
1986   case ECOND_NUM_LE:
1987   case ECOND_NUM_E:
1988   case ECOND_NUM_EE:
1989   case ECOND_NUM_G:
1990   case ECOND_NUM_GE:
1991
1992   case ECOND_STR_LT:    /* String comparisons */
1993   case ECOND_STR_LTI:
1994   case ECOND_STR_LE:
1995   case ECOND_STR_LEI:
1996   case ECOND_STR_EQ:
1997   case ECOND_STR_EQI:
1998   case ECOND_STR_GT:
1999   case ECOND_STR_GTI:
2000   case ECOND_STR_GE:
2001   case ECOND_STR_GEI:
2002
2003   for (i = 0; i < 2; i++)
2004     {
2005     while (isspace(*s)) s++;
2006     if (*s != '{')
2007       {
2008       if (i == 0) goto COND_FAILED_CURLY_START;
2009       expand_string_message = string_sprintf("missing 2nd string in {} "
2010         "after \"%s\"", name);
2011       return NULL;
2012       }
2013     sub[i] = expand_string_internal(s+1, TRUE, &s, yield == NULL);
2014     if (sub[i] == NULL) return NULL;
2015     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2016
2017     /* Convert to numerical if required; we know that the names of all the
2018     conditions that compare numbers do not start with a letter. This just saves
2019     checking for them individually. */
2020
2021     if (!isalpha(name[0]) && yield != NULL)
2022       {
2023       if (sub[i][0] == 0)
2024         {
2025         num[i] = 0;
2026         DEBUG(D_expand)
2027           debug_printf("empty string cast to zero for numerical comparison\n");
2028         }
2029       else
2030         {
2031         num[i] = expand_string_integer(sub[i], FALSE);
2032         if (expand_string_message != NULL) return NULL;
2033         }
2034       }
2035     }
2036
2037   /* Result not required */
2038
2039   if (yield == NULL) return s;
2040
2041   /* Do an appropriate comparison */
2042
2043   switch(cond_type)
2044     {
2045     case ECOND_NUM_E:
2046     case ECOND_NUM_EE:
2047     *yield = (num[0] == num[1]) == testfor;
2048     break;
2049
2050     case ECOND_NUM_G:
2051     *yield = (num[0] > num[1]) == testfor;
2052     break;
2053
2054     case ECOND_NUM_GE:
2055     *yield = (num[0] >= num[1]) == testfor;
2056     break;
2057
2058     case ECOND_NUM_L:
2059     *yield = (num[0] < num[1]) == testfor;
2060     break;
2061
2062     case ECOND_NUM_LE:
2063     *yield = (num[0] <= num[1]) == testfor;
2064     break;
2065
2066     case ECOND_STR_LT:
2067     *yield = (Ustrcmp(sub[0], sub[1]) < 0) == testfor;
2068     break;
2069
2070     case ECOND_STR_LTI:
2071     *yield = (strcmpic(sub[0], sub[1]) < 0) == testfor;
2072     break;
2073
2074     case ECOND_STR_LE:
2075     *yield = (Ustrcmp(sub[0], sub[1]) <= 0) == testfor;
2076     break;
2077
2078     case ECOND_STR_LEI:
2079     *yield = (strcmpic(sub[0], sub[1]) <= 0) == testfor;
2080     break;
2081
2082     case ECOND_STR_EQ:
2083     *yield = (Ustrcmp(sub[0], sub[1]) == 0) == testfor;
2084     break;
2085
2086     case ECOND_STR_EQI:
2087     *yield = (strcmpic(sub[0], sub[1]) == 0) == testfor;
2088     break;
2089
2090     case ECOND_STR_GT:
2091     *yield = (Ustrcmp(sub[0], sub[1]) > 0) == testfor;
2092     break;
2093
2094     case ECOND_STR_GTI:
2095     *yield = (strcmpic(sub[0], sub[1]) > 0) == testfor;
2096     break;
2097
2098     case ECOND_STR_GE:
2099     *yield = (Ustrcmp(sub[0], sub[1]) >= 0) == testfor;
2100     break;
2101
2102     case ECOND_STR_GEI:
2103     *yield = (strcmpic(sub[0], sub[1]) >= 0) == testfor;
2104     break;
2105
2106     case ECOND_MATCH:   /* Regular expression match */
2107     re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
2108       NULL);
2109     if (re == NULL)
2110       {
2111       expand_string_message = string_sprintf("regular expression error in "
2112         "\"%s\": %s at offset %d", sub[1], rerror, roffset);
2113       return NULL;
2114       }
2115     *yield = regex_match_and_setup(re, sub[0], 0, -1) == testfor;
2116     break;
2117
2118     case ECOND_MATCH_ADDRESS:  /* Match in an address list */
2119     rc = match_address_list(sub[0], TRUE, FALSE, &(sub[1]), NULL, -1, 0, NULL);
2120     goto MATCHED_SOMETHING;
2121
2122     case ECOND_MATCH_DOMAIN:   /* Match in a domain list */
2123     rc = match_isinlist(sub[0], &(sub[1]), 0, &domainlist_anchor, NULL,
2124       MCL_DOMAIN + MCL_NOEXPAND, TRUE, NULL);
2125     goto MATCHED_SOMETHING;
2126
2127     case ECOND_MATCH_IP:       /* Match IP address in a host list */
2128     if (sub[0][0] != 0 && string_is_ip_address(sub[0], NULL) == 0)
2129       {
2130       expand_string_message = string_sprintf("\"%s\" is not an IP address",
2131         sub[0]);
2132       return NULL;
2133       }
2134     else
2135       {
2136       unsigned int *nullcache = NULL;
2137       check_host_block cb;
2138
2139       cb.host_name = US"";
2140       cb.host_address = sub[0];
2141
2142       /* If the host address starts off ::ffff: it is an IPv6 address in
2143       IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2144       addresses. */
2145
2146       cb.host_ipv4 = (Ustrncmp(cb.host_address, "::ffff:", 7) == 0)?
2147         cb.host_address + 7 : cb.host_address;
2148
2149       rc = match_check_list(
2150              &sub[1],                   /* the list */
2151              0,                         /* separator character */
2152              &hostlist_anchor,          /* anchor pointer */
2153              &nullcache,                /* cache pointer */
2154              check_host,                /* function for testing */
2155              &cb,                       /* argument for function */
2156              MCL_HOST,                  /* type of check */
2157              sub[0],                    /* text for debugging */
2158              NULL);                     /* where to pass back data */
2159       }
2160     goto MATCHED_SOMETHING;
2161
2162     case ECOND_MATCH_LOCAL_PART:
2163     rc = match_isinlist(sub[0], &(sub[1]), 0, &localpartlist_anchor, NULL,
2164       MCL_LOCALPART + MCL_NOEXPAND, TRUE, NULL);
2165     /* Fall through */
2166     /* VVVVVVVVVVVV */
2167     MATCHED_SOMETHING:
2168     switch(rc)
2169       {
2170       case OK:
2171       *yield = testfor;
2172       break;
2173
2174       case FAIL:
2175       *yield = !testfor;
2176       break;
2177
2178       case DEFER:
2179       expand_string_message = string_sprintf("unable to complete match "
2180         "against \"%s\": %s", sub[1], search_error_message);
2181       return NULL;
2182       }
2183
2184     break;
2185
2186     /* Various "encrypted" comparisons. If the second string starts with
2187     "{" then an encryption type is given. Default to crypt() or crypt16()
2188     (build-time choice). */
2189
2190     case ECOND_CRYPTEQ:
2191     #ifndef SUPPORT_CRYPTEQ
2192     goto COND_FAILED_NOT_COMPILED;
2193     #else
2194     if (strncmpic(sub[1], US"{md5}", 5) == 0)
2195       {
2196       int sublen = Ustrlen(sub[1]+5);
2197       md5 base;
2198       uschar digest[16];
2199
2200       md5_start(&base);
2201       md5_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2202
2203       /* If the length that we are comparing against is 24, the MD5 digest
2204       is expressed as a base64 string. This is the way LDAP does it. However,
2205       some other software uses a straightforward hex representation. We assume
2206       this if the length is 32. Other lengths fail. */
2207
2208       if (sublen == 24)
2209         {
2210         uschar *coded = auth_b64encode((uschar *)digest, 16);
2211         DEBUG(D_auth) debug_printf("crypteq: using MD5+B64 hashing\n"
2212           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2213         *yield = (Ustrcmp(coded, sub[1]+5) == 0) == testfor;
2214         }
2215       else if (sublen == 32)
2216         {
2217         int i;
2218         uschar coded[36];
2219         for (i = 0; i < 16; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2220         coded[32] = 0;
2221         DEBUG(D_auth) debug_printf("crypteq: using MD5+hex hashing\n"
2222           "  subject=%s\n  crypted=%s\n", coded, sub[1]+5);
2223         *yield = (strcmpic(coded, sub[1]+5) == 0) == testfor;
2224         }
2225       else
2226         {
2227         DEBUG(D_auth) debug_printf("crypteq: length for MD5 not 24 or 32: "
2228           "fail\n  crypted=%s\n", sub[1]+5);
2229         *yield = !testfor;
2230         }
2231       }
2232
2233     else if (strncmpic(sub[1], US"{sha1}", 6) == 0)
2234       {
2235       int sublen = Ustrlen(sub[1]+6);
2236       sha1 base;
2237       uschar digest[20];
2238
2239       sha1_start(&base);
2240       sha1_end(&base, (uschar *)sub[0], Ustrlen(sub[0]), digest);
2241
2242       /* If the length that we are comparing against is 28, assume the SHA1
2243       digest is expressed as a base64 string. If the length is 40, assume a
2244       straightforward hex representation. Other lengths fail. */
2245
2246       if (sublen == 28)
2247         {
2248         uschar *coded = auth_b64encode((uschar *)digest, 20);
2249         DEBUG(D_auth) debug_printf("crypteq: using SHA1+B64 hashing\n"
2250           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2251         *yield = (Ustrcmp(coded, sub[1]+6) == 0) == testfor;
2252         }
2253       else if (sublen == 40)
2254         {
2255         int i;
2256         uschar coded[44];
2257         for (i = 0; i < 20; i++) sprintf(CS (coded+2*i), "%02X", digest[i]);
2258         coded[40] = 0;
2259         DEBUG(D_auth) debug_printf("crypteq: using SHA1+hex hashing\n"
2260           "  subject=%s\n  crypted=%s\n", coded, sub[1]+6);
2261         *yield = (strcmpic(coded, sub[1]+6) == 0) == testfor;
2262         }
2263       else
2264         {
2265         DEBUG(D_auth) debug_printf("crypteq: length for SHA-1 not 28 or 40: "
2266           "fail\n  crypted=%s\n", sub[1]+6);
2267         *yield = !testfor;
2268         }
2269       }
2270
2271     else   /* {crypt} or {crypt16} and non-{ at start */
2272       {
2273       int which = 0;
2274       uschar *coded;
2275
2276       if (strncmpic(sub[1], US"{crypt}", 7) == 0)
2277         {
2278         sub[1] += 7;
2279         which = 1;
2280         }
2281       else if (strncmpic(sub[1], US"{crypt16}", 9) == 0)
2282         {
2283         sub[1] += 9;
2284         which = 2;
2285         }
2286       else if (sub[1][0] == '{')
2287         {
2288         expand_string_message = string_sprintf("unknown encryption mechanism "
2289           "in \"%s\"", sub[1]);
2290         return NULL;
2291         }
2292
2293       switch(which)
2294         {
2295         case 0:  coded = US DEFAULT_CRYPT(CS sub[0], CS sub[1]); break;
2296         case 1:  coded = US crypt(CS sub[0], CS sub[1]); break;
2297         default: coded = US crypt16(CS sub[0], CS sub[1]); break;
2298         }
2299
2300       #define STR(s) # s
2301       #define XSTR(s) STR(s)
2302       DEBUG(D_auth) debug_printf("crypteq: using %s()\n"
2303         "  subject=%s\n  crypted=%s\n",
2304         (which == 0)? XSTR(DEFAULT_CRYPT) : (which == 1)? "crypt" : "crypt16",
2305         coded, sub[1]);
2306       #undef STR
2307       #undef XSTR
2308
2309       /* If the encrypted string contains fewer than two characters (for the
2310       salt), force failure. Otherwise we get false positives: with an empty
2311       string the yield of crypt() is an empty string! */
2312
2313       *yield = (Ustrlen(sub[1]) < 2)? !testfor :
2314         (Ustrcmp(coded, sub[1]) == 0) == testfor;
2315       }
2316     break;
2317     #endif  /* SUPPORT_CRYPTEQ */
2318     }   /* Switch for comparison conditions */
2319
2320   return s;    /* End of comparison conditions */
2321
2322
2323   /* and/or: computes logical and/or of several conditions */
2324
2325   case ECOND_AND:
2326   case ECOND_OR:
2327   subcondptr = (yield == NULL)? NULL : &tempcond;
2328   combined_cond = (cond_type == ECOND_AND);
2329
2330   while (isspace(*s)) s++;
2331   if (*s++ != '{') goto COND_FAILED_CURLY_START;
2332
2333   for (;;)
2334     {
2335     while (isspace(*s)) s++;
2336     if (*s == '}') break;
2337     if (*s != '{')
2338       {
2339       expand_string_message = string_sprintf("each subcondition "
2340         "inside an \"%s{...}\" condition must be in its own {}", name);
2341       return NULL;
2342       }
2343
2344     s = eval_condition(s+1, subcondptr);
2345     if (s == NULL)
2346       {
2347       expand_string_message = string_sprintf("%s inside \"%s{...}\" condition",
2348         expand_string_message, name);
2349       return NULL;
2350       }
2351     while (isspace(*s)) s++;
2352
2353     if (*s++ != '}')
2354       {
2355       expand_string_message = string_sprintf("missing } at end of condition "
2356         "inside \"%s\" group", name);
2357       return NULL;
2358       }
2359
2360     if (yield != NULL)
2361       {
2362       if (cond_type == ECOND_AND)
2363         {
2364         combined_cond &= tempcond;
2365         if (!combined_cond) subcondptr = NULL;  /* once false, don't */
2366         }                                       /* evaluate any more */
2367       else
2368         {
2369         combined_cond |= tempcond;
2370         if (combined_cond) subcondptr = NULL;   /* once true, don't */
2371         }                                       /* evaluate any more */
2372       }
2373     }
2374
2375   if (yield != NULL) *yield = (combined_cond == testfor);
2376   return ++s;
2377
2378
2379   /* forall/forany: iterates a condition with different values */
2380
2381   case ECOND_FORALL:
2382   case ECOND_FORANY:
2383     {
2384     int sep = 0;
2385     uschar *save_iterate_item = iterate_item;
2386
2387     while (isspace(*s)) s++;
2388     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2389     sub[0] = expand_string_internal(s, TRUE, &s, (yield == NULL));
2390     if (sub[0] == NULL) return NULL;
2391     if (*s++ != '}') goto COND_FAILED_CURLY_END;
2392
2393     while (isspace(*s)) s++;
2394     if (*s++ != '{') goto COND_FAILED_CURLY_START;
2395
2396     sub[1] = s;
2397
2398     /* Call eval_condition once, with result discarded (as if scanning a
2399     "false" part). This allows us to find the end of the condition, because if
2400     the list it empty, we won't actually evaluate the condition for real. */
2401
2402     s = eval_condition(sub[1], NULL);
2403     if (s == NULL)
2404       {
2405       expand_string_message = string_sprintf("%s inside \"%s\" condition",
2406         expand_string_message, name);
2407       return NULL;
2408       }
2409     while (isspace(*s)) s++;
2410
2411     if (*s++ != '}')
2412       {
2413       expand_string_message = string_sprintf("missing } at end of condition "
2414         "inside \"%s\"", name);
2415       return NULL;
2416       }
2417
2418     if (yield != NULL) *yield = !testfor;
2419     while ((iterate_item = string_nextinlist(&sub[0], &sep, NULL, 0)) != NULL)
2420       {
2421       DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
2422       if (eval_condition(sub[1], &tempcond) == NULL)
2423         {
2424         expand_string_message = string_sprintf("%s inside \"%s\" condition",
2425           expand_string_message, name);
2426         iterate_item = save_iterate_item;
2427         return NULL;
2428         }
2429       DEBUG(D_expand) debug_printf("%s: condition evaluated to %s\n", name,
2430         tempcond? "true":"false");
2431
2432       if (yield != NULL) *yield = (tempcond == testfor);
2433       if (tempcond == (cond_type == ECOND_FORANY)) break;
2434       }
2435
2436     iterate_item = save_iterate_item;
2437     return s;
2438     }
2439
2440
2441   /* Unknown condition */
2442
2443   default:
2444   expand_string_message = string_sprintf("unknown condition \"%s\"", name);
2445   return NULL;
2446   }   /* End switch on condition type */
2447
2448 /* Missing braces at start and end of data */
2449
2450 COND_FAILED_CURLY_START:
2451 expand_string_message = string_sprintf("missing { after \"%s\"", name);
2452 return NULL;
2453
2454 COND_FAILED_CURLY_END:
2455 expand_string_message = string_sprintf("missing } at end of \"%s\" condition",
2456   name);
2457 return NULL;
2458
2459 /* A condition requires code that is not compiled */
2460
2461 #if !defined(SUPPORT_PAM) || !defined(RADIUS_CONFIG_FILE) || \
2462     !defined(LOOKUP_LDAP) || !defined(CYRUS_PWCHECK_SOCKET) || \
2463     !defined(SUPPORT_CRYPTEQ) || !defined(CYRUS_SASLAUTHD_SOCKET)
2464 COND_FAILED_NOT_COMPILED:
2465 expand_string_message = string_sprintf("support for \"%s\" not compiled",
2466   name);
2467 return NULL;
2468 #endif
2469 }
2470
2471
2472
2473
2474 /*************************************************
2475 *          Save numerical variables              *
2476 *************************************************/
2477
2478 /* This function is called from items such as "if" that want to preserve and
2479 restore the numbered variables.
2480
2481 Arguments:
2482   save_expand_string    points to an array of pointers to set
2483   save_expand_nlength   points to an array of ints for the lengths
2484
2485 Returns:                the value of expand max to save
2486 */
2487
2488 static int
2489 save_expand_strings(uschar **save_expand_nstring, int *save_expand_nlength)
2490 {
2491 int i;
2492 for (i = 0; i <= expand_nmax; i++)
2493   {
2494   save_expand_nstring[i] = expand_nstring[i];
2495   save_expand_nlength[i] = expand_nlength[i];
2496   }
2497 return expand_nmax;
2498 }
2499
2500
2501
2502 /*************************************************
2503 *           Restore numerical variables          *
2504 *************************************************/
2505
2506 /* This function restored saved values of numerical strings.
2507
2508 Arguments:
2509   save_expand_nmax      the number of strings to restore
2510   save_expand_string    points to an array of pointers
2511   save_expand_nlength   points to an array of ints
2512
2513 Returns:                nothing
2514 */
2515
2516 static void
2517 restore_expand_strings(int save_expand_nmax, uschar **save_expand_nstring,
2518   int *save_expand_nlength)
2519 {
2520 int i;
2521 expand_nmax = save_expand_nmax;
2522 for (i = 0; i <= expand_nmax; i++)
2523   {
2524   expand_nstring[i] = save_expand_nstring[i];
2525   expand_nlength[i] = save_expand_nlength[i];
2526   }
2527 }
2528
2529
2530
2531
2532
2533 /*************************************************
2534 *            Handle yes/no substrings            *
2535 *************************************************/
2536
2537 /* This function is used by ${if}, ${lookup} and ${extract} to handle the
2538 alternative substrings that depend on whether or not the condition was true,
2539 or the lookup or extraction succeeded. The substrings always have to be
2540 expanded, to check their syntax, but "skipping" is set when the result is not
2541 needed - this avoids unnecessary nested lookups.
2542
2543 Arguments:
2544   skipping       TRUE if we were skipping when this item was reached
2545   yes            TRUE if the first string is to be used, else use the second
2546   save_lookup    a value to put back into lookup_value before the 2nd expansion
2547   sptr           points to the input string pointer
2548   yieldptr       points to the output string pointer
2549   sizeptr        points to the output string size
2550   ptrptr         points to the output string pointer
2551   type           "lookup" or "if" or "extract" or "run", for error message
2552
2553 Returns:         0 OK; lookup_value has been reset to save_lookup
2554                  1 expansion failed
2555                  2 expansion failed because of bracketing error
2556 */
2557
2558 static int
2559 process_yesno(BOOL skipping, BOOL yes, uschar *save_lookup, uschar **sptr,
2560   uschar **yieldptr, int *sizeptr, int *ptrptr, uschar *type)
2561 {
2562 int rc = 0;
2563 uschar *s = *sptr;    /* Local value */
2564 uschar *sub1, *sub2;
2565
2566 /* If there are no following strings, we substitute the contents of $value for
2567 lookups and for extractions in the success case. For the ${if item, the string
2568 "true" is substituted. In the fail case, nothing is substituted for all three
2569 items. */
2570
2571 while (isspace(*s)) s++;
2572 if (*s == '}')
2573   {
2574   if (type[0] == 'i')
2575     {
2576     if (yes) *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, US"true", 4);
2577     }
2578   else
2579     {
2580     if (yes && lookup_value != NULL)
2581       *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, lookup_value,
2582         Ustrlen(lookup_value));
2583     lookup_value = save_lookup;
2584     }
2585   s++;
2586   goto RETURN;
2587   }
2588
2589 /* The first following string must be braced. */
2590
2591 if (*s++ != '{') goto FAILED_CURLY;
2592
2593 /* Expand the first substring. Forced failures are noticed only if we actually
2594 want this string. Set skipping in the call in the fail case (this will always
2595 be the case if we were already skipping). */
2596
2597 sub1 = expand_string_internal(s, TRUE, &s, !yes);
2598 if (sub1 == NULL && (yes || !expand_string_forcedfail)) goto FAILED;
2599 expand_string_forcedfail = FALSE;
2600 if (*s++ != '}') goto FAILED_CURLY;
2601
2602 /* If we want the first string, add it to the output */
2603
2604 if (yes)
2605   *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub1, Ustrlen(sub1));
2606
2607 /* If this is called from a lookup or an extract, we want to restore $value to
2608 what it was at the start of the item, so that it has this value during the
2609 second string expansion. For the call from "if" or "run" to this function,
2610 save_lookup is set to lookup_value, so that this statement does nothing. */
2611
2612 lookup_value = save_lookup;
2613
2614 /* There now follows either another substring, or "fail", or nothing. This
2615 time, forced failures are noticed only if we want the second string. We must
2616 set skipping in the nested call if we don't want this string, or if we were
2617 already skipping. */
2618
2619 while (isspace(*s)) s++;
2620 if (*s == '{')
2621   {
2622   sub2 = expand_string_internal(s+1, TRUE, &s, yes || skipping);
2623   if (sub2 == NULL && (!yes || !expand_string_forcedfail)) goto FAILED;
2624   expand_string_forcedfail = FALSE;
2625   if (*s++ != '}') goto FAILED_CURLY;
2626
2627   /* If we want the second string, add it to the output */
2628
2629   if (!yes)
2630     *yieldptr = string_cat(*yieldptr, sizeptr, ptrptr, sub2, Ustrlen(sub2));
2631   }
2632
2633 /* If there is no second string, but the word "fail" is present when the use of
2634 the second string is wanted, set a flag indicating it was a forced failure
2635 rather than a syntactic error. Swallow the terminating } in case this is nested
2636 inside another lookup or if or extract. */
2637
2638 else if (*s != '}')
2639   {
2640   uschar name[256];
2641   s = read_name(name, sizeof(name), s, US"_");
2642   if (Ustrcmp(name, "fail") == 0)
2643     {
2644     if (!yes && !skipping)
2645       {
2646       while (isspace(*s)) s++;
2647       if (*s++ != '}') goto FAILED_CURLY;
2648       expand_string_message =
2649         string_sprintf("\"%s\" failed and \"fail\" requested", type);
2650       expand_string_forcedfail = TRUE;
2651       goto FAILED;
2652       }
2653     }
2654   else
2655     {
2656     expand_string_message =
2657       string_sprintf("syntax error in \"%s\" item - \"fail\" expected", type);
2658     goto FAILED;
2659     }
2660   }
2661
2662 /* All we have to do now is to check on the final closing brace. */
2663
2664 while (isspace(*s)) s++;
2665 if (*s++ == '}') goto RETURN;
2666
2667 /* Get here if there is a bracketing failure */
2668
2669 FAILED_CURLY:
2670 rc++;
2671
2672 /* Get here for other failures */
2673
2674 FAILED:
2675 rc++;
2676
2677 /* Update the input pointer value before returning */
2678
2679 RETURN:
2680 *sptr = s;
2681 return rc;
2682 }
2683
2684
2685
2686
2687 /*************************************************
2688 *    Handle MD5 or SHA-1 computation for HMAC    *
2689 *************************************************/
2690
2691 /* These are some wrapping functions that enable the HMAC code to be a bit
2692 cleaner. A good compiler will spot the tail recursion.
2693
2694 Arguments:
2695   type         HMAC_MD5 or HMAC_SHA1
2696   remaining    are as for the cryptographic hash functions
2697
2698 Returns:       nothing
2699 */
2700
2701 static void
2702 chash_start(int type, void *base)
2703 {
2704 if (type == HMAC_MD5)
2705   md5_start((md5 *)base);
2706 else
2707   sha1_start((sha1 *)base);
2708 }
2709
2710 static void
2711 chash_mid(int type, void *base, uschar *string)
2712 {
2713 if (type == HMAC_MD5)
2714   md5_mid((md5 *)base, string);
2715 else
2716   sha1_mid((sha1 *)base, string);
2717 }
2718
2719 static void
2720 chash_end(int type, void *base, uschar *string, int length, uschar *digest)
2721 {
2722 if (type == HMAC_MD5)
2723   md5_end((md5 *)base, string, length, digest);
2724 else
2725   sha1_end((sha1 *)base, string, length, digest);
2726 }
2727
2728
2729
2730
2731
2732 /********************************************************
2733 * prvs: Get last three digits of days since Jan 1, 1970 *
2734 ********************************************************/
2735
2736 /* This is needed to implement the "prvs" BATV reverse
2737    path signing scheme
2738
2739 Argument: integer "days" offset to add or substract to
2740           or from the current number of days.
2741
2742 Returns:  pointer to string containing the last three
2743           digits of the number of days since Jan 1, 1970,
2744           modified by the offset argument, NULL if there
2745           was an error in the conversion.
2746
2747 */
2748
2749 static uschar *
2750 prvs_daystamp(int day_offset)
2751 {
2752 uschar *days = store_get(32);                /* Need at least 24 for cases */
2753 (void)string_format(days, 32, TIME_T_FMT,    /* where TIME_T_FMT is %lld */
2754   (time(NULL) + day_offset*86400)/86400);
2755 return (Ustrlen(days) >= 3) ? &days[Ustrlen(days)-3] : US"100";
2756 }
2757
2758
2759
2760 /********************************************************
2761 *   prvs: perform HMAC-SHA1 computation of prvs bits    *
2762 ********************************************************/
2763
2764 /* This is needed to implement the "prvs" BATV reverse
2765    path signing scheme
2766
2767 Arguments:
2768   address RFC2821 Address to use
2769       key The key to use (must be less than 64 characters
2770           in size)
2771   key_num Single-digit key number to use. Defaults to
2772           '0' when NULL.
2773
2774 Returns:  pointer to string containing the first three
2775           bytes of the final hash in hex format, NULL if
2776           there was an error in the process.
2777 */
2778
2779 static uschar *
2780 prvs_hmac_sha1(uschar *address, uschar *key, uschar *key_num, uschar *daystamp)
2781 {
2782 uschar *hash_source, *p;
2783 int size = 0,offset = 0,i;
2784 sha1 sha1_base;
2785 void *use_base = &sha1_base;
2786 uschar innerhash[20];
2787 uschar finalhash[20];
2788 uschar innerkey[64];
2789 uschar outerkey[64];
2790 uschar *finalhash_hex = store_get(40);
2791
2792 if (key_num == NULL)
2793   key_num = US"0";
2794
2795 if (Ustrlen(key) > 64)
2796   return NULL;
2797
2798 hash_source = string_cat(NULL,&size,&offset,key_num,1);
2799 string_cat(hash_source,&size,&offset,daystamp,3);
2800 string_cat(hash_source,&size,&offset,address,Ustrlen(address));
2801 hash_source[offset] = '\0';
2802
2803 DEBUG(D_expand) debug_printf("prvs: hash source is '%s'\n", hash_source);
2804
2805 memset(innerkey, 0x36, 64);
2806 memset(outerkey, 0x5c, 64);
2807
2808 for (i = 0; i < Ustrlen(key); i++)
2809   {
2810   innerkey[i] ^= key[i];
2811   outerkey[i] ^= key[i];
2812   }
2813
2814 chash_start(HMAC_SHA1, use_base);
2815 chash_mid(HMAC_SHA1, use_base, innerkey);
2816 chash_end(HMAC_SHA1, use_base, hash_source, offset, innerhash);
2817
2818 chash_start(HMAC_SHA1, use_base);
2819 chash_mid(HMAC_SHA1, use_base, outerkey);
2820 chash_end(HMAC_SHA1, use_base, innerhash, 20, finalhash);
2821
2822 p = finalhash_hex;
2823 for (i = 0; i < 3; i++)
2824   {
2825   *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
2826   *p++ = hex_digits[finalhash[i] & 0x0f];
2827   }
2828 *p = '\0';
2829
2830 return finalhash_hex;
2831 }
2832
2833
2834
2835
2836 /*************************************************
2837 *        Join a file onto the output string      *
2838 *************************************************/
2839
2840 /* This is used for readfile and after a run expansion. It joins the contents
2841 of a file onto the output string, globally replacing newlines with a given
2842 string (optionally). The file is closed at the end.
2843
2844 Arguments:
2845   f            the FILE
2846   yield        pointer to the expandable string
2847   sizep        pointer to the current size
2848   ptrp         pointer to the current position
2849   eol          newline replacement string, or NULL
2850
2851 Returns:       new value of string pointer
2852 */
2853
2854 static uschar *
2855 cat_file(FILE *f, uschar *yield, int *sizep, int *ptrp, uschar *eol)
2856 {
2857 int eollen;
2858 uschar buffer[1024];
2859
2860 eollen = (eol == NULL)? 0 : Ustrlen(eol);
2861
2862 while (Ufgets(buffer, sizeof(buffer), f) != NULL)
2863   {
2864   int len = Ustrlen(buffer);
2865   if (eol != NULL && buffer[len-1] == '\n') len--;
2866   yield = string_cat(yield, sizep, ptrp, buffer, len);
2867   if (buffer[len] != 0)
2868     yield = string_cat(yield, sizep, ptrp, eol, eollen);
2869   }
2870
2871 if (yield != NULL) yield[*ptrp] = 0;
2872
2873 return yield;
2874 }
2875
2876
2877
2878
2879 /*************************************************
2880 *          Evaluate numeric expression           *
2881 *************************************************/
2882
2883 /* This is a set of mutually recursive functions that evaluate an arithmetic
2884 expression involving + - * / % & | ^ ~ << >> and parentheses. The only one of
2885 these functions that is called from elsewhere is eval_expr, whose interface is:
2886
2887 Arguments:
2888   sptr        pointer to the pointer to the string - gets updated
2889   decimal     TRUE if numbers are to be assumed decimal
2890   error       pointer to where to put an error message - must be NULL on input
2891   endket      TRUE if ')' must terminate - FALSE for external call
2892
2893 Returns:      on success: the value of the expression, with *error still NULL
2894               on failure: an undefined value, with *error = a message
2895 */
2896
2897 static int eval_op_or(uschar **, BOOL, uschar **);
2898
2899
2900 static int
2901 eval_expr(uschar **sptr, BOOL decimal, uschar **error, BOOL endket)
2902 {
2903 uschar *s = *sptr;
2904 int x = eval_op_or(&s, decimal, error);
2905 if (*error == NULL)
2906   {
2907   if (endket)
2908     {
2909     if (*s != ')')
2910       *error = US"expecting closing parenthesis";
2911     else
2912       while (isspace(*(++s)));
2913     }
2914   else if (*s != 0) *error = US"expecting operator";
2915   }
2916 *sptr = s;
2917 return x;
2918 }
2919
2920
2921 static int
2922 eval_number(uschar **sptr, BOOL decimal, uschar **error)
2923 {
2924 register int c;
2925 int n;
2926 uschar *s = *sptr;
2927 while (isspace(*s)) s++;
2928 c = *s;
2929 if (isdigit(c))
2930   {
2931   int count;
2932   (void)sscanf(CS s, (decimal? "%d%n" : "%i%n"), &n, &count);
2933   s += count;
2934   if (tolower(*s) == 'k') { n *= 1024; s++; }
2935     else if (tolower(*s) == 'm') { n *= 1024*1024; s++; }
2936   while (isspace (*s)) s++;
2937   }
2938 else if (c == '(')
2939   {
2940   s++;
2941   n = eval_expr(&s, decimal, error, 1);
2942   }
2943 else
2944   {
2945   *error = US"expecting number or opening parenthesis";
2946   n = 0;
2947   }
2948 *sptr = s;
2949 return n;
2950 }
2951
2952
2953 static int eval_op_unary(uschar **sptr, BOOL decimal, uschar **error)
2954 {
2955 uschar *s = *sptr;
2956 int x;
2957 while (isspace(*s)) s++;
2958 if (*s == '+' || *s == '-' || *s == '~')
2959   {
2960   int op = *s++;
2961   x = eval_op_unary(&s, decimal, error);
2962   if (op == '-') x = -x;
2963     else if (op == '~') x = ~x;
2964   }
2965 else
2966   {
2967   x = eval_number(&s, decimal, error);
2968   }
2969 *sptr = s;
2970 return x;
2971 }
2972
2973
2974 static int eval_op_mult(uschar **sptr, BOOL decimal, uschar **error)
2975 {
2976 uschar *s = *sptr;
2977 int x = eval_op_unary(&s, decimal, error);
2978 if (*error == NULL)
2979   {
2980   while (*s == '*' || *s == '/' || *s == '%')
2981     {
2982     int op = *s++;
2983     int y = eval_op_unary(&s, decimal, error);
2984     if (*error != NULL) break;
2985     if (op == '*') x *= y;
2986       else if (op == '/') x /= y;
2987       else x %= y;
2988     }
2989   }
2990 *sptr = s;
2991 return x;
2992 }
2993
2994
2995 static int eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
2996 {
2997 uschar *s = *sptr;
2998 int x = eval_op_mult(&s, decimal, error);
2999 if (*error == NULL)
3000   {
3001   while (*s == '+' || *s == '-')
3002     {
3003     int op = *s++;
3004     int y = eval_op_mult(&s, decimal, error);
3005     if (*error != NULL) break;
3006     if (op == '+') x += y; else x -= y;
3007     }
3008   }
3009 *sptr = s;
3010 return x;
3011 }
3012
3013
3014 static int eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
3015 {
3016 uschar *s = *sptr;
3017 int x = eval_op_sum(&s, decimal, error);
3018 if (*error == NULL)
3019   {
3020   while ((*s == '<' || *s == '>') && s[1] == s[0])
3021     {
3022     int y;
3023     int op = *s++;
3024     s++;
3025     y = eval_op_sum(&s, decimal, error);
3026     if (*error != NULL) break;
3027     if (op == '<') x <<= y; else x >>= y;
3028     }
3029   }
3030 *sptr = s;
3031 return x;
3032 }
3033
3034
3035 static int eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
3036 {
3037 uschar *s = *sptr;
3038 int x = eval_op_shift(&s, decimal, error);
3039 if (*error == NULL)
3040   {
3041   while (*s == '&')
3042     {
3043     int y;
3044     s++;
3045     y = eval_op_shift(&s, decimal, error);
3046     if (*error != NULL) break;
3047     x &= y;
3048     }
3049   }
3050 *sptr = s;
3051 return x;
3052 }
3053
3054
3055 static int eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
3056 {
3057 uschar *s = *sptr;
3058 int x = eval_op_and(&s, decimal, error);
3059 if (*error == NULL)
3060   {
3061   while (*s == '^')
3062     {
3063     int y;
3064     s++;
3065     y = eval_op_and(&s, decimal, error);
3066     if (*error != NULL) break;
3067     x ^= y;
3068     }
3069   }
3070 *sptr = s;
3071 return x;
3072 }
3073
3074
3075 static int eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
3076 {
3077 uschar *s = *sptr;
3078 int x = eval_op_xor(&s, decimal, error);
3079 if (*error == NULL)
3080   {
3081   while (*s == '|')
3082     {
3083     int y;
3084     s++;
3085     y = eval_op_xor(&s, decimal, error);
3086     if (*error != NULL) break;
3087     x |= y;
3088     }
3089   }
3090 *sptr = s;
3091 return x;
3092 }
3093
3094
3095
3096 /*************************************************
3097 *                 Expand string                  *
3098 *************************************************/
3099
3100 /* Returns either an unchanged string, or the expanded string in stacking pool
3101 store. Interpreted sequences are:
3102
3103    \...                    normal escaping rules
3104    $name                   substitutes the variable
3105    ${name}                 ditto
3106    ${op:string}            operates on the expanded string value
3107    ${item{arg1}{arg2}...}  expands the args and then does the business
3108                              some literal args are not enclosed in {}
3109
3110 There are now far too many operators and item types to make it worth listing
3111 them here in detail any more.
3112
3113 We use an internal routine recursively to handle embedded substrings. The
3114 external function follows. The yield is NULL if the expansion failed, and there
3115 are two cases: if something collapsed syntactically, or if "fail" was given
3116 as the action on a lookup failure. These can be distinguised by looking at the
3117 variable expand_string_forcedfail, which is TRUE in the latter case.
3118
3119 The skipping flag is set true when expanding a substring that isn't actually
3120 going to be used (after "if" or "lookup") and it prevents lookups from
3121 happening lower down.
3122
3123 Store usage: At start, a store block of the length of the input plus 64
3124 is obtained. This is expanded as necessary by string_cat(), which might have to
3125 get a new block, or might be able to expand the original. At the end of the
3126 function we can release any store above that portion of the yield block that
3127 was actually used. In many cases this will be optimal.
3128
3129 However: if the first item in the expansion is a variable name or header name,
3130 we reset the store before processing it; if the result is in fresh store, we
3131 use that without copying. This is helpful for expanding strings like
3132 $message_headers which can get very long.
3133
3134 Arguments:
3135   string         the string to be expanded
3136   ket_ends       true if expansion is to stop at }
3137   left           if not NULL, a pointer to the first character after the
3138                  expansion is placed here (typically used with ket_ends)
3139   skipping       TRUE for recursive calls when the value isn't actually going
3140                  to be used (to allow for optimisation)
3141
3142 Returns:         NULL if expansion fails:
3143                    expand_string_forcedfail is set TRUE if failure was forced
3144                    expand_string_message contains a textual error message
3145                  a pointer to the expanded string on success
3146 */
3147
3148 static uschar *
3149 expand_string_internal(uschar *string, BOOL ket_ends, uschar **left,
3150   BOOL skipping)
3151 {
3152 int ptr = 0;
3153 int size = Ustrlen(string)+ 64;
3154 int item_type;
3155 uschar *yield = store_get(size);
3156 uschar *s = string;
3157 uschar *save_expand_nstring[EXPAND_MAXN+1];
3158 int save_expand_nlength[EXPAND_MAXN+1];
3159
3160 expand_string_forcedfail = FALSE;
3161 expand_string_message = US"";
3162
3163 while (*s != 0)
3164   {
3165   uschar *value;
3166   uschar name[256];
3167
3168   /* \ escapes the next character, which must exist, or else
3169   the expansion fails. There's a special escape, \N, which causes
3170   copying of the subject verbatim up to the next \N. Otherwise,
3171   the escapes are the standard set. */
3172
3173   if (*s == '\\')
3174     {
3175     if (s[1] == 0)
3176       {
3177       expand_string_message = US"\\ at end of string";
3178       goto EXPAND_FAILED;
3179       }
3180
3181     if (s[1] == 'N')
3182       {
3183       uschar *t = s + 2;
3184       for (s = t; *s != 0; s++) if (*s == '\\' && s[1] == 'N') break;
3185       yield = string_cat(yield, &size, &ptr, t, s - t);
3186       if (*s != 0) s += 2;
3187       }
3188
3189     else
3190       {
3191       uschar ch[1];
3192       ch[0] = string_interpret_escape(&s);
3193       s++;
3194       yield = string_cat(yield, &size, &ptr, ch, 1);
3195       }
3196
3197     continue;
3198     }
3199
3200   /* Anything other than $ is just copied verbatim, unless we are
3201   looking for a terminating } character. */
3202
3203   if (ket_ends && *s == '}') break;
3204
3205   if (*s != '$')
3206     {
3207     yield = string_cat(yield, &size, &ptr, s++, 1);
3208     continue;
3209     }
3210
3211   /* No { after the $ - must be a plain name or a number for string
3212   match variable. There has to be a fudge for variables that are the
3213   names of header fields preceded by "$header_" because header field
3214   names can contain any printing characters except space and colon.
3215   For those that don't like typing this much, "$h_" is a synonym for
3216   "$header_". A non-existent header yields a NULL value; nothing is
3217   inserted. */
3218
3219   if (isalpha((*(++s))))
3220     {
3221     int len;
3222     int newsize = 0;
3223
3224     s = read_name(name, sizeof(name), s, US"_");
3225
3226     /* If this is the first thing to be expanded, release the pre-allocated
3227     buffer. */
3228
3229     if (ptr == 0 && yield != NULL)
3230       {
3231       store_reset(yield);
3232       yield = NULL;
3233       size = 0;
3234       }
3235
3236     /* Header */
3237
3238     if (Ustrncmp(name, "h_", 2) == 0 ||
3239         Ustrncmp(name, "rh_", 3) == 0 ||
3240         Ustrncmp(name, "bh_", 3) == 0 ||
3241         Ustrncmp(name, "header_", 7) == 0 ||
3242         Ustrncmp(name, "rheader_", 8) == 0 ||
3243         Ustrncmp(name, "bheader_", 8) == 0)
3244       {
3245       BOOL want_raw = (name[0] == 'r')? TRUE : FALSE;
3246       uschar *charset = (name[0] == 'b')? NULL : headers_charset;
3247       s = read_header_name(name, sizeof(name), s);
3248       value = find_header(name, FALSE, &newsize, want_raw, charset);
3249
3250       /* If we didn't find the header, and the header contains a closing brace
3251       character, this may be a user error where the terminating colon
3252       has been omitted. Set a flag to adjust the error message in this case.
3253       But there is no error here - nothing gets inserted. */
3254
3255       if (value == NULL)
3256         {
3257         if (Ustrchr(name, '}') != NULL) malformed_header = TRUE;
3258         continue;
3259         }
3260       }
3261
3262     /* Variable */
3263
3264     else
3265       {
3266       value = find_variable(name, FALSE, skipping, &newsize);
3267       if (value == NULL)
3268         {
3269         expand_string_message =
3270           string_sprintf("unknown variable name \"%s\"", name);
3271           check_variable_error_message(name);
3272         goto EXPAND_FAILED;
3273         }
3274       }
3275
3276     /* If the data is known to be in a new buffer, newsize will be set to the
3277     size of that buffer. If this is the first thing in an expansion string,
3278     yield will be NULL; just point it at the new store instead of copying. Many
3279     expansion strings contain just one reference, so this is a useful
3280     optimization, especially for humungous headers. */
3281
3282     len = Ustrlen(value);
3283     if (yield == NULL && newsize != 0)
3284       {
3285       yield = value;
3286       size = newsize;
3287       ptr = len;
3288       }
3289     else yield = string_cat(yield, &size, &ptr, value, len);
3290
3291     continue;
3292     }
3293
3294   if (isdigit(*s))
3295     {
3296     int n;
3297     s = read_number(&n, s);
3298     if (n >= 0 && n <= expand_nmax)
3299       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3300         expand_nlength[n]);
3301     continue;
3302     }
3303
3304   /* Otherwise, if there's no '{' after $ it's an error. */
3305
3306   if (*s != '{')
3307     {
3308     expand_string_message = US"$ not followed by letter, digit, or {";
3309     goto EXPAND_FAILED;
3310     }
3311
3312   /* After { there can be various things, but they all start with
3313   an initial word, except for a number for a string match variable. */
3314
3315   if (isdigit((*(++s))))
3316     {
3317     int n;
3318     s = read_number(&n, s);
3319     if (*s++ != '}')
3320       {
3321       expand_string_message = US"} expected after number";
3322       goto EXPAND_FAILED;
3323       }
3324     if (n >= 0 && n <= expand_nmax)
3325       yield = string_cat(yield, &size, &ptr, expand_nstring[n],
3326         expand_nlength[n]);
3327     continue;
3328     }
3329
3330   if (!isalpha(*s))
3331     {
3332     expand_string_message = US"letter or digit expected after ${";
3333     goto EXPAND_FAILED;
3334     }
3335
3336   /* Allow "-" in names to cater for substrings with negative
3337   arguments. Since we are checking for known names after { this is
3338   OK. */
3339
3340   s = read_name(name, sizeof(name), s, US"_-");
3341   item_type = chop_match(name, item_table, sizeof(item_table)/sizeof(uschar *));
3342
3343   switch(item_type)
3344     {
3345     /* Handle conditionals - preserve the values of the numerical expansion
3346     variables in case they get changed by a regular expression match in the
3347     condition. If not, they retain their external settings. At the end
3348     of this "if" section, they get restored to their previous values. */
3349
3350     case EITEM_IF:
3351       {
3352       BOOL cond = FALSE;
3353       uschar *next_s;
3354       int save_expand_nmax =
3355         save_expand_strings(save_expand_nstring, save_expand_nlength);
3356
3357       while (isspace(*s)) s++;
3358       next_s = eval_condition(s, skipping? NULL : &cond);
3359       if (next_s == NULL) goto EXPAND_FAILED;  /* message already set */
3360
3361       DEBUG(D_expand)
3362         debug_printf("condition: %.*s\n   result: %s\n", (int)(next_s - s), s,
3363           cond? "true" : "false");
3364
3365       s = next_s;
3366
3367       /* The handling of "yes" and "no" result strings is now in a separate
3368       function that is also used by ${lookup} and ${extract} and ${run}. */
3369
3370       switch(process_yesno(
3371                skipping,                     /* were previously skipping */
3372                cond,                         /* success/failure indicator */
3373                lookup_value,                 /* value to reset for string2 */
3374                &s,                           /* input pointer */
3375                &yield,                       /* output pointer */
3376                &size,                        /* output size */
3377                &ptr,                         /* output current point */
3378                US"if"))                      /* condition type */
3379         {
3380         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3381         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3382         }
3383
3384       /* Restore external setting of expansion variables for continuation
3385       at this level. */
3386
3387       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3388         save_expand_nlength);
3389       continue;
3390       }
3391
3392     /* Handle database lookups unless locked out. If "skipping" is TRUE, we are
3393     expanding an internal string that isn't actually going to be used. All we
3394     need to do is check the syntax, so don't do a lookup at all. Preserve the
3395     values of the numerical expansion variables in case they get changed by a
3396     partial lookup. If not, they retain their external settings. At the end
3397     of this "lookup" section, they get restored to their previous values. */
3398
3399     case EITEM_LOOKUP:
3400       {
3401       int stype, partial, affixlen, starflags;
3402       int expand_setup = 0;
3403       int nameptr = 0;
3404       uschar *key, *filename, *affix;
3405       uschar *save_lookup_value = lookup_value;
3406       int save_expand_nmax =
3407         save_expand_strings(save_expand_nstring, save_expand_nlength);
3408
3409       if ((expand_forbid & RDO_LOOKUP) != 0)
3410         {
3411         expand_string_message = US"lookup expansions are not permitted";
3412         goto EXPAND_FAILED;
3413         }
3414
3415       /* Get the key we are to look up for single-key+file style lookups.
3416       Otherwise set the key NULL pro-tem. */
3417
3418       while (isspace(*s)) s++;
3419       if (*s == '{')
3420         {
3421         key = expand_string_internal(s+1, TRUE, &s, skipping);
3422         if (key == NULL) goto EXPAND_FAILED;
3423         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3424         while (isspace(*s)) s++;
3425         }
3426       else key = NULL;
3427
3428       /* Find out the type of database */
3429
3430       if (!isalpha(*s))
3431         {
3432         expand_string_message = US"missing lookup type";
3433         goto EXPAND_FAILED;
3434         }
3435
3436       /* The type is a string that may contain special characters of various
3437       kinds. Allow everything except space or { to appear; the actual content
3438       is checked by search_findtype_partial. */
3439
3440       while (*s != 0 && *s != '{' && !isspace(*s))
3441         {
3442         if (nameptr < sizeof(name) - 1) name[nameptr++] = *s;
3443         s++;
3444         }
3445       name[nameptr] = 0;
3446       while (isspace(*s)) s++;
3447
3448       /* Now check for the individual search type and any partial or default
3449       options. Only those types that are actually in the binary are valid. */
3450
3451       stype = search_findtype_partial(name, &partial, &affix, &affixlen,
3452         &starflags);
3453       if (stype < 0)
3454         {
3455         expand_string_message = search_error_message;
3456         goto EXPAND_FAILED;
3457         }
3458
3459       /* Check that a key was provided for those lookup types that need it,
3460       and was not supplied for those that use the query style. */
3461
3462       if (!mac_islookup(stype, lookup_querystyle|lookup_absfilequery))
3463         {
3464         if (key == NULL)
3465           {
3466           expand_string_message = string_sprintf("missing {key} for single-"
3467             "key \"%s\" lookup", name);
3468           goto EXPAND_FAILED;
3469           }
3470         }
3471       else
3472         {
3473         if (key != NULL)
3474           {
3475           expand_string_message = string_sprintf("a single key was given for "
3476             "lookup type \"%s\", which is not a single-key lookup type", name);
3477           goto EXPAND_FAILED;
3478           }
3479         }
3480
3481       /* Get the next string in brackets and expand it. It is the file name for
3482       single-key+file lookups, and the whole query otherwise. In the case of
3483       queries that also require a file name (e.g. sqlite), the file name comes
3484       first. */
3485
3486       if (*s != '{') goto EXPAND_FAILED_CURLY;
3487       filename = expand_string_internal(s+1, TRUE, &s, skipping);
3488       if (filename == NULL) goto EXPAND_FAILED;
3489       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
3490       while (isspace(*s)) s++;
3491
3492       /* If this isn't a single-key+file lookup, re-arrange the variables
3493       to be appropriate for the search_ functions. For query-style lookups,
3494       there is just a "key", and no file name. For the special query-style +
3495       file types, the query (i.e. "key") starts with a file name. */
3496
3497       if (key == NULL)
3498         {
3499         while (isspace(*filename)) filename++;
3500         key = filename;
3501
3502         if (mac_islookup(stype, lookup_querystyle))
3503           {
3504           filename = NULL;
3505           }
3506         else
3507           {
3508           if (*filename != '/')
3509             {
3510             expand_string_message = string_sprintf(
3511               "absolute file name expected for \"%s\" lookup", name);
3512             goto EXPAND_FAILED;
3513             }
3514           while (*key != 0 && !isspace(*key)) key++;
3515           if (*key != 0) *key++ = 0;
3516           }
3517         }
3518
3519       /* If skipping, don't do the next bit - just lookup_value == NULL, as if
3520       the entry was not found. Note that there is no search_close() function.
3521       Files are left open in case of re-use. At suitable places in higher logic,
3522       search_tidyup() is called to tidy all open files. This can save opening
3523       the same file several times. However, files may also get closed when
3524       others are opened, if too many are open at once. The rule is that a
3525       handle should not be used after a second search_open().
3526
3527       Request that a partial search sets up $1 and maybe $2 by passing
3528       expand_setup containing zero. If its value changes, reset expand_nmax,
3529       since new variables will have been set. Note that at the end of this
3530       "lookup" section, the old numeric variables are restored. */
3531
3532       if (skipping)
3533         lookup_value = NULL;
3534       else
3535         {
3536         void *handle = search_open(filename, stype, 0, NULL, NULL);
3537         if (handle == NULL)
3538           {
3539           expand_string_message = search_error_message;
3540           goto EXPAND_FAILED;
3541           }
3542         lookup_value = search_find(handle, filename, key, partial, affix,
3543           affixlen, starflags, &expand_setup);
3544         if (search_find_defer)
3545           {
3546           expand_string_message =
3547             string_sprintf("lookup of \"%s\" gave DEFER: %s", key,
3548               search_error_message);
3549           goto EXPAND_FAILED;
3550           }
3551         if (expand_setup > 0) expand_nmax = expand_setup;
3552         }
3553
3554       /* The handling of "yes" and "no" result strings is now in a separate
3555       function that is also used by ${if} and ${extract}. */
3556
3557       switch(process_yesno(
3558                skipping,                     /* were previously skipping */
3559                lookup_value != NULL,         /* success/failure indicator */
3560                save_lookup_value,            /* value to reset for string2 */
3561                &s,                           /* input pointer */
3562                &yield,                       /* output pointer */
3563                &size,                        /* output size */
3564                &ptr,                         /* output current point */
3565                US"lookup"))                  /* condition type */
3566         {
3567         case 1: goto EXPAND_FAILED;          /* when all is well, the */
3568         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
3569         }
3570
3571       /* Restore external setting of expansion variables for carrying on
3572       at this level, and continue. */
3573
3574       restore_expand_strings(save_expand_nmax, save_expand_nstring,
3575         save_expand_nlength);
3576       continue;
3577       }
3578
3579     /* If Perl support is configured, handle calling embedded perl subroutines,
3580     unless locked out at this time. Syntax is ${perl{sub}} or ${perl{sub}{arg}}
3581     or ${perl{sub}{arg1}{arg2}} or up to a maximum of EXIM_PERL_MAX_ARGS
3582     arguments (defined below). */
3583
3584     #define EXIM_PERL_MAX_ARGS 8
3585
3586     case EITEM_PERL:
3587     #ifndef EXIM_PERL
3588     expand_string_message = US"\"${perl\" encountered, but this facility "
3589       "is not included in this binary";
3590     goto EXPAND_FAILED;
3591
3592     #else   /* EXIM_PERL */
3593       {
3594       uschar *sub_arg[EXIM_PERL_MAX_ARGS + 2];
3595       uschar *new_yield;
3596
3597       if ((expand_forbid & RDO_PERL) != 0)
3598         {
3599         expand_string_message = US"Perl calls are not permitted";
3600         goto EXPAND_FAILED;
3601         }
3602
3603       switch(read_subs(sub_arg, EXIM_PERL_MAX_ARGS + 1, 1, &s, skipping, TRUE,
3604            US"perl"))
3605         {
3606         case 1: goto EXPAND_FAILED_CURLY;
3607         case 2:
3608         case 3: goto EXPAND_FAILED;
3609         }
3610
3611       /* If skipping, we don't actually do anything */
3612
3613       if (skipping) continue;
3614
3615       /* Start the interpreter if necessary */
3616
3617       if (!opt_perl_started)
3618         {
3619         uschar *initerror;
3620         if (opt_perl_startup == NULL)
3621           {
3622           expand_string_message = US"A setting of perl_startup is needed when "
3623             "using the Perl interpreter";
3624           goto EXPAND_FAILED;
3625           }
3626         DEBUG(D_any) debug_printf("Starting Perl interpreter\n");
3627         initerror = init_perl(opt_perl_startup);
3628         if (initerror != NULL)
3629           {
3630           expand_string_message =
3631             string_sprintf("error in perl_startup code: %s\n", initerror);
3632           goto EXPAND_FAILED;
3633           }
3634         opt_perl_started = TRUE;
3635         }
3636
3637       /* Call the function */
3638
3639       sub_arg[EXIM_PERL_MAX_ARGS + 1] = NULL;
3640       new_yield = call_perl_cat(yield, &size, &ptr, &expand_string_message,
3641         sub_arg[0], sub_arg + 1);
3642
3643       /* NULL yield indicates failure; if the message pointer has been set to
3644       NULL, the yield was undef, indicating a forced failure. Otherwise the
3645       message will indicate some kind of Perl error. */
3646
3647       if (new_yield == NULL)
3648         {
3649         if (expand_string_message == NULL)
3650           {
3651           expand_string_message =
3652             string_sprintf("Perl subroutine \"%s\" returned undef to force "
3653               "failure", sub_arg[0]);
3654           expand_string_forcedfail = TRUE;
3655           }
3656         goto EXPAND_FAILED;
3657         }
3658
3659       /* Yield succeeded. Ensure forcedfail is unset, just in case it got
3660       set during a callback from Perl. */
3661
3662       expand_string_forcedfail = FALSE;
3663       yield = new_yield;
3664       continue;
3665       }
3666     #endif /* EXIM_PERL */
3667
3668     /* Transform email address to "prvs" scheme to use
3669        as BATV-signed return path */
3670
3671     case EITEM_PRVS:
3672       {
3673       uschar *sub_arg[3];
3674       uschar *p,*domain;
3675
3676       switch(read_subs(sub_arg, 3, 2, &s, skipping, TRUE, US"prvs"))
3677         {
3678         case 1: goto EXPAND_FAILED_CURLY;
3679         case 2:
3680         case 3: goto EXPAND_FAILED;
3681         }
3682
3683       /* If skipping, we don't actually do anything */
3684       if (skipping) continue;
3685
3686       /* sub_arg[0] is the address */
3687       domain = Ustrrchr(sub_arg[0],'@');
3688       if ( (domain == NULL) || (domain == sub_arg[0]) || (Ustrlen(domain) == 1) )
3689         {
3690         expand_string_message = US"prvs first argument must be a qualified email address";
3691         goto EXPAND_FAILED;
3692         }
3693
3694       /* Calculate the hash. The second argument must be a single-digit
3695       key number, or unset. */
3696
3697       if (sub_arg[2] != NULL &&
3698           (!isdigit(sub_arg[2][0]) || sub_arg[2][1] != 0))
3699         {
3700         expand_string_message = US"prvs second argument must be a single digit";
3701         goto EXPAND_FAILED;
3702         }
3703
3704       p = prvs_hmac_sha1(sub_arg[0],sub_arg[1],sub_arg[2],prvs_daystamp(7));
3705       if (p == NULL)
3706         {
3707         expand_string_message = US"prvs hmac-sha1 conversion failed";
3708         goto EXPAND_FAILED;
3709         }
3710
3711       /* Now separate the domain from the local part */
3712       *domain++ = '\0';
3713
3714       yield = string_cat(yield,&size,&ptr,US"prvs=",5);
3715       string_cat(yield,&size,&ptr,(sub_arg[2] != NULL) ? sub_arg[2] : US"0", 1);
3716       string_cat(yield,&size,&ptr,prvs_daystamp(7),3);
3717       string_cat(yield,&size,&ptr,p,6);
3718       string_cat(yield,&size,&ptr,US"=",1);
3719       string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
3720       string_cat(yield,&size,&ptr,US"@",1);
3721       string_cat(yield,&size,&ptr,domain,Ustrlen(domain));
3722
3723       continue;
3724       }
3725
3726     /* Check a prvs-encoded address for validity */
3727
3728     case EITEM_PRVSCHECK:
3729       {
3730       uschar *sub_arg[3];
3731       int mysize = 0, myptr = 0;
3732       const pcre *re;
3733       uschar *p;
3734
3735       /* TF: Ugliness: We want to expand parameter 1 first, then set
3736          up expansion variables that are used in the expansion of
3737          parameter 2. So we clone the string for the first
3738          expansion, where we only expand parameter 1.
3739
3740          PH: Actually, that isn't necessary. The read_subs() function is
3741          designed to work this way for the ${if and ${lookup expansions. I've
3742          tidied the code.
3743       */
3744
3745       /* Reset expansion variables */
3746       prvscheck_result = NULL;
3747       prvscheck_address = NULL;
3748       prvscheck_keynum = NULL;
3749
3750       switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
3751         {
3752         case 1: goto EXPAND_FAILED_CURLY;
3753         case 2:
3754         case 3: goto EXPAND_FAILED;
3755         }
3756
3757       re = regex_must_compile(US"^prvs\\=([0-9])([0-9]{3})([A-F0-9]{6})\\=(.+)\\@(.+)$",
3758                               TRUE,FALSE);
3759
3760       if (regex_match_and_setup(re,sub_arg[0],0,-1))
3761         {
3762         uschar *local_part = string_copyn(expand_nstring[4],expand_nlength[4]);
3763         uschar *key_num = string_copyn(expand_nstring[1],expand_nlength[1]);
3764         uschar *daystamp = string_copyn(expand_nstring[2],expand_nlength[2]);
3765         uschar *hash = string_copyn(expand_nstring[3],expand_nlength[3]);
3766         uschar *domain = string_copyn(expand_nstring[5],expand_nlength[5]);
3767
3768         DEBUG(D_expand) debug_printf("prvscheck localpart: %s\n", local_part);
3769         DEBUG(D_expand) debug_printf("prvscheck key number: %s\n", key_num);
3770         DEBUG(D_expand) debug_printf("prvscheck daystamp: %s\n", daystamp);
3771         DEBUG(D_expand) debug_printf("prvscheck hash: %s\n", hash);
3772         DEBUG(D_expand) debug_printf("prvscheck domain: %s\n", domain);
3773
3774         /* Set up expansion variables */
3775         prvscheck_address = string_cat(NULL, &mysize, &myptr, local_part, Ustrlen(local_part));
3776         string_cat(prvscheck_address,&mysize,&myptr,US"@",1);
3777         string_cat(prvscheck_address,&mysize,&myptr,domain,Ustrlen(domain));
3778         prvscheck_address[myptr] = '\0';
3779         prvscheck_keynum = string_copy(key_num);
3780
3781         /* Now expand the second argument */
3782         switch(read_subs(sub_arg, 1, 1, &s, skipping, FALSE, US"prvs"))
3783           {
3784           case 1: goto EXPAND_FAILED_CURLY;
3785           case 2:
3786           case 3: goto EXPAND_FAILED;
3787           }
3788
3789         /* Now we have the key and can check the address. */
3790
3791         p = prvs_hmac_sha1(prvscheck_address, sub_arg[0], prvscheck_keynum,
3792           daystamp);
3793
3794         if (p == NULL)
3795           {
3796           expand_string_message = US"hmac-sha1 conversion failed";
3797           goto EXPAND_FAILED;
3798           }
3799
3800         DEBUG(D_expand) debug_printf("prvscheck: received hash is %s\n", hash);
3801         DEBUG(D_expand) debug_printf("prvscheck:      own hash is %s\n", p);
3802
3803         if (Ustrcmp(p,hash) == 0)
3804           {
3805           /* Success, valid BATV address. Now check the expiry date. */
3806           uschar *now = prvs_daystamp(0);
3807           unsigned int inow = 0,iexpire = 1;
3808
3809           (void)sscanf(CS now,"%u",&inow);
3810           (void)sscanf(CS daystamp,"%u",&iexpire);
3811
3812           /* When "iexpire" is < 7, a "flip" has occured.
3813              Adjust "inow" accordingly. */
3814           if ( (iexpire < 7) && (inow >= 993) ) inow = 0;
3815
3816           if (iexpire > inow)
3817             {
3818             prvscheck_result = US"1";
3819             DEBUG(D_expand) debug_printf("prvscheck: success, $pvrs_result set to 1\n");
3820             }
3821             else
3822             {
3823             prvscheck_result = NULL;
3824             DEBUG(D_expand) debug_printf("prvscheck: signature expired, $pvrs_result unset\n");
3825             }
3826           }
3827         else
3828           {
3829           prvscheck_result = NULL;
3830           DEBUG(D_expand) debug_printf("prvscheck: hash failure, $pvrs_result unset\n");
3831           }
3832
3833         /* Now expand the final argument. We leave this till now so that
3834         it can include $prvscheck_result. */
3835
3836         switch(read_subs(sub_arg, 1, 0, &s, skipping, TRUE, US"prvs"))
3837           {
3838           case 1: goto EXPAND_FAILED_CURLY;
3839           case 2:
3840           case 3: goto EXPAND_FAILED;
3841           }
3842
3843         if (sub_arg[0] == NULL || *sub_arg[0] == '\0')
3844           yield = string_cat(yield,&size,&ptr,prvscheck_address,Ustrlen(prvscheck_address));
3845         else
3846           yield = string_cat(yield,&size,&ptr,sub_arg[0],Ustrlen(sub_arg[0]));
3847
3848         /* Reset the "internal" variables afterwards, because they are in
3849         dynamic store that will be reclaimed if the expansion succeeded. */
3850
3851         prvscheck_address = NULL;
3852         prvscheck_keynum = NULL;
3853         }
3854       else
3855         {
3856         /* Does not look like a prvs encoded address, return the empty string.
3857            We need to make sure all subs are expanded first, so as to skip over
3858            the entire item. */
3859
3860         switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"prvs"))
3861           {
3862           case 1: goto EXPAND_FAILED_CURLY;
3863           case 2:
3864           case 3: goto EXPAND_FAILED;
3865           }
3866         }
3867
3868       continue;
3869       }
3870
3871     /* Handle "readfile" to insert an entire file */
3872
3873     case EITEM_READFILE:
3874       {
3875       FILE *f;
3876       uschar *sub_arg[2];
3877
3878       if ((expand_forbid & RDO_READFILE) != 0)
3879         {
3880         expand_string_message = US"file insertions are not permitted";
3881         goto EXPAND_FAILED;
3882         }
3883
3884       switch(read_subs(sub_arg, 2, 1, &s, skipping, TRUE, US"readfile"))
3885         {
3886         case 1: goto EXPAND_FAILED_CURLY;
3887         case 2:
3888         case 3: goto EXPAND_FAILED;
3889         }
3890
3891       /* If skipping, we don't actually do anything */
3892
3893       if (skipping) continue;
3894
3895       /* Open the file and read it */
3896
3897       f = Ufopen(sub_arg[0], "rb");
3898       if (f == NULL)
3899         {
3900         expand_string_message = string_open_failed(errno, "%s", sub_arg[0]);
3901         goto EXPAND_FAILED;
3902         }
3903
3904       yield = cat_file(f, yield, &size, &ptr, sub_arg[1]);
3905       (void)fclose(f);
3906       continue;
3907       }
3908
3909     /* Handle "readsocket" to insert data from a Unix domain socket */
3910
3911     case EITEM_READSOCK:
3912       {
3913       int fd;
3914       int timeout = 5;
3915       int save_ptr = ptr;
3916       FILE *f;
3917       struct sockaddr_un sockun;         /* don't call this "sun" ! */
3918       uschar *arg;
3919       uschar *sub_arg[4];
3920
3921       if ((expand_forbid & RDO_READSOCK) != 0)
3922         {
3923         expand_string_message = US"socket insertions are not permitted";
3924         goto EXPAND_FAILED;
3925         }
3926
3927       /* Read up to 4 arguments, but don't do the end of item check afterwards,
3928       because there may be a string for expansion on failure. */
3929
3930       switch(read_subs(sub_arg, 4, 2, &s, skipping, FALSE, US"readsocket"))
3931         {
3932         case 1: goto EXPAND_FAILED_CURLY;
3933         case 2:                             /* Won't occur: no end check */
3934         case 3: goto EXPAND_FAILED;
3935         }
3936
3937       /* Sort out timeout, if given */
3938
3939       if (sub_arg[2] != NULL)
3940         {
3941         timeout = readconf_readtime(sub_arg[2], 0, FALSE);
3942         if (timeout < 0)
3943           {
3944           expand_string_message = string_sprintf("bad time value %s",
3945             sub_arg[2]);
3946           goto EXPAND_FAILED;
3947           }
3948         }
3949       else sub_arg[3] = NULL;                     /* No eol if no timeout */
3950
3951       /* If skipping, we don't actually do anything. Otherwise, arrange to
3952       connect to either an IP or a Unix socket. */
3953
3954       if (!skipping)
3955         {
3956         /* Handle an IP (internet) domain */
3957
3958         if (Ustrncmp(sub_arg[0], "inet:", 5) == 0)
3959           {
3960           BOOL connected = FALSE;
3961           int namelen, port;
3962           host_item shost;
3963           host_item *h;
3964           uschar *server_name = sub_arg[0] + 5;
3965           uschar *port_name = Ustrrchr(server_name, ':');
3966
3967           /* Sort out the port */
3968
3969           if (port_name == NULL)
3970             {
3971             expand_string_message =
3972               string_sprintf("missing port for readsocket %s", sub_arg[0]);
3973             goto EXPAND_FAILED;
3974             }
3975           *port_name++ = 0;           /* Terminate server name */
3976
3977           if (isdigit(*port_name))
3978             {
3979             uschar *end;
3980             port = Ustrtol(port_name, &end, 0);
3981             if (end != port_name + Ustrlen(port_name))
3982               {
3983               expand_string_message =
3984                 string_sprintf("invalid port number %s", port_name);
3985               goto EXPAND_FAILED;
3986               }
3987             }
3988           else
3989             {
3990             struct servent *service_info = getservbyname(CS port_name, "tcp");
3991             if (service_info == NULL)
3992               {
3993               expand_string_message = string_sprintf("unknown port \"%s\"",
3994                 port_name);
3995               goto EXPAND_FAILED;
3996               }
3997             port = ntohs(service_info->s_port);
3998             }
3999
4000           /* Sort out the server. */
4001
4002           shost.next = NULL;
4003           shost.address = NULL;
4004           shost.port = port;
4005           shost.mx = -1;
4006
4007           namelen = Ustrlen(server_name);
4008
4009           /* Anything enclosed in [] must be an IP address. */
4010
4011           if (server_name[0] == '[' &&
4012               server_name[namelen - 1] == ']')
4013             {
4014             server_name[namelen - 1] = 0;
4015             server_name++;
4016             if (string_is_ip_address(server_name, NULL) == 0)
4017               {
4018               expand_string_message =
4019                 string_sprintf("malformed IP address \"%s\"", server_name);
4020               goto EXPAND_FAILED;
4021               }
4022             shost.name = shost.address = server_name;
4023             }
4024
4025           /* Otherwise check for an unadorned IP address */
4026
4027           else if (string_is_ip_address(server_name, NULL) != 0)
4028             shost.name = shost.address = server_name;
4029
4030           /* Otherwise lookup IP address(es) from the name */
4031
4032           else
4033             {
4034             shost.name = server_name;
4035             if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE, NULL,
4036                 FALSE) != HOST_FOUND)
4037               {
4038               expand_string_message =
4039                 string_sprintf("no IP address found for host %s", shost.name);
4040               goto EXPAND_FAILED;
4041               }
4042             }
4043
4044           /* Try to connect to the server - test each IP till one works */
4045
4046           for (h = &shost; h != NULL; h = h->next)
4047             {
4048             int af = (Ustrchr(h->address, ':') != 0)? AF_INET6 : AF_INET;
4049             if ((fd = ip_socket(SOCK_STREAM, af)) == -1)
4050               {
4051               expand_string_message = string_sprintf("failed to create socket: "
4052                 "%s", strerror(errno));
4053               goto SOCK_FAIL;
4054               }
4055
4056             if (ip_connect(fd, af, h->address, port, timeout) == 0)
4057               {
4058               connected = TRUE;
4059               break;
4060               }
4061             }
4062
4063           if (!connected)
4064             {
4065             expand_string_message = string_sprintf("failed to connect to "
4066               "socket %s: couldn't connect to any host", sub_arg[0],
4067               strerror(errno));
4068             goto SOCK_FAIL;
4069             }
4070           }
4071
4072         /* Handle a Unix domain socket */
4073
4074         else
4075           {
4076           int rc;
4077           if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
4078             {
4079             expand_string_message = string_sprintf("failed to create socket: %s",
4080               strerror(errno));
4081             goto SOCK_FAIL;
4082             }
4083
4084           sockun.sun_family = AF_UNIX;
4085           sprintf(sockun.sun_path, "%.*s", (int)(sizeof(sockun.sun_path)-1),
4086             sub_arg[0]);
4087
4088           sigalrm_seen = FALSE;
4089           alarm(timeout);
4090           rc = connect(fd, (struct sockaddr *)(&sockun), sizeof(sockun));
4091           alarm(0);
4092           if (sigalrm_seen)
4093             {
4094             expand_string_message = US "socket connect timed out";
4095             goto SOCK_FAIL;
4096             }
4097           if (rc < 0)
4098             {
4099             expand_string_message = string_sprintf("failed to connect to socket "
4100               "%s: %s", sub_arg[0], strerror(errno));
4101             goto SOCK_FAIL;
4102             }
4103           }
4104
4105         DEBUG(D_expand) debug_printf("connected to socket %s\n", sub_arg[0]);
4106
4107         /* Write the request string, if not empty */
4108
4109         if (sub_arg[1][0] != 0)
4110           {
4111           int len = Ustrlen(sub_arg[1]);
4112           DEBUG(D_expand) debug_printf("writing \"%s\" to socket\n",
4113             sub_arg[1]);
4114           if (write(fd, sub_arg[1], len) != len)
4115             {
4116             expand_string_message = string_sprintf("request write to socket "
4117               "failed: %s", strerror(errno));
4118             goto SOCK_FAIL;
4119             }
4120           }
4121
4122         /* Shut down the sending side of the socket. This helps some servers to
4123         recognise that it is their turn to do some work. Just in case some
4124         system doesn't have this function, make it conditional. */
4125
4126         #ifdef SHUT_WR
4127         shutdown(fd, SHUT_WR);
4128         #endif
4129
4130         /* Now we need to read from the socket, under a timeout. The function
4131         that reads a file can be used. */
4132
4133         f = fdopen(fd, "rb");
4134         sigalrm_seen = FALSE;
4135         alarm(timeout);
4136         yield = cat_file(f, yield, &size, &ptr, sub_arg[3]);
4137         alarm(0);
4138         (void)fclose(f);
4139
4140         /* After a timeout, we restore the pointer in the result, that is,
4141         make sure we add nothing from the socket. */
4142
4143         if (sigalrm_seen)
4144           {
4145           ptr = save_ptr;
4146           expand_string_message = US "socket read timed out";
4147           goto SOCK_FAIL;
4148           }
4149         }
4150
4151       /* The whole thing has worked (or we were skipping). If there is a
4152       failure string following, we need to skip it. */
4153
4154       if (*s == '{')
4155         {
4156         if (expand_string_internal(s+1, TRUE, &s, TRUE) == NULL)
4157           goto EXPAND_FAILED;
4158         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4159         while (isspace(*s)) s++;
4160         }
4161       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4162       continue;
4163
4164       /* Come here on failure to create socket, connect socket, write to the
4165       socket, or timeout on reading. If another substring follows, expand and
4166       use it. Otherwise, those conditions give expand errors. */
4167
4168       SOCK_FAIL:
4169       if (*s != '{') goto EXPAND_FAILED;
4170       DEBUG(D_any) debug_printf("%s\n", expand_string_message);
4171       arg = expand_string_internal(s+1, TRUE, &s, FALSE);
4172       if (arg == NULL) goto EXPAND_FAILED;
4173       yield = string_cat(yield, &size, &ptr, arg, Ustrlen(arg));
4174       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4175       while (isspace(*s)) s++;
4176       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4177       continue;
4178       }
4179
4180     /* Handle "run" to execute a program. */
4181
4182     case EITEM_RUN:
4183       {
4184       FILE *f;
4185       uschar *arg;
4186       uschar **argv;
4187       pid_t pid;
4188       int fd_in, fd_out;
4189       int lsize = 0;
4190       int lptr = 0;
4191
4192       if ((expand_forbid & RDO_RUN) != 0)
4193         {
4194         expand_string_message = US"running a command is not permitted";
4195         goto EXPAND_FAILED;
4196         }
4197
4198       while (isspace(*s)) s++;
4199       if (*s != '{') goto EXPAND_FAILED_CURLY;
4200       arg = expand_string_internal(s+1, TRUE, &s, skipping);
4201       if (arg == NULL) goto EXPAND_FAILED;
4202       while (isspace(*s)) s++;
4203       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4204
4205       if (skipping)   /* Just pretend it worked when we're skipping */
4206         {
4207         runrc = 0;
4208         }
4209       else
4210         {
4211         if (!transport_set_up_command(&argv,    /* anchor for arg list */
4212             arg,                                /* raw command */
4213             FALSE,                              /* don't expand the arguments */
4214             0,                                  /* not relevant when... */
4215             NULL,                               /* no transporting address */
4216             US"${run} expansion",               /* for error messages */
4217             &expand_string_message))            /* where to put error message */
4218           {
4219           goto EXPAND_FAILED;
4220           }
4221
4222         /* Create the child process, making it a group leader. */
4223
4224         pid = child_open(argv, NULL, 0077, &fd_in, &fd_out, TRUE);
4225
4226         if (pid < 0)
4227           {
4228           expand_string_message =
4229             string_sprintf("couldn't create child process: %s", strerror(errno));
4230           goto EXPAND_FAILED;
4231           }
4232
4233         /* Nothing is written to the standard input. */
4234
4235         (void)close(fd_in);
4236
4237         /* Wait for the process to finish, applying the timeout, and inspect its
4238         return code for serious disasters. Simple non-zero returns are passed on.
4239         */
4240
4241         if ((runrc = child_close(pid, 60)) < 0)
4242           {
4243           if (runrc == -256)
4244             {
4245             expand_string_message = string_sprintf("command timed out");
4246             killpg(pid, SIGKILL);       /* Kill the whole process group */
4247             }
4248
4249           else if (runrc == -257)
4250             expand_string_message = string_sprintf("wait() failed: %s",
4251               strerror(errno));
4252
4253           else
4254             expand_string_message = string_sprintf("command killed by signal %d",
4255               -runrc);
4256
4257           goto EXPAND_FAILED;
4258           }
4259
4260         /* Read the pipe to get the command's output into $value (which is kept
4261         in lookup_value). */
4262
4263         f = fdopen(fd_out, "rb");
4264         lookup_value = NULL;
4265         lookup_value = cat_file(f, lookup_value, &lsize, &lptr, NULL);
4266         (void)fclose(f);
4267         }
4268
4269       /* Process the yes/no strings; $value may be useful in both cases */
4270
4271       switch(process_yesno(
4272                skipping,                     /* were previously skipping */
4273                runrc == 0,                   /* success/failure indicator */
4274                lookup_value,                 /* value to reset for string2 */
4275                &s,                           /* input pointer */
4276                &yield,                       /* output pointer */
4277                &size,                        /* output size */
4278                &ptr,                         /* output current point */
4279                US"run"))                     /* condition type */
4280         {
4281         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4282         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4283         }
4284
4285       continue;
4286       }
4287
4288     /* Handle character translation for "tr" */
4289
4290     case EITEM_TR:
4291       {
4292       int oldptr = ptr;
4293       int o2m;
4294       uschar *sub[3];
4295
4296       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"tr"))
4297         {
4298         case 1: goto EXPAND_FAILED_CURLY;
4299         case 2:
4300         case 3: goto EXPAND_FAILED;
4301         }
4302
4303       yield = string_cat(yield, &size, &ptr, sub[0], Ustrlen(sub[0]));
4304       o2m = Ustrlen(sub[2]) - 1;
4305
4306       if (o2m >= 0) for (; oldptr < ptr; oldptr++)
4307         {
4308         uschar *m = Ustrrchr(sub[1], yield[oldptr]);
4309         if (m != NULL)
4310           {
4311           int o = m - sub[1];
4312           yield[oldptr] = sub[2][(o < o2m)? o : o2m];
4313           }
4314         }
4315
4316       continue;
4317       }
4318
4319     /* Handle "hash", "length", "nhash", and "substr" when they are given with
4320     expanded arguments. */
4321
4322     case EITEM_HASH:
4323     case EITEM_LENGTH:
4324     case EITEM_NHASH:
4325     case EITEM_SUBSTR:
4326       {
4327       int i;
4328       int len;
4329       uschar *ret;
4330       int val[2] = { 0, -1 };
4331       uschar *sub[3];
4332
4333       /* "length" takes only 2 arguments whereas the others take 2 or 3.
4334       Ensure that sub[2] is set in the ${length case. */
4335
4336       sub[2] = NULL;
4337       switch(read_subs(sub, (item_type == EITEM_LENGTH)? 2:3, 2, &s, skipping,
4338              TRUE, name))
4339         {
4340         case 1: goto EXPAND_FAILED_CURLY;
4341         case 2:
4342         case 3: goto EXPAND_FAILED;
4343         }
4344
4345       /* Juggle the arguments if there are only two of them: always move the
4346       string to the last position and make ${length{n}{str}} equivalent to
4347       ${substr{0}{n}{str}}. See the defaults for val[] above. */
4348
4349       if (sub[2] == NULL)
4350         {
4351         sub[2] = sub[1];
4352         sub[1] = NULL;
4353         if (item_type == EITEM_LENGTH)
4354           {
4355           sub[1] = sub[0];
4356           sub[0] = NULL;
4357           }
4358         }
4359
4360       for (i = 0; i < 2; i++)
4361         {
4362         if (sub[i] == NULL) continue;
4363         val[i] = (int)Ustrtol(sub[i], &ret, 10);
4364         if (*ret != 0 || (i != 0 && val[i] < 0))
4365           {
4366           expand_string_message = string_sprintf("\"%s\" is not a%s number "
4367             "(in \"%s\" expansion)", sub[i], (i != 0)? " positive" : "", name);
4368           goto EXPAND_FAILED;
4369           }
4370         }
4371
4372       ret =
4373         (item_type == EITEM_HASH)?
4374           compute_hash(sub[2], val[0], val[1], &len) :
4375         (item_type == EITEM_NHASH)?
4376           compute_nhash(sub[2], val[0], val[1], &len) :
4377           extract_substr(sub[2], val[0], val[1], &len);
4378
4379       if (ret == NULL) goto EXPAND_FAILED;
4380       yield = string_cat(yield, &size, &ptr, ret, len);
4381       continue;
4382       }
4383
4384     /* Handle HMAC computation: ${hmac{<algorithm>}{<secret>}{<text>}}
4385     This code originally contributed by Steve Haslam. It currently supports
4386     the use of MD5 and SHA-1 hashes.
4387
4388     We need some workspace that is large enough to handle all the supported
4389     hash types. Use macros to set the sizes rather than be too elaborate. */
4390
4391     #define MAX_HASHLEN      20
4392     #define MAX_HASHBLOCKLEN 64
4393
4394     case EITEM_HMAC:
4395       {
4396       uschar *sub[3];
4397       md5 md5_base;
4398       sha1 sha1_base;
4399       void *use_base;
4400       int type, i;
4401       int hashlen;      /* Number of octets for the hash algorithm's output */
4402       int hashblocklen; /* Number of octets the hash algorithm processes */
4403       uschar *keyptr, *p;
4404       unsigned int keylen;
4405
4406       uschar keyhash[MAX_HASHLEN];
4407       uschar innerhash[MAX_HASHLEN];
4408       uschar finalhash[MAX_HASHLEN];
4409       uschar finalhash_hex[2*MAX_HASHLEN];
4410       uschar innerkey[MAX_HASHBLOCKLEN];
4411       uschar outerkey[MAX_HASHBLOCKLEN];
4412
4413       switch (read_subs(sub, 3, 3, &s, skipping, TRUE, name))
4414         {
4415         case 1: goto EXPAND_FAILED_CURLY;
4416         case 2:
4417         case 3: goto EXPAND_FAILED;
4418         }
4419
4420       if (Ustrcmp(sub[0], "md5") == 0)
4421         {
4422         type = HMAC_MD5;
4423         use_base = &md5_base;
4424         hashlen = 16;
4425         hashblocklen = 64;
4426         }
4427       else if (Ustrcmp(sub[0], "sha1") == 0)
4428         {
4429         type = HMAC_SHA1;
4430         use_base = &sha1_base;
4431         hashlen = 20;
4432         hashblocklen = 64;
4433         }
4434       else
4435         {
4436         expand_string_message =
4437           string_sprintf("hmac algorithm \"%s\" is not recognised", sub[0]);
4438         goto EXPAND_FAILED;
4439         }
4440
4441       keyptr = sub[1];
4442       keylen = Ustrlen(keyptr);
4443
4444       /* If the key is longer than the hash block length, then hash the key
4445       first */
4446
4447       if (keylen > hashblocklen)
4448         {
4449         chash_start(type, use_base);
4450         chash_end(type, use_base, keyptr, keylen, keyhash);
4451         keyptr = keyhash;
4452         keylen = hashlen;
4453         }
4454
4455       /* Now make the inner and outer key values */
4456
4457       memset(innerkey, 0x36, hashblocklen);
4458       memset(outerkey, 0x5c, hashblocklen);
4459
4460       for (i = 0; i < keylen; i++)
4461         {
4462         innerkey[i] ^= keyptr[i];
4463         outerkey[i] ^= keyptr[i];
4464         }
4465
4466       /* Now do the hashes */
4467
4468       chash_start(type, use_base);
4469       chash_mid(type, use_base, innerkey);
4470       chash_end(type, use_base, sub[2], Ustrlen(sub[2]), innerhash);
4471
4472       chash_start(type, use_base);
4473       chash_mid(type, use_base, outerkey);
4474       chash_end(type, use_base, innerhash, hashlen, finalhash);
4475
4476       /* Encode the final hash as a hex string */
4477
4478       p = finalhash_hex;
4479       for (i = 0; i < hashlen; i++)
4480         {
4481         *p++ = hex_digits[(finalhash[i] & 0xf0) >> 4];
4482         *p++ = hex_digits[finalhash[i] & 0x0f];
4483         }
4484
4485       DEBUG(D_any) debug_printf("HMAC[%s](%.*s,%.*s)=%.*s\n", sub[0],
4486         (int)keylen, keyptr, Ustrlen(sub[2]), sub[2], hashlen*2, finalhash_hex);
4487
4488       yield = string_cat(yield, &size, &ptr, finalhash_hex, hashlen*2);
4489       }
4490
4491     continue;
4492
4493     /* Handle global substitution for "sg" - like Perl's s/xxx/yyy/g operator.
4494     We have to save the numerical variables and restore them afterwards. */
4495
4496     case EITEM_SG:
4497       {
4498       const pcre *re;
4499       int moffset, moffsetextra, slen;
4500       int roffset;
4501       int emptyopt;
4502       const uschar *rerror;
4503       uschar *subject;
4504       uschar *sub[3];
4505       int save_expand_nmax =
4506         save_expand_strings(save_expand_nstring, save_expand_nlength);
4507
4508       switch(read_subs(sub, 3, 3, &s, skipping, TRUE, US"sg"))
4509         {
4510         case 1: goto EXPAND_FAILED_CURLY;
4511         case 2:
4512         case 3: goto EXPAND_FAILED;
4513         }
4514
4515       /* Compile the regular expression */
4516
4517       re = pcre_compile(CS sub[1], PCRE_COPT, (const char **)&rerror, &roffset,
4518         NULL);
4519
4520       if (re == NULL)
4521         {
4522         expand_string_message = string_sprintf("regular expression error in "
4523           "\"%s\": %s at offset %d", sub[1], rerror, roffset);
4524         goto EXPAND_FAILED;
4525         }
4526
4527       /* Now run a loop to do the substitutions as often as necessary. It ends
4528       when there are no more matches. Take care over matches of the null string;
4529       do the same thing as Perl does. */
4530
4531       subject = sub[0];
4532       slen = Ustrlen(sub[0]);
4533       moffset = moffsetextra = 0;
4534       emptyopt = 0;
4535
4536       for (;;)
4537         {
4538         int ovector[3*(EXPAND_MAXN+1)];
4539         int n = pcre_exec(re, NULL, CS subject, slen, moffset + moffsetextra,
4540           PCRE_EOPT | emptyopt, ovector, sizeof(ovector)/sizeof(int));
4541         int nn;
4542         uschar *insert;
4543
4544         /* No match - if we previously set PCRE_NOTEMPTY after a null match, this
4545         is not necessarily the end. We want to repeat the match from one
4546         character further along, but leaving the basic offset the same (for
4547         copying below). We can't be at the end of the string - that was checked
4548         before setting PCRE_NOTEMPTY. If PCRE_NOTEMPTY is not set, we are
4549         finished; copy the remaining string and end the loop. */
4550
4551         if (n < 0)
4552           {
4553           if (emptyopt != 0)
4554             {
4555             moffsetextra = 1;
4556             emptyopt = 0;
4557             continue;
4558             }
4559           yield = string_cat(yield, &size, &ptr, subject+moffset, slen-moffset);
4560           break;
4561           }
4562
4563         /* Match - set up for expanding the replacement. */
4564
4565         if (n == 0) n = EXPAND_MAXN + 1;
4566         expand_nmax = 0;
4567         for (nn = 0; nn < n*2; nn += 2)
4568           {
4569           expand_nstring[expand_nmax] = subject + ovector[nn];
4570           expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
4571           }
4572         expand_nmax--;
4573
4574         /* Copy the characters before the match, plus the expanded insertion. */
4575
4576         yield = string_cat(yield, &size, &ptr, subject + moffset,
4577           ovector[0] - moffset);
4578         insert = expand_string(sub[2]);
4579         if (insert == NULL) goto EXPAND_FAILED;
4580         yield = string_cat(yield, &size, &ptr, insert, Ustrlen(insert));
4581
4582         moffset = ovector[1];
4583         moffsetextra = 0;
4584         emptyopt = 0;
4585
4586         /* If we have matched an empty string, first check to see if we are at
4587         the end of the subject. If so, the loop is over. Otherwise, mimic
4588         what Perl's /g options does. This turns out to be rather cunning. First
4589         we set PCRE_NOTEMPTY and PCRE_ANCHORED and try the match a non-empty
4590         string at the same point. If this fails (picked up above) we advance to
4591         the next character. */
4592
4593         if (ovector[0] == ovector[1])
4594           {
4595           if (ovector[0] == slen) break;
4596           emptyopt = PCRE_NOTEMPTY | PCRE_ANCHORED;
4597           }
4598         }
4599
4600       /* All done - restore numerical variables. */
4601
4602       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4603         save_expand_nlength);
4604       continue;
4605       }
4606
4607     /* Handle keyed and numbered substring extraction. If the first argument
4608     consists entirely of digits, then a numerical extraction is assumed. */
4609
4610     case EITEM_EXTRACT:
4611       {
4612       int i;
4613       int j = 2;
4614       int field_number = 1;
4615       BOOL field_number_set = FALSE;
4616       uschar *save_lookup_value = lookup_value;
4617       uschar *sub[3];
4618       int save_expand_nmax =
4619         save_expand_strings(save_expand_nstring, save_expand_nlength);
4620
4621       /* Read the arguments */
4622
4623       for (i = 0; i < j; i++)
4624         {
4625         while (isspace(*s)) s++;
4626         if (*s == '{')
4627           {
4628           sub[i] = expand_string_internal(s+1, TRUE, &s, skipping);
4629           if (sub[i] == NULL) goto EXPAND_FAILED;
4630           if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4631
4632           /* After removal of leading and trailing white space, the first
4633           argument must not be empty; if it consists entirely of digits
4634           (optionally preceded by a minus sign), this is a numerical
4635           extraction, and we expect 3 arguments. */
4636
4637           if (i == 0)
4638             {
4639             int len;
4640             int x = 0;
4641             uschar *p = sub[0];
4642
4643             while (isspace(*p)) p++;
4644             sub[0] = p;
4645
4646             len = Ustrlen(p);
4647             while (len > 0 && isspace(p[len-1])) len--;
4648             p[len] = 0;
4649
4650             if (*p == 0)
4651               {
4652               expand_string_message = US"first argument of \"extract\" must "
4653                 "not be empty";
4654               goto EXPAND_FAILED;
4655               }
4656
4657             if (*p == '-')
4658               {
4659               field_number = -1;
4660               p++;
4661               }
4662             while (*p != 0 && isdigit(*p)) x = x * 10 + *p++ - '0';
4663             if (*p == 0)
4664               {
4665               field_number *= x;
4666               j = 3;               /* Need 3 args */
4667               field_number_set = TRUE;
4668               }
4669             }
4670           }
4671         else goto EXPAND_FAILED_CURLY;
4672         }
4673
4674       /* Extract either the numbered or the keyed substring into $value. If
4675       skipping, just pretend the extraction failed. */
4676
4677       lookup_value = skipping? NULL : field_number_set?
4678         expand_gettokened(field_number, sub[1], sub[2]) :
4679         expand_getkeyed(sub[0], sub[1]);
4680
4681       /* If no string follows, $value gets substituted; otherwise there can
4682       be yes/no strings, as for lookup or if. */
4683
4684       switch(process_yesno(
4685                skipping,                     /* were previously skipping */
4686                lookup_value != NULL,         /* success/failure indicator */
4687                save_lookup_value,            /* value to reset for string2 */
4688                &s,                           /* input pointer */
4689                &yield,                       /* output pointer */
4690                &size,                        /* output size */
4691                &ptr,                         /* output current point */
4692                US"extract"))                 /* condition type */
4693         {
4694         case 1: goto EXPAND_FAILED;          /* when all is well, the */
4695         case 2: goto EXPAND_FAILED_CURLY;    /* returned value is 0 */
4696         }
4697
4698       /* All done - restore numerical variables. */
4699
4700       restore_expand_strings(save_expand_nmax, save_expand_nstring,
4701         save_expand_nlength);
4702
4703       continue;
4704       }
4705
4706
4707     /* Handle list operations */
4708
4709     case EITEM_FILTER:
4710     case EITEM_MAP:
4711     case EITEM_REDUCE:
4712       {
4713       int sep = 0;
4714       int save_ptr = ptr;
4715       uschar outsep[2] = { '\0', '\0' };
4716       uschar *list, *expr, *temp;
4717       uschar *save_iterate_item = iterate_item;
4718       uschar *save_lookup_value = lookup_value;
4719
4720       while (isspace(*s)) s++;
4721       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4722
4723       list = expand_string_internal(s, TRUE, &s, skipping);
4724       if (list == NULL) goto EXPAND_FAILED;
4725       if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4726
4727       if (item_type == EITEM_REDUCE)
4728         {
4729         while (isspace(*s)) s++;
4730         if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4731         temp = expand_string_internal(s, TRUE, &s, skipping);
4732         if (temp == NULL) goto EXPAND_FAILED;
4733         lookup_value = temp;
4734         if (*s++ != '}') goto EXPAND_FAILED_CURLY;
4735         }
4736
4737       while (isspace(*s)) s++;
4738       if (*s++ != '{') goto EXPAND_FAILED_CURLY;
4739
4740       expr = s;
4741
4742       /* For EITEM_FILTER, call eval_condition once, with result discarded (as
4743       if scanning a "false" part). This allows us to find the end of the
4744       condition, because if the list is empty, we won't actually evaluate the
4745       condition for real. For EITEM_MAP and EITEM_REDUCE, do the same, using
4746       the normal internal expansion function. */
4747
4748       if (item_type == EITEM_FILTER)
4749         {
4750         temp = eval_condition(expr, NULL);
4751         if (temp != NULL) s = temp;
4752         }
4753       else
4754         {
4755         temp = expand_string_internal(s, TRUE, &s, TRUE);
4756         }
4757
4758       if (temp == NULL)
4759         {
4760         expand_string_message = string_sprintf("%s inside \"%s\" item",
4761           expand_string_message, name);
4762         goto EXPAND_FAILED;
4763         }
4764
4765       while (isspace(*s)) s++;
4766       if (*s++ != '}')
4767         {
4768         expand_string_message = string_sprintf("missing } at end of condition "
4769           "or expression inside \"%s\"", name);
4770         goto EXPAND_FAILED;
4771         }
4772
4773       while (isspace(*s)) s++;
4774       if (*s++ != '}')
4775         {
4776         expand_string_message = string_sprintf("missing } at end of \"%s\"",
4777           name);
4778         goto EXPAND_FAILED;
4779         }
4780
4781       /* If we are skipping, we can now just move on to the next item. When
4782       processing for real, we perform the iteration. */
4783
4784       if (skipping) continue;
4785       while ((iterate_item = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
4786         {
4787         *outsep = (uschar)sep;      /* Separator as a string */
4788
4789         DEBUG(D_expand) debug_printf("%s: $item = \"%s\"\n", name, iterate_item);
4790
4791         if (item_type == EITEM_FILTER)
4792           {
4793           BOOL condresult;
4794           if (eval_condition(expr, &condresult) == NULL)
4795             {
4796             iterate_item = save_iterate_item;
4797             lookup_value = save_lookup_value;
4798             expand_string_message = string_sprintf("%s inside \"%s\" condition",
4799               expand_string_message, name);
4800             goto EXPAND_FAILED;
4801             }
4802           DEBUG(D_expand) debug_printf("%s: condition is %s\n", name,
4803             condresult? "true":"false");
4804           if (condresult)
4805             temp = iterate_item;    /* TRUE => include this item */
4806           else
4807             continue;               /* FALSE => skip this item */
4808           }
4809
4810         /* EITEM_MAP and EITEM_REDUCE */
4811
4812         else
4813           {
4814           temp = expand_string_internal(expr, TRUE, NULL, skipping);
4815           if (temp == NULL)
4816             {
4817             iterate_item = save_iterate_item;
4818             expand_string_message = string_sprintf("%s inside \"%s\" item",
4819               expand_string_message, name);
4820             goto EXPAND_FAILED;
4821             }
4822           if (item_type == EITEM_REDUCE)
4823             {
4824             lookup_value = temp;      /* Update the value of $value */
4825             continue;                 /* and continue the iteration */
4826             }
4827           }
4828
4829         /* We reach here for FILTER if the condition is true, always for MAP,
4830         and never for REDUCE. The value in "temp" is to be added to the output
4831         list that is being created, ensuring that any occurrences of the
4832         separator character are doubled. Unless we are dealing with the first
4833         item of the output list, add in a space if the new item begins with the
4834         separator character, or is an empty string. */
4835
4836         if (ptr != save_ptr && (temp[0] == *outsep || temp[0] == 0))
4837           yield = string_cat(yield, &size, &ptr, US" ", 1);
4838
4839         /* Add the string in "temp" to the output list that we are building,
4840         This is done in chunks by searching for the separator character. */
4841
4842         for (;;)
4843           {
4844           size_t seglen = Ustrcspn(temp, outsep);
4845             yield = string_cat(yield, &size, &ptr, temp, seglen + 1);
4846
4847           /* If we got to the end of the string we output one character
4848           too many; backup and end the loop. Otherwise arrange to double the
4849           separator. */
4850
4851           if (temp[seglen] == '\0') { ptr--; break; }
4852           yield = string_cat(yield, &size, &ptr, outsep, 1);
4853           temp += seglen + 1;
4854           }
4855
4856         /* Output a separator after the string: we will remove the redundant
4857         final one at the end. */
4858
4859         yield = string_cat(yield, &size, &ptr, outsep, 1);
4860         }   /* End of iteration over the list loop */
4861
4862       /* REDUCE has generated no output above: output the final value of
4863       $value. */
4864
4865       if (item_type == EITEM_REDUCE)
4866         {
4867         yield = string_cat(yield, &size, &ptr, lookup_value,
4868           Ustrlen(lookup_value));
4869         lookup_value = save_lookup_value;  /* Restore $value */
4870         }
4871
4872       /* FILTER and MAP generate lists: if they have generated anything, remove
4873       the redundant final separator. Even though an empty item at the end of a
4874       list does not count, this is tidier. */
4875
4876       else if (ptr != save_ptr) ptr--;
4877
4878       /* Restore preserved $item */
4879
4880       iterate_item = save_iterate_item;
4881       continue;
4882       }
4883
4884
4885     /* If ${dlfunc support is configured, handle calling dynamically-loaded
4886     functions, unless locked out at this time. Syntax is ${dlfunc{file}{func}}
4887     or ${dlfunc{file}{func}{arg}} or ${dlfunc{file}{func}{arg1}{arg2}} or up to
4888     a maximum of EXPAND_DLFUNC_MAX_ARGS arguments (defined below). */
4889
4890     #define EXPAND_DLFUNC_MAX_ARGS 8
4891
4892     case EITEM_DLFUNC:
4893     #ifndef EXPAND_DLFUNC
4894     expand_string_message = US"\"${dlfunc\" encountered, but this facility "
4895       "is not included in this binary";
4896     goto EXPAND_FAILED;
4897
4898     #else   /* EXPAND_DLFUNC */
4899       {
4900       tree_node *t;
4901       exim_dlfunc_t *func;
4902       uschar *result;
4903       int status, argc;
4904       uschar *argv[EXPAND_DLFUNC_MAX_ARGS + 3];
4905
4906       if ((expand_forbid & RDO_DLFUNC) != 0)
4907         {
4908         expand_string_message =
4909           US"dynamically-loaded functions are not permitted";
4910         goto EXPAND_FAILED;
4911         }
4912
4913       switch(read_subs(argv, EXPAND_DLFUNC_MAX_ARGS + 2, 2, &s, skipping,
4914            TRUE, US"dlfunc"))
4915         {
4916         case 1: goto EXPAND_FAILED_CURLY;
4917         case 2:
4918         case 3: goto EXPAND_FAILED;
4919         }
4920
4921       /* If skipping, we don't actually do anything */
4922
4923       if (skipping) continue;
4924
4925       /* Look up the dynamically loaded object handle in the tree. If it isn't
4926       found, dlopen() the file and put the handle in the tree for next time. */
4927
4928       t = tree_search(dlobj_anchor, argv[0]);
4929       if (t == NULL)
4930         {
4931         void *handle = dlopen(CS argv[0], RTLD_LAZY);
4932         if (handle == NULL)
4933           {
4934           expand_string_message = string_sprintf("dlopen \"%s\" failed: %s",
4935             argv[0], dlerror());
4936           log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
4937           goto EXPAND_FAILED;
4938           }
4939         t = store_get_perm(sizeof(tree_node) + Ustrlen(argv[0]));
4940         Ustrcpy(t->name, argv[0]);
4941         t->data.ptr = handle;
4942         (void)tree_insertnode(&dlobj_anchor, t);
4943         }
4944
4945       /* Having obtained the dynamically loaded object handle, look up the
4946       function pointer. */
4947
4948       func = (exim_dlfunc_t *)dlsym(t->data.ptr, CS argv[1]);
4949       if (func == NULL)
4950         {
4951         expand_string_message = string_sprintf("dlsym \"%s\" in \"%s\" failed: "
4952           "%s", argv[1], argv[0], dlerror());
4953         log_write(0, LOG_MAIN|LOG_PANIC, "%s", expand_string_message);
4954         goto EXPAND_FAILED;
4955         }
4956
4957       /* Call the function and work out what to do with the result. If it
4958       returns OK, we have a replacement string; if it returns DEFER then
4959       expansion has failed in a non-forced manner; if it returns FAIL then
4960       failure was forced; if it returns ERROR or any other value there's a
4961       problem, so panic slightly. */
4962
4963       result = NULL;
4964       for (argc = 0; argv[argc] != NULL; argc++);
4965       status = func(&result, argc - 2, &argv[2]);
4966       if(status == OK)
4967         {
4968         if (result == NULL) result = US"";
4969         yield = string_cat(yield, &size, &ptr, result, Ustrlen(result));
4970         continue;
4971         }
4972       else
4973         {
4974         expand_string_message = result == NULL ? US"(no message)" : result;
4975         if(status == FAIL_FORCED) expand_string_forcedfail = TRUE;
4976           else if(status != FAIL)
4977             log_write(0, LOG_MAIN|LOG_PANIC, "dlfunc{%s}{%s} failed (%d): %s",
4978               argv[0], argv[1], status, expand_string_message);
4979         goto EXPAND_FAILED;
4980         }
4981       }
4982     #endif /* EXPAND_DLFUNC */
4983     }
4984
4985   /* Control reaches here if the name is not recognized as one of the more
4986   complicated expansion items. Check for the "operator" syntax (name terminated
4987   by a colon). Some of the operators have arguments, separated by _ from the
4988   name. */
4989
4990   if (*s == ':')
4991     {
4992     int c;
4993     uschar *arg = NULL;
4994     uschar *sub = expand_string_internal(s+1, TRUE, &s, skipping);
4995     if (sub == NULL) goto EXPAND_FAILED;
4996     s++;
4997
4998     /* Owing to an historical mis-design, an underscore may be part of the
4999     operator name, or it may introduce arguments.  We therefore first scan the
5000     table of names that contain underscores. If there is no match, we cut off
5001     the arguments and then scan the main table. */
5002
5003     c = chop_match(name, op_table_underscore,
5004       sizeof(op_table_underscore)/sizeof(uschar *));
5005
5006     if (c < 0)
5007       {
5008       arg = Ustrchr(name, '_');
5009       if (arg != NULL) *arg = 0;
5010       c = chop_match(name, op_table_main,
5011         sizeof(op_table_main)/sizeof(uschar *));
5012       if (c >= 0) c += sizeof(op_table_underscore)/sizeof(uschar *);
5013       if (arg != NULL) *arg++ = '_';   /* Put back for error messages */
5014       }
5015
5016     /* If we are skipping, we don't need to perform the operation at all.
5017     This matters for operations like "mask", because the data may not be
5018     in the correct format when skipping. For example, the expression may test
5019     for the existence of $sender_host_address before trying to mask it. For
5020     other operations, doing them may not fail, but it is a waste of time. */
5021
5022     if (skipping && c >= 0) continue;
5023
5024     /* Otherwise, switch on the operator type */
5025
5026     switch(c)
5027       {
5028       case EOP_BASE62:
5029         {
5030         uschar *t;
5031         unsigned long int n = Ustrtoul(sub, &t, 10);
5032         if (*t != 0)
5033           {
5034           expand_string_message = string_sprintf("argument for base62 "
5035             "operator is \"%s\", which is not a decimal number", sub);
5036           goto EXPAND_FAILED;
5037           }
5038         t = string_base62(n);
5039         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5040         continue;
5041         }
5042
5043       /* Note that for Darwin and Cygwin, BASE_62 actually has the value 36 */
5044
5045       case EOP_BASE62D:
5046         {
5047         uschar buf[16];
5048         uschar *tt = sub;
5049         unsigned long int n = 0;
5050         while (*tt != 0)
5051           {
5052           uschar *t = Ustrchr(base62_chars, *tt++);
5053           if (t == NULL)
5054             {
5055             expand_string_message = string_sprintf("argument for base62d "
5056               "operator is \"%s\", which is not a base %d number", sub,
5057               BASE_62);
5058             goto EXPAND_FAILED;
5059             }
5060           n = n * BASE_62 + (t - base62_chars);
5061           }
5062         (void)sprintf(CS buf, "%ld", n);
5063         yield = string_cat(yield, &size, &ptr, buf, Ustrlen(buf));
5064         continue;
5065         }
5066
5067       case EOP_EXPAND:
5068         {
5069         uschar *expanded = expand_string_internal(sub, FALSE, NULL, skipping);
5070         if (expanded == NULL)
5071           {
5072           expand_string_message =
5073             string_sprintf("internal expansion of \"%s\" failed: %s", sub,
5074               expand_string_message);
5075           goto EXPAND_FAILED;
5076           }
5077         yield = string_cat(yield, &size, &ptr, expanded, Ustrlen(expanded));
5078         continue;
5079         }
5080
5081       case EOP_LC:
5082         {
5083         int count = 0;
5084         uschar *t = sub - 1;
5085         while (*(++t) != 0) { *t = tolower(*t); count++; }
5086         yield = string_cat(yield, &size, &ptr, sub, count);
5087         continue;
5088         }
5089
5090       case EOP_UC:
5091         {
5092         int count = 0;
5093         uschar *t = sub - 1;
5094         while (*(++t) != 0) { *t = toupper(*t); count++; }
5095         yield = string_cat(yield, &size, &ptr, sub, count);
5096         continue;
5097         }
5098
5099       case EOP_MD5:
5100         {
5101         md5 base;
5102         uschar digest[16];
5103         int j;
5104         char st[33];
5105         md5_start(&base);
5106         md5_end(&base, sub, Ustrlen(sub), digest);
5107         for(j = 0; j < 16; j++) sprintf(st+2*j, "%02x", digest[j]);
5108         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5109         continue;
5110         }
5111
5112       case EOP_SHA1:
5113         {
5114         sha1 base;
5115         uschar digest[20];
5116         int j;
5117         char st[41];
5118         sha1_start(&base);
5119         sha1_end(&base, sub, Ustrlen(sub), digest);
5120         for(j = 0; j < 20; j++) sprintf(st+2*j, "%02X", digest[j]);
5121         yield = string_cat(yield, &size, &ptr, US st, (int)strlen(st));
5122         continue;
5123         }
5124
5125       /* Convert hex encoding to base64 encoding */
5126
5127       case EOP_HEX2B64:
5128         {
5129         int c = 0;
5130         int b = -1;
5131         uschar *in = sub;
5132         uschar *out = sub;
5133         uschar *enc;
5134
5135         for (enc = sub; *enc != 0; enc++)
5136           {
5137           if (!isxdigit(*enc))
5138             {
5139             expand_string_message = string_sprintf("\"%s\" is not a hex "
5140               "string", sub);
5141             goto EXPAND_FAILED;
5142             }
5143           c++;
5144           }
5145
5146         if ((c & 1) != 0)
5147           {
5148           expand_string_message = string_sprintf("\"%s\" contains an odd "
5149             "number of characters", sub);
5150           goto EXPAND_FAILED;
5151           }
5152
5153         while ((c = *in++) != 0)
5154           {
5155           if (isdigit(c)) c -= '0';
5156           else c = toupper(c) - 'A' + 10;
5157           if (b == -1)
5158             {
5159             b = c << 4;
5160             }
5161           else
5162             {
5163             *out++ = b | c;
5164             b = -1;
5165             }
5166           }
5167
5168         enc = auth_b64encode(sub, out - sub);
5169         yield = string_cat(yield, &size, &ptr, enc, Ustrlen(enc));
5170         continue;
5171         }
5172
5173       /* mask applies a mask to an IP address; for example the result of
5174       ${mask:131.111.10.206/28} is 131.111.10.192/28. */
5175
5176       case EOP_MASK:
5177         {
5178         int count;
5179         uschar *endptr;
5180         int binary[4];
5181         int mask, maskoffset;
5182         int type = string_is_ip_address(sub, &maskoffset);
5183         uschar buffer[64];
5184
5185         if (type == 0)
5186           {
5187           expand_string_message = string_sprintf("\"%s\" is not an IP address",
5188            sub);
5189           goto EXPAND_FAILED;
5190           }
5191
5192         if (maskoffset == 0)
5193           {
5194           expand_string_message = string_sprintf("missing mask value in \"%s\"",
5195             sub);
5196           goto EXPAND_FAILED;
5197           }
5198
5199         mask = Ustrtol(sub + maskoffset + 1, &endptr, 10);
5200
5201         if (*endptr != 0 || mask < 0 || mask > ((type == 4)? 32 : 128))
5202           {
5203           expand_string_message = string_sprintf("mask value too big in \"%s\"",
5204             sub);
5205           goto EXPAND_FAILED;
5206           }
5207
5208         /* Convert the address to binary integer(s) and apply the mask */
5209
5210         sub[maskoffset] = 0;
5211         count = host_aton(sub, binary);
5212         host_mask(count, binary, mask);
5213
5214         /* Convert to masked textual format and add to output. */
5215
5216         yield = string_cat(yield, &size, &ptr, buffer,
5217           host_nmtoa(count, binary, mask, buffer, '.'));
5218         continue;
5219         }
5220
5221       case EOP_ADDRESS:
5222       case EOP_LOCAL_PART:
5223       case EOP_DOMAIN:
5224         {
5225         uschar *error;
5226         int start, end, domain;
5227         uschar *t = parse_extract_address(sub, &error, &start, &end, &domain,
5228           FALSE);
5229         if (t != NULL)
5230           {
5231           if (c != EOP_DOMAIN)
5232             {
5233             if (c == EOP_LOCAL_PART && domain != 0) end = start + domain - 1;
5234             yield = string_cat(yield, &size, &ptr, sub+start, end-start);
5235             }
5236           else if (domain != 0)
5237             {
5238             domain += start;
5239             yield = string_cat(yield, &size, &ptr, sub+domain, end-domain);
5240             }
5241           }
5242         continue;
5243         }
5244
5245       case EOP_ADDRESSES:
5246         {
5247         uschar outsep[2] = { ':', '\0' };
5248         uschar *address, *error;
5249         int save_ptr = ptr;
5250         int start, end, domain;  /* Not really used */
5251
5252         while (isspace(*sub)) sub++;
5253         if (*sub == '>') { *outsep = *++sub; ++sub; }
5254         parse_allow_group = TRUE;
5255
5256         for (;;)
5257           {
5258           uschar *p = parse_find_address_end(sub, FALSE);
5259           uschar saveend = *p;
5260           *p = '\0';
5261           address = parse_extract_address(sub, &error, &start, &end, &domain,
5262             FALSE);
5263           *p = saveend;
5264
5265           /* Add the address to the output list that we are building. This is
5266           done in chunks by searching for the separator character. At the
5267           start, unless we are dealing with the first address of the output
5268           list, add in a space if the new address begins with the separator
5269           character, or is an empty string. */
5270
5271           if (address != NULL)
5272             {
5273             if (ptr != save_ptr && address[0] == *outsep)
5274               yield = string_cat(yield, &size, &ptr, US" ", 1);
5275
5276             for (;;)
5277               {
5278               size_t seglen = Ustrcspn(address, outsep);
5279               yield = string_cat(yield, &size, &ptr, address, seglen + 1);
5280
5281               /* If we got to the end of the string we output one character
5282               too many. */
5283
5284               if (address[seglen] == '\0') { ptr--; break; }
5285               yield = string_cat(yield, &size, &ptr, outsep, 1);
5286               address += seglen + 1;
5287               }
5288
5289             /* Output a separator after the string: we will remove the
5290             redundant final one at the end. */
5291
5292             yield = string_cat(yield, &size, &ptr, outsep, 1);
5293             }
5294
5295           if (saveend == '\0') break;
5296           sub = p + 1;
5297           }
5298
5299         /* If we have generated anything, remove the redundant final
5300         separator. */
5301
5302         if (ptr != save_ptr) ptr--;
5303         parse_allow_group = FALSE;
5304         continue;
5305         }
5306
5307
5308       /* quote puts a string in quotes if it is empty or contains anything
5309       other than alphamerics, underscore, dot, or hyphen.
5310
5311       quote_local_part puts a string in quotes if RFC 2821/2822 requires it to
5312       be quoted in order to be a valid local part.
5313
5314       In both cases, newlines and carriage returns are converted into \n and \r
5315       respectively */
5316
5317       case EOP_QUOTE:
5318       case EOP_QUOTE_LOCAL_PART:
5319       if (arg == NULL)
5320         {
5321         BOOL needs_quote = (*sub == 0);      /* TRUE for empty string */
5322         uschar *t = sub - 1;
5323
5324         if (c == EOP_QUOTE)
5325           {
5326           while (!needs_quote && *(++t) != 0)
5327             needs_quote = !isalnum(*t) && !strchr("_-.", *t);
5328           }
5329         else  /* EOP_QUOTE_LOCAL_PART */
5330           {
5331           while (!needs_quote && *(++t) != 0)
5332             needs_quote = !isalnum(*t) &&
5333               strchr("!#$%&'*+-/=?^_`{|}~", *t) == NULL &&
5334               (*t != '.' || t == sub || t[1] == 0);
5335           }
5336
5337         if (needs_quote)
5338           {
5339           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5340           t = sub - 1;
5341           while (*(++t) != 0)
5342             {
5343             if (*t == '\n')
5344               yield = string_cat(yield, &size, &ptr, US"\\n", 2);
5345             else if (*t == '\r')
5346               yield = string_cat(yield, &size, &ptr, US"\\r", 2);
5347             else
5348               {
5349               if (*t == '\\' || *t == '"')
5350                 yield = string_cat(yield, &size, &ptr, US"\\", 1);
5351               yield = string_cat(yield, &size, &ptr, t, 1);
5352               }
5353             }
5354           yield = string_cat(yield, &size, &ptr, US"\"", 1);
5355           }
5356         else yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5357         continue;
5358         }
5359
5360       /* quote_lookuptype does lookup-specific quoting */
5361
5362       else
5363         {
5364         int n;
5365         uschar *opt = Ustrchr(arg, '_');
5366
5367         if (opt != NULL) *opt++ = 0;
5368
5369         n = search_findtype(arg, Ustrlen(arg));
5370         if (n < 0)
5371           {
5372           expand_string_message = search_error_message;
5373           goto EXPAND_FAILED;
5374           }
5375
5376         if (lookup_list[n].quote != NULL)
5377           sub = (lookup_list[n].quote)(sub, opt);
5378         else if (opt != NULL) sub = NULL;
5379
5380         if (sub == NULL)
5381           {
5382           expand_string_message = string_sprintf(
5383             "\"%s\" unrecognized after \"${quote_%s\"",
5384             opt, arg);
5385           goto EXPAND_FAILED;
5386           }
5387
5388         yield = string_cat(yield, &size, &ptr, sub, Ustrlen(sub));
5389         continue;
5390         }
5391
5392       /* rx quote sticks in \ before any non-alphameric character so that
5393       the insertion works in a regular expression. */
5394
5395       case EOP_RXQUOTE:
5396         {
5397         uschar *t = sub - 1;
5398         while (*(++t) != 0)
5399           {
5400           if (!isalnum(*t))
5401             yield = string_cat(yield, &size, &ptr, US"\\", 1);
5402           yield = string_cat(yield, &size, &ptr, t, 1);
5403           }
5404         continue;
5405         }
5406
5407       /* RFC 2047 encodes, assuming headers_charset (default ISO 8859-1) as
5408       prescribed by the RFC, if there are characters that need to be encoded */
5409
5410       case EOP_RFC2047:
5411         {
5412         uschar buffer[2048];
5413         uschar *string = parse_quote_2047(sub, Ustrlen(sub), headers_charset,
5414           buffer, sizeof(buffer), FALSE);
5415         yield = string_cat(yield, &size, &ptr, string, Ustrlen(string));
5416         continue;
5417         }
5418
5419       /* RFC 2047 decode */
5420
5421       case EOP_RFC2047D:
5422         {
5423         int len;
5424         uschar *error;
5425         uschar *decoded = rfc2047_decode(sub, check_rfc2047_length,
5426           headers_charset, '?', &len, &error);
5427         if (error != NULL)
5428           {
5429           expand_string_message = error;
5430           goto EXPAND_FAILED;
5431           }
5432         yield = string_cat(yield, &size, &ptr, decoded, len);
5433         continue;
5434         }
5435
5436       /* from_utf8 converts UTF-8 to 8859-1, turning non-existent chars into
5437       underscores */
5438
5439       case EOP_FROM_UTF8:
5440         {
5441         while (*sub != 0)
5442           {
5443           int c;
5444           uschar buff[4];
5445           GETUTF8INC(c, sub);
5446           if (c > 255) c = '_';
5447           buff[0] = c;
5448           yield = string_cat(yield, &size, &ptr, buff, 1);
5449           }
5450         continue;
5451         }
5452
5453       /* escape turns all non-printing characters into escape sequences. */
5454
5455       case EOP_ESCAPE:
5456         {
5457         uschar *t = string_printing(sub);
5458         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5459         continue;
5460         }
5461
5462       /* Handle numeric expression evaluation */
5463
5464       case EOP_EVAL:
5465       case EOP_EVAL10:
5466         {
5467         uschar *save_sub = sub;
5468         uschar *error = NULL;
5469         int n = eval_expr(&sub, (c == EOP_EVAL10), &error, FALSE);
5470         if (error != NULL)
5471           {
5472           expand_string_message = string_sprintf("error in expression "
5473             "evaluation: %s (after processing \"%.*s\")", error, sub-save_sub,
5474               save_sub);
5475           goto EXPAND_FAILED;
5476           }
5477         sprintf(CS var_buffer, "%d", n);
5478         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5479         continue;
5480         }
5481
5482       /* Handle time period formating */
5483
5484       case EOP_TIME_EVAL:
5485         {
5486         int n = readconf_readtime(sub, 0, FALSE);
5487         if (n < 0)
5488           {
5489           expand_string_message = string_sprintf("string \"%s\" is not an "
5490             "Exim time interval in \"%s\" operator", sub, name);
5491           goto EXPAND_FAILED;
5492           }
5493         sprintf(CS var_buffer, "%d", n);
5494         yield = string_cat(yield, &size, &ptr, var_buffer, Ustrlen(var_buffer));
5495         continue;
5496         }
5497
5498       case EOP_TIME_INTERVAL:
5499         {
5500         int n;
5501         uschar *t = read_number(&n, sub);
5502         if (*t != 0) /* Not A Number*/
5503           {
5504           expand_string_message = string_sprintf("string \"%s\" is not a "
5505             "positive number in \"%s\" operator", sub, name);
5506           goto EXPAND_FAILED;
5507           }
5508         t = readconf_printtime(n);
5509         yield = string_cat(yield, &size, &ptr, t, Ustrlen(t));
5510         continue;
5511         }
5512
5513       /* Convert string to base64 encoding */
5514
5515       case EOP_STR2B64:
5516         {
5517         uschar *encstr = auth_b64encode(sub, Ustrlen(sub));
5518         yield = string_cat(yield, &size, &ptr, encstr, Ustrlen(encstr));
5519         continue;
5520         }
5521
5522       /* strlen returns the length of the string */
5523
5524       case EOP_STRLEN:
5525         {
5526         uschar buff[24];
5527         (void)sprintf(CS buff, "%d", Ustrlen(sub));
5528         yield = string_cat(yield, &size, &ptr, buff, Ustrlen(buff));
5529         continue;
5530         }
5531
5532       /* length_n or l_n takes just the first n characters or the whole string,
5533       whichever is the shorter;
5534
5535       substr_m_n, and s_m_n take n characters from offset m; negative m take
5536       from the end; l_n is synonymous with s_0_n. If n is omitted in substr it
5537       takes the rest, either to the right or to the left.
5538
5539       hash_n or h_n makes a hash of length n from the string, yielding n
5540       characters from the set a-z; hash_n_m makes a hash of length n, but
5541       uses m characters from the set a-zA-Z0-9.
5542
5543       nhash_n returns a single number between 0 and n-1 (in text form), while
5544       nhash_n_m returns a div/mod hash as two numbers "a/b". The first lies
5545       between 0 and n-1 and the second between 0 and m-1. */
5546
5547       case EOP_LENGTH:
5548       case EOP_L:
5549       case EOP_SUBSTR:
5550       case EOP_S:
5551       case EOP_HASH:
5552       case EOP_H:
5553       case EOP_NHASH:
5554       case EOP_NH:
5555         {
5556         int sign = 1;
5557         int value1 = 0;
5558         int value2 = -1;
5559         int *pn;
5560         int len;
5561         uschar *ret;
5562
5563         if (arg == NULL)
5564           {
5565           expand_string_message = string_sprintf("missing values after %s",
5566             name);
5567           goto EXPAND_FAILED;
5568           }
5569
5570         /* "length" has only one argument, effectively being synonymous with
5571         substr_0_n. */
5572
5573         if (c == EOP_LENGTH || c == EOP_L)
5574           {
5575           pn = &value2;
5576           value2 = 0;
5577           }
5578
5579         /* The others have one or two arguments; for "substr" the first may be
5580         negative. The second being negative means "not supplied". */
5581
5582         else
5583           {
5584           pn = &value1;
5585           if (name[0] == 's' && *arg == '-') { sign = -1; arg++; }
5586           }
5587
5588         /* Read up to two numbers, separated by underscores */
5589
5590         ret = arg;
5591         while (*arg != 0)
5592           {
5593           if (arg != ret && *arg == '_' && pn == &value1)
5594             {
5595             pn = &value2;
5596             value2 = 0;
5597             if (arg[1] != 0) arg++;
5598             }
5599           else if (!isdigit(*arg))
5600             {
5601             expand_string_message =
5602               string_sprintf("non-digit after underscore in \"%s\"", name);
5603             goto EXPAND_FAILED;
5604             }
5605           else *pn = (*pn)*10 + *arg++ - '0';
5606           }
5607         value1 *= sign;
5608
5609         /* Perform the required operation */
5610
5611         ret =
5612           (c == EOP_HASH || c == EOP_H)?
5613              compute_hash(sub, value1, value2, &len) :
5614           (c == EOP_NHASH || c == EOP_NH)?
5615              compute_nhash(sub, value1, value2, &len) :
5616              extract_substr(sub, value1, value2, &len);
5617
5618         if (ret == NULL) goto EXPAND_FAILED;
5619         yield = string_cat(yield, &size, &ptr, ret, len);
5620         continue;
5621         }
5622
5623       /* Stat a path */
5624
5625       case EOP_STAT:
5626         {
5627         uschar *s;
5628         uschar smode[12];
5629         uschar **modetable[3];
5630         int i;
5631         mode_t mode;
5632         struct stat st;
5633
5634         if ((expand_forbid & RDO_EXISTS) != 0)
5635           {
5636           expand_string_message = US"Use of the stat() expansion is not permitted";
5637           goto EXPAND_FAILED;
5638           }
5639
5640         if (stat(CS sub, &st) < 0)
5641           {
5642           expand_string_message = string_sprintf("stat(%s) failed: %s",
5643             sub, strerror(errno));
5644           goto EXPAND_FAILED;
5645           }
5646         mode = st.st_mode;
5647         switch (mode & S_IFMT)
5648           {
5649           case S_IFIFO: smode[0] = 'p'; break;
5650           case S_IFCHR: smode[0] = 'c'; break;
5651           case S_IFDIR: smode[0] = 'd'; break;
5652           case S_IFBLK: smode[0] = 'b'; break;
5653           case S_IFREG: smode[0] = '-'; break;
5654           default: smode[0] = '?'; break;
5655           }
5656
5657         modetable[0] = ((mode & 01000) == 0)? mtable_normal : mtable_sticky;
5658         modetable[1] = ((mode & 02000) == 0)? mtable_normal : mtable_setid;
5659         modetable[2] = ((mode & 04000) == 0)? mtable_normal : mtable_setid;
5660
5661         for (i = 0; i < 3; i++)
5662           {
5663           memcpy(CS(smode + 7 - i*3), CS(modetable[i][mode & 7]), 3);
5664           mode >>= 3;
5665           }
5666
5667         smode[10] = 0;
5668         s = string_sprintf("mode=%04lo smode=%s inode=%ld device=%ld links=%ld "
5669           "uid=%ld gid=%ld size=" OFF_T_FMT " atime=%ld mtime=%ld ctime=%ld",
5670           (long)(st.st_mode & 077777), smode, (long)st.st_ino,
5671           (long)st.st_dev, (long)st.st_nlink, (long)st.st_uid,
5672           (long)st.st_gid, st.st_size, (long)st.st_atime,
5673           (long)st.st_mtime, (long)st.st_ctime);
5674         yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
5675         continue;
5676         }
5677
5678       /* Unknown operator */
5679
5680       default:
5681       expand_string_message =
5682         string_sprintf("unknown expansion operator \"%s\"", name);
5683       goto EXPAND_FAILED;
5684       }
5685     }
5686
5687   /* Handle a plain name. If this is the first thing in the expansion, release
5688   the pre-allocated buffer. If the result data is known to be in a new buffer,
5689   newsize will be set to the size of that buffer, and we can just point at that
5690   store instead of copying. Many expansion strings contain just one reference,
5691   so this is a useful optimization, especially for humungous headers
5692   ($message_headers). */
5693
5694   if (*s++ == '}')
5695     {
5696     int len;
5697     int newsize = 0;
5698     if (ptr == 0)
5699       {
5700       store_reset(yield);
5701       yield = NULL;
5702       size = 0;
5703       }
5704     value = find_variable(name, FALSE, skipping, &newsize);
5705     if (value == NULL)
5706       {
5707       expand_string_message =
5708         string_sprintf("unknown variable in \"${%s}\"", name);
5709       check_variable_error_message(name);
5710       goto EXPAND_FAILED;
5711       }
5712     len = Ustrlen(value);
5713     if (yield == NULL && newsize != 0)
5714       {
5715       yield = value;
5716       size = newsize;
5717       ptr = len;
5718       }
5719     else yield = string_cat(yield, &size, &ptr, value, len);
5720     continue;
5721     }
5722
5723   /* Else there's something wrong */
5724
5725   expand_string_message =
5726     string_sprintf("\"${%s\" is not a known operator (or a } is missing "
5727     "in a variable reference)", name);
5728   goto EXPAND_FAILED;
5729   }
5730
5731 /* If we hit the end of the string when ket_ends is set, there is a missing
5732 terminating brace. */
5733
5734 if (ket_ends && *s == 0)
5735   {
5736   expand_string_message = malformed_header?
5737     US"missing } at end of string - could be header name not terminated by colon"
5738     :
5739     US"missing } at end of string";
5740   goto EXPAND_FAILED;
5741   }
5742
5743 /* Expansion succeeded; yield may still be NULL here if nothing was actually
5744 added to the string. If so, set up an empty string. Add a terminating zero. If
5745 left != NULL, return a pointer to the terminator. */
5746
5747 if (yield == NULL) yield = store_get(1);
5748 yield[ptr] = 0;
5749 if (left != NULL) *left = s;
5750
5751 /* Any stacking store that was used above the final string is no longer needed.
5752 In many cases the final string will be the first one that was got and so there
5753 will be optimal store usage. */
5754
5755 store_reset(yield + ptr + 1);
5756 DEBUG(D_expand)
5757   {
5758   debug_printf("expanding: %.*s\n   result: %s\n", (int)(s - string), string,
5759     yield);
5760   if (skipping) debug_printf("skipping: result is not used\n");
5761   }
5762 return yield;
5763
5764 /* This is the failure exit: easiest to program with a goto. We still need
5765 to update the pointer to the terminator, for cases of nested calls with "fail".
5766 */
5767
5768 EXPAND_FAILED_CURLY:
5769 expand_string_message = malformed_header?
5770   US"missing or misplaced { or } - could be header name not terminated by colon"
5771   :
5772   US"missing or misplaced { or }";
5773
5774 /* At one point, Exim reset the store to yield (if yield was not NULL), but
5775 that is a bad idea, because expand_string_message is in dynamic store. */
5776
5777 EXPAND_FAILED:
5778 if (left != NULL) *left = s;
5779 DEBUG(D_expand)
5780   {
5781   debug_printf("failed to expand: %s\n", string);
5782   debug_printf("   error message: %s\n", expand_string_message);
5783   if (expand_string_forcedfail) debug_printf("failure was forced\n");
5784   }
5785 return NULL;
5786 }
5787
5788
5789 /* This is the external function call. Do a quick check for any expansion
5790 metacharacters, and if there are none, just return the input string.
5791
5792 Argument: the string to be expanded
5793 Returns:  the expanded string, or NULL if expansion failed; if failure was
5794           due to a lookup deferring, search_find_defer will be TRUE
5795 */
5796
5797 uschar *
5798 expand_string(uschar *string)
5799 {
5800 search_find_defer = FALSE;
5801 malformed_header = FALSE;
5802 return (Ustrpbrk(string, "$\\") == NULL)? string :
5803   expand_string_internal(string, FALSE, NULL, FALSE);
5804 }
5805
5806
5807
5808 /*************************************************
5809 *              Expand and copy                   *
5810 *************************************************/
5811
5812 /* Now and again we want to expand a string and be sure that the result is in a
5813 new bit of store. This function does that.
5814
5815 Argument: the string to be expanded
5816 Returns:  the expanded string, always in a new bit of store, or NULL
5817 */
5818
5819 uschar *
5820 expand_string_copy(uschar *string)
5821 {
5822 uschar *yield = expand_string(string);
5823 if (yield == string) yield = string_copy(string);
5824 return yield;
5825 }
5826
5827
5828
5829 /*************************************************
5830 *        Expand and interpret as an integer      *
5831 *************************************************/
5832
5833 /* Expand a string, and convert the result into an integer.
5834
5835 Arguments:
5836   string  the string to be expanded
5837   isplus  TRUE if a non-negative number is expected
5838
5839 Returns:  the integer value, or
5840           -1 for an expansion error               ) in both cases, message in
5841           -2 for an integer interpretation error  ) expand_string_message
5842           expand_string_message is set NULL for an OK integer
5843 */
5844
5845 int
5846 expand_string_integer(uschar *string, BOOL isplus)
5847 {
5848 long int value;
5849 uschar *s = expand_string(string);
5850 uschar *msg = US"invalid integer \"%s\"";
5851 uschar *endptr;
5852
5853 /* If expansion failed, expand_string_message will be set. */
5854
5855 if (s == NULL) return -1;
5856
5857 /* On an overflow, strtol() returns LONG_MAX or LONG_MIN, and sets errno
5858 to ERANGE. When there isn't an overflow, errno is not changed, at least on some
5859 systems, so we set it zero ourselves. */
5860
5861 errno = 0;
5862 expand_string_message = NULL;               /* Indicates no error */
5863 value = strtol(CS s, CSS &endptr, 10);
5864
5865 if (endptr == s)
5866   {
5867   msg = US"integer expected but \"%s\" found";
5868   }
5869 else if (value < 0 && isplus)
5870   {
5871   msg = US"non-negative integer expected but \"%s\" found";
5872   }
5873 else
5874   {
5875   /* Ensure we can cast this down to an int */
5876   if (value > INT_MAX  || value < INT_MIN) errno = ERANGE;
5877
5878   if (errno != ERANGE)
5879     {
5880     if (tolower(*endptr) == 'k')
5881       {
5882       if (value > INT_MAX/1024 || value < INT_MIN/1024) errno = ERANGE;
5883         else value *= 1024;
5884       endptr++;
5885       }
5886     else if (tolower(*endptr) == 'm')
5887       {
5888       if (value > INT_MAX/(1024*1024) || value < INT_MIN/(1024*1024))
5889         errno = ERANGE;
5890       else value *= 1024*1024;
5891       endptr++;
5892       }
5893     }
5894   if (errno == ERANGE)
5895     msg = US"absolute value of integer \"%s\" is too large (overflow)";
5896   else
5897     {
5898     while (isspace(*endptr)) endptr++;
5899     if (*endptr == 0) return (int)value;
5900     }
5901   }
5902
5903 expand_string_message = string_sprintf(CS msg, s);
5904 return -2;
5905 }
5906
5907
5908 /*************************************************
5909 **************************************************
5910 *             Stand-alone test program           *
5911 **************************************************
5912 *************************************************/
5913
5914 #ifdef STAND_ALONE
5915
5916
5917 BOOL
5918 regex_match_and_setup(const pcre *re, uschar *subject, int options, int setup)
5919 {
5920 int ovector[3*(EXPAND_MAXN+1)];
5921 int n = pcre_exec(re, NULL, subject, Ustrlen(subject), 0, PCRE_EOPT|options,
5922   ovector, sizeof(ovector)/sizeof(int));
5923 BOOL yield = n >= 0;
5924 if (n == 0) n = EXPAND_MAXN + 1;
5925 if (yield)
5926   {
5927   int nn;
5928   expand_nmax = (setup < 0)? 0 : setup + 1;
5929   for (nn = (setup < 0)? 0 : 2; nn < n*2; nn += 2)
5930     {
5931     expand_nstring[expand_nmax] = subject + ovector[nn];
5932     expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
5933     }
5934   expand_nmax--;
5935   }
5936 return yield;
5937 }
5938
5939
5940 int main(int argc, uschar **argv)
5941 {
5942 int i;
5943 uschar buffer[1024];
5944
5945 debug_selector = D_v;
5946 debug_file = stderr;
5947 debug_fd = fileno(debug_file);
5948 big_buffer = malloc(big_buffer_size);
5949
5950 for (i = 1; i < argc; i++)
5951   {
5952   if (argv[i][0] == '+')
5953     {
5954     debug_trace_memory = 2;
5955     argv[i]++;
5956     }
5957   if (isdigit(argv[i][0]))
5958     debug_selector = Ustrtol(argv[i], NULL, 0);
5959   else
5960     if (Ustrspn(argv[i], "abcdefghijklmnopqrtsuvwxyz0123456789-.:/") ==
5961         Ustrlen(argv[i]))
5962       {
5963       #ifdef LOOKUP_LDAP
5964       eldap_default_servers = argv[i];
5965       #endif
5966       #ifdef LOOKUP_MYSQL
5967       mysql_servers = argv[i];
5968       #endif
5969       #ifdef LOOKUP_PGSQL
5970       pgsql_servers = argv[i];
5971       #endif
5972       }
5973   #ifdef EXIM_PERL
5974   else opt_perl_startup = argv[i];
5975   #endif
5976   }
5977
5978 printf("Testing string expansion: debug_level = %d\n\n", debug_level);
5979
5980 expand_nstring[1] = US"string 1....";
5981 expand_nlength[1] = 8;
5982 expand_nmax = 1;
5983
5984 #ifdef EXIM_PERL
5985 if (opt_perl_startup != NULL)
5986   {
5987   uschar *errstr;
5988   printf("Starting Perl interpreter\n");
5989   errstr = init_perl(opt_perl_startup);
5990   if (errstr != NULL)
5991     {
5992     printf("** error in perl_startup code: %s\n", errstr);
5993     return EXIT_FAILURE;
5994     }
5995   }
5996 #endif /* EXIM_PERL */
5997
5998 while (fgets(buffer, sizeof(buffer), stdin) != NULL)
5999   {
6000   void *reset_point = store_get(0);
6001   uschar *yield = expand_string(buffer);
6002   if (yield != NULL)
6003     {
6004     printf("%s\n", yield);
6005     store_reset(reset_point);
6006     }
6007   else
6008     {
6009     if (search_find_defer) printf("search_find deferred\n");
6010     printf("Failed: %s\n", expand_string_message);
6011     if (expand_string_forcedfail) printf("Forced failure\n");
6012     printf("\n");
6013     }
6014   }
6015
6016 search_tidyup();
6017
6018 return 0;
6019 }
6020
6021 #endif
6022
6023 /* End of expand.c */