src/src/rewrite.c

   1 /* $Cambridge: exim/src/src/rewrite.c,v 1.3 2006/02/07 11:19:00 ph10 Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) University of Cambridge 1995 - 2006 */
   8 /* See the file NOTICE for conditions of use and distribution. */
   9
  10 /* Functions concerned with rewriting headers */
  11
  12
  13 #include "exim.h"
  14
  15 /* Names for testing rewriting */
  16
  17 static char *rrname[] = {
  18   "  sender",
  19   "    from",
  20   "      to",
  21   "      cc",
  22   "     bcc",
  23   "reply-to",
  24   "env-from",
  25   "  env-to"
  26 };
  27
  28 /* Structure and table for finding source of address for debug printing */
  29
  30 typedef struct where_list_block {
  31   int bit;
  32   uschar *string;
  33 } where_list_block;
  34
  35 static where_list_block where_list[] = {
  36   { rewrite_sender,  US"sender:" },
  37   { rewrite_from,    US"from:" },
  38   { rewrite_to,      US"to:" },
  39   { rewrite_cc,      US"cc:" },
  40   { rewrite_bcc,     US"bcc:" },
  41   { rewrite_replyto, US"reply-to:" },
  42   { rewrite_envfrom, US"env-from" },
  43   { rewrite_envto,   US"env-to" },
  44   { rewrite_smtp,    US"smtp recipient" },
  45   { rewrite_smtp|rewrite_smtp_sender, US"smtp sender" }
  46 };
  47
  48 static int where_list_size = sizeof(where_list)/sizeof(where_list_block);
  49
  50
  51
  52 /*************************************************
  53 *            Ensure an address is qualified      *
  54 *************************************************/
  55
  56 /*
  57 Arguments:
  58   s              address to check
  59   is_recipient   TRUE if a recipient address; FALSE if a sender address
  60
  61 Returns:         fully-qualified address
  62 */
  63
  64 uschar *
  65 rewrite_address_qualify(uschar *s, BOOL is_recipient)
  66 {
  67 return (parse_find_at(s) != NULL)? s :
  68   string_sprintf("%s@%s", s,
  69     is_recipient? qualify_domain_recipient : qualify_domain_sender);
  70 }
  71
  72
  73
  74 /*************************************************
  75 *               Rewrite a single address         *
  76 *************************************************/
  77
  78 /* The yield is the input address if there is no rewriting to be done. Assume
  79 the input is a valid address, except in the case of SMTP-time rewriting, which
  80 is handled specially. When this function is called while processing filter and
  81 forward files, the uid may be that of the user. Ensure it is reset while
  82 expanding a replacement, in case that involves file lookups.
  83
  84 Arguments:
  85   s              address to rewrite
  86   flag           indicates where this address comes from; it must match the
  87                    flags in the rewriting rule
  88   whole          if not NULL, set TRUE if any rewriting rule contained the
  89                    "whole" bit and it is a header that is being rewritten
  90   add_header     if TRUE and rewriting occurs, add an "X-rewrote-xxx" header
  91                    if headers are in existence; this should be TRUE only when
  92                    a message is being received, not during delivery
  93   name           name of header, for use when adding X-rewrote-xxxx
  94   rewrite_rules  chain of rewriting rules
  95
  96 Returns:         new address if rewritten; the input address if no change;
  97                  for a header rewrite, if the "whole" bit is set, the entire
  98                  rewritten address is returned, not just the active bit.
  99 */
 100
 101 uschar *
 102 rewrite_one(uschar *s, int flag, BOOL *whole, BOOL add_header, uschar *name,
 103   rewrite_rule *rewrite_rules)
 104 {
 105 rewrite_rule *rule;
 106 uschar *yield = s;
 107 uschar *subject = s;
 108 uschar *domain = NULL;
 109 BOOL done = FALSE;
 110 int rule_number = 1;
 111 int yield_start = 0, yield_end = 0;
 112
 113 if (whole != NULL) *whole = FALSE;
 114
 115 /* Scan the rewriting rules */
 116
 117 for (rule = rewrite_rules;
 118      rule != NULL && !done;
 119      rule_number++, rule = rule->next)
 120   {
 121   int start, end, pdomain;
 122   int count = 0;
 123   uschar *save_localpart, *save_domain;
 124   uschar *error, *new, *newparsed;
 125
 126   /* Ensure that the flag matches the flags in the rule. */
 127
 128   if ((rule->flags & flag) == 0) continue;
 129
 130   /* Come back here for a repeat after a successful rewrite. We do this
 131   only so many times. */
 132
 133   REPEAT_RULE:
 134
 135   /* If this is an SMTP-time rewrite, the pattern must be a regex and
 136   the subject may have any structure. No local part or domain variables
 137   can be set for the expansion. We expand the pattern in order to be consistent
 138   with the other kinds of rewrite, where expansion happens inside
 139   match_address_list(). */
 140
 141   if ((flag & rewrite_smtp) != 0)
 142     {
 143     uschar *key = expand_string(rule->key);
 144     if (key == NULL)
 145       {
 146       if (!expand_string_forcedfail)
 147         log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand \"%s\" while "
 148           "checking for SMTP rewriting: %s", rule->key, expand_string_message);
 149       continue;
 150       }
 151     if (match_check_string(subject, key, 0, TRUE, FALSE, FALSE, NULL) != OK)
 152       continue;
 153     new = expand_string(rule->replacement);
 154     }
 155
 156   /* All other rewrites expect the input to be a valid address, so local part
 157   and domain variables can be set for expansion. For the first rule, to be
 158   applied to this address, domain will be NULL and needs to be set. */
 159
 160   else
 161     {
 162     if (domain == NULL) domain = Ustrrchr(subject, '@') + 1;
 163
 164     /* Use the general function for matching an address against a list (here
 165     just one item, so use the "impossible value" separator UCHAR_MAX+1). */
 166
 167     if (match_address_list(subject, FALSE, TRUE, &(rule->key), NULL, 0,
 168         UCHAR_MAX + 1, NULL) != OK)
 169       continue;
 170
 171     /* The source address matches, and numerical variables have been
 172     set up. If the replacement string consists of precisely "*" then no
 173     rewriting is required for this address - the behaviour is as for "fail"
 174     in the replacement expansion, but assuming the quit flag. */
 175
 176     if (Ustrcmp(rule->replacement, "*") == 0) break;
 177
 178     /* Otherwise, expand the replacement string. Set $local_part and $domain to
 179     the appropriate values, restoring whatever value they previously had
 180     afterwards. */
 181
 182     save_localpart = deliver_localpart;
 183     save_domain = deliver_domain;
 184
 185     /* We have subject pointing to "localpart@domain" and domain pointing to
 186     the domain. Temporarily terminate the local part so that it can be
 187     set up as an expansion variable */
 188
 189     domain[-1] = 0;
 190     deliver_localpart = subject;
 191     deliver_domain = domain;
 192
 193     new = expand_string(rule->replacement);
 194
 195     domain[-1] = '@';
 196     deliver_localpart = save_localpart;
 197     deliver_domain = save_domain;
 198     }
 199
 200   /* If the expansion failed with the "forcedfail" flag, don't generate
 201   an error - just give up on this rewriting rule. If the "q" flag is set,
 202   give up altogether. For other expansion failures we have a configuration
 203   error. */
 204
 205   if (new == NULL)
 206     {
 207     if (expand_string_forcedfail)
 208       { if ((rule->flags & rewrite_quit) != 0) break; else continue; }
 209     log_write(0, LOG_MAIN|LOG_PANIC, "Expansion of %s failed while rewriting: "
 210       "%s", rule->replacement, expand_string_message);
 211     break;
 212     }
 213
 214   /* Check the what has been generated is a valid RFC 2822 address. Only
 215   envelope from or SMTP sender is permitted to be rewritten as <>.*/
 216
 217   newparsed = parse_extract_address(new, &error, &start, &end, &pdomain,
 218     flag == rewrite_envfrom || flag == (rewrite_smtp|rewrite_smtp_sender));
 219
 220   if (newparsed == NULL)
 221     {
 222     log_write(0, LOG_MAIN|LOG_PANIC, "Rewrite of %s yielded unparseable "
 223       "address: %s in address %s", subject, error, new);
 224     break;   /* Give up on this address */
 225     }
 226
 227   /* A non-null unqualified address can be qualified if requested. Otherwise,
 228   this is an error unless it's the empty address in circumstances where that is
 229   permitted. */
 230
 231   if (pdomain == 0 && (*newparsed != 0 ||
 232       (flag != rewrite_envfrom && flag != (rewrite_smtp|rewrite_smtp_sender))))
 233     {
 234     if ((rule->flags & rewrite_qualify) != 0)
 235       {
 236       newparsed = rewrite_address_qualify(newparsed, TRUE);
 237       new = string_sprintf("%.*s%s%.*s", start, new, newparsed,
 238         Ustrlen(new) - end, new + end);
 239       end = start + Ustrlen(newparsed);
 240       }
 241     else
 242       {
 243       log_write(0, LOG_MAIN|LOG_PANIC, "Rewrite of %s yielded unqualified "
 244         "address \"%s\"", subject, new);
 245       break;   /* Give up on this address */
 246       }
 247     }
 248
 249   /* We have a validly rewritten address */
 250
 251   if ((log_write_selector & L_address_rewrite) != 0 ||
 252       (debug_selector & D_rewrite) != 0)
 253     {
 254     int i;
 255     uschar *where = US"?";
 256
 257     for (i = 0; i < where_list_size; i++)
 258       {
 259       if (flag == where_list[i].bit)
 260         {
 261         where = where_list[i].string;
 262         break;
 263         }
 264       }
 265     log_write(L_address_rewrite,
 266            LOG_MAIN, "\"%s\" from %s rewritten as \"%s\" by rule %d",
 267            yield, where, new, rule_number);
 268     }
 269
 270   /* A header will only actually be added if header_last is non-NULL,
 271   i.e. during message reception or delivery, but add_header should not
 272   be set TRUE during delivery, as otherwise multiple instances of the header
 273   can fill up the -H file and make it embarrassingly large. We don't need
 274   to set header_rewritten because the -H file always gets written at the end
 275   of message reception. */
 276
 277   if (add_header)
 278     header_add(htype_old, "X-rewrote-%s: %s\n", name, subject);
 279
 280   /* Handle the case when replacement of the whole address is possible.
 281   This happens only when whole is not NULL and we are rewriting a header.
 282   If *whole is already TRUE it means that a previous rule had the w
 283   flag set and so we must preserve the non-active portion of the current
 284   subject unless the current rule also has the w flag set. */
 285
 286   if (whole != NULL && (flag & rewrite_all_headers) != 0)
 287     {
 288     /* Current rule has the w flag set. We must ensure the phrase parts
 289     are syntactically valid if they are present. */
 290
 291     if ((rule->flags & rewrite_whole) != 0)
 292       {
 293       if (start > 0 && new[start-1] == '<')
 294         {
 295         uschar *p1 = new + start - 1;
 296         uschar *p2 = new + end + 1;
 297         uschar *pf1, *pf2;
 298         uschar buff1[256], buff2[256];
 299
 300         while (p1 > new && p1[-1] == ' ') p1--;
 301         pf1 = parse_fix_phrase(new, p1 - new, buff1, sizeof(buff1));
 302         while (*p2 == ' ') p2++;
 303         pf2 = parse_fix_phrase(p2, Ustrlen(p2), buff2, sizeof(buff2));
 304
 305         /* Note that pf1 and pf2 are NOT necessarily buff1 and buff2. For
 306         a non-RFC 2047 phrase that does not need to be RFC 2822 quoted, they
 307         will be buff1+1 and buff2+1. */
 308
 309         start = Ustrlen(pf1) + start + new - p1;
 310         end = start + Ustrlen(newparsed);
 311         new = string_sprintf("%s%.*s%s", pf1, p2 - p1, p1, pf2);
 312         }
 313
 314       /* Now accept the whole thing */
 315
 316       yield = new;
 317       yield_start = start;
 318       yield_end = end;
 319       subject = newparsed;
 320       *whole = TRUE;
 321       }
 322
 323     /* Current rule does not have the w flag set; if not previously
 324     done any whole rewriting, behave in non-whole manner. */
 325
 326     else if (!*whole) goto NEVER_WHOLE;
 327
 328     /* Current rule does not have the w flag set, but a previous
 329     rule did rewrite the whole address. Thus yield and subject will be
 330     different. Preserve the previous non-active part of the address. */
 331
 332     else
 333       {
 334       subject = newparsed;
 335       new = string_sprintf("%.*s%s%n%s",
 336          yield_start, yield, subject, &end, yield + yield_end);
 337       yield_end = end;
 338       yield = new;
 339       }
 340     }
 341
 342   /* Rule just rewrites active part, or handling an envelope. This
 343   code is obeyed only when all rules so far have not done "whole"
 344   replacement. */
 345
 346   else
 347     {
 348     NEVER_WHOLE:
 349     subject = yield = newparsed;
 350     }
 351
 352   domain = NULL;    /* Reset for next rule */
 353
 354   /* If no further rewrites are to be done, set the done flag. This allows
 355   repeats of the current rule if configured before breaking the loop. */
 356
 357   if ((rule->flags & rewrite_quit) != 0) done = TRUE;
 358
 359   /* Allow the current rule to be applied up to 10 times if
 360   requested. */
 361
 362   if ((rule->flags & rewrite_repeat) != 0)
 363     {
 364     if (count++ < 10) goto REPEAT_RULE;
 365     log_write(0, LOG_MAIN|LOG_PANIC, "rewrite rule repeat ignored after 10 "
 366       "times");
 367     }
 368   }
 369
 370 /* Unset expansion numeric variables, and that's it. */
 371
 372 expand_nmax = -1;
 373 return yield;
 374 }
 375
 376
 377
 378 /*************************************************
 379 *         Ensure qualification and rewrite       *
 380 *************************************************/
 381
 382 /* This function is called for envelope addresses, the boolean specifying
 383 whether a recipient or a sender. It must first of all ensure the address is
 384 fully qualified, and then apply any relevant re-writing rules. The add-header
 385 flag causes a header to be added, recording the old address. This is marked
 386 "old", so that it is never transported anywhere; it exists for local checking
 387 and debugging purposes.
 388
 389 Arguments:
 390   s              the address to be considered
 391   is_recipient   TRUE for recipient addresses; FALSE otherwise
 392   add_header     add "X-rewrote-xxx" header when rewriting; this is
 393                    set TRUE only for calls from the reception functions
 394   rewrite_rules  points to chain of rewrite rules
 395   existflags     bits indicating which headers there are rewrites for
 396                  (just an optimisation)
 397
 398 Returns:         possibly rewritten address
 399 */
 400
 401 uschar *
 402 rewrite_address(uschar *s, BOOL is_recipient, BOOL add_header,
 403   rewrite_rule *rewrite_rules, int existflags)
 404 {
 405 int flag = is_recipient? rewrite_envto : rewrite_envfrom;
 406 s = rewrite_address_qualify(s, is_recipient);
 407 if ((existflags & flag) != 0)
 408   {
 409   uschar *new = rewrite_one(s, flag, NULL, add_header, is_recipient?
 410     US"original-recipient" : US"sender", rewrite_rules);
 411   if (new != s) s = new;
 412   }
 413 return s;
 414 }
 415
 416
 417
 418 /*************************************************
 419 *    Qualify and possibly rewrite one header     *
 420 *************************************************/
 421
 422 /* This is called only from rewrite_header() below, either when reading a
 423 message. or when routing, in order to rewrite addresses that get changed by a
 424 router. This is normally the addition of full qualification to a partial
 425 domain. The first rewriting rule in this case is "change routed_old into
 426 routed_new", and it applies to all header lines that contain addresses. Then
 427 header-specific rewriting rules are applied.
 428
 429 Before rewriting can be done, addresses without domains have to be qualified.
 430 This should only be done for messages from "local" senders. This is a difficult
 431 concept to pin down, what with the use of SMTP both as a submission and as a
 432 transmission protocol. Exim normally requires incoming SMTP to contain fully-
 433 qualified addresses, but there are options to permit unqualified ones from
 434 certain hosts. For those hosts only, addresses in headers can also be
 435 qualified. For other hosts, unqualified addresses in headers do not get touched
 436 in any way. For locally sourced messages, unqualified addresses always get
 437 qualified, except when -bnq is used to explicitly suppress this.
 438
 439 Arguments:
 440   h              pointer to header line block
 441   flag           indicates which header this is
 442   routed_old     if not NULL, this is a rewrite caused by a router, changing
 443                    this domain into routed_new
 444   routed_new     new routed domain if routed_old is not NULL
 445   rewrite_rules  points to chain of rewriting rules
 446   existflags     bits indicating which rewrites exist
 447   replace        if TRUE, insert the new header in the chain after the old
 448                    one, and mark the old one "replaced"
 449
 450 Returns:         NULL if header unchanged; otherwise the rewritten header
 451 */
 452
 453 static header_line *
 454 rewrite_one_header(header_line *h, int flag, uschar *routed_old,
 455   uschar *routed_new, rewrite_rule *rewrite_rules, int existflags, BOOL replace)
 456 {
 457 int lastnewline = 0;
 458 header_line *newh = NULL;
 459 void *function_reset_point = store_get(0);
 460 uschar *s = Ustrchr(h->text, ':') + 1;
 461 while (isspace(*s)) s++;
 462
 463 DEBUG(D_rewrite)
 464   debug_printf("rewrite_one_header: type=%c:\n  %s", h->type, h->text);
 465
 466 parse_allow_group = TRUE;     /* Allow group syntax */
 467
 468 /* Loop for multiple addresses in the header. We have to go through them all
 469 in case any need qualifying, even if there's no rewriting. Pathological headers
 470 may have thousands of addresses in them, so cause the store to be reset for
 471 any that don't actually get rewritten. We also play silly games for those that
 472 _are_ rewritten so as to avoid runaway store usage for these kinds of header.
 473 We want to avoid keeping store for any intermediate versions. */
 474
 475 while (*s != 0)
 476   {
 477   uschar *sprev;
 478   uschar *ss = parse_find_address_end(s, FALSE);
 479   uschar *recipient, *new, *errmess;
 480   void *loop_reset_point = store_get(0);
 481   BOOL changed = FALSE;
 482   int terminator = *ss;
 483   int start, end, domain;
 484
 485   /* Temporarily terminate the string at this point, and extract the
 486   operative address within. Then put back the terminator and prepare for
 487   the next address, saving the start of the old one. */
 488
 489   *ss = 0;
 490   recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
 491   *ss = terminator;
 492   sprev = s;
 493   s = ss + (terminator? 1:0);
 494   while (isspace(*s)) s++;
 495
 496   /* There isn't much we can do for syntactic disasters at this stage.
 497   Pro tem (possibly for ever) ignore them. */
 498
 499   if (recipient == NULL)
 500     {
 501     store_reset(loop_reset_point);
 502     continue;
 503     }
 504
 505   /* If routed_old is not NULL, this is a rewrite caused by a router,
 506   consisting of changing routed_old into routed_new, and applying to all
 507   headers. If the header address has no domain, it is excluded, since a router
 508   rewrite affects domains only. The new value should always be fully qualified,
 509   but it may be something that has an explicit re-write rule set, so we need to
 510   check the configured rules subsequently as well. (Example: there's an
 511   explicit rewrite turning *.foo.com into foo.com, and an address is supplied
 512   as abc@xyz, which the DNS lookup turns into abc@xyz.foo.com). However, if no
 513   change is made here, don't bother carrying on. */
 514
 515   if (routed_old != NULL)
 516     {
 517     if (domain <= 0 || strcmpic(recipient+domain, routed_old) != 0) continue;
 518     recipient[domain-1] = 0;
 519     new = string_sprintf("%s@%s", recipient, routed_new);
 520     DEBUG(D_rewrite)
 521       {
 522       recipient[domain-1] = '@';
 523       debug_printf("%s rewritten by router as %s\n", recipient, new);
 524       }
 525     recipient = new;
 526     changed = TRUE;
 527     }
 528
 529   /* This is not a router-inspired rewrite. Ensure the address is fully
 530   qualified if that is permitted. If an unqualified address was received
 531   from a host that isn't listed, do not continue rewriting this address.
 532   Sender, From or Reply-To headers are treated as senders, the rest as
 533   recipients. This matters only when there are different qualify strings. */
 534
 535   else
 536     {
 537     BOOL is_recipient =
 538       (flag & (rewrite_sender | rewrite_from | rewrite_replyto)) == 0;
 539     new = rewrite_address_qualify(recipient, is_recipient);
 540     changed = (new != recipient);
 541     recipient = new;
 542
 543     /* Can only qualify if permitted; if not, no rewrite. */
 544
 545     if (changed && ((is_recipient && !allow_unqualified_recipient) ||
 546                     (!is_recipient && !allow_unqualified_sender)))
 547       {
 548       store_reset(loop_reset_point);
 549       continue;
 550       }
 551     }
 552
 553   /* If there are rewrite rules for this type of header, apply
 554   them. This test is just for efficiency, to save scanning the rules
 555   in cases when nothing is going to change. If any rewrite rule had the
 556   "whole" flag set, adjust the pointers so that the whole address gets
 557   replaced, except possibly a final \n. */
 558
 559   if ((existflags & flag) != 0)
 560     {
 561     BOOL whole;
 562     new = rewrite_one(recipient, flag, &whole, FALSE, NULL, rewrite_rules);
 563     if (new != recipient)
 564       {
 565       changed = TRUE;
 566       if (whole)
 567         {
 568         start = 0;
 569         end = ss - sprev;
 570         if (sprev[end-1] == '\n') end--;
 571         }
 572       }
 573     }
 574
 575   /* If nothing has changed, lose all dynamic store obtained in this loop, and
 576   move on to the next address. We can't reset to the function start store
 577   point, because we may have a rewritten line from a previous time round the
 578   loop. */
 579
 580   if (!changed) store_reset(loop_reset_point);
 581
 582   /* If the address has changed, create a new header containing the
 583   rewritten address. We do not need to set the chain pointers at this
 584   stage. We want to avoid using more and more memory if the header is very long
 585   and contains lots and lots of rewritten addresses. Therefore, we build the
 586   new text string in malloc store, then at the end we reset dynamic store
 587   before copying the new header to a new block (and then freeing the malloc
 588   block). The header must end up in dynamic store so that it's freed at the end
 589   of receiving a message. */
 590
 591   else
 592     {
 593     int remlen;
 594     int newlen = Ustrlen(new);
 595     int oldlen = end - start;
 596
 597     header_line *prev = (newh == NULL)? h : newh;
 598     uschar *newt = store_malloc(prev->slen - oldlen + newlen + 4);
 599     uschar *newtstart = newt;
 600
 601     int type = prev->type;
 602     int slen = prev->slen - oldlen + newlen;
 603
 604     /* Build the new header text by copying the old and putting in the
 605     replacement. This process may make the header substantially longer
 606     than it was before - qualification of a list of bare addresses can
 607     often do this - so we stick in a newline after the re-written address
 608     if it has increased in length and ends more than 40 characters in. In
 609     fact, the code is not perfect, since it does not scan for existing
 610     newlines in the header, but it doesn't seem worth going to that
 611     amount of trouble. */
 612
 613     Ustrncpy(newt, prev->text, sprev - prev->text + start);
 614     newt += sprev - prev->text + start;
 615     *newt = 0;
 616     Ustrcat(newt, new);
 617     newt += newlen;
 618     remlen = s - (sprev + end);
 619     if (remlen > 0)
 620       {
 621       Ustrncpy(newt, sprev + end, remlen);
 622       newt += remlen;
 623       *newt = 0;
 624       }
 625
 626     /* Must check that there isn't a newline here anyway; in particular, there
 627     will be one at the very end of the header, where we DON'T want to insert
 628     another one! The pointer s has been skipped over white space, so just
 629     look back to see if the last non-space-or-tab was a newline. */
 630
 631     if (newlen > oldlen && newt - newtstart - lastnewline > 40)
 632       {
 633       uschar *p = s - 1;
 634       while (p >= prev->text && (*p == ' ' || *p == '\t')) p--;
 635       if (*p != '\n')
 636         {
 637         lastnewline = newt - newtstart;
 638         Ustrcat(newt, "\n\t");
 639         slen += 2;
 640         }
 641       }
 642
 643     /* Finally, the remaining unprocessed addresses, if any. */
 644
 645     Ustrcat(newt, s);
 646
 647     DEBUG(D_rewrite) debug_printf("newlen=%d newtype=%c newtext:\n%s",
 648       slen, type, newtstart);
 649
 650     /* Compute the length of the rest of the header line before we possibly
 651     flatten a previously rewritten copy. */
 652
 653     remlen = (s - prev->text) - oldlen + newlen;
 654
 655     /* We have the new text in a malloc block. That enables us to release all
 656     the memory that has been used, back to the point at which the function was
 657     entered. Then set up a new header in dynamic store. This will override a
 658     rewritten copy from a previous time round this loop. */
 659
 660     store_reset(function_reset_point);
 661     newh = store_get(sizeof(header_line));
 662     newh->type = type;
 663     newh->slen = slen;
 664     newh->text = string_copyn(newtstart, slen);
 665     store_free(newtstart);
 666
 667     /* Set up for scanning the rest of the header */
 668
 669     s = newh->text + remlen;
 670     DEBUG(D_rewrite) debug_printf("remainder: %s", (*s == 0)? US"\n" : s);
 671     }
 672   }
 673
 674 parse_allow_group = FALSE;  /* Reset group flags */
 675 parse_found_group = FALSE;
 676
 677 /* If a rewrite happened and "replace" is true, put the new header into the
 678 chain following the old one, and mark the old one as replaced. */
 679
 680 if (newh != NULL && replace)
 681   {
 682   newh->next = h->next;
 683   if (newh->next == NULL) header_last = newh;
 684   h->type = htype_old;
 685   h->next = newh;
 686   }
 687
 688 return newh;
 689 }
 690
 691
 692
 693
 694 /*************************************************
 695 *              Rewrite a header line             *
 696 *************************************************/
 697
 698 /* This function may be passed any old header line. It must detect those which
 699 contain addresses, then then apply any rewriting rules that apply. If
 700 routed_old is NULL, only the configured rewriting rules are consulted.
 701 Otherwise, the rewriting rule is "change routed_old into routed_new", and it
 702 applies to all header lines that contain addresses. Then header-specific
 703 rewriting rules are applied.
 704
 705 The old header line is flagged as "old". Old headers are saved on the spool for
 706 debugging but are never sent to any recipients.
 707
 708 Arguments:
 709   h              header line to rewrite
 710   routed_old     if not NULL, this is a rewrite caused by a router, changing
 711                    this domain into routed_new
 712   routed_new     new routed domain if routed_old is not NULL
 713   rewrite_rules  points to chain of rewrite rules
 714   existflags     bits indicating which rewrites exist
 715   replace        if TRUE, the new header is inserted into the header chain
 716                     after the old one, and the old one is marked replaced
 717
 718 Returns:         NULL if header unchanged; otherwise the rewritten header
 719 */
 720
 721 header_line *
 722 rewrite_header(header_line *h, uschar *routed_old, uschar *routed_new,
 723   rewrite_rule *rewrite_rules, int existflags, BOOL replace)
 724 {
 725 switch (h->type)
 726   {
 727   case htype_sender:
 728   return rewrite_one_header(h, rewrite_sender, routed_old, routed_new,
 729     rewrite_rules, existflags, replace);
 730
 731   case htype_from:
 732   return rewrite_one_header(h, rewrite_from, routed_old, routed_new,
 733     rewrite_rules, existflags, replace);
 734
 735   case htype_to:
 736   return rewrite_one_header(h, rewrite_to, routed_old, routed_new,
 737     rewrite_rules, existflags, replace);
 738
 739   case htype_cc:
 740   return rewrite_one_header(h, rewrite_cc, routed_old, routed_new,
 741     rewrite_rules, existflags, replace);
 742
 743   case htype_bcc:
 744   return rewrite_one_header(h, rewrite_bcc, routed_old, routed_new,
 745     rewrite_rules, existflags, replace);
 746
 747   case htype_reply_to:
 748   return rewrite_one_header(h, rewrite_replyto, routed_old, routed_new,
 749     rewrite_rules, existflags, replace);
 750   }
 751
 752 return NULL;
 753 }
 754
 755
 756
 757 /************************************************
 758 *            Test rewriting rules               *
 759 ************************************************/
 760
 761 /* Called from the mainline as a result of the -brw option. Test the
 762 address for all possible cases.
 763
 764 Argument: the address to test
 765 Returns:  nothing
 766 */
 767
 768 void rewrite_test(uschar *s)
 769 {
 770 uschar *recipient, *error;
 771 int i, start, end, domain;
 772 BOOL done_smtp = FALSE;
 773
 774 if (rewrite_existflags == 0)
 775   {
 776   printf("No rewrite rules are defined\n");
 777   return;
 778   }
 779
 780 /* Do SMTP rewrite only if a rule with the S flag exists. Allow <> by
 781 pretending it is a sender. */
 782
 783 if ((rewrite_existflags & rewrite_smtp) != 0)
 784   {
 785   uschar *new = rewrite_one(s, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
 786     US"", global_rewrite_rules);
 787   if (new != s)
 788     {
 789     if (*new == 0)
 790       printf("    SMTP: <>\n");
 791     else
 792       printf("    SMTP: %s\n", new);
 793     done_smtp = TRUE;
 794     }
 795   }
 796
 797 /* Do the other rewrites only if a rule without the S flag exists */
 798
 799 if ((rewrite_existflags & ~rewrite_smtp) == 0) return;
 800
 801 /* Qualify if necessary before extracting the address */
 802
 803 if (parse_find_at(s) == NULL)
 804   s = string_sprintf("%s@%s", s, qualify_domain_recipient);
 805
 806 recipient = parse_extract_address(s, &error, &start, &end, &domain, FALSE);
 807
 808 if (recipient == NULL)
 809   {
 810   if (!done_smtp)
 811     printf("Syntax error in %s\n%c%s\n", s, toupper(error[0]), error+1);
 812   return;
 813   }
 814
 815 for (i = 0; i < 8; i++)
 816   {
 817   BOOL whole = FALSE;
 818   int flag = 1 << i;
 819   uschar *new = rewrite_one(recipient, flag, &whole, FALSE, US"",
 820     global_rewrite_rules);
 821   printf("%s: ", rrname[i]);
 822   if (*new == 0)
 823     printf("<>\n");
 824   else if (whole || (flag & rewrite_all_headers) == 0)
 825     printf("%s\n", CS new);
 826   else printf("%.*s%s%s\n", start, s, new, s+end);
 827   }
 828 }
 829
 830 /* End of rewrite.c */