1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
6 /* See the file NOTICE for conditions of use and distribution. */
12 /*************************************************
13 * Test a header for matching name *
14 *************************************************/
16 /* This function tests the name of a header. It is made into a function because
17 it isn't just a string comparison: spaces and tabs are permitted between the
18 name and the colon. The h->text field should nowadays never be NULL, but check
22 h points to the header
24 len the length of the name
25 notdel if TRUE, force FALSE for deleted headers
27 Returns: TRUE or FALSE
31 header_testname(header_line *h, const uschar *name, int len, BOOL notdel)
34 if (h->type == '*' && notdel) return FALSE;
35 if (h->text == NULL || strncmpic(h->text, name, len) != 0) return FALSE;
37 while (*tt == ' ' || *tt == '\t') tt++;
41 /* This is a copy of the function above, only that it is possible to pass
42 only the beginning of a header name. It simply does a front-anchored
43 substring match. Arguments and Return codes are the same as for
44 header_testname() above. */
47 header_testname_incomplete(header_line *h, const uschar *name,
50 if (h->type == '*' && notdel) return FALSE;
51 if (h->text == NULL || strncmpic(h->text, name, len) != 0) return FALSE;
56 /*************************************************
57 * Add new header backend function *
58 *************************************************/
60 /* The header_last variable points to the last header during message reception
61 and delivery; otherwise it is NULL. We add new headers only when header_last is
62 not NULL. The function may get called sometimes when it is NULL (e.g. during
63 address verification where rewriting options exist). When called from a filter,
64 there may be multiple header lines in a single string.
66 This is an internal static function that is the common back end to the external
67 functions defined below. The general interface allows the header to be inserted
68 before or after a given occurrence of a given header.
70 (a) if "name" is NULL, the header is added at the end of all the existing
71 headers if "after" is true, or at the start if it is false. The "topnot"
74 (b) If "name" is not NULL, the first existing header with that name is sought.
75 If "after" is false, the new header is added before it. If "after" is true,
76 a check is made for adjacent headers with the same name, and the new header
77 is added after the last of them. If a header of the given name is not
78 found, the new header is added first if "topnot" is true, and at the bottom
82 after TRUE for "after", FALSE for "before"
83 name name if adding at a specific header, else NULL
84 topnot TRUE to add at top if no header found
85 type Exim header type character (htype_something)
87 ap va_list value for format arguments
89 Returns: pointer to header struct (last one, if multiple added)
93 header_add_backend(BOOL after, uschar *name, BOOL topnot, int type,
94 const char *format, va_list ap)
96 header_line *h, *new = NULL;
100 uschar buffer[HEADER_ADD_BUFFER_SIZE];
101 gstring gs = { .size = HEADER_ADD_BUFFER_SIZE, .ptr = 0, .s = buffer };
103 if (!header_last) return NULL;
105 if (!string_vformat(&gs, FALSE, format, ap))
106 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "string too long in header_add: "
107 "%.100s ...", string_from_gstring(&gs));
108 string_from_gstring(&gs);
110 /* Find where to insert this header */
115 hptr = &header_last->next;
122 /* header_list->text can be NULL if we get here between when the new
123 received header is allocated and when it is actually filled in. We want
124 that header to be first, so skip it for now. */
126 if (!header_list->text)
127 hptr = &header_list->next;
133 int len = Ustrlen(name);
135 /* Find the first non-deleted header with the correct name. */
137 for (hptr = &header_list; (h = *hptr); hptr = &h->next)
138 if (header_testname(h, name, len, TRUE))
141 /* Handle the case where no header is found. To insert at the bottom, nothing
153 /* Handle the case where a header is found. Check for more if "after" is
154 true. In this case, we want to include deleted headers in the block. */
159 if (!h->next || !header_testname(h, name, len, FALSE)) break;
165 /* Loop for multiple header lines, taking care about continuations. At this
166 point, we have hptr pointing to the link field that will point to the new
167 header, and h containing the following header, or NULL. */
169 for (p = q = buffer; *p; p = q)
173 q = Ustrchr(q, '\n');
174 if (!q) q = p + Ustrlen(p);
175 if (*(++q) != ' ' && *q != '\t') break;
178 new = store_get(sizeof(header_line));
179 new->text = string_copyn(p, q - p);
187 if (!h) header_last = new;
193 /*************************************************
194 * Add new header anywhere in the chain *
195 *************************************************/
197 /* This is an external interface to header_add_backend().
200 after TRUE for "after", FALSE for "before"
201 name name if adding at a specific header, else NULL
202 topnot TRUE to add at top if no header found
203 type Exim header type character (htype_something)
204 format sprintf format
207 Returns: pointer to header struct added
211 header_add_at_position_internal(BOOL after, uschar *name, BOOL topnot, int type,
212 const char *format, ...)
216 va_start(ap, format);
217 h = header_add_backend(after, name, topnot, type, format, ap);
223 /* Documented external i/f for local_scan */
225 header_add_at_position(BOOL after, uschar *name, BOOL topnot, int type,
226 const char *format, ...)
229 va_start(ap, format);
230 (void) header_add_backend(after, name, topnot, type, format, ap);
234 /*************************************************
235 * Add new header on end of chain *
236 *************************************************/
238 /* This is now a convenience interface to header_add_backend().
241 type Exim header type character
242 format sprintf format
243 ... arguments for the format
249 header_add(int type, const char *format, ...)
252 va_start(ap, format);
253 (void) header_add_backend(TRUE, NULL, FALSE, type, format, ap);
259 /*************************************************
260 * Remove (mark as old) a header *
261 *************************************************/
263 /* This function is used by the filter code; it is also exported in the
264 local_scan() API. If no header is found, the function does nothing.
267 occ the occurrence number for multiply-defined headers
268 <= 0 means "all"; deleted headers are not counted
275 header_remove(int occ, const uschar *name)
278 int len = Ustrlen(name);
279 for (header_line * h = header_list; h; h = h->next)
280 if (header_testname(h, name, len, TRUE) && (occ <= 0 || ++hcount == occ))
289 /*************************************************
290 * Check the name of a header *
291 *************************************************/
293 /* This function scans a table of header field names that Exim recognizes, and
294 returns the identification of a match. If "resent" is true, the header is known
295 to start with "resent-". In that case, the function matches only those fields
296 that are allowed to appear with resent- in front of them.
299 h points to the header line
300 is_resent TRUE if the name starts "Resent-"
302 Returns: One of the htype_ enum values, identifying the header
306 header_checkname(header_line *h, BOOL is_resent)
308 uschar *text = h->text;
309 header_name *bot = header_names;
310 header_name *top = header_names + header_names_size;
312 if (is_resent) text += 7;
316 header_name *mid = bot + (top - bot)/2;
317 int c = strncmpic(text, mid->name, mid->len);
321 uschar *s = text + mid->len;
322 while (isspace(*s)) s++;
324 return (!is_resent || mid->allow_resent)? mid->htype : htype_other;
328 if (c > 0) bot = mid + 1; else top = mid;
335 /*************************************************
336 * Scan a header for certain strings *
337 *************************************************/
339 /* This function is used for the "personal" test. It scans a particular header
340 line for any one of a number of strings, matched caselessly either as plain
341 strings, or as regular expressions. If the header line contains a list of
342 addresses, each match is applied only to the operative part of each address in
343 the header, and non-regular expressions must be exact matches.
345 The patterns can be provided either as a chain of string_item structures, or
346 inline in the argument list, or both. If there is more than one header of the
347 same name, they are all searched.
350 name header name, including the trailing colon
351 has_addresses TRUE if the header contains a list of addresses
352 cond value to return if the header contains any of the strings
353 strings points to a chain of string_item blocks
354 count number of inline strings
355 ... the inline strings
357 Returns: cond if the header exists and contains one of the strings;
362 /* First we have a local subroutine to handle a single pattern */
365 one_pattern_match(uschar *name, int slen, BOOL has_addresses, uschar *pattern)
368 const pcre *re = NULL;
370 /* If the pattern is a regex, compile it. Bomb out if compiling fails; these
371 patterns are all constructed internally and should be valid. */
373 if (*pattern == '^') re = regex_must_compile(pattern, TRUE, FALSE);
375 /* Scan for the required header(s) and scan each one */
377 for (header_line * h = header_list; !yield && h; h = h->next)
379 if (h->type == htype_old || slen > h->slen ||
380 strncmpic(name, h->text, slen) != 0)
383 /* If the header is a list of addresses, extract each one in turn, and scan
384 it. A non-regex scan must be an exact match for the address. */
388 uschar *s = h->text + slen;
392 uschar *error, *next;
393 uschar *e = parse_find_address_end(s, FALSE);
395 int start, end, domain;
397 /* Temporarily terminate the string at the address end while extracting
398 the operative address within. */
401 next = parse_extract_address(s, &error, &start, &end, &domain, FALSE);
404 /* Move on, ready for the next address */
409 /* If there is some kind of syntax error, just give up on this header
412 if (next == NULL) break;
414 /* Otherwise, test for the pattern; a non-regex must be an exact match */
416 yield = (re == NULL)?
417 (strcmpic(next, pattern) == 0)
419 (pcre_exec(re, NULL, CS next, Ustrlen(next), 0, PCRE_EOPT, NULL, 0)
424 /* For headers that are not lists of addresses, scan the entire header line,
425 and just require "contains" for non-regex patterns. */
429 yield = (re == NULL)?
430 (strstric(h->text, pattern, FALSE) != NULL)
432 (pcre_exec(re, NULL, CS h->text, h->slen, 0, PCRE_EOPT, NULL, 0) >= 0);
440 /* The externally visible interface */
443 header_match(uschar *name, BOOL has_addresses, BOOL cond, string_item *strings,
447 int slen = Ustrlen(name);
449 for (string_item * s = strings; s; s = s->next)
450 if (one_pattern_match(name, slen, has_addresses, s->text))
454 for (int i = 0; i < count; i++)
455 if (one_pattern_match(name, slen, has_addresses, va_arg(ap, uschar *)))
465 /* End of header.c */