| 1 | /************************************************* |
| 2 | * Exim - an Internet mail transport agent * |
| 3 | *************************************************/ |
| 4 | |
| 5 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
| 6 | /* See the file NOTICE for conditions of use and distribution. */ |
| 7 | |
| 8 | |
| 9 | #include "exim.h" |
| 10 | |
| 11 | |
| 12 | /************************************************* |
| 13 | * Test a header for matching name * |
| 14 | *************************************************/ |
| 15 | |
| 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 |
| 19 | it just in case. |
| 20 | |
| 21 | Arguments: |
| 22 | h points to the header |
| 23 | name the name to test |
| 24 | len the length of the name |
| 25 | notdel if TRUE, force FALSE for deleted headers |
| 26 | |
| 27 | Returns: TRUE or FALSE |
| 28 | */ |
| 29 | |
| 30 | BOOL |
| 31 | header_testname(header_line *h, const uschar *name, int len, BOOL notdel) |
| 32 | { |
| 33 | uschar *tt; |
| 34 | if (h->type == '*' && notdel) return FALSE; |
| 35 | if (h->text == NULL || strncmpic(h->text, name, len) != 0) return FALSE; |
| 36 | tt = h->text + len; |
| 37 | while (*tt == ' ' || *tt == '\t') tt++; |
| 38 | return *tt == ':'; |
| 39 | } |
| 40 | |
| 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. */ |
| 45 | |
| 46 | BOOL |
| 47 | header_testname_incomplete(header_line *h, const uschar *name, |
| 48 | int len, BOOL notdel) |
| 49 | { |
| 50 | if (h->type == '*' && notdel) return FALSE; |
| 51 | if (h->text == NULL || strncmpic(h->text, name, len) != 0) return FALSE; |
| 52 | return TRUE; |
| 53 | } |
| 54 | |
| 55 | |
| 56 | /************************************************* |
| 57 | * Add new header backend function * |
| 58 | *************************************************/ |
| 59 | |
| 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. |
| 65 | |
| 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. |
| 69 | |
| 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" |
| 72 | flag is not used. |
| 73 | |
| 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 |
| 79 | otherwise. |
| 80 | |
| 81 | Arguments: |
| 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) |
| 86 | format sprintf format |
| 87 | ap va_list value for format arguments |
| 88 | |
| 89 | Returns: nothing |
| 90 | */ |
| 91 | |
| 92 | static void |
| 93 | header_add_backend(BOOL after, uschar *name, BOOL topnot, int type, |
| 94 | const char *format, va_list ap) |
| 95 | { |
| 96 | header_line *h, *new; |
| 97 | header_line **hptr; |
| 98 | |
| 99 | uschar *p, *q; |
| 100 | uschar buffer[HEADER_ADD_BUFFER_SIZE]; |
| 101 | |
| 102 | if (header_last == NULL) return; |
| 103 | |
| 104 | if (!string_vformat(buffer, sizeof(buffer), format, ap)) |
| 105 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "string too long in header_add: " |
| 106 | "%.100s ...", buffer); |
| 107 | |
| 108 | /* Find where to insert this header */ |
| 109 | |
| 110 | if (name == NULL) |
| 111 | { |
| 112 | if (after) |
| 113 | { |
| 114 | hptr = &(header_last->next); |
| 115 | h = NULL; |
| 116 | } |
| 117 | else |
| 118 | { |
| 119 | hptr = &header_list; |
| 120 | |
| 121 | /* header_list->text can be NULL if we get here between when the new |
| 122 | received header is allocated and when it is acutally filled in. We want |
| 123 | that header to be first, so skip it for now. */ |
| 124 | |
| 125 | if (header_list->text == NULL) |
| 126 | hptr = &header_list->next; |
| 127 | h = *hptr; |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | else |
| 132 | { |
| 133 | int len = Ustrlen(name); |
| 134 | |
| 135 | /* Find the first non-deleted header witht the correct name. */ |
| 136 | |
| 137 | for (hptr = &header_list; (h = *hptr) != NULL; hptr = &(h->next)) |
| 138 | { |
| 139 | if (header_testname(h, name, len, TRUE)) break; |
| 140 | } |
| 141 | |
| 142 | /* Handle the case where no header is found. To insert at the bottom, nothing |
| 143 | needs to be done. */ |
| 144 | |
| 145 | if (h == NULL) |
| 146 | { |
| 147 | if (topnot) |
| 148 | { |
| 149 | hptr = &header_list; |
| 150 | h = header_list; |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | /* Handle the case where a header is found. Check for more if "after" is |
| 155 | true. In this case, we want to include deleted headers in the block. */ |
| 156 | |
| 157 | else if (after) |
| 158 | { |
| 159 | for (;;) |
| 160 | { |
| 161 | if (h->next == NULL || !header_testname(h, name, len, FALSE)) break; |
| 162 | hptr = &(h->next); |
| 163 | h = h->next; |
| 164 | } |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | /* Loop for multiple header lines, taking care about continuations. At this |
| 169 | point, we have hptr pointing to the link field that will point to the new |
| 170 | header, and h containing the following header, or NULL. */ |
| 171 | |
| 172 | for (p = q = buffer; *p != 0; ) |
| 173 | { |
| 174 | for (;;) |
| 175 | { |
| 176 | q = Ustrchr(q, '\n'); |
| 177 | if (q == NULL) q = p + Ustrlen(p); |
| 178 | if (*(++q) != ' ' && *q != '\t') break; |
| 179 | } |
| 180 | |
| 181 | new = store_get(sizeof(header_line)); |
| 182 | new->text = string_copyn(p, q - p); |
| 183 | new->slen = q - p; |
| 184 | new->type = type; |
| 185 | new->next = h; |
| 186 | |
| 187 | *hptr = new; |
| 188 | hptr = &(new->next); |
| 189 | |
| 190 | if (h == NULL) header_last = new; |
| 191 | p = q; |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | |
| 196 | /************************************************* |
| 197 | * Add new header anywhere in the chain * |
| 198 | *************************************************/ |
| 199 | |
| 200 | /* This is an external interface to header_add_backend(). |
| 201 | |
| 202 | Arguments: |
| 203 | after TRUE for "after", FALSE for "before" |
| 204 | name name if adding at a specific header, else NULL |
| 205 | topnot TRUE to add at top if no header found |
| 206 | type Exim header type character (htype_something) |
| 207 | format sprintf format |
| 208 | ... format arguments |
| 209 | |
| 210 | Returns: nothing |
| 211 | */ |
| 212 | |
| 213 | void |
| 214 | header_add_at_position(BOOL after, uschar *name, BOOL topnot, int type, |
| 215 | const char *format, ...) |
| 216 | { |
| 217 | va_list ap; |
| 218 | va_start(ap, format); |
| 219 | header_add_backend(after, name, topnot, type, format, ap); |
| 220 | va_end(ap); |
| 221 | } |
| 222 | |
| 223 | |
| 224 | |
| 225 | /************************************************* |
| 226 | * Add new header on end of chain * |
| 227 | *************************************************/ |
| 228 | |
| 229 | /* This is now a convenience interface to header_add_backend(). |
| 230 | |
| 231 | Arguments: |
| 232 | type Exim header type character |
| 233 | format sprintf format |
| 234 | ... arguments for the format |
| 235 | |
| 236 | Returns: nothing |
| 237 | */ |
| 238 | |
| 239 | void |
| 240 | header_add(int type, const char *format, ...) |
| 241 | { |
| 242 | va_list ap; |
| 243 | va_start(ap, format); |
| 244 | header_add_backend(TRUE, NULL, FALSE, type, format, ap); |
| 245 | va_end(ap); |
| 246 | } |
| 247 | |
| 248 | |
| 249 | |
| 250 | /************************************************* |
| 251 | * Remove (mark as old) a header * |
| 252 | *************************************************/ |
| 253 | |
| 254 | /* This function is used by the filter code; it is also exported in the |
| 255 | local_scan() API. If no header is found, the function does nothing. |
| 256 | |
| 257 | Arguments: |
| 258 | occ the occurrence number for multiply-defined headers |
| 259 | <= 0 means "all"; deleted headers are not counted |
| 260 | name the header name |
| 261 | |
| 262 | Returns: nothing |
| 263 | */ |
| 264 | |
| 265 | void |
| 266 | header_remove(int occ, const uschar *name) |
| 267 | { |
| 268 | header_line *h; |
| 269 | int hcount = 0; |
| 270 | int len = Ustrlen(name); |
| 271 | for (h = header_list; h != NULL; h = h->next) |
| 272 | { |
| 273 | if (header_testname(h, name, len, TRUE) && (occ <= 0 || ++hcount == occ)) |
| 274 | { |
| 275 | h->type = htype_old; |
| 276 | if (occ > 0) return; |
| 277 | } |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | |
| 282 | |
| 283 | /************************************************* |
| 284 | * Check the name of a header * |
| 285 | *************************************************/ |
| 286 | |
| 287 | /* This function scans a table of header field names that Exim recognizes, and |
| 288 | returns the identification of a match. If "resent" is true, the header is known |
| 289 | to start with "resent-". In that case, the function matches only those fields |
| 290 | that are allowed to appear with resent- in front of them. |
| 291 | |
| 292 | Arguments: |
| 293 | h points to the header line |
| 294 | is_resent TRUE if the name starts "Resent-" |
| 295 | |
| 296 | Returns: One of the htype_ enum values, identifying the header |
| 297 | */ |
| 298 | |
| 299 | int |
| 300 | header_checkname(header_line *h, BOOL is_resent) |
| 301 | { |
| 302 | uschar *text = h->text; |
| 303 | header_name *bot = header_names; |
| 304 | header_name *top = header_names + header_names_size; |
| 305 | |
| 306 | if (is_resent) text += 7; |
| 307 | |
| 308 | while (bot < top) |
| 309 | { |
| 310 | header_name *mid = bot + (top - bot)/2; |
| 311 | int c = strncmpic(text, mid->name, mid->len); |
| 312 | |
| 313 | if (c == 0) |
| 314 | { |
| 315 | uschar *s = text + mid->len; |
| 316 | while (isspace(*s)) s++; |
| 317 | if (*s == ':') |
| 318 | return (!is_resent || mid->allow_resent)? mid->htype : htype_other; |
| 319 | c = 1; |
| 320 | } |
| 321 | |
| 322 | if (c > 0) bot = mid + 1; else top = mid; |
| 323 | } |
| 324 | |
| 325 | return htype_other; |
| 326 | } |
| 327 | |
| 328 | |
| 329 | /************************************************* |
| 330 | * Scan a header for certain strings * |
| 331 | *************************************************/ |
| 332 | |
| 333 | /* This function is used for the "personal" test. It scans a particular header |
| 334 | line for any one of a number of strings, matched caselessly either as plain |
| 335 | strings, or as regular expressions. If the header line contains a list of |
| 336 | addresses, each match is applied only to the operative part of each address in |
| 337 | the header, and non-regular expressions must be exact matches. |
| 338 | |
| 339 | The patterns can be provided either as a chain of string_item structures, or |
| 340 | inline in the argument list, or both. If there is more than one header of the |
| 341 | same name, they are all searched. |
| 342 | |
| 343 | Arguments: |
| 344 | name header name, including the trailing colon |
| 345 | has_addresses TRUE if the header contains a list of addresses |
| 346 | cond value to return if the header contains any of the strings |
| 347 | strings points to a chain of string_item blocks |
| 348 | count number of inline strings |
| 349 | ... the inline strings |
| 350 | |
| 351 | Returns: cond if the header exists and contains one of the strings; |
| 352 | otherwise !cond |
| 353 | */ |
| 354 | |
| 355 | |
| 356 | /* First we have a local subroutine to handle a single pattern */ |
| 357 | |
| 358 | static BOOL |
| 359 | one_pattern_match(uschar *name, int slen, BOOL has_addresses, uschar *pattern) |
| 360 | { |
| 361 | BOOL yield = FALSE; |
| 362 | header_line *h; |
| 363 | const pcre *re = NULL; |
| 364 | |
| 365 | /* If the pattern is a regex, compile it. Bomb out if compiling fails; these |
| 366 | patterns are all constructed internally and should be valid. */ |
| 367 | |
| 368 | if (*pattern == '^') re = regex_must_compile(pattern, TRUE, FALSE); |
| 369 | |
| 370 | /* Scan for the required header(s) and scan each one */ |
| 371 | |
| 372 | for (h = header_list; !yield && h != NULL; h = h->next) |
| 373 | { |
| 374 | if (h->type == htype_old || slen > h->slen || |
| 375 | strncmpic(name, h->text, slen) != 0) |
| 376 | continue; |
| 377 | |
| 378 | /* If the header is a list of addresses, extract each one in turn, and scan |
| 379 | it. A non-regex scan must be an exact match for the address. */ |
| 380 | |
| 381 | if (has_addresses) |
| 382 | { |
| 383 | uschar *s = h->text + slen; |
| 384 | |
| 385 | while (!yield && *s != 0) |
| 386 | { |
| 387 | uschar *error, *next; |
| 388 | uschar *e = parse_find_address_end(s, FALSE); |
| 389 | int terminator = *e; |
| 390 | int start, end, domain; |
| 391 | |
| 392 | /* Temporarily terminate the string at the address end while extracting |
| 393 | the operative address within. */ |
| 394 | |
| 395 | *e = 0; |
| 396 | next = parse_extract_address(s, &error, &start, &end, &domain, FALSE); |
| 397 | *e = terminator; |
| 398 | |
| 399 | /* Move on, ready for the next address */ |
| 400 | |
| 401 | s = e; |
| 402 | if (*s == ',') s++; |
| 403 | |
| 404 | /* If there is some kind of syntax error, just give up on this header |
| 405 | line. */ |
| 406 | |
| 407 | if (next == NULL) break; |
| 408 | |
| 409 | /* Otherwise, test for the pattern; a non-regex must be an exact match */ |
| 410 | |
| 411 | yield = (re == NULL)? |
| 412 | (strcmpic(next, pattern) == 0) |
| 413 | : |
| 414 | (pcre_exec(re, NULL, CS next, Ustrlen(next), 0, PCRE_EOPT, NULL, 0) |
| 415 | >= 0); |
| 416 | } |
| 417 | } |
| 418 | |
| 419 | /* For headers that are not lists of addresses, scan the entire header line, |
| 420 | and just require "contains" for non-regex patterns. */ |
| 421 | |
| 422 | else |
| 423 | { |
| 424 | yield = (re == NULL)? |
| 425 | (strstric(h->text, pattern, FALSE) != NULL) |
| 426 | : |
| 427 | (pcre_exec(re, NULL, CS h->text, h->slen, 0, PCRE_EOPT, NULL, 0) >= 0); |
| 428 | } |
| 429 | } |
| 430 | |
| 431 | return yield; |
| 432 | } |
| 433 | |
| 434 | |
| 435 | /* The externally visible interface */ |
| 436 | |
| 437 | BOOL |
| 438 | header_match(uschar *name, BOOL has_addresses, BOOL cond, string_item *strings, |
| 439 | int count, ...) |
| 440 | { |
| 441 | va_list ap; |
| 442 | string_item *s; |
| 443 | int i; |
| 444 | int slen = Ustrlen(name); |
| 445 | |
| 446 | for (s = strings; s != NULL; s = s->next) |
| 447 | { |
| 448 | if (one_pattern_match(name, slen, has_addresses, s->text)) return cond; |
| 449 | } |
| 450 | |
| 451 | va_start(ap, count); |
| 452 | for (i = 0; i < count; i++) |
| 453 | { |
| 454 | if (one_pattern_match(name, slen, has_addresses, va_arg(ap, uschar *))) |
| 455 | return cond; |
| 456 | } |
| 457 | va_end(ap); |
| 458 | |
| 459 | return !cond; |
| 460 | } |
| 461 | |
| 462 | /* End of header.c */ |