Commit | Line | Data |
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0756eb3c PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
5 | /* | |
6 | * Exim - CDB database lookup module | |
7 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
8 | * | |
9 | * Copyright (c) 1998 Nigel Metheringham, Planet Online Ltd | |
1e1ddfac | 10 | * Copyright (c) The Exim Maintainers 2020 |
0756eb3c PH |
11 | * |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version 2 | |
15 | * of the License, or (at your option) any later version. | |
16 | * | |
17 | * -------------------------------------------------------------- | |
18 | * Modified by PH for Exim 4: | |
19 | * Changed over to using unsigned chars | |
20 | * Makes use of lf_check_file() for file checking | |
21 | * -------------------------------------------------------------- | |
3386088d PP |
22 | * Modified by The Exim Maintainers 2015: |
23 | * const propagation | |
24 | * -------------------------------------------------------------- | |
0756eb3c PH |
25 | * |
26 | * This program is distributed in the hope that it will be useful, | |
27 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
28 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
29 | * GNU General Public License for more details. | |
30 | * | |
31 | * You should have received a copy of the GNU General Public License | |
32 | * along with this program; if not, write to the Free Software | |
33 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA | |
34 | * 02111-1307, USA. | |
35 | * | |
36 | * | |
37 | * This code implements Dan Bernstein's Constant DataBase (cdb) spec. | |
38 | * Information, the spec and sample code for cdb can be obtained from | |
39 | * http://www.pobox.com/~djb/cdb.html | |
40 | * | |
41 | * This implementation borrows some code from Dan Bernstein's | |
42 | * implementation (which has no license restrictions applied to it). | |
43 | * This (read-only) implementation is completely contained within | |
44 | * cdb.[ch] it does *not* link against an external cdb library. | |
45 | * | |
46 | * | |
4c04137d | 47 | * There are 2 variants included within this code. One uses MMAP and |
0756eb3c PH |
48 | * should give better performance especially for multiple lookups on a |
49 | * modern machine. The other is the default implementation which is | |
50 | * used in the case where the MMAP fails or if MMAP was not compiled | |
51 | * in. this implementation is the same as the original reference cdb | |
52 | * implementation. The MMAP version is compiled in if the HAVE_MMAP | |
53 | * preprocessor define is defined - this should be set in the system | |
54 | * specific os.h file. | |
55 | * | |
56 | */ | |
57 | ||
58 | ||
59 | #include "../exim.h" | |
60 | #include "lf_functions.h" | |
0756eb3c PH |
61 | |
62 | #ifdef HAVE_MMAP | |
63 | # include <sys/mman.h> | |
64 | /* Not all implementations declare MAP_FAILED */ | |
65 | # ifndef MAP_FAILED | |
66 | # define MAP_FAILED ((void *) -1) | |
67 | # endif /* MAP_FAILED */ | |
68 | #endif /* HAVE_MMAP */ | |
69 | ||
70 | ||
71 | #define CDB_HASH_SPLIT 256 /* num pieces the hash table is split into */ | |
72 | #define CDB_HASH_MASK 255 /* mask to and off split value */ | |
73 | #define CDB_HASH_ENTRY 8 /* how big each offset it */ | |
74 | #define CDB_HASH_TABLE (CDB_HASH_SPLIT * CDB_HASH_ENTRY) | |
75 | ||
76 | /* State information for cdb databases that are open NB while the db | |
77 | * is open its contents will not change (cdb dbs are normally updated | |
78 | * atomically by renaming). However the lifetime of one of these | |
79 | * state structures should be limited - ie a long running daemon | |
80 | * that opens one may hit problems.... | |
81 | */ | |
82 | ||
83 | struct cdb_state { | |
84 | int fileno; | |
85 | off_t filelen; | |
86 | uschar *cdb_map; | |
87 | uschar *cdb_offsets; | |
88 | }; | |
89 | ||
90 | /* 32 bit unsigned type - this is an int on all modern machines */ | |
91 | typedef unsigned int uint32; | |
92 | ||
93 | /* | |
94 | * cdb_hash() | |
95 | * Internal function to make hash value */ | |
96 | ||
97 | static uint32 | |
576bd90c | 98 | cdb_hash(const uschar *buf, unsigned int len) |
0756eb3c PH |
99 | { |
100 | uint32 h; | |
101 | ||
102 | h = 5381; | |
103 | while (len) { | |
104 | --len; | |
105 | h += (h << 5); | |
106 | h ^= (uint32) *buf++; | |
107 | } | |
108 | return h; | |
109 | } | |
110 | ||
111 | /* | |
112 | * cdb_bread() | |
113 | * Internal function to read len bytes from disk, coping with oddities */ | |
114 | ||
115 | static int | |
116 | cdb_bread(int fd, | |
117 | uschar *buf, | |
118 | int len) | |
119 | { | |
120 | int r; | |
121 | while (len > 0) { | |
122 | do | |
123 | r = Uread(fd,buf,len); | |
124 | while ((r == -1) && (errno == EINTR)); | |
125 | if (r == -1) return -1; | |
126 | if (r == 0) { errno = EIO; return -1; } | |
127 | buf += r; | |
128 | len -= r; | |
129 | } | |
130 | return 0; | |
131 | } | |
132 | ||
133 | /* | |
134 | * cdb_bread() | |
4c04137d | 135 | * Internal function to parse 4 byte number (endian independent) */ |
0756eb3c PH |
136 | |
137 | static uint32 | |
138 | cdb_unpack(uschar *buf) | |
139 | { | |
d447dbd1 JH |
140 | uint32 num; |
141 | num = buf[3]; num <<= 8; | |
142 | num += buf[2]; num <<= 8; | |
143 | num += buf[1]; num <<= 8; | |
144 | num += buf[0]; | |
145 | return num; | |
0756eb3c PH |
146 | } |
147 | ||
e6d225ae DW |
148 | static void cdb_close(void *handle); |
149 | ||
150 | static void * | |
d447dbd1 | 151 | cdb_open(const uschar * filename, uschar ** errmsg) |
0756eb3c | 152 | { |
d447dbd1 JH |
153 | int fileno; |
154 | struct cdb_state *cdbp; | |
155 | struct stat statbuf; | |
156 | void * mapbuf; | |
157 | ||
158 | if ((fileno = Uopen(filename, O_RDONLY, 0)) < 0) | |
159 | { | |
160 | int save_errno = errno; | |
161 | *errmsg = string_open_failed(errno, "%s for cdb lookup", filename); | |
162 | errno = save_errno; | |
163 | return NULL; | |
0756eb3c PH |
164 | } |
165 | ||
d447dbd1 JH |
166 | if (fstat(fileno, &statbuf) != 0) |
167 | { | |
168 | int save_errno = errno; | |
169 | *errmsg = string_open_failed(errno, | |
170 | "fstat(%s) failed - cannot do cdb lookup", | |
171 | filename); | |
172 | errno = save_errno; | |
173 | return NULL; | |
0756eb3c PH |
174 | } |
175 | ||
d447dbd1 JH |
176 | /* If this is a valid file, then it *must* be at least |
177 | CDB_HASH_TABLE bytes long */ | |
0756eb3c | 178 | |
d447dbd1 JH |
179 | if (statbuf.st_size < CDB_HASH_TABLE) |
180 | { | |
181 | int save_errno = errno; | |
182 | *errmsg = string_open_failed(errno, | |
183 | "%s too short for cdb lookup", | |
184 | filename); | |
185 | errno = save_errno; | |
186 | return NULL; | |
187 | } | |
188 | ||
189 | /* Having got a file open we need the structure to put things in */ | |
190 | cdbp = store_get(sizeof(struct cdb_state), FALSE); | |
191 | /* store_get() does not return if memory was not available... */ | |
192 | /* preload the structure.... */ | |
193 | cdbp->fileno = fileno; | |
194 | cdbp->filelen = statbuf.st_size; | |
195 | cdbp->cdb_map = NULL; | |
196 | cdbp->cdb_offsets = NULL; | |
197 | ||
198 | /* if we are allowed to we use mmap here.... */ | |
0756eb3c | 199 | #ifdef HAVE_MMAP |
d447dbd1 JH |
200 | if ((mapbuf = mmap(NULL, statbuf.st_size, PROT_READ, MAP_SHARED, fileno, 0)) |
201 | != MAP_FAILED) | |
202 | { | |
203 | /* We have an mmap-ed section. Now we can just use it */ | |
204 | cdbp->cdb_map = mapbuf; | |
205 | /* The offsets can be set to the same value since they should | |
206 | * effectively be cached as well | |
207 | */ | |
208 | cdbp->cdb_offsets = mapbuf; | |
209 | ||
210 | /* Now return the state struct */ | |
211 | return(cdbp); | |
212 | } | |
213 | ||
214 | /* If we got here the map failed. Basically we can ignore this since we fall | |
215 | back to slower methods.... However lets debug log it... */ | |
216 | ||
217 | DEBUG(D_lookup) debug_printf_indent("cdb mmap failed - %d\n", errno); | |
0756eb3c PH |
218 | #endif /* HAVE_MMAP */ |
219 | ||
d447dbd1 JH |
220 | /* In this case we have either not got MMAP allowed, or it failed */ |
221 | ||
222 | /* get a buffer to stash the basic offsets in - this should speed | |
223 | things up a lot - especially on multiple lookups */ | |
224 | ||
225 | cdbp->cdb_offsets = store_get(CDB_HASH_TABLE, FALSE); | |
226 | ||
227 | /* now fill the buffer up... */ | |
228 | ||
229 | if (cdb_bread(fileno, cdbp->cdb_offsets, CDB_HASH_TABLE) == -1) | |
230 | { | |
231 | /* read of hash table failed, oh dear, oh..... time to give up I think.... | |
232 | call the close routine (deallocs the memory), and return NULL */ | |
233 | ||
234 | *errmsg = string_open_failed(errno, | |
235 | "cannot read header from %s for cdb lookup", | |
236 | filename); | |
237 | cdb_close(cdbp); | |
238 | return NULL; | |
0756eb3c PH |
239 | } |
240 | ||
d447dbd1 JH |
241 | /* Everything else done - return the cache structure */ |
242 | return cdbp; | |
0756eb3c PH |
243 | } |
244 | ||
245 | ||
246 | ||
247 | /************************************************* | |
248 | * Check entry point * | |
249 | *************************************************/ | |
250 | ||
e6d225ae | 251 | static BOOL |
d447dbd1 JH |
252 | cdb_check(void * handle, const uschar * filename, int modemask, |
253 | uid_t * owners, gid_t * owngroups, uschar ** errmsg) | |
0756eb3c | 254 | { |
d447dbd1 JH |
255 | struct cdb_state * cdbp = handle; |
256 | return lf_check_file(cdbp->fileno, filename, S_IFREG, modemask, | |
257 | owners, owngroups, "cdb", errmsg) == 0; | |
0756eb3c PH |
258 | } |
259 | ||
260 | ||
261 | ||
262 | /************************************************* | |
263 | * Find entry point * | |
264 | *************************************************/ | |
265 | ||
e6d225ae | 266 | static int |
d447dbd1 | 267 | cdb_find(void * handle, const uschar * filename, const uschar * keystring, |
67a57a5a JH |
268 | int key_len, uschar ** result, uschar ** errmsg, uint * do_cache, |
269 | const uschar * opts) | |
0756eb3c | 270 | { |
d88f0784 JH |
271 | struct cdb_state * cdbp = handle; |
272 | uint32 item_key_len, | |
273 | item_dat_len, | |
274 | key_hash, | |
275 | item_hash, | |
276 | item_posn, | |
277 | cur_offset, | |
278 | end_offset, | |
279 | hash_offset_entry, | |
280 | hash_offset, | |
281 | hash_offlen, | |
282 | hash_slotnm; | |
d88f0784 JH |
283 | |
284 | /* Keep picky compilers happy */ | |
285 | do_cache = do_cache; | |
286 | ||
287 | key_hash = cdb_hash(keystring, key_len); | |
288 | ||
289 | hash_offset_entry = CDB_HASH_ENTRY * (key_hash & CDB_HASH_MASK); | |
290 | hash_offset = cdb_unpack(cdbp->cdb_offsets + hash_offset_entry); | |
291 | hash_offlen = cdb_unpack(cdbp->cdb_offsets + hash_offset_entry + 4); | |
292 | ||
293 | /* If the offset length is zero this key cannot be in the file */ | |
294 | ||
295 | if (hash_offlen == 0) | |
296 | return FAIL; | |
297 | ||
298 | hash_slotnm = (key_hash >> 8) % hash_offlen; | |
299 | ||
300 | /* check to ensure that the file is not corrupt | |
301 | * if the hash_offset + (hash_offlen * CDB_HASH_ENTRY) is longer | |
302 | * than the file, then we have problems.... */ | |
303 | ||
304 | if ((hash_offset + (hash_offlen * CDB_HASH_ENTRY)) > cdbp->filelen) | |
305 | { | |
306 | *errmsg = string_sprintf("cdb: corrupt cdb file %s (too short)", | |
307 | filename); | |
42c7f0b4 | 308 | DEBUG(D_lookup) debug_printf_indent("%s\n", *errmsg); |
d88f0784 | 309 | return DEFER; |
0756eb3c PH |
310 | } |
311 | ||
d88f0784 JH |
312 | cur_offset = hash_offset + (hash_slotnm * CDB_HASH_ENTRY); |
313 | end_offset = hash_offset + (hash_offlen * CDB_HASH_ENTRY); | |
314 | ||
315 | /* if we are allowed to we use mmap here.... */ | |
316 | ||
0756eb3c | 317 | #ifdef HAVE_MMAP |
d88f0784 JH |
318 | /* make sure the mmap was OK */ |
319 | if (cdbp->cdb_map != NULL) | |
320 | { | |
321 | uschar * cur_pos = cur_offset + cdbp->cdb_map; | |
322 | uschar * end_pos = end_offset + cdbp->cdb_map; | |
323 | ||
d7978c0f | 324 | for (int loop = 0; (loop < hash_offlen); ++loop) |
d88f0784 JH |
325 | { |
326 | item_hash = cdb_unpack(cur_pos); | |
327 | cur_pos += 4; | |
328 | item_posn = cdb_unpack(cur_pos); | |
329 | cur_pos += 4; | |
330 | ||
0756eb3c | 331 | /* if the position is zero then we have a definite miss */ |
d88f0784 | 332 | |
0756eb3c PH |
333 | if (item_posn == 0) |
334 | return FAIL; | |
335 | ||
d88f0784 JH |
336 | if (item_hash == key_hash) |
337 | { /* matching hash value */ | |
338 | uschar * item_ptr = cdbp->cdb_map + item_posn; | |
339 | ||
340 | item_key_len = cdb_unpack(item_ptr); | |
341 | item_ptr += 4; | |
342 | item_dat_len = cdb_unpack(item_ptr); | |
343 | item_ptr += 4; | |
344 | ||
0756eb3c | 345 | /* check key length matches */ |
d88f0784 JH |
346 | |
347 | if (item_key_len == key_len) | |
348 | { | |
349 | /* finally check if key matches */ | |
350 | if (Ustrncmp(keystring, item_ptr, key_len) == 0) | |
351 | { | |
352 | /* we have a match.... * make item_ptr point to data */ | |
353 | ||
354 | item_ptr += item_key_len; | |
355 | ||
f3ebb786 JH |
356 | /* ... and the returned result. Assume it is not |
357 | tainted, lacking any way of telling. */ | |
d88f0784 | 358 | |
f3ebb786 | 359 | *result = store_get(item_dat_len + 1, FALSE); |
d88f0784 JH |
360 | memcpy(*result, item_ptr, item_dat_len); |
361 | (*result)[item_dat_len] = 0; | |
362 | return OK; | |
363 | } | |
364 | } | |
365 | } | |
366 | /* handle warp round of table */ | |
367 | if (cur_pos == end_pos) | |
368 | cur_pos = cdbp->cdb_map + hash_offset; | |
369 | } | |
370 | /* looks like we failed... */ | |
371 | return FAIL; | |
372 | } | |
373 | ||
374 | #endif /* HAVE_MMAP */ | |
375 | ||
d7978c0f | 376 | for (int loop = 0; (loop < hash_offlen); ++loop) |
d88f0784 JH |
377 | { |
378 | uschar packbuf[8]; | |
379 | ||
d315eda1 JH |
380 | if (lseek(cdbp->fileno, (off_t) cur_offset, SEEK_SET) == -1) return DEFER; |
381 | if (cdb_bread(cdbp->fileno, packbuf, 8) == -1) return DEFER; | |
d88f0784 JH |
382 | |
383 | item_hash = cdb_unpack(packbuf); | |
384 | item_posn = cdb_unpack(packbuf + 4); | |
385 | ||
386 | /* if the position is zero then we have a definite miss */ | |
387 | ||
388 | if (item_posn == 0) | |
389 | return FAIL; | |
390 | ||
391 | if (item_hash == key_hash) | |
392 | { /* matching hash value */ | |
393 | if (lseek(cdbp->fileno, (off_t) item_posn, SEEK_SET) == -1) return DEFER; | |
394 | if (cdb_bread(cdbp->fileno, packbuf, 8) == -1) return DEFER; | |
395 | ||
396 | item_key_len = cdb_unpack(packbuf); | |
397 | ||
398 | /* check key length matches */ | |
399 | ||
400 | if (item_key_len == key_len) | |
401 | { /* finally check if key matches */ | |
f3ebb786 JH |
402 | rmark reset_point = store_mark(); |
403 | uschar * item_key = store_get(key_len, TRUE); /* keys liable to be tainted */ | |
d88f0784 JH |
404 | |
405 | if (cdb_bread(cdbp->fileno, item_key, key_len) == -1) return DEFER; | |
f3ebb786 JH |
406 | if (Ustrncmp(keystring, item_key, key_len) == 0) |
407 | { | |
408 | /* Reclaim some store */ | |
409 | store_reset(reset_point); | |
410 | ||
411 | /* matches - get data length */ | |
412 | item_dat_len = cdb_unpack(packbuf + 4); | |
413 | ||
414 | /* then we build a new result string. We know we have enough | |
415 | memory so disable Coverity errors about the tainted item_dat_ken */ | |
416 | ||
417 | *result = store_get(item_dat_len + 1, FALSE); | |
418 | /* coverity[tainted_data] */ | |
419 | if (cdb_bread(cdbp->fileno, *result, item_dat_len) == -1) | |
420 | return DEFER; | |
421 | ||
422 | /* coverity[tainted_data] */ | |
423 | (*result)[item_dat_len] = 0; | |
424 | return OK; | |
425 | } | |
d88f0784 | 426 | /* Reclaim some store */ |
f3ebb786 | 427 | store_reset(reset_point); |
0756eb3c PH |
428 | } |
429 | } | |
d88f0784 | 430 | cur_offset += 8; |
0756eb3c | 431 | |
d88f0784 JH |
432 | /* handle warp round of table */ |
433 | if (cur_offset == end_offset) | |
434 | cur_offset = hash_offset; | |
0756eb3c | 435 | } |
d88f0784 | 436 | return FAIL; |
0756eb3c PH |
437 | } |
438 | ||
439 | ||
440 | ||
441 | /************************************************* | |
442 | * Close entry point * | |
443 | *************************************************/ | |
444 | ||
445 | /* See local README for interface description */ | |
446 | ||
e6d225ae | 447 | static void |
0756eb3c PH |
448 | cdb_close(void *handle) |
449 | { | |
450 | struct cdb_state * cdbp = handle; | |
451 | ||
452 | #ifdef HAVE_MMAP | |
d7978c0f JH |
453 | if (cdbp->cdb_map) |
454 | { | |
455 | munmap(CS cdbp->cdb_map, cdbp->filelen); | |
456 | if (cdbp->cdb_map == cdbp->cdb_offsets) | |
0756eb3c | 457 | cdbp->cdb_offsets = NULL; |
d7978c0f | 458 | } |
0756eb3c PH |
459 | #endif /* HAVE_MMAP */ |
460 | ||
d7978c0f | 461 | (void)close(cdbp->fileno); |
0756eb3c PH |
462 | } |
463 | ||
6545de78 PP |
464 | |
465 | ||
466 | /************************************************* | |
467 | * Version reporting entry point * | |
468 | *************************************************/ | |
469 | ||
470 | /* See local README for interface description. */ | |
471 | ||
472 | #include "../version.h" | |
473 | ||
474 | void | |
475 | cdb_version_report(FILE *f) | |
476 | { | |
477 | #ifdef DYNLOOKUP | |
478 | fprintf(f, "Library version: CDB: Exim version %s\n", EXIM_VERSION_STR); | |
479 | #endif | |
480 | } | |
481 | ||
482 | ||
e6d225ae | 483 | lookup_info cdb_lookup_info = { |
9f400174 JH |
484 | .name = US"cdb", /* lookup name */ |
485 | .type = lookup_absfile, /* absolute file name */ | |
486 | .open = cdb_open, /* open function */ | |
487 | .check = cdb_check, /* check function */ | |
488 | .find = cdb_find, /* find function */ | |
489 | .close = cdb_close, /* close function */ | |
490 | .tidy = NULL, /* no tidy function */ | |
491 | .quote = NULL, /* no quoting function */ | |
492 | .version_report = cdb_version_report /* version reporting */ | |
e6d225ae DW |
493 | }; |
494 | ||
495 | #ifdef DYNLOOKUP | |
496 | #define cdb_lookup_module_info _lookup_module_info | |
497 | #endif | |
498 | ||
499 | static lookup_info *_lookup_list[] = { &cdb_lookup_info }; | |
500 | lookup_module_info cdb_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 }; | |
501 | ||
0756eb3c | 502 | /* End of lookups/cdb.c */ |