Fix buffer overrun in spam= acl condition. Bug 1552
[exim.git] / src / src / spam.c
CommitLineData
8523533c
TK
1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
5/* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2003-???? */
6/* License: GPL */
7
8/* Code for calling spamassassin's spamd. Called from acl.c. */
9
10#include "exim.h"
11#ifdef WITH_CONTENT_SCAN
12#include "spam.h"
13
14uschar spam_score_buffer[16];
15uschar spam_score_int_buffer[16];
16uschar spam_bar_buffer[128];
17uschar spam_report_buffer[32600];
18uschar prev_user_name[128] = "";
19int spam_ok = 0;
20int spam_rc = 0;
f7274286 21uschar *prev_spamd_address_work = NULL;
8523533c 22
c007c974
JH
23int
24spam(uschar **listptr)
25{
8523533c
TK
26 int sep = 0;
27 uschar *list = *listptr;
28 uschar *user_name;
29 uschar user_name_buffer[128];
f7b63901 30 unsigned long mbox_size;
8523533c 31 FILE *mbox_file;
0f501486 32 int spamd_sock = -1;
8523533c 33 uschar spamd_buffer[32600];
cfe75fc3 34 int i, j, offset, result;
8523533c
TK
35 uschar spamd_version[8];
36 uschar spamd_score_char;
37 double spamd_threshold, spamd_score;
38 int spamd_report_offset;
39 uschar *p,*q;
40 int override = 0;
cfe75fc3
PH
41 time_t start;
42 size_t read, wrote;
8523533c 43 struct sockaddr_un server;
f452e07e 44#ifndef NO_POLL_H
cfe75fc3 45 struct pollfd pollfd;
25257489
PH
46#else /* Patch posted by Erik ? for OS X */
47 struct timeval select_tv; /* and applied by PH */
48 fd_set select_fd;
f452e07e 49#endif
b6e6e716 50 uschar *spamd_address_work;
8523533c 51
5614ee86 52 /* stop compiler warning */
91ecef39 53 result = 0;
5614ee86 54
8523533c
TK
55 /* find the username from the option list */
56 if ((user_name = string_nextinlist(&list, &sep,
57 user_name_buffer,
58 sizeof(user_name_buffer))) == NULL) {
59 /* no username given, this means no scanning should be done */
60 return FAIL;
61 };
62
63 /* if username is "0" or "false", do not scan */
64 if ( (Ustrcmp(user_name,"0") == 0) ||
65 (strcmpic(user_name,US"false") == 0) ) {
66 return FAIL;
67 };
68
69 /* if there is an additional option, check if it is "true" */
70 if (strcmpic(list,US"true") == 0) {
71 /* in that case, always return true later */
72 override = 1;
73 };
74
f7274286
PP
75 /* expand spamd_address if needed */
76 if (*spamd_address == '$') {
77 spamd_address_work = expand_string(spamd_address);
78 if (spamd_address_work == NULL) {
79 log_write(0, LOG_MAIN|LOG_PANIC,
80 "spamassassin acl condition: spamd_address starts with $, but expansion failed: %s", expand_string_message);
81 return DEFER;
82 }
83 }
84 else
85 spamd_address_work = spamd_address;
86
87 /* check if previous spamd_address was expanded and has changed. dump cached results if so */
88 if ( spam_ok && ( prev_spamd_address_work != NULL) && (Ustrcmp(prev_spamd_address_work, spamd_address_work) != 0)) {
89 spam_ok = 0;
90 }
91
8e669ac1 92 /* if we scanned for this username last time, just return */
8523533c
TK
93 if ( spam_ok && ( Ustrcmp(prev_user_name, user_name) == 0 ) ) {
94 if (override)
95 return OK;
96 else
97 return spam_rc;
98 };
8e669ac1 99
8523533c 100 /* make sure the eml mbox file is spooled up */
8544e77a 101 mbox_file = spool_mbox(&mbox_size, NULL);
8e669ac1 102
8523533c
TK
103 if (mbox_file == NULL) {
104 /* error while spooling */
105 log_write(0, LOG_MAIN|LOG_PANIC,
106 "spam acl condition: error while creating mbox spool file");
107 return DEFER;
108 };
109
cfe75fc3 110 start = time(NULL);
b6e6e716 111
8523533c 112 /* socket does not start with '/' -> network socket */
b6e6e716 113 if (*spamd_address_work != '/') {
8523533c 114 int num_servers = 0;
29cfeb94 115 int current_server;
8523533c 116 uschar *address = NULL;
e1e7cfcb 117 uschar *spamd_address_list_ptr = spamd_address_work;
8523533c
TK
118 uschar address_buffer[256];
119 spamd_address_container * spamd_address_vector[32];
120
121 /* Check how many spamd servers we have
122 and register their addresses */
123 while ((address = string_nextinlist(&spamd_address_list_ptr, &sep,
124 address_buffer,
125 sizeof(address_buffer))) != NULL) {
8e669ac1 126
29cfeb94 127 /* Potential memory leak as we never free the store. */
8523533c
TK
128 spamd_address_container *this_spamd =
129 (spamd_address_container *)store_get(sizeof(spamd_address_container));
8e669ac1 130
8523533c 131 /* grok spamd address and port */
e252eb8c
JH
132 if (sscanf(CS address, "%23s %u", this_spamd->tcp_addr, &(this_spamd->tcp_port)) != 2)
133 {
8523533c
TK
134 log_write(0, LOG_MAIN,
135 "spam acl condition: warning - invalid spamd address: '%s'", address);
136 continue;
137 };
8e669ac1 138
8523533c
TK
139 spamd_address_vector[num_servers] = this_spamd;
140 num_servers++;
141 if (num_servers > 31)
142 break;
143 };
8e669ac1 144
8523533c
TK
145 /* check if we have at least one server */
146 if (!num_servers) {
147 log_write(0, LOG_MAIN|LOG_PANIC,
148 "spam acl condition: no useable spamd server addresses in spamd_address configuration option.");
f1e894f3 149 (void)fclose(mbox_file);
8523533c
TK
150 return DEFER;
151 };
152
29cfeb94 153 while ( num_servers > 0 ) {
2e64baa9 154 int i;
8523533c 155
29cfeb94
PP
156 /* Randomly pick a server to try */
157 current_server = random_number( num_servers );
8e669ac1 158
8523533c
TK
159 debug_printf("trying server %s, port %u\n",
160 spamd_address_vector[current_server]->tcp_addr,
161 spamd_address_vector[current_server]->tcp_port);
8e669ac1 162
8523533c
TK
163 /* contact a spamd */
164 if ( (spamd_sock = ip_socket(SOCK_STREAM, AF_INET)) < 0) {
165 log_write(0, LOG_MAIN|LOG_PANIC,
166 "spam acl condition: error creating IP socket for spamd");
f1e894f3 167 (void)fclose(mbox_file);
8e669ac1 168 return DEFER;
8523533c 169 };
8e669ac1 170
8523533c
TK
171 if (ip_connect( spamd_sock,
172 AF_INET,
173 spamd_address_vector[current_server]->tcp_addr,
174 spamd_address_vector[current_server]->tcp_port,
175 5 ) > -1) {
176 /* connection OK */
177 break;
178 };
8e669ac1 179
8523533c
TK
180 log_write(0, LOG_MAIN|LOG_PANIC,
181 "spam acl condition: warning - spamd connection to %s, port %u failed: %s",
182 spamd_address_vector[current_server]->tcp_addr,
183 spamd_address_vector[current_server]->tcp_port,
184 strerror(errno));
29cfeb94
PP
185
186 (void)close(spamd_sock);
187
188 /* Remove the server from the list. XXX We should free the memory */
189 num_servers--;
29cfeb94
PP
190 for( i = current_server; i < num_servers; i++ )
191 spamd_address_vector[i] = spamd_address_vector[i+1];
192 }
193
194 if ( num_servers == 0 ) {
195 log_write(0, LOG_MAIN|LOG_PANIC, "spam acl condition: all spamd servers failed");
196 (void)fclose(mbox_file);
197 return DEFER;
198 }
8523533c
TK
199
200 }
201 else {
202 /* open the local socket */
203
204 if ((spamd_sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
205 log_write(0, LOG_MAIN|LOG_PANIC,
206 "malware acl condition: spamd: unable to acquire socket (%s)",
207 strerror(errno));
f1e894f3 208 (void)fclose(mbox_file);
8523533c
TK
209 return DEFER;
210 }
211
212 server.sun_family = AF_UNIX;
b6e6e716 213 Ustrcpy(server.sun_path, spamd_address_work);
8523533c
TK
214
215 if (connect(spamd_sock, (struct sockaddr *) &server, sizeof(struct sockaddr_un)) < 0) {
216 log_write(0, LOG_MAIN|LOG_PANIC,
217 "malware acl condition: spamd: unable to connect to UNIX socket %s (%s)",
b6e6e716 218 spamd_address_work, strerror(errno) );
f1e894f3
PH
219 (void)fclose(mbox_file);
220 (void)close(spamd_sock);
8523533c
TK
221 return DEFER;
222 }
223
224 }
225
0f501486
PP
226 if (spamd_sock == -1) {
227 log_write(0, LOG_MAIN|LOG_PANIC,
228 "programming fault, spamd_sock unexpectedly unset");
229 (void)fclose(mbox_file);
230 (void)close(spamd_sock);
231 return DEFER;
232 }
233
8523533c 234 /* now we are connected to spamd on spamd_sock */
b07e6aa3 235 (void)string_format(spamd_buffer,
8523533c 236 sizeof(spamd_buffer),
f7b63901 237 "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
8523533c
TK
238 user_name,
239 mbox_size);
240
241 /* send our request */
242 if (send(spamd_sock, spamd_buffer, Ustrlen(spamd_buffer), 0) < 0) {
f1e894f3 243 (void)close(spamd_sock);
8523533c
TK
244 log_write(0, LOG_MAIN|LOG_PANIC,
245 "spam acl condition: spamd send failed: %s", strerror(errno));
f1e894f3
PH
246 (void)fclose(mbox_file);
247 (void)close(spamd_sock);
8523533c
TK
248 return DEFER;
249 };
250
251 /* now send the file */
cfe75fc3
PH
252 /* spamd sometimes accepts conections but doesn't read data off
253 * the connection. We make the file descriptor non-blocking so
254 * that the write will only write sufficient data without blocking
255 * and we poll the desciptor to make sure that we can write without
256 * blocking. Short writes are gracefully handled and if the whole
257 * trasaction takes too long it is aborted.
25257489
PH
258 * Note: poll() is not supported in OSX 10.2 and is reported to be
259 * broken in more recent versions (up to 10.4).
cfe75fc3 260 */
f452e07e 261#ifndef NO_POLL_H
cfe75fc3
PH
262 pollfd.fd = spamd_sock;
263 pollfd.events = POLLOUT;
f452e07e 264#endif
ff790e47 265 (void)fcntl(spamd_sock, F_SETFL, O_NONBLOCK);
8523533c 266 do {
cfe75fc3
PH
267 read = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
268 if (read > 0) {
269 offset = 0;
270again:
f452e07e 271#ifndef NO_POLL_H
cfe75fc3 272 result = poll(&pollfd, 1, 1000);
25257489
PH
273
274/* Patch posted by Erik ? for OS X and applied by PH */
275#else
276 select_tv.tv_sec = 1;
277 select_tv.tv_usec = 0;
278 FD_ZERO(&select_fd);
279 FD_SET(spamd_sock, &select_fd);
280 result = select(spamd_sock+1, NULL, &select_fd, NULL, &select_tv);
281#endif
282/* End Erik's patch */
283
cfe75fc3 284 if (result == -1 && errno == EINTR)
25257489 285 goto again;
cfe75fc3
PH
286 else if (result < 1) {
287 if (result == -1)
288 log_write(0, LOG_MAIN|LOG_PANIC,
289 "spam acl condition: %s on spamd socket", strerror(errno));
290 else {
291 if (time(NULL) - start < SPAMD_TIMEOUT)
c007c974 292 goto again;
cfe75fc3
PH
293 log_write(0, LOG_MAIN|LOG_PANIC,
294 "spam acl condition: timed out writing spamd socket");
295 }
f1e894f3
PH
296 (void)close(spamd_sock);
297 (void)fclose(mbox_file);
8523533c 298 return DEFER;
cfe75fc3 299 }
25257489 300
cfe75fc3 301 wrote = send(spamd_sock,spamd_buffer + offset,read - offset,0);
8d7d227d
TK
302 if (wrote == -1)
303 {
304 log_write(0, LOG_MAIN|LOG_PANIC,
305 "spam acl condition: %s on spamd socket", strerror(errno));
f1e894f3
PH
306 (void)close(spamd_sock);
307 (void)fclose(mbox_file);
8d7d227d
TK
308 return DEFER;
309 }
cfe75fc3
PH
310 if (offset + wrote != read) {
311 offset += wrote;
312 goto again;
313 }
314 }
315 }
316 while (!feof(mbox_file) && !ferror(mbox_file));
317 if (ferror(mbox_file)) {
318 log_write(0, LOG_MAIN|LOG_PANIC,
319 "spam acl condition: error reading spool file: %s", strerror(errno));
f1e894f3
PH
320 (void)close(spamd_sock);
321 (void)fclose(mbox_file);
cfe75fc3 322 return DEFER;
8523533c 323 }
8523533c 324
f1e894f3 325 (void)fclose(mbox_file);
8523533c
TK
326
327 /* we're done sending, close socket for writing */
328 shutdown(spamd_sock,SHUT_WR);
8e669ac1 329
cfe75fc3
PH
330 /* read spamd response using what's left of the timeout.
331 */
8523533c
TK
332 memset(spamd_buffer, 0, sizeof(spamd_buffer));
333 offset = 0;
334 while((i = ip_recv(spamd_sock,
335 spamd_buffer + offset,
336 sizeof(spamd_buffer) - offset - 1,
cfe75fc3 337 SPAMD_TIMEOUT - time(NULL) + start)) > 0 ) {
8523533c
TK
338 offset += i;
339 }
340
341 /* error handling */
342 if((i <= 0) && (errno != 0)) {
343 log_write(0, LOG_MAIN|LOG_PANIC,
344 "spam acl condition: error reading from spamd socket: %s", strerror(errno));
f1e894f3 345 (void)close(spamd_sock);
8523533c
TK
346 return DEFER;
347 }
348
349 /* reading done */
f1e894f3 350 (void)close(spamd_sock);
8523533c
TK
351
352 /* dig in the spamd output and put the report in a multiline header, if requested */
0806a9c5 353 if( sscanf(CS spamd_buffer,"SPAMD/%7s 0 EX_OK\r\nContent-length: %*u\r\n\r\n%lf/%lf\r\n%n",
8523533c 354 spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
8e669ac1 355
8523533c 356 /* try to fall back to pre-2.50 spamd output */
0806a9c5 357 if( sscanf(CS spamd_buffer,"SPAMD/%7s 0 EX_OK\r\nSpam: %*s ; %lf / %lf\r\n\r\n%n",
8523533c
TK
358 spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
359 log_write(0, LOG_MAIN|LOG_PANIC,
360 "spam acl condition: cannot parse spamd output");
361 return DEFER;
362 };
363 };
364
365 /* Create report. Since this is a multiline string,
366 we must hack it into shape first */
367 p = &spamd_buffer[spamd_report_offset];
368 q = spam_report_buffer;
369 while (*p != '\0') {
370 /* skip \r */
371 if (*p == '\r') {
372 p++;
373 continue;
374 };
375 *q = *p;
376 q++;
377 if (*p == '\n') {
89dec7b6
TF
378 /* add an extra space after the newline to ensure
379 that it is treated as a header continuation line */
380 *q = ' ';
8523533c 381 q++;
8523533c
TK
382 };
383 p++;
384 };
385 /* NULL-terminate */
386 *q = '\0';
387 q--;
388 /* cut off trailing leftovers */
389 while (*q <= ' ') {
390 *q = '\0';
391 q--;
392 };
393 spam_report = spam_report_buffer;
394
395 /* create spam bar */
396 spamd_score_char = spamd_score > 0 ? '+' : '-';
397 j = abs((int)(spamd_score));
398 i = 0;
399 if( j != 0 ) {
400 while((i < j) && (i <= MAX_SPAM_BAR_CHARS))
401 spam_bar_buffer[i++] = spamd_score_char;
402 }
403 else{
404 spam_bar_buffer[0] = '/';
405 i = 1;
406 }
407 spam_bar_buffer[i] = '\0';
408 spam_bar = spam_bar_buffer;
409
410 /* create "float" spam score */
b07e6aa3 411 (void)string_format(spam_score_buffer, sizeof(spam_score_buffer),"%.1f", spamd_score);
8523533c
TK
412 spam_score = spam_score_buffer;
413
414 /* create "int" spam score */
415 j = (int)((spamd_score + 0.001)*10);
b07e6aa3 416 (void)string_format(spam_score_int_buffer, sizeof(spam_score_int_buffer), "%d", j);
8523533c
TK
417 spam_score_int = spam_score_int_buffer;
418
419 /* compare threshold against score */
420 if (spamd_score >= spamd_threshold) {
421 /* spam as determined by user's threshold */
422 spam_rc = OK;
423 }
424 else {
425 /* not spam */
426 spam_rc = FAIL;
427 };
8e669ac1 428
f7274286
PP
429 /* remember expanded spamd_address if needed */
430 if (spamd_address_work != spamd_address) {
431 prev_spamd_address_work = string_copy(spamd_address_work);
b6e6e716 432 }
f7274286
PP
433 /* remember user name and "been here" for it */
434 Ustrcpy(prev_user_name, user_name);
435 spam_ok = 1;
8e669ac1 436
8523533c
TK
437 if (override) {
438 /* always return OK, no matter what the score */
439 return OK;
440 }
441 else {
442 return spam_rc;
443 };
444}
445
446#endif