src/src/spam.c

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