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
  24 spam(uschar **listptr)
  25 {
  26   int sep = 0;
  27   uschar *list = *listptr;
  28   uschar *user_name;
  29   uschar user_name_buffer[128];
  30   unsigned long mbox_size;
  31   FILE *mbox_file;
  32   int spamd_sock = -1;
  33   uschar spamd_buffer[32600];
  34   int i, j, offset, result;
  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;
  41   time_t start;
  42   size_t read, wrote;
  43   struct sockaddr_un server;
  44 #ifndef NO_POLL_H
  45   struct pollfd pollfd;
  46 #else                               /* Patch posted by Erik ? for OS X */
  47   struct timeval select_tv;         /* and applied by PH */
  48   fd_set select_fd;
  49 #endif
  50   uschar *spamd_address_work;
  51   static const char * loglabel = US"spam acl condition:";
  52
  53   /* stop compiler warning */
  54   result = 0;
  55
  56   /* find the username from the option list */
  57   if ((user_name = string_nextinlist(&list, &sep,
  58                                      user_name_buffer,
  59                                      sizeof(user_name_buffer))) == NULL)
  60     {
  61     /* no username given, this means no scanning should be done */
  62     return FAIL;
  63     }
  64
  65   /* if username is "0" or "false", do not scan */
  66   if ( (Ustrcmp(user_name,"0") == 0) ||
  67        (strcmpic(user_name,US"false") == 0) )
  68     return FAIL;
  69
  70   /* if there is an additional option, check if it is "true" */
  71   if (strcmpic(list,US"true") == 0)
  72     /* in that case, always return true later */
  73     override = 1;
  74
  75   /* expand spamd_address if needed */
  76   if (*spamd_address == '$')
  77     {
  78     spamd_address_work = expand_string(spamd_address);
  79     if (spamd_address_work == NULL)
  80       {
  81       log_write(0, LOG_MAIN|LOG_PANIC,
  82         "%s spamd_address starts with $, but expansion failed: %s",
  83         loglabel, expand_string_message);
  84       return DEFER;
  85       }
  86     }
  87   else
  88     spamd_address_work = spamd_address;
  89
  90   /* check if previous spamd_address was expanded and has changed. dump cached results if so */
  91   if (  spam_ok
  92      && prev_spamd_address_work != NULL
  93      && Ustrcmp(prev_spamd_address_work, spamd_address_work) != 0
  94      )
  95     spam_ok = 0;
  96
  97   /* if we scanned for this username last time, just return */
  98   if ( spam_ok && Ustrcmp(prev_user_name, user_name) == 0)
  99     if (override)
 100       return OK;
 101     else
 102       return spam_rc;
 103
 104   /* make sure the eml mbox file is spooled up */
 105   mbox_file = spool_mbox(&mbox_size, NULL);
 106
 107   if (mbox_file == NULL)
 108     {
 109     /* error while spooling */
 110     log_write(0, LOG_MAIN|LOG_PANIC,
 111            "%s error while creating mbox spool file", loglabel);
 112     return DEFER;
 113     }
 114
 115   start = time(NULL);
 116
 117   /* socket does not start with '/' -> network socket */
 118   if (*spamd_address_work != '/')
 119     {
 120     int num_servers = 0;
 121     int current_server;
 122     uschar *address = NULL;
 123     uschar *spamd_address_list_ptr = spamd_address_work;
 124     uschar address_buffer[256];
 125     spamd_address_container * spamd_address_vector[32];
 126
 127     /* Check how many spamd servers we have
 128        and register their addresses */
 129     while ((address = string_nextinlist(&spamd_address_list_ptr, &sep,
 130                                         address_buffer,
 131                                         sizeof(address_buffer))) != NULL)
 132       {
 133
 134       /* Potential memory leak as we never free the store. */
 135       spamd_address_container *this_spamd =
 136         (spamd_address_container *)store_get(sizeof(spamd_address_container));
 137
 138       /* grok spamd address and port */
 139       if (sscanf(CS address, "%23s %u", this_spamd->tcp_addr, &(this_spamd->tcp_port)) != 2)
 140         {
 141         log_write(0, LOG_MAIN,
 142           "%s warning - invalid spamd address: '%s'", loglabel, address);
 143         continue;
 144         }
 145
 146       spamd_address_vector[num_servers] = this_spamd;
 147       if (  ++num_servers
 148          >= sizeof(spamd_address_vector)/sizeof(spamd_address_vector[0]))
 149         break;
 150       }
 151
 152     /* check if we have at least one server */
 153     if (!num_servers)
 154       {
 155       log_write(0, LOG_MAIN|LOG_PANIC,
 156          "%s no useable spamd server addresses in spamd_address configuration option.",
 157          loglabel);
 158       (void)fclose(mbox_file);
 159       return DEFER;
 160       }
 161
 162     while (num_servers > 0)
 163       {
 164       int i;
 165
 166       /* Randomly pick a server to try */
 167       current_server = random_number(num_servers);
 168
 169       debug_printf("trying server %s, port %u\n",
 170                    spamd_address_vector[current_server]->tcp_addr,
 171                    spamd_address_vector[current_server]->tcp_port);
 172
 173       /* contact a spamd */
 174       if ((spamd_sock = ip_socket(SOCK_STREAM, AF_INET)) < 0)
 175         {
 176         log_write(0, LOG_MAIN|LOG_PANIC,
 177            "%s error creating IP socket for spamd", loglabel);
 178         (void)fclose(mbox_file);
 179         return DEFER;
 180         }
 181
 182       if (ip_connect(spamd_sock,
 183                      AF_INET,
 184                      spamd_address_vector[current_server]->tcp_addr,
 185                      spamd_address_vector[current_server]->tcp_port,
 186                      5 ) > -1)
 187         /* connection OK */
 188         break;
 189
 190       log_write(0, LOG_MAIN|LOG_PANIC,
 191          "%s warning - spamd connection to %s, port %u failed: %s",
 192          loglabel,
 193          spamd_address_vector[current_server]->tcp_addr,
 194          spamd_address_vector[current_server]->tcp_port,
 195          strerror(errno));
 196
 197       (void)close(spamd_sock);
 198
 199       /* Remove the server from the list. XXX We should free the memory */
 200       num_servers--;
 201       for (i = current_server; i < num_servers; i++)
 202         spamd_address_vector[i] = spamd_address_vector[i+1];
 203       }
 204
 205     if (num_servers == 0)
 206       {
 207       log_write(0, LOG_MAIN|LOG_PANIC, "%s all spamd servers failed", loglabel);
 208       (void)fclose(mbox_file);
 209       return DEFER;
 210       }
 211     }
 212   else
 213     {
 214     /* open the local socket */
 215
 216     if ((spamd_sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
 217       {
 218       log_write(0, LOG_MAIN|LOG_PANIC,
 219                 "%s spamd: unable to acquire socket (%s)",
 220                 loglabel,
 221                 strerror(errno));
 222       (void)fclose(mbox_file);
 223       return DEFER;
 224       }
 225
 226     server.sun_family = AF_UNIX;
 227     Ustrcpy(server.sun_path, spamd_address_work);
 228
 229     if (connect(spamd_sock, (struct sockaddr *) &server, sizeof(struct sockaddr_un)) < 0)
 230       {
 231       log_write(0, LOG_MAIN|LOG_PANIC,
 232                 "%s spamd: unable to connect to UNIX socket %s (%s)",
 233                 loglabel,
 234                 spamd_address_work, strerror(errno) );
 235       (void)fclose(mbox_file);
 236       (void)close(spamd_sock);
 237       return DEFER;
 238       }
 239     }
 240
 241   if (spamd_sock == -1)
 242     {
 243     log_write(0, LOG_MAIN|LOG_PANIC,
 244         "programming fault, spamd_sock unexpectedly unset");
 245     (void)fclose(mbox_file);
 246     (void)close(spamd_sock);
 247     return DEFER;
 248     }
 249
 250   /* now we are connected to spamd on spamd_sock */
 251   (void)string_format(spamd_buffer,
 252            sizeof(spamd_buffer),
 253            "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
 254            user_name,
 255            mbox_size);
 256
 257   /* send our request */
 258   if (send(spamd_sock, spamd_buffer, Ustrlen(spamd_buffer), 0) < 0)
 259     {
 260     (void)close(spamd_sock);
 261     log_write(0, LOG_MAIN|LOG_PANIC,
 262          "%s spamd send failed: %s", loglabel, strerror(errno));
 263     (void)fclose(mbox_file);
 264     (void)close(spamd_sock);
 265     return DEFER;
 266     }
 267
 268   /* now send the file */
 269   /* spamd sometimes accepts conections but doesn't read data off
 270    * the connection.  We make the file descriptor non-blocking so
 271    * that the write will only write sufficient data without blocking
 272    * and we poll the desciptor to make sure that we can write without
 273    * blocking.  Short writes are gracefully handled and if the whole
 274    * trasaction takes too long it is aborted.
 275    * Note: poll() is not supported in OSX 10.2 and is reported to be
 276    *       broken in more recent versions (up to 10.4).
 277    */
 278 #ifndef NO_POLL_H
 279   pollfd.fd = spamd_sock;
 280   pollfd.events = POLLOUT;
 281 #endif
 282   (void)fcntl(spamd_sock, F_SETFL, O_NONBLOCK);
 283   do
 284     {
 285     read = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
 286     if (read > 0)
 287       {
 288       offset = 0;
 289 again:
 290 #ifndef NO_POLL_H
 291       result = poll(&pollfd, 1, 1000);
 292
 293 /* Patch posted by Erik ? for OS X and applied by PH */
 294 #else
 295       select_tv.tv_sec = 1;
 296       select_tv.tv_usec = 0;
 297       FD_ZERO(&select_fd);
 298       FD_SET(spamd_sock, &select_fd);
 299       result = select(spamd_sock+1, NULL, &select_fd, NULL, &select_tv);
 300 #endif
 301 /* End Erik's patch */
 302
 303       if (result == -1 && errno == EINTR)
 304         goto again;
 305       else if (result < 1)
 306         {
 307         if (result == -1)
 308           log_write(0, LOG_MAIN|LOG_PANIC,
 309             "%s %s on spamd socket", loglabel, strerror(errno));
 310         else
 311           {
 312           if (time(NULL) - start < SPAMD_TIMEOUT)
 313             goto again;
 314           log_write(0, LOG_MAIN|LOG_PANIC,
 315             "%s timed out writing spamd socket", loglabel);
 316           }
 317         (void)close(spamd_sock);
 318         (void)fclose(mbox_file);
 319         return DEFER;
 320         }
 321
 322       wrote = send(spamd_sock,spamd_buffer + offset,read - offset,0);
 323       if (wrote == -1)
 324         {
 325         log_write(0, LOG_MAIN|LOG_PANIC,
 326             "%s %s on spamd socket", loglabel, strerror(errno));
 327         (void)close(spamd_sock);
 328         (void)fclose(mbox_file);
 329         return DEFER;
 330         }
 331       if (offset + wrote != read)
 332         {
 333         offset += wrote;
 334         goto again;
 335         }
 336       }
 337     }
 338   while (!feof(mbox_file) && !ferror(mbox_file));
 339
 340   if (ferror(mbox_file))
 341     {
 342     log_write(0, LOG_MAIN|LOG_PANIC,
 343       "%s error reading spool file: %s", loglabel, strerror(errno));
 344     (void)close(spamd_sock);
 345     (void)fclose(mbox_file);
 346     return DEFER;
 347     }
 348
 349   (void)fclose(mbox_file);
 350
 351   /* we're done sending, close socket for writing */
 352   shutdown(spamd_sock,SHUT_WR);
 353
 354   /* read spamd response using what's left of the timeout.
 355    */
 356   memset(spamd_buffer, 0, sizeof(spamd_buffer));
 357   offset = 0;
 358   while ((i = ip_recv(spamd_sock,
 359                      spamd_buffer + offset,
 360                      sizeof(spamd_buffer) - offset - 1,
 361                      SPAMD_TIMEOUT - time(NULL) + start)) > 0 )
 362     offset += i;
 363
 364   /* error handling */
 365   if (i <= 0 && errno != 0)
 366     {
 367     log_write(0, LOG_MAIN|LOG_PANIC,
 368          "%s error reading from spamd socket: %s", loglabel, strerror(errno));
 369     (void)close(spamd_sock);
 370     return DEFER;
 371     }
 372
 373   /* reading done */
 374   (void)close(spamd_sock);
 375
 376   /* dig in the spamd output and put the report in a multiline header, if requested */
 377   if (sscanf(CS spamd_buffer,
 378               "SPAMD/%7s 0 EX_OK\r\nContent-length: %*u\r\n\r\n%lf/%lf\r\n%n",
 379               spamd_version, &spamd_score, &spamd_threshold,
 380               &spamd_report_offset) != 3)
 381     {
 382
 383     /* try to fall back to pre-2.50 spamd output */
 384     if (sscanf(CS spamd_buffer,
 385                 "SPAMD/%7s 0 EX_OK\r\nSpam: %*s ; %lf / %lf\r\n\r\n%n",
 386                 spamd_version, &spamd_score, &spamd_threshold,
 387                 &spamd_report_offset) != 3 )
 388       {
 389       log_write(0, LOG_MAIN|LOG_PANIC,
 390          "%s cannot parse spamd output", loglabel);
 391       return DEFER;
 392       }
 393     }
 394
 395   /* Create report. Since this is a multiline string,
 396   we must hack it into shape first */
 397   p = &spamd_buffer[spamd_report_offset];
 398   q = spam_report_buffer;
 399   while (*p != '\0')
 400     {
 401     /* skip \r */
 402     if (*p == '\r')
 403       {
 404       p++;
 405       continue;
 406       }
 407     *q++ = *p;
 408     if (*p++ == '\n')
 409       {
 410       /* add an extra space after the newline to ensure
 411       that it is treated as a header continuation line */
 412       *q++ = ' ';
 413       }
 414     }
 415   /* NULL-terminate */
 416   *q-- = '\0';
 417   /* cut off trailing leftovers */
 418   while (*q <= ' ')
 419     *q-- = '\0';
 420
 421   spam_report = spam_report_buffer;
 422
 423   /* create spam bar */
 424   spamd_score_char = spamd_score > 0 ? '+' : '-';
 425   j = abs((int)(spamd_score));
 426   i = 0;
 427   if (j != 0)
 428     while ((i < j) && (i <= MAX_SPAM_BAR_CHARS))
 429        spam_bar_buffer[i++] = spamd_score_char;
 430   else
 431     {
 432     spam_bar_buffer[0] = '/';
 433     i = 1;
 434     }
 435   spam_bar_buffer[i] = '\0';
 436   spam_bar = spam_bar_buffer;
 437
 438   /* create "float" spam score */
 439   (void)string_format(spam_score_buffer, sizeof(spam_score_buffer),"%.1f", spamd_score);
 440   spam_score = spam_score_buffer;
 441
 442   /* create "int" spam score */
 443   j = (int)((spamd_score + 0.001)*10);
 444   (void)string_format(spam_score_int_buffer, sizeof(spam_score_int_buffer), "%d", j);
 445   spam_score_int = spam_score_int_buffer;
 446
 447   /* compare threshold against score */
 448   if (spamd_score >= spamd_threshold)
 449     {
 450     /* spam as determined by user's threshold */
 451     spam_rc = OK;
 452     }
 453   else
 454     {
 455     /* not spam */
 456     spam_rc = FAIL;
 457     }
 458
 459   /* remember expanded spamd_address if needed */
 460   if (spamd_address_work != spamd_address)
 461     prev_spamd_address_work = string_copy(spamd_address_work);
 462
 463   /* remember user name and "been here" for it */
 464   Ustrcpy(prev_user_name, user_name);
 465   spam_ok = 1;
 466
 467   if (override) /* always return OK, no matter what the score */
 468     return OK;
 469   else
 470     return spam_rc;
 471 }
 472
 473 #endif