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