src/src/spam.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2003 - 2015
   6  * License: GPL
   7  * Copyright (c) The Exim Maintainers 2016 - 2018
   8  */
   9
  10 /* Code for calling spamassassin's spamd. Called from acl.c. */
  11
  12 #include "exim.h"
  13 #ifdef WITH_CONTENT_SCAN
  14 #include "spam.h"
  15
  16 uschar spam_score_buffer[16];
  17 uschar spam_score_int_buffer[16];
  18 uschar spam_bar_buffer[128];
  19 uschar * spam_action_buffer;
  20 uschar spam_report_buffer[32600];
  21 uschar prev_user_name[128] = "";
  22 int spam_ok = 0;
  23 int spam_rc = 0;
  24 uschar *prev_spamd_address_work = NULL;
  25
  26 static const uschar * loglabel = US"spam acl condition:";
  27
  28
  29 static int
  30 spamd_param_init(spamd_address_container *spamd)
  31 {
  32 /* default spamd server weight, time and priority value */
  33 spamd->is_failed = FALSE;
  34 spamd->weight = SPAMD_WEIGHT;
  35 spamd->timeout = SPAMD_TIMEOUT;
  36 spamd->retry = 0;
  37 spamd->priority = 1;
  38 return 0;
  39 }
  40
  41
  42 static int
  43 spamd_param(const uschar * param, spamd_address_container * spamd)
  44 {
  45 static int timesinceday = -1;
  46 const uschar * s;
  47 const uschar * name;
  48
  49 /*XXX more clever parsing could discard embedded spaces? */
  50
  51 if (sscanf(CCS param, "pri=%u", &spamd->priority))
  52   return 0; /* OK */
  53
  54 if (sscanf(CCS param, "weight=%u", &spamd->weight))
  55   {
  56   if (spamd->weight == 0) /* this server disabled: skip it */
  57     return 1;
  58   return 0; /* OK */
  59   }
  60
  61 if (Ustrncmp(param, "time=", 5) == 0)
  62   {
  63   unsigned int start_h = 0, start_m = 0, start_s = 0;
  64   unsigned int end_h = 24, end_m = 0, end_s = 0;
  65   unsigned int time_start, time_end;
  66   const uschar * end_string;
  67
  68   name = US"time";
  69   s = param+5;
  70   if ((end_string = Ustrchr(s, '-')))
  71     {
  72     end_string++;
  73     if (  sscanf(CS end_string, "%u.%u.%u", &end_h,   &end_m,   &end_s)   == 0
  74        || sscanf(CS s,          "%u.%u.%u", &start_h, &start_m, &start_s) == 0
  75        )
  76       goto badval;
  77     }
  78   else
  79     goto badval;
  80
  81   if (timesinceday < 0)
  82     {
  83     time_t now = time(NULL);
  84     struct tm *tmp = localtime(&now);
  85     timesinceday = tmp->tm_hour*3600 + tmp->tm_min*60 + tmp->tm_sec;
  86     }
  87
  88   time_start = start_h*3600 + start_m*60 + start_s;
  89   time_end = end_h*3600 + end_m*60 + end_s;
  90
  91   if (timesinceday < time_start || timesinceday >= time_end)
  92     return 1; /* skip spamd server */
  93
  94   return 0; /* OK */
  95   }
  96
  97 if (Ustrncmp(param, "tmo=", 4) == 0)
  98   {
  99   int sec = readconf_readtime((s = param+4), '\0', FALSE);
 100   name = US"timeout";
 101   if (sec < 0)
 102     goto badval;
 103   spamd->timeout = sec;
 104   return 0;
 105   }
 106
 107 if (Ustrncmp(param, "retry=", 6) == 0)
 108   {
 109   int sec = readconf_readtime((s = param+6), '\0', FALSE);
 110   name = US"retry";
 111   if (sec < 0)
 112     goto badval;
 113   spamd->retry = sec;
 114   return 0;
 115   }
 116
 117 log_write(0, LOG_MAIN, "%s warning - invalid spamd parameter: '%s'",
 118   loglabel, param);
 119 return -1; /* syntax error */
 120
 121 badval:
 122   log_write(0, LOG_MAIN,
 123     "%s warning - invalid spamd %s value: '%s'", loglabel, name, s);
 124   return -1; /* syntax error */
 125 }
 126
 127
 128 static int
 129 spamd_get_server(spamd_address_container ** spamds, int num_servers)
 130 {
 131 unsigned int i;
 132 spamd_address_container * sd;
 133 long rnd, weights;
 134 unsigned pri;
 135 static BOOL srandomed = FALSE;
 136
 137 /* speedup, if we have only 1 server */
 138 if (num_servers == 1)
 139   return (spamds[0]->is_failed ? -1 : 0);
 140
 141 /* init ranmod */
 142 if (!srandomed)
 143   {
 144   struct timeval tv;
 145   gettimeofday(&tv, NULL);
 146   srandom((unsigned int)(tv.tv_usec/1000));
 147   srandomed = TRUE;
 148   }
 149
 150 /* scan for highest pri */
 151 for (pri = 0, i = 0; i < num_servers; i++)
 152   {
 153   sd = spamds[i];
 154   if (!sd->is_failed && sd->priority > pri) pri = sd->priority;
 155   }
 156
 157 /* get sum of weights */
 158 for (weights = 0, i = 0; i < num_servers; i++)
 159   {
 160   sd = spamds[i];
 161   if (!sd->is_failed && sd->priority == pri) weights += sd->weight;
 162   }
 163 if (weights == 0)       /* all servers failed */
 164   return -1;
 165
 166 for (rnd = random() % weights, i = 0; i < num_servers; i++)
 167   {
 168   sd = spamds[i];
 169   if (!sd->is_failed && sd->priority == pri)
 170     if ((rnd -= sd->weight) <= 0)
 171       return i;
 172   }
 173
 174 log_write(0, LOG_MAIN|LOG_PANIC,
 175   "%s unknown error (memory/cpu corruption?)", loglabel);
 176 return -1;
 177 }
 178
 179
 180 int
 181 spam(const uschar **listptr)
 182 {
 183 int sep = 0;
 184 const uschar *list = *listptr;
 185 uschar *user_name;
 186 uschar user_name_buffer[128];
 187 unsigned long mbox_size;
 188 FILE *mbox_file;
 189 client_conn_ctx spamd_cctx = {.sock = -1};
 190 uschar spamd_buffer[32600];
 191 int i, j, offset, result;
 192 uschar spamd_version[8];
 193 uschar spamd_short_result[8];
 194 uschar spamd_score_char;
 195 double spamd_threshold, spamd_score, spamd_reject_score;
 196 int spamd_report_offset;
 197 uschar *p,*q;
 198 int override = 0;
 199 time_t start;
 200 size_t read, wrote;
 201 #ifndef NO_POLL_H
 202 struct pollfd pollfd;
 203 #else                               /* Patch posted by Erik ? for OS X */
 204 struct timeval select_tv;         /* and applied by PH */
 205 fd_set select_fd;
 206 #endif
 207 uschar *spamd_address_work;
 208 spamd_address_container * sd;
 209
 210 /* stop compiler warning */
 211 result = 0;
 212
 213 /* find the username from the option list */
 214 if ((user_name = string_nextinlist(&list, &sep,
 215                                    user_name_buffer,
 216                                    sizeof(user_name_buffer))) == NULL)
 217   {
 218   /* no username given, this means no scanning should be done */
 219   return FAIL;
 220   }
 221
 222 /* if username is "0" or "false", do not scan */
 223 if ( (Ustrcmp(user_name,"0") == 0) ||
 224      (strcmpic(user_name,US"false") == 0) )
 225   return FAIL;
 226
 227 /* if there is an additional option, check if it is "true" */
 228 if (strcmpic(list,US"true") == 0)
 229   /* in that case, always return true later */
 230   override = 1;
 231
 232 /* expand spamd_address if needed */
 233 if (*spamd_address == '$')
 234   {
 235   spamd_address_work = expand_string(spamd_address);
 236   if (spamd_address_work == NULL)
 237     {
 238     log_write(0, LOG_MAIN|LOG_PANIC,
 239       "%s spamd_address starts with $, but expansion failed: %s",
 240       loglabel, expand_string_message);
 241     return DEFER;
 242     }
 243   }
 244 else
 245   spamd_address_work = spamd_address;
 246
 247 DEBUG(D_acl) debug_printf_indent("spamd: addrlist '%s'\n", spamd_address_work);
 248
 249 /* check if previous spamd_address was expanded and has changed. dump cached results if so */
 250 if (  spam_ok
 251    && prev_spamd_address_work != NULL
 252    && Ustrcmp(prev_spamd_address_work, spamd_address_work) != 0
 253    )
 254   spam_ok = 0;
 255
 256 /* if we scanned for this username last time, just return */
 257 if (spam_ok && Ustrcmp(prev_user_name, user_name) == 0)
 258   return override ? OK : spam_rc;
 259
 260 /* make sure the eml mbox file is spooled up */
 261
 262 if (!(mbox_file = spool_mbox(&mbox_size, NULL, NULL)))
 263   {                                                             /* error while spooling */
 264   log_write(0, LOG_MAIN|LOG_PANIC,
 265          "%s error while creating mbox spool file", loglabel);
 266   return DEFER;
 267   }
 268
 269 start = time(NULL);
 270
 271   {
 272   int num_servers = 0;
 273   int current_server;
 274   uschar * address;
 275   const uschar * spamd_address_list_ptr = spamd_address_work;
 276   spamd_address_container * spamd_address_vector[32];
 277
 278   /* Check how many spamd servers we have
 279      and register their addresses */
 280   sep = 0;                              /* default colon-sep */
 281   while ((address = string_nextinlist(&spamd_address_list_ptr, &sep, NULL, 0)))
 282     {
 283     const uschar * sublist;
 284     int sublist_sep = -(int)' ';        /* default space-sep */
 285     unsigned args;
 286     uschar * s;
 287
 288     DEBUG(D_acl) debug_printf_indent("spamd: addr entry '%s'\n", address);
 289     sd = (spamd_address_container *)store_get(sizeof(spamd_address_container));
 290
 291     for (sublist = address, args = 0, spamd_param_init(sd);
 292          (s = string_nextinlist(&sublist, &sublist_sep, NULL, 0));
 293          args++
 294          )
 295       {
 296         DEBUG(D_acl) debug_printf_indent("spamd:  addr parm '%s'\n", s);
 297         switch (args)
 298         {
 299         case 0:   sd->hostspec = s;
 300                   if (*s == '/') args++;        /* local; no port */
 301                   break;
 302         case 1:   sd->hostspec = string_sprintf("%s %s", sd->hostspec, s);
 303                   break;
 304         default:  spamd_param(s, sd);
 305                   break;
 306         }
 307       }
 308     if (args < 2)
 309       {
 310       log_write(0, LOG_MAIN,
 311         "%s warning - invalid spamd address: '%s'", loglabel, address);
 312       continue;
 313       }
 314
 315     spamd_address_vector[num_servers] = sd;
 316     if (++num_servers > 31)
 317       break;
 318     }
 319
 320   /* check if we have at least one server */
 321   if (!num_servers)
 322     {
 323     log_write(0, LOG_MAIN|LOG_PANIC,
 324        "%s no useable spamd server addresses in spamd_address configuration option.",
 325        loglabel);
 326     goto defer;
 327     }
 328
 329   current_server = spamd_get_server(spamd_address_vector, num_servers);
 330   sd = spamd_address_vector[current_server];
 331   for(;;)
 332     {
 333     uschar * errstr;
 334
 335     DEBUG(D_acl) debug_printf_indent("spamd: trying server %s\n", sd->hostspec);
 336
 337     for (;;)
 338       {
 339       /*XXX could potentially use TFO early-data here */
 340       if (  (spamd_cctx.sock = ip_streamsocket(sd->hostspec, &errstr, 5)) >= 0
 341          || sd->retry <= 0
 342          )
 343         break;
 344       DEBUG(D_acl) debug_printf_indent("spamd: server %s: retry conn\n", sd->hostspec);
 345       while (sd->retry > 0) sd->retry = sleep(sd->retry);
 346       }
 347     if (spamd_cctx.sock >= 0)
 348       break;
 349
 350     log_write(0, LOG_MAIN, "%s spamd: %s", loglabel, errstr);
 351     sd->is_failed = TRUE;
 352
 353     current_server = spamd_get_server(spamd_address_vector, num_servers);
 354     if (current_server < 0)
 355       {
 356       log_write(0, LOG_MAIN|LOG_PANIC, "%s all spamd servers failed", loglabel);
 357       goto defer;
 358       }
 359     sd = spamd_address_vector[current_server];
 360     }
 361   }
 362
 363 (void)fcntl(spamd_cctx.sock, F_SETFL, O_NONBLOCK);
 364 /* now we are connected to spamd on spamd_sock */
 365
 366 (void)string_format(spamd_buffer,
 367         sizeof(spamd_buffer),
 368         "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
 369         user_name,
 370         mbox_size);
 371 /* send our request */
 372 wrote = send(spamd_cctx.sock, spamd_buffer, Ustrlen(spamd_buffer), 0);
 373
 374 if (wrote == -1)
 375   {
 376   (void)close(spamd_cctx.sock);
 377   log_write(0, LOG_MAIN|LOG_PANIC,
 378        "%s spamd %s send failed: %s", loglabel, callout_address, strerror(errno));
 379   goto defer;
 380   }
 381
 382 /* now send the file */
 383 /* spamd sometimes accepts connections but doesn't read data off
 384  * the connection.  We make the file descriptor non-blocking so
 385  * that the write will only write sufficient data without blocking
 386  * and we poll the descriptor to make sure that we can write without
 387  * blocking.  Short writes are gracefully handled and if the whole
 388  * transaction takes too long it is aborted.
 389  * Note: poll() is not supported in OSX 10.2 and is reported to be
 390  *       broken in more recent versions (up to 10.4).
 391  */
 392 #ifndef NO_POLL_H
 393 pollfd.fd = spamd_cctx.sock;
 394 pollfd.events = POLLOUT;
 395 #endif
 396 do
 397   {
 398   read = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
 399   if (read > 0)
 400     {
 401     offset = 0;
 402 again:
 403 #ifndef NO_POLL_H
 404     result = poll(&pollfd, 1, 1000);
 405
 406 /* Patch posted by Erik ? for OS X and applied by PH */
 407 #else
 408     select_tv.tv_sec = 1;
 409     select_tv.tv_usec = 0;
 410     FD_ZERO(&select_fd);
 411     FD_SET(spamd_cctx.sock, &select_fd);
 412     result = select(spamd_cctx.sock+1, NULL, &select_fd, NULL, &select_tv);
 413 #endif
 414 /* End Erik's patch */
 415
 416     if (result == -1 && errno == EINTR)
 417       goto again;
 418     else if (result < 1)
 419       {
 420       if (result == -1)
 421         log_write(0, LOG_MAIN|LOG_PANIC,
 422           "%s %s on spamd %s socket", loglabel, callout_address, strerror(errno));
 423       else
 424         {
 425         if (time(NULL) - start < sd->timeout)
 426           goto again;
 427         log_write(0, LOG_MAIN|LOG_PANIC,
 428           "%s timed out writing spamd %s, socket", loglabel, callout_address);
 429         }
 430       (void)close(spamd_cctx.sock);
 431       goto defer;
 432       }
 433
 434     wrote = send(spamd_cctx.sock,spamd_buffer + offset,read - offset,0);
 435     if (wrote == -1)
 436       {
 437       log_write(0, LOG_MAIN|LOG_PANIC,
 438           "%s %s on spamd %s socket", loglabel, callout_address, strerror(errno));
 439       (void)close(spamd_cctx.sock);
 440       goto defer;
 441       }
 442     if (offset + wrote != read)
 443       {
 444       offset += wrote;
 445       goto again;
 446       }
 447     }
 448   }
 449 while (!feof(mbox_file) && !ferror(mbox_file));
 450
 451 if (ferror(mbox_file))
 452   {
 453   log_write(0, LOG_MAIN|LOG_PANIC,
 454     "%s error reading spool file: %s", loglabel, strerror(errno));
 455   (void)close(spamd_cctx.sock);
 456   goto defer;
 457   }
 458
 459 (void)fclose(mbox_file);
 460
 461 /* we're done sending, close socket for writing */
 462 shutdown(spamd_cctx.sock, SHUT_WR);
 463
 464 /* read spamd response using what's left of the timeout.  */
 465 memset(spamd_buffer, 0, sizeof(spamd_buffer));
 466 offset = 0;
 467 while ((i = ip_recv(&spamd_cctx,
 468                    spamd_buffer + offset,
 469                    sizeof(spamd_buffer) - offset - 1,
 470                    sd->timeout - time(NULL) + start)) > 0)
 471   offset += i;
 472 spamd_buffer[offset] = '\0';    /* guard byte */
 473
 474 /* error handling */
 475 if (i <= 0 && errno != 0)
 476   {
 477   log_write(0, LOG_MAIN|LOG_PANIC,
 478        "%s error reading from spamd %s, socket: %s", loglabel, callout_address, strerror(errno));
 479   (void)close(spamd_cctx.sock);
 480   return DEFER;
 481   }
 482
 483 /* reading done */
 484 (void)close(spamd_cctx.sock);
 485
 486   {                             /* spamassassin */
 487   /* dig in the spamd output and put the report in a multiline header,
 488   if requested */
 489   if (sscanf(CS spamd_buffer,
 490        "SPAMD/%7s 0 EX_OK\r\nContent-length: %*u\r\n\r\n%lf/%lf\r\n%n",
 491        spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3)
 492     {
 493       /* try to fall back to pre-2.50 spamd output */
 494       if (sscanf(CS spamd_buffer,
 495            "SPAMD/%7s 0 EX_OK\r\nSpam: %*s ; %lf / %lf\r\n\r\n%n",
 496            spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3)
 497         {
 498         log_write(0, LOG_MAIN|LOG_PANIC,
 499                   "%s cannot parse spamd %s output", loglabel, callout_address);
 500         return DEFER;
 501         }
 502     }
 503
 504   spam_action_buffer = spamd_score >= spamd_threshold ? US"reject" : US"no action";
 505   }
 506
 507 /* Create report. Since this is a multiline string,
 508 we must hack it into shape first */
 509 p = &spamd_buffer[spamd_report_offset];
 510 q = spam_report_buffer;
 511 while (*p != '\0')
 512   {
 513   /* skip \r */
 514   if (*p == '\r')
 515     {
 516     p++;
 517     continue;
 518     }
 519   *q++ = *p;
 520   if (*p++ == '\n')
 521     {
 522     /* add an extra space after the newline to ensure
 523     that it is treated as a header continuation line */
 524     *q++ = ' ';
 525     }
 526   }
 527 /* NULL-terminate */
 528 *q-- = '\0';
 529 /* cut off trailing leftovers */
 530 while (*q <= ' ')
 531   *q-- = '\0';
 532
 533 spam_report = spam_report_buffer;
 534 spam_action = spam_action_buffer;
 535
 536 /* create spam bar */
 537 spamd_score_char = spamd_score > 0 ? '+' : '-';
 538 j = abs((int)(spamd_score));
 539 i = 0;
 540 if (j != 0)
 541   while ((i < j) && (i <= MAX_SPAM_BAR_CHARS))
 542      spam_bar_buffer[i++] = spamd_score_char;
 543 else
 544   {
 545   spam_bar_buffer[0] = '/';
 546   i = 1;
 547   }
 548 spam_bar_buffer[i] = '\0';
 549 spam_bar = spam_bar_buffer;
 550
 551 /* create "float" spam score */
 552 (void)string_format(spam_score_buffer, sizeof(spam_score_buffer),
 553         "%.1f", spamd_score);
 554 spam_score = spam_score_buffer;
 555
 556 /* create "int" spam score */
 557 j = (int)((spamd_score + 0.001)*10);
 558 (void)string_format(spam_score_int_buffer, sizeof(spam_score_int_buffer),
 559         "%d", j);
 560 spam_score_int = spam_score_int_buffer;
 561
 562 /* compare threshold against score */
 563 spam_rc = spamd_score >= spamd_threshold
 564   ? OK  /* spam as determined by user's threshold */
 565   : FAIL;       /* not spam */
 566
 567 /* remember expanded spamd_address if needed */
 568 if (spamd_address_work != spamd_address)
 569   prev_spamd_address_work = string_copy(spamd_address_work);
 570
 571 /* remember user name and "been here" for it */
 572 Ustrcpy(prev_user_name, user_name);
 573 spam_ok = 1;
 574
 575 return override
 576   ? OK          /* always return OK, no matter what the score */
 577   : spam_rc;
 578
 579 defer:
 580   (void)fclose(mbox_file);
 581   return DEFER;
 582 }
 583
 584 #endif
 585 /* vi: aw ai sw=2
 586 */