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[32];
  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_rspamd = FALSE;
  34 spamd->is_failed = FALSE;
  35 spamd->weight = SPAMD_WEIGHT;
  36 spamd->timeout = SPAMD_TIMEOUT;
  37 spamd->retry = 0;
  38 spamd->priority = 1;
  39 return 0;
  40 }
  41
  42
  43 static int
  44 spamd_param(const uschar * param, spamd_address_container * spamd)
  45 {
  46 static int timesinceday = -1;
  47 const uschar * s;
  48 const uschar * name;
  49
  50 /*XXX more clever parsing could discard embedded spaces? */
  51
  52 if (sscanf(CCS param, "pri=%u", &spamd->priority))
  53   return 0; /* OK */
  54
  55 if (sscanf(CCS param, "weight=%u", &spamd->weight))
  56   {
  57   if (spamd->weight == 0) /* this server disabled: skip it */
  58     return 1;
  59   return 0; /* OK */
  60   }
  61
  62 if (Ustrncmp(param, "time=", 5) == 0)
  63   {
  64   unsigned int start_h = 0, start_m = 0, start_s = 0;
  65   unsigned int end_h = 24, end_m = 0, end_s = 0;
  66   unsigned int time_start, time_end;
  67   const uschar * end_string;
  68
  69   name = US"time";
  70   s = param+5;
  71   if ((end_string = Ustrchr(s, '-')))
  72     {
  73     end_string++;
  74     if (  sscanf(CS end_string, "%u.%u.%u", &end_h,   &end_m,   &end_s)   == 0
  75        || sscanf(CS s,          "%u.%u.%u", &start_h, &start_m, &start_s) == 0
  76        )
  77       goto badval;
  78     }
  79   else
  80     goto badval;
  81
  82   if (timesinceday < 0)
  83     {
  84     time_t now = time(NULL);
  85     struct tm *tmp = localtime(&now);
  86     timesinceday = tmp->tm_hour*3600 + tmp->tm_min*60 + tmp->tm_sec;
  87     }
  88
  89   time_start = start_h*3600 + start_m*60 + start_s;
  90   time_end = end_h*3600 + end_m*60 + end_s;
  91
  92   if (timesinceday < time_start || timesinceday >= time_end)
  93     return 1; /* skip spamd server */
  94
  95   return 0; /* OK */
  96   }
  97
  98 if (Ustrcmp(param, "variant=rspamd") == 0)
  99   {
 100   spamd->is_rspamd = TRUE;
 101   return 0;
 102   }
 103
 104 if (Ustrncmp(param, "tmo=", 4) == 0)
 105   {
 106   int sec = readconf_readtime((s = param+4), '\0', FALSE);
 107   name = US"timeout";
 108   if (sec < 0)
 109     goto badval;
 110   spamd->timeout = sec;
 111   return 0;
 112   }
 113
 114 if (Ustrncmp(param, "retry=", 6) == 0)
 115   {
 116   int sec = readconf_readtime((s = param+6), '\0', FALSE);
 117   name = US"retry";
 118   if (sec < 0)
 119     goto badval;
 120   spamd->retry = sec;
 121   return 0;
 122   }
 123
 124 log_write(0, LOG_MAIN, "%s warning - invalid spamd parameter: '%s'",
 125   loglabel, param);
 126 return -1; /* syntax error */
 127
 128 badval:
 129   log_write(0, LOG_MAIN,
 130     "%s warning - invalid spamd %s value: '%s'", loglabel, name, s);
 131   return -1; /* syntax error */
 132 }
 133
 134
 135 static int
 136 spamd_get_server(spamd_address_container ** spamds, int num_servers)
 137 {
 138 unsigned int i;
 139 spamd_address_container * sd;
 140 long weights;
 141 unsigned pri;
 142 static BOOL srandomed = FALSE;
 143
 144 /* speedup, if we have only 1 server */
 145 if (num_servers == 1)
 146   return (spamds[0]->is_failed ? -1 : 0);
 147
 148 /* init ranmod */
 149 if (!srandomed)
 150   {
 151   struct timeval tv;
 152   gettimeofday(&tv, NULL);
 153   srandom((unsigned int)(tv.tv_usec/1000));
 154   srandomed = TRUE;
 155   }
 156
 157 /* scan for highest pri */
 158 for (pri = 0, i = 0; i < num_servers; i++)
 159   {
 160   sd = spamds[i];
 161   if (!sd->is_failed && sd->priority > pri) pri = sd->priority;
 162   }
 163
 164 /* get sum of weights */
 165 for (weights = 0, i = 0; i < num_servers; i++)
 166   {
 167   sd = spamds[i];
 168   if (!sd->is_failed && sd->priority == pri) weights += sd->weight;
 169   }
 170 if (weights == 0)       /* all servers failed */
 171   return -1;
 172
 173 for (long rnd = random() % weights, i = 0; i < num_servers; i++)
 174   {
 175   sd = spamds[i];
 176   if (!sd->is_failed && sd->priority == pri)
 177     if ((rnd -= sd->weight) <= 0)
 178       return i;
 179   }
 180
 181 log_write(0, LOG_MAIN|LOG_PANIC,
 182   "%s unknown error (memory/cpu corruption?)", loglabel);
 183 return -1;
 184 }
 185
 186
 187 int
 188 spam(const uschar **listptr)
 189 {
 190 int sep = 0;
 191 const uschar *list = *listptr;
 192 uschar *user_name;
 193 uschar user_name_buffer[128];
 194 unsigned long mbox_size;
 195 FILE *mbox_file;
 196 client_conn_ctx spamd_cctx = {.sock = -1};
 197 uschar spamd_buffer[32600];
 198 int i, j, offset, result;
 199 uschar spamd_version[8];
 200 uschar spamd_short_result[8];
 201 uschar spamd_score_char;
 202 double spamd_threshold, spamd_score, spamd_reject_score;
 203 int spamd_report_offset;
 204 uschar *p,*q;
 205 int override = 0;
 206 time_t start;
 207 size_t read, wrote;
 208 #ifndef NO_POLL_H
 209 struct pollfd pollfd;
 210 #else                               /* Patch posted by Erik ? for OS X */
 211 struct timeval select_tv;         /* and applied by PH */
 212 fd_set select_fd;
 213 #endif
 214 uschar *spamd_address_work;
 215 spamd_address_container * sd;
 216
 217 /* stop compiler warning */
 218 result = 0;
 219
 220 /* find the username from the option list */
 221 if ((user_name = string_nextinlist(&list, &sep,
 222                                    user_name_buffer,
 223                                    sizeof(user_name_buffer))) == NULL)
 224   {
 225   /* no username given, this means no scanning should be done */
 226   return FAIL;
 227   }
 228
 229 /* if username is "0" or "false", do not scan */
 230 if ( (Ustrcmp(user_name,"0") == 0) ||
 231      (strcmpic(user_name,US"false") == 0) )
 232   return FAIL;
 233
 234 /* if there is an additional option, check if it is "true" */
 235 if (strcmpic(list,US"true") == 0)
 236   /* in that case, always return true later */
 237   override = 1;
 238
 239 /* expand spamd_address if needed */
 240 if (*spamd_address == '$')
 241   {
 242   spamd_address_work = expand_string(spamd_address);
 243   if (spamd_address_work == NULL)
 244     {
 245     log_write(0, LOG_MAIN|LOG_PANIC,
 246       "%s spamd_address starts with $, but expansion failed: %s",
 247       loglabel, expand_string_message);
 248     return DEFER;
 249     }
 250   }
 251 else
 252   spamd_address_work = spamd_address;
 253
 254 DEBUG(D_acl) debug_printf_indent("spamd: addrlist '%s'\n", spamd_address_work);
 255
 256 /* check if previous spamd_address was expanded and has changed. dump cached results if so */
 257 if (  spam_ok
 258    && prev_spamd_address_work != NULL
 259    && Ustrcmp(prev_spamd_address_work, spamd_address_work) != 0
 260    )
 261   spam_ok = 0;
 262
 263 /* if we scanned for this username last time, just return */
 264 if (spam_ok && Ustrcmp(prev_user_name, user_name) == 0)
 265   return override ? OK : spam_rc;
 266
 267 /* make sure the eml mbox file is spooled up */
 268
 269 if (!(mbox_file = spool_mbox(&mbox_size, NULL, NULL)))
 270   {                                                             /* error while spooling */
 271   log_write(0, LOG_MAIN|LOG_PANIC,
 272          "%s error while creating mbox spool file", loglabel);
 273   return DEFER;
 274   }
 275
 276 start = time(NULL);
 277
 278   {
 279   int num_servers = 0;
 280   int current_server;
 281   uschar * address;
 282   const uschar * spamd_address_list_ptr = spamd_address_work;
 283   spamd_address_container * spamd_address_vector[32];
 284
 285   /* Check how many spamd servers we have
 286      and register their addresses */
 287   sep = 0;                              /* default colon-sep */
 288   while ((address = string_nextinlist(&spamd_address_list_ptr, &sep, NULL, 0)))
 289     {
 290     const uschar * sublist;
 291     int sublist_sep = -(int)' ';        /* default space-sep */
 292     unsigned args;
 293     uschar * s;
 294
 295     DEBUG(D_acl) debug_printf_indent("spamd: addr entry '%s'\n", address);
 296     sd = store_get(sizeof(spamd_address_container), FALSE);
 297
 298     for (sublist = address, args = 0, spamd_param_init(sd);
 299          (s = string_nextinlist(&sublist, &sublist_sep, NULL, 0));
 300          args++
 301          )
 302       {
 303         DEBUG(D_acl) debug_printf_indent("spamd:  addr parm '%s'\n", s);
 304         switch (args)
 305         {
 306         case 0:   sd->hostspec = s;
 307                   if (*s == '/') args++;        /* local; no port */
 308                   break;
 309         case 1:   sd->hostspec = string_sprintf("%s %s", sd->hostspec, s);
 310                   break;
 311         default:  spamd_param(s, sd);
 312                   break;
 313         }
 314       }
 315     if (args < 2)
 316       {
 317       log_write(0, LOG_MAIN,
 318         "%s warning - invalid spamd address: '%s'", loglabel, address);
 319       continue;
 320       }
 321
 322     spamd_address_vector[num_servers] = sd;
 323     if (++num_servers > 31)
 324       break;
 325     }
 326
 327   /* check if we have at least one server */
 328   if (!num_servers)
 329     {
 330     log_write(0, LOG_MAIN|LOG_PANIC,
 331        "%s no useable spamd server addresses in spamd_address configuration option.",
 332        loglabel);
 333     goto defer;
 334     }
 335
 336   current_server = spamd_get_server(spamd_address_vector, num_servers);
 337   sd = spamd_address_vector[current_server];
 338   for(;;)
 339     {
 340     uschar * errstr;
 341
 342     DEBUG(D_acl) debug_printf_indent("spamd: trying server %s\n", sd->hostspec);
 343
 344     for (;;)
 345       {
 346       /*XXX could potentially use TFO early-data here */
 347       if (  (spamd_cctx.sock = ip_streamsocket(sd->hostspec, &errstr, 5, NULL)) >= 0
 348          || sd->retry <= 0
 349          )
 350         break;
 351       DEBUG(D_acl) debug_printf_indent("spamd: server %s: retry conn\n", sd->hostspec);
 352       while (sd->retry > 0) sd->retry = sleep(sd->retry);
 353       }
 354     if (spamd_cctx.sock >= 0)
 355       break;
 356
 357     log_write(0, LOG_MAIN, "%s spamd: %s", loglabel, errstr);
 358     sd->is_failed = TRUE;
 359
 360     current_server = spamd_get_server(spamd_address_vector, num_servers);
 361     if (current_server < 0)
 362       {
 363       log_write(0, LOG_MAIN|LOG_PANIC, "%s all spamd servers failed", loglabel);
 364       goto defer;
 365       }
 366     sd = spamd_address_vector[current_server];
 367     }
 368   }
 369
 370 (void)fcntl(spamd_cctx.sock, F_SETFL, O_NONBLOCK);
 371 /* now we are connected to spamd on spamd_cctx.sock */
 372 if (sd->is_rspamd)
 373   {
 374   gstring * req_str;
 375   const uschar * s;
 376
 377   req_str = string_append(NULL, 8,
 378     "CHECK RSPAMC/1.3\r\nContent-length: ", string_sprintf("%lu\r\n", mbox_size),
 379     "Queue-Id: ", message_id,
 380     "\r\nFrom: <", sender_address,
 381     ">\r\nRecipient-Number: ", string_sprintf("%d\r\n", recipients_count));
 382
 383   for (int i = 0; i < recipients_count; i++)
 384     req_str = string_append(req_str, 3,
 385       "Rcpt: <", recipients_list[i].address, ">\r\n");
 386   if ((s = expand_string(US"$sender_helo_name")) && *s)
 387     req_str = string_append(req_str, 3, "Helo: ", s, "\r\n");
 388   if ((s = expand_string(US"$sender_host_name")) && *s)
 389     req_str = string_append(req_str, 3, "Hostname: ", s, "\r\n");
 390   if (sender_host_address)
 391     req_str = string_append(req_str, 3, "IP: ", sender_host_address, "\r\n");
 392   if ((s = expand_string(US"$authenticated_id")) && *s)
 393     req_str = string_append(req_str, 3, "User: ", s, "\r\n");
 394   req_str = string_catn(req_str, US"\r\n", 2);
 395   wrote = send(spamd_cctx.sock, req_str->s, req_str->ptr, 0);
 396   }
 397 else
 398   {                             /* spamassassin variant */
 399   (void)string_format(spamd_buffer,
 400           sizeof(spamd_buffer),
 401           "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
 402           user_name,
 403           mbox_size);
 404   /* send our request */
 405   wrote = send(spamd_cctx.sock, spamd_buffer, Ustrlen(spamd_buffer), 0);
 406   }
 407
 408 if (wrote == -1)
 409   {
 410   (void)close(spamd_cctx.sock);
 411   log_write(0, LOG_MAIN|LOG_PANIC,
 412        "%s spamd %s send failed: %s", loglabel, callout_address, strerror(errno));
 413   goto defer;
 414   }
 415
 416 /* now send the file */
 417 /* spamd sometimes accepts connections but doesn't read data off
 418  * the connection.  We make the file descriptor non-blocking so
 419  * that the write will only write sufficient data without blocking
 420  * and we poll the descriptor to make sure that we can write without
 421  * blocking.  Short writes are gracefully handled and if the whole
 422  * transaction takes too long it is aborted.
 423  * Note: poll() is not supported in OSX 10.2 and is reported to be
 424  *       broken in more recent versions (up to 10.4).
 425  */
 426 #ifndef NO_POLL_H
 427 pollfd.fd = spamd_cctx.sock;
 428 pollfd.events = POLLOUT;
 429 #endif
 430 (void)fcntl(spamd_cctx.sock, F_SETFL, O_NONBLOCK);
 431 do
 432   {
 433   read = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
 434   if (read > 0)
 435     {
 436     offset = 0;
 437 again:
 438 #ifndef NO_POLL_H
 439     result = poll(&pollfd, 1, 1000);
 440
 441 /* Patch posted by Erik ? for OS X and applied by PH */
 442 #else
 443     select_tv.tv_sec = 1;
 444     select_tv.tv_usec = 0;
 445     FD_ZERO(&select_fd);
 446     FD_SET(spamd_cctx.sock, &select_fd);
 447     result = select(spamd_cctx.sock+1, NULL, &select_fd, NULL, &select_tv);
 448 #endif
 449 /* End Erik's patch */
 450
 451     if (result == -1 && errno == EINTR)
 452       goto again;
 453     else if (result < 1)
 454       {
 455       if (result == -1)
 456         log_write(0, LOG_MAIN|LOG_PANIC,
 457           "%s %s on spamd %s socket", loglabel, callout_address, strerror(errno));
 458       else
 459         {
 460         if (time(NULL) - start < sd->timeout)
 461           goto again;
 462         log_write(0, LOG_MAIN|LOG_PANIC,
 463           "%s timed out writing spamd %s, socket", loglabel, callout_address);
 464         }
 465       (void)close(spamd_cctx.sock);
 466       goto defer;
 467       }
 468
 469     wrote = send(spamd_cctx.sock,spamd_buffer + offset,read - offset,0);
 470     if (wrote == -1)
 471       {
 472       log_write(0, LOG_MAIN|LOG_PANIC,
 473           "%s %s on spamd %s socket", loglabel, callout_address, strerror(errno));
 474       (void)close(spamd_cctx.sock);
 475       goto defer;
 476       }
 477     if (offset + wrote != read)
 478       {
 479       offset += wrote;
 480       goto again;
 481       }
 482     }
 483   }
 484 while (!feof(mbox_file) && !ferror(mbox_file));
 485
 486 if (ferror(mbox_file))
 487   {
 488   log_write(0, LOG_MAIN|LOG_PANIC,
 489     "%s error reading spool file: %s", loglabel, strerror(errno));
 490   (void)close(spamd_cctx.sock);
 491   goto defer;
 492   }
 493
 494 (void)fclose(mbox_file);
 495
 496 /* we're done sending, close socket for writing */
 497 if (!sd->is_rspamd)
 498   shutdown(spamd_cctx.sock,SHUT_WR);
 499
 500 /* read spamd response using what's left of the timeout.  */
 501 memset(spamd_buffer, 0, sizeof(spamd_buffer));
 502 offset = 0;
 503 while ((i = ip_recv(&spamd_cctx,
 504                    spamd_buffer + offset,
 505                    sizeof(spamd_buffer) - offset - 1,
 506                    sd->timeout + start)) > 0)
 507   offset += i;
 508 spamd_buffer[offset] = '\0';    /* guard byte */
 509
 510 /* error handling */
 511 if (i <= 0 && errno != 0)
 512   {
 513   log_write(0, LOG_MAIN|LOG_PANIC,
 514        "%s error reading from spamd %s, socket: %s", loglabel, callout_address, strerror(errno));
 515   (void)close(spamd_cctx.sock);
 516   return DEFER;
 517   }
 518
 519 /* reading done */
 520 (void)close(spamd_cctx.sock);
 521
 522 if (sd->is_rspamd)
 523   {                             /* rspamd variant of reply */
 524   int r;
 525   if (  (r = sscanf(CS spamd_buffer,
 526           "RSPAMD/%7s 0 EX_OK\r\nMetric: default; %7s %lf / %lf / %lf\r\n%n",
 527           spamd_version, spamd_short_result, &spamd_score, &spamd_threshold,
 528           &spamd_reject_score, &spamd_report_offset)) != 5
 529      || spamd_report_offset >= offset           /* verify within buffer */
 530      )
 531     {
 532     log_write(0, LOG_MAIN|LOG_PANIC,
 533               "%s cannot parse spamd %s, output: %d", loglabel, callout_address, r);
 534     return DEFER;
 535     }
 536   /* now parse action */
 537   p = &spamd_buffer[spamd_report_offset];
 538
 539   if (Ustrncmp(p, "Action: ", sizeof("Action: ") - 1) == 0)
 540     {
 541     p += sizeof("Action: ") - 1;
 542     q = &spam_action_buffer[0];
 543     while (*p && *p != '\r' && (q - spam_action_buffer) < sizeof(spam_action_buffer) - 1)
 544       *q++ = *p++;
 545     *q = '\0';
 546     }
 547   }
 548 else
 549   {                             /* spamassassin */
 550   /* dig in the spamd output and put the report in a multiline header,
 551   if requested */
 552   if (sscanf(CS spamd_buffer,
 553        "SPAMD/%7s 0 EX_OK\r\nContent-length: %*u\r\n\r\n%lf/%lf\r\n%n",
 554        spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3)
 555     {
 556       /* try to fall back to pre-2.50 spamd output */
 557       if (sscanf(CS spamd_buffer,
 558            "SPAMD/%7s 0 EX_OK\r\nSpam: %*s ; %lf / %lf\r\n\r\n%n",
 559            spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3)
 560         {
 561         log_write(0, LOG_MAIN|LOG_PANIC,
 562                   "%s cannot parse spamd %s output", loglabel, callout_address);
 563         return DEFER;
 564         }
 565     }
 566
 567   Ustrcpy(spam_action_buffer,
 568     spamd_score >= spamd_threshold ? US"reject" : US"no action");
 569   }
 570
 571 /* Create report. Since this is a multiline string,
 572 we must hack it into shape first */
 573 p = &spamd_buffer[spamd_report_offset];
 574 q = spam_report_buffer;
 575 while (*p != '\0')
 576   {
 577   /* skip \r */
 578   if (*p == '\r')
 579     {
 580     p++;
 581     continue;
 582     }
 583   *q++ = *p;
 584   if (*p++ == '\n')
 585     {
 586     /* add an extra space after the newline to ensure
 587     that it is treated as a header continuation line */
 588     *q++ = ' ';
 589     }
 590   }
 591 /* NULL-terminate */
 592 *q-- = '\0';
 593 /* cut off trailing leftovers */
 594 while (*q <= ' ')
 595   *q-- = '\0';
 596
 597 spam_report = spam_report_buffer;
 598 spam_action = spam_action_buffer;
 599
 600 /* create spam bar */
 601 spamd_score_char = spamd_score > 0 ? '+' : '-';
 602 j = abs((int)(spamd_score));
 603 i = 0;
 604 if (j != 0)
 605   while ((i < j) && (i <= MAX_SPAM_BAR_CHARS))
 606      spam_bar_buffer[i++] = spamd_score_char;
 607 else
 608   {
 609   spam_bar_buffer[0] = '/';
 610   i = 1;
 611   }
 612 spam_bar_buffer[i] = '\0';
 613 spam_bar = spam_bar_buffer;
 614
 615 /* create "float" spam score */
 616 (void)string_format(spam_score_buffer, sizeof(spam_score_buffer),
 617         "%.1f", spamd_score);
 618 spam_score = spam_score_buffer;
 619
 620 /* create "int" spam score */
 621 j = (int)((spamd_score + 0.001)*10);
 622 (void)string_format(spam_score_int_buffer, sizeof(spam_score_int_buffer),
 623         "%d", j);
 624 spam_score_int = spam_score_int_buffer;
 625
 626 /* compare threshold against score */
 627 spam_rc = spamd_score >= spamd_threshold
 628   ? OK  /* spam as determined by user's threshold */
 629   : FAIL;       /* not spam */
 630
 631 /* remember expanded spamd_address if needed */
 632 if (spamd_address_work != spamd_address)
 633   prev_spamd_address_work = string_copy(spamd_address_work);
 634
 635 /* remember user name and "been here" for it */
 636 Ustrcpy(prev_user_name, user_name);
 637 spam_ok = 1;
 638
 639 return override
 640   ? OK          /* always return OK, no matter what the score */
 641   : spam_rc;
 642
 643 defer:
 644   (void)fclose(mbox_file);
 645   return DEFER;
 646 }
 647
 648 #endif
 649 /* vi: aw ai sw=2
 650 */