src/src/spam.c

   1 /* $Cambridge: exim/src/src/spam.c,v 1.11 2005/08/01 14:41:25 ph10 Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2003-???? */
   8 /* License: GPL */
   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_report_buffer[32600];
  20 uschar prev_user_name[128] = "";
  21 int spam_ok = 0;
  22 int spam_rc = 0;
  23
  24 int spam(uschar **listptr) {
  25   int sep = 0;
  26   uschar *list = *listptr;
  27   uschar *user_name;
  28   uschar user_name_buffer[128];
  29   unsigned long mbox_size;
  30   FILE *mbox_file;
  31   int spamd_sock;
  32   uschar spamd_buffer[32600];
  33   int i, j, offset, result;
  34   uschar spamd_version[8];
  35   uschar spamd_score_char;
  36   double spamd_threshold, spamd_score;
  37   int spamd_report_offset;
  38   uschar *p,*q;
  39   int override = 0;
  40   time_t start;
  41   size_t read, wrote;
  42   struct sockaddr_un server;
  43 #ifndef NO_POLL_H
  44   struct pollfd pollfd;
  45 #endif
  46
  47   /* stop compiler warning */
  48   result = result;
  49
  50   /* find the username from the option list */
  51   if ((user_name = string_nextinlist(&list, &sep,
  52                                      user_name_buffer,
  53                                      sizeof(user_name_buffer))) == NULL) {
  54     /* no username given, this means no scanning should be done */
  55     return FAIL;
  56   };
  57
  58   /* if username is "0" or "false", do not scan */
  59   if ( (Ustrcmp(user_name,"0") == 0) ||
  60        (strcmpic(user_name,US"false") == 0) ) {
  61     return FAIL;
  62   };
  63
  64   /* if there is an additional option, check if it is "true" */
  65   if (strcmpic(list,US"true") == 0) {
  66     /* in that case, always return true later */
  67     override = 1;
  68   };
  69
  70   /* if we scanned for this username last time, just return */
  71   if ( spam_ok && ( Ustrcmp(prev_user_name, user_name) == 0 ) ) {
  72     if (override)
  73       return OK;
  74     else
  75       return spam_rc;
  76   };
  77
  78   /* make sure the eml mbox file is spooled up */
  79   mbox_file = spool_mbox(&mbox_size);
  80
  81   if (mbox_file == NULL) {
  82     /* error while spooling */
  83     log_write(0, LOG_MAIN|LOG_PANIC,
  84            "spam acl condition: error while creating mbox spool file");
  85     return DEFER;
  86   };
  87
  88   start = time(NULL);
  89   /* socket does not start with '/' -> network socket */
  90   if (*spamd_address != '/') {
  91     time_t now = time(NULL);
  92     int num_servers = 0;
  93     int current_server = 0;
  94     int start_server = 0;
  95     uschar *address = NULL;
  96     uschar *spamd_address_list_ptr = spamd_address;
  97     uschar address_buffer[256];
  98     spamd_address_container * spamd_address_vector[32];
  99
 100     /* Check how many spamd servers we have
 101        and register their addresses */
 102     while ((address = string_nextinlist(&spamd_address_list_ptr, &sep,
 103                                         address_buffer,
 104                                         sizeof(address_buffer))) != NULL) {
 105
 106       spamd_address_container *this_spamd =
 107         (spamd_address_container *)store_get(sizeof(spamd_address_container));
 108
 109       /* grok spamd address and port */
 110       if( sscanf(CS address, "%s %u", this_spamd->tcp_addr, &(this_spamd->tcp_port)) != 2 ) {
 111         log_write(0, LOG_MAIN,
 112           "spam acl condition: warning - invalid spamd address: '%s'", address);
 113         continue;
 114       };
 115
 116       spamd_address_vector[num_servers] = this_spamd;
 117       num_servers++;
 118       if (num_servers > 31)
 119         break;
 120     };
 121
 122     /* check if we have at least one server */
 123     if (!num_servers) {
 124       log_write(0, LOG_MAIN|LOG_PANIC,
 125          "spam acl condition: no useable spamd server addresses in spamd_address configuration option.");
 126       (void)fclose(mbox_file);
 127       return DEFER;
 128     };
 129
 130     current_server = start_server = (int)now % num_servers;
 131
 132     while (1) {
 133
 134       debug_printf("trying server %s, port %u\n",
 135                    spamd_address_vector[current_server]->tcp_addr,
 136                    spamd_address_vector[current_server]->tcp_port);
 137
 138       /* contact a spamd */
 139       if ( (spamd_sock = ip_socket(SOCK_STREAM, AF_INET)) < 0) {
 140         log_write(0, LOG_MAIN|LOG_PANIC,
 141            "spam acl condition: error creating IP socket for spamd");
 142         (void)fclose(mbox_file);
 143         return DEFER;
 144       };
 145
 146       if (ip_connect( spamd_sock,
 147                       AF_INET,
 148                       spamd_address_vector[current_server]->tcp_addr,
 149                       spamd_address_vector[current_server]->tcp_port,
 150                       5 ) > -1) {
 151         /* connection OK */
 152         break;
 153       };
 154
 155       log_write(0, LOG_MAIN|LOG_PANIC,
 156          "spam acl condition: warning - spamd connection to %s, port %u failed: %s",
 157          spamd_address_vector[current_server]->tcp_addr,
 158          spamd_address_vector[current_server]->tcp_port,
 159          strerror(errno));
 160       current_server++;
 161       if (current_server >= num_servers)
 162         current_server = 0;
 163       if (current_server == start_server) {
 164         log_write(0, LOG_MAIN|LOG_PANIC, "spam acl condition: all spamd servers failed");
 165         (void)fclose(mbox_file);
 166         (void)close(spamd_sock);
 167         return DEFER;
 168       };
 169     };
 170
 171   }
 172   else {
 173     /* open the local socket */
 174
 175     if ((spamd_sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 176       log_write(0, LOG_MAIN|LOG_PANIC,
 177                 "malware acl condition: spamd: unable to acquire socket (%s)",
 178                 strerror(errno));
 179       (void)fclose(mbox_file);
 180       return DEFER;
 181     }
 182
 183     server.sun_family = AF_UNIX;
 184     Ustrcpy(server.sun_path, spamd_address);
 185
 186     if (connect(spamd_sock, (struct sockaddr *) &server, sizeof(struct sockaddr_un)) < 0) {
 187       log_write(0, LOG_MAIN|LOG_PANIC,
 188                 "malware acl condition: spamd: unable to connect to UNIX socket %s (%s)",
 189                 spamd_address, strerror(errno) );
 190       (void)fclose(mbox_file);
 191       (void)close(spamd_sock);
 192       return DEFER;
 193     }
 194
 195   }
 196
 197   /* now we are connected to spamd on spamd_sock */
 198   (void)string_format(spamd_buffer,
 199            sizeof(spamd_buffer),
 200            "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
 201            user_name,
 202            mbox_size);
 203
 204   /* send our request */
 205   if (send(spamd_sock, spamd_buffer, Ustrlen(spamd_buffer), 0) < 0) {
 206     (void)close(spamd_sock);
 207     log_write(0, LOG_MAIN|LOG_PANIC,
 208          "spam acl condition: spamd send failed: %s", strerror(errno));
 209     (void)fclose(mbox_file);
 210     (void)close(spamd_sock);
 211     return DEFER;
 212   };
 213
 214   /* now send the file */
 215   /* spamd sometimes accepts conections but doesn't read data off
 216    * the connection.  We make the file descriptor non-blocking so
 217    * that the write will only write sufficient data without blocking
 218    * and we poll the desciptor to make sure that we can write without
 219    * blocking.  Short writes are gracefully handled and if the whole
 220    * trasaction takes too long it is aborted.
 221    * Note: poll() is not supported in OSX 10.2.
 222    */
 223 #ifndef NO_POLL_H
 224   pollfd.fd = spamd_sock;
 225   pollfd.events = POLLOUT;
 226 #endif
 227   (void)fcntl(spamd_sock, F_SETFL, O_NONBLOCK);
 228   do {
 229     read = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
 230     if (read > 0) {
 231       offset = 0;
 232 again:
 233 #ifndef NO_POLL_H
 234       result = poll(&pollfd, 1, 1000);
 235       if (result == -1 && errno == EINTR)
 236         continue;
 237       else if (result < 1) {
 238         if (result == -1)
 239           log_write(0, LOG_MAIN|LOG_PANIC,
 240             "spam acl condition: %s on spamd socket", strerror(errno));
 241         else {
 242           if (time(NULL) - start < SPAMD_TIMEOUT)
 243           goto again;
 244           log_write(0, LOG_MAIN|LOG_PANIC,
 245             "spam acl condition: timed out writing spamd socket");
 246         }
 247         (void)close(spamd_sock);
 248         (void)fclose(mbox_file);
 249         return DEFER;
 250       }
 251 #endif
 252       wrote = send(spamd_sock,spamd_buffer + offset,read - offset,0);
 253       if (wrote == -1)
 254       {
 255           log_write(0, LOG_MAIN|LOG_PANIC,
 256             "spam acl condition: %s on spamd socket", strerror(errno));
 257         (void)close(spamd_sock);
 258         (void)fclose(mbox_file);
 259         return DEFER;
 260       }
 261       if (offset + wrote != read) {
 262         offset += wrote;
 263         goto again;
 264       }
 265     }
 266   }
 267   while (!feof(mbox_file) && !ferror(mbox_file));
 268   if (ferror(mbox_file)) {
 269     log_write(0, LOG_MAIN|LOG_PANIC,
 270       "spam acl condition: error reading spool file: %s", strerror(errno));
 271     (void)close(spamd_sock);
 272     (void)fclose(mbox_file);
 273     return DEFER;
 274   }
 275
 276   (void)fclose(mbox_file);
 277
 278   /* we're done sending, close socket for writing */
 279   shutdown(spamd_sock,SHUT_WR);
 280
 281   /* read spamd response using what's left of the timeout.
 282    */
 283   memset(spamd_buffer, 0, sizeof(spamd_buffer));
 284   offset = 0;
 285   while((i = ip_recv(spamd_sock,
 286                      spamd_buffer + offset,
 287                      sizeof(spamd_buffer) - offset - 1,
 288                      SPAMD_TIMEOUT - time(NULL) + start)) > 0 ) {
 289     offset += i;
 290   }
 291
 292   /* error handling */
 293   if((i <= 0) && (errno != 0)) {
 294     log_write(0, LOG_MAIN|LOG_PANIC,
 295          "spam acl condition: error reading from spamd socket: %s", strerror(errno));
 296     (void)close(spamd_sock);
 297     return DEFER;
 298   }
 299
 300   /* reading done */
 301   (void)close(spamd_sock);
 302
 303   /* dig in the spamd output and put the report in a multiline header, if requested */
 304   if( sscanf(CS spamd_buffer,"SPAMD/%s 0 EX_OK\r\nContent-length: %*u\r\n\r\n%lf/%lf\r\n%n",
 305              spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
 306
 307     /* try to fall back to pre-2.50 spamd output */
 308     if( sscanf(CS spamd_buffer,"SPAMD/%s 0 EX_OK\r\nSpam: %*s ; %lf / %lf\r\n\r\n%n",
 309                spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
 310       log_write(0, LOG_MAIN|LOG_PANIC,
 311          "spam acl condition: cannot parse spamd output");
 312       return DEFER;
 313     };
 314   };
 315
 316   /* Create report. Since this is a multiline string,
 317   we must hack it into shape first */
 318   p = &spamd_buffer[spamd_report_offset];
 319   q = spam_report_buffer;
 320   while (*p != '\0') {
 321     /* skip \r */
 322     if (*p == '\r') {
 323       p++;
 324       continue;
 325     };
 326     *q = *p;
 327     q++;
 328     if (*p == '\n') {
 329       *q = '\t';
 330       q++;
 331       /* eat whitespace */
 332       while( (*p <= ' ') && (*p != '\0') ) {
 333         p++;
 334       };
 335       p--;
 336     };
 337     p++;
 338   };
 339   /* NULL-terminate */
 340   *q = '\0';
 341   q--;
 342   /* cut off trailing leftovers */
 343   while (*q <= ' ') {
 344     *q = '\0';
 345     q--;
 346   };
 347   spam_report = spam_report_buffer;
 348
 349   /* create spam bar */
 350   spamd_score_char = spamd_score > 0 ? '+' : '-';
 351   j = abs((int)(spamd_score));
 352   i = 0;
 353   if( j != 0 ) {
 354     while((i < j) && (i <= MAX_SPAM_BAR_CHARS))
 355        spam_bar_buffer[i++] = spamd_score_char;
 356   }
 357   else{
 358     spam_bar_buffer[0] = '/';
 359     i = 1;
 360   }
 361   spam_bar_buffer[i] = '\0';
 362   spam_bar = spam_bar_buffer;
 363
 364   /* create "float" spam score */
 365   (void)string_format(spam_score_buffer, sizeof(spam_score_buffer),"%.1f", spamd_score);
 366   spam_score = spam_score_buffer;
 367
 368   /* create "int" spam score */
 369   j = (int)((spamd_score + 0.001)*10);
 370   (void)string_format(spam_score_int_buffer, sizeof(spam_score_int_buffer), "%d", j);
 371   spam_score_int = spam_score_int_buffer;
 372
 373   /* compare threshold against score */
 374   if (spamd_score >= spamd_threshold) {
 375     /* spam as determined by user's threshold */
 376     spam_rc = OK;
 377   }
 378   else {
 379     /* not spam */
 380     spam_rc = FAIL;
 381   };
 382
 383   /* remember user name and "been here" for it */
 384   Ustrcpy(prev_user_name, user_name);
 385   spam_ok = 1;
 386
 387   if (override) {
 388     /* always return OK, no matter what the score */
 389     return OK;
 390   }
 391   else {
 392     return spam_rc;
 393   };
 394 }
 395
 396 #endif