src/src/spam.c

   1 /* $Cambridge: exim/src/src/spam.c,v 1.7 2005/06/10 13:29:36 tom 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   /* find the username from the option list */
  48   if ((user_name = string_nextinlist(&list, &sep,
  49                                      user_name_buffer,
  50                                      sizeof(user_name_buffer))) == NULL) {
  51     /* no username given, this means no scanning should be done */
  52     return FAIL;
  53   };
  54
  55   /* if username is "0" or "false", do not scan */
  56   if ( (Ustrcmp(user_name,"0") == 0) ||
  57        (strcmpic(user_name,US"false") == 0) ) {
  58     return FAIL;
  59   };
  60
  61   /* if there is an additional option, check if it is "true" */
  62   if (strcmpic(list,US"true") == 0) {
  63     /* in that case, always return true later */
  64     override = 1;
  65   };
  66
  67   /* if we scanned for this username last time, just return */
  68   if ( spam_ok && ( Ustrcmp(prev_user_name, user_name) == 0 ) ) {
  69     if (override)
  70       return OK;
  71     else
  72       return spam_rc;
  73   };
  74
  75   /* make sure the eml mbox file is spooled up */
  76   mbox_file = spool_mbox(&mbox_size);
  77
  78   if (mbox_file == NULL) {
  79     /* error while spooling */
  80     log_write(0, LOG_MAIN|LOG_PANIC,
  81            "spam acl condition: error while creating mbox spool file");
  82     return DEFER;
  83   };
  84
  85   start = time(NULL);
  86   /* socket does not start with '/' -> network socket */
  87   if (*spamd_address != '/') {
  88     time_t now = time(NULL);
  89     int num_servers = 0;
  90     int current_server = 0;
  91     int start_server = 0;
  92     uschar *address = NULL;
  93     uschar *spamd_address_list_ptr = spamd_address;
  94     uschar address_buffer[256];
  95     spamd_address_container * spamd_address_vector[32];
  96
  97     /* Check how many spamd servers we have
  98        and register their addresses */
  99     while ((address = string_nextinlist(&spamd_address_list_ptr, &sep,
 100                                         address_buffer,
 101                                         sizeof(address_buffer))) != NULL) {
 102
 103       spamd_address_container *this_spamd =
 104         (spamd_address_container *)store_get(sizeof(spamd_address_container));
 105
 106       /* grok spamd address and port */
 107       if( sscanf(CS address, "%s %u", this_spamd->tcp_addr, &(this_spamd->tcp_port)) != 2 ) {
 108         log_write(0, LOG_MAIN,
 109           "spam acl condition: warning - invalid spamd address: '%s'", address);
 110         continue;
 111       };
 112
 113       spamd_address_vector[num_servers] = this_spamd;
 114       num_servers++;
 115       if (num_servers > 31)
 116         break;
 117     };
 118
 119     /* check if we have at least one server */
 120     if (!num_servers) {
 121       log_write(0, LOG_MAIN|LOG_PANIC,
 122          "spam acl condition: no useable spamd server addresses in spamd_address configuration option.");
 123       fclose(mbox_file);
 124       return DEFER;
 125     };
 126
 127     current_server = start_server = (int)now % num_servers;
 128
 129     while (1) {
 130
 131       debug_printf("trying server %s, port %u\n",
 132                    spamd_address_vector[current_server]->tcp_addr,
 133                    spamd_address_vector[current_server]->tcp_port);
 134
 135       /* contact a spamd */
 136       if ( (spamd_sock = ip_socket(SOCK_STREAM, AF_INET)) < 0) {
 137         log_write(0, LOG_MAIN|LOG_PANIC,
 138            "spam acl condition: error creating IP socket for spamd");
 139         fclose(mbox_file);
 140         return DEFER;
 141       };
 142
 143       if (ip_connect( spamd_sock,
 144                       AF_INET,
 145                       spamd_address_vector[current_server]->tcp_addr,
 146                       spamd_address_vector[current_server]->tcp_port,
 147                       5 ) > -1) {
 148         /* connection OK */
 149         break;
 150       };
 151
 152       log_write(0, LOG_MAIN|LOG_PANIC,
 153          "spam acl condition: warning - spamd connection to %s, port %u failed: %s",
 154          spamd_address_vector[current_server]->tcp_addr,
 155          spamd_address_vector[current_server]->tcp_port,
 156          strerror(errno));
 157       current_server++;
 158       if (current_server >= num_servers)
 159         current_server = 0;
 160       if (current_server == start_server) {
 161         log_write(0, LOG_MAIN|LOG_PANIC, "spam acl condition: all spamd servers failed");
 162         fclose(mbox_file);
 163         close(spamd_sock);
 164         return DEFER;
 165       };
 166     };
 167
 168   }
 169   else {
 170     /* open the local socket */
 171
 172     if ((spamd_sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 173       log_write(0, LOG_MAIN|LOG_PANIC,
 174                 "malware acl condition: spamd: unable to acquire socket (%s)",
 175                 strerror(errno));
 176       fclose(mbox_file);
 177       return DEFER;
 178     }
 179
 180     server.sun_family = AF_UNIX;
 181     Ustrcpy(server.sun_path, spamd_address);
 182
 183     if (connect(spamd_sock, (struct sockaddr *) &server, sizeof(struct sockaddr_un)) < 0) {
 184       log_write(0, LOG_MAIN|LOG_PANIC,
 185                 "malware acl condition: spamd: unable to connect to UNIX socket %s (%s)",
 186                 spamd_address, strerror(errno) );
 187       fclose(mbox_file);
 188       close(spamd_sock);
 189       return DEFER;
 190     }
 191
 192   }
 193
 194   /* now we are connected to spamd on spamd_sock */
 195   snprintf(CS spamd_buffer,
 196            sizeof(spamd_buffer),
 197            "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
 198            user_name,
 199            mbox_size);
 200
 201   /* send our request */
 202   if (send(spamd_sock, spamd_buffer, Ustrlen(spamd_buffer), 0) < 0) {
 203     close(spamd_sock);
 204     log_write(0, LOG_MAIN|LOG_PANIC,
 205          "spam acl condition: spamd send failed: %s", strerror(errno));
 206     fclose(mbox_file);
 207     close(spamd_sock);
 208     return DEFER;
 209   };
 210
 211   /* now send the file */
 212   /* spamd sometimes accepts conections but doesn't read data off
 213    * the connection.  We make the file descriptor non-blocking so
 214    * that the write will only write sufficient data without blocking
 215    * and we poll the desciptor to make sure that we can write without
 216    * blocking.  Short writes are gracefully handled and if the whole
 217    * trasaction takes too long it is aborted.
 218    * Note: poll() is not supported in OSX 10.2.
 219    */
 220 #ifndef NO_POLL_H
 221   pollfd.fd = spamd_sock;
 222   pollfd.events = POLLOUT;
 223 #endif
 224   fcntl(spamd_sock, F_SETFL, O_NONBLOCK);
 225   do {
 226     read = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
 227     if (read > 0) {
 228       offset = 0;
 229 again:
 230 #ifndef NO_POLL_H
 231       result = poll(&pollfd, 1, 1000);
 232       if (result == -1 && errno == EINTR)
 233         continue;
 234       else if (result < 1) {
 235         if (result == -1)
 236           log_write(0, LOG_MAIN|LOG_PANIC,
 237             "spam acl condition: %s on spamd socket", strerror(errno));
 238         else {
 239           if (time(NULL) - start < SPAMD_TIMEOUT)
 240           goto again;
 241           log_write(0, LOG_MAIN|LOG_PANIC,
 242             "spam acl condition: timed out writing spamd socket");
 243         }
 244         close(spamd_sock);
 245         fclose(mbox_file);
 246         return DEFER;
 247       }
 248 #endif
 249       wrote = send(spamd_sock,spamd_buffer + offset,read - offset,0);
 250       if (wrote == -1)
 251       {
 252           log_write(0, LOG_MAIN|LOG_PANIC,
 253             "spam acl condition: %s on spamd socket", strerror(errno));
 254         close(spamd_sock);
 255         fclose(mbox_file);
 256         return DEFER;
 257       }
 258       if (offset + wrote != read) {
 259         offset += wrote;
 260         goto again;
 261       }
 262     }
 263   }
 264   while (!feof(mbox_file) && !ferror(mbox_file));
 265   if (ferror(mbox_file)) {
 266     log_write(0, LOG_MAIN|LOG_PANIC,
 267       "spam acl condition: error reading spool file: %s", strerror(errno));
 268     close(spamd_sock);
 269     fclose(mbox_file);
 270     return DEFER;
 271   }
 272
 273   fclose(mbox_file);
 274
 275   /* we're done sending, close socket for writing */
 276   shutdown(spamd_sock,SHUT_WR);
 277
 278   /* read spamd response using what's left of the timeout.
 279    */
 280   memset(spamd_buffer, 0, sizeof(spamd_buffer));
 281   offset = 0;
 282   while((i = ip_recv(spamd_sock,
 283                      spamd_buffer + offset,
 284                      sizeof(spamd_buffer) - offset - 1,
 285                      SPAMD_TIMEOUT - time(NULL) + start)) > 0 ) {
 286     offset += i;
 287   }
 288
 289   /* error handling */
 290   if((i <= 0) && (errno != 0)) {
 291     log_write(0, LOG_MAIN|LOG_PANIC,
 292          "spam acl condition: error reading from spamd socket: %s", strerror(errno));
 293     close(spamd_sock);
 294     return DEFER;
 295   }
 296
 297   /* reading done */
 298   close(spamd_sock);
 299
 300   /* dig in the spamd output and put the report in a multiline header, if requested */
 301   if( sscanf(CS spamd_buffer,"SPAMD/%s 0 EX_OK\r\nContent-length: %*u\r\n\r\n%lf/%lf\r\n%n",
 302              spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
 303
 304     /* try to fall back to pre-2.50 spamd output */
 305     if( sscanf(CS spamd_buffer,"SPAMD/%s 0 EX_OK\r\nSpam: %*s ; %lf / %lf\r\n\r\n%n",
 306                spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
 307       log_write(0, LOG_MAIN|LOG_PANIC,
 308          "spam acl condition: cannot parse spamd output");
 309       return DEFER;
 310     };
 311   };
 312
 313   /* Create report. Since this is a multiline string,
 314   we must hack it into shape first */
 315   p = &spamd_buffer[spamd_report_offset];
 316   q = spam_report_buffer;
 317   while (*p != '\0') {
 318     /* skip \r */
 319     if (*p == '\r') {
 320       p++;
 321       continue;
 322     };
 323     *q = *p;
 324     q++;
 325     if (*p == '\n') {
 326       *q = '\t';
 327       q++;
 328       /* eat whitespace */
 329       while( (*p <= ' ') && (*p != '\0') ) {
 330         p++;
 331       };
 332       p--;
 333     };
 334     p++;
 335   };
 336   /* NULL-terminate */
 337   *q = '\0';
 338   q--;
 339   /* cut off trailing leftovers */
 340   while (*q <= ' ') {
 341     *q = '\0';
 342     q--;
 343   };
 344   spam_report = spam_report_buffer;
 345
 346   /* create spam bar */
 347   spamd_score_char = spamd_score > 0 ? '+' : '-';
 348   j = abs((int)(spamd_score));
 349   i = 0;
 350   if( j != 0 ) {
 351     while((i < j) && (i <= MAX_SPAM_BAR_CHARS))
 352        spam_bar_buffer[i++] = spamd_score_char;
 353   }
 354   else{
 355     spam_bar_buffer[0] = '/';
 356     i = 1;
 357   }
 358   spam_bar_buffer[i] = '\0';
 359   spam_bar = spam_bar_buffer;
 360
 361   /* create "float" spam score */
 362   snprintf(CS spam_score_buffer, sizeof(spam_score_buffer),"%.1f", spamd_score);
 363   spam_score = spam_score_buffer;
 364
 365   /* create "int" spam score */
 366   j = (int)((spamd_score + 0.001)*10);
 367   snprintf(CS spam_score_int_buffer, sizeof(spam_score_int_buffer), "%d", j);
 368   spam_score_int = spam_score_int_buffer;
 369
 370   /* compare threshold against score */
 371   if (spamd_score >= spamd_threshold) {
 372     /* spam as determined by user's threshold */
 373     spam_rc = OK;
 374   }
 375   else {
 376     /* not spam */
 377     spam_rc = FAIL;
 378   };
 379
 380   /* remember user name and "been here" for it */
 381   Ustrcpy(prev_user_name, user_name);
 382   spam_ok = 1;
 383
 384   if (override) {
 385     /* always return OK, no matter what the score */
 386     return OK;
 387   }
 388   else {
 389     return spam_rc;
 390   };
 391 }
 392
 393 #endif