src/src/spam.c

   1 /* $Cambridge: exim/src/src/spam.c,v 1.3 2004/12/17 14:52:44 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;
  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   struct sockaddr_un server;
  41
  42   /* find the username from the option list */
  43   if ((user_name = string_nextinlist(&list, &sep,
  44                                      user_name_buffer,
  45                                      sizeof(user_name_buffer))) == NULL) {
  46     /* no username given, this means no scanning should be done */
  47     return FAIL;
  48   };
  49
  50   /* if username is "0" or "false", do not scan */
  51   if ( (Ustrcmp(user_name,"0") == 0) ||
  52        (strcmpic(user_name,US"false") == 0) ) {
  53     return FAIL;
  54   };
  55
  56   /* if there is an additional option, check if it is "true" */
  57   if (strcmpic(list,US"true") == 0) {
  58     /* in that case, always return true later */
  59     override = 1;
  60   };
  61
  62   /* if we scanned for this username last time, just return */
  63   if ( spam_ok && ( Ustrcmp(prev_user_name, user_name) == 0 ) ) {
  64     if (override)
  65       return OK;
  66     else
  67       return spam_rc;
  68   };
  69
  70   /* make sure the eml mbox file is spooled up */
  71   mbox_file = spool_mbox(&mbox_size);
  72
  73   if (mbox_file == NULL) {
  74     /* error while spooling */
  75     log_write(0, LOG_MAIN|LOG_PANIC,
  76            "spam acl condition: error while creating mbox spool file");
  77     return DEFER;
  78   };
  79
  80   /* socket does not start with '/' -> network socket */
  81   if (*spamd_address != '/') {
  82     time_t now = time(NULL);
  83     int num_servers = 0;
  84     int current_server = 0;
  85     int start_server = 0;
  86     uschar *address = NULL;
  87     uschar *spamd_address_list_ptr = spamd_address;
  88     uschar address_buffer[256];
  89     spamd_address_container * spamd_address_vector[32];
  90
  91     /* Check how many spamd servers we have
  92        and register their addresses */
  93     while ((address = string_nextinlist(&spamd_address_list_ptr, &sep,
  94                                         address_buffer,
  95                                         sizeof(address_buffer))) != NULL) {
  96
  97       spamd_address_container *this_spamd =
  98         (spamd_address_container *)store_get(sizeof(spamd_address_container));
  99
 100       /* grok spamd address and port */
 101       if( sscanf(CS address, "%s %u", this_spamd->tcp_addr, &(this_spamd->tcp_port)) != 2 ) {
 102         log_write(0, LOG_MAIN,
 103           "spam acl condition: warning - invalid spamd address: '%s'", address);
 104         continue;
 105       };
 106
 107       spamd_address_vector[num_servers] = this_spamd;
 108       num_servers++;
 109       if (num_servers > 31)
 110         break;
 111     };
 112
 113     /* check if we have at least one server */
 114     if (!num_servers) {
 115       log_write(0, LOG_MAIN|LOG_PANIC,
 116          "spam acl condition: no useable spamd server addresses in spamd_address configuration option.");
 117       fclose(mbox_file);
 118       return DEFER;
 119     };
 120
 121     current_server = start_server = (int)now % num_servers;
 122
 123     while (1) {
 124
 125       debug_printf("trying server %s, port %u\n",
 126                    spamd_address_vector[current_server]->tcp_addr,
 127                    spamd_address_vector[current_server]->tcp_port);
 128
 129       /* contact a spamd */
 130       if ( (spamd_sock = ip_socket(SOCK_STREAM, AF_INET)) < 0) {
 131         log_write(0, LOG_MAIN|LOG_PANIC,
 132            "spam acl condition: error creating IP socket for spamd");
 133         fclose(mbox_file);
 134         return DEFER;
 135       };
 136
 137       if (ip_connect( spamd_sock,
 138                       AF_INET,
 139                       spamd_address_vector[current_server]->tcp_addr,
 140                       spamd_address_vector[current_server]->tcp_port,
 141                       5 ) > -1) {
 142         /* connection OK */
 143         break;
 144       };
 145
 146       log_write(0, LOG_MAIN|LOG_PANIC,
 147          "spam acl condition: warning - spamd connection to %s, port %u failed: %s",
 148          spamd_address_vector[current_server]->tcp_addr,
 149          spamd_address_vector[current_server]->tcp_port,
 150          strerror(errno));
 151       current_server++;
 152       if (current_server >= num_servers)
 153         current_server = 0;
 154       if (current_server == start_server) {
 155         log_write(0, LOG_MAIN|LOG_PANIC, "spam acl condition: all spamd servers failed");
 156         fclose(mbox_file);
 157         close(spamd_sock);
 158         return DEFER;
 159       };
 160     };
 161
 162   }
 163   else {
 164     /* open the local socket */
 165
 166     if ((spamd_sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 167       log_write(0, LOG_MAIN|LOG_PANIC,
 168                 "malware acl condition: spamd: unable to acquire socket (%s)",
 169                 strerror(errno));
 170       fclose(mbox_file);
 171       return DEFER;
 172     }
 173
 174     server.sun_family = AF_UNIX;
 175     Ustrcpy(server.sun_path, spamd_address);
 176
 177     if (connect(spamd_sock, (struct sockaddr *) &server, sizeof(struct sockaddr_un)) < 0) {
 178       log_write(0, LOG_MAIN|LOG_PANIC,
 179                 "malware acl condition: spamd: unable to connect to UNIX socket %s (%s)",
 180                 spamd_address, strerror(errno) );
 181       fclose(mbox_file);
 182       close(spamd_sock);
 183       return DEFER;
 184     }
 185
 186   }
 187
 188   /* now we are connected to spamd on spamd_sock */
 189   snprintf(CS spamd_buffer,
 190            sizeof(spamd_buffer),
 191            "REPORT SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
 192            user_name,
 193            mbox_size);
 194
 195   /* send our request */
 196   if (send(spamd_sock, spamd_buffer, Ustrlen(spamd_buffer), 0) < 0) {
 197     close(spamd_sock);
 198     log_write(0, LOG_MAIN|LOG_PANIC,
 199          "spam acl condition: spamd send failed: %s", strerror(errno));
 200     fclose(mbox_file);
 201     close(spamd_sock);
 202     return DEFER;
 203   };
 204
 205   /* now send the file */
 206   do {
 207     j = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
 208     if (j > 0) {
 209       i = send(spamd_sock,spamd_buffer,j,0);
 210       if (i != j) {
 211         log_write(0, LOG_MAIN|LOG_PANIC,
 212           "spam acl condition: error/short send to spamd");
 213         close(spamd_sock);
 214         fclose(mbox_file);
 215         return DEFER;
 216       };
 217     };
 218   }
 219   while (j > 0);
 220
 221   fclose(mbox_file);
 222
 223   /* we're done sending, close socket for writing */
 224   shutdown(spamd_sock,SHUT_WR);
 225
 226   /* read spamd response */
 227   memset(spamd_buffer, 0, sizeof(spamd_buffer));
 228   offset = 0;
 229   while((i = ip_recv(spamd_sock,
 230                      spamd_buffer + offset,
 231                      sizeof(spamd_buffer) - offset - 1,
 232                      SPAMD_READ_TIMEOUT)) > 0 ) {
 233     offset += i;
 234   }
 235
 236   /* error handling */
 237   if((i <= 0) && (errno != 0)) {
 238     log_write(0, LOG_MAIN|LOG_PANIC,
 239          "spam acl condition: error reading from spamd socket: %s", strerror(errno));
 240     close(spamd_sock);
 241     return DEFER;
 242   }
 243
 244   /* reading done */
 245   close(spamd_sock);
 246
 247   /* dig in the spamd output and put the report in a multiline header, if requested */
 248   if( sscanf(CS spamd_buffer,"SPAMD/%s 0 EX_OK\r\nContent-length: %*u\r\n\r\n%lf/%lf\r\n%n",
 249              spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
 250
 251     /* try to fall back to pre-2.50 spamd output */
 252     if( sscanf(CS spamd_buffer,"SPAMD/%s 0 EX_OK\r\nSpam: %*s ; %lf / %lf\r\n\r\n%n",
 253                spamd_version,&spamd_score,&spamd_threshold,&spamd_report_offset) != 3 ) {
 254       log_write(0, LOG_MAIN|LOG_PANIC,
 255          "spam acl condition: cannot parse spamd output");
 256       return DEFER;
 257     };
 258   };
 259
 260   /* Create report. Since this is a multiline string,
 261   we must hack it into shape first */
 262   p = &spamd_buffer[spamd_report_offset];
 263   q = spam_report_buffer;
 264   while (*p != '\0') {
 265     /* skip \r */
 266     if (*p == '\r') {
 267       p++;
 268       continue;
 269     };
 270     *q = *p;
 271     q++;
 272     if (*p == '\n') {
 273       *q = '\t';
 274       q++;
 275       /* eat whitespace */
 276       while( (*p <= ' ') && (*p != '\0') ) {
 277         p++;
 278       };
 279       p--;
 280     };
 281     p++;
 282   };
 283   /* NULL-terminate */
 284   *q = '\0';
 285   q--;
 286   /* cut off trailing leftovers */
 287   while (*q <= ' ') {
 288     *q = '\0';
 289     q--;
 290   };
 291   spam_report = spam_report_buffer;
 292
 293   /* create spam bar */
 294   spamd_score_char = spamd_score > 0 ? '+' : '-';
 295   j = abs((int)(spamd_score));
 296   i = 0;
 297   if( j != 0 ) {
 298     while((i < j) && (i <= MAX_SPAM_BAR_CHARS))
 299        spam_bar_buffer[i++] = spamd_score_char;
 300   }
 301   else{
 302     spam_bar_buffer[0] = '/';
 303     i = 1;
 304   }
 305   spam_bar_buffer[i] = '\0';
 306   spam_bar = spam_bar_buffer;
 307
 308   /* create "float" spam score */
 309   snprintf(CS spam_score_buffer, sizeof(spam_score_buffer),"%.1f", spamd_score);
 310   spam_score = spam_score_buffer;
 311
 312   /* create "int" spam score */
 313   j = (int)((spamd_score + 0.001)*10);
 314   snprintf(CS spam_score_int_buffer, sizeof(spam_score_int_buffer), "%d", j);
 315   spam_score_int = spam_score_int_buffer;
 316
 317   /* compare threshold against score */
 318   if (spamd_score >= spamd_threshold) {
 319     /* spam as determined by user's threshold */
 320     spam_rc = OK;
 321   }
 322   else {
 323     /* not spam */
 324     spam_rc = FAIL;
 325   };
 326
 327   /* remember user name and "been here" for it */
 328   Ustrcpy(prev_user_name, user_name);
 329   spam_ok = 1;
 330
 331   if (override) {
 332     /* always return OK, no matter what the score */
 333     return OK;
 334   }
 335   else {
 336     return spam_rc;
 337   };
 338 }
 339
 340 #endif