src/src/dcc.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) Wolfgang Breyha 2005-2012
   6  * Vienna University Computer Center
   7  * wbreyha@gmx.net
   8  * See the file NOTICE for conditions of use and distribution.
   9  */
  10
  11 /* This patch is based on code from Tom Kistners exiscan (ACL integration) and
  12  * the DCC local_scan patch from Christopher Bodenstein */
  13
  14 /* Code for calling dccifd. Called from acl.c. */
  15
  16 #include "exim.h"
  17 #ifdef EXPERIMENTAL_DCC
  18 #include "dcc.h"
  19 #include "unistd.h"
  20
  21 uschar dcc_header_str[256];
  22 int dcc_ok = 0;
  23 int dcc_rc = 0;
  24
  25 /* This function takes a file descriptor and a buffer as input and
  26  * returns either 0 for success or errno in case of error. */
  27
  28 int flushbuffer (int socket, uschar *buffer)
  29  {
  30   int retval, rsp;
  31   rsp = write(socket, buffer, Ustrlen(buffer));
  32   DEBUG(D_acl)
  33     debug_printf("DCC: Result of the write() = %d\n", rsp);
  34   if(rsp < 0)
  35   {
  36     DEBUG(D_acl)
  37       debug_printf("DCC: Error writing buffer to socket: %s\n", strerror(errno));
  38     retval = errno;
  39   } else {
  40     DEBUG(D_acl)
  41       debug_printf("DCC: Wrote buffer to socket:\n%s\n", buffer);
  42     retval = 0;
  43   }
  44   return retval;
  45 }
  46
  47 int dcc_process(uschar **listptr) {
  48   int sep = 0;
  49   uschar *list = *listptr;
  50   FILE *data_file;
  51   uschar *dcc_daemon_ip = US"";
  52   uschar *dcc_default_ip_option = US"127.0.0.1";
  53   uschar *dcc_ip_option = US"";
  54   uschar *dcc_helo_option = US"localhost";
  55   uschar *dcc_reject_message = US"Rejected by DCC";
  56   uschar *xtra_hdrs = NULL;
  57
  58   /* from local_scan */
  59   int i, j, k, c, retval, sockfd, resp, line;
  60   unsigned int portnr;
  61   struct sockaddr_un  serv_addr;
  62   struct sockaddr_in  serv_addr_in;
  63   struct hostent *ipaddress;
  64   uschar sockpath[128];
  65   uschar sockip[40], client_ip[40];
  66   uschar opts[128];
  67   uschar rcpt[128], from[128];
  68   uschar sendbuf[4096];
  69   uschar recvbuf[4096];
  70   uschar dcc_return_text[1024];
  71   uschar mbox_path[1024];
  72   uschar message_subdir[2];
  73   struct header_line *dcchdr;
  74   uschar *dcc_acl_options;
  75   uschar dcc_acl_options_buffer[10];
  76   uschar dcc_xtra_hdrs[1024];
  77
  78   /* grep 1st option */
  79   if ((dcc_acl_options = string_nextinlist(&list, &sep,
  80                                            dcc_acl_options_buffer,
  81                                            sizeof(dcc_acl_options_buffer))) != NULL)
  82   {
  83     /* parse 1st option */
  84     if ( (strcmpic(dcc_acl_options,US"false") == 0) ||
  85          (Ustrcmp(dcc_acl_options,"0") == 0) ) {
  86       /* explicitly no matching */
  87       return FAIL;
  88     };
  89
  90     /* special cases (match anything except empty) */
  91     if ( (strcmpic(dcc_acl_options,US"true") == 0) ||
  92          (Ustrcmp(dcc_acl_options,"*") == 0) ||
  93          (Ustrcmp(dcc_acl_options,"1") == 0) ) {
  94       dcc_acl_options = dcc_acl_options;
  95     };
  96   }
  97   else {
  98     /* empty means "don't match anything" */
  99     return FAIL;
 100   };
 101
 102   sep = 0;
 103
 104   /* if we scanned this message last time, just return */
 105   if ( dcc_ok )
 106       return dcc_rc;
 107
 108   /* open the spooled body */
 109   message_subdir[1] = '\0';
 110   for (i = 0; i < 2; i++) {
 111     message_subdir[0] = (split_spool_directory == (i == 0))? message_id[5] : 0;
 112     sprintf(CS mbox_path, "%s/input/%s/%s-D", spool_directory, message_subdir, message_id);
 113     data_file = Ufopen(mbox_path,"rb");
 114     if (data_file != NULL)
 115       break;
 116   };
 117
 118   if (data_file == NULL) {
 119     /* error while spooling */
 120     log_write(0, LOG_MAIN|LOG_PANIC,
 121            "dcc acl condition: error while opening spool file");
 122     return DEFER;
 123   };
 124
 125   /* Initialize the variables */
 126
 127   bzero(sockip,sizeof(sockip));
 128   if (dccifd_address) {
 129     if (dccifd_address[0] == '/')
 130       Ustrncpy(sockpath, dccifd_address, sizeof(sockpath));
 131     else
 132       if( sscanf(CS dccifd_address, "%s %u", sockip, &portnr) != 2) {
 133         log_write(0, LOG_MAIN,
 134           "dcc acl condition: warning - invalid dccifd address: '%s'", dccifd_address);
 135         (void)fclose(data_file);
 136         return DEFER;
 137       }
 138   }
 139
 140   /* opts is what we send as dccifd options - see man dccifd */
 141   /* We don't support any other option than 'header' so just copy that */
 142   bzero(opts,sizeof(opts));
 143   Ustrncpy(opts, "header", sizeof(opts)-1);
 144   Ustrncpy(client_ip, dcc_ip_option, sizeof(client_ip)-1);
 145   /* If the dcc_client_ip is not provided use the
 146    * sender_host_address or 127.0.0.1 if it is NULL */
 147   DEBUG(D_acl)
 148     debug_printf("DCC: my_ip_option = %s - client_ip = %s - sender_host_address = %s\n", dcc_ip_option, client_ip, sender_host_address);
 149   if(!(Ustrcmp(client_ip, ""))){
 150     /* Do we have a sender_host_address or is it NULL? */
 151     if(sender_host_address){
 152       Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
 153     } else {
 154       /* sender_host_address is NULL which means it comes from localhost */
 155       Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
 156     }
 157   }
 158   DEBUG(D_acl)
 159     debug_printf("DCC: Client IP: %s\n", client_ip);
 160   Ustrncpy(sockip, dcc_daemon_ip, sizeof(sockip)-1);
 161   /* strncat(opts, my_request, strlen(my_request)); */
 162   Ustrcat(opts, "\n");
 163   Ustrncat(opts, client_ip, sizeof(opts)-Ustrlen(opts)-1);
 164   Ustrncat(opts, "\nHELO ", sizeof(opts)-Ustrlen(opts)-1);
 165   Ustrncat(opts, dcc_helo_option, sizeof(opts)-Ustrlen(opts)-2);
 166   Ustrcat(opts, "\n");
 167
 168   /* initialize the other variables */
 169   dcchdr = header_list;
 170   /* we set the default return value to DEFER */
 171   retval = DEFER;
 172
 173   bzero(sendbuf,sizeof(sendbuf));
 174   bzero(dcc_header_str,sizeof(dcc_header_str));
 175   bzero(rcpt,sizeof(rcpt));
 176   bzero(from,sizeof(from));
 177
 178   /* send a null return path as "<>". */
 179   if (Ustrlen(sender_address) > 0)
 180     Ustrncpy(from, sender_address, sizeof(from));
 181   else
 182     Ustrncpy(from, "<>", sizeof(from));
 183   Ustrncat(from, "\n", sizeof(from)-Ustrlen(from)-1);
 184
 185   /**************************************
 186    * Now creating the socket connection *
 187    **************************************/
 188
 189   /* If there is a dcc_daemon_ip, we use a tcp socket, otherwise a UNIX socket */
 190   if(Ustrcmp(sockip, "")){
 191     ipaddress = gethostbyname((char *)sockip);
 192     bzero((char *) &serv_addr_in, sizeof(serv_addr_in));
 193     serv_addr_in.sin_family = AF_INET;
 194     bcopy((char *)ipaddress->h_addr, (char *)&serv_addr_in.sin_addr.s_addr, ipaddress->h_length);
 195     serv_addr_in.sin_port = htons(portnr);
 196     if ((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){
 197       DEBUG(D_acl)
 198         debug_printf("DCC: Creating TCP socket connection failed: %s\n", strerror(errno));
 199       log_write(0,LOG_PANIC,"DCC: Creating TCP socket connection failed: %s\n", strerror(errno));
 200       /* if we cannot create the socket, defer the mail */
 201       (void)fclose(data_file);
 202       return retval;
 203     }
 204     /* Now connecting the socket (INET) */
 205     if (connect(sockfd, (struct sockaddr *)&serv_addr_in, sizeof(serv_addr_in)) < 0){
 206       DEBUG(D_acl)
 207         debug_printf("DCC: Connecting to TCP socket failed: %s\n", strerror(errno));
 208       log_write(0,LOG_PANIC,"DCC: Connecting to TCP socket failed: %s\n", strerror(errno));
 209       /* if we cannot contact the socket, defer the mail */
 210       (void)fclose(data_file);
 211       return retval;
 212     }
 213   } else {
 214     /* connecting to the dccifd UNIX socket */
 215     bzero((char *)&serv_addr,sizeof(serv_addr));
 216     serv_addr.sun_family = AF_UNIX;
 217     Ustrcpy(serv_addr.sun_path, sockpath);
 218     if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0){
 219       DEBUG(D_acl)
 220         debug_printf("DCC: Creating UNIX socket connection failed: %s\n", strerror(errno));
 221       log_write(0,LOG_PANIC,"DCC: Creating UNIX socket connection failed: %s\n", strerror(errno));
 222       /* if we cannot create the socket, defer the mail */
 223       (void)fclose(data_file);
 224       return retval;
 225     }
 226     /* Now connecting the socket (UNIX) */
 227     if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0){
 228       DEBUG(D_acl)
 229                             debug_printf("DCC: Connecting to UNIX socket failed: %s\n", strerror(errno));
 230       log_write(0,LOG_PANIC,"DCC: Connecting to UNIX socket failed: %s\n", strerror(errno));
 231       /* if we cannot contact the socket, defer the mail */
 232       (void)fclose(data_file);
 233       return retval;
 234     }
 235   }
 236   /* the socket is open, now send the options to dccifd*/
 237   DEBUG(D_acl)
 238     debug_printf("\nDCC: ---------------------------\nDCC: Socket opened; now sending input\nDCC: -----------------\n");
 239   /* First, fill in the input buffer */
 240   Ustrncpy(sendbuf, opts, sizeof(sendbuf));
 241   Ustrncat(sendbuf, from, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 242
 243   DEBUG(D_acl)
 244   {
 245     debug_printf("DCC: opts = %s\nDCC: sender = %s\nDCC: rcpt count = %d\n", opts, from, recipients_count);
 246     debug_printf("DCC: Sending options:\nDCC: ****************************\n");
 247   }
 248
 249   /* let's send each of the recipients to dccifd */
 250   for (i = 0; i < recipients_count; i++){
 251     DEBUG(D_acl)
 252       debug_printf("DCC: recipient = %s\n",recipients_list[i].address);
 253     if(Ustrlen(sendbuf) + Ustrlen(recipients_list[i].address) > sizeof(sendbuf))
 254     {
 255       DEBUG(D_acl)
 256         debug_printf("DCC: Writing buffer: %s\n", sendbuf);
 257       flushbuffer(sockfd, sendbuf);
 258       bzero(sendbuf, sizeof(sendbuf));
 259     }
 260     Ustrncat(sendbuf, recipients_list[i].address, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 261     Ustrncat(sendbuf, "\r\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 262   }
 263   /* send a blank line between options and message */
 264   Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 265   /* Now we send the input buffer */
 266   DEBUG(D_acl)
 267     debug_printf("DCC: %s\nDCC: ****************************\n", sendbuf);
 268   flushbuffer(sockfd, sendbuf);
 269
 270   /* now send the message */
 271   /* Clear the input buffer */
 272   bzero(sendbuf, sizeof(sendbuf));
 273   /* First send the headers */
 274   /* Now send the headers */
 275   DEBUG(D_acl)
 276     debug_printf("DCC: Sending headers:\nDCC: ****************************\n");
 277   Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
 278   while((dcchdr=dcchdr->next)) {
 279     if(dcchdr->slen > sizeof(sendbuf)-2) {
 280       /* The size of the header is bigger than the size of
 281        * the input buffer, so split it up in smaller parts. */
 282        flushbuffer(sockfd, sendbuf);
 283        bzero(sendbuf, sizeof(sendbuf));
 284        j = 0;
 285        while(j < dcchdr->slen)
 286        {
 287         for(i = 0; i < sizeof(sendbuf)-2; i++) {
 288           sendbuf[i] = dcchdr->text[j];
 289           j++;
 290         }
 291         flushbuffer(sockfd, sendbuf);
 292         bzero(sendbuf, sizeof(sendbuf));
 293        }
 294     } else if(Ustrlen(sendbuf) + dcchdr->slen > sizeof(sendbuf)-2) {
 295       flushbuffer(sockfd, sendbuf);
 296       bzero(sendbuf, sizeof(sendbuf));
 297       Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
 298     } else {
 299       Ustrncat(sendbuf, dcchdr->text, sizeof(sendbuf)-Ustrlen(sendbuf)-2);
 300     }
 301   }
 302
 303   /* a blank line seperates header from body */
 304   Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 305   flushbuffer(sockfd, sendbuf);
 306   DEBUG(D_acl)
 307     debug_printf("\nDCC: ****************************\n%s", sendbuf);
 308
 309   /* Clear the input buffer */
 310   bzero(sendbuf, sizeof(sendbuf));
 311
 312   /* now send the body */
 313   DEBUG(D_acl)
 314     debug_printf("DCC: Writing body:\nDCC: ****************************\n");
 315   (void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);
 316   while((fread(sendbuf, 1, sizeof(sendbuf)-1, data_file)) > 0) {
 317     flushbuffer(sockfd, sendbuf);
 318     bzero(sendbuf, sizeof(sendbuf));
 319   }
 320   DEBUG(D_acl)
 321     debug_printf("\nDCC: ****************************\n");
 322
 323   /* shutdown() the socket */
 324   if(shutdown(sockfd, 1) < 0){
 325     DEBUG(D_acl)
 326       debug_printf("DCC: Couldn't shutdown socket: %s\n", strerror(errno));
 327     log_write(0,LOG_MAIN,"DCC: Couldn't shutdown socket: %s\n", strerror(errno));
 328     /* If there is a problem with the shutdown()
 329      * defer the mail. */
 330     (void)fclose(data_file);
 331     return retval;
 332   }
 333   DEBUG(D_acl)
 334     debug_printf("\nDCC: -------------------------\nDCC: Input sent.\nDCC: -------------------------\n");
 335
 336     /********************************
 337    * receiving output from dccifd *
 338    ********************************/
 339   DEBUG(D_acl)
 340     debug_printf("\nDCC: -------------------------------------\nDCC: Now receiving output from server\nDCC: -----------------------------------\n");
 341
 342   /******************************************************************
 343    * We should get 3 lines:                                         *
 344    * 1/ First line is overall result: either 'A' for Accept,        *
 345    *    'R' for Reject, 'S' for accept Some recipients or           *
 346    *    'T' for a Temporary error.                                  *
 347    * 2/ Second line contains the list of Accepted/Rejected          *
 348    *    recipients in the form AARRA (A = accepted, R = rejected).  *
 349    * 3/ Third line contains the X-DCC header.                       *
 350    ******************************************************************/
 351
 352   line = 1;    /* we start at the first line of the output */
 353   j = 0;       /* will be used as index for the recipients list */
 354   k = 0;       /* initializing the index of the X-DCC header: dcc_header_str[k] */
 355
 356   /* Let's read from the socket until there's nothing left to read */
 357   bzero(recvbuf, sizeof(recvbuf));
 358   while((resp = read(sockfd, recvbuf, sizeof(recvbuf)-1)) > 0) {
 359     /* How much did we get from the socket */
 360     c = Ustrlen(recvbuf) + 1;
 361     DEBUG(D_acl)
 362       debug_printf("DCC: Length of the output buffer is: %d\nDCC: Output buffer is:\nDCC: ------------\nDCC: %s\nDCC: -----------\n", c, recvbuf);
 363
 364     /* Now let's read each character and see what we've got */
 365     for(i = 0; i < c; i++) {
 366       /* First check if we reached the end of the line and
 367        * then increment the line counter */
 368       if(recvbuf[i] == '\n') {
 369         line++;
 370       }
 371       else {
 372         /* The first character of the first line is the
 373          * overall response. If there's another character
 374          * on that line it is not correct. */
 375         if(line == 1) {
 376           if(i == 0) {
 377             /* Now get the value and set the
 378              * return value accordingly */
 379             if(recvbuf[i] == 'A') {
 380               DEBUG(D_acl)
 381                 debug_printf("DCC: Overall result = A\treturning OK\n");
 382               Ustrcpy(dcc_return_text, "Mail accepted by DCC");
 383               dcc_result = US"A";
 384               retval = OK;
 385             }
 386             else if(recvbuf[i] == 'R') {
 387               DEBUG(D_acl)
 388                 debug_printf("DCC: Overall result = R\treturning FAIL\n");
 389               dcc_result = US"R";
 390               retval = FAIL;
 391               if(sender_host_name) {
 392                 log_write(0, LOG_MAIN, "H=%s [%s] F=<%s>: rejected by DCC", sender_host_name, sender_host_address, sender_address);
 393               }
 394               else {
 395                 log_write(0, LOG_MAIN, "H=[%s] F=<%s>: rejected by DCC", sender_host_address, sender_address);
 396               }
 397               Ustrncpy(dcc_return_text, dcc_reject_message, Ustrlen(dcc_reject_message) + 1);
 398             }
 399             else if(recvbuf[i] == 'S') {
 400               DEBUG(D_acl)
 401                 debug_printf("DCC: Overall result  = S\treturning OK\n");
 402               Ustrcpy(dcc_return_text, "Not all recipients accepted by DCC");
 403               /* Since we're in an ACL we want a global result
 404                * so we accept for all */
 405               dcc_result = US"A";
 406               retval = OK;
 407             }
 408             else if(recvbuf[i] == 'G') {
 409               DEBUG(D_acl)
 410                 debug_printf("DCC: Overall result  = G\treturning FAIL\n");
 411               Ustrcpy(dcc_return_text, "Greylisted by DCC");
 412               dcc_result = US"G";
 413               retval = FAIL;
 414             }
 415             else if(recvbuf[i] == 'T') {
 416               DEBUG(D_acl)
 417                 debug_printf("DCC: Overall result = T\treturning DEFER\n");
 418               retval = DEFER;
 419               log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", recvbuf);
 420               Ustrcpy(dcc_return_text, "Temporary error with DCC");
 421               dcc_result = US"T";
 422             }
 423             else {
 424               DEBUG(D_acl)
 425                 debug_printf("DCC: Overall result = something else\treturning DEFER\n");
 426               retval = DEFER;
 427               log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", recvbuf);
 428               Ustrcpy(dcc_return_text, "Unknown DCC response");
 429               dcc_result = US"T";
 430             }
 431           }
 432           else {
 433           /* We're on the first line but not on the first character,
 434            * there must be something wrong. */
 435             DEBUG(D_acl)
 436               debug_printf("DCC: Line = %d but i = %d != 0  character is %c - This is wrong!\n", line, i, recvbuf[i]);
 437               log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", recvbuf);
 438           }
 439         }
 440         else if(line == 2) {
 441           /* On the second line we get a list of
 442            * answers for each recipient. We don't care about
 443            * it because we're in an acl and take the
 444            * global result. */
 445         }
 446         else if(line > 2) {
 447           /* The third and following lines are the X-DCC header,
 448            * so we store it in dcc_header_str. */
 449           /* check if we don't get more than we can handle */
 450           if(k < sizeof(dcc_header_str)) {
 451             dcc_header_str[k] = recvbuf[i];
 452             k++;
 453           }
 454           else {
 455             DEBUG(D_acl)
 456               debug_printf("DCC: We got more output than we can store in the X-DCC header. Truncating at 120 characters.\n");
 457           }
 458         }
 459         else {
 460           /* Wrong line number. There must be a problem with the output. */
 461           DEBUG(D_acl)
 462             debug_printf("DCC: Wrong line number in output. Line number is %d\n", line);
 463         }
 464       }
 465     }
 466     /* we reinitialize the output buffer before we read again */
 467     bzero(recvbuf,sizeof(recvbuf));
 468   }
 469   /* We have read everything from the socket */
 470
 471   /* We need to terminate the X-DCC header with a '\n' character. This needs to be k-1
 472    * since dcc_header_str[k] contains '\0'. */
 473   dcc_header_str[k-1] = '\n';
 474
 475   /* Now let's sum up what we've got. */
 476   DEBUG(D_acl)
 477     debug_printf("\nDCC: --------------------------\nDCC: Overall result = %d\nDCC: X-DCC header: %sReturn message: %s\nDCC: dcc_result: %s\n", retval, dcc_header_str, dcc_return_text, dcc_result);
 478
 479   /* We only add the X-DCC header if it starts with X-DCC */
 480   if(!(Ustrncmp(dcc_header_str, "X-DCC", 5))){
 481     dcc_header = dcc_header_str;
 482     if(dcc_direct_add_header) {
 483       header_add(' ' , "%s", dcc_header_str);
 484   /* since the MIME ACL already writes the .eml file to disk without DCC Header we've to erase it */
 485       unspool_mbox();
 486     }
 487   }
 488   else {
 489     DEBUG(D_acl)
 490       debug_printf("DCC: Wrong format of the X-DCC header: %s\n", dcc_header_str);
 491   }
 492
 493   /* check if we should add additional headers passed in acl_m_dcc_add_header */
 494   if(dcc_direct_add_header) {
 495     if (((xtra_hdrs = expand_string(US"$acl_m_dcc_add_header")) != NULL) && (xtra_hdrs[0] != '\0')) {
 496       Ustrncpy(dcc_xtra_hdrs, xtra_hdrs, sizeof(dcc_xtra_hdrs) - 2);
 497       if (dcc_xtra_hdrs[Ustrlen(dcc_xtra_hdrs)-1] != '\n')
 498         Ustrcat(dcc_xtra_hdrs, "\n");
 499       header_add(' ', "%s", dcc_xtra_hdrs);
 500       DEBUG(D_acl)
 501         debug_printf("DCC: adding additional headers in $acl_m_dcc_add_header: %s", dcc_xtra_hdrs);
 502     }
 503   }
 504
 505   dcc_ok = 1;
 506   /* Now return to exim main process */
 507   DEBUG(D_acl)
 508     debug_printf("DCC: Before returning to exim main process:\nDCC: return_text = %s - retval = %d\nDCC: dcc_result = %s\n", dcc_return_text, retval, dcc_result);
 509
 510   (void)fclose(data_file);
 511   dcc_rc = retval;
 512   return dcc_rc;
 513 }
 514
 515 #endif