src/src/dcc.c

   1 /* $Cambridge: exim/src/src/dcc.c,v 1.4 2009/11/11 10:08:01 nm4 Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) Wolfgang Breyha 2005-2009
   8  * Vienna University Computer Center
   9  * wbreyha@gmx.net
  10  * See the file NOTICE for conditions of use and distribution.
  11  */
  12
  13 /* This patch is based on code from Tom Kistners exiscan (ACL integration) and
  14  * the DCC local_scan patch from Christopher Bodenstein */
  15
  16 /* Code for calling dccifd. Called from acl.c. */
  17
  18 #include "exim.h"
  19 #ifdef EXPERIMENTAL_DCC
  20 #include "dcc.h"
  21 #include "unistd.h"
  22
  23 uschar dcc_header_str[256];
  24 uschar dcc_result_str[256];
  25 int dcc_ok = 0;
  26 int dcc_rc = 0;
  27
  28 /* This function takes a file descriptor and a buffer as input and
  29  * returns either 0 for success or errno in case of error. */
  30
  31 int flushbuffer (int socket, uschar *buffer)
  32  {
  33   int retval, rsp;
  34   rsp = write(socket, buffer, Ustrlen(buffer));
  35   DEBUG(D_acl)
  36     debug_printf("Result of the write() = %d\n", rsp);
  37   if(rsp < 0)
  38   {
  39     DEBUG(D_acl)
  40       debug_printf("Error writing buffer to socket: %s\n", strerror(errno));
  41     retval = errno;
  42   } else {
  43     DEBUG(D_acl)
  44       debug_printf("Wrote buffer to socket:\n%s\n", buffer);
  45     retval = 0;
  46   }
  47   return retval;
  48 }
  49
  50 int dcc_process(uschar **listptr) {
  51   int sep = 0;
  52   uschar *list = *listptr;
  53   FILE *data_file;
  54   uschar *dcc_daemon_ip = US"";
  55   uschar *dcc_default_ip_option = US"127.0.0.1";
  56   uschar *dcc_ip_option = US"";
  57   uschar *dcc_helo_option = US"localhost";
  58   uschar *dcc_reject_message = US"Rejected by DCC";
  59   uschar *xtra_hdrs = NULL;
  60
  61   /* from local_scan */
  62   int i, j, k, c, retval, sockfd, servlen, resp, line;
  63   unsigned int portnr;
  64   struct sockaddr_un  serv_addr;
  65   struct sockaddr_in  serv_addr_in;
  66   struct hostent *ipaddress;
  67   uschar sockpath[128];
  68   uschar sockip[40], client_ip[40];
  69   uschar opts[128];
  70   uschar rcpt[128], from[128];
  71   uschar sendbuf[4096];
  72   uschar recvbuf[4096];
  73   uschar xhdr[256];
  74   uschar dcc_return_text[1024];
  75   uschar mbox_path[1024];
  76   uschar message_subdir[2];
  77   struct header_line *dcchdr;
  78   uschar *dcc_acl_options;
  79   uschar dcc_acl_options_buffer[10];
  80   uschar dcc_xtra_hdrs[1024];
  81
  82   /* grep 1st option */
  83   if ((dcc_acl_options = string_nextinlist(&list, &sep,
  84                                            dcc_acl_options_buffer,
  85                                            sizeof(dcc_acl_options_buffer))) != NULL)
  86   {
  87     /* parse 1st option */
  88     if ( (strcmpic(dcc_acl_options,US"false") == 0) ||
  89          (Ustrcmp(dcc_acl_options,"0") == 0) ) {
  90       /* explicitly no matching */
  91       return FAIL;
  92     };
  93
  94     /* special cases (match anything except empty) */
  95     if ( (strcmpic(dcc_acl_options,US"true") == 0) ||
  96          (Ustrcmp(dcc_acl_options,"*") == 0) ||
  97          (Ustrcmp(dcc_acl_options,"1") == 0) ) {
  98       dcc_acl_options = dcc_acl_options;
  99     };
 100   }
 101   else {
 102     /* empty means "don't match anything" */
 103     return FAIL;
 104   };
 105
 106   sep = 0;
 107
 108   /* if we scanned this message last time, just return */
 109   if ( dcc_ok )
 110       return dcc_rc;
 111
 112   /* open the spooled body */
 113   message_subdir[1] = '\0';
 114   for (i = 0; i < 2; i++) {
 115     message_subdir[0] = (split_spool_directory == (i == 0))? message_id[5] : 0;
 116     sprintf(CS mbox_path, "%s/input/%s/%s-D", spool_directory, message_subdir, message_id);
 117     data_file = Ufopen(mbox_path,"rb");
 118     if (data_file != NULL)
 119       break;
 120   };
 121
 122   if (data_file == NULL) {
 123     /* error while spooling */
 124     log_write(0, LOG_MAIN|LOG_PANIC,
 125            "dcc acl condition: error while opening spool file");
 126     return DEFER;
 127   };
 128
 129   /* Initialize the variables */
 130
 131   bzero(sockip,sizeof(sockip));
 132   if (dccifd_address) {
 133     if (dccifd_address[0] == '/')
 134       Ustrncpy(sockpath, dccifd_address, sizeof(sockpath));
 135     else
 136       if( sscanf(CS dccifd_address, "%s %u", sockip, &portnr) != 2) {
 137         log_write(0, LOG_MAIN,
 138           "dcc acl condition: warning - invalid dccifd address: '%s'", dccifd_address);
 139         (void)fclose(data_file);
 140         return DEFER;
 141       }
 142   }
 143
 144   /* opts is what we send as dccifd options - see man dccifd */
 145   /* We don't support any other option than 'header' so just copy that */
 146   bzero(opts,sizeof(opts));
 147   Ustrncpy(opts, "header", sizeof(opts)-1);
 148   Ustrncpy(client_ip, dcc_ip_option, sizeof(client_ip)-1);
 149   /* If the dcc_client_ip is not provided use the
 150    * sender_host_address or 127.0.0.1 if it is NULL */
 151   DEBUG(D_acl)
 152     debug_printf("my_ip_option = %s - client_ip = %s - sender_host_address = %s\n", dcc_ip_option, client_ip, sender_host_address);
 153   if(!(Ustrcmp(client_ip, ""))){
 154     /* Do we have a sender_host_address or is it NULL? */
 155     if(sender_host_address){
 156       Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
 157     } else {
 158       /* sender_host_address is NULL which means it comes from localhost */
 159       Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
 160     }
 161   }
 162   DEBUG(D_acl)
 163     debug_printf("Client IP: %s\n", client_ip);
 164   Ustrncpy(sockip, dcc_daemon_ip, sizeof(sockip)-1);
 165   /* strncat(opts, my_request, strlen(my_request)); */
 166   Ustrcat(opts, "\n");
 167   Ustrncat(opts, client_ip, sizeof(opts)-Ustrlen(opts)-1);
 168   Ustrncat(opts, "\nHELO ", sizeof(opts)-Ustrlen(opts)-1);
 169   Ustrncat(opts, dcc_helo_option, sizeof(opts)-Ustrlen(opts)-2);
 170   Ustrcat(opts, "\n");
 171
 172   /* initialize the other variables */
 173   dcchdr = header_list;
 174   /* we set the default return value to DEFER */
 175   retval = DEFER;
 176
 177   bzero(sendbuf,sizeof(sendbuf));
 178   bzero(xhdr,sizeof(xhdr));
 179   bzero(rcpt,sizeof(rcpt));
 180   bzero(from,sizeof(from));
 181
 182   /* send a null return path as "<>". */
 183   if (Ustrlen(sender_address) > 0)
 184     Ustrncpy(from, sender_address, sizeof(from));
 185   else
 186     Ustrncpy(from, "<>", sizeof(from));
 187   Ustrncat(from, "\n", sizeof(from)-Ustrlen(from)-1);
 188
 189   /**************************************
 190    * Now creating the socket connection *
 191    **************************************/
 192
 193   /* If there is a dcc_daemon_ip, we use a tcp socket, otherwise a UNIX socket */
 194   if(Ustrcmp(sockip, "")){
 195     ipaddress = gethostbyname((char *)sockip);
 196     bzero((char *) &serv_addr_in, sizeof(serv_addr_in));
 197     serv_addr_in.sin_family = AF_INET;
 198     bcopy((char *)ipaddress->h_addr, (char *)&serv_addr_in.sin_addr.s_addr, ipaddress->h_length);
 199     serv_addr_in.sin_port = htons(portnr);
 200     if ((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){
 201       DEBUG(D_acl)
 202         debug_printf("Creating socket failed: %s\n", strerror(errno));
 203       log_write(0,LOG_REJECT,"Creating socket failed: %s\n", strerror(errno));
 204       /* if we cannot create the socket, defer the mail */
 205       (void)fclose(data_file);
 206       return retval;
 207     }
 208     /* Now connecting the socket (INET) */
 209     if (connect(sockfd, (struct sockaddr *)&serv_addr_in, sizeof(serv_addr_in)) < 0){
 210       DEBUG(D_acl)
 211         debug_printf("Connecting socket failed: %s\n", strerror(errno));
 212       log_write(0,LOG_REJECT,"Connecting socket failed: %s\n", strerror(errno));
 213       /* if we cannot contact the socket, defer the mail */
 214       (void)fclose(data_file);
 215       return retval;
 216     }
 217   } else {
 218     /* connecting to the dccifd UNIX socket */
 219     bzero((char *)&serv_addr,sizeof(serv_addr));
 220     serv_addr.sun_family = AF_UNIX;
 221     Ustrcpy(serv_addr.sun_path, sockpath);
 222     servlen = Ustrlen(serv_addr.sun_path) + sizeof(serv_addr.sun_family);
 223     if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0){
 224       DEBUG(D_acl)
 225         debug_printf("Creating socket failed: %s\n", strerror(errno));
 226       log_write(0,LOG_REJECT,"Creating socket failed: %s\n", strerror(errno));
 227       /* if we cannot create the socket, defer the mail */
 228       (void)fclose(data_file);
 229       return retval;
 230     }
 231     /* Now connecting the socket (UNIX) */
 232     if (connect(sockfd, (struct sockaddr *) &serv_addr, servlen) < 0){
 233       DEBUG(D_acl)
 234                             debug_printf("Connecting socket failed: %s\n", strerror(errno));
 235       log_write(0,LOG_REJECT,"Connecting socket failed: %s\n", strerror(errno));
 236       /* if we cannot contact the socket, defer the mail */
 237       (void)fclose(data_file);
 238       return retval;
 239     }
 240   }
 241   /* the socket is open, now send the options to dccifd*/
 242   DEBUG(D_acl)
 243     debug_printf("\n---------------------------\nSocket opened; now sending input\n-----------------\n");
 244   /* First, fill in the input buffer */
 245   Ustrncpy(sendbuf, opts, sizeof(sendbuf));
 246   Ustrncat(sendbuf, from, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 247
 248   DEBUG(D_acl)
 249   {
 250     debug_printf("opts = %s\nsender = %s\nrcpt count = %d\n", opts, from, recipients_count);
 251     debug_printf("Sending options:\n****************************\n");
 252   }
 253
 254   /* let's send each of the recipients to dccifd */
 255   for (i = 0; i < recipients_count; i++){
 256     DEBUG(D_acl)
 257       debug_printf("recipient = %s\n",recipients_list[i].address);
 258     if(Ustrlen(sendbuf) + Ustrlen(recipients_list[i].address) > sizeof(sendbuf))
 259     {
 260       DEBUG(D_acl)
 261         debug_printf("Writing buffer: %s\n", sendbuf);
 262       flushbuffer(sockfd, sendbuf);
 263       bzero(sendbuf, sizeof(sendbuf));
 264     }
 265     Ustrncat(sendbuf, recipients_list[i].address, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 266     Ustrncat(sendbuf, "\r\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 267   }
 268   /* send a blank line between options and message */
 269   Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 270   /* Now we send the input buffer */
 271   DEBUG(D_acl)
 272     debug_printf("%s\n****************************\n", sendbuf);
 273   flushbuffer(sockfd, sendbuf);
 274
 275   /* now send the message */
 276   /* Clear the input buffer */
 277   bzero(sendbuf, sizeof(sendbuf));
 278   /* First send the headers */
 279   /* Now send the headers */
 280   DEBUG(D_acl)
 281     debug_printf("Sending headers:\n****************************\n");
 282   Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
 283   while((dcchdr=dcchdr->next)) {
 284     if(dcchdr->slen > sizeof(sendbuf)-2) {
 285       /* The size of the header is bigger than the size of
 286        * the input buffer, so split it up in smaller parts. */
 287        flushbuffer(sockfd, sendbuf);
 288        bzero(sendbuf, sizeof(sendbuf));
 289        j = 0;
 290        while(j < dcchdr->slen)
 291        {
 292         for(i = 0; i < sizeof(sendbuf)-2; i++) {
 293           sendbuf[i] = dcchdr->text[j];
 294           j++;
 295         }
 296         flushbuffer(sockfd, sendbuf);
 297         bzero(sendbuf, sizeof(sendbuf));
 298        }
 299     } else if(Ustrlen(sendbuf) + dcchdr->slen > sizeof(sendbuf)-2) {
 300       flushbuffer(sockfd, sendbuf);
 301       bzero(sendbuf, sizeof(sendbuf));
 302       Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
 303     } else {
 304       Ustrncat(sendbuf, dcchdr->text, sizeof(sendbuf)-Ustrlen(sendbuf)-2);
 305     }
 306   }
 307
 308   /* a blank line separates header from body */
 309   Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 310   flushbuffer(sockfd, sendbuf);
 311   DEBUG(D_acl)
 312     debug_printf("\n****************************\n%s", sendbuf);
 313
 314   /* Clear the input buffer */
 315   bzero(sendbuf, sizeof(sendbuf));
 316
 317   /* now send the body */
 318   DEBUG(D_acl)
 319     debug_printf("Writing body:\n****************************\n");
 320   (void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);
 321   while((fread(sendbuf, 1, sizeof(sendbuf)-1, data_file)) > 0) {
 322     flushbuffer(sockfd, sendbuf);
 323     bzero(sendbuf, sizeof(sendbuf));
 324   }
 325   DEBUG(D_acl)
 326     debug_printf("\n****************************\n");
 327
 328   /* shutdown() the socket */
 329   if(shutdown(sockfd, 1) < 0){
 330     DEBUG(D_acl)
 331       debug_printf("Couldn't shutdown socket: %s\n", strerror(errno));
 332     log_write(0,LOG_MAIN,"Couldn't shutdown socket: %s\n", strerror(errno));
 333     /* If there is a problem with the shutdown()
 334      * defer the mail. */
 335     (void)fclose(data_file);
 336     return retval;
 337   }
 338   DEBUG(D_acl)
 339     debug_printf("\n-------------------------\nInput sent.\n-------------------------\n");
 340
 341     /********************************
 342    * receiving output from dccifd *
 343    ********************************/
 344   DEBUG(D_acl)
 345     debug_printf("\n-------------------------------------\nNow receiving output from server\n-----------------------------------\n");
 346
 347   /******************************************************************
 348    * We should get 3 lines:                                         *
 349    * 1/ First line is overall result: either 'A' for Accept,        *
 350    *    'R' for Reject, 'S' for accept Some recipients or           *
 351    *    'T' for a Temporary error.                                  *
 352    * 2/ Second line contains the list of Accepted/Rejected          *
 353    *    recipients in the form AARRA (A = accepted, R = rejected).  *
 354    * 3/ Third line contains the X-DCC header.                       *
 355    ******************************************************************/
 356
 357   line = 1;    /* we start at the first line of the output */
 358   j = 0;       /* will be used as index for the recipients list */
 359   k = 0;       /* initializing the index of the X-DCC header: xhdr[k] */
 360
 361   /* Let's read from the socket until there's nothing left to read */
 362   bzero(recvbuf, sizeof(recvbuf));
 363   while((resp = read(sockfd, recvbuf, sizeof(recvbuf)-1)) > 0) {
 364     /* How much did we get from the socket */
 365     c = Ustrlen(recvbuf) + 1;
 366     DEBUG(D_acl)
 367       debug_printf("Length of the output buffer is: %d\nOutput buffer is:\n------------\n%s\n-----------\n", c, recvbuf);
 368
 369     /* Now let's read each character and see what we've got */
 370     for(i = 0; i < c; i++) {
 371       /* First check if we reached the end of the line and
 372        * then increment the line counter */
 373       if(recvbuf[i] == '\n') {
 374         line++;
 375       }
 376       else {
 377         /* The first character of the first line is the
 378          * overall response. If there's another character
 379          * on that line it is not correct. */
 380         if(line == 1) {
 381           if(i == 0) {
 382             /* Now get the value and set the
 383              * return value accordingly */
 384             if(recvbuf[i] == 'A') {
 385               DEBUG(D_acl)
 386                 debug_printf("Overall result = A\treturning OK\n");
 387               Ustrcpy(dcc_return_text, "Mail accepted by DCC");
 388               dcc_result = US"A";
 389               retval = OK;
 390             }
 391             else if(recvbuf[i] == 'R') {
 392               DEBUG(D_acl)
 393                 debug_printf("Overall result = R\treturning FAIL\n");
 394               dcc_result = US"R";
 395               retval = FAIL;
 396               if(sender_host_name) {
 397                 log_write(0, LOG_MAIN, "H=%s [%s] F=<%s>: rejected by DCC", sender_host_name, sender_host_address, sender_address);
 398               }
 399               else {
 400                 log_write(0, LOG_MAIN, "H=[%s] F=<%s>: rejected by DCC", sender_host_address, sender_address);
 401               }
 402               Ustrncpy(dcc_return_text, dcc_reject_message, Ustrlen(dcc_reject_message) + 1);
 403             }
 404             else if(recvbuf[i] == 'S') {
 405               DEBUG(D_acl)
 406                 debug_printf("Overall result  = S\treturning OK\n");
 407               Ustrcpy(dcc_return_text, "Not all recipients accepted by DCC");
 408               /* Since we're in an ACL we want a global result
 409                * so we accept for all */
 410               dcc_result = US"A";
 411               retval = OK;
 412             }
 413             else if(recvbuf[i] == 'G') {
 414               DEBUG(D_acl)
 415                 debug_printf("Overall result  = G\treturning FAIL\n");
 416               Ustrcpy(dcc_return_text, "Greylisted by DCC");
 417               dcc_result = US"G";
 418               retval = FAIL;
 419             }
 420             else if(recvbuf[i] == 'T') {
 421               DEBUG(D_acl)
 422                 debug_printf("Overall result = T\treturning DEFER\n");
 423               retval = DEFER;
 424               log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", recvbuf);
 425               Ustrcpy(dcc_return_text, "Temporary error with DCC");
 426               dcc_result = US"T";
 427             }
 428             else {
 429               DEBUG(D_acl)
 430                 debug_printf("Overall result = something else\treturning DEFER\n");
 431               retval = DEFER;
 432               log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", recvbuf);
 433               Ustrcpy(dcc_return_text, "Unknown DCC response");
 434               dcc_result = US"T";
 435             }
 436           }
 437           else {
 438           /* We're on the first line but not on the first character,
 439            * there must be something wrong. */
 440             DEBUG(D_acl)
 441               debug_printf("Line = %d but i = %d != 0  character is %c - This is wrong!\n", line, i, recvbuf[i]);
 442               log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", recvbuf);
 443           }
 444         }
 445         else if(line == 2) {
 446           /* On the second line we get a list of
 447            * answer for each recipient. We don't care about
 448            * it because we're in an acl and so just take the
 449            * global result. */
 450         }
 451         else if(line > 2) {
 452           /* The third and following lines is the X-DCC header,
 453            * so we store it in xhdr. */
 454           /* check if we don't get more than what we can handle */
 455           if(k < sizeof(xhdr)) { /* xhdr has a length of 120 */
 456             xhdr[k] = recvbuf[i];
 457             k++;
 458           }
 459           else {
 460             DEBUG(D_acl)
 461               debug_printf("We got more output than we can store in the X-DCC header. Truncating at 120 characters.\n");
 462           }
 463         }
 464         else {
 465           /* Wrong line number. There must be a problem with the output. */
 466           DEBUG(D_acl)
 467             debug_printf("Wrong line number in output. Line number is %d\n", line);
 468         }
 469       }
 470     }
 471     /* we reinitialize the output buffer before we read again */
 472     bzero(recvbuf,sizeof(recvbuf));
 473   }
 474   /* We have read everything from the socket */
 475
 476   /* We need the terminate the X-DCC header with a '\n' character. This needs to be k-1
 477    * for xhdr[k] contains '\0'. */
 478   xhdr[k-1] = '\n';
 479
 480   /* Now let's sum up what we've got. */
 481   DEBUG(D_acl)
 482     debug_printf("\n--------------------------\nOverall result = %d\nX-DCC header: %sReturn message: %s\ndcc_result: %s\n", retval, xhdr, dcc_return_text, dcc_result);
 483
 484   /* We only add the X-DCC header if it starts with X-DCC */
 485   if(!(Ustrncmp(xhdr, "X-DCC", 5))){
 486     dcc_header = xhdr;
 487     if(dcc_direct_add_header) {
 488       header_add(' ' , "%s", xhdr);
 489   /* since the MIME ACL already writes the .eml file to disk without DCC Header we've to erase it */
 490       unspool_mbox();
 491     }
 492   }
 493   else {
 494     DEBUG(D_acl)
 495       debug_printf("Wrong format of the X-DCC header: %s\n", xhdr);
 496   }
 497
 498   /* check if we should add additional headers passed in acl_m_dcc_add_header */
 499   if(dcc_direct_add_header) {
 500     if (((xtra_hdrs = expand_string(US"$acl_m_dcc_add_header")) != NULL) && (xtra_hdrs[0] != '\0')) {
 501       Ustrncpy(dcc_xtra_hdrs, xtra_hdrs, sizeof(dcc_xtra_hdrs) - 2);
 502       if (dcc_xtra_hdrs[Ustrlen(dcc_xtra_hdrs)-1] != '\n')
 503         Ustrcat(dcc_xtra_hdrs, "\n");
 504       header_add(' ', "%s", dcc_xtra_hdrs);
 505       DEBUG(D_acl)
 506         debug_printf("adding additional headers in $acl_m_dcc_add_header: %s", dcc_xtra_hdrs);
 507     }
 508   }
 509
 510   dcc_ok = 1;
 511   /* Now return to exim main process */
 512   DEBUG(D_acl)
 513     debug_printf("Before returning to exim main process:\nreturn_text = %s - retval = %d\ndcc_result = %s\n", dcc_return_text, retval, dcc_result);
 514
 515   (void)fclose(data_file);
 516   return retval;
 517 }
 518
 519 #endif