src/src/dcc.c

   1 /* $Cambridge: exim/src/src/dcc.c,v 1.3 2009/10/13 15:08:03 tom 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   uschar *user_name;
  54   uschar *body_begin;
  55   uschar user_name_buffer[128];
  56   unsigned long mbox_size;
  57   FILE *data_file;
  58   int dcc_sock;
  59   uschar dcc_buffer[32600];
  60   uschar *dcc_daemon_ip = US"";
  61   int dcc_daemon_port = 6276;
  62   uschar *dcc_request = US"header";
  63   uschar *dcc_default_ip_option = US"127.0.0.1";
  64   uschar *dcc_ip_option = US"";
  65   uschar *dcc_helo_option = US"localhost";
  66   uschar *dcc_reject_message = US"Rejected by DCC";
  67   uschar *xtra_hdrs = NULL;
  68
  69   /* from local_scan */
  70   int i, j, k, c, retval, sockfd, servlen, resp, portnr, line;
  71   struct sockaddr_un  serv_addr;
  72   struct sockaddr_in  serv_addr_in;
  73   struct hostent *ipaddress;
  74   uschar sockpath[128];
  75   uschar sockip[40], client_ip[40];
  76   uschar opts[128];
  77   uschar rcpt[128], from[128];
  78   uschar sendbuf[4096];
  79   uschar recvbuf[4096];
  80   uschar xhdr[256];
  81   uschar dcc_return_text[1024];
  82   uschar mbox_path[1024];
  83   uschar message_subdir[2];
  84   struct header_line *dcchdr;
  85   struct recipient_item *dcc_rcpt = recipients_list;
  86   uschar *dcc_acl_options;
  87   uschar dcc_acl_options_buffer[10];
  88   uschar dcc_xtra_hdrs[1024];
  89
  90   int offset, result;
  91   uschar *p,*q;
  92   int override = 0;
  93   time_t start;
  94   struct sockaddr_un server;
  95 #ifndef NO_POLL_H
  96   struct pollfd pollfd;
  97 #endif
  98
  99   /* stop compiler warning */
 100   result = result;
 101
 102   /* grep 1st option */
 103   if ((dcc_acl_options = string_nextinlist(&list, &sep,
 104                                            dcc_acl_options_buffer,
 105                                            sizeof(dcc_acl_options_buffer))) != NULL)
 106   {
 107     /* parse 1st option */
 108     if ( (strcmpic(dcc_acl_options,US"false") == 0) ||
 109          (Ustrcmp(dcc_acl_options,"0") == 0) ) {
 110       /* explicitly no matching */
 111       return FAIL;
 112     };
 113
 114     /* special cases (match anything except empty) */
 115     if ( (strcmpic(dcc_acl_options,US"true") == 0) ||
 116          (Ustrcmp(dcc_acl_options,"*") == 0) ||
 117          (Ustrcmp(dcc_acl_options,"1") == 0) ) {
 118       dcc_acl_options = dcc_acl_options;
 119     };
 120   }
 121   else {
 122     /* empty means "don't match anything" */
 123     return FAIL;
 124   };
 125
 126   sep = 0;
 127
 128   /* if we scanned this message last time, just return */
 129   if ( dcc_ok )
 130       return dcc_rc;
 131
 132   /* open the spooled body */
 133   message_subdir[1] = '\0';
 134   for (i = 0; i < 2; i++) {
 135     message_subdir[0] = (split_spool_directory == (i == 0))? message_id[5] : 0;
 136     sprintf(CS mbox_path, "%s/input/%s/%s-D", spool_directory, message_subdir, message_id);
 137     data_file = Ufopen(mbox_path,"rb");
 138     if (data_file != NULL)
 139       break;
 140   };
 141
 142   if (data_file == NULL) {
 143     /* error while spooling */
 144     log_write(0, LOG_MAIN|LOG_PANIC,
 145            "dcc acl condition: error while opening spool file");
 146     return DEFER;
 147   };
 148
 149   /* Initialize the variables */
 150
 151   bzero(sockip,sizeof(sockip));
 152   if (dccifd_address) {
 153     if (dccifd_address[0] == '/')
 154       Ustrncpy(sockpath, dccifd_address, sizeof(sockpath));
 155     else
 156       if( sscanf(CS dccifd_address, "%s %u", sockip, portnr) != 2) {
 157         log_write(0, LOG_MAIN,
 158           "dcc acl condition: warning - invalid dccifd address: '%s'", dccifd_address);
 159         (void)fclose(data_file);
 160         return DEFER;
 161       }
 162   }
 163
 164   /* opts is what we send as dccifd options - see man dccifd */
 165   /* We don't support any other option than 'header' so just copy that */
 166   bzero(opts,sizeof(opts));
 167   Ustrncpy(opts, "header", sizeof(opts)-1);
 168   Ustrncpy(client_ip, dcc_ip_option, sizeof(client_ip)-1);
 169   /* If the dcc_client_ip is not provided use the
 170    * sender_host_address or 127.0.0.1 if it is NULL */
 171   DEBUG(D_acl)
 172     debug_printf("my_ip_option = %s - client_ip = %s - sender_host_address = %s\n", dcc_ip_option, client_ip, sender_host_address);
 173   if(!(Ustrcmp(client_ip, ""))){
 174     /* Do we have a sender_host_address or is it NULL? */
 175     if(sender_host_address){
 176       Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
 177     } else {
 178       /* sender_host_address is NULL which means it comes from localhost */
 179       Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
 180     }
 181   }
 182   DEBUG(D_acl)
 183     debug_printf("Client IP: %s\n", client_ip);
 184   Ustrncpy(sockip, dcc_daemon_ip, sizeof(sockip)-1);
 185   /* strncat(opts, my_request, strlen(my_request)); */
 186   Ustrcat(opts, "\n");
 187   Ustrncat(opts, client_ip, sizeof(opts)-Ustrlen(opts)-1);
 188   Ustrncat(opts, "\nHELO ", sizeof(opts)-Ustrlen(opts)-1);
 189   Ustrncat(opts, dcc_helo_option, sizeof(opts)-Ustrlen(opts)-2);
 190   Ustrcat(opts, "\n");
 191
 192   /* initialize the other variables */
 193   dcchdr = header_list;
 194   /* we set the default return value to DEFER */
 195   retval = DEFER;
 196
 197   bzero(sendbuf,sizeof(sendbuf));
 198   bzero(xhdr,sizeof(xhdr));
 199   bzero(rcpt,sizeof(rcpt));
 200   bzero(from,sizeof(from));
 201
 202   /* send a null return path as "<>". */
 203   if (Ustrlen(sender_address) > 0)
 204     Ustrncpy(from, sender_address, sizeof(from));
 205   else
 206     Ustrncpy(from, "<>", sizeof(from));
 207   Ustrncat(from, "\n", sizeof(from)-Ustrlen(from)-1);
 208
 209   /**************************************
 210    * Now creating the socket connection *
 211    **************************************/
 212
 213   /* If there is a dcc_daemon_ip, we use a tcp socket, otherwise a UNIX socket */
 214   if(Ustrcmp(sockip, "")){
 215     ipaddress = gethostbyname((char *)sockip);
 216     bzero((char *) &serv_addr_in, sizeof(serv_addr_in));
 217     serv_addr_in.sin_family = AF_INET;
 218     bcopy((char *)ipaddress->h_addr, (char *)&serv_addr_in.sin_addr.s_addr, ipaddress->h_length);
 219     serv_addr_in.sin_port = htons(portnr);
 220     if ((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){
 221       DEBUG(D_acl)
 222         debug_printf("Creating socket failed: %s\n", strerror(errno));
 223       log_write(0,LOG_REJECT,"Creating socket failed: %s\n", strerror(errno));
 224       /* if we cannot create the socket, defer the mail */
 225       (void)fclose(data_file);
 226       return retval;
 227     }
 228     /* Now connecting the socket (INET) */
 229     if (connect(sockfd, (struct sockaddr *)&serv_addr_in, sizeof(serv_addr_in)) < 0){
 230       DEBUG(D_acl)
 231         debug_printf("Connecting socket failed: %s\n", strerror(errno));
 232       log_write(0,LOG_REJECT,"Connecting socket failed: %s\n", strerror(errno));
 233       /* if we cannot contact the socket, defer the mail */
 234       (void)fclose(data_file);
 235       return retval;
 236     }
 237   } else {
 238     /* connecting to the dccifd UNIX socket */
 239     bzero((char *)&serv_addr,sizeof(serv_addr));
 240     serv_addr.sun_family = AF_UNIX;
 241     Ustrcpy(serv_addr.sun_path, sockpath);
 242     servlen = Ustrlen(serv_addr.sun_path) + sizeof(serv_addr.sun_family);
 243     if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0){
 244       DEBUG(D_acl)
 245         debug_printf("Creating socket failed: %s\n", strerror(errno));
 246       log_write(0,LOG_REJECT,"Creating socket failed: %s\n", strerror(errno));
 247       /* if we cannot create the socket, defer the mail */
 248       (void)fclose(data_file);
 249       return retval;
 250     }
 251     /* Now connecting the socket (UNIX) */
 252     if (connect(sockfd, (struct sockaddr *) &serv_addr, servlen) < 0){
 253       DEBUG(D_acl)
 254                             debug_printf("Connecting socket failed: %s\n", strerror(errno));
 255       log_write(0,LOG_REJECT,"Connecting socket failed: %s\n", strerror(errno));
 256       /* if we cannot contact the socket, defer the mail */
 257       (void)fclose(data_file);
 258       return retval;
 259     }
 260   }
 261   /* the socket is open, now send the options to dccifd*/
 262   DEBUG(D_acl)
 263     debug_printf("\n---------------------------\nSocket opened; now sending input\n-----------------\n");
 264   /* First, fill in the input buffer */
 265   Ustrncpy(sendbuf, opts, sizeof(sendbuf));
 266   Ustrncat(sendbuf, from, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 267
 268   DEBUG(D_acl)
 269   {
 270     debug_printf("opts = %s\nsender = %s\nrcpt count = %d\n", opts, from, recipients_count);
 271     debug_printf("Sending options:\n****************************\n");
 272   }
 273
 274   /* let's send each of the recipients to dccifd */
 275   for (i = 0; i < recipients_count; i++){
 276     DEBUG(D_acl)
 277       debug_printf("recipient = %s\n",recipients_list[i].address);
 278     if(Ustrlen(sendbuf) + Ustrlen(recipients_list[i].address) > sizeof(sendbuf))
 279     {
 280       DEBUG(D_acl)
 281         debug_printf("Writing buffer: %s\n", sendbuf);
 282       flushbuffer(sockfd, sendbuf);
 283       bzero(sendbuf, sizeof(sendbuf));
 284     }
 285     Ustrncat(sendbuf, recipients_list[i].address, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 286     Ustrncat(sendbuf, "\r\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 287   }
 288   /* send a blank line between options and message */
 289   Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 290   /* Now we send the input buffer */
 291   DEBUG(D_acl)
 292     debug_printf("%s\n****************************\n", sendbuf);
 293   flushbuffer(sockfd, sendbuf);
 294
 295   /* now send the message */
 296   /* Clear the input buffer */
 297   bzero(sendbuf, sizeof(sendbuf));
 298   /* First send the headers */
 299   /* Now send the headers */
 300   DEBUG(D_acl)
 301     debug_printf("Sending headers:\n****************************\n");
 302   Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
 303   while((dcchdr=dcchdr->next)) {
 304     if(dcchdr->slen > sizeof(sendbuf)-2) {
 305       /* The size of the header is bigger than the size of
 306        * the input buffer, so split it up in smaller parts. */
 307        flushbuffer(sockfd, sendbuf);
 308        bzero(sendbuf, sizeof(sendbuf));
 309        j = 0;
 310        while(j < dcchdr->slen)
 311        {
 312         for(i = 0; i < sizeof(sendbuf)-2; i++) {
 313           sendbuf[i] = dcchdr->text[j];
 314           j++;
 315         }
 316         flushbuffer(sockfd, sendbuf);
 317         bzero(sendbuf, sizeof(sendbuf));
 318        }
 319     } else if(Ustrlen(sendbuf) + dcchdr->slen > sizeof(sendbuf)-2) {
 320       flushbuffer(sockfd, sendbuf);
 321       bzero(sendbuf, sizeof(sendbuf));
 322       Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
 323     } else {
 324       Ustrncat(sendbuf, dcchdr->text, sizeof(sendbuf)-Ustrlen(sendbuf)-2);
 325     }
 326   }
 327
 328   /* a blank line separates header from body */
 329   Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
 330   flushbuffer(sockfd, sendbuf);
 331   DEBUG(D_acl)
 332     debug_printf("\n****************************\n", sendbuf);
 333
 334   /* Clear the input buffer */
 335   bzero(sendbuf, sizeof(sendbuf));
 336
 337   /* now send the body */
 338   DEBUG(D_acl)
 339     debug_printf("Writing body:\n****************************\n");
 340   (void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);
 341   while((fread(sendbuf, 1, sizeof(sendbuf)-1, data_file)) > 0) {
 342     flushbuffer(sockfd, sendbuf);
 343     bzero(sendbuf, sizeof(sendbuf));
 344   }
 345   DEBUG(D_acl)
 346     debug_printf("\n****************************\n");
 347
 348   /* shutdown() the socket */
 349   if(shutdown(sockfd, 1) < 0){
 350     DEBUG(D_acl)
 351       debug_printf("Couldn't shutdown socket: %s\n", strerror(errno));
 352     log_write(0,LOG_MAIN,"Couldn't shutdown socket: %s\n", strerror(errno));
 353     /* If there is a problem with the shutdown()
 354      * defer the mail. */
 355     (void)fclose(data_file);
 356     return retval;
 357   }
 358   DEBUG(D_acl)
 359     debug_printf("\n-------------------------\nInput sent.\n-------------------------\n");
 360
 361     /********************************
 362    * receiving output from dccifd *
 363    ********************************/
 364   DEBUG(D_acl)
 365     debug_printf("\n-------------------------------------\nNow receiving output from server\n-----------------------------------\n");
 366
 367   /******************************************************************
 368    * We should get 3 lines:                                         *
 369    * 1/ First line is overall result: either 'A' for Accept,        *
 370    *    'R' for Reject, 'S' for accept Some recipients or           *
 371    *    'T' for a Temporary error.                                  *
 372    * 2/ Second line contains the list of Accepted/Rejected          *
 373    *    recipients in the form AARRA (A = accepted, R = rejected).  *
 374    * 3/ Third line contains the X-DCC header.                       *
 375    ******************************************************************/
 376
 377   line = 1;    /* we start at the first line of the output */
 378   j = 0;       /* will be used as index for the recipients list */
 379   k = 0;       /* initializing the index of the X-DCC header: xhdr[k] */
 380
 381   /* Let's read from the socket until there's nothing left to read */
 382   bzero(recvbuf, sizeof(recvbuf));
 383   while(resp = read(sockfd, recvbuf, sizeof(recvbuf)-1) > 0) {
 384     /* How much did we get from the socket */
 385     c = Ustrlen(recvbuf) + 1;
 386     DEBUG(D_acl)
 387       debug_printf("Length of the output buffer is: %d\nOutput buffer is:\n------------\n%s\n-----------\n", c, recvbuf);
 388
 389     /* Now let's read each character and see what we've got */
 390     for(i = 0; i < c; i++) {
 391       /* First check if we reached the end of the line and
 392        * then increment the line counter */
 393       if(recvbuf[i] == '\n') {
 394         line++;
 395       }
 396       else {
 397         /* The first character of the first line is the
 398          * overall response. If there's another character
 399          * on that line it is not correct. */
 400         if(line == 1) {
 401           if(i == 0) {
 402             /* Now get the value and set the
 403              * return value accordingly */
 404             if(recvbuf[i] == 'A') {
 405               DEBUG(D_acl)
 406                 debug_printf("Overall result = A\treturning OK\n");
 407               Ustrcpy(dcc_return_text, "Mail accepted by DCC");
 408               dcc_result = "A";
 409               retval = OK;
 410             }
 411             else if(recvbuf[i] == 'R') {
 412               DEBUG(D_acl)
 413                 debug_printf("Overall result = R\treturning FAIL\n");
 414               dcc_result = "R";
 415               retval = FAIL;
 416               if(sender_host_name) {
 417                 log_write(0, LOG_MAIN, "H=%s [%s] F=<%s>: rejected by DCC", sender_host_name, sender_host_address, sender_address);
 418               }
 419               else {
 420                 log_write(0, LOG_MAIN, "H=[%s] F=<%s>: rejected by DCC", sender_host_address, sender_address);
 421               }
 422               Ustrncpy(dcc_return_text, dcc_reject_message, Ustrlen(dcc_reject_message) + 1);
 423             }
 424             else if(recvbuf[i] == 'S') {
 425               DEBUG(D_acl)
 426                 debug_printf("Overall result  = S\treturning OK\n");
 427               Ustrcpy(dcc_return_text, "Not all recipients accepted by DCC");
 428               /* Since we're in an ACL we want a global result
 429                * so we accept for all */
 430               dcc_result = "A";
 431               retval = OK;
 432             }
 433             else if(recvbuf[i] == 'G') {
 434               DEBUG(D_acl)
 435                 debug_printf("Overall result  = G\treturning FAIL\n");
 436               Ustrcpy(dcc_return_text, "Greylisted by DCC");
 437               dcc_result = "G";
 438               retval = FAIL;
 439             }
 440             else if(recvbuf[i] == 'T') {
 441               DEBUG(D_acl)
 442                 debug_printf("Overall result = T\treturning DEFER\n");
 443               retval = DEFER;
 444               log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", recvbuf);
 445               Ustrcpy(dcc_return_text, "Temporary error with DCC");
 446               dcc_result = "T";
 447             }
 448             else {
 449               DEBUG(D_acl)
 450                 debug_printf("Overall result = something else\treturning DEFER\n");
 451               retval = DEFER;
 452               log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", recvbuf);
 453               Ustrcpy(dcc_return_text, "Unknown DCC response");
 454               dcc_result = "T";
 455             }
 456           }
 457           else {
 458           /* We're on the first line but not on the first character,
 459            * there must be something wrong. */
 460             DEBUG(D_acl)
 461               debug_printf("Line = %d but i = %d != 0  character is %c - This is wrong!\n", line, i, recvbuf[i]);
 462               log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", recvbuf);
 463           }
 464         }
 465         else if(line == 2) {
 466           /* On the second line we get a list of
 467            * answer for each recipient. We don't care about
 468            * it because we're in an acl and so just take the
 469            * global result. */
 470         }
 471         else if(line > 2) {
 472           /* The third and following lines is the X-DCC header,
 473            * so we store it in xhdr. */
 474           /* check if we don't get more than what we can handle */
 475           if(k < sizeof(xhdr)) { /* xhdr has a length of 120 */
 476             xhdr[k] = recvbuf[i];
 477             k++;
 478           }
 479           else {
 480             DEBUG(D_acl)
 481               debug_printf("We got more output than we can store in the X-DCC header. Truncating at 120 characters.\n");
 482           }
 483         }
 484         else {
 485           /* Wrong line number. There must be a problem with the output. */
 486           DEBUG(D_acl)
 487             debug_printf("Wrong line number in output. Line number is %d\n", line);
 488         }
 489       }
 490     }
 491     /* we reinitialize the output buffer before we read again */
 492     bzero(recvbuf,sizeof(recvbuf));
 493   }
 494   /* We have read everything from the socket */
 495
 496   /* We need the terminate the X-DCC header with a '\n' character. This needs to be k-1
 497    * for xhdr[k] contains '\0'. */
 498   xhdr[k-1] = '\n';
 499
 500   /* Now let's sum up what we've got. */
 501   DEBUG(D_acl)
 502     debug_printf("\n--------------------------\nOverall result = %d\nX-DCC header: %sReturn message: %s\ndcc_result: %s\n", retval, xhdr, dcc_return_text, dcc_result);
 503
 504   /* We only add the X-DCC header if it starts with X-DCC */
 505   if(!(Ustrncmp(xhdr, "X-DCC", 5))){
 506     dcc_header = xhdr;
 507     if(dcc_direct_add_header) {
 508       header_add(' ' , "%s", xhdr);
 509   /* since the MIME ACL already writes the .eml file to disk without DCC Header we've to erase it */
 510       unspool_mbox();
 511     }
 512   }
 513   else {
 514     DEBUG(D_acl)
 515       debug_printf("Wrong format of the X-DCC header: %s\n", xhdr);
 516   }
 517
 518   /* check if we should add additional headers passed in acl_m_dcc_add_header */
 519   if(dcc_direct_add_header) {
 520     if (((xtra_hdrs = expand_string("$acl_m_dcc_add_header")) != NULL) && (xtra_hdrs[0] != '\0')) {
 521       Ustrncpy(dcc_xtra_hdrs, xtra_hdrs, sizeof(dcc_xtra_hdrs) - 2);
 522       if (dcc_xtra_hdrs[Ustrlen(dcc_xtra_hdrs)-1] != '\n')
 523         Ustrcat(dcc_xtra_hdrs, "\n");
 524       header_add(' ', "%s", dcc_xtra_hdrs);
 525       DEBUG(D_acl)
 526         debug_printf("adding additional headers in $acl_m_dcc_add_header: %s", dcc_xtra_hdrs);
 527     }
 528   }
 529
 530   dcc_ok = 1;
 531   /* Now return to exim main process */
 532   DEBUG(D_acl)
 533     debug_printf("Before returning to exim main process:\nreturn_text = %s - retval = %d\ndcc_result = %s\n", dcc_return_text, retval, dcc_result);
 534
 535   (void)fclose(data_file);
 536   return retval;
 537 }
 538
 539 #endif