/************************************************* * Exim - an Internet mail transport agent * *************************************************/ /* Copyright (c) Wolfgang Breyha 2005 - 2015 * Vienna University Computer Center * wbreyha@gmx.net * See the file NOTICE for conditions of use and distribution. * * Copyright (c) The Exim Maintainers 2015 - 2018 */ /* This patch is based on code from Tom Kistners exiscan (ACL integration) and * the DCC local_scan patch from Christopher Bodenstein */ /* Code for calling dccifd. Called from acl.c. */ #include "exim.h" #ifdef EXPERIMENTAL_DCC #include "dcc.h" #include "unistd.h" uschar dcc_header_str[256]; int dcc_ok = 0; int dcc_rc = 0; /* This function takes a file descriptor and a buffer as input and * returns either 0 for success or errno in case of error. */ int flushbuffer (int socket, uschar *buffer) { int retval, rsp; rsp = write(socket, buffer, Ustrlen(buffer)); DEBUG(D_acl) debug_printf("DCC: Result of the write() = %d\n", rsp); if(rsp < 0) { DEBUG(D_acl) debug_printf("DCC: Error writing buffer to socket: %s\n", strerror(errno)); retval = errno; } else { DEBUG(D_acl) debug_printf("DCC: Wrote buffer to socket:\n%s\n", buffer); retval = 0; } return retval; } int dcc_process(uschar **listptr) { int sep = 0; const uschar *list = *listptr; FILE *data_file; uschar *dcc_default_ip_option = US"127.0.0.1"; uschar *dcc_helo_option = US"localhost"; uschar *dcc_reject_message = US"Rejected by DCC"; uschar *xtra_hdrs = NULL; uschar *override_client_ip = NULL; /* from local_scan */ int i, j, k, c, retval, sockfd, resp, line; unsigned int portnr; struct sockaddr_un serv_addr; struct sockaddr_in serv_addr_in; struct hostent *ipaddress; uschar sockpath[128]; uschar sockip[40], client_ip[40]; uschar opts[128]; uschar rcpt[128], from[128]; uschar sendbuf[4096]; uschar recvbuf[4096]; uschar dcc_return_text[1024]; uschar message_subdir[2]; struct header_line *dcchdr; uschar *dcc_acl_options; uschar dcc_acl_options_buffer[10]; uschar dcc_xtra_hdrs[1024]; /* grep 1st option */ if ((dcc_acl_options = string_nextinlist(&list, &sep, dcc_acl_options_buffer, sizeof(dcc_acl_options_buffer)))) { /* parse 1st option */ if ( strcmpic(dcc_acl_options, US"false") == 0 || Ustrcmp(dcc_acl_options, "0") == 0 ) return FAIL; /* explicitly no matching */ } else return FAIL; /* empty means "don't match anything" */ sep = 0; /* if we scanned this message last time, just return */ if (dcc_ok) return dcc_rc; /* open the spooled body */ message_subdir[1] = '\0'; for (i = 0; i < 2; i++) { message_subdir[0] = split_spool_directory == (i == 0) ? message_id[5] : 0; if ((data_file = Ufopen( spool_fname(US"input", message_subdir, message_id, US"-D"), "rb"))) break; } if (!data_file) { /* error while spooling */ log_write(0, LOG_MAIN|LOG_PANIC, "dcc acl condition: error while opening spool file"); return DEFER; } /* Initialize the variables */ bzero(sockip,sizeof(sockip)); if (dccifd_address) { if (dccifd_address[0] == '/') Ustrncpy(sockpath, dccifd_address, sizeof(sockpath)); else if( sscanf(CS dccifd_address, "%s %u", sockip, &portnr) != 2) { log_write(0, LOG_MAIN, "dcc acl condition: warning - invalid dccifd address: '%s'", dccifd_address); (void)fclose(data_file); return DEFER; } } /* opts is what we send as dccifd options - see man dccifd */ /* We don't support any other option than 'header' so just copy that */ bzero(opts,sizeof(opts)); Ustrncpy(opts, dccifd_options, sizeof(opts)-1); /* if $acl_m_dcc_override_client_ip is set use it */ if (((override_client_ip = expand_string(US"$acl_m_dcc_override_client_ip")) != NULL) && (override_client_ip[0] != '\0')) { Ustrncpy(client_ip, override_client_ip, sizeof(client_ip)-1); DEBUG(D_acl) debug_printf("DCC: Client IP (overridden): %s\n", client_ip); } else if(sender_host_address) { /* else if $sender_host_address is available use that? */ Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1); DEBUG(D_acl) debug_printf("DCC: Client IP (sender_host_address): %s\n", client_ip); } else { /* sender_host_address is NULL which means it comes from localhost */ Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1); DEBUG(D_acl) debug_printf("DCC: Client IP (default): %s\n", client_ip); } /* strncat(opts, my_request, strlen(my_request)); */ Ustrcat(opts, "\n"); Ustrncat(opts, client_ip, sizeof(opts)-Ustrlen(opts)-1); Ustrncat(opts, "\nHELO ", sizeof(opts)-Ustrlen(opts)-1); Ustrncat(opts, dcc_helo_option, sizeof(opts)-Ustrlen(opts)-2); Ustrcat(opts, "\n"); /* initialize the other variables */ dcchdr = header_list; /* we set the default return value to DEFER */ retval = DEFER; bzero(sendbuf,sizeof(sendbuf)); bzero(dcc_header_str,sizeof(dcc_header_str)); bzero(rcpt,sizeof(rcpt)); bzero(from,sizeof(from)); /* send a null return path as "<>". */ if (Ustrlen(sender_address) > 0) Ustrncpy(from, sender_address, sizeof(from)); else Ustrncpy(from, "<>", sizeof(from)); Ustrncat(from, "\n", sizeof(from)-Ustrlen(from)-1); /************************************** * Now creating the socket connection * **************************************/ /* If sockip contains an ip, we use a tcp socket, otherwise a UNIX socket */ if(Ustrcmp(sockip, "")){ ipaddress = gethostbyname(CS sockip); bzero(CS &serv_addr_in, sizeof(serv_addr_in)); serv_addr_in.sin_family = AF_INET; bcopy(CS ipaddress->h_addr, CS &serv_addr_in.sin_addr.s_addr, ipaddress->h_length); serv_addr_in.sin_port = htons(portnr); if ((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){ DEBUG(D_acl) debug_printf("DCC: Creating TCP socket connection failed: %s\n", strerror(errno)); log_write(0,LOG_PANIC,"DCC: Creating TCP socket connection failed: %s\n", strerror(errno)); /* if we cannot create the socket, defer the mail */ (void)fclose(data_file); return retval; } /* Now connecting the socket (INET) */ if (connect(sockfd, (struct sockaddr *)&serv_addr_in, sizeof(serv_addr_in)) < 0){ DEBUG(D_acl) debug_printf("DCC: Connecting to TCP socket failed: %s\n", strerror(errno)); log_write(0,LOG_PANIC,"DCC: Connecting to TCP socket failed: %s\n", strerror(errno)); /* if we cannot contact the socket, defer the mail */ (void)fclose(data_file); return retval; } } else { /* connecting to the dccifd UNIX socket */ bzero(&serv_addr, sizeof(serv_addr)); serv_addr.sun_family = AF_UNIX; Ustrncpy(serv_addr.sun_path, sockpath, sizeof(serv_addr.sun_path)); if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0){ DEBUG(D_acl) debug_printf("DCC: Creating UNIX socket connection failed: %s\n", strerror(errno)); log_write(0,LOG_PANIC,"DCC: Creating UNIX socket connection failed: %s\n", strerror(errno)); /* if we cannot create the socket, defer the mail */ (void)fclose(data_file); return retval; } /* Now connecting the socket (UNIX) */ if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0){ DEBUG(D_acl) debug_printf("DCC: Connecting to UNIX socket failed: %s\n", strerror(errno)); log_write(0,LOG_PANIC,"DCC: Connecting to UNIX socket failed: %s\n", strerror(errno)); /* if we cannot contact the socket, defer the mail */ (void)fclose(data_file); return retval; } } /* the socket is open, now send the options to dccifd*/ DEBUG(D_acl) debug_printf("\nDCC: ---------------------------\nDCC: Socket opened; now sending input\nDCC: -----------------\n"); /* First, fill in the input buffer */ Ustrncpy(sendbuf, opts, sizeof(sendbuf)); Ustrncat(sendbuf, from, sizeof(sendbuf)-Ustrlen(sendbuf)-1); DEBUG(D_acl) { debug_printf("DCC: opts = %s\nDCC: sender = %s\nDCC: rcpt count = %d\n", opts, from, recipients_count); debug_printf("DCC: Sending options:\nDCC: ****************************\n"); } /* let's send each of the recipients to dccifd */ for (i = 0; i < recipients_count; i++){ DEBUG(D_acl) debug_printf("DCC: recipient = %s\n",recipients_list[i].address); if(Ustrlen(sendbuf) + Ustrlen(recipients_list[i].address) > sizeof(sendbuf)) { DEBUG(D_acl) debug_printf("DCC: Writing buffer: %s\n", sendbuf); flushbuffer(sockfd, sendbuf); bzero(sendbuf, sizeof(sendbuf)); } Ustrncat(sendbuf, recipients_list[i].address, sizeof(sendbuf)-Ustrlen(sendbuf)-1); Ustrncat(sendbuf, "\r\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1); } /* send a blank line between options and message */ Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1); /* Now we send the input buffer */ DEBUG(D_acl) debug_printf("DCC: %s\nDCC: ****************************\n", sendbuf); flushbuffer(sockfd, sendbuf); /* now send the message */ /* Clear the input buffer */ bzero(sendbuf, sizeof(sendbuf)); /* First send the headers */ /* Now send the headers */ DEBUG(D_acl) debug_printf("DCC: Sending headers:\nDCC: ****************************\n"); Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2); while((dcchdr=dcchdr->next)) { if(dcchdr->slen > sizeof(sendbuf)-2) { /* The size of the header is bigger than the size of * the input buffer, so split it up in smaller parts. */ flushbuffer(sockfd, sendbuf); bzero(sendbuf, sizeof(sendbuf)); j = 0; while(j < dcchdr->slen) { for(i = 0; i < sizeof(sendbuf)-2; i++) { sendbuf[i] = dcchdr->text[j]; j++; } flushbuffer(sockfd, sendbuf); bzero(sendbuf, sizeof(sendbuf)); } } else if(Ustrlen(sendbuf) + dcchdr->slen > sizeof(sendbuf)-2) { flushbuffer(sockfd, sendbuf); bzero(sendbuf, sizeof(sendbuf)); Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2); } else { Ustrncat(sendbuf, dcchdr->text, sizeof(sendbuf)-Ustrlen(sendbuf)-2); } } /* a blank line separates header from body */ Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1); flushbuffer(sockfd, sendbuf); DEBUG(D_acl) debug_printf("\nDCC: ****************************\n%s", sendbuf); /* Clear the input buffer */ bzero(sendbuf, sizeof(sendbuf)); /* now send the body */ DEBUG(D_acl) debug_printf("DCC: Writing body:\nDCC: ****************************\n"); (void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET); while((fread(sendbuf, 1, sizeof(sendbuf)-1, data_file)) > 0) { flushbuffer(sockfd, sendbuf); bzero(sendbuf, sizeof(sendbuf)); } DEBUG(D_acl) debug_printf("\nDCC: ****************************\n"); /* shutdown() the socket */ if(shutdown(sockfd, 1) < 0){ DEBUG(D_acl) debug_printf("DCC: Couldn't shutdown socket: %s\n", strerror(errno)); log_write(0,LOG_MAIN,"DCC: Couldn't shutdown socket: %s\n", strerror(errno)); /* If there is a problem with the shutdown() * defer the mail. */ (void)fclose(data_file); return retval; } DEBUG(D_acl) debug_printf("\nDCC: -------------------------\nDCC: Input sent.\nDCC: -------------------------\n"); /******************************** * receiving output from dccifd * ********************************/ DEBUG(D_acl) debug_printf("\nDCC: -------------------------------------\nDCC: Now receiving output from server\nDCC: -----------------------------------\n"); /****************************************************************** * We should get 3 lines: * * 1/ First line is overall result: either 'A' for Accept, * * 'R' for Reject, 'S' for accept Some recipients or * * 'T' for a Temporary error. * * 2/ Second line contains the list of Accepted/Rejected * * recipients in the form AARRA (A = accepted, R = rejected). * * 3/ Third line contains the X-DCC header. * ******************************************************************/ line = 1; /* we start at the first line of the output */ j = 0; /* will be used as index for the recipients list */ k = 0; /* initializing the index of the X-DCC header: dcc_header_str[k] */ /* Let's read from the socket until there's nothing left to read */ bzero(recvbuf, sizeof(recvbuf)); while((resp = read(sockfd, recvbuf, sizeof(recvbuf)-1)) > 0) { /* How much did we get from the socket */ c = Ustrlen(recvbuf) + 1; DEBUG(D_acl) debug_printf("DCC: Length of the output buffer is: %d\nDCC: Output buffer is:\nDCC: ------------\nDCC: %s\nDCC: -----------\n", c, recvbuf); /* Now let's read each character and see what we've got */ for(i = 0; i < c; i++) { /* First check if we reached the end of the line and * then increment the line counter */ if(recvbuf[i] == '\n') { line++; } else { /* The first character of the first line is the * overall response. If there's another character * on that line it is not correct. */ if(line == 1) { if(i == 0) { /* Now get the value and set the * return value accordingly */ if(recvbuf[i] == 'A') { DEBUG(D_acl) debug_printf("DCC: Overall result = A\treturning OK\n"); Ustrcpy(dcc_return_text, "Mail accepted by DCC"); dcc_result = US"A"; retval = OK; } else if(recvbuf[i] == 'R') { DEBUG(D_acl) debug_printf("DCC: Overall result = R\treturning FAIL\n"); dcc_result = US"R"; retval = FAIL; if(sender_host_name) { log_write(0, LOG_MAIN, "H=%s [%s] F=<%s>: rejected by DCC", sender_host_name, sender_host_address, sender_address); } else { log_write(0, LOG_MAIN, "H=[%s] F=<%s>: rejected by DCC", sender_host_address, sender_address); } Ustrncpy(dcc_return_text, dcc_reject_message, Ustrlen(dcc_reject_message) + 1); } else if(recvbuf[i] == 'S') { DEBUG(D_acl) debug_printf("DCC: Overall result = S\treturning OK\n"); Ustrcpy(dcc_return_text, "Not all recipients accepted by DCC"); /* Since we're in an ACL we want a global result * so we accept for all */ dcc_result = US"A"; retval = OK; } else if(recvbuf[i] == 'G') { DEBUG(D_acl) debug_printf("DCC: Overall result = G\treturning FAIL\n"); Ustrcpy(dcc_return_text, "Greylisted by DCC"); dcc_result = US"G"; retval = FAIL; } else if(recvbuf[i] == 'T') { DEBUG(D_acl) debug_printf("DCC: Overall result = T\treturning DEFER\n"); retval = DEFER; log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", recvbuf); Ustrcpy(dcc_return_text, "Temporary error with DCC"); dcc_result = US"T"; } else { DEBUG(D_acl) debug_printf("DCC: Overall result = something else\treturning DEFER\n"); retval = DEFER; log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", recvbuf); Ustrcpy(dcc_return_text, "Unknown DCC response"); dcc_result = US"T"; } } else { /* We're on the first line but not on the first character, * there must be something wrong. */ DEBUG(D_acl) debug_printf("DCC: Line = %d but i = %d != 0" " character is %c - This is wrong!\n", line, i, recvbuf[i]); log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", recvbuf); } } else if(line == 2) { /* On the second line we get a list of * answers for each recipient. We don't care about * it because we're in an acl and take the * global result. */ } else if(line > 2) { /* The third and following lines are the X-DCC header, * so we store it in dcc_header_str. */ /* check if we don't get more than we can handle */ if(k < sizeof(dcc_header_str)) { dcc_header_str[k] = recvbuf[i]; k++; } else { DEBUG(D_acl) debug_printf("DCC: We got more output than we can store" " in the X-DCC header. Truncating at 120 characters.\n"); } } else { /* Wrong line number. There must be a problem with the output. */ DEBUG(D_acl) debug_printf("DCC: Wrong line number in output. Line number is %d\n", line); } } } /* we reinitialize the output buffer before we read again */ bzero(recvbuf,sizeof(recvbuf)); } /* We have read everything from the socket */ /* We need to terminate the X-DCC header with a '\n' character. This needs to be k-1 * since dcc_header_str[k] contains '\0'. */ dcc_header_str[k-1] = '\n'; /* Now let's sum up what we've got. */ DEBUG(D_acl) 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); /* We only add the X-DCC header if it starts with X-DCC */ if(!(Ustrncmp(dcc_header_str, "X-DCC", 5))){ dcc_header = dcc_header_str; if(dcc_direct_add_header) { header_add(' ' , "%s", dcc_header_str); /* since the MIME ACL already writes the .eml file to disk without DCC Header we've to erase it */ unspool_mbox(); } } else { DEBUG(D_acl) debug_printf("DCC: Wrong format of the X-DCC header: %s\n", dcc_header_str); } /* check if we should add additional headers passed in acl_m_dcc_add_header */ if(dcc_direct_add_header) { if (((xtra_hdrs = expand_string(US"$acl_m_dcc_add_header")) != NULL) && (xtra_hdrs[0] != '\0')) { Ustrncpy(dcc_xtra_hdrs, xtra_hdrs, sizeof(dcc_xtra_hdrs) - 2); if (dcc_xtra_hdrs[Ustrlen(dcc_xtra_hdrs)-1] != '\n') Ustrcat(dcc_xtra_hdrs, "\n"); header_add(' ', "%s", dcc_xtra_hdrs); DEBUG(D_acl) debug_printf("DCC: adding additional headers in $acl_m_dcc_add_header: %s", dcc_xtra_hdrs); } } dcc_ok = 1; /* Now return to exim main process */ DEBUG(D_acl) 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); (void)fclose(data_file); dcc_rc = retval; return dcc_rc; } #endif