1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) Wolfgang Breyha 2005 - 2015
6 * Vienna University Computer Center
8 * See the file NOTICE for conditions of use and distribution.
10 * Copyright (c) The Exim Maintainers 2015 - 2016
13 /* This patch is based on code from Tom Kistners exiscan (ACL integration) and
14 * the DCC local_scan patch from Christopher Bodenstein */
16 /* Code for calling dccifd. Called from acl.c. */
19 #ifdef EXPERIMENTAL_DCC
23 uschar dcc_header_str[256];
27 /* This function takes a file descriptor and a buffer as input and
28 * returns either 0 for success or errno in case of error. */
30 int flushbuffer (int socket, uschar *buffer)
33 rsp = write(socket, buffer, Ustrlen(buffer));
35 debug_printf("DCC: Result of the write() = %d\n", rsp);
39 debug_printf("DCC: Error writing buffer to socket: %s\n", strerror(errno));
44 debug_printf("DCC: Wrote buffer to socket:\n%s\n", buffer);
51 dcc_process(uschar **listptr)
54 const uschar *list = *listptr;
56 uschar *dcc_default_ip_option = US"127.0.0.1";
57 uschar *dcc_helo_option = US"localhost";
58 uschar *dcc_reject_message = US"Rejected by DCC";
59 uschar *xtra_hdrs = NULL;
60 uschar *override_client_ip = NULL;
63 int i, j, k, c, retval, sockfd, resp, line;
65 struct sockaddr_un serv_addr;
66 struct sockaddr_in serv_addr_in;
67 struct hostent *ipaddress;
69 uschar sockip[40], client_ip[40];
71 uschar rcpt[128], from[128];
74 uschar dcc_return_text[1024];
75 uschar message_subdir[2];
76 struct header_line *dcchdr;
77 uschar *dcc_acl_options;
78 uschar dcc_acl_options_buffer[10];
79 uschar dcc_xtra_hdrs[1024];
82 if ((dcc_acl_options = string_nextinlist(&list, &sep,
83 dcc_acl_options_buffer, sizeof(dcc_acl_options_buffer))))
85 /* parse 1st option */
86 if ( strcmpic(dcc_acl_options, US"false") == 0
87 || Ustrcmp(dcc_acl_options, "0") == 0
89 return FAIL; /* explicitly no matching */
92 return FAIL; /* empty means "don't match anything" */
96 /* if we scanned this message last time, just return */
100 /* open the spooled body */
101 message_subdir[1] = '\0';
102 for (i = 0; i < 2; i++)
104 message_subdir[0] = split_spool_directory == (i == 0) ? message_id[5] : 0;
106 if ((data_file = Ufopen(
107 spool_fname(US"input", message_subdir, message_id, US"-D"),
114 /* error while spooling */
115 log_write(0, LOG_MAIN|LOG_PANIC,
116 "dcc acl condition: error while opening spool file");
120 /* Initialize the variables */
122 bzero(sockip,sizeof(sockip));
123 if (dccifd_address) {
124 if (dccifd_address[0] == '/')
125 Ustrncpy(sockpath, dccifd_address, sizeof(sockpath));
127 if( sscanf(CS dccifd_address, "%s %u", sockip, &portnr) != 2) {
128 log_write(0, LOG_MAIN,
129 "dcc acl condition: warning - invalid dccifd address: '%s'", dccifd_address);
130 (void)fclose(data_file);
135 /* opts is what we send as dccifd options - see man dccifd */
136 /* We don't support any other option than 'header' so just copy that */
137 bzero(opts,sizeof(opts));
138 Ustrncpy(opts, dccifd_options, sizeof(opts)-1);
139 /* if $acl_m_dcc_override_client_ip is set use it */
140 if (((override_client_ip = expand_string(US"$acl_m_dcc_override_client_ip")) != NULL) &&
141 (override_client_ip[0] != '\0')) {
142 Ustrncpy(client_ip, override_client_ip, sizeof(client_ip)-1);
144 debug_printf("DCC: Client IP (overridden): %s\n", client_ip);
146 else if(sender_host_address) {
147 /* else if $sender_host_address is available use that? */
148 Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
150 debug_printf("DCC: Client IP (sender_host_address): %s\n", client_ip);
153 /* sender_host_address is NULL which means it comes from localhost */
154 Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
156 debug_printf("DCC: Client IP (default): %s\n", client_ip);
158 /* strncat(opts, my_request, strlen(my_request)); */
160 Ustrncat(opts, client_ip, sizeof(opts)-Ustrlen(opts)-1);
161 Ustrncat(opts, "\nHELO ", sizeof(opts)-Ustrlen(opts)-1);
162 Ustrncat(opts, dcc_helo_option, sizeof(opts)-Ustrlen(opts)-2);
165 /* initialize the other variables */
166 dcchdr = header_list;
167 /* we set the default return value to DEFER */
170 bzero(sendbuf,sizeof(sendbuf));
171 bzero(dcc_header_str,sizeof(dcc_header_str));
172 bzero(rcpt,sizeof(rcpt));
173 bzero(from,sizeof(from));
175 /* send a null return path as "<>". */
176 if (Ustrlen(sender_address) > 0)
177 Ustrncpy(from, sender_address, sizeof(from));
179 Ustrncpy(from, "<>", sizeof(from));
180 Ustrncat(from, "\n", sizeof(from)-Ustrlen(from)-1);
182 /**************************************
183 * Now creating the socket connection *
184 **************************************/
186 /* If sockip contains an ip, we use a tcp socket, otherwise a UNIX socket */
187 if(Ustrcmp(sockip, "")){
188 ipaddress = gethostbyname(CS sockip);
189 bzero(CS &serv_addr_in, sizeof(serv_addr_in));
190 serv_addr_in.sin_family = AF_INET;
191 bcopy(CS ipaddress->h_addr, CS &serv_addr_in.sin_addr.s_addr, ipaddress->h_length);
192 serv_addr_in.sin_port = htons(portnr);
193 if ((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){
195 debug_printf("DCC: Creating TCP socket connection failed: %s\n", strerror(errno));
196 log_write(0,LOG_PANIC,"DCC: Creating TCP socket connection failed: %s\n", strerror(errno));
197 /* if we cannot create the socket, defer the mail */
198 (void)fclose(data_file);
201 /* Now connecting the socket (INET) */
202 if (connect(sockfd, (struct sockaddr *)&serv_addr_in, sizeof(serv_addr_in)) < 0){
204 debug_printf("DCC: Connecting to TCP socket failed: %s\n", strerror(errno));
205 log_write(0,LOG_PANIC,"DCC: Connecting to TCP socket failed: %s\n", strerror(errno));
206 /* if we cannot contact the socket, defer the mail */
207 (void)fclose(data_file);
211 /* connecting to the dccifd UNIX socket */
212 bzero(&serv_addr, sizeof(serv_addr));
213 serv_addr.sun_family = AF_UNIX;
214 Ustrncpy(serv_addr.sun_path, sockpath, sizeof(serv_addr.sun_path));
215 if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0){
217 debug_printf("DCC: Creating UNIX socket connection failed: %s\n", strerror(errno));
218 log_write(0,LOG_PANIC,"DCC: Creating UNIX socket connection failed: %s\n", strerror(errno));
219 /* if we cannot create the socket, defer the mail */
220 (void)fclose(data_file);
223 /* Now connecting the socket (UNIX) */
224 if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0){
226 debug_printf("DCC: Connecting to UNIX socket failed: %s\n", strerror(errno));
227 log_write(0,LOG_PANIC,"DCC: Connecting to UNIX socket failed: %s\n", strerror(errno));
228 /* if we cannot contact the socket, defer the mail */
229 (void)fclose(data_file);
233 /* the socket is open, now send the options to dccifd*/
235 debug_printf("\nDCC: ---------------------------\nDCC: Socket opened; now sending input\nDCC: -----------------\n");
236 /* First, fill in the input buffer */
237 Ustrncpy(sendbuf, opts, sizeof(sendbuf));
238 Ustrncat(sendbuf, from, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
242 debug_printf("DCC: opts = %s\nDCC: sender = %s\nDCC: rcpt count = %d\n", opts, from, recipients_count);
243 debug_printf("DCC: Sending options:\nDCC: ****************************\n");
246 /* let's send each of the recipients to dccifd */
247 for (i = 0; i < recipients_count; i++){
249 debug_printf("DCC: recipient = %s\n",recipients_list[i].address);
250 if(Ustrlen(sendbuf) + Ustrlen(recipients_list[i].address) > sizeof(sendbuf))
253 debug_printf("DCC: Writing buffer: %s\n", sendbuf);
254 flushbuffer(sockfd, sendbuf);
255 bzero(sendbuf, sizeof(sendbuf));
257 Ustrncat(sendbuf, recipients_list[i].address, sizeof(sendbuf)-Ustrlen(sendbuf)-1);
258 Ustrncat(sendbuf, "\r\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
260 /* send a blank line between options and message */
261 Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
262 /* Now we send the input buffer */
264 debug_printf("DCC: %s\nDCC: ****************************\n", sendbuf);
265 flushbuffer(sockfd, sendbuf);
267 /* now send the message */
268 /* Clear the input buffer */
269 bzero(sendbuf, sizeof(sendbuf));
270 /* First send the headers */
271 /* Now send the headers */
273 debug_printf("DCC: Sending headers:\nDCC: ****************************\n");
274 Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
275 while((dcchdr=dcchdr->next)) {
276 if(dcchdr->slen > sizeof(sendbuf)-2) {
277 /* The size of the header is bigger than the size of
278 * the input buffer, so split it up in smaller parts. */
279 flushbuffer(sockfd, sendbuf);
280 bzero(sendbuf, sizeof(sendbuf));
282 while(j < dcchdr->slen)
284 for(i = 0; i < sizeof(sendbuf)-2; i++) {
285 sendbuf[i] = dcchdr->text[j];
288 flushbuffer(sockfd, sendbuf);
289 bzero(sendbuf, sizeof(sendbuf));
291 } else if(Ustrlen(sendbuf) + dcchdr->slen > sizeof(sendbuf)-2) {
292 flushbuffer(sockfd, sendbuf);
293 bzero(sendbuf, sizeof(sendbuf));
294 Ustrncpy(sendbuf, dcchdr->text, sizeof(sendbuf)-2);
296 Ustrncat(sendbuf, dcchdr->text, sizeof(sendbuf)-Ustrlen(sendbuf)-2);
300 /* a blank line separates header from body */
301 Ustrncat(sendbuf, "\n", sizeof(sendbuf)-Ustrlen(sendbuf)-1);
302 flushbuffer(sockfd, sendbuf);
304 debug_printf("\nDCC: ****************************\n%s", sendbuf);
306 /* Clear the input buffer */
307 bzero(sendbuf, sizeof(sendbuf));
309 /* now send the body */
311 debug_printf("DCC: Writing body:\nDCC: ****************************\n");
312 (void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);
313 while((fread(sendbuf, 1, sizeof(sendbuf)-1, data_file)) > 0) {
314 flushbuffer(sockfd, sendbuf);
315 bzero(sendbuf, sizeof(sendbuf));
318 debug_printf("\nDCC: ****************************\n");
320 /* shutdown() the socket */
321 if(shutdown(sockfd, 1) < 0){
323 debug_printf("DCC: Couldn't shutdown socket: %s\n", strerror(errno));
324 log_write(0,LOG_MAIN,"DCC: Couldn't shutdown socket: %s\n", strerror(errno));
325 /* If there is a problem with the shutdown()
327 (void)fclose(data_file);
331 debug_printf("\nDCC: -------------------------\nDCC: Input sent.\nDCC: -------------------------\n");
333 /********************************
334 * receiving output from dccifd *
335 ********************************/
337 debug_printf("\nDCC: -------------------------------------\nDCC: Now receiving output from server\nDCC: -----------------------------------\n");
339 /******************************************************************
340 * We should get 3 lines: *
341 * 1/ First line is overall result: either 'A' for Accept, *
342 * 'R' for Reject, 'S' for accept Some recipients or *
343 * 'T' for a Temporary error. *
344 * 2/ Second line contains the list of Accepted/Rejected *
345 * recipients in the form AARRA (A = accepted, R = rejected). *
346 * 3/ Third line contains the X-DCC header. *
347 ******************************************************************/
349 line = 1; /* we start at the first line of the output */
350 j = 0; /* will be used as index for the recipients list */
351 k = 0; /* initializing the index of the X-DCC header: dcc_header_str[k] */
353 /* Let's read from the socket until there's nothing left to read */
354 bzero(recvbuf, sizeof(recvbuf));
355 while((resp = read(sockfd, recvbuf, sizeof(recvbuf)-1)) > 0) {
356 /* How much did we get from the socket */
357 c = Ustrlen(recvbuf) + 1;
359 debug_printf("DCC: Length of the output buffer is: %d\nDCC: Output buffer is:\nDCC: ------------\nDCC: %s\nDCC: -----------\n", c, recvbuf);
361 /* Now let's read each character and see what we've got */
362 for(i = 0; i < c; i++) {
363 /* First check if we reached the end of the line and
364 * then increment the line counter */
365 if(recvbuf[i] == '\n') {
369 /* The first character of the first line is the
370 * overall response. If there's another character
371 * on that line it is not correct. */
374 /* Now get the value and set the
375 * return value accordingly */
376 if(recvbuf[i] == 'A') {
378 debug_printf("DCC: Overall result = A\treturning OK\n");
379 Ustrcpy(dcc_return_text, "Mail accepted by DCC");
383 else if(recvbuf[i] == 'R') {
385 debug_printf("DCC: Overall result = R\treturning FAIL\n");
388 if(sender_host_name) {
389 log_write(0, LOG_MAIN, "H=%s [%s] F=<%s>: rejected by DCC", sender_host_name, sender_host_address, sender_address);
392 log_write(0, LOG_MAIN, "H=[%s] F=<%s>: rejected by DCC", sender_host_address, sender_address);
394 Ustrncpy(dcc_return_text, dcc_reject_message, Ustrlen(dcc_reject_message) + 1);
396 else if(recvbuf[i] == 'S') {
398 debug_printf("DCC: Overall result = S\treturning OK\n");
399 Ustrcpy(dcc_return_text, "Not all recipients accepted by DCC");
400 /* Since we're in an ACL we want a global result
401 * so we accept for all */
405 else if(recvbuf[i] == 'G') {
407 debug_printf("DCC: Overall result = G\treturning FAIL\n");
408 Ustrcpy(dcc_return_text, "Greylisted by DCC");
412 else if(recvbuf[i] == 'T') {
414 debug_printf("DCC: Overall result = T\treturning DEFER\n");
416 log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", recvbuf);
417 Ustrcpy(dcc_return_text, "Temporary error with DCC");
422 debug_printf("DCC: Overall result = something else\treturning DEFER\n");
424 log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", recvbuf);
425 Ustrcpy(dcc_return_text, "Unknown DCC response");
430 /* We're on the first line but not on the first character,
431 * there must be something wrong. */
432 DEBUG(D_acl) debug_printf("DCC: Line = %d but i = %d != 0"
433 " character is %c - This is wrong!\n", line, i, recvbuf[i]);
434 log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", recvbuf);
438 /* On the second line we get a list of
439 * answers for each recipient. We don't care about
440 * it because we're in an acl and take the
444 /* The third and following lines are the X-DCC header,
445 * so we store it in dcc_header_str. */
446 /* check if we don't get more than we can handle */
447 if(k < sizeof(dcc_header_str)) {
448 dcc_header_str[k] = recvbuf[i];
452 DEBUG(D_acl) debug_printf("DCC: We got more output than we can store"
453 " in the X-DCC header. Truncating at 120 characters.\n");
457 /* Wrong line number. There must be a problem with the output. */
459 debug_printf("DCC: Wrong line number in output. Line number is %d\n", line);
463 /* we reinitialize the output buffer before we read again */
464 bzero(recvbuf,sizeof(recvbuf));
466 /* We have read everything from the socket */
468 /* We need to terminate the X-DCC header with a '\n' character. This needs to be k-1
469 * since dcc_header_str[k] contains '\0'. */
470 dcc_header_str[k-1] = '\n';
472 /* Now let's sum up what we've got. */
474 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);
476 /* We only add the X-DCC header if it starts with X-DCC */
477 if(!(Ustrncmp(dcc_header_str, "X-DCC", 5))){
478 dcc_header = dcc_header_str;
479 if(dcc_direct_add_header) {
480 header_add(' ' , "%s", dcc_header_str);
481 /* since the MIME ACL already writes the .eml file to disk without DCC Header we've to erase it */
487 debug_printf("DCC: Wrong format of the X-DCC header: %s\n", dcc_header_str);
490 /* check if we should add additional headers passed in acl_m_dcc_add_header */
491 if(dcc_direct_add_header) {
492 if (((xtra_hdrs = expand_string(US"$acl_m_dcc_add_header")) != NULL) && (xtra_hdrs[0] != '\0')) {
493 Ustrncpy(dcc_xtra_hdrs, xtra_hdrs, sizeof(dcc_xtra_hdrs) - 2);
494 if (dcc_xtra_hdrs[Ustrlen(dcc_xtra_hdrs)-1] != '\n')
495 Ustrcat(dcc_xtra_hdrs, "\n");
496 header_add(' ', "%s", dcc_xtra_hdrs);
498 debug_printf("DCC: adding additional headers in $acl_m_dcc_add_header: %s", dcc_xtra_hdrs);
503 /* Now return to exim main process */
505 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);
507 (void)fclose(data_file);