1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) Wolfgang Breyha 2005 - 2019
6 * Vienna University Computer Center
8 * See the file NOTICE for conditions of use and distribution.
10 * Copyright (c) The Exim Maintainers 2015 - 2019
13 /* Code for calling dccifd. Called from acl.c. */
16 #ifdef EXPERIMENTAL_DCC
20 #define DCC_HEADER_LIMIT 120
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. */
28 static int flushbuffer
29 (int socket, gstring *buffer)
33 rsp = write(socket, buffer->s, buffer->ptr);
35 debug_printf("DCC: flushbuffer(): Result of the write() = %d\n", rsp);
39 debug_printf("DCC: flushbuffer(): Error writing buffer to socket: %s\n", strerror(errno));
43 debug_printf("DCC: flushbuffer(): Wrote buffer to socket:\n%.*s\n", buffer->ptr, buffer->s);
48 dcc_process(uschar **listptr)
51 const uschar *list = *listptr;
53 uschar *dcc_default_ip_option = US"127.0.0.1";
54 uschar *dcc_helo_option = US"localhost";
55 uschar *xtra_hdrs = NULL;
56 uschar *override_client_ip = NULL;
59 int dcc_resplen, retval, sockfd, resp;
61 struct sockaddr_un serv_addr;
62 struct sockaddr_in serv_addr_in;
63 struct hostent *ipaddress;
65 uschar sockip[40], client_ip[40];
68 uschar *dcc_return_text = US"''";
69 struct header_line *mail_headers;
70 uschar *dcc_acl_options;
71 gstring *dcc_xtra_hdrs;
72 gstring *dcc_header_str;
75 if ((dcc_acl_options = string_nextinlist(&list, &sep, NULL, 0)))
77 /* parse 1st option */
78 if ( strcmpic(dcc_acl_options, US"false") == 0
79 || Ustrcmp(dcc_acl_options, "0") == 0)
80 return FAIL; /* explicitly no matching */
83 return FAIL; /* empty means "don't match anything" */
87 /* if we scanned this message last time, just return */
91 /* open the spooled body */
92 for (int i = 0; i < 2; i++)
94 uschar message_subdir[2];
95 set_subdir_str(message_subdir, message_id, i);
96 if ((data_file = Ufopen(
97 spool_fname(US"input", message_subdir, message_id, US"-D"), "rb")))
103 /* error while spooling */
104 log_write(0, LOG_MAIN|LOG_PANIC,
105 "DCC: error while opening spool file");
109 /* Initialize the variables */
111 bzero(sockip,sizeof(sockip));
114 if (dccifd_address[0] == '/')
115 Ustrncpy(sockpath, dccifd_address, sizeof(sockpath));
117 if( sscanf(CS dccifd_address, "%s %u", sockip, &portnr) != 2)
119 log_write(0, LOG_MAIN,
120 "DCC: warning - invalid dccifd address: '%s'", dccifd_address);
121 (void)fclose(data_file);
126 /* dcc_headers is what we send as dccifd options - see man dccifd */
127 /* We don't support any other option than 'header' so just copy that */
128 dcc_headers = string_cat(NULL, dccifd_options);
129 /* if $acl_m_dcc_override_client_ip is set use it */
130 if (((override_client_ip = expand_string(US"$acl_m_dcc_override_client_ip")) != NULL) &&
131 (override_client_ip[0] != '\0'))
133 Ustrncpy(client_ip, override_client_ip, sizeof(client_ip)-1);
135 debug_printf("DCC: Client IP (overridden): %s\n", client_ip);
137 else if(sender_host_address)
139 /* else if $sender_host_address is available use that? */
140 Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
142 debug_printf("DCC: Client IP (sender_host_address): %s\n", client_ip);
146 /* sender_host_address is NULL which means it comes from localhost */
147 Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
149 debug_printf("DCC: Client IP (default): %s\n", client_ip);
151 /* build options block */
152 dcc_headers = string_append(dcc_headers, 5, US"\n", client_ip, US"\nHELO ", dcc_helo_option, US"\n");
154 /* initialize the other variables */
155 mail_headers = header_list;
156 /* we set the default return value to DEFER */
159 /* send a null return path as "<>". */
160 dcc_headers = string_cat (dcc_headers, *sender_address ? sender_address : US"<>");
161 dcc_headers = string_catn(dcc_headers, US"\n", 1);
163 /**************************************
164 * Now creating the socket connection *
165 **************************************/
167 /* If sockip contains an ip, we use a tcp socket, otherwise a UNIX socket */
168 if(Ustrcmp(sockip, ""))
170 ipaddress = gethostbyname(CS sockip);
171 bzero(CS &serv_addr_in, sizeof(serv_addr_in));
172 serv_addr_in.sin_family = AF_INET;
173 bcopy(CS ipaddress->h_addr, CS &serv_addr_in.sin_addr.s_addr, ipaddress->h_length);
174 serv_addr_in.sin_port = htons(portnr);
175 if ((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0)
178 debug_printf("DCC: Creating TCP socket connection failed: %s\n", strerror(errno));
179 log_write(0,LOG_PANIC,"DCC: Creating TCP socket connection failed: %s\n", strerror(errno));
180 /* if we cannot create the socket, defer the mail */
181 (void)fclose(data_file);
184 /* Now connecting the socket (INET) */
185 if (connect(sockfd, (struct sockaddr *)&serv_addr_in, sizeof(serv_addr_in)) < 0)
188 debug_printf("DCC: Connecting to TCP socket failed: %s\n", strerror(errno));
189 log_write(0,LOG_PANIC,"DCC: Connecting to TCP socket failed: %s\n", strerror(errno));
190 /* if we cannot contact the socket, defer the mail */
191 (void)fclose(data_file);
197 /* connecting to the dccifd UNIX socket */
198 bzero(&serv_addr, sizeof(serv_addr));
199 serv_addr.sun_family = AF_UNIX;
200 Ustrncpy(US serv_addr.sun_path, sockpath, sizeof(serv_addr.sun_path));
201 if ((sockfd = socket(AF_UNIX, SOCK_STREAM,0)) < 0)
204 debug_printf("DCC: Creating UNIX socket connection failed: %s\n", strerror(errno));
205 log_write(0,LOG_PANIC,"DCC: Creating UNIX socket connection failed: %s\n", strerror(errno));
206 /* if we cannot create the socket, defer the mail */
207 (void)fclose(data_file);
210 /* Now connecting the socket (UNIX) */
211 if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
214 debug_printf("DCC: Connecting to UNIX socket failed: %s\n", strerror(errno));
215 log_write(0,LOG_PANIC,"DCC: Connecting to UNIX socket failed: %s\n", strerror(errno));
216 /* if we cannot contact the socket, defer the mail */
217 (void)fclose(data_file);
221 /* the socket is open, now send the options to dccifd*/
223 debug_printf("DCC: -----------------------------------\nDCC: Socket opened; now sending input\n"
224 "DCC: -----------------------------------\n");
226 /* let's send each of the recipients to dccifd */
227 for (int i = 0; i < recipients_count; i++)
230 debug_printf("DCC: recipient = %s\n",recipients_list[i].address);
231 dcc_headers = string_append(dcc_headers, 2, recipients_list[i].address, "\n");
233 /* send a blank line between options and message */
234 dcc_headers = string_catn(dcc_headers, US"\n", 1);
235 /* Now we send the input buffer */
236 (void) string_from_gstring(dcc_headers);
238 debug_printf("DCC: ***********************************\nDCC: Sending options:\n%s"
239 "DCC: ***********************************\n", dcc_headers->s);
240 if (flushbuffer(sockfd, dcc_headers) != 0)
242 (void)fclose(data_file);
246 /* now send the message */
247 /* First send the headers */
249 debug_printf("DCC: ***********************************\nDCC: Sending headers:\n");
250 sendbuf = string_get(8192);
251 sendbuf = string_catn(sendbuf, mail_headers->text, mail_headers->slen);
252 while((mail_headers=mail_headers->next))
253 sendbuf = string_catn(sendbuf, mail_headers->text, mail_headers->slen);
255 /* a blank line separates header from body */
256 sendbuf = string_catn(sendbuf, US"\r\n", 2);
257 (void) string_from_gstring(sendbuf);
258 gstring_release_unused(sendbuf);
260 debug_printf("%sDCC: ***********************************\n", sendbuf->s);
261 if (flushbuffer(sockfd, sendbuf) != 0)
263 (void)fclose(data_file);
267 /* now send the body */
269 debug_printf("DCC: ***********************************\nDCC: Writing body:\n");
270 (void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);
272 gstring filebuf = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
274 while((filebuf.ptr = fread(filebuf.s, 1, filebuf.size, data_file)) > 0)
275 if (flushbuffer(sockfd, &filebuf) != 0)
277 (void)fclose(data_file);
281 debug_printf("DCC: ***********************************\n");
283 /* shutdown() the socket */
284 if(shutdown(sockfd, SHUT_WR) < 0)
287 debug_printf("DCC: Couldn't shutdown socket: %s\n", strerror(errno));
288 log_write(0,LOG_MAIN,"DCC: Couldn't shutdown socket: %s\n", strerror(errno));
289 /* If there is a problem with the shutdown()
291 (void)fclose(data_file);
295 debug_printf("DCC: Input sent.\n"
296 "DCC: +++++++++++++++++++++++++++++++++++\n"
297 "DCC: Now receiving output from server\n"
298 "DCC: -----------------------------------\n");
300 /********************************
301 * receiving output from dccifd *
302 ********************************/
304 /******************************************************************
305 * We should get 3 lines: *
306 * 1/ First line is overall result: either 'A' for Accept, *
307 * 'R' for Reject, 'S' for accept Some recipients or *
308 * 'T' for a Temporary error. *
309 * 2/ Second line contains the list of Accepted/Rejected *
310 * recipients in the form AARRA (A = accepted, R = rejected). *
311 * 3/ Third line contains the X-DCC header. *
312 ******************************************************************/
314 int line = 1; /* we start at the first line of the output */
317 dcc_header_str = string_get(DCC_HEADER_LIMIT + 2);
318 /* Let's read from the socket until there's nothing left to read */
319 while((dcc_resplen = read(sockfd, big_buffer, big_buffer_size-1)) > 0)
321 /* fail on read error */
325 debug_printf("DCC: Error reading from socket: %s\n", strerror(errno));
326 (void)fclose(data_file);
329 /* make the answer 0-terminated. only needed for debug_printf */
331 debug_printf("DCC: Length of the output buffer is: %d\nDCC: Output buffer is:\n"
332 "DCC: -----------------------------------\n%.*s\n"
333 "DCC: -----------------------------------\n", dcc_resplen, dcc_resplen, big_buffer);
335 /* Now let's read each character and see what we've got */
336 for(bufoffset = 0; bufoffset < dcc_resplen && line <= 2; bufoffset++)
338 /* First check if we reached the end of the line and
339 then increment the line counter */
340 if(big_buffer[bufoffset] == '\n')
344 /* The first character of the first line is the overall response. If
345 there's another character on that line it is not correct. */
350 /* Now get the value and set the return value accordingly */
351 switch (big_buffer[bufoffset])
355 debug_printf("DCC: Overall result = A\treturning OK\n");
356 dcc_return_text = US"Mail accepted by DCC";
362 debug_printf("DCC: Overall result = R\treturning FAIL\n");
363 dcc_return_text = US"Rejected by DCC";
367 log_write(0, LOG_MAIN, "H=%s [%s] F=<%s>: rejected by DCC",
368 sender_host_name, sender_host_address, sender_address);
370 log_write(0, LOG_MAIN, "H=[%s] F=<%s>: rejected by DCC",
371 sender_host_address, sender_address);
375 debug_printf("DCC: Overall result = S\treturning OK\n");
376 dcc_return_text = US"Not all recipients accepted by DCC";
377 /* Since we're in an ACL we want a global result so we accept for all */
383 debug_printf("DCC: Overall result = G\treturning FAIL\n");
384 dcc_return_text = US"Greylisted by DCC";
390 debug_printf("DCC: Overall result = T\treturning DEFER\n");
391 dcc_return_text = US"Temporary error with DCC";
394 log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", big_buffer);
398 debug_printf("DCC: Overall result = something else\treturning DEFER\n");
399 dcc_return_text = US"Unknown DCC response";
402 log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", big_buffer);
408 /* We're on the first line but not on the first character,
409 * there must be something wrong. */
410 DEBUG(D_acl) debug_printf("DCC: Line = %d but bufoffset = %d != 0"
411 " character is %c - This is wrong!\n", line, bufoffset, big_buffer[bufoffset]);
412 log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", big_buffer);
417 /* On the second line we get a list of answers for each recipient. We
418 don't care about it because we're in an acl and take the global result. */
424 /* The third and following lines are the X-DCC header, so we store it in
425 dcc_header_str up to our limit. */
426 /* check if buffer contains the end of the header .."\n\n" and truncate it */
427 if ((big_buffer[dcc_resplen-1] == '\n') &&
428 (big_buffer[dcc_resplen-2] == '\n'))
430 dcc_resplen -= bufoffset;
431 if (dcc_header_str->ptr + dcc_resplen > DCC_HEADER_LIMIT)
433 dcc_resplen = DCC_HEADER_LIMIT - dcc_header_str->ptr;
434 DEBUG(D_acl) debug_printf("DCC: We got more output than we can store"
435 "in the X-DCC header. Truncating at 120 characters.\n");
437 dcc_header_str = string_catn(dcc_header_str, &big_buffer[bufoffset], dcc_resplen);
440 /* We have read everything from the socket. make sure the header ends with "\n" */
441 dcc_header_str = string_catn(dcc_header_str, US"\n", 1);
443 (void) string_from_gstring(dcc_header_str);
444 /* Now let's sum up what we've got. */
446 debug_printf("\nDCC: --------------------------\nDCC: Overall result = %d\n"
447 "DCC: X-DCC header: %sReturn message: %s\nDCC: dcc_result: %s\n",
448 retval, dcc_header_str->s, dcc_return_text, dcc_result);
450 /* We only add the X-DCC header if it starts with X-DCC */
451 if(!(Ustrncmp(dcc_header_str->s, "X-DCC", 5)))
453 dcc_header = dcc_header_str->s;
454 if(dcc_direct_add_header)
456 header_add(' ' , "%s", dcc_header_str->s);
457 /* since the MIME ACL already writes the .eml file to disk without DCC Header we've to erase it */
463 debug_printf("DCC: Wrong format of the X-DCC header: %.*s\n", dcc_header_str->ptr, dcc_header_str->s);
465 /* check if we should add additional headers passed in acl_m_dcc_add_header */
466 if (dcc_direct_add_header)
468 if (((xtra_hdrs = expand_string(US"$acl_m_dcc_add_header")) != NULL) && (xtra_hdrs[0] != '\0'))
470 dcc_xtra_hdrs = string_cat(NULL, xtra_hdrs);
471 if (dcc_xtra_hdrs->s[dcc_xtra_hdrs->ptr - 1] != '\n')
472 dcc_xtra_hdrs = string_catn(dcc_xtra_hdrs, US"\n", 1);
473 header_add(' ', "%s", string_from_gstring(dcc_xtra_hdrs));
475 debug_printf("DCC: adding additional headers in $acl_m_dcc_add_header: %.*s", dcc_xtra_hdrs->ptr, dcc_xtra_hdrs->s);
480 /* Now return to exim main process */
482 debug_printf("DCC: Before returning to exim main process:\nDCC: return_text = %s - retval = %d\n"
483 "DCC: dcc_result = %s\n", dcc_return_text, retval, dcc_result);
485 (void)fclose(data_file);