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-rw-r--r--src/dcc.c490
1 files changed, 490 insertions, 0 deletions
diff --git a/src/dcc.c b/src/dcc.c
new file mode 100644
index 0000000..a9124a0
--- /dev/null
+++ b/src/dcc.c
@@ -0,0 +1,490 @@
+/*************************************************
+* Exim - an Internet mail transport agent *
+*************************************************/
+
+/* Copyright (c) Wolfgang Breyha 2005 - 2019
+ * Vienna University Computer Center
+ * wbreyha@gmx.net
+ * See the file NOTICE for conditions of use and distribution.
+ *
+ * Copyright (c) The Exim Maintainers 2015 - 2021
+ */
+
+/* Code for calling dccifd. Called from acl.c. */
+
+#include "exim.h"
+#ifdef EXPERIMENTAL_DCC
+#include "dcc.h"
+#include "unistd.h"
+
+#define DCC_HEADER_LIMIT 120
+
+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. */
+
+static int flushbuffer
+(int socket, gstring *buffer)
+{
+int rsp;
+
+rsp = write(socket, buffer->s, buffer->ptr);
+DEBUG(D_acl)
+ debug_printf("DCC: flushbuffer(): Result of the write() = %d\n", rsp);
+if(rsp < 0)
+ {
+ DEBUG(D_acl)
+ debug_printf("DCC: flushbuffer(): Error writing buffer to socket: %s\n", strerror(errno));
+ return errno;
+ }
+DEBUG(D_acl)
+ debug_printf("DCC: flushbuffer(): Wrote buffer to socket:\n%.*s\n", buffer->ptr, buffer->s);
+return 0;
+}
+
+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 *xtra_hdrs = NULL;
+uschar *override_client_ip = NULL;
+
+/* from local_scan */
+int dcc_resplen, retval, sockfd, resp;
+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];
+gstring *dcc_headers;
+gstring *sendbuf;
+uschar *dcc_return_text = US"''";
+struct header_line *mail_headers;
+uschar *dcc_acl_options;
+gstring *dcc_xtra_hdrs;
+gstring *dcc_header_str;
+
+/* grep 1st option */
+if ((dcc_acl_options = string_nextinlist(&list, &sep, NULL, 0)))
+ {
+ /* 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 */
+for (int i = 0; i < 2; i++)
+ {
+ uschar message_subdir[2];
+ set_subdir_str(message_subdir, message_id, i);
+ 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: 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: warning - invalid dccifd address: '%s'", dccifd_address);
+ (void)fclose(data_file);
+ return DEFER;
+ }
+ }
+
+/* dcc_headers is what we send as dccifd options - see man dccifd */
+/* We don't support any other option than 'header' so just copy that */
+dcc_headers = string_cat(NULL, dccifd_options);
+/* 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);
+ }
+/* build options block */
+dcc_headers = string_append(dcc_headers, 5, US"\n", client_ip, US"\nHELO ", dcc_helo_option, US"\n");
+
+/* initialize the other variables */
+mail_headers = header_list;
+/* we set the default return value to DEFER */
+retval = DEFER;
+
+/* send a null return path as "<>". */
+dcc_headers = string_cat (dcc_headers, *sender_address ? sender_address : US"<>");
+dcc_headers = string_catn(dcc_headers, US"\n", 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(US 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("DCC: -----------------------------------\nDCC: Socket opened; now sending input\n"
+ "DCC: -----------------------------------\n");
+
+/* let's send each of the recipients to dccifd */
+for (int i = 0; i < recipients_count; i++)
+ {
+ DEBUG(D_acl)
+ debug_printf("DCC: recipient = %s\n",recipients_list[i].address);
+ dcc_headers = string_append(dcc_headers, 2, recipients_list[i].address, "\n");
+ }
+/* send a blank line between options and message */
+dcc_headers = string_catn(dcc_headers, US"\n", 1);
+/* Now we send the input buffer */
+(void) string_from_gstring(dcc_headers);
+DEBUG(D_acl)
+ debug_printf("DCC: ***********************************\nDCC: Sending options:\n%s"
+ "DCC: ***********************************\n", dcc_headers->s);
+if (flushbuffer(sockfd, dcc_headers) != 0)
+ {
+ (void)fclose(data_file);
+ return retval;
+ }
+
+/* now send the message */
+/* First send the headers */
+DEBUG(D_acl)
+ debug_printf("DCC: ***********************************\nDCC: Sending headers:\n");
+sendbuf = string_get(8192);
+sendbuf = string_catn(sendbuf, mail_headers->text, mail_headers->slen);
+while((mail_headers=mail_headers->next))
+ sendbuf = string_catn(sendbuf, mail_headers->text, mail_headers->slen);
+
+/* a blank line separates header from body */
+sendbuf = string_catn(sendbuf, US"\r\n", 2);
+(void) string_from_gstring(sendbuf);
+gstring_release_unused(sendbuf);
+DEBUG(D_acl)
+ debug_printf("%sDCC: ***********************************\n", sendbuf->s);
+if (flushbuffer(sockfd, sendbuf) != 0)
+ {
+ (void)fclose(data_file);
+ return retval;
+ }
+
+/* now send the body */
+DEBUG(D_acl)
+ debug_printf("DCC: ***********************************\nDCC: Writing body:\n");
+(void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);
+
+gstring filebuf = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
+
+while((filebuf.ptr = fread(filebuf.s, 1, filebuf.size, data_file)) > 0)
+ if (flushbuffer(sockfd, &filebuf) != 0)
+ {
+ (void)fclose(data_file);
+ return retval;
+ }
+DEBUG(D_acl)
+ debug_printf("DCC: ***********************************\n");
+
+/* shutdown() the socket */
+if(shutdown(sockfd, SHUT_WR) < 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("DCC: Input sent.\n"
+ "DCC: +++++++++++++++++++++++++++++++++++\n"
+ "DCC: Now receiving output from server\n"
+ "DCC: -----------------------------------\n");
+
+/********************************
+ * receiving output from dccifd *
+ ********************************/
+
+/******************************************************************
+ * 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. *
+ ******************************************************************/
+
+int line = 1; /* we start at the first line of the output */
+int bufoffset;
+
+dcc_header_str = string_get(DCC_HEADER_LIMIT + 2);
+/* Let's read from the socket until there's nothing left to read */
+while((dcc_resplen = read(sockfd, big_buffer, big_buffer_size-1)) > 0)
+ {
+ /* fail on read error */
+ if(dcc_resplen < 0)
+ {
+ DEBUG(D_acl)
+ debug_printf("DCC: Error reading from socket: %s\n", strerror(errno));
+ (void)fclose(data_file);
+ return retval;
+ }
+ /* make the answer 0-terminated. only needed for debug_printf */
+ DEBUG(D_acl)
+ debug_printf("DCC: Length of the output buffer is: %d\nDCC: Output buffer is:\n"
+ "DCC: -----------------------------------\n%.*s\n"
+ "DCC: -----------------------------------\n", dcc_resplen, dcc_resplen, big_buffer);
+
+ /* Now let's read each character and see what we've got */
+ for(bufoffset = 0; bufoffset < dcc_resplen && line <= 2; bufoffset++)
+ {
+ /* First check if we reached the end of the line and
+ then increment the line counter */
+ if(big_buffer[bufoffset] == '\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(bufoffset == 0)
+ {
+ /* Now get the value and set the return value accordingly */
+ switch (big_buffer[bufoffset])
+ {
+ case 'A':
+ DEBUG(D_acl)
+ debug_printf("DCC: Overall result = A\treturning OK\n");
+ dcc_return_text = US"Mail accepted by DCC";
+ dcc_result = US"A";
+ retval = OK;
+ break;
+ case 'R':
+ DEBUG(D_acl)
+ debug_printf("DCC: Overall result = R\treturning FAIL\n");
+ dcc_return_text = US"Rejected by DCC";
+ 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);
+ break;
+ case 'S':
+ DEBUG(D_acl)
+ debug_printf("DCC: Overall result = S\treturning OK\n");
+ dcc_return_text = US"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;
+ break;
+ case 'G':
+ DEBUG(D_acl)
+ debug_printf("DCC: Overall result = G\treturning FAIL\n");
+ dcc_return_text = US"Greylisted by DCC";
+ dcc_result = US"G";
+ retval = FAIL;
+ break;
+ case 'T':
+ DEBUG(D_acl)
+ debug_printf("DCC: Overall result = T\treturning DEFER\n");
+ dcc_return_text = US"Temporary error with DCC";
+ dcc_result = US"T";
+ retval = DEFER;
+ log_write(0,LOG_MAIN,"Temporary error with DCC: %s\n", big_buffer);
+ break;
+ default:
+ DEBUG(D_acl)
+ debug_printf("DCC: Overall result = something else\treturning DEFER\n");
+ dcc_return_text = US"Unknown DCC response";
+ dcc_result = US"T";
+ retval = DEFER;
+ log_write(0,LOG_MAIN,"Unknown DCC response: %s\n", big_buffer);
+ break;
+ }
+ }
+ 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 bufoffset = %d != 0"
+ " character is %c - This is wrong!\n", line, bufoffset, big_buffer[bufoffset]);
+ log_write(0,LOG_MAIN,"Wrong header from DCC, output is %s\n", big_buffer);
+ }
+ }
+ 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. */
+ }
+ }
+ }
+ if(line > 2)
+ {
+ /* The third and following lines are the X-DCC header, so we store it in
+ dcc_header_str up to our limit. */
+ /* check if buffer contains the end of the header .."\n\n" and truncate it */
+ if ((big_buffer[dcc_resplen-1] == '\n') &&
+ (big_buffer[dcc_resplen-2] == '\n'))
+ dcc_resplen -= 2;
+ dcc_resplen -= bufoffset;
+ if (dcc_header_str->ptr + dcc_resplen > DCC_HEADER_LIMIT)
+ {
+ dcc_resplen = DCC_HEADER_LIMIT - dcc_header_str->ptr;
+ DEBUG(D_acl) debug_printf("DCC: We got more output than we can store"
+ "in the X-DCC header. Truncating at 120 characters.\n");
+ }
+ dcc_header_str = string_catn(dcc_header_str, &big_buffer[bufoffset], dcc_resplen);
+ }
+ }
+/* We have read everything from the socket. make sure the header ends with "\n" */
+dcc_header_str = string_catn(dcc_header_str, US"\n", 1);
+
+(void) string_from_gstring(dcc_header_str);
+/* Now let's sum up what we've got. */
+DEBUG(D_acl)
+ debug_printf("\nDCC: --------------------------\nDCC: Overall result = %d\n"
+ "DCC: X-DCC header: %sReturn message: %s\nDCC: dcc_result: %s\n",
+ retval, dcc_header_str->s, dcc_return_text, dcc_result);
+
+/* We only add the X-DCC header if it starts with X-DCC */
+if(!(Ustrncmp(dcc_header_str->s, "X-DCC", 5)))
+ {
+ dcc_header = dcc_header_str->s;
+ if(dcc_direct_add_header)
+ {
+ header_add(' ' , "%s", dcc_header_str->s);
+/* 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->ptr, dcc_header_str->s);
+
+/* 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'))
+ {
+ dcc_xtra_hdrs = string_cat(NULL, xtra_hdrs);
+ if (dcc_xtra_hdrs->s[dcc_xtra_hdrs->ptr - 1] != '\n')
+ dcc_xtra_hdrs = string_catn(dcc_xtra_hdrs, US"\n", 1);
+ header_add(' ', "%s", string_from_gstring(dcc_xtra_hdrs));
+ DEBUG(D_acl)
+ debug_printf("DCC: adding additional headers in $acl_m_dcc_add_header: %.*s", dcc_xtra_hdrs->ptr, dcc_xtra_hdrs->s);
+ }
+ }
+
+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\n"
+ "DCC: dcc_result = %s\n", dcc_return_text, retval, dcc_result);
+
+(void)fclose(data_file);
+dcc_rc = retval;
+return dcc_rc;
+}
+
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-03 07:13:05 +0000