/src/src/dcc.c
C | 519 lines | 374 code | 42 blank | 103 comment | 91 complexity | 612e351b304fc3714b3e8dc2b6705422 MD5 | raw file
Possible License(s): GPL-2.0
- /*************************************************
- * Exim - an Internet mail transport agent *
- *************************************************/
- /* Copyright (c) Wolfgang Breyha 2005-2013
- * Vienna University Computer Center
- * wbreyha@gmx.net
- * See the file NOTICE for conditions of use and distribution.
- */
- /* 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 mbox_path[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))) != NULL)
- {
- /* parse 1st option */
- if ( (strcmpic(dcc_acl_options,US"false") == 0) ||
- (Ustrcmp(dcc_acl_options,"0") == 0) ) {
- /* explicitly no matching */
- return FAIL;
- };
- /* special cases (match anything except empty) */
- if ( (strcmpic(dcc_acl_options,US"true") == 0) ||
- (Ustrcmp(dcc_acl_options,"*") == 0) ||
- (Ustrcmp(dcc_acl_options,"1") == 0) ) {
- dcc_acl_options = dcc_acl_options;
- };
- }
- else {
- /* empty means "don't match anything" */
- return FAIL;
- };
- 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;
- sprintf(CS mbox_path, "%s/input/%s/%s-D", spool_directory, message_subdir, message_id);
- data_file = Ufopen(mbox_path,"rb");
- if (data_file != NULL)
- break;
- };
- if (data_file == NULL) {
- /* 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((char *)sockip);
- bzero((char *) &serv_addr_in, sizeof(serv_addr_in));
- serv_addr_in.sin_family = AF_INET;
- bcopy((char *)ipaddress->h_addr, (char *)&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((char *)&serv_addr,sizeof(serv_addr));
- serv_addr.sun_family = AF_UNIX;
- Ustrcpy(serv_addr.sun_path, sockpath);
- 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 seperates 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