diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:16:13 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:16:13 +0000 |
commit | e90fcc54809db2591dc083f43ef54c6ec8c60847 (patch) | |
tree | f20bc206c3c2d5d59d37c46c5cf5d53a20642556 /src/dcc.c | |
parent | Initial commit. (diff) | |
download | exim4-e90fcc54809db2591dc083f43ef54c6ec8c60847.tar.xz exim4-e90fcc54809db2591dc083f43ef54c6ec8c60847.zip |
Adding upstream version 4.96.upstream/4.96upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/dcc.c | 490 |
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 |