From: Tom Kistner Date: Fri, 26 Nov 2004 09:24:05 +0000 (+0000) Subject: regex support for MIME and DATA ACLs X-Git-Url: https://git.exim.org/users/jgh/exim.git/commitdiff_plain/26f6e9a5700c9e2b86a3996da16393c7c7b016dc regex support for MIME and DATA ACLs --- diff --git a/src/src/regex.c b/src/src/regex.c new file mode 100644 index 000000000..760910a74 --- /dev/null +++ b/src/src/regex.c @@ -0,0 +1,248 @@ +/* $Cambridge: exim/src/src/regex.c,v 1.1.2.1 2004/11/26 09:24:05 tom Exp $ */ + +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* This file is part of the exiscan-acl content scanner +patch. It is NOT part of the standard exim distribution. */ + +/* Copyright (c) Tom Kistner 2003-???? */ +/* License: GPL */ + +/* Code for matching regular expressions against headers and body. + Called from acl.c. */ + +#include "exim.h" +#include +#include + +/* Structure to hold a list of Regular expressions */ +typedef struct pcre_list { + pcre *re; + uschar *pcre_text; + struct pcre_list *next; +} pcre_list; + +uschar regex_match_string_buffer[1024]; + +extern FILE *mime_stream; +extern uschar *mime_current_boundary; + +int regex(uschar **listptr) { + int sep = 0; + uschar *list = *listptr; + uschar *regex_string; + uschar regex_string_buffer[1024]; + unsigned long long mbox_size; + FILE *mbox_file; + pcre *re; + pcre_list *re_list_head = NULL; + pcre_list *re_list_item; + const char *pcre_error; + int pcre_erroffset; + uschar *linebuffer; + long f_pos = 0; + + /* reset expansion variable */ + regex_match_string = NULL; + + if (mime_stream == NULL) { + /* We are in the DATA ACL */ + mbox_file = spool_mbox(&mbox_size); + if (mbox_file == NULL) { + /* error while spooling */ + log_write(0, LOG_MAIN|LOG_PANIC, + "regex acl condition: error while creating mbox spool file"); + return DEFER; + }; + } + else { + f_pos = ftell(mime_stream); + mbox_file = mime_stream; + }; + + /* precompile our regexes */ + while ((regex_string = string_nextinlist(&list, &sep, + regex_string_buffer, + sizeof(regex_string_buffer))) != NULL) { + + /* parse option */ + if ( (strcmpic(regex_string,US"false") == 0) || + (Ustrcmp(regex_string,"0") == 0) ) { + /* explicitly no matching */ + continue; + }; + + /* compile our regular expression */ + re = pcre_compile( CS regex_string, + 0, + &pcre_error, + &pcre_erroffset, + NULL ); + + if (re == NULL) { + log_write(0, LOG_MAIN, + "regex acl condition warning - error in regex '%s': %s at offset %d, skipped.", regex_string, pcre_error, pcre_erroffset); + continue; + } + else { + re_list_item = store_get(sizeof(pcre_list)); + re_list_item->re = re; + re_list_item->pcre_text = string_copy(regex_string); + re_list_item->next = re_list_head; + re_list_head = re_list_item; + }; + }; + + /* no regexes -> nothing to do */ + if (re_list_head == NULL) { + return FAIL; + }; + + /* match each line against all regexes */ + linebuffer = store_get(32767); + while (fgets(CS linebuffer, 32767, mbox_file) != NULL) { + if ( (mime_stream != NULL) && (mime_current_boundary != NULL) ) { + /* check boundary */ + if (Ustrncmp(linebuffer,"--",2) == 0) { + if (Ustrncmp((linebuffer+2),mime_current_boundary,Ustrlen(mime_current_boundary)) == 0) + /* found boundary */ + break; + }; + }; + re_list_item = re_list_head; + do { + /* try matcher on the line */ + if (pcre_exec(re_list_item->re, NULL, CS linebuffer, + (int)Ustrlen(linebuffer), 0, 0, NULL, 0) >= 0) { + Ustrncpy(regex_match_string_buffer, re_list_item->pcre_text, 1023); + regex_match_string = regex_match_string_buffer; + if (mime_stream == NULL) + fclose(mbox_file); + else { + clearerr(mime_stream); + fseek(mime_stream,f_pos,SEEK_SET); + }; + return OK; + }; + re_list_item = re_list_item->next; + } while (re_list_item != NULL); + }; + + if (mime_stream == NULL) + fclose(mbox_file); + else { + clearerr(mime_stream); + fseek(mime_stream,f_pos,SEEK_SET); + }; + + /* no matches ... */ + return FAIL; +} + + +int mime_regex(uschar **listptr) { + int sep = 0; + uschar *list = *listptr; + uschar *regex_string; + uschar regex_string_buffer[1024]; + pcre *re; + pcre_list *re_list_head = NULL; + pcre_list *re_list_item; + const char *pcre_error; + int pcre_erroffset; + FILE *f; + uschar *mime_subject = NULL; + int mime_subject_len = 0; + + /* reset expansion variable */ + regex_match_string = NULL; + + /* precompile our regexes */ + while ((regex_string = string_nextinlist(&list, &sep, + regex_string_buffer, + sizeof(regex_string_buffer))) != NULL) { + + /* parse option */ + if ( (strcmpic(regex_string,US"false") == 0) || + (Ustrcmp(regex_string,"0") == 0) ) { + /* explicitly no matching */ + continue; + }; + + /* compile our regular expression */ + re = pcre_compile( CS regex_string, + 0, + &pcre_error, + &pcre_erroffset, + NULL ); + + if (re == NULL) { + log_write(0, LOG_MAIN, + "regex acl condition warning - error in regex '%s': %s at offset %d, skipped.", regex_string, pcre_error, pcre_erroffset); + continue; + } + else { + re_list_item = store_get(sizeof(pcre_list)); + re_list_item->re = re; + re_list_item->pcre_text = string_copy(regex_string); + re_list_item->next = re_list_head; + re_list_head = re_list_item; + }; + }; + + /* no regexes -> nothing to do */ + if (re_list_head == NULL) { + return FAIL; + }; + + /* check if the file is already decoded */ + if (mime_decoded_filename == NULL) { + uschar *empty = US""; + /* no, decode it first */ + mime_decode(&empty); + if (mime_decoded_filename == NULL) { + /* decoding failed */ + log_write(0, LOG_MAIN, + "mime_regex acl condition warning - could not decode MIME part to file."); + return DEFER; + }; + }; + + + /* open file */ + f = fopen(CS mime_decoded_filename, "r"); + if (f == NULL) { + /* open failed */ + log_write(0, LOG_MAIN, + "mime_regex acl condition warning - can't open '%s' for reading.", mime_decoded_filename); + return DEFER; + }; + + /* get 32k memory */ + mime_subject = (uschar *)store_get(32767); + + /* read max 32k chars from file */ + mime_subject_len = fread(mime_subject, 1, 32766, f); + + re_list_item = re_list_head; + do { + /* try matcher on the mmapped file */ + debug_printf("Matching '%s'\n", re_list_item->pcre_text); + if (pcre_exec(re_list_item->re, NULL, CS mime_subject, + mime_subject_len, 0, 0, NULL, 0) >= 0) { + Ustrncpy(regex_match_string_buffer, re_list_item->pcre_text, 1023); + regex_match_string = regex_match_string_buffer; + fclose(f); + return OK; + }; + re_list_item = re_list_item->next; + } while (re_list_item != NULL); + + fclose(f); + + /* no matches ... */ + return FAIL; +} +