regex support for MIME and DATA ACLs

diff --git a/src/src/regex.c b/src/src/regex.c
new file mode 100644 (file)
index 0000000..760910a
--- /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 <tom@duncanthrax.net> 2003-???? */
+/* License: GPL */
+
+/* Code for matching regular expressions against headers and body.
+ Called from acl.c. */
+
+#include "exim.h"
+#include <unistd.h>
+#include <sys/mman.h>
+
+/* 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;
+}
+