Adding upstream version 4.96.upstream/4.96upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 217 insertions, 0 deletions

diff --git a/src/regex.c b/src/regex.c
new file mode 100644
index 0000000..5c0f7c4
--- /dev/null
+++ b/src/regex.c
@@ -0,0 +1,217 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/*
+ * Copyright (c) The Exim Maintainers 2016 - 2022
+ * Copyright (c) Tom Kistner <tom@duncanthrax.net> 2003-2015
+ * License: GPL
+ */
+
+/* Code for matching regular expressions against headers and body.
+ Called from acl.c. */
+
+#include "exim.h"
+#ifdef WITH_CONTENT_SCAN
+#include <unistd.h>
+#include <sys/mman.h>
+
+/* Structure to hold a list of Regular expressions */
+typedef struct pcre_list {
+  pcre2_code *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;
+
+static pcre_list *
+compile(const uschar * list)
+{
+int sep = 0;
+uschar *regex_string;
+pcre_list *re_list_head = NULL;
+pcre_list *ri;
+
+/* precompile our regexes */
+while ((regex_string = string_nextinlist(&list, &sep, NULL, 0)))
+  if (strcmpic(regex_string, US"false") != 0 && Ustrcmp(regex_string, "0") != 0)
+    {
+    pcre2_code * re;
+    int err;
+    PCRE2_SIZE pcre_erroffset;
+
+    /* compile our regular expression */
+    if (!(re = pcre2_compile( (PCRE2_SPTR) regex_string, PCRE2_ZERO_TERMINATED,
+		  0, &err, &pcre_erroffset, pcre_cmp_ctx)))
+      {
+      uschar errbuf[128];
+      pcre2_get_error_message(err, errbuf, sizeof(errbuf));
+      log_write(0, LOG_MAIN,
+	   "regex acl condition warning - error in regex '%s': %s at offset %ld, skipped.",
+	   regex_string, errbuf, (long)pcre_erroffset);
+      continue;
+      }
+
+    ri = store_get(sizeof(pcre_list), GET_UNTAINTED);
+    ri->re = re;
+    ri->pcre_text = regex_string;
+    ri->next = re_list_head;
+    re_list_head = ri;
+    }
+return re_list_head;
+}
+
+static int
+matcher(pcre_list * re_list_head, uschar * linebuffer, int len)
+{
+pcre2_match_data * md = pcre2_match_data_create(REGEX_VARS + 1, pcre_gen_ctx);
+
+for (pcre_list * ri = re_list_head; ri; ri = ri->next)
+  {
+  int n;
+
+  /* try matcher on the line */
+  if ((n = pcre2_match(ri->re, (PCRE2_SPTR)linebuffer, len, 0, 0, md, pcre_mtc_ctx)) > 0)
+    {
+    Ustrncpy(regex_match_string_buffer, ri->pcre_text,
+	      sizeof(regex_match_string_buffer)-1);
+    regex_match_string = regex_match_string_buffer;
+
+    for (int nn = 1; nn < n; nn++)
+      {
+      PCRE2_UCHAR * cstr;
+      PCRE2_SIZE cslen;
+      pcre2_substring_get_bynumber(md, nn, &cstr, &cslen);
+      regex_vars[nn-1] = CUS cstr;
+      }
+
+    return OK;
+    }
+  }
+pcre2_match_data_free(md);
+return FAIL;
+}
+
+int
+regex(const uschar **listptr)
+{
+unsigned long mbox_size;
+FILE *mbox_file;
+pcre_list *re_list_head;
+uschar *linebuffer;
+long f_pos = 0;
+int ret = FAIL;
+
+/* reset expansion variable */
+regex_match_string = NULL;
+
+if (!mime_stream)				/* We are in the DATA ACL */
+  {
+  if (!(mbox_file = spool_mbox(&mbox_size, NULL, NULL)))
+    {						/* error while spooling */
+    log_write(0, LOG_MAIN|LOG_PANIC,
+	   "regex acl condition: error while creating mbox spool file");
+    return DEFER;
+    }
+  }
+else
+  {
+  if ((f_pos = ftell(mime_stream)) < 0)
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC,
+	   "regex acl condition: mime_stream: %s", strerror(errno));
+    return DEFER;
+    }
+  mbox_file = mime_stream;
+  }
+
+/* precompile our regexes */
+if (!(re_list_head = compile(*listptr)))
+  return FAIL;			/* no regexes -> nothing to do */
+
+/* match each line against all regexes */
+linebuffer = store_get(32767, GET_TAINTED);
+while (fgets(CS linebuffer, 32767, mbox_file))
+  {
+  if (  mime_stream && mime_current_boundary		/* check boundary */
+     && Ustrncmp(linebuffer, "--", 2) == 0
+     && Ustrncmp((linebuffer+2), mime_current_boundary,
+		  Ustrlen(mime_current_boundary)) == 0)
+      break;						/* found boundary */
+
+  if ((ret = matcher(re_list_head, linebuffer, (int)Ustrlen(linebuffer))) == OK)
+    goto done;
+  }
+/* no matches ... */
+
+done:
+if (!mime_stream)
+  (void)fclose(mbox_file);
+else
+  {
+  clearerr(mime_stream);
+  if (fseek(mime_stream, f_pos, SEEK_SET) == -1)
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC,
+	   "regex acl condition: mime_stream: %s", strerror(errno));
+    clearerr(mime_stream);
+    }
+  }
+
+return ret;
+}
+
+
+int
+mime_regex(const uschar **listptr)
+{
+pcre_list *re_list_head = NULL;
+FILE *f;
+uschar *mime_subject = NULL;
+int mime_subject_len = 0;
+int ret;
+
+/* reset expansion variable */
+regex_match_string = NULL;
+
+/* precompile our regexes */
+if (!(re_list_head = compile(*listptr)))
+  return FAIL;			/* no regexes -> nothing to do */
+
+/* check if the file is already decoded */
+if (!mime_decoded_filename)
+  {				/* no, decode it first */
+  const uschar *empty = US"";
+  mime_decode(&empty);
+  if (!mime_decoded_filename)
+    {				/* decoding failed */
+    log_write(0, LOG_MAIN,
+       "mime_regex acl condition warning - could not decode MIME part to file");
+    return DEFER;
+    }
+  }
+
+/* open file */
+if (!(f = fopen(CS mime_decoded_filename, "rb")))
+  {
+  log_write(0, LOG_MAIN,
+       "mime_regex acl condition warning - can't open '%s' for reading",
+       mime_decoded_filename);
+  return DEFER;
+  }
+
+/* get 32k memory, tainted */
+mime_subject = store_get(32767, GET_TAINTED);
+
+mime_subject_len = fread(mime_subject, 1, 32766, f);
+
+ret = matcher(re_list_head, mime_subject, mime_subject_len);
+(void)fclose(f);
+return ret;
+}
+
+#endif /* WITH_CONTENT_SCAN */