Merge pull request #4887 from rspamd/vstakhov-regexp-fix

Protect regexp matcher from regexps with empty patterns

src/libserver/re_cache.c

 			if (max_hits > 0 && r >= max_hits) {
 				break;
 			}
+
+			if (start >= end) {
+				/* We found all matches, so no more hits are possible (protect from empty patterns) */
+				break;
+			}
 		}
 
 		rt->results[id] += r;

src/libutil/multipattern.c

 										&end,
 										TRUE,
 										NULL)) {
+				if (start >= end) {
+					/* We found all matches, so no more hits are possible (protect from empty patterns) */
+					break;
+				}
 				if (rspamd_multipattern_acism_cb(i, end - in, &cbd)) {
 					goto out;
 				}

src/libutil/regexp.c

 /*
- * Copyright 2023 Vsevolod Stakhov
+ * Copyright 2024 Vsevolod Stakhov
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
 	g_assert(text != NULL);
 
 	if (len == 0) {
-		len = strlen(text);
+		/* No length, no match! */
+		return FALSE;
 	}
 
 	if (re->match_limit > 0 && len > re->match_limit) {
 	g_assert(text != NULL);
 
 	if (len == 0) {
-		len = strlen(text);
+		/* No length, no match! */
+		return FALSE;
 	}
 
 	if (re->match_limit > 0 && len > re->match_limit) {
 	g_assert(re != NULL);
 	g_assert(text != NULL);
 
-	if (len == 0) {
-		len = strlen(text);
-	}
-
 	if (rspamd_regexp_search(re, text, len, &start, &end, raw, NULL)) {
 		if (start == text && end == text + len) {
 			return TRUE;
 
 	g_assert(gl != NULL);
 
-	if (sz == 0) {
-		sz = strlen(gl);
-	}
-
 	end = gl + sz;
 	out = g_string_sized_new(sz + 2);
 	g_string_append_c(out, '^');

src/lua/lua_regexp.c

 				}
 
 				matched = TRUE;
+
+				if (start >= end) {
+					/* We found all matches, so no more hits are possible (protect from empty patterns) */
+					break;
+				}
 			}
 
 			if (!matched) {
 					lua_rawseti(L, -2, ++i);
 					matched = TRUE;
 				}
-				else if (start == end) {
+				else if (start >= end) {
 					break;
 				}
 				old_start = end;

test/lua/unit/url.lua

       assert_equal(v[2], res, 'expected ' .. v[2] .. ' but got ' .. res .. ' in url ' .. v[1])
     end)
   end
+
+  test("URL regexp issue", function()
+    local rspamd_regexp = require "rspamd_regexp"
+    local u = url.create(pool,
+        'https://cls21.bullhornstaffing.com/MailerUnsubscribe.cfm?privateLabelID=3D26028&email=xpto&updKey=3D%3B%28U%2B%2F%200T%3EI%3B%2FQEI%5E%29%25XR%3FZ%40%5B%2EGJY%3CF%23%3F%25%22%29%5D%2D%0A')
+    assert_not_nil(u, "we are able to parse url")
+    local re = rspamd_regexp.create_cached("^$|^[?].*|^[#].*|[^#?]+")
+    assert_not_nil(re, "regexp is valid")
+    local res = re:search('/' .. u:get_path() .. '?' .. u:get_query())
+    assert_equal(res[#res], '')
+  end)
 end)