Fix #81122: SSRF bypass in FILTER_VALIDATE_URL

We need to ensure that the password detected by parse_url() is actually
a valid password; we can re-use is_userinfo_valid() for that.

ext/filter/logical_filters.c

@@ -628,7 +628,9 @@ void php_filter_validate_url(PHP_INPUT_FILTER_PARAM_DECL) /* {{{ */
 		RETURN_VALIDATION_FAILED
 	}
 
-	if (url->user != NULL && !is_userinfo_valid(url->user)) {
+	if (url->user != NULL && !is_userinfo_valid(url->user)
+		|| url->pass != NULL && !is_userinfo_valid(url->pass)
+	) {
 		php_url_free(url);
 		RETURN_VALIDATION_FAILED
 

ext/filter/tests/bug81122.phpt

@@ -0,0 +1,21 @@
+--TEST--
+Bug #81122 (SSRF bypass in FILTER_VALIDATE_URL)
+--SKIPIF--
+<?php
+if (!extension_loaded('filter')) die("skip filter extension not available");
+?>
+--FILE--
+<?php
+$urls = [
+    "https://example.com:\\@test.com/",
+    "https://user:\\epass@test.com",
+    "https://user:\\@test.com",
+];
+foreach ($urls as $url) {
+    var_dump(filter_var($url, FILTER_VALIDATE_URL));
+}
+?>
+--EXPECT--
+bool(false)
+bool(false)
+bool(false)