Add key prefix check for userspace wrappers

Author: flaupretre

…/streams/streams_cache_key_user_001.phpt …s/streams/stream_cache_key_user_001.phptext/standard/tests/streams/streams_cache_key_user_001.phpt renamed to ext/standard/tests/streams/stream_cache_key_user_001.phpt ext/standard/tests/streams/streams_cache_key_user_001.phpt renamed to ext/standard/tests/streams/stream_cache_key_user_001.phpt

@@ -1,12 +1,13 @@
 --TEST--
-Empty cache key returned from userspace wrapper
+Invalid key returned by userspace cache_key() method
 --FILE--
 <?php
 class MyWrapper
 {
+
 public function stream_cache_key($uri)
 {
-return '';
+return 'invalid_key';
 }
 
 }
@@ -19,4 +20,5 @@ var_dump(file_cache_key('mystream://random/path'));
 
 ?>
 --EXPECTF--
-NULL
+Fatal error: file_cache_key(): cache_key: Key (invalid_key) should start with same prefix as URL (mystream://random/path) in %s on line %d
+

…/streams/streams_cache_key_user_002.phpt …s/streams/stream_cache_key_user_002.phptext/standard/tests/streams/streams_cache_key_user_002.phpt renamed to ext/standard/tests/streams/stream_cache_key_user_002.phpt ext/standard/tests/streams/streams_cache_key_user_002.phpt renamed to ext/standard/tests/streams/stream_cache_key_user_002.phpt

@@ -1410,6 +1410,8 @@ static zend_string *user_wrapper_cache_key(php_stream_wrapper *wrapper, zend_str
 	int call_result;
 	zval object;
 	zend_string *ret;
+	const char *p1;
+	size_t prefix_len;
 
 	/* create an instance of our class */
 	user_stream_create_object(uwrap, context, &object);
@@ -1438,6 +1440,20 @@ static zend_string *user_wrapper_cache_key(php_stream_wrapper *wrapper, zend_str
 			ZVAL_DEREF(zp);
 			convert_to_string(zp); /* Convert returned key to string */
 			ret = Z_STR_P(zp);
+			
+			/* Check that url and key have the same '<scheme>://' prefix */
+			if (url != ret) {
+				p1=php_memnstr(ZSTR_VAL(url), "://", sizeof("://") - 1
+					, ZSTR_VAL(url) + ZSTR_LEN(url));
+				ZEND_ASSERT(p1); /* url must contain '://' */
+				prefix_len=p1-ZSTR_VAL(url)+3; /* Prefix length */
+				if ((prefix_len > ZSTR_LEN(ret)) || strncmp(ZSTR_VAL(ret), ZSTR_VAL(url), prefix_len)) {
+					php_error_docref(NULL, E_ERROR, "cache_key: Key (%s) should start with same prefix as URL (%s)",
+						ZSTR_VAL(ret), ZSTR_VAL(url));
+					zend_string_release(ret);
+					ret = NULL; /* Discard key */
+				}
+			}
 		}
 	} else {
 		/* No error if method is not implemented. URL is just not cacheable. */