Throw ValueError instead of generic exception

Remove old counting code

Author: Sjoerd Langkemper

ext/standard/php_fopen_wrapper.c

@@ -145,27 +145,20 @@ static const php_stream_ops php_stream_input_ops = {
 	NULL  /* set_option */
 };
 
-static const char max_stream_filters = 5;
+static const char max_stream_filters = 16;
 
 static void php_stream_apply_filter_list(php_stream *stream, char *filterlist, int read_chain, int write_chain) /* {{{ */
 {
 	char *p, *token = NULL;
 	php_stream_filter *temp_filter;
-	char nb_filters = 0;
 
 	p = php_strtok_r(filterlist, "|", &token);
 	while (p) {
-		if (nb_filters >= max_stream_filters) {
-			zend_throw_exception_ex(NULL, 0, "Unable to apply filter, maximum number (%d) reached", max_stream_filters);
-			return;
-		}
-		nb_filters++;
-
 		php_url_decode(p, strlen(p));
 		if (read_chain) {
 			if ((temp_filter = php_stream_filter_create(p, NULL, php_stream_is_persistent(stream)))) {
-				if (php_stream_filter_count(&stream->readfilters) > max_stream_filters) {
-					zend_throw_exception_ex(NULL, 0, "Unable to apply read filter, maximum number (%d) reached", max_stream_filters);
+				if (php_stream_filter_count(&stream->readfilters) >= max_stream_filters) {
+					zend_value_error("Unable to apply read filter, maximum number (%d) reached", max_stream_filters);
 					return;
 				}
 				php_stream_filter_append(&stream->readfilters, temp_filter);
@@ -175,8 +168,8 @@ static void php_stream_apply_filter_list(php_stream *stream, char *filterlist, i
 		}
 		if (write_chain) {
 			if ((temp_filter = php_stream_filter_create(p, NULL, php_stream_is_persistent(stream)))) {
-				if (php_stream_filter_count(&stream->writefilters) > max_stream_filters) {
-					zend_throw_exception_ex(NULL, 0, "Unable to apply write filter, maximum number (%d) reached", max_stream_filters);
+				if (php_stream_filter_count(&stream->writefilters) >= max_stream_filters) {
+					zend_value_error("Unable to apply write filter, maximum number (%d) reached", max_stream_filters);
 					return;
 				}
 				php_stream_filter_append(&stream->writefilters, temp_filter);

ext/standard/tests/filters/max_filter_chain.phpt

@@ -0,0 +1,38 @@
+--TEST--
+At most 16 filters can be chained in one stream
+--EXTENSIONS--
+filter
+--FILE--
+<?php
+
+function createFilterChains($n) {
+    $filter = 'string.toupper';
+    $resource = 'data:text/plain,hello';
+    $pipes = 'php://filter/' . implode('|', array_fill(0, $n, $filter)) . "/resource=$resource";
+    $slashes = 'php://filter/' . implode('/', array_fill(0, $n, $filter)) . "/resource=$resource";
+    $resources = str_repeat("php://filter/$filter/resource=", $n) . $resource;
+    return [$pipes, $slashes, $resources];
+}
+
+$allowed_chains = createFilterChains(16);
+foreach ($allowed_chains as $chain) {
+    var_dump(file_get_contents($chain));
+}
+
+$blocked_chains = createFilterChains(17);
+foreach ($blocked_chains as $chain) {
+    try {
+        var_dump(file_get_contents($chain));
+    } catch (ValueError $e) {
+        echo "ValueError\n";
+    }
+}
+
+?>
+--EXPECT--
+string(5) "HELLO"
+string(5) "HELLO"
+string(5) "HELLO"
+ValueError
+ValueError
+ValueError