Fix segfault in wrapper error log mechanism when errors are logged on

second and subsequent events.
Implement very simple recursion protection for user streams written
like this:
class urlEncodeStream {
    var $fp = NULL;

    function stream_open($path, $mode, $options, &$opened_path)
    {
        $this->fp = fopen($path, $mode); // <-- this recurses infinitely
        return is_resource($this->fp);
    }
}

file_register_wrapper('urlencode', 'urlEncodeStream');
$fp = fopen('urlencode:///tmp/outputfile.txt', 'w');

Noticed by: Yasuo.

1 files changed, 10 insertions, 0 deletions

diff --git a/main/user_streams.c b/main/user_streams.c
index a6aff3cb8a..5c4ef63b92 100644
--- a/main/user_streams.c
+++ b/main/user_streams.c
@@ -21,6 +21,7 @@
 
 #include "php.h"
 #include "php_globals.h"
+#include "ext/standard/file.h"
 
 static int le_protocols;
 
@@ -137,6 +138,13 @@ static php_stream *user_wrapper_opener(php_stream_wrapper *wrapper, char *filena
 	int call_result;
 	php_stream *stream = NULL;
 
+	/* Try to catch bad usage without prevent flexibility */
+	if (FG(user_stream_current_filename) != NULL && strcmp(filename, FG(user_stream_current_filename)) == 0) {
+		php_stream_wrapper_log_error(wrapper, options TSRMLS_CC, "infinite recursion prevented");
+		return NULL;
+	}
+	FG(user_stream_current_filename) = filename;
+	
 	us = emalloc(sizeof(*us));
 	us->wrapper = uwrap;	
 
@@ -206,6 +214,8 @@ static php_stream *user_wrapper_opener(php_stream_wrapper *wrapper, char *filena
 	zval_ptr_dtor(&zmode);
 	zval_ptr_dtor(&zfilename);
 
+	FG(user_stream_current_filename) = NULL;
+		
 	return stream;
 }