From: Wez Furlong <wez@php.net>
Date: Thu, 26 Sep 2002 12:12:27 +0000 (+0000)
Subject: Fix segfault in wrapper error log mechanism when errors are logged on
X-Git-Tag: MODERN_SYMMETRIC_SESSION_BEHAVIOUR_20021003~160
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c484eb8c97b084b09e7368e0ac0947c0c4f4f46f;p=php

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.
---

diff --git a/ext/standard/file.c b/ext/standard/file.c
index b3d2fb539f..38497a4a71 100644
--- a/ext/standard/file.c
+++ b/ext/standard/file.c
@@ -132,6 +132,7 @@ static ZEND_RSRC_DTOR_FUNC(file_context_dtor)
 static void file_globals_ctor(php_file_globals *file_globals_p TSRMLS_DC)
 {
 	FG(pclose_ret) = 0;
+	FG(user_stream_current_filename) = NULL;
 	FG(def_chunk_size) = PHP_SOCK_CHUNK_SIZE;
 }
 
diff --git a/ext/standard/file.h b/ext/standard/file.h
index 3990504509..4e5eba55dd 100644
--- a/ext/standard/file.h
+++ b/ext/standard/file.h
@@ -115,6 +115,7 @@ typedef struct {
 	int auto_detect_line_endings;
 	int default_socket_timeout;
 	char *user_agent;
+	char *user_stream_current_filename; /* for simple recursion protection */
 } php_file_globals;
 
 #ifdef ZTS
diff --git a/main/streams.c b/main/streams.c
index fd22218901..ba8176dd63 100755
--- a/main/streams.c
+++ b/main/streams.c
@@ -1988,7 +1988,7 @@ PHPAPI php_stream *_php_stream_open_wrapper_ex(char *path, char *mode, int optio
 		int free_msg = 0;
 
 		if (wrapper) {
-			if (wrapper->err_count) {
+			if (wrapper->err_count > 0) {
 				int i;
 				size_t l;
 				int brlen;
@@ -2038,6 +2038,7 @@ PHPAPI php_stream *_php_stream_open_wrapper_ex(char *path, char *mode, int optio
 		if (wrapper->err_stack)
 			efree(wrapper->err_stack);
 		wrapper->err_stack = NULL;
+		wrapper->err_count = 0;
 	}
 #if ZEND_DEBUG
 	if (stream == NULL && copy_of_path != NULL)
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;
 }