File gnash-CVE-2012-1175.diff of Package gnash
From bb4dc77eecb6ed1b967e3ecbce3dac6c5e6f1527 Mon Sep 17 00:00:00 2001
From: Benjamin Wolsey <bwy@benjaminwolsey.de>
Date: Sat, 10 Mar 2012 14:52:50 +0000
Subject: Fix crash in GnashImage.cpp
---
---
libbase/GnashImage.cpp | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
--- a/libbase/GnashImage.cpp
+++ b/libbase/GnashImage.cpp
@@ -24,6 +24,7 @@
#include <memory> // for auto_ptr
#include <boost/scoped_array.hpp>
#include <boost/shared_ptr.hpp>
+#include <cassert>
#include "FileTypes.h"
#include "GnashImage.h"
@@ -42,6 +43,21 @@ namespace gnash
namespace {
void processAlpha(GnashImage::iterator imageData, size_t pixels);
+ bool checkValidSize(size_t width, size_t height, size_t channels) {
+
+ if (width == 0 || height == 0) return false;
+
+ assert(channels > 0);
+
+ boost::uint32_t maxSize = std::numeric_limits<boost::int32_t>::max();
+ if (width >= maxSize || height >= maxSize) return false;
+
+ maxSize /= channels;
+ maxSize /= width;
+ maxSize /= height;
+
+ return maxSize > 0;
+ }
}
GnashImage::GnashImage(iterator data, size_t width, size_t height,
@@ -53,6 +69,8 @@ GnashImage::GnashImage(iterator data, si
_height(height),
_data(data)
{
+ // Callers should check dimensions
+ assert(checkValidSize(_width, _height, channels()));
}
/// Create an image allocating a buffer of height*pitch bytes
@@ -64,8 +82,9 @@ GnashImage::GnashImage(size_t width, siz
_width(width),
_height(height)
{
- const size_t max = std::numeric_limits<boost::int32_t>::max();
- if (size() > max) {
+ // Constructed from external input, so restrict dimensions to avoid
+ // overflow in size calculations
+ if (!checkValidSize(_width, _height, channels())) {
throw std::bad_alloc();
}
_data.reset(new value_type[size()]);