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
---
diff --git a/libbase/GnashImage.cpp b/libbase/GnashImage.cpp
index 11c6956..03a6939 100644
--- a/libbase/GnashImage.cpp
+++ b/libbase/GnashImage.cpp
@@ -26,6 +26,7 @@
#include <boost/scoped_array.hpp>
#include <boost/shared_ptr.hpp>
#include <algorithm>
+#include <cassert>
#ifdef USE_PNG
# include "GnashImagePng.h"
@@ -44,6 +45,21 @@ namespace image {
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,
@@ -55,6 +71,8 @@ GnashImage::GnashImage(iterator data, size_t width, size_t height,
_height(height),
_data(data)
{
+ // Callers should check dimensions
+ assert(checkValidSize(_width, _height, channels()));
}
/// Create an image allocating a buffer of height*pitch bytes
@@ -66,8 +84,9 @@ GnashImage::GnashImage(size_t width, size_t height, ImageType type,
_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()]);
--
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