From cb6a5f76681cbd575a997450a9f33e729f459b05 Mon Sep 17 00:00:00 2001
From: ludwig <ludwig@edf5b092-35ff-0310-97b2-ce42778d08ea>
Date: Tue, 12 Feb 2008 10:03:43 +0000
Subject: integer overflow safeguards

git-svn-id: svn://svn.icculus.org/quake3/trunk@1254 edf5b092-35ff-0310-97b2-ce42778d08ea
---
 code/renderer/tr_image_png.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/code/renderer/tr_image_png.c b/code/renderer/tr_image_png.c
index 30a8951..573ab12 100644
--- a/code/renderer/tr_image_png.c
+++ b/code/renderer/tr_image_png.c
@@ -23,6 +23,11 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 #include "../qcommon/puff.h"
 
+// we could limit the png size to a lower value here
+#ifndef INT_MAX
+#define INT_MAX 0x1fffffff
+#endif
+
 /*
 =================
 PNG LOADING
@@ -287,7 +292,7 @@ static void CloseBufferedFile(struct BufferedFile *BF)
  *  Get a pointer to the requested bytes.
  */
 
-static void *BufferedFileRead(struct BufferedFile *BF, int Length)
+static void *BufferedFileRead(struct BufferedFile *BF, unsigned Length)
 {
 	void *RetVal;
 
@@ -329,9 +334,9 @@ static void *BufferedFileRead(struct BufferedFile *BF, int Length)
  *  Rewind the buffer.
  */
 
-static qboolean BufferedFileRewind(struct BufferedFile *BF, int Offset)
+static qboolean BufferedFileRewind(struct BufferedFile *BF, unsigned Offset)
 {
-	int BytesRead; 
+	unsigned BytesRead; 
 
 	/*
 	 *  input verification
@@ -346,7 +351,7 @@ static qboolean BufferedFileRewind(struct BufferedFile *BF, int Offset)
 	 *  special trick to rewind to the beginning of the buffer
 	 */
 
-	if(Offset == -1)
+	if(Offset == (unsigned)-1)
 	{
 		BF->Ptr       = BF->Buffer;
 		BF->BytesLeft = BF->Length;
@@ -383,7 +388,7 @@ static qboolean BufferedFileRewind(struct BufferedFile *BF, int Offset)
  *  Skip some bytes.
  */
 
-static qboolean BufferedFileSkip(struct BufferedFile *BF, int Offset)
+static qboolean BufferedFileSkip(struct BufferedFile *BF, unsigned Offset)
 {
 	/*
 	 *  input verification
@@ -2041,10 +2046,13 @@ void LoadPNG(const char *name, byte **pic, int *width, int *height)
 	 *  Check if Width and Height are valid.
 	 */
 
-	if(!((IHDR_Width > 0) && (IHDR_Height > 0)))
+	if(!((IHDR_Width > 0) && (IHDR_Height > 0))
+	|| IHDR_Width > INT_MAX / Q3IMAGE_BYTESPERPIXEL / IHDR_Height)
 	{
 		CloseBufferedFile(ThePNG);
 
+		Com_Printf(S_COLOR_YELLOW "%s: invalid image size\n", name);
+
 		return; 
 	}
 
-- 
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