From 37dd6285cdfc2129a49f26d09addb27cb017ae61 Mon Sep 17 00:00:00 2001 From: Alan Coopersmith Date: Wed, 22 Jan 2014 21:11:16 -0800 Subject: [PATCH 02/31] dix: integer overflow in ProcPutImage() [CVE-2014-8092 1/4] ProcPutImage() calculates a length field from a width, left pad and depth specified by the client (if the specified format is XYPixmap). The calculations for the total amount of memory the server needs for the pixmap can overflow a 32-bit number, causing out-of-bounds memory writes on 32-bit systems (since the length is stored in a long int variable). Reported-by: Ilja Van Sprundel Signed-off-by: Alan Coopersmith Reviewed-by: Peter Hutterer Signed-off-by: Fedora X Ninjas --- dix/dispatch.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/dix/dispatch.c b/dix/dispatch.c index 979ba48..8cb23d1 100644 --- a/dix/dispatch.c +++ b/dix/dispatch.c @@ -1955,6 +1955,9 @@ ProcPutImage(ClientPtr client) tmpImage = (char *) &stuff[1]; lengthProto = length; + if (lengthProto >= (INT32_MAX / stuff->height)) + return BadLength; + if ((bytes_to_int32(lengthProto * stuff->height) + bytes_to_int32(sizeof(xPutImageReq))) != client->req_len) return BadLength; -- 1.9.3