From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755368Ab0IOVuT (ORCPT ); Wed, 15 Sep 2010 17:50:19 -0400 Received: from mx1.vsecurity.com ([209.67.252.12]:64967 "EHLO mx1.vsecurity.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755350Ab0IOVuQ (ORCPT ); Wed, 15 Sep 2010 17:50:16 -0400 Subject: [PATCH] drivers/video/sis/sis_main.c: prevent reading uninitialized stack memory From: Dan Rosenberg To: thomas@winischhofer.net Cc: linux-kernel@vger.kernel.org, security@kernel.org, stable@kernel.org Content-Type: text/plain; charset="UTF-8" Date: Wed, 15 Sep 2010 17:43:53 -0400 Message-ID: <1284587033.6275.96.camel@dan> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The FBIOGET_VBLANK device ioctl allows unprivileged users to read 16 bytes of uninitialized stack memory, because the "reserved" member of the fb_vblank struct declared on the stack is not altered or zeroed before being copied back to the user. This patch takes care of it. Signed-off-by: Dan Rosenberg --- linux-2.6.35.4.orig/drivers/video/sis/sis_main.c 2010-08-26 19:47:12.000000000 -0400 +++ linux-2.6.35.4/drivers/video/sis/sis_main.c 2010-09-15 11:52:41.437375730 -0400 @@ -1701,6 +1701,9 @@ static int sisfb_ioctl(struct fb_info *i break; case FBIOGET_VBLANK: + + memset(&sisvbblank, 0, sizeof(struct fb_vblank)); + sisvbblank.count = 0; sisvbblank.flags = sisfb_setupvbblankflags(ivideo, &sisvbblank.vcount, &sisvbblank.hcount);