From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755447Ab0IOVu6 (ORCPT ); Wed, 15 Sep 2010 17:50:58 -0400 Received: from mx1.vsecurity.com ([209.67.252.12]:52438 "EHLO mx1.vsecurity.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755436Ab0IOVu4 (ORCPT ); Wed, 15 Sep 2010 17:50:56 -0400 Subject: [PATCH] drivers/media/video/ivtv/ivtvfb.c: prevent reading uninitialized stack memory From: Dan Rosenberg To: awalls@md.metrocast.net Cc: ivtv-devel@ivtvdriver.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, security@kernel.org, stable@kernel.org Content-Type: text/plain; charset="UTF-8" Date: Wed, 15 Sep 2010 17:44:22 -0400 Message-ID: <1284587062.6275.102.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/media/video/ivtv/ivtvfb.c 2010-08-26 19:47:12.000000000 -0400 +++ linux-2.6.35.4/drivers/media/video/ivtv/ivtvfb.c 2010-09-15 14:16:46.797375399 -0400 @@ -458,6 +458,8 @@ static int ivtvfb_ioctl(struct fb_info * struct fb_vblank vblank; u32 trace; + memset(&vblank, 0, sizeof(struct fb_vblank)); + vblank.flags = FB_VBLANK_HAVE_COUNT |FB_VBLANK_HAVE_VCOUNT | FB_VBLANK_HAVE_VSYNC; trace = read_reg(IVTV_REG_DEC_LINE_FIELD) >> 16;