From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755328Ab0IOVvd (ORCPT ); Wed, 15 Sep 2010 17:51:33 -0400 Received: from mx1.vsecurity.com ([209.67.252.12]:49615 "EHLO mx1.vsecurity.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751727Ab0IOVvb (ORCPT ); Wed, 15 Sep 2010 17:51:31 -0400 Subject: [PATCH] drivers/video/via/ioctl.c: prevent reading uninitialized stack memory From: Dan Rosenberg To: JosephChan@via.com.tw, ScottFang@viatech.com.cn Cc: linux-fbdev@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 17:44:19 -0400 Message-ID: <1284587059.6275.101.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 VIAFB_GET_INFO device ioctl allows unprivileged users to read 1968 bytes of uninitialized stack memory, because the "reserved" member of the viafb_ioctl_info 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/via/ioctl.c 2010-08-26 19:47:12.000000000 -0400 +++ linux-2.6.35.4/drivers/video/via/ioctl.c 2010-09-15 11:53:29.997375748 -0400 @@ -25,6 +25,8 @@ int viafb_ioctl_get_viafb_info(u_long ar { struct viafb_ioctl_info viainfo; + memset(&viainfo, 0, sizeof(struct viafb_ioctl)); + viainfo.viafb_id = VIAID; viainfo.vendor_id = PCI_VIA_VENDOR_ID;