From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755383Ab0IOVuc (ORCPT ); Wed, 15 Sep 2010 17:50:32 -0400 Received: from mx1.vsecurity.com ([209.67.252.12]:52278 "EHLO mx1.vsecurity.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754434Ab0IOVua (ORCPT ); Wed, 15 Sep 2010 17:50:30 -0400 Subject: [PATCH] drivers/char/amiserial.c: prevent reading uninitialized stack memory From: Dan Rosenberg To: linux-kernel@vger.kernel.org Cc: security@kernel.org, stable@kernel.org Content-Type: text/plain; charset="UTF-8" Date: Wed, 15 Sep 2010 17:44:05 -0400 Message-ID: <1284587045.6275.98.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 TIOCGICOUNT device ioctl allows unprivileged users to read uninitialized stack memory, because the "reserved" member of the serial_icounter_struct 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/char/amiserial.c 2010-08-26 19:47:12.000000000 -0400 +++ linux-2.6.35.4/drivers/char/amiserial.c 2010-09-15 13:58:00.217343289 -0400 @@ -1342,6 +1342,9 @@ static int rs_ioctl(struct tty_struct *t local_irq_save(flags); cnow = info->state->icount; local_irq_restore(flags); + + memset(&icount, 0, sizeof(struct serial_icounter_struct)); + icount.cts = cnow.cts; icount.dsr = cnow.dsr; icount.rng = cnow.rng;