From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Date: Mon, 18 Oct 2010 15:10:20 +0000 Subject: Re: [PATCH 2/8] char: hpet: fix information leak to userland Message-Id: <4CBC635C.6030500@ladisch.de> List-Id: References: <1287326477-7940-1-git-send-email-segooon@gmail.com> In-Reply-To: <1287326477-7940-1-git-send-email-segooon@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Vasiliy Kulikov Cc: kernel-janitors@vger.kernel.org, "Eric W. Biederman" , Arnd Bergmann , Andrew Morton , Frederic Weisbecker , Tejun Heo , linux-kernel@vger.kernel.org Vasiliy Kulikov wrote: > Structure info is copied to userland with some padding fields unitialized. > It leads to leaking of stack memory. > --- a/drivers/char/hpet.c > +++ b/drivers/char/hpet.c > @@ -581,6 +581,7 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, > break; > case HPET_INFO: > { > + memset(info, 0, sizeof(*info)); > if (devp->hd_ireqfreq) > info->hi_ireqfreq > hpet_time_div(hpetp, devp->hd_ireqfreq); This makes the following assignment "info->hi_ireqfreq = 0;" superfluous. Regards, Clemens From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756640Ab0JRPJJ (ORCPT ); Mon, 18 Oct 2010 11:09:09 -0400 Received: from out1.smtp.messagingengine.com ([66.111.4.25]:39479 "EHLO out1.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753388Ab0JRPJI (ORCPT ); Mon, 18 Oct 2010 11:09:08 -0400 X-Sasl-enc: NOD9efgN1ewFJvW2XJgDaxgIaPZnf0K+vJcczmw7keDZ 1287414546 Message-ID: <4CBC635C.6030500@ladisch.de> Date: Mon, 18 Oct 2010 17:10:20 +0200 From: Clemens Ladisch User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Vasiliy Kulikov CC: kernel-janitors@vger.kernel.org, "Eric W. Biederman" , Arnd Bergmann , Andrew Morton , Frederic Weisbecker , Tejun Heo , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/8] char: hpet: fix information leak to userland References: <1287326477-7940-1-git-send-email-segooon@gmail.com> In-Reply-To: <1287326477-7940-1-git-send-email-segooon@gmail.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Vasiliy Kulikov wrote: > Structure info is copied to userland with some padding fields unitialized. > It leads to leaking of stack memory. > --- a/drivers/char/hpet.c > +++ b/drivers/char/hpet.c > @@ -581,6 +581,7 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, > break; > case HPET_INFO: > { > + memset(info, 0, sizeof(*info)); > if (devp->hd_ireqfreq) > info->hi_ireqfreq = > hpet_time_div(hpetp, devp->hd_ireqfreq); This makes the following assignment "info->hi_ireqfreq = 0;" superfluous. Regards, Clemens