From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759712Ab2IEWGN (ORCPT ); Wed, 5 Sep 2012 18:06:13 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40385 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759674Ab2IEWGL (ORCPT ); Wed, 5 Sep 2012 18:06:11 -0400 Message-ID: <5047CCCB.1000108@canonical.com> Date: Wed, 05 Sep 2012 15:06:03 -0700 From: John Johansen Organization: Canonical User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120827 Thunderbird/15.0 MIME-Version: 1.0 To: Kees Cook CC: linux-kernel@vger.kernel.org, James Morris , Dan Carpenter , linux-security-module@vger.kernel.org Subject: Re: [PATCH] Yama: handle 32-bit userspace prctl References: <20120827183813.GA23991@www.outflux.net> In-Reply-To: <20120827183813.GA23991@www.outflux.net> X-Enigmail-Version: 1.4.4 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/27/2012 11:38 AM, Kees Cook wrote: > When running a 64-bit kernel and receiving prctls from a 32-bit > userspace, the "-1" used as an unsigned long will end up being > misdetected. The kernel is looking for 0xffffffffffffffff instead of > 0xffffffff. Since prctl lacks a distinct compat interface, Yama needs > to handle this translation itself. As such, support either value as > meaning PR_SET_PTRACER_ANY, to avoid breaking the ABI for 64-bit. > > Signed-off-by: Kees Cook > Cc: stable@vger.kernel.org > --- > security/yama/yama_lsm.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c > index 0cc99a3..dcd6178 100644 > --- a/security/yama/yama_lsm.c > +++ b/security/yama/yama_lsm.c > @@ -143,7 +143,7 @@ static int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3, > if (arg2 == 0) { > yama_ptracer_del(NULL, myself); > rc = 0; > - } else if (arg2 == PR_SET_PTRACER_ANY) { > + } else if (arg2 == PR_SET_PTRACER_ANY || (int)arg2 == -1) { > rc = yama_ptracer_add(NULL, myself); > } else { > struct task_struct *tracer; > yeah this looks good it should at least hit stable Acked-by: John Johansen