Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752354AbZD2NZq (ORCPT ); Wed, 29 Apr 2009 09:25:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755473AbZD2NZJ (ORCPT ); Wed, 29 Apr 2009 09:25:09 -0400 Received: from msux-gh1-uea01.nsa.gov ([63.239.67.1]:64101 "EHLO msux-gh1-uea01.nsa.gov" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758853AbZD2NZI (ORCPT ); Wed, 29 Apr 2009 09:25:08 -0400 Subject: Re: Q: selinux_bprm_committed_creds() && signals/do_wait From: Stephen Smalley To: Oleg Nesterov Cc: David Howells , Eric Paris , James Morris , Roland McGrath , linux-kernel@vger.kernel.org In-Reply-To: <20090428223025.GA11997@redhat.com> References: <20090428223025.GA11997@redhat.com> Content-Type: text/plain Organization: National Security Agency Date: Wed, 29 Apr 2009 09:18:36 -0400 Message-Id: <1241011116.18249.193.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.24.5 (2.24.5-1.fc10) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1375 Lines: 41 On Wed, 2009-04-29 at 00:30 +0200, Oleg Nesterov wrote: > selinux_bprm_committed_creds: > > rc = avc_has_perm() > if (rc) { > flush_signals(current); > > This doesn't look right. If the task was SIGKILL'ed we must not proceed, > the task should die. The fix is simple, we should check SIGNAL_GROUP_EXIT > and do nothing in this case, the task will exit before return to user > space. If SIGNAL_GROUP_EXIT is set, it is just wrong to drop SIGKILL and > continue. > > But, before fixing, I'd like to understand why we are doing > > flush_signal_handlers(current, 1); > sigemptyset(¤t->blocked); > > later. Could someone explain ? This looks unneeded. > > > Another question, > > wake_up_interruptible(¤t->parent->signal->wait_chldexit); > > Shouldn't we use ->real_parent ? Afaics, we shouldn't worry about the tracer > if current is ptraced, exec must not succeed if the tracer has no rights to > trace this task after cred changing. But we should notify ->real_parent which > is, well, real parent. That makes sense to me - yes, s/parent/real_parent/. -- Stephen Smalley National Security Agency -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/