From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11A46C433F5 for ; Thu, 10 Feb 2022 18:18:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245631AbiBJSR7 (ORCPT ); Thu, 10 Feb 2022 13:17:59 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:44428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245650AbiBJSR6 (ORCPT ); Thu, 10 Feb 2022 13:17:58 -0500 Received: from out03.mta.xmission.com (out03.mta.xmission.com [166.70.13.233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B244EC4B; Thu, 10 Feb 2022 10:17:59 -0800 (PST) Received: from in01.mta.xmission.com ([166.70.13.51]:41096) by out03.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nIE10-00AGdg-LX; Thu, 10 Feb 2022 11:17:58 -0700 Received: from ip68-227-174-4.om.om.cox.net ([68.227.174.4]:41388 helo=email.froward.int.ebiederm.org.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nIE0z-00Dbz8-QO; Thu, 10 Feb 2022 11:17:58 -0700 From: "Eric W. Biederman" To: Kees Cook Cc: Robert =?utf-8?B?xZp3acSZY2tp?= , Andy Lutomirski , Will Drewry , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20220210025321.787113-1-keescook@chromium.org> Date: Thu, 10 Feb 2022 12:17:50 -0600 In-Reply-To: <20220210025321.787113-1-keescook@chromium.org> (Kees Cook's message of "Wed, 9 Feb 2022 18:53:18 -0800") Message-ID: <871r0a8u29.fsf@email.froward.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1nIE0z-00Dbz8-QO;;;mid=<871r0a8u29.fsf@email.froward.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.174.4;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/0ElVN4jF3VxNbNbK8Cp+alPjWl5IMXlo= X-SA-Exim-Connect-IP: 68.227.174.4 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH 0/3] signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Kees Cook writes: > Hi, > > This fixes the signal refactoring to actually kill unkillable processes > when receiving a fatal SIGSYS from seccomp. Thanks to Robert for the > report and Eric for the fix! I've also tweaked seccomp internal a bit to > fail more safely. This was a partial seccomp bypass, in the sense that > SECCOMP_RET_KILL_* didn't kill the process, but it didn't bypass other > aspects of the filters. (i.e. the syscall was still blocked, etc.) Any luck on figuring out how to suppress the extra event? > > I'll be sending this to Linus after a bit more testing... > > Thanks, > > -Kees > > Kees Cook (3): > signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE > seccomp: Invalidate seccomp mode to catch death failures > samples/seccomp: Adjust sample to also provide kill option > > kernel/seccomp.c | 10 ++++++++++ > kernel/signal.c | 5 +++-- > samples/seccomp/dropper.c | 9 +++++++-- > 3 files changed, 20 insertions(+), 4 deletions(-) Eric