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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB8D5C433F5 for ; Thu, 21 Oct 2021 17:03:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A96AB61037 for ; Thu, 21 Oct 2021 17:03:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232127AbhJURFS (ORCPT ); Thu, 21 Oct 2021 13:05:18 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:40282 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231440AbhJURFP (ORCPT ); Thu, 21 Oct 2021 13:05:15 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]:59376) by out03.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1mdbT0-005fTo-ML; Thu, 21 Oct 2021 11:02:58 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95]:57008 helo=email.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 1mdbSy-00CpzD-L6; Thu, 21 Oct 2021 11:02:58 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Kees Cook Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Linus Torvalds , Oleg Nesterov , Al Viro , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, H Peter Anvin References: <87y26nmwkb.fsf@disp2133> <20211020174406.17889-10-ebiederm@xmission.com> <202110210915.BF17C14980@keescook> Date: Thu, 21 Oct 2021 12:02:49 -0500 In-Reply-To: <202110210915.BF17C14980@keescook> (Kees Cook's message of "Thu, 21 Oct 2021 09:16:02 -0700") Message-ID: <87r1ce8g5i.fsf@disp2133> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1mdbSy-00CpzD-L6;;;mid=<87r1ce8g5i.fsf@disp2133>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+4tFpR82thOj+XqsfADzJzogO4+LK+nWA= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH 10/20] signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved. 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-kernel@vger.kernel.org Kees Cook writes: > On Wed, Oct 20, 2021 at 12:43:56PM -0500, Eric W. Biederman wrote: >> Instead of pretending to send SIGSEGV by calling do_exit(SIGSEGV) >> call force_sigsegv(SIGSEGV) to force the process to take a SIGSEGV >> and terminate. >> >> Update handle_signal to return immediately when save_v86_state fails >> and kills the process. Returning immediately without doing anything >> except killing the process with SIGSEGV is also what signal_setup_done >> does when setup_rt_frame fails. Plus it is always ok to return >> immediately without delivering a signal to a userspace handler when a >> fatal signal has killed the current process. > > Do the tools/testing/selftests/x86 tests all pass after these changes? I > know Andy has a bunch of weird corner cases in there. That would require a 32bit userspace wouldn't it? It is a good idea so I will see if I can dig such a box up, but I unfortunately don't have an up-to-date 32bit box handy, or even an up-to-date box with a 32bit userspace. It has been about 20 years since I have done much with 32bit x86. How hard is it to run the tests under tools/testing/selftests/... Last time I tried it was a royal pain. I am hoping it is better this round. Eric