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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19BA7C4743C for ; Wed, 23 Jun 2021 14:37:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03EC66112D for ; Wed, 23 Jun 2021 14:37:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230476AbhFWOjX (ORCPT ); Wed, 23 Jun 2021 10:39:23 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:51340 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231310AbhFWOjR (ORCPT ); Wed, 23 Jun 2021 10:39:17 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lw3zq-00DaGO-Vs; Wed, 23 Jun 2021 08:36:58 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] 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 1lw3zp-00FFdy-0H; Wed, 23 Jun 2021 08:36:54 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Michael Schmitz Cc: Linus Torvalds , Al Viro , linux-arch , Jens Axboe , Oleg Nesterov , Linux Kernel Mailing List , Richard Henderson , Ivan Kokshaysky , Matt Turner , alpha , Geert Uytterhoeven , linux-m68k , Arnd Bergmann , Tejun Heo , Kees Cook , Tetsuo Handa , John Paul Adrian Glaubitz References: <924ec53c-2fd9-2e1c-bbb1-3fda49809be4@gmail.com> <87eed4v2dc.fsf@disp2133> <5929e116-fa61-b211-342a-c706dcb834ca@gmail.com> <87fsxjorgs.fsf@disp2133> <87h7hpbojt.fsf@disp2133> <20c787ec-4a3c-061c-c649-5bc3e7ef0464@gmail.com> <55bdad37-187b-e1f5-a359-c5206b20ff4d@gmail.com> Date: Wed, 23 Jun 2021 09:36:45 -0500 In-Reply-To: <55bdad37-187b-e1f5-a359-c5206b20ff4d@gmail.com> (Michael Schmitz's message of "Wed, 23 Jun 2021 17:26:22 +1200") Message-ID: <87sg18abr6.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=1lw3zp-00FFdy-0H;;;mid=<87sg18abr6.fsf@disp2133>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+NbP08c6rBMLpVRuWsiul7P0EciH0CoAk= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: Kernel stack read with PTRACE_EVENT_EXIT and io_uring threads 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 Michael Schmitz writes: > Hi Eric, > > Am 23.06.2021 um 09:48 schrieb Michael Schmitz: >>> >>> The challenging ones are /proc/pid/syscall and seccomp which want to see >>> all of the system call arguments. I think every architecture always >>> saves the system call arguments unconditionally, so those cases are >>> probably not as interesting. But they certain look like they could be >>> trouble. >> >> Seccomp hasn't yet been implemented on m68k, though I'm working on that >> with Adrian. The sole secure_computing() call will happen in >> syscall_trace_enter(), so all system call arguments have been saved on >> the stack. >> >> Haven't looked at /proc/pid/syscall yet ... > > Not supported at present (no HAVE_ARCH_TRACEHOOK for m68k). And the > syscall_get_arguments I wrote for seccomp support only copies the first five > data registers, which are always saved. Yes. It is looking like I can fix everything generically except for faking user space registers for io_uring threads. Eric