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 B344EC433EF for ; Fri, 18 Mar 2022 17:20:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239559AbiCRRWI (ORCPT ); Fri, 18 Mar 2022 13:22:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235952AbiCRRWH (ORCPT ); Fri, 18 Mar 2022 13:22:07 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A42A2DF3FF for ; Fri, 18 Mar 2022 10:20:48 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id n7-20020a17090aab8700b001c6aa871860so2768895pjq.2 for ; Fri, 18 Mar 2022 10:20:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wI8RFHnMZ/ord/RFlr63IZcZowLUZNUmIF9gHirMLqk=; b=krmhetMSHSN+BhgLY4DNV1HbVv0fwryryHNFyHRc3Zd2xEn0QEi7bS97QQNjCp4VST KQX96x29cdCNw3OHSvE8aOkTlm7mOmlud6/5pjV8KdXSS7qfYehWUvKWHLr+1gQ9w1t7 PhH1Eb1gRgVgvgeDHo0dIZesx8U1zBVS1YEcs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wI8RFHnMZ/ord/RFlr63IZcZowLUZNUmIF9gHirMLqk=; b=ZFJ8phkgnf81tHaV4/rul+yD0miaQh4wukP0Cu0IHx/90Mr0oiYFpTEmuAVqvSgZlz xA4sNYZD1HAltJAjRzCCQVrpQeMSlPzZmZRd+EblT+sSudbUDLLpphlRHKijhj3NVmUJ aXxRjdQRLtbrG7rHXvIm4fVoTCTYWzcgFGkb37TTD2rHAogHoa+g7MVOqkU758aeGmAU geO+fx1aFGor3YS2Hx4Tz0DFdF1aEjgfIgJOV7ZGxOoEfLxEZHlc6UFCAh/mrcnPdRpC qnpZF5ZCHU4JPRtyFp5vmti8ZcCyEo6Z9qgMoJeo3I998zMrTYeMJtubhp9xAa1nQzGJ r1+Q== X-Gm-Message-State: AOAM531UWXd4FRkdjRcgF7DKm2fNYChXwkHI/qff10ZAQHp96jmUv7PC H+h2+uMqlj1QQ3AeHMENmoAXlw== X-Google-Smtp-Source: ABdhPJzSQb+APMshfGD9QDYJDR1zXQnnjMDlvX76HFd4hafq269zaDls7rytBGplARDSLpfnGdNJFg== X-Received: by 2002:a17:90a:e397:b0:1c6:3b63:bcbe with SMTP id b23-20020a17090ae39700b001c63b63bcbemr12105144pjz.180.1647624047726; Fri, 18 Mar 2022 10:20:47 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id q3-20020a63ae03000000b003820cc3a451sm4220567pgf.45.2022.03.18.10.20.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Mar 2022 10:20:47 -0700 (PDT) Date: Fri, 18 Mar 2022 10:20:46 -0700 From: Kees Cook To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Alexey Gladkov , Kyle Huey , Oleg Nesterov , Al Viro , linux-api@vger.kernel.org, Jens Axboe Subject: Re: [PATCH 1/2] ptrace: Move setting/clearing ptrace_message into ptrace_stop Message-ID: <202203181019.434DA4186@keescook> References: <87a6ha4zsd.fsf@email.froward.int.ebiederm.org> <87bl1kunjj.fsf@email.froward.int.ebiederm.org> <87r19opkx1.fsf_-_@email.froward.int.ebiederm.org> <87o82gdlu9.fsf_-_@email.froward.int.ebiederm.org> <87tubyx0rg.fsf_-_@email.froward.int.ebiederm.org> <87bky67qfv.fsf_-_@email.froward.int.ebiederm.org> <202203171209.FC87C7B08@keescook> <87fsnf2ucx.fsf@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87fsnf2ucx.fsf@email.froward.int.ebiederm.org> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Fri, Mar 18, 2022 at 09:44:30AM -0500, Eric W. Biederman wrote: > Kees Cook writes: > > > On Tue, Mar 15, 2022 at 06:21:08PM -0500, Eric W. Biederman wrote: > >> > >> Today ptrace_message is easy to overlook as it not a core part of > >> ptrace_stop. It has been overlooked so much that there are places > >> that set ptrace_message and don't clear it, and places that never set > >> it. So if you get an unlucky sequence of events the ptracer may be > >> able to read a ptrace_message that does not apply to the current > >> ptrace stop. > >> > >> Move setting of ptrace_message into ptrace_stop so that it always gets > >> set before the stop, and always gets cleared after the stop. This > >> prevents non-sense from being reported to userspace and makes > >> ptrace_message more visible in the ptrace helper functions so that > >> kernel developers can see it. > >> > >> Signed-off-by: "Eric W. Biederman" > > > > This looks good to me. Did you happen to run the seccomp selftests > > before/after these changes? > > I did not. This is a pure ptrace change. Do you see a way that seccomp > could be involved? Sorry, that wasn't clear: seccomp includes a number of ptrace tests as well, especially involving handling process death, messages, and signals. I'll give it a spin; so far it seems fine. -- Kees Cook