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 424A8C43217 for ; Fri, 14 Oct 2022 03:54:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229666AbiJNDy0 (ORCPT ); Thu, 13 Oct 2022 23:54:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229861AbiJNDyT (ORCPT ); Thu, 13 Oct 2022 23:54:19 -0400 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA06619E920 for ; Thu, 13 Oct 2022 20:54:16 -0700 (PDT) Received: by mail-pf1-x42a.google.com with SMTP id f140so3791542pfa.1 for ; Thu, 13 Oct 2022 20:54:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=BQMeWu4NUS5XHxpYjKe5lPkeUdCMvZeCueelrFJNv7g=; b=hVsj8yBrgKuKkK7M8xkb+HyKOAR1jqjYGdTOSBbuFw1xtWaGZRldfWed4W2s4PX8vj gMHC+/MyceBR4MHXpZkl8R1pYEcZzKSZwB0eAGg1tk/SYjiAH2KDJtEmiRns8TV0xEj3 Z26bm3qSWSWPK1j2fJ6oI+/9oCd9hoET+A3WM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=BQMeWu4NUS5XHxpYjKe5lPkeUdCMvZeCueelrFJNv7g=; b=fNLSVIYyHqj/PzYRTI1yQQjkUT33SQBiAxGairnUqQzWFtroAmgX6KC8K/xDzvDCMp oRvhHZ6dqVbN3VH5sq7ypzX4UEpgpKtfD/4j2yEGIm/JZAFB1bxmtdMUqVG5Ll+B/SyM iW0C+DRBUk7tSgBy0ASnULphbwoI57qWgO29Z7MjCvM42FLi7XM8279OpHBjSF3Q9tuU DoR5a7oCeIFvWyTAAdyOfQ2xQqBNXP+uQx51CxnJSaB6AwsFQ640F2rGUrLgN+qcxJ29 eH8BenpxoV6czgF+4WUkeOIwWGRvMv11982HbDO6fqLHUz4vHOVYUySUJ6RjJ5VW9AIE ChXg== X-Gm-Message-State: ACrzQf2EuYpegUUHPpylRlsyIs+Xk31sgjJIb3JtrNix1pXkRMZfwQmp gJ+ui2uu6qSVHLmA7i9zfPuLDA== X-Google-Smtp-Source: AMsMyM7vCfA8wFrsyDJjLw6KB1kvioIeLEFXGEDdVpYcSJdvjz4XjS2+1dICHf/21nwZwt5L/DrvHw== X-Received: by 2002:a63:591c:0:b0:464:bb3b:d1ad with SMTP id n28-20020a63591c000000b00464bb3bd1admr2830780pgb.146.1665719656162; Thu, 13 Oct 2022 20:54:16 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id h4-20020a17090a710400b0020ae09e9724sm474301pjk.53.2022.10.13.20.54.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Oct 2022 20:54:15 -0700 (PDT) Date: Thu, 13 Oct 2022 20:54:14 -0700 From: Kees Cook To: Andy Lutomirski Cc: Jann Horn , Christian Brauner , "Eric W. Biederman" , Jorge Merlino , Al Viro , Thomas Gleixner , Sebastian Andrzej Siewior , Andrew Morton , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, John Johansen , Paul Moore , James Morris , "Serge E. Hallyn" , Stephen Smalley , Eric Paris , Richard Haines , Casey Schaufler , Xin Long , "David S. Miller" , Todd Kjos , Ondrej Mosnacek , Prashanth Prahlad , Micah Morton , Fenghua Yu , Andrei Vagin , Linux Kernel Mailing List , apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH 1/2] fs/exec: Explicitly unshare fs_struct on exec Message-ID: <202210132052.32AE372@keescook> References: <20221006082735.1321612-1-keescook@chromium.org> <20221006082735.1321612-2-keescook@chromium.org> <20221006090506.paqjf537cox7lqrq@wittgenstein> <2032f766-1704-486b-8f24-a670c0b3cb32@app.fastmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2032f766-1704-486b-8f24-a670c0b3cb32@app.fastmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 13, 2022 at 08:18:04PM -0700, Andy Lutomirski wrote: > But seriously, this makes no sense at all. It should not be possible to exec a program and then, without ptrace, change its cwd out from under it. Do we really need to preserve this behavior? Yup, already abandoned: https://lore.kernel.org/lkml/202210061301.207A20C8E5@keescook/ -- Kees Cook