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 741D8C43217 for ; Fri, 14 Oct 2022 22:03:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229548AbiJNWD1 convert rfc822-to-8bit (ORCPT ); Fri, 14 Oct 2022 18:03:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229491AbiJNWDZ (ORCPT ); Fri, 14 Oct 2022 18:03:25 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4328E17651D for ; Fri, 14 Oct 2022 15:03:23 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-317-JETZyr0OPF-X3dTWyLgaXA-1; Fri, 14 Oct 2022 23:03:20 +0100 X-MC-Unique: JETZyr0OPF-X3dTWyLgaXA-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.38; Fri, 14 Oct 2022 23:03:18 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.040; Fri, 14 Oct 2022 23:03:18 +0100 From: David Laight To: 'Andy Lutomirski' , Jann Horn , Christian Brauner CC: Kees Cook , "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 Thread-Topic: [PATCH 1/2] fs/exec: Explicitly unshare fs_struct on exec Thread-Index: AQHY33u3rva59bT1H02MahRCUmFfoq4Ocehg Date: Fri, 14 Oct 2022 22:03:18 +0000 Message-ID: References: <20221006082735.1321612-1-keescook@chromium.org> <20221006082735.1321612-2-keescook@chromium.org> <20221006090506.paqjf537cox7lqrq@wittgenstein> <2032f766-1704-486b-8f24-a670c0b3cb32@app.fastmail.com> In-Reply-To: <2032f766-1704-486b-8f24-a670c0b3cb32@app.fastmail.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org From: Andy Lutomirski > Sent: 14 October 2022 04:18 ... > 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? it maybe ok if the exec'ed program also 'bought-in' to the fact that its cwd and open files might get changed. But imagine someone doing it to a login shell! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)