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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 E2E24C43143 for ; Sat, 29 Sep 2018 19:46:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AAD77206B2 for ; Sat, 29 Sep 2018 19:46:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PPu01VWs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AAD77206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728015AbeI3CQc (ORCPT ); Sat, 29 Sep 2018 22:16:32 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:38078 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727405AbeI3CQc (ORCPT ); Sat, 29 Sep 2018 22:16:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=d+Pi6r1Xb+XbBfameMEsWsdZZO+w1ilk/ee61pLllTo=; b=PPu01VWsmZCdrM/rcgdEM3Cdu iu2NiBA4bqfMDkHUgm5EGmXYNQeUm0xsCUQRfYd4w4mPY8KaeoCQ/u7EV/uFwZI0u18DtwG/ju4Vm odl35rs99dqF8g4wt+q+gibdq9Aog+KUaKOxQxAb1B/narPjSYJ4tvUGKHjcCJ4zEGoQjGw6B+Dnc uh4t8IZR7xc00AMqpiGCrbt+kVyxG3+xJdMR+7yX/WQKKg0MlKo1ZdwCYXeXyCs6AQtku43D3Lcuj qPV94fCwoiE8tS0A5pJrFatZBWgRnkSvMQz+aEt2hslIV5mxBc8AuvNvWnvnTQKMt1Gk+D5lIPOe6 y8OXUKafQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1g6LAD-0002dY-Ip; Sat, 29 Sep 2018 19:44:29 +0000 Date: Sat, 29 Sep 2018 12:44:29 -0700 From: Matthew Wilcox To: Andy Lutomirski Cc: Aleksa Sarai , Jeff Layton , "J. Bruce Fields" , Al Viro , Arnd Bergmann , Shuah Khan , David Howells , Andy Lutomirski , Christian Brauner , Eric Biederman , Tycho Andersen , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, dev@opencontainers.org, containers@lists.linux-foundation.org Subject: Re: [PATCH 0/3] namei: implement various scoping AT_* flags Message-ID: <20180929194429.GA1702@bombadil.infradead.org> References: <20180929103453.12025-1-cyphar@cyphar.com> <1EE20CA2-4C8B-4A80-B613-0277D92B376D@amacapital.net> <20180929154551.jsi6dt3xjxdxoqeh@ryuk> <9D01A225-05BE-4B4A-873A-94168D17F687@amacapital.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9D01A225-05BE-4B4A-873A-94168D17F687@amacapital.net> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 29, 2018 at 09:34:24AM -0700, Andy Lutomirski wrote: > Also, as a perhaps-silly suggestion: if you end up adding a new > syscall, I can see a use for a mode that does the path walk but, rather > than failing on a disallowed link, stops early and indicates where it > stopped. Then web servers, samba, etc can more efficiently implement > custom behavior when links are encountered. And it may also be useful > to have a variant of AT_THIS_ROOT where trying to escape is an error > instead of having it just get stuck at the root. AT_USER_LINKS indicating that userspace wants to resolve symlinks themselves?