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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 A0670C43331 for ; Fri, 22 Jan 2021 03:49:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71F8F23899 for ; Fri, 22 Jan 2021 03:49:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726434AbhAVDte (ORCPT ); Thu, 21 Jan 2021 22:49:34 -0500 Received: from namei.org ([65.99.196.166]:52776 "EHLO mail.namei.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726030AbhAVDtc (ORCPT ); Thu, 21 Jan 2021 22:49:32 -0500 Received: from localhost (localhost [127.0.0.1]) by mail.namei.org (Postfix) with ESMTPS id 1847E8CE; Fri, 22 Jan 2021 03:47:59 +0000 (UTC) Date: Fri, 22 Jan 2021 14:47:59 +1100 (AEDT) From: James Morris To: Christian Brauner cc: Alexander Viro , Christoph Hellwig , linux-fsdevel@vger.kernel.org, John Johansen , Mimi Zohar , Dmitry Kasatkin , Stephen Smalley , Casey Schaufler , Arnd Bergmann , Andreas Dilger , OGAWA Hirofumi , Geoffrey Thomas , Mrunal Patel , Josh Triplett , Andy Lutomirski , Theodore Tso , Alban Crequy , Tycho Andersen , David Howells , James Bottomley , Seth Forshee , =?ISO-8859-15?Q?St=E9phane_Graber?= , Linus Torvalds , Aleksa Sarai , Lennart Poettering , "Eric W. Biederman" , smbarber@chromium.org, Phil Estes , Serge Hallyn , Kees Cook , Todd Kjos , Paul Moore , Jonathan Corbet , containers@lists.linux-foundation.org, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-integrity@vger.kernel.org, selinux@vger.kernel.org Subject: Re: [PATCH v6 12/40] namei: handle idmapped mounts in may_*() helpers In-Reply-To: <20210121131959.646623-13-christian.brauner@ubuntu.com> Message-ID: <2ec5e6b6-768c-dad-3365-53c129579eb@namei.org> References: <20210121131959.646623-1-christian.brauner@ubuntu.com> <20210121131959.646623-13-christian.brauner@ubuntu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Thu, 21 Jan 2021, Christian Brauner wrote: > The may_follow_link(), may_linkat(), may_lookup(), may_open(), > may_o_create(), may_create_in_sticky(), may_delete(), and may_create() > helpers determine whether the caller is privileged enough to perform the > associated operations. Let them handle idmapped mounts by mapping the > inode or fsids according to the mount's user namespace. Afterwards the > checks are identical to non-idmapped inodes. The patch takes care to > retrieve the mount's user namespace right before performing permission > checks and passing it down into the fileystem so the user namespace > can't change in between by someone idmapping a mount that is currently > not idmapped. If the initial user namespace is passed nothing changes so > non-idmapped mounts will see identical behavior as before. > > Link: https://lore.kernel.org/r/20210112220124.837960-20-christian.brauner@ubuntu.com > Cc: Christoph Hellwig > Cc: David Howells > Cc: Al Viro > Cc: linux-fsdevel@vger.kernel.org > Reviewed-by: Christoph Hellwig > Signed-off-by: Christian Brauner Reviewed-by: James Morris -- James Morris