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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 4380FC41518 for ; Tue, 19 Jan 2021 22:40:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E8C0230FE for ; Tue, 19 Jan 2021 22:40:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403996AbhASOcH (ORCPT ); Tue, 19 Jan 2021 09:32:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387582AbhASJeW (ORCPT ); Tue, 19 Jan 2021 04:34:22 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D082C061574; Tue, 19 Jan 2021 01:33:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=1acN46MpaPD0Uo/eaBisBkwf/+vpr3p34PmGVNKLyj4=; b=KxUOlItbLKC0Avomi+19Gi2mcV gmWIZesVp04Vx271TV9b12XH2uIVL4VVV+bLwXEwvpVa+rJzPrNT0nHJhRYqIYGgwv9CtShnFhybV vqjmZOZPQr8XuVGUTKyPw1JBpMikjjY8GUzwj3sGB0H4dPdwLCC70zMRdWdSTED2xkchcQhXyfqPB AfcImiORPYISXJfLt8J2JIAdaMcaJK/Qc+dlv3Jnyu6CP+oVkJ3k/6iHn+N4D7s2ryGs0vpixWCDF UXeDZ17iiJ8GPw1BHIsY66OMlUpie2S7mvML6r33SJXdD0zMc6Ya/tOubD5xLSxmpKc+Nbx8PUSIK ZGweAYaQ==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l1nO8-00E7YL-MF; Tue, 19 Jan 2021 09:33:28 +0000 Date: Tue, 19 Jan 2021 09:33:24 +0000 From: Christoph Hellwig To: Christian Brauner Cc: Alexander Viro , Christoph Hellwig , linux-fsdevel@vger.kernel.org, John Johansen , James Morris , 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 , St??phane 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, Christoph Hellwig Subject: Re: [PATCH v5 19/42] namei: handle idmapped mounts in may_*() helpers Message-ID: <20210119093324.GD3364550@infradead.org> References: <20210112220124.837960-1-christian.brauner@ubuntu.com> <20210112220124.837960-20-christian.brauner@ubuntu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210112220124.837960-20-christian.brauner@ubuntu.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Jan 12, 2021 at 11:01:01PM +0100, 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. Looks good, Reviewed-by: Christoph Hellwig