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 56DB1C433DB for ; Tue, 19 Jan 2021 14:30:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18A002070B for ; Tue, 19 Jan 2021 14:30:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403784AbhASO36 (ORCPT ); Tue, 19 Jan 2021 09:29:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732622AbhASJXP (ORCPT ); Tue, 19 Jan 2021 04:23:15 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0FF9C061573; Tue, 19 Jan 2021 01:22:24 -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=8CnqJfggo7kaSxEGLE1dXWml/p5HVDe2QcHu8G5xzpE=; b=B/SF+oWpDEp4Ow/6qcRj1Pjtuc ZTgPRyBXj6uvJk2kKGr1zBt+JZJx3z/Ge42kzCCxBwj24xTNtoscGGc8tBtyTWazzdta2HMlw2rxX GBqbhVRzbwxIbrObTT5WMZL/+bEHg4a7SpO6xwoijVGm9hlDxYcVFxT4RwlU4nqM8xZxyzScZISk3 VCXLak/ZtbHGP+jNdjz9dqXFHrMWmmXZHfzHAdLnIquDP0kLPFjkHlVLKeFGqwpKVTHj+m6UwvADV qrwMy1bfJkq7V7gHv7Ej0mYvbwwatOwTL22s0adqKcO3VN4V5pG1ioZ7deJCA9RINgyNMj+FTYPJd 2C3UBbrg==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l1nDF-00E6mf-Sl; Tue, 19 Jan 2021 09:22:11 +0000 Date: Tue, 19 Jan 2021 09:22:09 +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 10/42] capability: handle idmapped mounts Message-ID: <20210119092209.GB3361757@infradead.org> References: <20210112220124.837960-1-christian.brauner@ubuntu.com> <20210112220124.837960-11-christian.brauner@ubuntu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210112220124.837960-11-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 11:00:52PM +0100, Christian Brauner wrote: > In order to determine whether a caller holds privilege over a given > inode the capability framework exposes the two helpers > privileged_wrt_inode_uidgid() and capable_wrt_inode_uidgid(). The former > verifies that the inode has a mapping in the caller's user namespace and > the latter additionally verifies that the caller has the requested > capability in their current user namespace. > If the inode is accessed through an idmapped mount we simply need to map > it according to the mount's user namespace. Afterwards the checks are > identical to non-idmapped inodes. If the initial user namespace is > passed all operations are a nop so non-idmapped mounts will not see a > change in behavior and will also not see any performance impact. This adds a bunch of pointless > 80 char lines, that would be nice to fix up. Otherwise looks good: Reviewed-by: Christoph Hellwig