From patchwork Thu Jan 21 13:19:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12036497 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 4ED78C433E0 for ; Thu, 21 Jan 2021 14:55:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07645238A1 for ; Thu, 21 Jan 2021 14:55:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732078AbhAUNaz (ORCPT ); Thu, 21 Jan 2021 08:30:55 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:54813 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731290AbhAUN2s (ORCPT ); Thu, 21 Jan 2021 08:28:48 -0500 Received: from ip5f5af0a0.dynamic.kabel-deutschland.de ([95.90.240.160] helo=wittgenstein.fritz.box) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1l2Zuk-0005g7-A7; Thu, 21 Jan 2021 13:22:18 +0000 From: Christian Brauner To: Alexander Viro , Christoph Hellwig , linux-fsdevel@vger.kernel.org Cc: 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 , =?utf-8?q?St=C3=A9phane_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, Christian Brauner Subject: [PATCH v6 28/40] overlayfs: do not mount on top of idmapped mounts Date: Thu, 21 Jan 2021 14:19:47 +0100 Message-Id: <20210121131959.646623-29-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121131959.646623-1-christian.brauner@ubuntu.com> References: <20210121131959.646623-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; i=NKxYXgYXk9li+XoJbSjFMyv4GqDFR/v23AHTzF/JMUU=; m=ypgpaladR0B+T529H8++Mq9zCwr5KRu9f1XcKEdCto8=; p=zW+2p8lkcLUR7GoIjNSpvniO3IeSXEpL+zsJSI4ISsA=; g=020ad20f9fcdeb9417e00e21c4b4fe526c9f39ef X-Patch-Sig: m=pgp; i=christian.brauner@ubuntu.com; s=0x0x91C61BC06578DCA2; b=iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCYAl9pgAKCRCRxhvAZXjcotk/AP93/cy xQTf8sN9k+skVh5513VCqiuPVYRe+4d52LVJKewEAiwgcDIygERxios0PkXXmd8u0IhgfSRGUtmAg fJQ4+AI= Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Prevent overlayfs from being mounted on top of idmapped mounts. Stacking filesystems need to be prevented from being mounted on top of idmapped mounts until they have have been converted to handle this. Link: https://lore.kernel.org/r/20210112220124.837960-40-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Reviewed-by: James Morris --- /* v2 */ patch introduced /* v3 */ - Amir Goldstein : - Move check for idmapped lower layers into ovl_mount_dir_noesc(). - David Howells : - Adapt check after removing mnt_idmapped() helper. /* v4 */ unchanged /* v5 */ unchanged base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837 /* v6 */ unchanged base-commit: 19c329f6808995b142b3966301f217c831e7cf31 --- fs/overlayfs/super.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index c04612b19054..b702c576e783 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -858,6 +858,10 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) pr_err("filesystem on '%s' not supported\n", name); goto out_put; } + if (mnt_user_ns(path->mnt) != &init_user_ns) { + pr_err("idmapped layers are currently not supported\n"); + goto out_put; + } if (!d_is_dir(path->dentry)) { pr_err("'%s' not a directory\n", name); goto out_put;