From patchwork Tue Jan 12 22:01:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12015355 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 25C21C10DC3 for ; Tue, 12 Jan 2021 22:17:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E18F623127 for ; Tue, 12 Jan 2021 22:17:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437183AbhALWPu (ORCPT ); Tue, 12 Jan 2021 17:15:50 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:44658 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436785AbhALWPD (ORCPT ); Tue, 12 Jan 2021 17:15:03 -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 1kzRm8-0003bd-Cp; Tue, 12 Jan 2021 22:04:28 +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 , Christoph Hellwig Subject: [PATCH v5 38/42] ecryptfs: do not mount on top of idmapped mounts Date: Tue, 12 Jan 2021 23:01:20 +0100 Message-Id: <20210112220124.837960-39-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210112220124.837960-1-christian.brauner@ubuntu.com> References: <20210112220124.837960-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; i=ghv/kMxBjWVz72L+xFuQBh/xSmPaVl07FCNHzoGv4Rk=; m=RIGatARQovooPnBDA/H8CPhh/6JweIoTP2cJrYbkVCI=; p=y+aaA7asfnKesPwKpXtBf+Gzv/rdSr5LpwUc8kyT8VY=; g=c814c6483a8755fc91bca27ebabaa2b2beaaec75 X-Patch-Sig: m=pgp; i=christian.brauner@ubuntu.com; s=0x0x91C61BC06578DCA2; b=iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCX/4YuQAKCRCRxhvAZXjcoqzRAQCd5MD U/DLZ1XXAd4SCdch11W5V9WgLBiIRycGgQlrdPQD+INTClteAZTqsKDQe0S15bIP8C5YjBes4H9Wk KS/yCwU= Precedence: bulk List-ID: Prevent ecryptfs from being mounted on top of idmapped mounts until we have ported it to handle this case and added proper testing for it. Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- /* v2 */ patch introduced /* v3 */ - David Howells : - Adapt check after removing mnt_idmapped() helper. /* v4 */ unchanged /* v5 */ base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837 - Christoph Hellwig : - Use new file_userns_helper(). --- fs/ecryptfs/main.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index e63259fdef28..cdf40a54a35d 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -531,6 +531,12 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags goto out_free; } + if (mnt_user_ns(path.mnt) != &init_user_ns) { + rc = -EINVAL; + printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n"); + goto out_free; + } + if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) { rc = -EPERM; printk(KERN_ERR "Mount of device (uid: %d) not owned by "