From patchwork Sun Nov 15 10:37:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 11906191 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8A5B2174A for ; Sun, 15 Nov 2020 10:43:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B89E23A32 for ; Sun, 15 Nov 2020 10:43:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726849AbgKOKmq (ORCPT ); Sun, 15 Nov 2020 05:42:46 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:59336 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726826AbgKOKmK (ORCPT ); Sun, 15 Nov 2020 05:42:10 -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 1keFS1-0000Kt-Dq; Sun, 15 Nov 2020 10:40:05 +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 , Jann Horn , Seth Forshee , =?utf-8?q?St=C3=A9phane_Graber?= , Aleksa Sarai , Lennart Poettering , "Eric W. Biederman" , smbarber@chromium.org, Phil Estes , Serge Hallyn , Kees Cook , Todd Kjos , Jonathan Corbet , containers@lists.linux-foundation.org, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org, linux-ext4@vger.kernel.org, linux-audit@redhat.com, linux-integrity@vger.kernel.org, selinux@vger.kernel.org, Christian Brauner , Christoph Hellwig Subject: [PATCH v2 36/39] overlayfs: do not mount on top of idmapped mounts Date: Sun, 15 Nov 2020 11:37:15 +0100 Message-Id: <20201115103718.298186-37-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201115103718.298186-1-christian.brauner@ubuntu.com> References: <20201115103718.298186-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Precedence: bulk List-ID: Prevent overlayfs 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 --- fs/overlayfs/super.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 0d4f2baf6836..3cacc3d3fb65 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -1708,6 +1708,12 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, if (err) goto out_err; + if (mnt_idmapped(stack[i].mnt)) { + err = -EINVAL; + pr_err("idmapped lower layers are currently unsupported\n"); + goto out_err; + } + lower = strchr(lower, '\0') + 1; } @@ -1939,6 +1945,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) if (err) goto out_err; + if (mnt_idmapped(upperpath.mnt)) { + err = -EINVAL; + pr_err("idmapped lower layers are currently unsupported\n"); + goto out_err; + } + err = ovl_get_workdir(sb, ofs, &upperpath); if (err) goto out_err;