From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D275F2AB21 for ; Wed, 20 Sep 2023 11:59:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58356C433C8; Wed, 20 Sep 2023 11:59:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695211152; bh=Xi/djxjTTjsuzaGipUuNXlLr8j6N0sAa4LuegFk1MzA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nUnx5n6jCwz0sx9HBFzqUE1kDFcTem7zk2FnowNUnf/0LFDXe4eg86QODeEPb3wZI 9c1lC1rMxYRl2mP6QK9LGO7dGWHK0VkCiWW/YwcyS+kPu7LIlFYl6heLKsXE9DjQFQ V8PvUibU6miHgKRY7h5cw/HRzD/RVnWsBSL38xLA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Adam Williamson , Ondrej Mosnacek , Jeff Layton , Paul Moore Subject: [PATCH 6.1 127/139] selinux: fix handling of empty opts in selinux_fs_context_submount() Date: Wed, 20 Sep 2023 13:31:01 +0200 Message-ID: <20230920112840.330159958@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112835.549467415@linuxfoundation.org> References: <20230920112835.549467415@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ondrej Mosnacek commit ccf1dab96be4caed7c5235b1cfdb606ac161b996 upstream. selinux_set_mnt_opts() relies on the fact that the mount options pointer is always NULL when all options are unset (specifically in its !selinux_initialized() branch. However, the new selinux_fs_context_submount() hook breaks this rule by allocating a new structure even if no options are set. That causes any submount created before a SELinux policy is loaded to be rejected in selinux_set_mnt_opts(). Fix this by making selinux_fs_context_submount() leave fc->security set to NULL when there are no options to be copied from the reference superblock. Cc: Reported-by: Adam Williamson Link: https://bugzilla.redhat.com/show_bug.cgi?id=2236345 Fixes: d80a8f1b58c2 ("vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing") Signed-off-by: Ondrej Mosnacek Reviewed-by: Jeff Layton Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- security/selinux/hooks.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2769,14 +2769,20 @@ static int selinux_umount(struct vfsmoun static int selinux_fs_context_submount(struct fs_context *fc, struct super_block *reference) { - const struct superblock_security_struct *sbsec; + const struct superblock_security_struct *sbsec = selinux_superblock(reference); struct selinux_mnt_opts *opts; + /* + * Ensure that fc->security remains NULL when no options are set + * as expected by selinux_set_mnt_opts(). + */ + if (!(sbsec->flags & (FSCONTEXT_MNT|CONTEXT_MNT|DEFCONTEXT_MNT))) + return 0; + opts = kzalloc(sizeof(*opts), GFP_KERNEL); if (!opts) return -ENOMEM; - sbsec = selinux_superblock(reference); if (sbsec->flags & FSCONTEXT_MNT) opts->fscontext_sid = sbsec->sid; if (sbsec->flags & CONTEXT_MNT)