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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50F4FC433F5 for ; Wed, 23 Feb 2022 18:07:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243673AbiBWSIL (ORCPT ); Wed, 23 Feb 2022 13:08:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243808AbiBWSH6 (ORCPT ); Wed, 23 Feb 2022 13:07:58 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FC8347059 for ; Wed, 23 Feb 2022 10:07:30 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DFD4DB8213C for ; Wed, 23 Feb 2022 18:07:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2162FC340E7; Wed, 23 Feb 2022 18:07:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1645639647; bh=YbjYIBhR1HjxfOfUt/6f9pPKawMqR70iFjlCdbKbXeY=; h=Subject:To:Cc:From:Date:From; b=NzO9GnVjUUD8t7HmvdcbzZliDw61u9q6VGMtG8C0v0PvJaqD1vUrTOUcWh0hOqP+N G5TOKV2mXaiJ8ua5npJzL1KNxOQuArcQXC32mayogXQyQ30nnGfoRz/db5ywQPAMCE mJfTgtCv82CeU8dGJvEjjEJk6Cx1tS13rw5Dwg34= Subject: FAILED: patch "[PATCH] cgroup-v1: Correct privileges check in release_agent writes" failed to apply to 5.10-stable tree To: mkoutny@suse.com, masami.ichikawa@cybertrust.co.jp, tj@kernel.org Cc: From: Date: Wed, 23 Feb 2022 19:07:12 +0100 Message-ID: <1645639632780@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 467a726b754f474936980da793b4ff2ec3e382a7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Michal=20Koutn=C3=BD?= Date: Thu, 17 Feb 2022 17:11:28 +0100 Subject: [PATCH] cgroup-v1: Correct privileges check in release_agent writes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The idea is to check: a) the owning user_ns of cgroup_ns, b) capabilities in init_user_ns. The commit 24f600856418 ("cgroup-v1: Require capabilities to set release_agent") got this wrong in the write handler of release_agent since it checked user_ns of the opener (may be different from the owning user_ns of cgroup_ns). Secondly, to avoid possibly confused deputy, the capability of the opener must be checked. Fixes: 24f600856418 ("cgroup-v1: Require capabilities to set release_agent") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/stable/20220216121142.GB30035@blackbody.suse.cz/ Signed-off-by: Michal Koutný Reviewed-by: Masami Ichikawa(CIP) Signed-off-by: Tejun Heo diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 0e877dbcfeea..afc6c0e9c966 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -546,6 +546,7 @@ static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct cgroup *cgrp; + struct cgroup_file_ctx *ctx; BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX); @@ -553,8 +554,9 @@ static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of, * Release agent gets called with all capabilities, * require capabilities to set release agent. */ - if ((of->file->f_cred->user_ns != &init_user_ns) || - !capable(CAP_SYS_ADMIN)) + ctx = of->priv; + if ((ctx->ns->user_ns != &init_user_ns) || + !file_ns_capable(of->file, &init_user_ns, CAP_SYS_ADMIN)) return -EPERM; cgrp = cgroup_kn_lock_live(of->kn, false);