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 X-Spam-Level: X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 BED30C2B9F4 for ; Mon, 14 Jun 2021 10:44:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3312611C1 for ; Mon, 14 Jun 2021 10:44:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233878AbhFNKqU (ORCPT ); Mon, 14 Jun 2021 06:46:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:46962 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233971AbhFNKjW (ORCPT ); Mon, 14 Jun 2021 06:39:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3528561438; Mon, 14 Jun 2021 10:34:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623666856; bh=VL9TgoyM1NLxGaErLV4tti8G04EllZFgLviCImGqyiY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ycx/oqg99RjS40Phgx9wqLZpodoZMVmInO1ykcYKMKhTQkgU5LEh1RH2oJOCmRf5P F+ZKE3968zQ9iHOFsWoheLzojZOXzntJZ8L2EsEgOxKhP4H/yUWbjqHElk8cfkMzZp a2Kw6dfEfnSlLVoBc4KUPWMvnHYS89P9o8kh6oHg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Kuznetsov , Andrey Krasichkov , Dmitry Yakunin , Tejun Heo Subject: [PATCH 4.14 26/49] cgroup1: dont allow \n in renaming Date: Mon, 14 Jun 2021 12:27:19 +0200 Message-Id: <20210614102642.721065011@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210614102641.857724541@linuxfoundation.org> References: <20210614102641.857724541@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexander Kuznetsov commit b7e24eb1caa5f8da20d405d262dba67943aedc42 upstream. cgroup_mkdir() have restriction on newline usage in names: $ mkdir $'/sys/fs/cgroup/cpu/test\ntest2' mkdir: cannot create directory '/sys/fs/cgroup/cpu/test\ntest2': Invalid argument But in cgroup1_rename() such check is missed. This allows us to make /proc//cgroup unparsable: $ mkdir /sys/fs/cgroup/cpu/test $ mv /sys/fs/cgroup/cpu/test $'/sys/fs/cgroup/cpu/test\ntest2' $ echo $$ > $'/sys/fs/cgroup/cpu/test\ntest2' $ cat /proc/self/cgroup 11:pids:/ 10:freezer:/ 9:hugetlb:/ 8:cpuset:/ 7:blkio:/user.slice 6:memory:/user.slice 5:net_cls,net_prio:/ 4:perf_event:/ 3:devices:/user.slice 2:cpu,cpuacct:/test test2 1:name=systemd:/ 0::/ Signed-off-by: Alexander Kuznetsov Reported-by: Andrey Krasichkov Acked-by: Dmitry Yakunin Cc: stable@vger.kernel.org Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- kernel/cgroup/cgroup-v1.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -861,6 +861,10 @@ static int cgroup1_rename(struct kernfs_ struct cgroup *cgrp = kn->priv; int ret; + /* do not accept '\n' to prevent making /proc//cgroup unparsable */ + if (strchr(new_name_str, '\n')) + return -EINVAL; + if (kernfs_type(kn) != KERNFS_DIR) return -ENOTDIR; if (kn->parent != new_parent)