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[23.128.96.18]) by mx.google.com with ESMTP id i26si11325811edv.319.2021.06.14.03.49.27; Mon, 14 Jun 2021 03:49:49 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=d7WcbYQF; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234252AbhFNKt0 (ORCPT + 99 others); Mon, 14 Jun 2021 06:49:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:47606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233066AbhFNKmZ (ORCPT ); Mon, 14 Jun 2021 06:42:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8A42B61433; Mon, 14 Jun 2021 10:35:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623666938; bh=hOaLsk8luCrfyt/i8zPTrnJq7mDdQimt/9ZzMKThkjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d7WcbYQF7YsrF4AiBG4pTjM0qfaWSBjQMc1RGgf5PCgG4zma5IqHseLIM3Lw8bcPj jdgFdyqK8CnqeBJR67EKL0GB0FfPrHN7JZ75MmhTJj1+XZbO9Li/FLN+Dp3V4pcmvA DSiZbVrfPrFNjYcgW2ntMdXATrdK1kPewyFEYSlQ= 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 4.19 34/67] cgroup1: dont allow \n in renaming Date: Mon, 14 Jun 2021 12:27:17 +0200 Message-Id: <20210614102644.922992967@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210614102643.797691914@linuxfoundation.org> References: <20210614102643.797691914@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 @@ -849,6 +849,10 @@ 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)