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=-13.0 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 A4774C43457 for ; Mon, 27 Jul 2020 14:29:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8288F20838 for ; Mon, 27 Jul 2020 14:29:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732068AbgG0OXX (ORCPT ); Mon, 27 Jul 2020 10:23:23 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:51904 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732044AbgG0OXT (ORCPT ); Mon, 27 Jul 2020 10:23:19 -0400 X-Greylist: delayed 454 seconds by postgrey-1.27 at vger.kernel.org; Mon, 27 Jul 2020 10:23:17 EDT Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id DD21220A04; Mon, 27 Jul 2020 14:15:41 +0000 (UTC) From: Alexey Gladkov To: LKML Cc: Linux FS Devel , Alexander Viro , Alexey Gladkov , "Eric W . Biederman" , Kees Cook Subject: [PATCH v1 2/2] Show /proc/self/net only for CAP_NET_ADMIN Date: Mon, 27 Jul 2020 16:14:11 +0200 Message-Id: <20200727141411.203770-3-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200727141411.203770-1-gladkov.alexey@gmail.com> References: <20200727141411.203770-1-gladkov.alexey@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Mon, 27 Jul 2020 14:15:42 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Show /proc/self/net only for CAP_NET_ADMIN if procfs is mounted with subset=pid option in user namespace. This is done to avoid possible information leakage. Signed-off-by: Alexey Gladkov --- fs/proc/proc_net.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c index dba63b2429f0..11fa2c4b3529 100644 --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -275,6 +275,12 @@ static struct net *get_proc_task_net(struct inode *dir) struct task_struct *task; struct nsproxy *ns; struct net *net = NULL; + struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb); + + if ((fs_info->pidonly == PROC_PIDONLY_ON) && + (current_user_ns() != &init_user_ns) && + !capable(CAP_NET_ADMIN)) + return net; rcu_read_lock(); task = pid_task(proc_pid(dir), PIDTYPE_PID); -- 2.25.4