From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757852Ab3BZHcs (ORCPT ); Tue, 26 Feb 2013 02:32:48 -0500 Received: from smtp.outflux.net ([198.145.64.163]:60144 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752458Ab3BZHcr (ORCPT ); Tue, 26 Feb 2013 02:32:47 -0500 Date: Mon, 25 Feb 2013 23:32:25 -0800 From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Evgeniy Polyakov , netdev@vger.kernel.org, Matt Helsley Subject: [PATCH] proc connector: reject unprivileged listener bumps Message-ID: <20130226073225.GA15489@www.outflux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While PROC_CN_MCAST_LISTEN/IGNORE is entirely advisory, it was possible for an unprivileged user to turn off notifications for all listeners by sending PROC_CN_MCAST_IGNORE. Instead, require the same privileges as required for a multicast bind. Signed-off-by: Kees Cook Cc: Evgeniy Polyakov Cc: Matt Helsley Cc: stable@vger.kernel.org --- drivers/connector/cn_proc.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index fce2000..1110478 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -313,6 +313,12 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, (task_active_pid_ns(current) != &init_pid_ns)) return; + /* Can only change if privileged. */ + if (!capable(CAP_NET_ADMIN)) { + err = EPERM; + goto out; + } + mc_op = (enum proc_cn_mcast_op *)msg->data; switch (*mc_op) { case PROC_CN_MCAST_LISTEN: @@ -325,6 +331,8 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, err = EINVAL; break; } + +out: cn_proc_ack(err, msg->seq, msg->ack); } -- 1.7.9.5 -- Kees Cook Chrome OS Security