From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20130318042145.447908587@decadent.org.uk> Date: Mon, 18 Mar 2013 04:21:56 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, Kees Cook , Evgeniy Polyakov , Matt Helsley , "David S. Miller" Subject: [ 12/82] proc connector: reject unprivileged listener bumps In-Reply-To: <20130318042144.234468645@decadent.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit e70ab977991964a5a7ad1182799451d067e62669 upstream. 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 Acked-by: Evgeniy Polyakov Acked-by: Matt Helsley Signed-off-by: David S. Miller [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/connector/cn_proc.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -303,6 +303,12 @@ static void cn_proc_mcast_ctl(struct cn_ if (msg->len != sizeof(*mc_op)) 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: @@ -315,6 +321,8 @@ static void cn_proc_mcast_ctl(struct cn_ err = EINVAL; break; } + +out: cn_proc_ack(err, msg->seq, msg->ack); }