Patch "nl80211: check netlink protocol in socket release notification" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    nl80211: check netlink protocol in socket release notification

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nl80211-check-netlink-protocol-in-socket-release-notification.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 8f815cdde3e550e10c2736990d791f60c2ce43eb Mon Sep 17 00:00:00 2001
From: Dmitry Ivanov <dmitrijs.ivanovs@ubnt.com>
Date: Wed, 6 Apr 2016 17:23:18 +0300
Subject: nl80211: check netlink protocol in socket release notification

From: Dmitry Ivanov <dmitrijs.ivanovs@ubnt.com>

commit 8f815cdde3e550e10c2736990d791f60c2ce43eb upstream.

A non-privileged user can create a netlink socket with the same port_id as
used by an existing open nl80211 netlink socket (e.g. as used by a hostapd
process) with a different protocol number.

Closing this socket will then lead to the notification going to nl80211's
socket release notification handler, and possibly cause an action such as
removing a virtual interface.

Fix this issue by checking that the netlink protocol is NETLINK_GENERIC.
Since generic netlink has no notifier chain of its own, we can't fix the
problem more generically.

Fixes: 026331c4d9b5 ("cfg80211/mac80211: allow registering for and sending action frames")
Signed-off-by: Dmitry Ivanov <dima@ubnt.com>
[rewrite commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/wireless/nl80211.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -13161,7 +13161,7 @@ static int nl80211_netlink_notify(struct
 	struct wireless_dev *wdev;
 	struct cfg80211_beacon_registration *reg, *tmp;
 
-	if (state != NETLINK_URELEASE)
+	if (state != NETLINK_URELEASE || notify->protocol != NETLINK_GENERIC)
 		return NOTIFY_DONE;
 
 	rcu_read_lock();


Patches currently in stable-queue which might be from dmitrijs.ivanovs@ubnt.com are

queue-4.4/nl80211-check-netlink-protocol-in-socket-release-notification.patch
queue-4.4/netlink-don-t-send-netlink_urelease-for-unbound-sockets.patch