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Patch "nl80211: check netlink protocol in socket release notification" has been added to the 4.5-stable tree

PATCH [email protected] 1 participant 1 message May 1, 2016

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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 4.5-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-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 8f815cdde3e550e10c2736990d791f60c2ce43eb Mon Sep 17 00:00:00 2001

From: Dmitry Ivanov <[email protected]>
Date: Wed, 6 Apr 2016 17:23:18 +0300
Subject: nl80211: check netlink protocol in socket release notification

From: Dmitry Ivanov <[email protected]>

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")
[rewrite commit message]
---
 net/wireless/nl80211.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
net/wireless/nl80211.c +1 -1
@@ -13201,7 +13201,7 @@ 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 [email protected] are

queue-4.5/nl80211-check-netlink-protocol-in-socket-release-notification.patch queue-4.5/netlink-don-t-send-netlink_urelease-for-unbound-sockets.patch