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Commit 8f815cdd authored by Dmitry Ivanov's avatar Dmitry Ivanov Committed by Johannes Berg
Browse files

nl80211: check netlink protocol in socket release notification 



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: 026331c4 ("cfg80211/mac80211: allow registering for and sending action frames")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDmitry Ivanov <dima@ubnt.com>
[rewrite commit message]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 30d237a6

net/wireless/nl80211.c

+1 −1
Original line number Diff line number Diff line
@@ -13216,7 +13216,7 @@ static int nl80211_netlink_notify(struct notifier_block * nb, 
	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();