[3.5.y.z extended stable] Patch "mac80211: drop spoofed packets in ad-hoc mode" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    mac80211: drop spoofed packets in ad-hoc mode

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 1b996a71351a8d7a2573cf9f356968720e90b6f7 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd at openwrt.org>
Date: Tue, 17 Sep 2013 11:15:43 +0200
Subject: mac80211: drop spoofed packets in ad-hoc mode

commit 6329b8d917adc077caa60c2447385554130853a3 upstream.

If an Ad-Hoc node receives packets with the Cell ID or its own MAC
address as source address, it hits a WARN_ON in sta_info_insert_check()
With many packets, this can massively spam the logs. One way that this
can easily happen is through having Cisco APs in the area with rouge AP
detection and countermeasures enabled.
Such Cisco APs will regularly send fake beacons, disassoc and deauth
packets that trigger these warnings.

To fix this issue, drop such spoofed packets early in the rx path.

Reported-by: Thomas Huehn <thomas at net.t-labs.tu-berlin.de>
Signed-off-by: Felix Fietkau <nbd at openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/mac80211/rx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index d419c47..ee8f525a 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2823,6 +2823,9 @@ static int prepare_for_handlers(struct ieee80211_rx_data *rx,
 	case NL80211_IFTYPE_ADHOC:
 		if (!bssid)
 			return 0;
+		if (ether_addr_equal(sdata->vif.addr, hdr->addr2) ||
+		    ether_addr_equal(sdata->u.ibss.bssid, hdr->addr2))
+			return 0;
 		if (ieee80211_is_beacon(hdr->frame_control)) {
 			return 1;
 		}
--
1.8.3.2