mac80211: ignore non-bcast mcast deauth/disassoc franes
authorChristian Lamparter <chunkeey@googlemail.com>
Mon, 29 Nov 2010 19:53:23 +0000 (20:53 +0100)
committerJohn W. Linville <linville@tuxdriver.com>
Tue, 30 Nov 2010 18:23:06 +0000 (13:23 -0500)
commit2c31333a8fde7e26936a9f5371d02ff12c490993
tree75bb0fc716caa240e7afc0245da0b5089bd3e420
parentcf63495d0dbe435b475a44672f5dee150da6471b
mac80211: ignore non-bcast mcast deauth/disassoc franes

This patch fixes an curious issue due to insufficient
rx frame filtering.

Saqeb Akhter reported frequent disconnects while streaming
videos over samba: <http://marc.info/?m=128600031109136>
> [ 1166.512087] wlan1: deauthenticated from 30:46:9a:10:49:f7 (Reason: 7)
> [ 1526.059997] wlan1: deauthenticated from 30:46:9a:10:49:f7 (Reason: 7)
> [ 2125.324356] wlan1: deauthenticated from 30:46:9a:10:49:f7 (Reason: 7)
> [...]

The reason is that the device generates frames with slightly
bogus SA/TA addresses.

e.g.:
 [ 2314.402316] Ignore 9f:1f:31:f8:64:ff
 [ 2314.402321] Ignore 9f:1f:31:f8:64:ff
 [ 2352.453804] Ignore 0d:1f:31:f8:64:ff
 [ 2352.453808] Ignore 0d:1f:31:f8:64:ff
     ^^ the group-address flag is set!
 (the correct SA/TA would be: 00:1f:31:f8:64:ff)

Since the AP does not know from where the frames come, it
generates a DEAUTH response for the (invalid) mcast address.
This mcast deauth frame then passes through all filters and
tricks the stack into thinking that the AP brutally kicked
us!

This patch fixes the problem by simply ignoring
non-broadcast, group-addressed deauth/disassoc frames.

Cc: Jouni Malinen <j@w1.fi>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reported-by: Saqeb Akhter <saqeb.akhter@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
net/mac80211/rx.c