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  1. 30 Nov, 2009 2 commits
    • Johannes Berg's avatar
      mac80211: fix spurious delBA handling · 827d42c9
      Johannes Berg authored 
      Lennert Buytenhek noticed that delBA handling in mac80211
was broken and has remotely triggerable problems, some of
which are due to some code shuffling I did that ended up
changing the order in which things were done -- this was

  commit d75636ef
  Author: Johannes Berg <johannes@sipsolutions.net>
  Date:   Tue Feb 10 21:25:53 2009 +0100

    mac80211: RX aggregation: clean up stop session

and other parts were already present in the original

  commit d92684e6
  Author: Ron Rindjunsky <ron.rindjunsky@intel.com>
  Date:   Mon Jan 28 14:07:22 2008 +0200

      mac80211: A-MPDU Tx add delBA from recipient support

The first problem is that I moved a BUG_ON before various
checks -- thereby making it possible to hit. As the comment
indicates, the BUG_ON can be removed since the ampdu_action
callback must already exist when the state is != IDLE.

The second problem isn't easily exploitable but there's a
race condition due to unconditionally setting the state to
OPERATIONAL when a delBA frame is received, even when no
aggregation session was ever initiated. All the drivers
accept stopping the session even then, but that opens a
race window where crashes could happen before the driver
accepts it. Right now, a WARN_ON may happen with non-HT
drivers, while the race opens only for HT drivers.

For this case, there are two things necessary to fix it:
 1) don't process spurious delBA frames, and be more careful
    about the session state; don't drop the lock

 2) HT drivers need to be prepared to handle a session stop
    even before the session was really started -- this is
    true for all drivers (that support aggregation) but
    iwlwifi which can be fixed easily. The other HT drivers
    (ath9k and ar9170) are behaving properly already.
Reported-by: default avatarLennert Buytenhek <buytenh@marvell.com>
Cc: stable@kernel.org
Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
      827d42c9
    • Johannes Berg's avatar
      mac80211: fix two remote exploits · 4253119a
      Johannes Berg authored 
      Lennert Buytenhek noticed a remotely triggerable problem
in mac80211, which is due to some code shuffling I did
that ended up changing the order in which things were
done -- this was in

  commit d75636ef
  Author: Johannes Berg <johannes@sipsolutions.net>
  Date:   Tue Feb 10 21:25:53 2009 +0100

    mac80211: RX aggregation: clean up stop session

The problem is that the BUG_ON moved before the various
checks, and as such can be triggered.

As the comment indicates, the BUG_ON can be removed since
the ampdu_action callback must already exist when the
state is OPERATIONAL.

A similar code path leads to a WARN_ON in
ieee80211_stop_tx_ba_session, which can also be removed.

Cc: stable@kernel.org [2.6.29+]
Cc: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
      4253119a
  3. 24 Nov, 2009 1 commit
  5. 23 Nov, 2009 12 commits
  7. 21 Nov, 2009 3 commits
  9. 20 Nov, 2009 11 commits
  11. 19 Nov, 2009 10 commits
  13. 18 Nov, 2009 1 commit