commit a73f8e21f3f93159bc19e154e8f50891c22c11db upstream.

Louis reported that a static checker was complaining that
the 'dst' variable was set (multiple times) but not used.
This is due to a previous commit having removed the usage
(apparently erroneously), so add it back.

Fixes: a344d6778a98 ("mac80211: allow drivers to support NL80211_SCAN_FLAG_RANDOM_ADDR")
Reported-by: Louis Langholtz <lou_langholtz@me.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There's an issue with the way the RX A-MPDU reorder timer is
deleted that can cause a kernel crash like this:

 * tid_rx is removed - call_rcu(ieee80211_free_tid_rx)
 * station is destroyed
 * reorder timer fires before ieee80211_free_tid_rx() runs,
   accessing the station, thus potentially crashing due to
   the use-after-free

The station deletion is protected by synchronize_net(), but
that isn't enough -- ieee80211_free_tid_rx() need not have
run when that returns (it deletes the timer.) We could use
rcu_barrier() instead of synchronize_net(), but that's much
more expensive.

Instead, to fix this, add a field tracking that the session
is being deleted. In this case, the only re-arming of the
timer happens with the reorder spinlock held, so make that
code not rearm it if the session is being deleted and also
delete the timer after setting that field. This ensures the
timer cannot fire after ___ieee80211_stop_rx_ba_session()
returns, which fixes the problem.

Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

If the AP is confused and starts doing a CSA to the same channel,
just ignore that request instead of trying to act it out since it
was likely sent in error anyway.

In the case of the bug I was investigating the GO was misbehaving
and sending out a beacon with CSA IEs still included after having
actually done the channel switch.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

When a beacon from the AP contains only the ECSA IE, and not a CSA IE
as well, this ECSA IE is not considered for calculating the CRC and
the beacon might be dropped as not being interesting. This is clearly
wrong, it should be handled and the channel switch should be executed.

Fix this by including the ECSA IE ID in the bitmap of interesting IEs.

Reported-by: Gil Tribush <gil.tribush@intel.com>
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Since moving the interface combination checks to mac80211, it's
broken because it now only considers interfaces with an assigned
channel context, so for example any interface that isn't active
can still be up, which is clearly an issue; also, in particular
P2P-Device wdevs are an issue since they never have a chanctx.

Fix this by counting running interfaces instead the ones with a
channel context assigned.

Cc: stable@vger.kernel.org [3.16+]
Fixes: 73de86a38962b ("cfg80211/mac80211: move interface counting for combination check to mac80211")
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
[rewrite commit message, dig out the commit it fixes]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Some APs experience problems when working with
U-APSD. Decreasing the probability of that
happening by using legacy mode for all ACs but VO
isn't enough.

Cisco 4410N originally forced us to enable VO by
default only because it treated non-VO ACs as
legacy.

However some APs (notably Netgear R7000) silently
reclassify packets to different ACs. Since u-APSD
ACs require trigger frames for frame retrieval
clients would never see some frames (e.g. ARP
responses) or would fetch them accidentally after
a long time.

It makes little sense to enable u-APSD queues by
default because it needs userspace applications to
be aware of it to actually take advantage of the
possible additional powersavings. Implicitly
depending on driver autotrigger frame support
doesn't make much sense.

Cc: stable@vger.kernel.org
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The mesh forwarding path was not checking that data
frames were protected when running an encrypted network;
add the necessary check.

Cc: stable@vger.kernel.org
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The current minstrel_ht rate control behavior is somewhat optimistic in
trying to find optimum TX rate. While this is usually fine for normal
Data frames, there are cases where a more conservative set of retry
parameters would be beneficial to make the connection more robust.

EAPOL frames are critical to the authentication and especially the
EAPOL-Key message 4/4 (the last message in the 4-way handshake) is
important to get through to the AP. If that message is lost, the only
recovery mechanism in many cases is to reassociate with the AP and start
from scratch. This can often be avoided by trying to send the frame with
more conservative rate and/or with more link layer retries.

In most cases, minstrel_ht is currently using the initial EAPOL-Key
frames for probing higher rates and this results in only five link layer
transmission attempts (one at high(ish) MCS and four at MCS0). While
this works with most APs, it looks like there are some deployed APs that
may have issues with the EAPOL frames using HT MCS immediately after
association. Similarly, there may be issues in cases where the signal
strength or radio environment is not good enough to be able to get
frames through even at couple of MCS 0 tries.

The best approach for this would likely to be to reduce the TX rate for
the last rate (3rd rate parameter in the set) to a low basic rate (say,
6 Mbps on 5 GHz and 2 or 5.5 Mbps on 2.4 GHz), but doing that cleanly
requires some more effort. For now, we can start with a simple one-liner
that forces the minimum rate to be used for EAPOL frames similarly how
the TX rate is selected for the IEEE 802.11 Management frames. This does
result in a small extra latency added to the cases where the AP would be
able to receive the higher rate, but taken into account how small number
of EAPOL frames are used, this is likely to be insignificant. A future
optimization in the minstrel_ht design can also allow this patch to be
reverted to get back to the more optimized initial TX rate.

It should also be noted that many drivers that do not use minstrel as
the rate control algorithm are already doing similar workarounds by
forcing the lowest TX rate to be used for EAPOL frames.

Cc: stable@vger.kernel.org
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Commit 06d961a8e210 ("mac80211/minstrel: use the new rate control API")
inverted the condition 'if (msr->sample_limit != 0)' to
'if (!msr->sample_limit != 0)'. But it is confusing both to people and
compilers (gcc5):
net/mac80211/rc80211_minstrel.c: In function 'minstrel_get_rate':
net/mac80211/rc80211_minstrel.c:376:26: warning: logical not is only applied to the left hand side of comparison
   if (!msr->sample_limit != 0)
                          ^

Let there be only 'if (!msr->sample_limit)'.

Fixes: 06d961a8e210 ("mac80211/minstrel: use the new rate control API")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

If ieee80211_vif_use_channel() fails, we have to clear
sdata->radar_required (which we might have just set).

Failing to do it results in stale radar_required field
which prevents starting new scan requests.

Reported-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Eliad Peller <eliad@wizery.com>
[use false instead of 0]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>