commit 3633ebebab2bbe88124388b7620442315c968e8f upstream.

We already set a station to be associated when peering completes, both
in user space and in the kernel.  Thus we should always have an
associated sta before sending data frames to that station.

Failure to check assoc state can cause crashes in the lower-level driver
due to transmitting unicast data frames before driver sta structures
(e.g. ampdu state in ath9k) are initialized.  This occurred when
forwarding in the presence of fixed mesh paths: frames were transmitted
to stations with whom we hadn't yet completed peering.

Reported-by: Alexis Green <agreen@cococorp.com>
Tested-by: Jesse Jones <jjones@cococorp.com>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

At the last iteration of the loop, j may equal zero and thus
tp_list[j - 1] causes an invalid read.
Change the logic of the loop so that j - 1 is always >= 0.

Cc: stable@vger.kernel.org
Signed-off-by: Adrien Schildknecht <adrien+dev@schischi.me>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The RTNL is required to check for IR-relaxation conditions that allow
more channels to beacon. Export an RTNL locked version of reg_can_beacon
and use it where possible in AP/STA interface type flows, where
IR-relaxation may be applicable.

Fixes: 06f207fc5418 ("cfg80211: change GO_CONCURRENT to IR_CONCURRENT for STA")
Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Although mesh_rx_plink_frame() already checks that frames have enough
bytes for the action code plus another two bytes for capability/reason
code, it doesn't take into account that confirm frames also have an
additional two-byte aid.  As a result, a corrupt frame could cause a
subsequent subtraction to wrap around to ill effect.  Add another
check for this case.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

According to 802.11-2012 8.5.16.3.2 AID comes directly after the
capability bytes in mesh peering confirm frames.  The existing
code, however, was adding a 2 byte offset to this location,
resulting in garbage data going out over the air.  Remove the
offset to fix it.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

If the hardware is unregistered while interfaces are up, mac80211 will
unregister all interfaces, which in turns causes mac80211 to be called
again to remove them all from the driver and eventually shut down the
hardware.

During this shutdown, however, it's currently already unsafe to iterate
the list of interfaces atomically, as the list is manipulated in an
unsafe manner. This puts an undue burden on the driver - it must stop
all its activities before calling ieee80211_unregister_hw(), while in
the normal stop path it can do all cleanup in the stop method. If, for
example, it's using the iteration during RX for some reason, it would
have to stop RX before unregistering to avoid crashes.

Fix this problem by closing all interfaces before unregistering them.
This will cause the driver stop to have completed before we manipulate
the interface list, and after the driver is stopped *and* has called
ieee80211_unregister_hw() it really musn't be iterating any more as
the memory will be freed as well.

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

If for any reason we're in the middle of PS-polling or awake after
TX due to dynamic powersave while going to suspend, go back to save
power. This might cause a response frame to get lost, but since we
can't really wait for it while going to suspend that's still better
than not enabling powersave which would cause higher power usage
during (and possibly even after) suspend.

Note that this really only affects the very few drivers that use
the powersave implementation in mac80211.

Signed-off-by: Chaitanya T K <chaitanya.mgit@gmail.com>
[rewrite misleading commit log]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

When acting as AP and a PS-Poll frame is received
associated station is marked as one in a Service
Period. This state is kept until Tx status for
released frame is reported. While a station is in
Service Period PS-Poll frames are ignored.

However if PS-Poll was received during A-MPDU
teardown it was possible to have the to-be
released frame re-queued back to pending queue.
In such case the frame was stripped of 2 important
flags:

 (a) IEEE80211_TX_CTL_NO_PS_BUFFER
 (b) IEEE80211_TX_STATUS_EOSP

Stripping of (a) led to the frame that was to be
released to be queued back to ps_tx_buf queue. If
station remained to use only PS-Poll frames the
re-queued frame (and new ones) was never actually
transmitted because mac80211 would ignore
subsequent PS-Poll frames due to station being in
Service Period. There was nothing left to clear
the Service Period bit (no xmit -> no tx status ->
no SP end), i.e. the AP would have the station
stuck in Service Period. Beacon TIM would
repeatedly prompt station to poll for frames but
it would get none.

Once (a) is not stripped (b) becomes important
because it's the main condition to clear the
Service Period bit of the station when Tx status
for the released frame is reported back.

This problem was observed with ath9k acting as P2P
GO in some testing scenarios but isn't limited to
it. AP operation with mac80211 based Tx A-MPDU
control combined with clients using PS-Poll frames
is subject to this race.

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

If we don't do this, and we then fail to recreate the debugfs
directory during a mode change, then we will fail later trying
to add stations to this now bogus directory:

BUG: unable to handle kernel NULL pointer dereference at 0000006c
IP: [<c0a92202>] mutex_lock+0x12/0x30
Call Trace:
[<c0678ab4>] start_creating+0x44/0xc0
[<c0679203>] debugfs_create_dir+0x13/0xf0
[<f8a938ae>] ieee80211_sta_debugfs_add+0x6e/0x490 [mac80211]

Cc: stable@kernel.org
Signed-off-by: Tom Hughes <tom@compton.nu>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...