This is a note to let you know that I've just added the patch titled
mac80211: don't validate unchanged AP bandwidth while tracking
to the 3.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mac80211-don-t-validate-unchanged-ap-bandwidth-while-tracking.patch
and it can be found in the queue-3.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 963a1852fbac4f75a2d938fa2e734ef1e6d4c044 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@xxxxxxxxx>
Date: Fri, 21 Feb 2014 20:34:34 +0100
Subject: mac80211: don't validate unchanged AP bandwidth while tracking
From: Johannes Berg <johannes.berg@xxxxxxxxx>
commit 963a1852fbac4f75a2d938fa2e734ef1e6d4c044 upstream.
The MLME code in mac80211 must track whether or not the AP changed
bandwidth, but if there's no change while tracking it shouldn't do
anything, otherwise regulatory updates can make it impossible to
connect to certain APs if the regulatory database doesn't match the
information from the AP. See the precise scenario described in the
code.
This still leaves some possible problems with CSA or if the AP
actually changed bandwidth, but those cases are less common and
won't completely prevent using it.
This fixes https://bugzilla.kernel.org/show_bug.cgi?id=70881
Reported-and-tested-by: Nate Carlson <kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mac80211/mlme.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -271,6 +271,28 @@ ieee80211_determine_chantype(struct ieee
ret = 0;
out:
+ /*
+ * When tracking the current AP, don't do any further checks if the
+ * new chandef is identical to the one we're currently using for the
+ * connection. This keeps us from playing ping-pong with regulatory,
+ * without it the following can happen (for example):
+ * - connect to an AP with 80 MHz, world regdom allows 80 MHz
+ * - AP advertises regdom US
+ * - CRDA loads regdom US with 80 MHz prohibited (old database)
+ * - the code below detects an unsupported channel, downgrades, and
+ * we disconnect from the AP in the caller
+ * - disconnect causes CRDA to reload world regdomain and the game
+ * starts anew.
+ * (see https://bugzilla.kernel.org/show_bug.cgi?id=70881)
+ *
+ * It seems possible that there are still scenarios with CSA or real
+ * bandwidth changes where a this could happen, but those cases are
+ * less common and wouldn't completely prevent using the AP.
+ */
+ if (tracking &&
+ cfg80211_chandef_identical(chandef, &sdata->vif.bss_conf.chandef))
+ return ret;
+
/* don't print the message below for VHT mismatch if VHT is disabled */
if (ret & IEEE80211_STA_DISABLE_VHT)
vht_chandef = *chandef;
Patches currently in stable-queue which might be from johannes.berg@xxxxxxxxx are
queue-3.13/mac80211-clear-sequence-fragment-number-in-qos-null-frames.patch
queue-3.13/mac80211-fix-association-to-20-40-mhz-vht-networks.patch
queue-3.13/mac80211-send-control-port-protocol-frames-to-the-vo-queue.patch
queue-3.13/iwlwifi-dvm-clear-iwl_sta_ucode_inprogress-when-assoc-fails.patch
queue-3.13/iwlwifi-fix-tx-status-for-aggregated-packets.patch
queue-3.13/iwlwifi-mvm-don-t-warn-when-statistics-are-handled-late.patch
queue-3.13/mac80211-fix-ap-powersave-tx-vs.-wakeup-race.patch
queue-3.13/mac80211-don-t-validate-unchanged-ap-bandwidth-while-tracking.patch
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