mac80211: continue using disabled channels while connected

In case the AP has different regulatory information than we do,
it can happen that we connect to an AP based on e.g. the world
roaming regulatory data, and then update our database with the
AP's country information disables the channel the AP is using.
If this happens on an HT AP, the bandwidth tracking code will
hit the WARN_ON() and disconnect. Since that's not very useful,
ignore the channel-disable flag in bandwidth tracking.

Cc: stable@vger.kernel.org
Reported-by: Chris Wright <chrisw@sous-sol.org>
Tested-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 077a953608307427e2a8e5cb09dac0350fb1e0f6..cc9e02d79b550106ee07b6aca48ffa9e18081a45 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -335,8 +335,17 @@ out:
        if (ret & IEEE80211_STA_DISABLE_VHT)
                vht_chandef = *chandef;
 
+       /*
+        * Ignore the DISABLED flag when we're already connected and only
+        * tracking the APs beacon for bandwidth changes - otherwise we
+        * might get disconnected here if we connect to an AP, update our
+        * regulatory information based on the AP's country IE and the
+        * information we have is wrong/outdated and disables the channel
+        * that we're actually using for the connection to the AP.
+        */
        while (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
-                                       IEEE80211_CHAN_DISABLED)) {
+                                       tracking ? 0 :
+                                                  IEEE80211_CHAN_DISABLED)) {
                if (WARN_ON(chandef->width == NL80211_CHAN_WIDTH_20_NOHT)) {
                        ret = IEEE80211_STA_DISABLE_HT |
                              IEEE80211_STA_DISABLE_VHT;