3.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.b...@intel.com>

commit 3a40414f826a8f1096d9b94c4a53ef91b25ba28d upstream.

Some changes to fix issues with HT40 APs in Korea
and follow-up changes to allow using HT40 even if
the local regulatory database disallows it caused
issues with iwlwifi (and could cause issues with
other devices); iwlwifi firmware would assert if
you tried to connect to an AP that has an invalid
configuration (e.g. using HT40- on channel 140.)

Fix this, while avoiding the "Korean AP" issue by
disabling HT40 and advertising HT20 to the AP
when connecting.

Reported-by: Florian Reitmeir <flor...@reitmeir.org>
Tested-by: Florian Reitmeir <flor...@reitmeir.org>
Signed-off-by: Johannes Berg <johannes.b...@intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 net/mac80211/mlme.c |   30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -3065,22 +3065,32 @@ static int ieee80211_prep_connection(str
                                   ht_cfreq, ht_oper->primary_chan,
                                   cbss->channel->band);
                        ht_oper = NULL;
+               } else {
+                       channel_type = NL80211_CHAN_HT20;
                }
        }
 
-       if (ht_oper) {
-               channel_type = NL80211_CHAN_HT20;
+       if (ht_oper && sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
+               /*
+                * cfg80211 already verified that the channel itself can
+                * be used, but it didn't check that we can do the right
+                * HT type, so do that here as well. If HT40 isn't allowed
+                * on this channel, disable 40 MHz operation.
+                */
 
-               if (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
-                       switch (ht_oper->ht_param &
-                                       IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
-                       case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+               switch (ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
+               case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+                       if (cbss->channel->flags & IEEE80211_CHAN_NO_HT40PLUS)
+                               ifmgd->flags |= IEEE80211_STA_DISABLE_40MHZ;
+                       else
                                channel_type = NL80211_CHAN_HT40PLUS;
-                               break;
-                       case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+                       break;
+               case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+                       if (cbss->channel->flags & IEEE80211_CHAN_NO_HT40MINUS)
+                               ifmgd->flags |= IEEE80211_STA_DISABLE_40MHZ;
+                       else
                                channel_type = NL80211_CHAN_HT40MINUS;
-                               break;
-                       }
+                       break;
                }
        }
 


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