mac80211: Scale down to non-HT association with TKIP/WEP as pairwise cipher

As TKIP is not updated to new security needs which arise when
TKIP is used to encrypt A-MPDU aggregated data frames, IEEE802.11n
does not allow any cipher other than CCMP (Which has new extensions
defined) as pairwise cipher between HT peers.

When such configuration (TKIP/WEP in HT) is forced, we still
associate in non-HT mode (11a/b/g).

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 2b890af01ba4..b688425d7555 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -391,10 +391,17 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata,
         }
 
         /* wmm support is a must to HT */
+        /*
+         * IEEE802.11n does not allow TKIP/WEP as pairwise
+         * ciphers in HT mode. We still associate in non-ht
+         * mode (11a/b/g) if any one of these ciphers is
+         * configured as pairwise.
+         */
         if (wmm && (ifsta->flags & IEEE80211_STA_WMM_ENABLED) &&
             sband->ht_cap.ht_supported &&
             (ht_ie = ieee80211_bss_get_ie(bss, WLAN_EID_HT_INFORMATION)) &&
-            ht_ie[1] >= sizeof(struct ieee80211_ht_info)) {
+            ht_ie[1] >= sizeof(struct ieee80211_ht_info) &&
+            (!(ifsta->flags & IEEE80211_STA_TKIP_WEP_USED))) {
                 struct ieee80211_ht_info *ht_info =
                         (struct ieee80211_ht_info *)(ht_ie + 2);
                 u16 cap = sband->ht_cap.cap;