mac80211: don't accept WEP keys other than WEP40 and WEP104

This patch makes mac80211 refuse a WEP key whose length is not WEP40 nor
WEP104.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/wext.c b/net/mac80211/wext.c
index 6106cb7..e840421 100644
--- a/net/mac80211/wext.c
+++ b/net/mac80211/wext.c
@@ -95,6 +95,13 @@
 			}
 		}
 
+		if (alg == ALG_WEP &&
+			key_len != LEN_WEP40 && key_len != LEN_WEP104) {
+			ieee80211_key_free(key);
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
 		ieee80211_key_link(key, sdata, sta);
 
 		if (set_tx_key || (!sta && !sdata->default_key && key))