nl80211: limit to one pairwise cipher for associate()

In this case, only one cipher makes sense, unlike for
connect() where it may be possible to have the card or
driver select.

No changes to mac80211 due to the way the structs are
laid out -- but the loop in net/mac80211/cfg.c will
degrade to just zero or one passes.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/nl80211.c

@@ -3119,7 +3119,8 @@ static int nl80211_authenticate(struct sk_buff *skb, struct genl_info *info)
 }
 
 static int nl80211_crypto_settings(struct genl_info *info,
-				   struct cfg80211_crypto_settings *settings)
+				   struct cfg80211_crypto_settings *settings,
+				   int cipher_limit)
 {
 	settings->control_port = info->attrs[NL80211_ATTR_CONTROL_PORT];
 
@@ -3134,7 +3135,7 @@ static int nl80211_crypto_settings(struct genl_info *info,
 		if (len % sizeof(u32))
 			return -EINVAL;
 
-		if (settings->n_ciphers_pairwise > NL80211_MAX_NR_CIPHER_SUITES)
+		if (settings->n_ciphers_pairwise > cipher_limit)
 			return -EINVAL;
 
 		memcpy(settings->ciphers_pairwise, data, len);
@@ -3247,7 +3248,7 @@ static int nl80211_associate(struct sk_buff *skb, struct genl_info *info)
 		}
 	}
 
-	err = nl80211_crypto_settings(info, &crypto);
+	err = nl80211_crypto_settings(info, &crypto, 1);
 	if (!err)
 		err = cfg80211_mlme_assoc(rdev, dev, chan, bssid, ssid,
 					  ssid_len, ie, ie_len, use_mfp,
@@ -3652,7 +3653,8 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
 
 	connect.privacy = info->attrs[NL80211_ATTR_PRIVACY];
 
-	err = nl80211_crypto_settings(info, &connect.crypto);
+	err = nl80211_crypto_settings(info, &connect.crypto,
+				      NL80211_MAX_NR_CIPHER_SUITES);
 	if (err)
 		return err;
 	rtnl_lock();