[MAC80211]: ignore key index on pairwise key (WEP only)

Work-around for broken APs that use a non-zero key index for WEP
pairwise keys. With this patch, WEP encryption only is exempt from
providing a zero key index.
Signed-off-by: Volker Braun <volker.braun@physik.hu-berlin.de>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mac80211/ieee80211_ioctl.c

@@ -73,17 +73,23 @@ static int ieee80211_set_encryption(struct net_device *dev, u8 *sta_addr,
 
 	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
-	if (is_broadcast_ether_addr(sta_addr)) {
-		sta = NULL;
-		if (idx >= NUM_DEFAULT_KEYS) {
+	if (idx < 0 || idx >= NUM_DEFAULT_KEYS) {
 		printk(KERN_DEBUG "%s: set_encrypt - invalid idx=%d\n",
 		       dev->name, idx);
 		return -EINVAL;
 	}
+
+	if (is_broadcast_ether_addr(sta_addr)) {
+		sta = NULL;
 		key = sdata->keys[idx];
 	} else {
 		set_tx_key = 0;
-		if (idx != 0) {
+		/*
+		 * According to the standard, the key index of a pairwise
+		 * key must be zero. However, some AP are broken when it
+		 * comes to WEP key indices, so we work around this.
+		 */
+		if (idx != 0 && alg != ALG_WEP) {
 			printk(KERN_DEBUG "%s: set_encrypt - non-zero idx for "
 			       "individual key\n", dev->name);
 			return -EINVAL;