iwmc3200wifi: add some more range checks

My previous patch added a check to get_key() but missed a couple
other places which need range checks.

The problem here is that wifi drivers have different numbers of keys.
The lower levels assume that they can have up to 4 default keys and
2 management keys but this driver only has the default keys so we
could go past the end of the ->keys[] array.

Signed-off-by: Dan Carpenter <[e-mail]>
Acked-by: Samuel Ortiz <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/iwmc3200wifi/cfg80211.c

···
 				struct key_params *params)
 {
 	struct iwm_priv *iwm = ndev_to_iwm(ndev);
-	struct iwm_key *key = &iwm->keys[key_index];
+	struct iwm_key *key;
 	int ret;
 
 	IWM_DBG_WEXT(iwm, DBG, "Adding key for %pM\n", mac_addr);
 
+	if (key_index >= IWM_NUM_KEYS)
+		return -ENOENT;
+
+	key = &iwm->keys[key_index];
 	memset(key, 0, sizeof(struct iwm_key));
 	ret = iwm_key_init(key, key_index, mac_addr, params);
 	if (ret < 0) {
···
 				u8 key_index, bool pairwise, const u8 *mac_addr)
 {
 	struct iwm_priv *iwm = ndev_to_iwm(ndev);
-	struct iwm_key *key = &iwm->keys[key_index];
+	struct iwm_key *key;
 
+	if (key_index >= IWM_NUM_KEYS)
+		return -ENOENT;
+
+	key = &iwm->keys[key_index];
 	if (!iwm->keys[key_index].key_len) {
 		IWM_DBG_WEXT(iwm, DBG, "Key %d not used\n", key_index);
 		return 0;
···
 	struct iwm_priv *iwm = ndev_to_iwm(ndev);
 
 	IWM_DBG_WEXT(iwm, DBG, "Default key index is: %d\n", key_index);
+
+	if (key_index >= IWM_NUM_KEYS)
+		return -ENOENT;
 
 	if (!iwm->keys[key_index].key_len) {
 		IWM_ERR(iwm, "Key %d not used\n", key_index);