mwifiex: Prevent memory corruption handling keys

The length of the key comes from the network and it's a 16 bit number.  It
needs to be capped to prevent a buffer overflow.

Fixes: 5e6e3a92 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Ganapathi Bhat <ganapathi.bhat@nxp.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200708115857.GA13729@mwanda

drivers/net/wireless/marvell/mwifiex/sta_cmdresp.c

@@ -580,6 +580,11 @@ static int mwifiex_ret_802_11_key_material_v1(struct mwifiex_private *priv,
 {
 	struct host_cmd_ds_802_11_key_material *key =
 						&resp->params.key_material;
+	int len;
+
+	len = le16_to_cpu(key->key_param_set.key_len);
+	if (len > sizeof(key->key_param_set.key))
+		return -EINVAL;
 
 	if (le16_to_cpu(key->action) == HostCmd_ACT_GEN_SET) {
 		if ((le16_to_cpu(key->key_param_set.key_info) & KEY_MCAST)) {
@@ -593,9 +598,8 @@ static int mwifiex_ret_802_11_key_material_v1(struct mwifiex_private *priv,
 
 	memset(priv->aes_key.key_param_set.key, 0,
 	       sizeof(key->key_param_set.key));
-	priv->aes_key.key_param_set.key_len = key->key_param_set.key_len;
-	memcpy(priv->aes_key.key_param_set.key, key->key_param_set.key,
-	       le16_to_cpu(priv->aes_key.key_param_set.key_len));
+	priv->aes_key.key_param_set.key_len = cpu_to_le16(len);
+	memcpy(priv->aes_key.key_param_set.key, key->key_param_set.key, len);
 
 	return 0;
 }
@@ -610,9 +614,14 @@ static int mwifiex_ret_802_11_key_material_v2(struct mwifiex_private *priv,
 					      struct host_cmd_ds_command *resp)
 {
 	struct host_cmd_ds_802_11_key_material_v2 *key_v2;
-	__le16 len;
+	int len;
 
 	key_v2 = &resp->params.key_material_v2;
+
+	len = le16_to_cpu(key_v2->key_param_set.key_params.aes.key_len);
+	if (len > WLAN_KEY_LEN_CCMP)
+		return -EINVAL;
+
 	if (le16_to_cpu(key_v2->action) == HostCmd_ACT_GEN_SET) {
 		if ((le16_to_cpu(key_v2->key_param_set.key_info) & KEY_MCAST)) {
 			mwifiex_dbg(priv->adapter, INFO, "info: key: GTK is set\n");
@@ -628,10 +637,9 @@ static int mwifiex_ret_802_11_key_material_v2(struct mwifiex_private *priv,
 	memset(priv->aes_key_v2.key_param_set.key_params.aes.key, 0,
 	       WLAN_KEY_LEN_CCMP);
 	priv->aes_key_v2.key_param_set.key_params.aes.key_len =
-				key_v2->key_param_set.key_params.aes.key_len;
-	len = priv->aes_key_v2.key_param_set.key_params.aes.key_len;
+				cpu_to_le16(len);
 	memcpy(priv->aes_key_v2.key_param_set.key_params.aes.key,
-	       key_v2->key_param_set.key_params.aes.key, le16_to_cpu(len));
+	       key_v2->key_param_set.key_params.aes.key, len);
 
 	return 0;
 }