Bluetooth: Ignore key unauthenticated for high security

High security level for pre v2.1 devices requires combination link key
authenticated by at least 16 digit PIN code.

It's also necessary to update key_type and pin_length when the key
exists and is sufficently secured for the connection as there will be
no link key notify event in that case.
Signed-off-by: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@tieto.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/hci_event.c

@@ -2059,11 +2059,23 @@ static inline void hci_link_key_request_evt(struct hci_dev *hdev, struct sk_buff
 	}
 
 	conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &ev->bdaddr);
+	if (conn) {
+		if (key->type == HCI_LK_UNAUTH_COMBINATION &&
+				conn->auth_type != 0xff &&
+				(conn->auth_type & 0x01)) {
+			BT_DBG("%s ignoring unauthenticated key", hdev->name);
+			goto not_found;
+		}
 
-	if (key->type == HCI_LK_UNAUTH_COMBINATION && conn &&
-			conn->auth_type != 0xff && (conn->auth_type & 0x01)) {
-		BT_DBG("%s ignoring unauthenticated key", hdev->name);
-		goto not_found;
+		if (key->type == HCI_LK_COMBINATION && key->pin_len < 16 &&
+				conn->pending_sec_level == BT_SECURITY_HIGH) {
+			BT_DBG("%s ignoring key unauthenticated for high \
+							security", hdev->name);
+			goto not_found;
+		}
+
+		conn->key_type = key->type;
+		conn->pin_length = key->pin_len;
 	}
 
 	bacpy(&cp.bdaddr, &ev->bdaddr);