Bluetooth: Add smp_ltk_sec_level() helper function

There are several places that need to determine the security level that
an LTK can provide. This patch adds a convenience function for this to
help make the code more readable.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_event.c

@@ -4506,10 +4506,7 @@ static void hci_le_ltk_request_evt(struct hci_dev *hdev, struct sk_buff *skb)
 	memcpy(cp.ltk, ltk->val, sizeof(ltk->val));
 	cp.handle = cpu_to_le16(conn->handle);
 
-	if (ltk->authenticated)
-		conn->pending_sec_level = BT_SECURITY_HIGH;
-	else
-		conn->pending_sec_level = BT_SECURITY_MEDIUM;
+	conn->pending_sec_level = smp_ltk_sec_level(ltk);
 
 	conn->enc_key_size = ltk->enc_size;
 

net/bluetooth/smp.c

@@ -1114,7 +1114,7 @@ static bool smp_ltk_encrypt(struct l2cap_conn *conn, u8 sec_level)
 	if (!key)
 		return false;
 
-	if (sec_level > BT_SECURITY_MEDIUM && !key->authenticated)
+	if (smp_ltk_sec_level(key) < sec_level)
 		return false;
 
 	if (test_and_set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->flags))

net/bluetooth/smp.h

@@ -125,6 +125,14 @@ enum {
 	SMP_LTK_SLAVE,
 };
 
+static inline u8 smp_ltk_sec_level(struct smp_ltk *key)
+{
+	if (key->authenticated)
+		return BT_SECURITY_HIGH;
+
+	return BT_SECURITY_MEDIUM;
+}
+
 /* SMP Commands */
 bool smp_sufficient_security(struct hci_conn *hcon, u8 sec_level);
 int smp_conn_security(struct hci_conn *hcon, __u8 sec_level);