Bluetooth: Add SC-only mode support for SMP

When Secure Connections-only mode is enabled we should reject any
pairing command that does not have Secure Connections set in the
authentication requirements. This patch adds the appropriate logic for
this to the command handlers of Pairing Request/Response and Security
Request.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/smp.c

@@ -1608,6 +1608,9 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 	    (auth & SMP_AUTH_BONDING))
 		return SMP_PAIRING_NOTSUPP;
 
+	if (test_bit(HCI_SC_ONLY, &hdev->dev_flags) && !(auth & SMP_AUTH_SC))
+		return SMP_AUTH_REQUIREMENTS;
+
 	smp->preq[0] = SMP_CMD_PAIRING_REQ;
 	memcpy(&smp->preq[1], req, sizeof(*req));
 	skb_pull(skb, sizeof(*req));
@@ -1752,6 +1755,9 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 
 	auth = rsp->auth_req & AUTH_REQ_MASK(hdev);
 
+	if (test_bit(HCI_SC_ONLY, &hdev->dev_flags) && !(auth & SMP_AUTH_SC))
+		return SMP_AUTH_REQUIREMENTS;
+
 	smp->prsp[0] = SMP_CMD_PAIRING_RSP;
 	memcpy(&smp->prsp[1], rsp, sizeof(*rsp));
 
@@ -2008,6 +2014,9 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
 
 	auth = rp->auth_req & AUTH_REQ_MASK(hdev);
 
+	if (test_bit(HCI_SC_ONLY, &hdev->dev_flags) && !(auth & SMP_AUTH_SC))
+		return SMP_AUTH_REQUIREMENTS;
+
 	if (hcon->io_capability == HCI_IO_NO_INPUT_OUTPUT)
 		sec_level = BT_SECURITY_MEDIUM;
 	else