Bluetooth: Mesh: fix provisionee public key usage

Provisionee shall fail if provisioner sent public key
identicall to OOB public key back.

Signed-off-by: Aleksandr Khromykh <[email protected]>

Author: alxelax

subsys/bluetooth/mesh/prov_device.c

@@ -357,6 +357,13 @@ static void prov_pub_key(const uint8_t *data)
 			return;
 		}
 
+		if (!memcmp(bt_mesh_prov->public_key_be,
+			    bt_mesh_prov_link.conf_inputs.pub_key_provisioner, PDU_LEN_PUB_KEY)) {
+			LOG_ERR("Public keys are identical");
+			prov_fail(PROV_ERR_NVAL_FMT);
+			return;
+		}
+
 		/* No swap needed since user provides public key in big-endian */
 		memcpy(bt_mesh_prov_link.conf_inputs.pub_key_device, bt_mesh_prov->public_key_be,
 		       PDU_LEN_PUB_KEY);