Protect against expiry nil

api.go

@@ -144,6 +144,7 @@ func (h *Headscale) RegistrationHandler(ctx *gin.Context) {
 			Name:       req.Hostinfo.Hostname,
 			NodeKey:    NodePublicKeyStripPrefix(req.NodeKey),
 			LastSeen:   &now,
+			Expiry:     &time.Time{},
 		}
 
 		if !req.Expiry.IsZero() {

machine.go

@@ -117,7 +117,7 @@ func (machine Machine) isExpired() bool {
 	// If Expiry is not set, the client has not indicated that
 	// it wants an expiry time, it is therefor considered
 	// to mean "not expired"
-	if machine.Expiry.IsZero() {
+	if machine.Expiry == nil || machine.Expiry.IsZero() {
 		return false
 	}