From 1eafe960b85eac57e1ad4331b15499a97b2f3adb Mon Sep 17 00:00:00 2001
From: Aofei Sheng <aofei@aofeisheng.com>
Date: Sat, 19 Mar 2022 01:18:20 +0800
Subject: [PATCH] fix: possible panic in
 `Headscale.scheduledDERPMapUpdateWorker`

There is a possible nil pointer dereference panic in the
`Headscale.scheduledDERPMapUpdateWorker`. Such as when the embedded
DERP server is disabled.
---
 derp.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/derp.go b/derp.go
index 7a9b2367..7abce683 100644
--- a/derp.go
+++ b/derp.go
@@ -148,7 +148,9 @@ func (h *Headscale) scheduledDERPMapUpdateWorker(cancelChan <-chan struct{}) {
 		case <-ticker.C:
 			log.Info().Msg("Fetching DERPMap updates")
 			h.DERPMap = GetDERPMap(h.cfg.DERP)
-			h.DERPMap.Regions[h.DERPServer.region.RegionID] = &h.DERPServer.region
+			if h.cfg.DERP.ServerEnabled {
+				h.DERPMap.Regions[h.DERPServer.region.RegionID] = &h.DERPServer.region
+			}
 
 			namespaces, err := h.ListNamespaces()
 			if err != nil {