From cef0a474f8fb1a09e4ce3191ff000fcc21858284 Mon Sep 17 00:00:00 2001
From: Mihai Parparita <mihai@tailscale.com>
Date: Mon, 10 Apr 2023 16:41:01 -0700
Subject: [PATCH] ipn/ipnlocal: check that sockstatLogger is available in c2n
 endpoint

Otherwise there may be a panic if it's nil (and the control side of
the c2n call will just time out).

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
---
 ipn/ipnlocal/c2n.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/ipn/ipnlocal/c2n.go b/ipn/ipnlocal/c2n.go
index 85c95dad2..68c1e7e72 100644
--- a/ipn/ipnlocal/c2n.go
+++ b/ipn/ipnlocal/c2n.go
@@ -89,6 +89,10 @@ func (b *LocalBackend) handleC2N(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		w.Header().Set("Content-Type", "text/plain")
+		if b.sockstatLogger == nil {
+			http.Error(w, "no sockstatLogger", http.StatusInternalServerError)
+			return
+		}
 		b.sockstatLogger.Flush()
 		fmt.Fprintln(w, b.sockstatLogger.LogID())
 	default: