1 files changed, 77 insertions, 0 deletions
diff --git a/control/keyfallback/keyfallback_test.go b/control/keyfallback/keyfallback_test.go
new file mode 100644
index 000000000..92aa6b0e6
--- /dev/null
+++ b/control/keyfallback/keyfallback_test.go
@@ -0,0 +1,77 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package keyfallback
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"reflect"
+	"testing"
+	"time"
+
+	"tailscale.com/ipn"
+	"tailscale.com/tailcfg"
+	"tailscale.com/tstest/nettest"
+	"tailscale.com/util/must"
+)
+
+func TestHasValidControlKey(t *testing.T) {
+	t.Parallel()
+	keys, err := Get()
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+	if keys.PublicKey.IsZero() {
+		t.Fatalf("zero key")
+	}
+}
+
+// TestKeyIsUpToDate fetches the control key from the control server and
+// compares it to the baked-in key, to verify that it's up-to-date. If the
+// control server is unreachable, the test is skipped.
+func TestKeyIsUpToDate(t *testing.T) {
+	nettest.SkipIfNoNetwork(t)
+
+	// Optimistically fetch the control key and check if it's up to date,
+	// but ignore if we don't have network access (e.g. running tests on an
+	// airplane).
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	keyURL := fmt.Sprintf("%v/key?v=%d", ipn.DefaultControlURL, tailcfg.CurrentCapabilityVersion)
+	req := must.Get(http.NewRequestWithContext(ctx, "GET", keyURL, nil))
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Logf("fetch control key: %v", err)
+		return
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode != 200 {
+		t.Fatalf("fetch control key: bad status; got %v, want 200", res.Status)
+	}
+	b, err := io.ReadAll(res.Body)
+	if err != nil {
+		t.Fatalf("read control key: %v", err)
+	}
+
+	// Verify that the key is up to date and matches the baked-in key.
+	out := &tailcfg.OverTLSPublicKeyResponse{}
+	if err := json.Unmarshal(b, out); err != nil {
+		t.Fatalf("unmarshal control key: %v", err)
+	}
+
+	keys, err := Get()
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+
+	if !reflect.DeepEqual(keys, out) {
+		t.Errorf("control key is out of date")
+		t.Logf("old key: %v", keys)
+		t.Logf("new key: %v", out)
+	}
+}