ipn/ipnlocal: use presence of NodeID to identify logins

The profileManager was using the LoginName as a proxy to figure out if the profile
had logged in, however the LoginName is not present if the node was created with an
Auth Key that does not have an associated user.

Signed-off-by: Maisem Ali <maisem@tailscale.com>

ipn/ipnlocal/profiles.go

@@ -185,7 +185,7 @@ func init() {
 func (pm *profileManager) SetPrefs(prefsIn ipn.PrefsView) error {
 	prefs := prefsIn.AsStruct().View()
 	newPersist := prefs.Persist().AsStruct()
-	if newPersist == nil || newPersist.LoginName == "" {
+	if newPersist == nil || newPersist.NodeID == "" {
 		return pm.setPrefsLocked(prefs)
 	}
 	up := newPersist.UserProfile

ipn/ipnlocal/profiles_test.go

@@ -5,6 +5,7 @@ package ipnlocal
 
 import (
 	"fmt"
+	"strconv"
 	"testing"
 
 	"tailscale.com/ipn"
@@ -337,6 +338,7 @@ func TestProfileManagementWindows(t *testing.T) {
 				ID:        id,
 				LoginName: loginName,
 			},
+			NodeID: tailcfg.StableNodeID(strconv.Itoa(int(id))),
 		}
 		if err := pm.SetPrefs(p.View()); err != nil {
 			t.Fatal(err)

ipn/ipnlocal/state_test.go

@@ -473,6 +473,7 @@ func TestStateMachine(t *testing.T) {
 	notifies.expect(3)
 	cc.persist.LoginName = "user1"
 	cc.persist.UserProfile.LoginName = "user1"
+	cc.persist.NodeID = "node1"
 	cc.send(nil, "", true, &netmap.NetworkMap{})
 	{
 		nn := notifies.drain(3)
@@ -699,6 +700,7 @@ func TestStateMachine(t *testing.T) {
 	notifies.expect(3)
 	cc.persist.LoginName = "user2"
 	cc.persist.UserProfile.LoginName = "user2"
+	cc.persist.NodeID = "node2"
 	cc.send(nil, "", true, &netmap.NetworkMap{
 		MachineStatus: tailcfg.MachineAuthorized,
 	})
@@ -835,6 +837,7 @@ func TestStateMachine(t *testing.T) {
 	notifies.expect(3)
 	cc.persist.LoginName = "user3"
 	cc.persist.UserProfile.LoginName = "user3"
+	cc.persist.NodeID = "node3"
 	cc.send(nil, "", true, &netmap.NetworkMap{
 		MachineStatus: tailcfg.MachineAuthorized,
 	})