fix: opt-in tailscale vpn loop prevention (#148)

Co-authored-by: Dean Sheather <[email protected]>

Author: ibetitsmike

App/App.xaml.cs

@@ -92,6 +92,7 @@ public App()
 
         services.AddSingleton<IDispatcherQueueManager>(_ => this);
         services.AddSingleton<IDefaultNotificationHandler>(_ => this);
+        services.AddSingleton<ISettingsManager<CoderConnectSettings>, SettingsManager<CoderConnectSettings>>();
         services.AddSingleton<ICredentialBackend>(_ =>
             new WindowsCredentialBackend(WindowsCredentialBackend.CoderCredentialsTargetName));
         services.AddSingleton<ICredentialManager, CredentialManager>();
@@ -120,7 +121,6 @@ public App()
         // FileSyncListMainPage is created by FileSyncListWindow.
         services.AddTransient<FileSyncListWindow>();
 
-        services.AddSingleton<ISettingsManager<CoderConnectSettings>, SettingsManager<CoderConnectSettings>>();
         services.AddSingleton<IStartupManager, StartupManager>();
         // SettingsWindow views and view models
         services.AddTransient<SettingsViewModel>();

App/Models/Settings.cs

@@ -34,6 +34,11 @@ public class CoderConnectSettings : ISettings<CoderConnectSettings>
     /// </summary>
     public bool ConnectOnLaunch { get; set; }
 
+    /// <summary>
+    /// When this is true Coder Connect will not attempt to protect against Tailscale loopback issues.
+    /// </summary>
+    public bool EnableCorporateVpnSupport { get; set; }
+
     /// <summary>
     /// CoderConnect current settings version. Increment this when the settings schema changes.
     /// In future iterations we will be able to handle migrations when the user has
@@ -46,17 +51,21 @@ public CoderConnectSettings()
         Version = VERSION;
 
         ConnectOnLaunch = false;
+
+        EnableCorporateVpnSupport = false;
     }
 
-    public CoderConnectSettings(int? version, bool connectOnLaunch)
+    public CoderConnectSettings(int? version, bool connectOnLaunch, bool enableCorporateVpnSupport)
     {
         Version = version ?? VERSION;
 
         ConnectOnLaunch = connectOnLaunch;
+
+        EnableCorporateVpnSupport = enableCorporateVpnSupport;
     }
 
     public CoderConnectSettings Clone()
     {
-        return new CoderConnectSettings(Version, ConnectOnLaunch);
+        return new CoderConnectSettings(Version, ConnectOnLaunch, EnableCorporateVpnSupport);
     }
 }

App/Services/CredentialManager.cs

@@ -223,8 +223,9 @@ private async Task<CredentialModel> LoadCredentialsInner(CancellationToken ct)
             };
         }
 
-        // Grab the lock again so we can update the state.
-        using (await _opLock.LockAsync(ct))
+        // Grab the lock again so we can update the state. Don't use the CT
+        // here as it may have already been canceled.
+        using (await _opLock.LockAsync(TimeSpan.FromSeconds(5), CancellationToken.None))
         {
             // Prevent new LoadCredentials calls from returning this task.
             if (_loadCts != null)
@@ -242,11 +243,8 @@ private async Task<CredentialModel> LoadCredentialsInner(CancellationToken ct)
                 if (latestCreds is not null) return latestCreds;
             }
 
-            // If there aren't any latest credentials after a cancellation, we
-            // most likely timed out and should throw.
-            ct.ThrowIfCancellationRequested();
-
             UpdateState(model);
+            ct.ThrowIfCancellationRequested();
             return model;
         }
     }

App/Services/RpcController.cs

@@ -69,16 +69,18 @@ public interface IRpcController : IAsyncDisposable
 public class RpcController : IRpcController
 {
     private readonly ICredentialManager _credentialManager;
+    private readonly ISettingsManager<CoderConnectSettings> _settingsManager;
 
     private readonly RaiiSemaphoreSlim _operationLock = new(1, 1);
     private Speaker<ClientMessage, ServiceMessage>? _speaker;
 
     private readonly RaiiSemaphoreSlim _stateLock = new(1, 1);
     private readonly RpcModel _state = new();
 
-    public RpcController(ICredentialManager credentialManager)
+    public RpcController(ICredentialManager credentialManager, ISettingsManager<CoderConnectSettings> settingsManager)
     {
         _credentialManager = credentialManager;
+        _settingsManager = settingsManager;
     }
 
     public event EventHandler<RpcModel>? StateChanged;
@@ -156,6 +158,7 @@ public async Task StartVpn(CancellationToken ct = default)
         using var _ = await AcquireOperationLockNowAsync();
         AssertRpcConnected();
 
+        var coderConnectSettings = await _settingsManager.Read(ct);
         var credentials = _credentialManager.GetCachedCredentials();
         if (credentials.State != CredentialState.Valid)
             throw new RpcOperationException(
@@ -175,6 +178,7 @@ public async Task StartVpn(CancellationToken ct = default)
                 {
                     CoderUrl = credentials.CoderUrl?.ToString(),
                     ApiToken = credentials.ApiToken,
+                    TunnelUseSoftNetIsolation = coderConnectSettings.EnableCorporateVpnSupport,
                 },
             }, ct);
         }

App/ViewModels/SettingsViewModel.cs

@@ -13,6 +13,9 @@ public partial class SettingsViewModel : ObservableObject
     [ObservableProperty]
     public partial bool ConnectOnLaunch { get; set; }
 
+    [ObservableProperty]
+    public partial bool DisableTailscaleLoopProtection { get; set; }
+
     [ObservableProperty]
     public partial bool StartOnLoginDisabled { get; set; }
 
@@ -31,6 +34,7 @@ public SettingsViewModel(ILogger<SettingsViewModel> logger, ISettingsManager<Cod
         _connectSettings = settingsManager.Read().GetAwaiter().GetResult();
         StartOnLogin = startupManager.IsEnabled();
         ConnectOnLaunch = _connectSettings.ConnectOnLaunch;
+        DisableTailscaleLoopProtection = _connectSettings.EnableCorporateVpnSupport;
 
         // Various policies can disable the "Start on login" option.
         // We disable the option in the UI if the policy is set.
@@ -43,6 +47,21 @@ public SettingsViewModel(ILogger<SettingsViewModel> logger, ISettingsManager<Cod
         }
     }
 
+    partial void OnDisableTailscaleLoopProtectionChanged(bool oldValue, bool newValue)
+    {
+        if (oldValue == newValue)
+            return;
+        try
+        {
+            _connectSettings.EnableCorporateVpnSupport = DisableTailscaleLoopProtection;
+            _connectSettingsManager.Write(_connectSettings);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError($"Error saving Coder Connect {nameof(DisableTailscaleLoopProtection)} settings: {ex.Message}");
+        }
+    }
+
     partial void OnConnectOnLaunchChanged(bool oldValue, bool newValue)
     {
         if (oldValue == newValue)
@@ -54,7 +73,7 @@ partial void OnConnectOnLaunchChanged(bool oldValue, bool newValue)
         }
         catch (Exception ex)
         {
-            _logger.LogError($"Error saving Coder Connect settings: {ex.Message}");
+            _logger.LogError($"Error saving Coder Connect {nameof(ConnectOnLaunch)} settings: {ex.Message}");
         }
     }
 

App/Views/Pages/SettingsMainPage.xaml

@@ -44,6 +44,12 @@
                                        >
                     <ToggleSwitch IsOn="{x:Bind ViewModel.ConnectOnLaunch, Mode=TwoWay}" />
                 </controls:SettingsCard>
+                <controls:SettingsCard Description="This setting loosens some VPN loop protection checks in Coder Connect, allowing traffic to flow to a Coder deployment behind a corporate VPN. We only recommend enabling this option if Coder Connect doesn't work with your Coder deployment behind a corporate VPN."
+                       Header="Enable support for corporate VPNs"
+                       HeaderIcon="{ui:FontIcon Glyph=&#xE705;}"
+                       >
+                    <ToggleSwitch IsOn="{x:Bind ViewModel.DisableTailscaleLoopProtection, Mode=TwoWay}" />
+                </controls:SettingsCard>
             </StackPanel>
         </Grid>
     </ScrollViewer>

App/Views/SettingsWindow.xaml

@@ -9,8 +9,8 @@
     xmlns:winuiex="using:WinUIEx"
     mc:Ignorable="d"
     Title="Coder Settings"
-    Width="600" Height="350"
-    MinWidth="600" MinHeight="350">
+    Width="600" Height="500"
+    MinWidth="600" MinHeight="500">
 
     <Window.SystemBackdrop>
         <MicaBackdrop/>

App/Views/TrayWindow.xaml.cs

@@ -5,11 +5,9 @@
 using Coder.Desktop.App.Views.Pages;
 using CommunityToolkit.Mvvm.Input;
 using Microsoft.UI;
-using Microsoft.UI.Input;
 using Microsoft.UI.Windowing;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Documents;
 using Microsoft.UI.Xaml.Media.Animation;
 using System;
 using System.Collections.Generic;
@@ -19,6 +17,7 @@
 using Windows.Graphics;
 using Windows.System;
 using Windows.UI.Core;
+using Microsoft.UI.Input;
 using WinRT.Interop;
 using WindowActivatedEventArgs = Microsoft.UI.Xaml.WindowActivatedEventArgs;
 
@@ -41,7 +40,6 @@ public sealed partial class TrayWindow : Window
 
     private readonly IRpcController _rpcController;
     private readonly ICredentialManager _credentialManager;
-    private readonly ISyncSessionController _syncSessionController;
     private readonly IUpdateController _updateController;
     private readonly IUserNotifier _userNotifier;
     private readonly TrayWindowLoadingPage _loadingPage;
@@ -51,15 +49,13 @@ public sealed partial class TrayWindow : Window
 
     public TrayWindow(
         IRpcController rpcController, ICredentialManager credentialManager,
-        ISyncSessionController syncSessionController, IUpdateController updateController,
-        IUserNotifier userNotifier,
+        IUpdateController updateController, IUserNotifier userNotifier,
         TrayWindowLoadingPage loadingPage,
         TrayWindowDisconnectedPage disconnectedPage, TrayWindowLoginRequiredPage loginRequiredPage,
         TrayWindowMainPage mainPage)
     {
         _rpcController = rpcController;
         _credentialManager = credentialManager;
-        _syncSessionController = syncSessionController;
         _updateController = updateController;
         _userNotifier = userNotifier;
         _loadingPage = loadingPage;
@@ -74,9 +70,7 @@ public TrayWindow(
 
         _rpcController.StateChanged += RpcController_StateChanged;
         _credentialManager.CredentialsChanged += CredentialManager_CredentialsChanged;
-        _syncSessionController.StateChanged += SyncSessionController_StateChanged;
-        SetPageByState(_rpcController.GetState(), _credentialManager.GetCachedCredentials(),
-            _syncSessionController.GetState());
+        SetPageByState(_rpcController.GetState(), _credentialManager.GetCachedCredentials());
 
         // Setting these directly in the .xaml doesn't seem to work for whatever reason.
         TrayIcon.OpenCommand = Tray_OpenCommand;
@@ -127,8 +121,7 @@ public TrayWindow(
         };
     }
 
-    private void SetPageByState(RpcModel rpcModel, CredentialModel credentialModel,
-        SyncSessionControllerStateModel syncSessionModel)
+    private void SetPageByState(RpcModel rpcModel, CredentialModel credentialModel)
     {
         if (credentialModel.State == CredentialState.Unknown)
         {
@@ -201,18 +194,13 @@ private void MaybeNotifyUser(RpcModel rpcModel)
 
     private void RpcController_StateChanged(object? _, RpcModel model)
     {
-        SetPageByState(model, _credentialManager.GetCachedCredentials(), _syncSessionController.GetState());
+        SetPageByState(model, _credentialManager.GetCachedCredentials());
         MaybeNotifyUser(model);
     }
 
     private void CredentialManager_CredentialsChanged(object? _, CredentialModel model)
     {
-        SetPageByState(_rpcController.GetState(), model, _syncSessionController.GetState());
-    }
-
-    private void SyncSessionController_StateChanged(object? _, SyncSessionControllerStateModel model)
-    {
-        SetPageByState(_rpcController.GetState(), _credentialManager.GetCachedCredentials(), model);
+        SetPageByState(_rpcController.GetState(), model);
     }
 
     // Sadly this is necessary because Window.Content.SizeChanged doesn't

Tests.App/Services/CredentialManagerTest.cs

@@ -317,7 +317,10 @@ public async Task SetDuringLoad(CancellationToken ct)
         var loadTask = manager.LoadCredentials(ct);
         // Then fully perform a set.
         await manager.SetCredentials(TestServerUrl, TestApiToken, ct).WaitAsync(ct);
-        // The load should have been cancelled.
-        Assert.ThrowsAsync<TaskCanceledException>(() => loadTask);
+
+        // The load should complete with the new valid credentials
+        var result = await loadTask;
+        Assert.That(result.State, Is.EqualTo(CredentialState.Valid));
+        Assert.That(result.CoderUrl?.ToString(), Is.EqualTo(TestServerUrl));
     }
 }

Vpn.Proto/vpn.proto

@@ -62,7 +62,7 @@ message ServiceMessage {
 		StartResponse start = 2;
 		StopResponse stop = 3;
 		Status status = 4;                // either in reply to a StatusRequest or broadcasted
-		StartProgress start_progress = 5; // broadcasted during startup
+		StartProgress start_progress = 5; // broadcasted during startup (used exclusively by Windows)
 	}
 }
 
@@ -214,6 +214,7 @@ message NetworkSettingsResponse {
 // StartResponse.
 message StartRequest {
 	int32 tunnel_file_descriptor = 1;
+	bool tunnel_use_soft_net_isolation = 8;
 	string coder_url = 2;
 	string api_token = 3;
 	// Additional HTTP headers added to all requests