Prompt for elevation (#457)

* Prompt for elevation

* Add error messages for interop errors

* Assume process is elevated on Windows XP

Co-authored-by: Oleg Nenashev <o.v.nenashev@gmail.com>

README.md

@@ -49,6 +49,8 @@ Your renamed *WinSW.exe* binary also accepts the following commands:
     * `Started` to indicate the service is currently running
     * `Stopped` to indicate that the service is installed but not currently running.
 
+Most commands require Administrator privileges to execute. Since v2.8, WinSW will prompt for UAC in non-elevated sessions.
+
 ## Documentation
 
 User documentation:

src/Core/ServiceWrapper/Main.cs

@@ -1,11 +1,13 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Security.AccessControl;
+using System.Security.Principal;
 using System.ServiceProcess;
 using System.Text;
 using System.Text.RegularExpressions;
@@ -589,6 +591,26 @@ namespace winsw
                 args = args.GetRange(2, args.Count - 2);
             }
 
+            bool elevated;
+            if (args[0] == "/elevated")
+            {
+                elevated = true;
+
+                _ = SigIntHelper.FreeConsole();
+                _ = SigIntHelper.AttachConsole(SigIntHelper.ATTACH_PARENT_PROCESS);
+
+                args = args.GetRange(1, args.Count - 1);
+            }
+            else if (Environment.OSVersion.Version.Major == 5)
+            {
+                // Windows XP
+                elevated = true;
+            }
+            else
+            {
+                elevated = IsProcessElevated();
+            }
+
             switch (args[0].ToLower())
             {
                 case "install":
@@ -647,6 +669,12 @@ namespace winsw
 
             void Install()
             {
+                if (!elevated)
+                {
+                    Elevate();
+                    return;
+                }
+
                 Log.Info("Installing the service with id '" + descriptor.Id + "'");
 
                 // Check if the service exists
@@ -738,6 +766,12 @@ namespace winsw
 
             void Uninstall()
             {
+                if (!elevated)
+                {
+                    Elevate();
+                    return;
+                }
+
                 Log.Info("Uninstalling the service with id '" + descriptor.Id + "'");
                 if (s is null)
                 {
@@ -777,6 +811,12 @@ namespace winsw
 
             void Start()
             {
+                if (!elevated)
+                {
+                    Elevate();
+                    return;
+                }
+
                 Log.Info("Starting the service with id '" + descriptor.Id + "'");
                 if (s is null)
                     ThrowNoSuchService();
@@ -800,6 +840,12 @@ namespace winsw
 
             void Stop()
             {
+                if (!elevated)
+                {
+                    Elevate();
+                    return;
+                }
+
                 Log.Info("Stopping the service with id '" + descriptor.Id + "'");
                 if (s is null)
                     ThrowNoSuchService();
@@ -823,6 +869,12 @@ namespace winsw
 
             void Restart()
             {
+                if (!elevated)
+                {
+                    Elevate();
+                    return;
+                }
+
                 Log.Info("Restarting the service with id '" + descriptor.Id + "'");
                 if (s is null)
                     ThrowNoSuchService();
@@ -841,6 +893,11 @@ namespace winsw
 
             void RestartSelf()
             {
+                if (!elevated)
+                {
+                    throw new UnauthorizedAccessException("Access is denied.");
+                }
+
                 Log.Info("Restarting the service with id '" + descriptor.Id + "'");
 
                 // run restart from another process group. see README.md for why this is useful.
@@ -865,6 +922,12 @@ namespace winsw
 
             void Test()
             {
+                if (!elevated)
+                {
+                    Elevate();
+                    return;
+                }
+
                 WrapperService wsvc = new WrapperService(descriptor);
                 wsvc.OnStart(args.ToArray());
                 Thread.Sleep(1000);
@@ -873,12 +936,52 @@ namespace winsw
 
             void TestWait()
             {
+                if (!elevated)
+                {
+                    Elevate();
+                    return;
+                }
+
                 WrapperService wsvc = new WrapperService(descriptor);
                 wsvc.OnStart(args.ToArray());
                 Console.WriteLine("Press any key to stop the service...");
                 Console.Read();
                 wsvc.OnStop();
             }
+
+            // [DoesNotReturn]
+            void Elevate()
+            {
+                using Process current = Process.GetCurrentProcess();
+
+                ProcessStartInfo startInfo = new ProcessStartInfo
+                {
+                    UseShellExecute = true,
+                    Verb = "runas",
+                    FileName = current.MainModule.FileName,
+#if NETCOREAPP
+                    Arguments = "/elevated " + string.Join(' ', args),
+#elif !NET20
+                    Arguments = "/elevated " + string.Join(" ", args),
+#else
+                    Arguments = "/elevated " + string.Join(" ", args.ToArray()),
+#endif
+                    WindowStyle = ProcessWindowStyle.Hidden,
+                };
+
+                try
+                {
+                    using Process elevated = Process.Start(startInfo);
+
+                    elevated.WaitForExit();
+                    Environment.Exit(elevated.ExitCode);
+                }
+                catch (Win32Exception e) when (e.NativeErrorCode == Errors.ERROR_CANCELLED)
+                {
+                    Log.Fatal(e.Message);
+                    Environment.Exit(e.ErrorCode);
+                }
+            }
         }
 
         private static void InitLoggers(ServiceDescriptor d, bool enableCLILogging)
@@ -941,6 +1044,40 @@ namespace winsw
                 appenders.ToArray());
         }
 
+        private static unsafe bool IsProcessElevated()
+        {
+            IntPtr process = Kernel32.GetCurrentProcess();
+            if (!Advapi32.OpenProcessToken(process, TokenAccessLevels.Read, out IntPtr token))
+            {
+                ThrowWin32Exception("Failed to open process token.");
+            }
+
+            try
+            {
+                if (!Advapi32.GetTokenInformation(
+                    token,
+                    TOKEN_INFORMATION_CLASS.TokenElevation,
+                    out TOKEN_ELEVATION elevation,
+                    sizeof(TOKEN_ELEVATION),
+                    out _))
+                {
+                    ThrowWin32Exception("Failed to get token information");
+                }
+
+                return elevation.TokenIsElevated != 0;
+            }
+            finally
+            {
+                _ = Kernel32.CloseHandle(token);
+            }
+
+            static void ThrowWin32Exception(string message)
+            {
+                Win32Exception inner = new Win32Exception();
+                throw new Win32Exception(inner.NativeErrorCode, message + ' ' + inner.Message);
+            }
+        }
+
         private static string ReadPassword()
         {
             StringBuilder buf = new StringBuilder();

src/Core/ServiceWrapper/winsw.csproj

@@ -5,6 +5,7 @@
     <TargetFrameworks>net20;net40;net461;netcoreapp3.1</TargetFrameworks>
     <LangVersion>latest</LangVersion>
     <Nullable>enable</Nullable>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
 
     <AssemblyTitle>Windows Service Wrapper</AssemblyTitle>
     <Description>Allows arbitrary process to run as a Windows service by wrapping it.</Description>

src/Core/WinSWCore/Native/Advapi32.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.ComponentModel;
 using System.Runtime.InteropServices;
 using System.Security.AccessControl;
+using System.Security.Principal;
 using System.Text;
 
 // ReSharper disable InconsistentNaming
@@ -321,6 +322,20 @@ namespace winsw.Native
 
         [DllImport(Advapi32LibraryName, SetLastError = false)]
         internal static extern uint LsaNtStatusToWinError(uint status);
+
+        [DllImport(Advapi32LibraryName, SetLastError = true)]
+        public static extern bool OpenProcessToken(
+            IntPtr ProcessHandle,
+            TokenAccessLevels DesiredAccess,
+            out IntPtr TokenHandle);
+
+        [DllImport(Advapi32LibraryName, SetLastError = true)]
+        public static extern bool GetTokenInformation(
+          IntPtr TokenHandle,
+          TOKEN_INFORMATION_CLASS TokenInformationClass,
+          out TOKEN_ELEVATION TokenInformation,
+          int TokenInformationLength,
+          out int ReturnLength);
     }
 
     // http://msdn.microsoft.com/en-us/library/windows/desktop/bb545671(v=vs.85).aspx
@@ -603,4 +618,14 @@ namespace winsw.Native
     {
         public string lpDescription;
     }
+
+    public enum TOKEN_INFORMATION_CLASS
+    {
+        TokenElevation = 20,
+    }
+
+    public struct TOKEN_ELEVATION
+    {
+        public uint TokenIsElevated;
+    }
 }

src/Core/WinSWCore/Native/Errors.cs

@@ -0,0 +1,7 @@
+namespace winsw.Native
+{
+    public static class Errors
+    {
+        public const int ERROR_CANCELLED = 1223;
+    }
+}

src/Core/WinSWCore/Native/Kernel32.cs

@@ -28,6 +28,12 @@ namespace winsw.Native
             string? lpCurrentDirectory,
             in STARTUPINFO lpStartupInfo,
             out PROCESS_INFORMATION lpProcessInformation);
+
+        [DllImport(Kernel32LibraryName)]
+        public static extern IntPtr GetCurrentProcess();
+
+        [DllImport(Kernel32LibraryName)]
+        public static extern bool CloseHandle(IntPtr hObject);
     }
 
     [StructLayout(LayoutKind.Sequential)]

src/Core/WinSWCore/Util/SigIntHelper.cs

@@ -9,13 +9,15 @@ namespace winsw.Util
     {
         private static readonly ILog Logger = LogManager.GetLogger(typeof(SigIntHelper));
 
+        public const int ATTACH_PARENT_PROCESS = -1;
+
         private const string Kernel32LibraryName = "kernel32.dll";
 
         [DllImport(Kernel32LibraryName, SetLastError = true)]
-        private static extern bool AttachConsole(uint dwProcessId);
+        public static extern bool AttachConsole(int dwProcessId);
 
         [DllImport(Kernel32LibraryName, SetLastError = true)]
-        private static extern bool FreeConsole();
+        public static extern bool FreeConsole();
 
         [DllImport(Kernel32LibraryName)]
         private static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate? HandlerRoutine, bool Add);
@@ -44,7 +46,7 @@ namespace winsw.Util
         /// <returns>True if the process shut down successfully to the SIGINT, false if it did not.</returns>
         public static bool SendSIGINTToProcess(Process process, TimeSpan shutdownTimeout)
         {
-            if (AttachConsole((uint)process.Id))
+            if (AttachConsole(process.Id))
             {
                 // Disable Ctrl-C handling for our program
                 _ = SetConsoleCtrlHandler(null, true);