Fix: RDP Consent-Dialog via WTSQueryUserToken+CreateProcessAsUser (v2.4.0)

- SessionSpawner.cs: Neuer Helper — WTSQueryUserToken + CreateProcessAsUser
  ersetzt fragilen schtasks-Ansatz für UI-Spawn aus SYSTEM-Service
- RtcService: SpawnConsentHelper + SpawnCaptureHelper nutzen jetzt SessionSpawner
- Findet aktive Console-Session automatisch, Fallback auf alle Sessions
- Version: 2.3.0 → 2.4.0

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

agent-cs/Services/SessionSpawner.cs

@@ -0,0 +1,160 @@
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+
+namespace ITNexusAgent.Services;
+
+// Startet Prozesse in der aktiven User-Session (aus SYSTEM-Service heraus)
+// Korrekte Win32-Methode: WTSQueryUserToken + CreateProcessAsUser
+public static class SessionSpawner
+{
+    #region Win32 P/Invoke
+
+    [DllImport("kernel32.dll")] static extern uint WTSGetActiveConsoleSessionId();
+
+    [DllImport("Wtsapi32.dll", SetLastError = true)]
+    static extern bool WTSQueryUserToken(uint sessionId, out IntPtr phToken);
+
+    [DllImport("Wtsapi32.dll", SetLastError = true)]
+    static extern bool WTSEnumerateSessions(IntPtr hServer, uint reserved, uint version,
+        out IntPtr ppSessionInfo, out uint pCount);
+
+    [DllImport("Wtsapi32.dll")] static extern void WTSFreeMemory(IntPtr pMemory);
+
+    [DllImport("advapi32.dll", SetLastError = true)]
+    static extern bool DuplicateTokenEx(IntPtr hExistingToken, uint dwDesiredAccess,
+        IntPtr lpTokenAttributes, int impersonationLevel, int tokenType, out IntPtr phNewToken);
+
+    [DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
+    static extern bool CreateProcessAsUser(IntPtr hToken, string? lpApplicationName,
+        string lpCommandLine, IntPtr lpProcessAttributes, IntPtr lpThreadAttributes,
+        bool bInheritHandles, uint dwCreationFlags, IntPtr lpEnvironment,
+        string? lpCurrentDirectory, ref STARTUPINFO lpStartupInfo,
+        out PROCESS_INFORMATION lpProcessInformation);
+
+    [DllImport("userenv.dll", SetLastError = true)]
+    static extern bool CreateEnvironmentBlock(out IntPtr lpEnvironment, IntPtr hToken, bool bInherit);
+
+    [DllImport("userenv.dll", SetLastError = true)]
+    static extern bool DestroyEnvironmentBlock(IntPtr lpEnvironment);
+
+    [DllImport("kernel32.dll", SetLastError = true)]
+    static extern bool CloseHandle(IntPtr hObject);
+
+    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+    struct STARTUPINFO
+    {
+        public int cb; public string? lpReserved; public string? lpDesktop; public string? lpTitle;
+        public uint dwX, dwY, dwXSize, dwYSize, dwXCountChars, dwYCountChars, dwFillAttribute, dwFlags;
+        public ushort wShowWindow, cbReserved2; public IntPtr lpReserved2;
+        public IntPtr hStdInput, hStdOutput, hStdError;
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    struct PROCESS_INFORMATION
+    {
+        public IntPtr hProcess, hThread;
+        public uint dwProcessId, dwThreadId;
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    struct WTS_SESSION_INFO
+    {
+        public uint SessionId; [MarshalAs(UnmanagedType.LPStr)] public string? pWinStationName;
+        public int State; // 0=Active
+    }
+
+    #endregion
+
+    // Spawnt Prozess als eingeloggter Desktop-User. Gibt PID zurück oder -1 bei Fehler.
+    public static int SpawnInUserSession(string exePath, string args)
+    {
+        var sessionId = FindActiveUserSession();
+        if (sessionId == uint.MaxValue)
+        {
+            AgentWorker.Log("SessionSpawner: Keine aktive User-Session gefunden");
+            return -1;
+        }
+
+        if (!WTSQueryUserToken(sessionId, out var userToken))
+        {
+            AgentWorker.Log($"SessionSpawner: WTSQueryUserToken fehlgeschlagen (Session={sessionId}, Error={Marshal.GetLastWin32Error()})");
+            return -1;
+        }
+
+        try
+        {
+            if (!DuplicateTokenEx(userToken, 0x10000000u, IntPtr.Zero, 2, 1, out var dupToken))
+            {
+                AgentWorker.Log($"SessionSpawner: DuplicateTokenEx fehlgeschlagen (Error={Marshal.GetLastWin32Error()})");
+                return -1;
+            }
+
+            try
+            {
+                CreateEnvironmentBlock(out var envBlock, dupToken, false);
+
+                var si = new STARTUPINFO
+                {
+                    cb = Marshal.SizeOf<STARTUPINFO>(),
+                    lpDesktop = "winsta0\\default",
+                    dwFlags = 1,    // STARTF_USESHOWWINDOW
+                    wShowWindow = 1 // SW_SHOWNORMAL
+                };
+
+                var cmdLine = $"\"{exePath}\" {args}";
+                bool ok = CreateProcessAsUser(dupToken, null, cmdLine,
+                    IntPtr.Zero, IntPtr.Zero, false,
+                    0x0400,  // CREATE_UNICODE_ENVIRONMENT
+                    envBlock, null, ref si, out var pi);
+
+                if (envBlock != IntPtr.Zero) DestroyEnvironmentBlock(envBlock);
+
+                if (!ok)
+                {
+                    AgentWorker.Log($"SessionSpawner: CreateProcessAsUser fehlgeschlagen (Error={Marshal.GetLastWin32Error()})");
+                    return -1;
+                }
+
+                CloseHandle(pi.hThread);
+                CloseHandle(pi.hProcess);
+                AgentWorker.Log($"SessionSpawner: Prozess gestartet (PID={pi.dwProcessId}, Session={sessionId})");
+                return (int)pi.dwProcessId;
+            }
+            finally { CloseHandle(dupToken); }
+        }
+        finally { CloseHandle(userToken); }
+    }
+
+    private static uint FindActiveUserSession()
+    {
+        // Zuerst Console-Session versuchen
+        var consoleSession = WTSGetActiveConsoleSessionId();
+        if (consoleSession != uint.MaxValue && TryGetTokenForSession(consoleSession))
+            return consoleSession;
+
+        // Alle Sessions durchsuchen → erste aktive (State=0) nehmen
+        if (!WTSEnumerateSessions(IntPtr.Zero, 0, 1, out var pInfo, out var count))
+            return uint.MaxValue;
+
+        try
+        {
+            var size = Marshal.SizeOf<WTS_SESSION_INFO>();
+            for (int i = 0; i < count; i++)
+            {
+                var info = Marshal.PtrToStructure<WTS_SESSION_INFO>(IntPtr.Add(pInfo, i * size));
+                if (info.State == 0 && info.SessionId != 0) // Active, nicht Session 0
+                    return info.SessionId;
+            }
+        }
+        finally { WTSFreeMemory(pInfo); }
+
+        return uint.MaxValue;
+    }
+
+    private static bool TryGetTokenForSession(uint sessionId)
+    {
+        if (!WTSQueryUserToken(sessionId, out var tok)) return false;
+        CloseHandle(tok);
+        return true;
+    }
+}