如何使用C#/pinvoke将输入发送到WinSta0\Winlogon桌面

Question

我正在用C#为一套技术支持工具编写一个远程控制应用程序。一切都很好，除了我无法使用SendInput到Winlogon桌面。我成功地检测到从默认到Winlogon的更改，并且我能够切换到它并捕获屏幕截图。它只是不接受SendInput函数。我知道这是可能的，因为TeamViewer做到了，而且他们的清单中没有uiAccess=true。他们似乎在使用与我相同的流程。

简而言之，我要做的是：安装服务。服务侦听连接请求。服务在用户与CreateProcessAsUser的会话中启动新进程，并且来自winlogon.exe的重复访问令牌。Viewer连接到新进程。

有人能识别出缺少什么，让新进程访问SendInput到winlogon吗？这是我用来从服务启动新进程的代码。接下来是我用来检测Winlogon桌面更改并切换到它的代码

public static bool OpenProcessAsSystem(string applicationName, out PROCESS_INFORMATION procInfo)
{
try
{
uint winlogonPid = 0;
IntPtr hUserTokenDup = IntPtr.Zero, hPToken = IntPtr.Zero, hProcess = IntPtr.Zero;
procInfo = new PROCESS_INFORMATION();
// Obtain session ID for active session.
uint dwSessionId = Kernel32.WTSGetActiveConsoleSessionId();
// Check for RDP session.  If active, use that session ID instead.
var rdpSessionID = GetRDPSession();
if (rdpSessionID > 0)
{
dwSessionId = rdpSessionID;
}
// Obtain the process ID of the winlogon process that is running within the currently active session.
Process[] processes = Process.GetProcessesByName("winlogon");
foreach (Process p in processes)
{
if ((uint)p.SessionId == dwSessionId)
{
winlogonPid = (uint)p.Id;
}
}
// Obtain a handle to the winlogon process.
hProcess = Kernel32.OpenProcess(MAXIMUM_ALLOWED, false, winlogonPid);
// Obtain a handle to the access token of the winlogon process.
if (!OpenProcessToken(hProcess, TOKEN_DUPLICATE, ref hPToken))
{
Kernel32.CloseHandle(hProcess);
return false;
}
// Security attibute structure used in DuplicateTokenEx and CreateProcessAsUser.
SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES();
sa.Length = Marshal.SizeOf(sa);
// Copy the access token of the winlogon process; the newly created token will be a primary token.
if (!DuplicateTokenEx(hPToken, MAXIMUM_ALLOWED, ref sa, (int)SECURITY_IMPERSONATION_LEVEL.SecurityIdentification, (int)TOKEN_TYPE.TokenPrimary, ref hUserTokenDup))
{
Kernel32.CloseHandle(hProcess);
Kernel32.CloseHandle(hPToken);
return false;
}
// By default, CreateProcessAsUser creates a process on a non-interactive window station, meaning
// the window station has a desktop that is invisible and the process is incapable of receiving
// user input. To remedy this we set the lpDesktop parameter to indicate we want to enable user 
// interaction with the new process.
STARTUPINFO si = new STARTUPINFO();
si.cb = (int)Marshal.SizeOf(si);
si.lpDesktop = @"winsta0default"; // interactive window station parameter; basically this indicates that the process created can display a GUI on the desktop
// flags that specify the priority and creation method of the process
uint dwCreationFlags = NORMAL_PRIORITY_CLASS | CREATE_NEW_CONSOLE;
// create a new process in the current user's logon session
bool result = CreateProcessAsUser(hUserTokenDup,        // client's access token
null,                   // file to execute
applicationName,        // command line
ref sa,                 // pointer to process SECURITY_ATTRIBUTES
ref sa,                 // pointer to thread SECURITY_ATTRIBUTES
false,                  // handles are not inheritable
dwCreationFlags,        // creation flags
IntPtr.Zero,            // pointer to new environment block 
null,                   // name of current directory 
ref si,                 // pointer to STARTUPINFO structure
out procInfo            // receives information about new process
);
// invalidate the handles
Kernel32.CloseHandle(hProcess);
Kernel32.CloseHandle(hPToken);
Kernel32.CloseHandle(hUserTokenDup);
return result;
}
catch
{
procInfo = new PROCESS_INFORMATION() { };
return false;
}
}
public static uint GetRDPSession()
{
IntPtr ppSessionInfo = IntPtr.Zero;
Int32 count = 0;
Int32 retval = WTSAPI32.WTSEnumerateSessions(WTSAPI32.WTS_CURRENT_SERVER_HANDLE, 0, 1, ref ppSessionInfo, ref count);
Int32 dataSize = Marshal.SizeOf(typeof(WTSAPI32.WTS_SESSION_INFO));
var sessList = new List<WTSAPI32.WTS_SESSION_INFO>();
Int64 current = (int)ppSessionInfo;
if (retval != 0)
{
for (int i = 0; i < count; i++)
{
WTSAPI32.WTS_SESSION_INFO sessInf = (WTSAPI32.WTS_SESSION_INFO)Marshal.PtrToStructure((System.IntPtr)current, typeof(WTSAPI32.WTS_SESSION_INFO));
current += dataSize;
sessList.Add(sessInf);
}
}
uint retVal = 0;
var rdpSession = sessList.Find(ses => ses.pWinStationName.ToLower().Contains("rdp") && ses.State == 0);
if (sessList.Exists(ses => ses.pWinStationName.ToLower().Contains("rdp") && ses.State == 0))
{
retVal = (uint)rdpSession.SessionID;
}
return retVal;
}

以下是我用来捕捉屏幕、检测桌面变化并切换到它的内容

var hWnd = User32.GetDesktopWindow();
var hDC = User32.GetWindowDC(hWnd);
var graphDC = graphic.GetHdc();
var copyResult = GDI32.BitBlt(graphDC, 0, 0, totalWidth, totalHeight, hDC, 0, 0, GDI32.TernaryRasterOperations.SRCCOPY | GDI32.TernaryRasterOperations.CAPTUREBLT);
// Change to input desktop if copy fails.
if (!copyResult)
{
var inputDesktop = User32.OpenInputDesktop();
if (User32.SetThreadDesktop(inputDesktop) == false)
{
graphic.Clear(System.Drawing.Color.White);
var font = new Font(FontFamily.GenericSansSerif, 30, System.Drawing.FontStyle.Bold);
graphic.DrawString("Waiting for screen capture...", font, Brushes.Black, new PointF((totalWidth / 2), totalHeight / 2), new StringFormat() { Alignment = StringAlignment.Center });
var error = Marshal.GetLastWin32Error();
writeToErrorLog(new Exception("Failed to open input desktop.  Error: " + error.ToString()));
}
var dw = User32.GetDesktopWindow();
User32.SetActiveWindow(dw);
User32.SetForegroundWindow(dw);
User32.CloseDesktop(inputDesktop);
}
graphic.ReleaseHdc(graphDC);
User32.ReleaseDC(hWnd, hDC);

Answer 1

我让SendInput在登录桌面上工作(事实证明，还有UAC安全桌面)。SetThreadDesktop不能为您提供与您最初在目标桌面中启动进程相同的权限。

因此，当我检测到桌面更改时，我没有调用SetThreadDesktop，而是使用CreateProcessAsUser在新桌面中启动了另一个进程。然后我示意观众切换并关闭当前进程。

编辑(几年后)：我最终错了。您只需要确保当前线程在当前桌面上没有任何打开的窗口或挂钩。由于这只为调用线程(而不是进程)设置桌面，其他线程也需要调用它。