Make RtlCreateUserThread fail if process handle is not for the current

dlls/ntdll/ntdll_misc.h

@@ -93,6 +93,8 @@ extern DWORD VIRTUAL_HandleFault(LPCVOID addr);
 extern BOOL VIRTUAL_HasMapping( LPCVOID addr );
 extern void VIRTUAL_UseLargeAddressSpace(void);
 
+extern BOOL is_current_process( HANDLE handle );
+
 /* code pages */
 extern int ntdll_umbstowcs(DWORD flags, const char* src, int srclen, WCHAR* dst, int dstlen);
 extern int ntdll_wcstoumbs(DWORD flags, const WCHAR* src, int srclen, char* dst, int dstlen,

dlls/ntdll/thread.c

@@ -216,6 +216,12 @@ NTSTATUS WINAPI RtlCreateUserThread( HANDLE process, const SECURITY_DESCRIPTOR *
     int request_pipe[2];
     NTSTATUS status;
 
+    if( ! is_current_process( process ) )
+    {
+        ERR("Unsupported on other process\n");
+        return STATUS_ACCESS_DENIED;
+    }
+
     if (pipe( request_pipe ) == -1) return STATUS_TOO_MANY_OPENED_FILES;
     fcntl( request_pipe[1], F_SETFD, 1 ); /* set close on exec flag */
     wine_server_send_fd( request_pipe[0] );

dlls/ntdll/virtual.c

@@ -1028,7 +1028,7 @@ static NTSTATUS map_image( HANDLE hmapping, int fd, char *base, DWORD total_size
  *
  * Check whether a process handle is for the current process.
  */
-static BOOL is_current_process( HANDLE handle )
+BOOL is_current_process( HANDLE handle )
 {
     BOOL ret = FALSE;