/*
 driver loader is used to install the driver via service manager 
 it also sends some commands to driver
 usage is simple: load driver_name driver_display_name path
 you can use loadhook.bat 

 second thread was added to receive events from driver 
 it uses asynchronous IO to manage this
 see description in the main driver file for more
*/

#include <windows.h>
#include <stdio.h>
#include <ddk/ntddk.h>
#include "../drvcomm.h"


int work=0;                                     //indicator of application status
HANDLE notify_event;                            //sync event between notify thread and main thread
int notify_type;                                //type of driver notification
DWORD notify_data;                              //driver notification data
HANDLE notify_dev;                              //notify thread device file

/*
 second thread manages notifications from driver
 we do not take any action if something in this thread failed
 however, for the functionality of our program this thread is important 
 so in real world program this should be handled too
 also synchronization is missing in this example
*/

DWORD WINAPI notify_thread(LPVOID args)
{
  printf("Notify thread runs\n");
  HANDLE notify_dev=CreateFile(args,GENERIC_READ | GENERIC_WRITE,FILE_SHARE_READ | FILE_SHARE_WRITE,
                               NULL,OPEN_EXISTING,FILE_FLAG_OVERLAPPED,NULL);
  if (notify_dev==INVALID_HANDLE_VALUE) notify_dev=0;
  if (notify_dev)
  {
    OVERLAPPED overlapped;
    overlapped.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);

    if (overlapped.hEvent)
    {
      while (work)
      {
        DRVCOMM_REQUEST_BUFFER buf_req;
        DRVCOMM_RESPONSE_BUFFER buf_res;
        memset(&buf_req,0,sizeof(buf_req));
        memset(&buf_res,0,sizeof(buf_res));

        DWORD bytes;
        int ret=DeviceIoControl(notify_dev,IOCTL_NOTIFY,NULL,0,&buf_res,sizeof(buf_res),&bytes,&overlapped);

        int err=ret?0:GetLastError();

        if (err==ERROR_IO_PENDING)
        {
          if (GetOverlappedResult(notify_dev,&overlapped,&bytes,TRUE)) err=0;
          else err=GetLastError();
        }

        if (err)
        {
          if (err==ERROR_OPERATION_ABORTED) printf("Notify thread received exit signal\n");
          else printf("Notify thread error: unexpected DeviceIoControl error %d\n",err);
          break;
        }

        if (!bytes || !buf_res.status)
        {
          printf("Notify thread communication error: bytes=%d; buf_res.status=0x%.8X\n",bytes,buf_res.status);
          break;
        }

        /*
         we've received notification from driver
        */

        switch (buf_res.type)
        {
          case RESPONSE_PROCESS_CHECK:
            printf("Notify thread: RESPONSE_PROCESS_CHECK received, you should make a decision:\n");
            notify_type=RESPONSE_PROCESS_CHECK;
            notify_data=buf_res.parameters.process_check.pid;

            printf("permit 0x%.8X access for process pid=%d to process pid=%d?\n",
                   buf_res.parameters.process_check.access,buf_res.parameters.process_check.caller_pid,notify_data);

            PulseEvent(notify_event);
            WaitForSingleObject(notify_event,INFINITE);
            printf("Notify thread wait done, answer = %s\n",notify_data?"deny":"permit");

            buf_req.parameters.process_check.permit=notify_data;
            ret=DeviceIoControl(notify_dev,IOCTL_NOTIFY_PROCESS_CHECK,&buf_req,sizeof(buf_req),NULL,0,&bytes,&overlapped);

            if (!ret && (GetLastError()==ERROR_IO_PENDING)) GetOverlappedResult(notify_dev,&overlapped,&bytes,TRUE);
            break;

          default:
            printf("Notify thread error: unknown response buffer type\n");
        }
      }
      CloseHandle(overlapped.hEvent);
    } else printf("Notify thread error: unable to create event\n");

    CloseHandle(notify_dev);
  } else printf("Notify thread error: unable to connect device\n");

  printf("Notify thread terminates\n");
  ExitThread(0);
}



int main(int argc,char **argv)
{
  /*
   this version uses ZwQueryInformationThread in kernel driver to determine
   process that owns specific thread, unfortunately ntoskrnl.exe exports 
   ZwQueryInformationThread in XP and higher, but the implementation is also 
   available in W2k, so we will do a little hack here and from user mode 
   ntdll.dll we retrieve an index to SDT and send it to kernel driver to call
   ZwQueryInformationThread using this index
   we could hardcode the index for W2k but this way it is more elegant as we 
   don't need to care about service pack differences
   this is quite simple solution but it works only if this function is not 
   hooked in ntdll.dll, if the function is hooked (and index is rewritten)
   this hack fails, however, in this case we should load and map ntdll.dll
   from disk to get raw unhooked image and find our function address in export 
   table and retrieve the index from the image then, this is not implemented 
   in this version, we assume clear (not hooked) environment
  */
  ULONG SDT_index_ZwQIT=0;
  HMODULE ntdll=GetModuleHandle("ntdll.dll");
  PVOID ZwQIT=GetProcAddress(ntdll,"ZwQueryInformationThread");
  if (ZwQIT) SDT_index_ZwQIT=*((PULONG)((UCHAR *)ZwQIT+1));

  printf("SDT_index_ZwQIT = 0x%.8X\n",SDT_index_ZwQIT);
  if (SDT_index_ZwQIT>0x0200) SDT_index_ZwQIT=0;
  if (!SDT_index_ZwQIT)
  {
    printf("error: unable to retrieve valid SDT index for ZwQueryInformationThread\n");
    return 0;
  }

  printf("Opening service manager ...\n");
  HANDLE scm=OpenSCManager(NULL,NULL,SC_MANAGER_CREATE_SERVICE);
  
  if(scm)
  {
    printf("Creating service ...\n");

    HANDLE svc=CreateService(scm,argv[1],argv[2],SERVICE_START | DELETE | SERVICE_STOP,SERVICE_KERNEL_DRIVER,
                             SERVICE_DEMAND_START,SERVICE_ERROR_IGNORE,argv[3],NULL,NULL,NULL,NULL,NULL);

    if(!svc)
    {
      printf("Creating failed, trying to open service ...\n");
      svc=OpenService(scm,argv[1],SERVICE_START | DELETE | SERVICE_STOP);
    }

    if(svc)
    {
      printf("Starting service\n");

      StartService(svc,0,NULL);

      printf("Creating communication device ...\n");

      /*
       for MSTS we need to use Global namespace to access our device
      */
      char dev_name[256];
      if ((GetVersion()&0xFF)>=5) sprintf(dev_name,"\\\\.\\Global\\%s\0",argv[1]);
      else sprintf(dev_name,"\\\\.\\%s\0",argv[1]);

      HANDLE dev=CreateFile(dev_name,GENERIC_READ | GENERIC_WRITE,FILE_SHARE_READ | FILE_SHARE_WRITE,NULL,OPEN_EXISTING,0,NULL);

      if (dev==INVALID_HANDLE_VALUE) dev=0;
      if (dev)
      {
        printf("Starting notify thread\n");
        work=1;
        DWORD tid;
        HANDLE thread=CreateThread(NULL,0,notify_thread,dev_name,0,&tid);
        if (thread==INVALID_HANDLE_VALUE) thread=0;
        notify_event=CreateEvent(NULL,TRUE,FALSE,NULL);

        if (thread && notify_event)
        {
          CloseHandle(thread);

          printf("Press Enter to send IOCTL_HOOK_START\n");
          getchar();

          DRVCOMM_REQUEST_BUFFER buf_req;
          DRVCOMM_RESPONSE_BUFFER buf_res;
          DWORD bytes=0,ret;

          buf_req.parameters.init.SDT_index_ZwQueryInformationThread=SDT_index_ZwQIT;

          /*
           send command to our driver, no input buffer is used here
           output buffer contains status value only
          */
          memset(&buf_res,0,sizeof(buf_res));
          ret=DeviceIoControl(dev,IOCTL_HOOK_START,&buf_req,sizeof(buf_req),&buf_res,sizeof(buf_res),&bytes,NULL);
          printf("DeviceIoControl returned code 0x%.8X, status 0x%.8X and %d bytes\n",ret,buf_res.status,bytes);

          if (buf_res.status)
          {
            /*
             this is a loop for driver rules managment
            */
            printf("\nenter commands to protect/disable protection of processes\n"
                   "to enable protection for process write 'e PID'\n"
                   "to disable protection for process write 'd PID'\n"
                   "to answer process check write 'p 0/1' - '0' for deny and '1' for permit\n"
                   "current process id = %d\n"
                   "write 'x 0' for end\n",GetCurrentProcessId());

            while (work)
            {
              bytes=0;
              char ch_type;
              int obj_id=0;
              scanf("%c %d",&ch_type,&obj_id);
              getchar();

              int enable;
              ULONG code;

              switch (ch_type)
              {
                case 'd':
                case 'e':
                  enable=ch_type=='e';
                  code=IOCTL_PROTECT_PROCESS;
                  buf_req.parameters.protect_process.pid=obj_id;
                  buf_req.parameters.protect_process.enable=enable;
                  ret=DeviceIoControl(dev,code,&buf_req,sizeof(buf_req),&buf_res,sizeof(buf_res),&bytes,NULL);
                  printf("DeviceIoControl returned code 0x%.8X, status 0x%.8X and %d bytes\n",ret,buf_res.status,bytes);
                  break;

                case 'p':
                  notify_data=!obj_id;          //we set protect TRUE or FALSE -> protect = !permit
                  PulseEvent(notify_event);
                  break;

                case 'x':
                  work=0;
                  break;

                default:
                  printf("unknown command type %c\n",ch_type);
              }
            }

            bytes=0;
            printf("Press Enter to send IOCTL_HOOK_STOP\n");
            getchar();

            ret=DeviceIoControl(dev,IOCTL_HOOK_STOP,NULL,0,&buf_res,sizeof(buf_res),&bytes,NULL);
            printf("DeviceIoControl returned code 0x%.8X, status 0x%.8X and %d bytes\n",ret,buf_res.status,bytes);

            //cancel possible waiting
            PulseEvent(notify_event);
          }

          printf("Press Enter to send close device handle\n");
          getchar();
          CloseHandle(dev);
        } else printf("error: unable to create notify thread\n");

        if (notify_event) CloseHandle(notify_event);

      } else printf("error: unable to create communication device\n");

      printf("Press Enter to stop and delete service \n");
      getchar();

      SERVICE_STATUS status;
      ControlService(svc,SERVICE_CONTROL_STOP,&status);

      DeleteService(svc);
      CloseServiceHandle(svc);
    } else printf("error: unable to create/open service\n");

    CloseServiceHandle(scm);
  } else printf("error: unable to open manager\n");
  
  return 0;
}