NVIDIA Driver – Escape 0x100010b Missing Bounds Check

• Exploit Database
• 15 阅读

• 作者： Google Security Research
  日期： 2016-10-31
• 类别：

  • dos
  平台：

  • windows
• 来源：https://www.exploit-db.com/exploits/40661/

• Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=927
  
  The DxgkDdiEscape handler for escape code 0x100010b looks like:
  
  char escape_100010b(NvMiniportDeviceContext *miniport_context, HANDLE handle, unsigned int idx)
  {
  PVOID *Object;
  if ( !handle )
  do_debug_thingo();
  Object = (PVOID *)&miniport_context->UNKNOWN[8 * idx + 22696];
  if ( !ObReferenceObjectByHandle(handle_, SYNCHRONIZE, )ExEventObjectType, UserMode, Object, 0i64) )
  {
  result = 0;
  if ( *Object )
  result = UserMode;
  }
  return result;
  }
  
  It essentially takes in a user mode event handle from userspace, and calls
  ObReferenceObjectByHandle on it, writing the object pointer to |Object|. Note
  that the kernel implementation of ObReferenceObjectByHandle always begins with
  writing NULL to this pointer regardless of whether or not the handle is valid.
  
  |Object| is calculated using a user provided index that is not bounds checked,
  leading to OOB write of either NULL or the KEVENT pointer:
  
  Object = (PVOID *)&miniport_context_->UNKNOWN[8 * idx + 22696];
  
  The attached PoC causes the following crashing context on Win x64 372.54:
  
  PAGE_FAULT_IN_NONPAGED_AREA (50)
  ...
  rax=ffffe0025ea28f50 rbx=0000000000000000 rcx=0000000000000000
  rdx=0000000000100000 rsi=0000000000000000 rdi=0000000000000000
  rip=fffff801d8f3daf5 rsp=ffffd000203deda0 rbp=0000000000000001
   r8=ffffe000506d4b50r9=ffffe000524fb201 r10=0000000000000000
  r11=ffffd000203df370 r12=0000000000000000 r13=0000000000000000
  r14=0000000000000000 r15=0000000000000000
  iopl=0 nv up ei pl zr na po nc
  nt!ObReferenceObjectByHandleWithTag+0x45:
  fffff801`d8f3daf5 488908mov qword ptr [rax],rcx ds:ffffe002`5ea28f50=????????????????
  
  To reproduce, compile as a x64 executable and run (requires WDK for D3DKMTEscape).
  
  
  Proof of Concept:
  https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/40661.zip