#include <assert.h>
#include <stdio.h>
#include <windows.h>
using AllocateFunctionPtr = PVOID(__stdcall *)(PVOID, ULONG, SIZE_T);
using ReAllocateFunctionPtr = PVOID(__stdcall *)(PVOID, ULONG, PVOID, SIZE_T);
using FreeFunctionPtr = PVOID(__stdcall *)(PVOID, ULONG, PVOID);
int main() {
HMODULE NtDllHandle = GetModuleHandle("ntdll.dll");
if (!NtDllHandle) {
puts("Couldn't load ntdll??");
return -1;
}
auto RtlAllocateHeap_ptr = (AllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlAllocateHeap");
if (RtlAllocateHeap_ptr == 0) {
puts("Couldn't find RtlAllocateHeap");
return -1;
}
auto RtlReAllocateHeap_ptr = (ReAllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlReAllocateHeap");
if (RtlReAllocateHeap_ptr == 0) {
puts("Couldn't find RtlReAllocateHeap");
return -1;
}
char *buffer;
SIZE_T buffer_size = 32;
SIZE_T new_buffer_size = buffer_size * 2;
buffer = (char *)RtlAllocateHeap_ptr(GetProcessHeap(), HEAP_ZERO_MEMORY, buffer_size);
assert(buffer != nullptr);
for (SIZE_T i = 0; i < buffer_size; ++i) {
assert(buffer[i] == 0);
}
memset(buffer, 0xcc, buffer_size);
buffer = (char *)RtlReAllocateHeap_ptr(GetProcessHeap(), HEAP_ZERO_MEMORY, buffer, new_buffer_size);
assert(buffer != nullptr);
for (SIZE_T i = 0; i < buffer_size; ++i) {
assert(buffer[i] == (char)0xcc);
}
for (SIZE_T i = buffer_size; i < new_buffer_size; ++i) {
assert(buffer[i] == 0x0);
}
buffer = (char *)RtlReAllocateHeap_ptr(GetProcessHeap(), HEAP_ZERO_MEMORY, buffer, buffer_size);
assert(buffer != nullptr);
for (SIZE_T i = 0; i < buffer_size; ++i) {
assert(buffer[i] == (char)0xcc);
}
buffer[buffer_size + 1] = 'a';
}