Textractor/minhook/buffer.c

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2018-08-24 11:33:01 -04:00
/*
* MinHook - The Minimalistic API Hooking Library for x64/x86
* Copyright (C) 2009-2017 Tsuda Kageyu.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <windows.h>
#include "buffer.h"
// Size of each memory block. (= page size of VirtualAlloc)
#define MEMORY_BLOCK_SIZE 0x1000
// Max range for seeking a memory block. (= 1024MB)
#define MAX_MEMORY_RANGE 0x40000000
// Memory protection flags to check the executable address.
#define PAGE_EXECUTE_FLAGS \
(PAGE_EXECUTE | PAGE_EXECUTE_READ | PAGE_EXECUTE_READWRITE | PAGE_EXECUTE_WRITECOPY)
// Memory slot.
typedef struct _MEMORY_SLOT
{
union
{
struct _MEMORY_SLOT *pNext;
UINT8 buffer[MEMORY_SLOT_SIZE];
};
} MEMORY_SLOT, *PMEMORY_SLOT;
// Memory block info. Placed at the head of each block.
typedef struct _MEMORY_BLOCK
{
struct _MEMORY_BLOCK *pNext;
PMEMORY_SLOT pFree; // First element of the free slot list.
UINT usedCount;
} MEMORY_BLOCK, *PMEMORY_BLOCK;
//-------------------------------------------------------------------------
// Global Variables:
//-------------------------------------------------------------------------
// First element of the memory block list.
PMEMORY_BLOCK g_pMemoryBlocks;
//-------------------------------------------------------------------------
VOID InitializeBuffer(VOID)
{
// Nothing to do for now.
}
//-------------------------------------------------------------------------
VOID UninitializeBuffer(VOID)
{
PMEMORY_BLOCK pBlock = g_pMemoryBlocks;
g_pMemoryBlocks = NULL;
while (pBlock)
{
PMEMORY_BLOCK pNext = pBlock->pNext;
VirtualFree(pBlock, 0, MEM_RELEASE);
pBlock = pNext;
}
}
//-------------------------------------------------------------------------
#if defined(_M_X64) || defined(__x86_64__)
static LPVOID FindPrevFreeRegion(LPVOID pAddress, LPVOID pMinAddr, DWORD dwAllocationGranularity)
{
ULONG_PTR tryAddr = (ULONG_PTR)pAddress;
// Round down to the allocation granularity.
tryAddr -= tryAddr % dwAllocationGranularity;
// Start from the previous allocation granularity multiply.
tryAddr -= dwAllocationGranularity;
while (tryAddr >= (ULONG_PTR)pMinAddr)
{
MEMORY_BASIC_INFORMATION mbi;
if (VirtualQuery((LPVOID)tryAddr, &mbi, sizeof(mbi)) == 0)
break;
if (mbi.State == MEM_FREE)
return (LPVOID)tryAddr;
if ((ULONG_PTR)mbi.AllocationBase < dwAllocationGranularity)
break;
tryAddr = (ULONG_PTR)mbi.AllocationBase - dwAllocationGranularity;
}
return NULL;
}
#endif
//-------------------------------------------------------------------------
#if defined(_M_X64) || defined(__x86_64__)
static LPVOID FindNextFreeRegion(LPVOID pAddress, LPVOID pMaxAddr, DWORD dwAllocationGranularity)
{
ULONG_PTR tryAddr = (ULONG_PTR)pAddress;
// Round down to the allocation granularity.
tryAddr -= tryAddr % dwAllocationGranularity;
// Start from the next allocation granularity multiply.
tryAddr += dwAllocationGranularity;
while (tryAddr <= (ULONG_PTR)pMaxAddr)
{
MEMORY_BASIC_INFORMATION mbi;
if (VirtualQuery((LPVOID)tryAddr, &mbi, sizeof(mbi)) == 0)
break;
if (mbi.State == MEM_FREE)
return (LPVOID)tryAddr;
tryAddr = (ULONG_PTR)mbi.BaseAddress + mbi.RegionSize;
// Round up to the next allocation granularity.
tryAddr += dwAllocationGranularity - 1;
tryAddr -= tryAddr % dwAllocationGranularity;
}
return NULL;
}
#endif
//-------------------------------------------------------------------------
static PMEMORY_BLOCK GetMemoryBlock(LPVOID pOrigin)
{
PMEMORY_BLOCK pBlock;
#if defined(_M_X64) || defined(__x86_64__)
ULONG_PTR minAddr;
ULONG_PTR maxAddr;
SYSTEM_INFO si;
GetSystemInfo(&si);
minAddr = (ULONG_PTR)si.lpMinimumApplicationAddress;
maxAddr = (ULONG_PTR)si.lpMaximumApplicationAddress;
// pOrigin ± 512MB
if ((ULONG_PTR)pOrigin > MAX_MEMORY_RANGE && minAddr < (ULONG_PTR)pOrigin - MAX_MEMORY_RANGE)
minAddr = (ULONG_PTR)pOrigin - MAX_MEMORY_RANGE;
if (maxAddr > (ULONG_PTR)pOrigin + MAX_MEMORY_RANGE)
maxAddr = (ULONG_PTR)pOrigin + MAX_MEMORY_RANGE;
// Make room for MEMORY_BLOCK_SIZE bytes.
maxAddr -= MEMORY_BLOCK_SIZE - 1;
#endif
// Look the registered blocks for a reachable one.
for (pBlock = g_pMemoryBlocks; pBlock != NULL; pBlock = pBlock->pNext)
{
#if defined(_M_X64) || defined(__x86_64__)
// Ignore the blocks too far.
if ((ULONG_PTR)pBlock < minAddr || (ULONG_PTR)pBlock >= maxAddr)
continue;
#endif
// The block has at least one unused slot.
if (pBlock->pFree != NULL)
return pBlock;
}
#if defined(_M_X64) || defined(__x86_64__)
// Alloc a new block above if not found.
{
LPVOID pAlloc = pOrigin;
while ((ULONG_PTR)pAlloc >= minAddr)
{
pAlloc = FindPrevFreeRegion(pAlloc, (LPVOID)minAddr, si.dwAllocationGranularity);
if (pAlloc == NULL)
break;
pBlock = (PMEMORY_BLOCK)VirtualAlloc(
pAlloc, MEMORY_BLOCK_SIZE, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
if (pBlock != NULL)
break;
}
}
// Alloc a new block below if not found.
if (pBlock == NULL)
{
LPVOID pAlloc = pOrigin;
while ((ULONG_PTR)pAlloc <= maxAddr)
{
pAlloc = FindNextFreeRegion(pAlloc, (LPVOID)maxAddr, si.dwAllocationGranularity);
if (pAlloc == NULL)
break;
pBlock = (PMEMORY_BLOCK)VirtualAlloc(
pAlloc, MEMORY_BLOCK_SIZE, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
if (pBlock != NULL)
break;
}
}
#else
// In x86 mode, a memory block can be placed anywhere.
pBlock = (PMEMORY_BLOCK)VirtualAlloc(
NULL, MEMORY_BLOCK_SIZE, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
#endif
if (pBlock != NULL)
{
// Build a linked list of all the slots.
PMEMORY_SLOT pSlot = (PMEMORY_SLOT)pBlock + 1;
pBlock->pFree = NULL;
pBlock->usedCount = 0;
do
{
pSlot->pNext = pBlock->pFree;
pBlock->pFree = pSlot;
pSlot++;
} while ((ULONG_PTR)pSlot - (ULONG_PTR)pBlock <= MEMORY_BLOCK_SIZE - MEMORY_SLOT_SIZE);
pBlock->pNext = g_pMemoryBlocks;
g_pMemoryBlocks = pBlock;
}
return pBlock;
}
//-------------------------------------------------------------------------
LPVOID AllocateBuffer(LPVOID pOrigin)
{
PMEMORY_SLOT pSlot;
PMEMORY_BLOCK pBlock = GetMemoryBlock(pOrigin);
if (pBlock == NULL)
return NULL;
// Remove an unused slot from the list.
pSlot = pBlock->pFree;
pBlock->pFree = pSlot->pNext;
pBlock->usedCount++;
#ifdef _DEBUG
// Fill the slot with INT3 for debugging.
memset(pSlot, 0xCC, sizeof(MEMORY_SLOT));
#endif
return pSlot;
}
//-------------------------------------------------------------------------
VOID FreeBuffer(LPVOID pBuffer)
{
PMEMORY_BLOCK pBlock = g_pMemoryBlocks;
PMEMORY_BLOCK pPrev = NULL;
ULONG_PTR pTargetBlock = ((ULONG_PTR)pBuffer / MEMORY_BLOCK_SIZE) * MEMORY_BLOCK_SIZE;
while (pBlock != NULL)
{
if ((ULONG_PTR)pBlock == pTargetBlock)
{
PMEMORY_SLOT pSlot = (PMEMORY_SLOT)pBuffer;
#ifdef _DEBUG
// Clear the released slot for debugging.
memset(pSlot, 0x00, sizeof(*pSlot));
#endif
// Restore the released slot to the list.
pSlot->pNext = pBlock->pFree;
pBlock->pFree = pSlot;
pBlock->usedCount--;
// Free if unused.
if (pBlock->usedCount == 0)
{
if (pPrev)
pPrev->pNext = pBlock->pNext;
else
g_pMemoryBlocks = pBlock->pNext;
VirtualFree(pBlock, 0, MEM_RELEASE);
}
break;
}
pPrev = pBlock;
pBlock = pBlock->pNext;
}
}
//-------------------------------------------------------------------------
BOOL IsExecutableAddress(LPVOID pAddress)
{
MEMORY_BASIC_INFORMATION mi;
VirtualQuery(pAddress, &mi, sizeof(mi));
return (mi.State == MEM_COMMIT && (mi.Protect & PAGE_EXECUTE_FLAGS));
}