uint disasmnext(unsigned char* data, uint base, uint size, uint ip, int n)
{
int i;
uint cmdsize;
unsigned char* pdata;
// Reset Disasm Structure
Capstone cp;
if(data == NULL)
return 0;
if(ip >= size)
ip = size - 1;
if(n <= 0)
return ip;
pdata = data + ip;
size -= ip;
for(i = 0; i < n && size > 0; i++)
{
if(!cp.Disassemble(0, pdata, (int)size))
cmdsize = 1;
else
cmdsize = cp.Size();
pdata += cmdsize;
ip += cmdsize;
size -= cmdsize;
}
return ip;
}
int disasmgetsize(uint addr, unsigned char* data)
{
Capstone cp;
if(!cp.Disassemble(addr, data, MAX_DISASM_BUFFER))
return 1;
return cp.Size();
}
static void HandleCapstoneOperand(Capstone & cp, int opindex, DISASM_ARG* arg)
{
const cs_x86 & x86 = cp.x86();
const cs_x86_op & op = x86.operands[opindex];
arg->segment = SEG_DEFAULT;
strcpy_s(arg->mnemonic, cp.OperandText(opindex).c_str());
switch(op.type)
{
case X86_OP_REG:
{
const char* regname = cp.RegName((x86_reg)op.reg);
arg->type = arg_normal;
uint value;
if(!valfromstring(regname, &value, true, true))
value = 0;
arg->constant = arg->value = value;
}
break;
case X86_OP_IMM:
{
arg->type = arg_normal;
arg->constant = arg->value = (duint)op.imm;
}
break;
case X86_OP_MEM:
{
arg->type = arg_memory;
const x86_op_mem & mem = op.mem;
if(mem.base == X86_REG_RIP) //rip-relative
arg->constant = cp.Address() + (duint)mem.disp + cp.Size();
else
arg->constant = (duint)mem.disp;
uint value;
if(!valfromstring(arg->mnemonic, &value, true, true))
return;
arg->value = value;
if(DbgMemIsValidReadPtr(value))
{
switch(op.size)
{
case 1:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 1);
break;
case 2:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 2);
break;
case 4:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 4);
break;
case 8:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 8);
break;
}
}
}
break;
}
}
uint disasmback(unsigned char* data, uint base, uint size, uint ip, int n)
{
int i;
uint abuf[131], addr, back, cmdsize;
unsigned char* pdata;
// Reset Disasm Structure
Capstone cp;
// Check if the pointer is not null
if(data == NULL)
return 0;
// Round the number of back instructions to 127
if(n < 0)
n = 0;
else if(n > 127)
n = 127;
// Check if the instruction pointer ip is not outside the memory range
if(ip >= size)
ip = size - 1;
// Obvious answer
if(n == 0)
return ip;
if(ip < (uint)n)
return ip;
back = MAX_DISASM_BUFFER * (n + 3); // Instruction length limited to 16
if(ip < back)
back = ip;
addr = ip - back;
pdata = data + addr;
for(i = 0; addr < ip; i++)
{
abuf[i % 128] = addr;
if(!cp.Disassemble(0, pdata, (int)size))
cmdsize = 1;
else
cmdsize = cp.Size();
pdata += cmdsize;
addr += cmdsize;
back -= cmdsize;
size -= cmdsize;
}
if(i < n)
return abuf[0];
else
return abuf[(i - n + 128) % 128];
}
int RefFindInRange(duint scanStart, duint scanSize, CBREF Callback, void* UserData, bool Silent, REFINFO & refInfo, Capstone & cp, bool initCallBack, CBPROGRESS cbUpdateProgress)
{
// Allocate and read a buffer from the remote process
Memory<unsigned char*> data(scanSize, "reffind:data");
if(!MemRead(scanStart, data(), scanSize))
{
if(!Silent)
dprintf("Error reading memory in reference search\n");
return 0;
}
if(initCallBack)
Callback(0, 0, &refInfo);
//concurrency::parallel_for(duint (0), scanSize, [&](duint i)
for(duint i = 0; i < scanSize;)
{
// Print the progress every 4096 bytes
if((i % 0x1000) == 0)
{
// Percent = (current / total) * 100
// Integer = floor(percent)
int percent = (int)floor(((float)i / (float)scanSize) * 100.0f);
cbUpdateProgress(percent);
}
// Disassemble the instruction
int disasmMaxSize = min(MAX_DISASM_BUFFER, (int)(scanSize - i)); // Prevent going past the boundary
int disasmLen = 1;
if(cp.Disassemble(scanStart, data() + i, disasmMaxSize))
{
BASIC_INSTRUCTION_INFO basicinfo;
fillbasicinfo(&cp, &basicinfo);
if(Callback(&cp, &basicinfo, &refInfo))
refInfo.refcount++;
disasmLen = cp.Size();
}
else
{
// Invalid instruction detected, so just skip the byte
}
scanStart += disasmLen;
i += disasmLen;
}
cbUpdateProgress(100);
return refInfo.refcount;
}
/**
* @brief Return the address of the nth instruction after the instruction pointed by ip. @n
* This function has been grabbed from OllyDbg ("Disassembleforward" in asmserv.c)
*
* @param[in] data Address of the data to disassemble
* @param[in] base Original base address of the memory page (Required to disassemble destination addresses)
* @param[in] size Size of the data block pointed by data
* @param[in] ip RVA of the current instruction (Relative to data pointer)
* @param[in] n Number of instruction next
*
* @return Return the RVA (Relative to the data pointer) of the nth instruction after the instruction pointed by ip
*/
ulong QBeaEngine::DisassembleNext(byte_t* data, duint base, duint size, duint ip, int n)
{
int i;
uint cmdsize;
unsigned char* pdata;
// Reset Disasm Structure
Capstone cp;
if(data == NULL)
return 0;
if(ip >= size)
ip = size - 1;
if(n <= 0)
return ip;
pdata = data + ip;
size -= ip;
for(i = 0; i < n && size > 0; i++)
{
if(mCodeFoldingManager && mCodeFoldingManager->isFolded(ip + base))
{
cmdsize = mCodeFoldingManager->getFoldEnd(ip + base) - (ip + base) + 1;
}
else
{
if(!cp.DisassembleSafe(ip + base, pdata, (int)size))
cmdsize = 1;
else
cmdsize = cp.Size();
cmdsize = mEncodeMap->getDataSize(base + ip, cmdsize);
}
pdata += cmdsize;
ip += cmdsize;
size -= cmdsize;
}
return ip;
}
/**
* @brief Return the address of the nth instruction before the instruction pointed by ip. @n
* This function has been grabbed from OllyDbg ("Disassembleback" in asmserv.c)
*
* @param[in] data Address of the data to disassemble
* @param[in] base Original base address of the memory page (Required to disassemble destination addresses)
* @param[in] size Size of the data block pointed by data
* @param[in] ip RVA of the current instruction (Relative to data pointer)
* @param[in] n Number of instruction back
*
* @return Return the RVA (Relative to the data pointer) of the nth instruction before the instruction pointed by ip
*/
ulong QBeaEngine::DisassembleBack(byte_t* data, duint base, duint size, duint ip, int n)
{
int i;
uint abuf[128], addr, back, cmdsize;
unsigned char* pdata;
// Reset Disasm Structure
Capstone cp;
// Check if the pointer is not null
if(data == NULL)
return 0;
// Round the number of back instructions to 127
if(n < 0)
n = 0;
else if(n > 127)
n = 127;
// Check if the instruction pointer ip is not outside the memory range
if(ip >= size)
ip = size - 1;
// Obvious answer
if(n == 0)
return ip;
if(ip < (uint)n)
return ip;
//TODO: buffer overflow due to unchecked "back" value
back = MAX_DISASM_BUFFER * (n + 3); // Instruction length limited to 16
if(ip < back)
back = ip;
addr = ip - back;
if(mCodeFoldingManager && mCodeFoldingManager->isFolded(addr + base))
{
duint newback = mCodeFoldingManager->getFoldBegin(addr + base);
if(newback >= base && newback < size + base)
addr = newback - base;
}
pdata = data + addr;
for(i = 0; addr < ip; i++)
{
abuf[i % 128] = addr;
if(mCodeFoldingManager && mCodeFoldingManager->isFolded(addr + base))
{
duint newaddr = mCodeFoldingManager->getFoldBegin(addr + base);
if(newaddr >= base)
{
addr = newaddr - base;
}
cmdsize = mCodeFoldingManager->getFoldEnd(addr + base) - (addr + base) + 1;
}
else
{
if(!cp.DisassembleSafe(addr + base, pdata, (int)size))
cmdsize = 2; //heuristic for better output (FF FE or FE FF are usually part of an instruction)
else
cmdsize = cp.Size();
cmdsize = mEncodeMap->getDataSize(base + addr, cmdsize);
}
pdata += cmdsize;
addr += cmdsize;
back -= cmdsize;
size -= cmdsize;
}
if(i < n)
return abuf[0];
else
return abuf[(i - n + 128) % 128];
}
void LinearPass::AnalysisWorker(duint Start, duint End, BBlockArray* Blocks)
{
Capstone disasm;
duint blockBegin = Start; // BBlock starting virtual address
duint blockEnd = 0; // BBlock ending virtual address
bool blockPrevPad = false; // Indicator if the last instruction was padding
BasicBlock* lastBlock = nullptr; // Avoid an expensive call to std::vector::back()
int insnCount = 0; // Temporary number of instructions counted for a block
for(duint i = Start; i < End;)
{
if(!disasm.Disassemble(i, TranslateAddress(i), int(End - i)))
{
// Skip instructions that can't be determined
i++;
continue;
}
// Increment counters
i += disasm.Size();
blockEnd = i;
insnCount++;
// The basic block ends here if it is a branch
bool call = disasm.InGroup(CS_GRP_CALL); // CALL
bool jmp = disasm.InGroup(CS_GRP_JUMP); // JUMP
bool ret = disasm.InGroup(CS_GRP_RET); // RETURN
bool padding = disasm.IsFilling(); // INSTRUCTION PADDING
if(padding)
{
// PADDING is treated differently. They are all created as their
// own separate block for more analysis later.
duint realBlockEnd = blockEnd - disasm.Size();
if((realBlockEnd - blockBegin) > 0)
{
// The next line terminates the BBlock before the INT instruction.
// Early termination, faked as an indirect JMP. Rare case.
lastBlock = CreateBlockWorker(Blocks, blockBegin, realBlockEnd, false, false, false, false);
lastBlock->SetFlag(BASIC_BLOCK_FLAG_PREPAD);
blockBegin = realBlockEnd;
lastBlock->InstrCount = insnCount;
insnCount = 0;
}
}
if(call || jmp || ret || padding)
{
// Was this a padding instruction?
if(padding && blockPrevPad)
{
// Append it to the previous block
lastBlock->VirtualEnd = blockEnd;
}
else
{
// Otherwise use the default route: create a new entry
auto block = lastBlock = CreateBlockWorker(Blocks, blockBegin, blockEnd, call, jmp, ret, padding);
// Counters
lastBlock->InstrCount = insnCount;
insnCount = 0;
if(!padding)
{
// Check if absolute jump, regardless of operand
if(disasm.GetId() == X86_INS_JMP)
block->SetFlag(BASIC_BLOCK_FLAG_ABSJMP);
// Figure out the operand type(s)
const auto & operand = disasm.x86().operands[0];
if(operand.type == X86_OP_IMM)
{
// Branch target immediate
block->Target = (duint)operand.imm;
}
else
{
// Indirects (no operand, register, or memory)
block->SetFlag(BASIC_BLOCK_FLAG_INDIRECT);
if(operand.type == X86_OP_MEM &&
operand.mem.base == X86_REG_RIP &&
operand.mem.index == X86_REG_INVALID &&
operand.mem.scale == 1)
{
/*
block->SetFlag(BASIC_BLOCK_FLAG_INDIRPTR);
block->Target = (duint)operand.mem.disp;
*/
}
}
}
}
// Reset the loop variables
blockBegin = i;
blockPrevPad = padding;
}
}
}