bool IA_x86Details::handleAdd(IA_IAPI& block)
{
parsing_printf("\t found add insn %s without obvious thunk\n",
block.getInstruction()->format().c_str());
// Check table insn and bail if it's not of the mov eax, [eax] form
// We do this indirectly: if there was already a displacment that we
// could find in the table insn, we have a "table address"; otherwise, check adds
if(tableInsn.addrFromInsn != 0)
{
return false;
}
// Use the add operand as our table base; we're handling tables of the form:
// <reg = index>
// add reg, $base
// mov reg, [reg]
// jmp *reg
Expression::Ptr addExpr = block.getInstruction()->getOperand(1).getValue();
zeroAllGPRegisters z(block.getAddr());
addExpr->apply(&z);
thunkInsn.insn = block.getInstruction();
thunkInsn.addrFromInsn = z.getResult();
thunkInsn.addrOfInsn = block.getAddr();
parsing_printf("\t setting thunk offset to 0x%lx (EXPERIMENTAL!)\n", thunkInsn.addrFromInsn);
return thunkInsn.addrFromInsn != 0;
}
bool IA_x86Details::handleCall(IA_IAPI& block)
{
parsing_printf("\tchecking call at 0x%lx for thunk\n", block.getAddr());
if(!block.isRealCall())
{
parsing_printf("\tthunk found at 0x%lx, checking for add\n", block.getAddr());
block.advance();
thunkInsn.addrFromInsn = block.getAddr();
Instruction::Ptr addInsn = block.getInstruction();
if(addInsn)
parsing_printf("\tinsn after thunk: %s\n", addInsn->format().c_str());
else
parsing_printf("\tNO INSN after thunk at 0x%lx\n", thunkInsn.addrFromInsn);
if(addInsn)
{
std::set<RegisterAST::Ptr> boundRegs;
if(addInsn->getOperation().getID() == e_pop)
{
addInsn->getWriteSet(boundRegs);
block.advance();
addInsn = block.getInstruction();
}
if(addInsn && ((addInsn->getOperation().getID() == e_add) ||
(addInsn->getOperation().getID() == e_lea)))
{
Expression::Ptr op0 = addInsn->getOperand(0).getValue();
Expression::Ptr op1 = addInsn->getOperand(1).getValue();
for(std::set<RegisterAST::Ptr>::const_iterator curReg = boundRegs.begin();
curReg != boundRegs.end();
++curReg)
{
op0->bind(curReg->get(), Result(u64, 0));
op1->bind(curReg->get(), Result(u64, 0));
}
Result imm = addInsn->getOperand(1).getValue()->eval();
Result imm2 = addInsn->getOperand(0).getValue()->eval();
if(imm.defined)
{
Address thunkDiff = imm.convert<Address>();
parsing_printf("\tsetting thunkInsn.addrFromInsn to 0x%lx (0x%lx + 0x%lx)\n",
thunkInsn.addrFromInsn+thunkDiff, thunkInsn.addrFromInsn, thunkDiff);
thunkInsn.addrOfInsn = block.getPrevAddr();
thunkInsn.addrFromInsn = thunkInsn.addrFromInsn + thunkDiff;
return true;
}
else if(imm2.defined)
{
Address thunkDiff = imm2.convert<Address>();
parsing_printf("\tsetting thunkInsn.addrFromInsn to 0x%lx (0x%lx + 0x%lx)\n",
thunkInsn.addrFromInsn+thunkDiff, thunkInsn.addrFromInsn, thunkDiff);
thunkInsn.addrOfInsn = block.getPrevAddr();
thunkInsn.addrFromInsn = thunkInsn.addrFromInsn + thunkDiff;
return true;
}
else
{
parsing_printf("\tadd insn %s found following thunk at 0x%lx, couldn't bind operands!\n",
addInsn->format().c_str(), thunkInsn.addrFromInsn);
}
}
}
thunkInsn.addrFromInsn = 0;
}
thunkInsn.addrFromInsn = 0;
thunkInsn.addrOfInsn = 0;
thunkInsn.insn.reset();
return false;
}
