IA_IAPI::allInsns_t::const_iterator IA_x86Details::findTableInsn()
{
// Check whether the jump is our table insn!
Expression::Ptr cft = currentBlock->curInsn()->getControlFlowTarget();
if(cft)
{
std::vector<Expression::Ptr> tmp;
cft->getChildren(tmp);
if(tmp.size() == 1)
{
Expression::Ptr cftAddr = tmp[0];
zeroAllGPRegisters z(currentBlock->current);
cftAddr->apply(&z);
parsing_printf("\tChecking indirect jump %s for table insn\n", currentBlock->curInsn()->format().c_str());
if(z.isDefined() && z.getResult())
{
parsing_printf("\tAddress in jump\n");
return currentBlock->curInsnIter;
}
}
}
IA_IAPI::allInsns_t::const_iterator c = currentBlock->curInsnIter;
while(!isTableInsn(c->second) && c != currentBlock->allInsns.begin())
{
--c;
}
if(isTableInsn(c->second))
{
return c;
}
return currentBlock->allInsns.end();
}
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;
}
void IA_x86Details::computeTableAddress()
{
// Extract displacement from table insn
Expression::Ptr displacementSrc;
if(tableInsn.insn->getCategory() == c_BranchInsn)
{
Expression::Ptr op = tableInsn.insn->getOperand(0).getValue();
std::vector<Expression::Ptr> tmp;
op->getChildren(tmp);
if(tmp.empty())
{
displacementSrc = op;
}
else
{
displacementSrc = tmp[0];
}
}
else
{
parsing_printf("\tcracking table instruction %s\n", tableInsn.insn->format().c_str());
std::vector<Expression::Ptr> tmp;
Expression::Ptr op = tableInsn.insn->getOperand(1).getValue();
if(!op)
{
parsing_printf("\ttable insn BAD! (no second operand)\n");
return;
}
if(tableInsn.insn->getOperation().getID() != e_lea)
{
op->getChildren(tmp);
if(tmp.empty())
{
parsing_printf("\ttable insn BAD! (not LEA, second operand not a deref)\n");
return;
}
displacementSrc = tmp[0];
}
else
{
displacementSrc = op;
}
}
zeroAllGPRegisters z(tableInsn.addrOfInsn + tableInsn.insn->size());
displacementSrc->apply(&z);
if(!z.isDefined())
{
parsing_printf("\ttable insn: %s, displacement %s, bind of all GPRs FAILED\n",
tableInsn.insn->format().c_str(), displacementSrc->format().c_str());
return;
}
else
{
tableInsn.addrFromInsn = z.getResult();
}
parsing_printf("\ttableInsn.addrFromInsn set to 0x%lx\n",tableInsn.addrFromInsn);
}
void
dyninst_analyze_address_taken(BPatch_addressSpace *handle, DICFG *cfg)
{
/* XXX: this is the most naive address-taken analysis that can be used by the
* lbr_analysis_pass. More sophisticated ones can be (and are) plugged in in the pass.
* This naive solution is provided only for comparison with more sophisticated ones.
*
* This analysis looks for instruction operands that correspond to known function addresses,
* and then marks these functions as having their address taken. In particular, we
* do /not/ look for function pointers stored in (static) memory, or for function
* pointers that are computed at runtime.
*/
SymtabCodeSource *sts;
CodeObject *co;
std::vector<BPatch_object*> objs;
handle->getImage()->getObjects(objs);
assert(objs.size() > 0);
const char *bin = objs[0]->pathName().c_str();
// Create a new binary object
sts = new SymtabCodeSource((char*)bin);
co = new CodeObject(sts);
// Parse the binary
co->parse();
BPatch_image *image = handle->getImage();
std::vector<BPatch_module *> *mods = image->getModules();
std::vector<BPatch_module *>::iterator mods_iter;
for (mods_iter = mods->begin(); mods_iter != mods->end(); mods_iter++) {
std::vector<BPatch_function *> *funcs = (*mods_iter)->getProcedures(false);
std::vector<BPatch_function *>::iterator funcs_iter = funcs->begin();
for(; funcs_iter != funcs->end(); funcs_iter++) {
co->parse((Address)(*funcs_iter)->getBaseAddr(), true);
BPatch_flowGraph *fg = (*funcs_iter)->getCFG();
std::set<BPatch_basicBlock*> blocks;
fg->getAllBasicBlocks(blocks);
std::set<BPatch_basicBlock*>::iterator block_iter;
for (block_iter = blocks.begin(); block_iter != blocks.end(); ++block_iter) {
BPatch_basicBlock *block = (*block_iter);
std::vector<Instruction::Ptr> insns;
block->getInstructions(insns);
std::vector<Instruction::Ptr>::iterator insn_iter;
for (insn_iter = insns.begin(); insn_iter != insns.end(); ++insn_iter) {
Instruction::Ptr ins = *insn_iter;
std::vector<Operand> ops;
ins->getOperands(ops);
std::vector<Operand>::iterator op_iter;
for (op_iter = ops.begin(); op_iter != ops.end(); ++op_iter) {
Expression::Ptr expr = (*op_iter).getValue();
struct OperandAnalyzer : public Dyninst::InstructionAPI::Visitor {
virtual void visit(BinaryFunction* op) {};
virtual void visit(Dereference* op) {}
virtual void visit(Immediate* op) {
address_t addr;
ArmsFunction *func;
switch(op->eval().type) {
case s32:
addr = op->eval().val.s32val;
break;
case u32:
addr = op->eval().val.u32val;
break;
case s64:
addr = op->eval().val.s64val;
break;
case u64:
addr = op->eval().val.u64val;
break;
default:
return;
}
func = cfg_->find_function(addr);
if(func) {
printf("Instruction [%s] references function 0x%jx\n", ins_->format().c_str(), addr);
func->set_addr_taken();
}
}
virtual void visit(RegisterAST* op) {}
OperandAnalyzer(DICFG *cfg, Instruction::Ptr ins) {
cfg_ = cfg;
ins_ = ins;
};
DICFG *cfg_;
Instruction::Ptr ins_;
};
OperandAnalyzer oa(cfg, ins);
expr->apply(&oa);
}
}
}
}
}
}
