void
InitPointerToNull::visit(SgNode* node) {
if (isSgAsmFunction(node)) {
memoryWrites.clear();
memoryRead.clear();
} else
if (isSgAsmx86Instruction(node) && isSgAsmx86Instruction(node)->get_kind() == x86_mov) {
// this is the address of the mov instruction prior to the call
//rose_addr_t resolveAddr=0;
SgAsmx86Instruction* inst = isSgAsmx86Instruction(node);
SgNode* instBlock = NULL;
if (project)
instBlock= isSgAsmBlock(inst->get_parent());
else //we run IDA, this is different
instBlock=inst;
if (instBlock==NULL)
return;
SgAsmFunction* instFunc = isSgAsmFunction(instBlock->get_parent());
if (instFunc==NULL)
return;
// we have found a mov instruction
// we need to check if it is a mov mem, (value or reg) // assignment of variable // forgot mov mem, mem
// or we find a mov reg, mem // usage of variable
// make sure a variable is assigned before used
SgAsmOperandList * ops = inst->get_operandList();
SgAsmExpressionPtrList& opsList = ops->get_operands();
SgAsmExpressionPtrList::iterator itOP = opsList.begin();
SgAsmMemoryReferenceExpression* memL=NULL;
SgAsmMemoryReferenceExpression* memR=NULL;
SgAsmRegisterReferenceExpression* regL=NULL;
SgAsmRegisterReferenceExpression* regR=NULL;
SgAsmValueExpression* Val = NULL;
int iteration=0;
for (;itOP!=opsList.end();++itOP) {
SgAsmExpression* exp = *itOP;
ROSE_ASSERT(exp);
if (iteration==1) {
// right hand side
memR = isSgAsmMemoryReferenceExpression(exp);
regR = isSgAsmRegisterReferenceExpression(exp);
Val = isSgAsmValueExpression(exp);
}
if (iteration==0) {
// left hand side
memL = isSgAsmMemoryReferenceExpression(exp);
regL = isSgAsmRegisterReferenceExpression(exp);
iteration++;
}
} //for
if ((memL && regR) || (memL && Val) || (memL && memR)) {
// could be assignment to address
rose_addr_t addr=BinQSupport::evaluateMemoryExpression(inst,memL);
// apparently the reference to memory does not always have to be BP but
// can also be IP if it is a static variable. How will we handle global variables?
//bool containsBP = BinQSupport::memoryExpressionContainsRegister(x86_regclass_gpr,x86_gpr_bp, memL);
//if (containsBP) {
// this is memory write with offset to BP
// remember this memory location as a write
if (debug)
cerr << "found a memory write (REG) : " << RoseBin_support::HexToString(inst->get_address())<<" "<<unparseInstruction(inst)<<endl;
memoryWrites.insert(addr);
//}
} else if (regL && memR) {
// could be usage of address
rose_addr_t addr=BinQSupport::evaluateMemoryExpression(inst,memR);
bool containsBP = BinQSupport::memoryExpressionContainsRegister(x86_regclass_gpr,x86_gpr_bp, memR);
if (containsBP) {
// this is memory read with offset to BP
// did we see a write for this? If not, it is not initialized!
std::set<rose_addr_t>::const_iterator it = memoryWrites.find(addr);
if (it!=memoryWrites.end()) {
// found write, everything is good
if (debug)
cerr << "found a read with matching write : " << RoseBin_support::HexToString(inst->get_address())<<" "<<unparseInstruction(inst)<<endl;
} else {
std::set<rose_addr_t>::const_iterator it2 = memoryRead.find(addr);
if (it2!=memoryRead.end()) {
// found this case before
} else {
if (debug)
cerr << " This variable might not be initialized : " << RoseBin_support::HexToString(inst->get_address())<<" "<< unparseInstruction(inst) << endl;
string res = "Possibly uninitialized variable: ";
string funcname="";
SgAsmBlock* b = isSgAsmBlock(inst->get_parent());
SgAsmFunction* func = NULL;
if (b)
func=isSgAsmFunction(b->get_parent());
if (func)
funcname = func->get_name();
res+=" ("+RoseBin_support::HexToString(inst->get_address())+") : "+unparseInstruction(inst)+
" <"+inst->get_comment()+"> in function: "+funcname;
result[inst]= res;
memoryRead.insert(addr);
}
}
}
}
}
}
void
RoseBin_FlowAnalysis::process_jumps() {
if (RoseBin_support::DEBUG_MODE())
cerr << "\n >>>>>>>>> processing jumps ... " << endl;
rose_hash::unordered_map <uint64_t, SgAsmInstruction* >::iterator it;
for (it=rememberInstructions.begin();it!=rememberInstructions.end();++it) {
SgAsmx86Instruction* inst = isSgAsmx86Instruction(it->second);
if (inst->get_kind() == x86_call) {
//cerr << "Found call at " << std::hex << inst->get_address() << endl;
SgAsmx86Instruction* target = isSgAsmx86Instruction(process_jumps_get_target(inst));
if (target) {
//cerr << "Target is " << std::hex << target->get_address() << endl;
// inst->get_targets().push_back(target);
// we set the sources (for each node)
ROSE_ASSERT(g_algo->info);
g_algo->info->incomingEdges[target].insert(inst->get_address());
// tps: changed this algorithm so that it runs in
// linear time!
ROSE_ASSERT (target->get_parent());
if (target->get_parent()) {
// ROSE_ASSERT(target->get_parent());
SgAsmNode* b_b = target;
if (!db)
b_b = isSgAsmNode(target->get_parent());
ROSE_ASSERT(b_b);
SgAsmFunction* b_func = isSgAsmFunction(b_b->get_parent());
if (b_func) {
// (16/Oct/07) tps: this is tricky, it appears that sometimes the target can
// be just a jmp to a new location, so we should forward this information to the correct
// function.
// Therefore we need to check if the current function has a return statement.
// If not, we want to forward this information.
if (target->get_kind() == x86_jmp) {
//cerr << " >>>>>>>> found a jmp target - number of children: " << b_func->get_traversalSuccessorContainer().size() << endl;
if (b_func->get_numberOfTraversalSuccessors()==1) {
SgAsmx86Instruction* target2 = isSgAsmx86Instruction(process_jumps_get_target(inst));
if (target2) {
b_b = target2;
if (!db)
b_b = isSgAsmNode(target2->get_parent());
b_func = isSgAsmFunction(b_b->get_parent());
}
}
}
if (inst->get_parent()) {
//cerr << "Inst has a parent" << endl;
if (inst->get_comment()=="")
inst->set_comment(""+b_func->get_name());
ROSE_ASSERT(g_algo->info);
SgAsmInstruction* inst_after = g_algo->info->getInstructionAtAddress(inst->get_address() + inst->get_raw_bytes().size()); // inst->cfgBinFlowOutEdge(info);
if (inst_after) {
//cerr << "Added dest " << std::hex << isSgAsmStatement(inst_after)->get_address() << " for function" << endl;
b_func->append_dest(isSgAsmStatement(inst_after));
}
}
} else {
if (RoseBin_support::DEBUG_MODE())
cerr << " NO FUNCTION DETECTED ABOVE BLOCK . " << endl;
}
} else {
if (RoseBin_support::DEBUG_MODE())
cerr << " WARNING :: process_jumps: target has no parent ... i.e. no FunctionDeclaration to it " <<
target->class_name() << endl;
}
} else {
if (inst)
if (RoseBin_support::DEBUG_MODE())
cerr << " WARNING :: process_jumps: No target found for node " << RoseBin_support::HexToString(inst->get_address())
<< " " << inst->get_mnemonic() << endl;
}
} else {
// might be a jmp
SgAsmx86Instruction* target = isSgAsmx86Instruction(process_jumps_get_target(inst));
if (target) {
// inst->get_targets().push_back(target);
// we set the sources (for each node)
ROSE_ASSERT(g_algo->info);
g_algo->info->incomingEdges[target].insert(inst->get_address());
}
}
}
//cerr << "\n >>>>>>>>> processing jumps ... done. " << endl;
// cerr << "\n >>>>>>>>> resolving RET jumps ... " << endl;
rose_hash::unordered_map <uint64_t, SgAsmInstruction* >::iterator it2;
for (it2=rememberInstructions.begin();it2!=rememberInstructions.end();++it2) {
//int id = it2->first;
SgAsmx86Instruction* target = isSgAsmx86Instruction(it2->second);
ROSE_ASSERT (target);
#if 1
if (target->get_kind() == x86_ret) {
SgAsmNode* b_b = target;
if (!db)
b_b = isSgAsmNode(target->get_parent());
SgAsmFunction* parent = isSgAsmFunction(b_b->get_parent());
if (parent) {
//ROSE_ASSERT(parent);
std::vector <SgAsmStatement*> dest_list = parent->get_dest();
for (size_t i = 0; i < dest_list.size(); ++i) {
ROSE_ASSERT (isSgAsmInstruction(dest_list[i]));
//cerr << "Adding ret target " << std::hex << dest_list[i]->get_address() << " to " << std::hex << target->get_address() << endl;
//info->indirectJumpAndReturnTargets[target].insert(dest_list[i]->get_address());
ROSE_ASSERT(g_algo->info);
g_algo->info->incomingEdges[isSgAsmInstruction(dest_list[i])].insert(target->get_address());
}
std::vector <SgAsmStatement*>::iterator it3 = dest_list.begin();
for (; it3!=dest_list.end();++it3) {
SgAsmInstruction* dest = isSgAsmInstruction(*it3);
if (dest) {
dest->append_sources(target);
//cerr << " appending source to " << dest->get_address() << " target: " << target->get_address() << endl;
}
} // for
} else { // if parent
if (RoseBin_support::DEBUG_MODE())
cerr << " ERROR :: RET jumps :: no parent found for ret : " << target->class_name() << endl;
//exit (0);
}
} // if ret
#endif
}
if (RoseBin_support::DEBUG_MODE())
cerr << " >>>>>>>>> resolving RET jumps ... done." << endl;
}
