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#include "TypePropagation.h"
#include "highlevelilinstruction.h"
TypePropagation::TypePropagation(BinaryView* view)
{
m_view = view;
m_queue.clear();
m_platform = view->GetDefaultPlatform();
}
const std::map<std::string, std::string> defaultName = {{"EFI_SYSTEM_TABLE", "gST"}, {"EFI_BOOT_SERVICES", "gBS"},
{"EFI_RUNTIME_SERVICES", "gRT"}, {"EFI_MM_SYSTEM_TABLE", "gMmst"}, {"EFI_SMM_SYSTEM_TABLE2", "gSmmst"},
{"EFI_HANDLE", "gHandle"}};
bool TypePropagation::propagateFuncParamTypes(Function* func)
{
m_queue.push_back(func->GetStart());
LogDebugF("Start Type propagation from {:#x}", func->GetStart());
while (!m_queue.empty())
{
uint64_t addr = m_queue.front();
m_queue.pop_front();
Ref<Function> target_func = m_view->GetAnalysisFunction(m_platform, addr);
auto params = target_func->GetType()->GetParameters();
bool update = false;
auto param_vars = target_func->GetParameterVariables().GetValue();
for (auto var : param_vars)
{
bool propagate = false;
auto var_type = target_func->GetVariableType(var).GetValue();
if (var_type->IsPointer())
{
Ref<Type> target_type = var_type->GetChildType().GetValue();
if (target_type->IsPointer() || target_type->IsNamedTypeRefer())
propagate = true;
}
else if (var_type->IsNamedTypeRefer())
{
Ref<Type> target_type = m_view->GetTypeById(var_type->GetNamedTypeReference()->GetTypeId());
if (target_type->IsPointer())
propagate = true;
}
if (!propagate)
continue;
// Check whether the param is an aliased var. If it's an aliased var, it may not be directly used in the
// function
Ref<HighLevelILFunction> hlil_func_ssa = target_func->GetHighLevelIL()->GetSSAForm();
std::set<Variable> aliased_vars = target_func->GetHighLevelILAliasedVariables();
auto it = aliased_vars.find(var);
if (it == aliased_vars.end())
{
// not an aliaed var, use version 0
update |= propagateFuncParamTypes(target_func, SSAVariable(var, 0));
}
else
{
// this param is an aliased var, get the ssa_var
auto uses = target_func->GetHighLevelIL()->GetVariableUses(var);
for (auto use : uses)
{
auto hlil_instr = target_func->GetHighLevelIL()->GetExpr(use);
hlil_instr = hlil_instr.GetParent();
if (hlil_instr.operation != HLIL_VAR_INIT)
continue;
SSAVariable ssa_var = hlil_instr.GetSSAForm().GetDestSSAVariable();
update |= propagateFuncParamTypes(target_func, ssa_var);
}
}
}
if (update)
m_view->UpdateAnalysisAndWait();
}
return true;
}
bool TypePropagation::propagateFuncParamTypes(Function* func, SSAVariable ssa_var)
{
bool update = false;
auto mlil_func_ssa = func->GetMediumLevelIL()->GetSSAForm();
auto uses = mlil_func_ssa->GetSSAVarUses(ssa_var);
for (auto use : uses)
{
auto instr = mlil_func_ssa->GetInstruction(use);
switch (instr.operation)
{
case MLIL_CALL_SSA:
case MLIL_TAILCALL_SSA:
{
// propagate variable type to sub function
auto dest = instr.GetDestExpr();
if (!dest.GetValue().IsConstant())
continue;
Ref<Function> subfunc = m_view->GetAnalysisFunction(m_platform, dest.GetValue().value);
if (!subfunc)
continue;
auto subfunc_type = subfunc->GetType();
auto subfunc_params = subfunc->GetType()->GetParameters();
auto instr_params = instr.GetParameterExprs();
for (int i = 0; i < instr_params.size(); i++)
{
if (instr_params[i].operation != MLIL_VAR_SSA)
continue;
if (instr_params[i].GetSourceSSAVariable() != ssa_var)
continue;
if (i >= subfunc_params.size())
break;
auto ssa_var_type = func->GetVariableType(ssa_var.var).GetValue();
auto typeName = GetOriginalTypeName(ssa_var_type);
auto changeFuncType =
[](BinaryView* bv, Ref<Type> funcType, std::string paramName, Ref<Type> paramType, int paramIdx) {
auto newFuncType = TypeBuilder(funcType);
auto adjustedParams = newFuncType.GetParameters();
adjustedParams.at(paramIdx) = FunctionParameter(paramName, paramType);
newFuncType.SetParameters(adjustedParams);
return newFuncType.Finalize();
};
subfunc->SetUserType(
changeFuncType(m_view, subfunc_type, GetVarNameForTypeStr(typeName), ssa_var_type, i));
m_view->UpdateAnalysisAndWait();
if (std::find(m_queue.begin(), m_queue.end(), subfunc->GetStart()) == m_queue.end())
m_queue.push_back(subfunc->GetStart());
update = true;
break;
}
break;
}
case MLIL_STORE_SSA:
{
auto target = instr.GetDestExpr<MLIL_STORE_SSA>();
if (!target.GetValue().IsConstant())
continue;
auto constant = target.GetValue().value;
auto ssa_var_type = func->GetVariableType(ssa_var.var).GetValue();
auto typeName = GetOriginalTypeName(ssa_var_type);
auto it = defaultName.find(typeName);
if (it != defaultName.end())
typeName = it->second;
m_view->DefineDataVariable(constant, ssa_var_type);
m_view->DefineUserSymbol(new Symbol(DataSymbol, typeName, constant));
update = true;
break;
}
case MLIL_SET_VAR_SSA:
{
auto src = instr.GetSourceExpr<MLIL_SET_VAR_SSA>();
auto dest = instr.GetDestSSAVariable<MLIL_SET_VAR_SSA>();
auto dest_type = func->GetVariableType(dest.var);
Confidence<Ref<Type>> src_type;
switch (src.operation)
{
case MLIL_VAR_SSA:
src_type = func->GetVariableType(src.GetSourceSSAVariable().var);
break;
case MLIL_LOAD_SSA:
case MLIL_LOAD_STRUCT_SSA:
src_type = src.GetType();
break;
default:
continue;
}
if (src_type.GetValue() && src_type.GetValue() != dest_type.GetValue())
{
func->CreateUserVariable(dest.var, src_type, func->GetVariableName(dest.var));
update |= propagateFuncParamTypes(func, SSAVariable(dest.var, dest.version));
}
break;
}
default:
LogInfoF("Not handled case during type propagation. At {:#x}: {}", instr.address, instr.operation);
break;
}
}
return update;
}
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