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#include "DxeResolver.h"
bool DxeResolver::resolveBootServices()
{
auto refs = m_view->GetCodeReferencesForType(QualifiedName("EFI_BOOT_SERVICES"));
// search reference of `EFI_BOOT_SERVICES` so that we can easily parse different services
for (auto& ref : refs) {
if (m_task->IsCancelled())
return false;
auto func = ref.func;
auto mlil = func->GetMediumLevelIL();
if (!mlil)
continue;
auto mlilSsa = mlil->GetSSAForm();
size_t mlilIdx = mlil->GetInstructionStart(m_view->GetDefaultArchitecture(), ref.addr);
auto instr = mlilSsa->GetInstruction(mlil->GetSSAInstructionIndex(mlilIdx));
if (instr.operation == MLIL_CALL_SSA || instr.operation == MLIL_TAILCALL_SSA) {
auto dest = instr.GetDestExpr();
if (dest.operation != MLIL_LOAD_STRUCT_SSA)
continue;
auto offset = dest.GetOffset();
if (offset == 0x18 + m_width * 16 || offset == 0x18 + m_width * 32) {
// HandleProtocol, OpenProtocol
// Guid:1, Interface:2
resolveGuidInterface(ref.func, ref.addr, 1, 2);
} else if (offset == 0x18 + m_width * 37) {
// LocateProtocol
resolveGuidInterface(ref.func, ref.addr, 0, 2);
}
}
}
return true;
}
bool DxeResolver::resolveRuntimeServices()
{
auto refs = m_view->GetCodeReferencesForType(QualifiedName("EFI_RUNTIME_SERVICES"));
for (auto &ref : refs) {
if (m_task->IsCancelled())
return false;
auto func = ref.func;
auto mlil = func->GetMediumLevelIL();
if (!mlil)
continue;
auto mlilSsa = mlil->GetSSAForm();
size_t mlilIdx = mlil->GetInstructionStart(m_view->GetDefaultArchitecture(), ref.addr);
auto instr = mlilSsa->GetInstruction(mlil->GetSSAInstructionIndex(mlilIdx));
if (instr.operation == MLIL_CALL_SSA || instr.operation == MLIL_TAILCALL_SSA) {
auto dest = instr.GetDestExpr();
if (dest.operation != MLIL_LOAD_STRUCT_SSA)
continue;
auto offset = dest.GetOffset();
if (offset == 0x18 + m_width * 6 || offset == 0x18 + m_width * 8) {
// TODO implement this
// GetVariable and SetVariable
}
}
}
return true;
}
bool DxeResolver::resolveSmmTables(string serviceName, string tableName)
{
auto refs = m_view->GetCodeReferencesForType(QualifiedName(serviceName));
// both versions use the same type, so we only need to search for this one
for (auto &ref : refs) {
if (m_task->IsCancelled())
return false;
auto func = ref.func;
auto mlil = func->GetMediumLevelIL();
if (!mlil)
continue;
auto mlilSsa = mlil->GetSSAForm();
size_t mlilIdx = mlil->GetInstructionStart(m_view->GetDefaultArchitecture(), ref.addr);
auto instr = mlilSsa->GetInstruction(mlil->GetSSAInstructionIndex(mlilIdx));
if (instr.operation != MLIL_CALL_SSA && instr.operation != MLIL_TAILCALL_SSA)
continue;
auto destExpr = instr.GetDestExpr();
if (destExpr.operation != MLIL_LOAD_STRUCT_SSA)
continue;
if (destExpr.GetOffset() != 8)
continue;
auto params = instr.GetParameterExprs();
if (params.size() < 2)
continue;
auto smstAddr = params[1];
if (smstAddr.operation != MLIL_CONST_PTR)
continue;
QualifiedNameAndType result;
string errors;
bool ok = m_view->ParseTypeString(tableName, result, errors);
if (!ok)
return false;
m_view->DefineDataVariable(smstAddr.GetValue().value, result.type);
m_view->DefineUserSymbol(new Symbol(DataSymbol, "gMmst", smstAddr.GetValue().value));
m_view->UpdateAnalysisAndWait();
}
return true;
}
bool DxeResolver::resolveSmmServices()
{
auto refs = m_view->GetCodeReferencesForType(QualifiedName("EFI_MM_SYSTEM_TABLE"));
auto refs_smm = m_view->GetCodeReferencesForType(QualifiedName("EFI_SMM_SYSTEM_TABLE2"));
// These tables have same type information, we can just iterate once
refs.insert(refs.end(), refs_smm.begin(), refs_smm.end());
for (auto &ref : refs) {
if (m_task->IsCancelled())
return false;
auto func = ref.func;
auto mlil = func->GetMediumLevelIL();
if (!mlil)
continue;
auto mlilSsa = mlil->GetSSAForm();
size_t mlilIdx = mlil->GetInstructionStart(m_view->GetDefaultArchitecture(), ref.addr);
auto instr = mlilSsa->GetInstruction(mlil->GetSSAInstructionIndex(mlilIdx));
if (instr.operation == MLIL_CALL_SSA || instr.operation == MLIL_TAILCALL_SSA) {
auto dest = instr.GetDestExpr();
if (dest.operation != MLIL_LOAD_STRUCT_SSA)
continue;
auto offset = dest.GetOffset();
if (offset == 0x18 + m_width * 0x14) {
// SmmHandleProtocol
resolveGuidInterface(ref.func, ref.addr, 1, 2);
} else if (offset == 0x18 + m_width * 0x17) {
// SmmLocateProtocol
resolveGuidInterface(ref.func, ref.addr, 0, 2);
}
}
}
return true;
}
bool DxeResolver::resolveSmiHandlers()
{
auto refs = m_view->GetCodeReferencesForType(QualifiedName("EFI_MM_SW_REGISTER"));
for (auto &ref : refs)
{
if (m_task->IsCancelled())
return false;
auto func = ref.func;
auto mlil = func->GetMediumLevelIL();
if (!mlil)
continue;
auto mlilSsa = mlil->GetSSAForm();
size_t mlilIdx = mlil->GetInstructionStart(m_view->GetDefaultArchitecture(), ref.addr);
auto instr = mlilSsa->GetInstruction(mlil->GetSSAInstructionIndex(mlilIdx));
if (instr.operation == MLIL_CALL_SSA || instr.operation == MLIL_TAILCALL_SSA)
{
auto dest = instr.GetDestExpr();
if (dest.operation != MLIL_LOAD_STRUCT_SSA)
continue;
auto offset = dest.GetOffset();
if (offset == 0) {
/* EFI_MM_SW_REGISTER, we want to rename the second parameter according to the third parameter
typedef enum EFI_STATUS (* EFI_MM_SW_REGISTER)(
struct EFI_MM_SW_DISPATCH_PROTOCOL* This,
EFI_MM_HANDLER_ENTRY_POINT DispatchFunction,
struct EFI_MM_SW_REGISTER_CONTEXT*
RegisterContext, EFI_HANDLE* DispatchHandle); */
auto parameters = instr.GetParameterExprs();
if (parameters.size() < 3)
continue;
auto dispatchFunction = parameters[1];
auto registerContext = parameters[2];
// Determine the function name according to the registerContext
/* struct EFI_MM_SW_REGISTER_CONTEXT
* {
* UINTN SwMmiInputValue;
* };
*/
string funcName = "SmiHandler";
if (dispatchFunction.operation != MLIL_CONST_PTR)
continue;
auto funcAddr = static_cast<uint64_t> (dispatchFunction.GetConstant());
auto targetFunc = m_view->GetAnalysisFunction(m_view->GetDefaultPlatform(), funcAddr);
auto funcType = targetFunc->GetType();
// typedef enum
string handleTypeStr = "EFI_STATUS SmiHandler(EFI_HANDLE DispatchHandle, VOID* Context, VOID* CommBuffer, UINTN* CommBufferSize);";
QualifiedNameAndType result;
string errors;
bool ok = m_view->ParseTypeString(handleTypeStr, result, errors);
if (!ok)
return false;
targetFunc->SetUserType(result.type);
m_view->DefineUserSymbol(new Symbol(FunctionSymbol, funcName, funcAddr));
m_view->UpdateAnalysisAndWait();
// After setting the type, we want to propagate the parameters' type
TypePropagation propagator(m_view);
propagator.propagateFuncParamTypes(targetFunc);
}
}
}
return true;
}
bool DxeResolver::resolveDxe()
{
if (!resolveBootServices())
return false;
if (!resolveRuntimeServices())
return false;
return true;
}
bool DxeResolver::resolveSmm()
{
if (!resolveSmmTables("EFI_SMM_GET_SMST_LOCATION2", "EFI_SMM_SYSTEM_TABLE2*"))
return false;
if (!resolveSmmTables("EFI_MM_GET_MMST_LOCATION", "EFI_MM_SYSTEM_TABLE*"))
return false;
if (!resolveSmmServices())
return false;
if (!resolveSmiHandlers())
return false;
return true;
}
DxeResolver::DxeResolver(Ref<BinaryView> view, Ref<BackgroundTask> task)
: Resolver(view, task)
{
initProtocolMapping();
setModuleEntry(DXE);
}
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