Files
windows-user-space-emulator/src/windows-emulator/windows_emulator.cpp
2025-02-10 17:28:00 +01:00

577 lines
18 KiB
C++

#include "std_include.hpp"
#include "windows_emulator.hpp"
#include "cpu_context.hpp"
#include <unicorn_x64_emulator.hpp>
#include <utils/io.hpp>
#include <utils/finally.hpp>
#include <utils/compression.hpp>
#include <utils/lazy_object.hpp>
#include "exception_dispatch.hpp"
#include "apiset/apiset.hpp"
constexpr auto MAX_INSTRUCTIONS_PER_TIME_SLICE = 100000;
namespace
{
void adjust_working_directory(application_settings& app_settings)
{
if (!app_settings.working_directory.empty())
{
// Do nothing
}
#ifdef OS_WINDOWS
else if (app_settings.application.is_relative())
{
app_settings.working_directory = std::filesystem::current_path();
}
#endif
else
{
app_settings.working_directory = app_settings.application.parent();
}
}
void adjust_application(application_settings& app_settings)
{
if (app_settings.application.is_relative())
{
app_settings.application = app_settings.working_directory / app_settings.application;
}
}
void fixup_application_settings(application_settings& app_settings)
{
adjust_working_directory(app_settings);
adjust_application(app_settings);
}
void perform_context_switch_work(windows_emulator& win_emu)
{
auto& devices = win_emu.process.devices;
// Crappy mechanism to prevent mutation while iterating.
const auto was_blocked = devices.block_mutation(true);
const auto _ = utils::finally([&] { devices.block_mutation(was_blocked); });
for (auto& dev : devices | std::views::values)
{
dev.work(win_emu);
}
}
emulator_thread* get_thread_by_id(process_context& process, const uint32_t id)
{
for (auto& t : process.threads | std::views::values)
{
if (t.id == id)
{
return &t;
}
}
return nullptr;
}
bool switch_to_thread(windows_emulator& win_emu, emulator_thread& thread, const bool force = false)
{
if (thread.is_terminated())
{
return false;
}
auto& emu = win_emu.emu();
auto& context = win_emu.process;
const auto is_ready = thread.is_thread_ready(context);
if (!is_ready && !force)
{
return false;
}
auto* active_thread = context.active_thread;
if (active_thread == &thread)
{
thread.setup_if_necessary(emu, context);
return true;
}
if (active_thread)
{
win_emu.log.print(color::dark_gray, "Performing thread switch: %X -> %X\n", active_thread->id, thread.id);
active_thread->save(emu);
}
context.active_thread = &thread;
thread.restore(emu);
thread.setup_if_necessary(emu, context);
return true;
}
bool switch_to_thread(windows_emulator& win_emu, const handle thread_handle)
{
auto* thread = win_emu.process.threads.get(thread_handle);
if (!thread)
{
throw std::runtime_error("Bad thread handle");
}
return switch_to_thread(win_emu, *thread);
}
bool switch_to_next_thread(windows_emulator& win_emu)
{
perform_context_switch_work(win_emu);
auto& context = win_emu.process;
bool next_thread = false;
for (auto& t : context.threads | std::views::values)
{
if (next_thread)
{
if (switch_to_thread(win_emu, t))
{
return true;
}
continue;
}
if (&t == context.active_thread)
{
next_thread = true;
}
}
for (auto& t : context.threads | std::views::values)
{
if (switch_to_thread(win_emu, t))
{
return true;
}
}
return false;
}
}
std::unique_ptr<x64_emulator> create_default_x64_emulator()
{
return unicorn::create_x64_emulator();
}
windows_emulator::windows_emulator(application_settings app_settings, const emulator_settings& settings,
emulator_callbacks callbacks, std::unique_ptr<x64_emulator> emu)
: windows_emulator(settings, std::move(emu))
{
this->callbacks = std::move(callbacks);
fixup_application_settings(app_settings);
this->setup_process(app_settings, settings);
}
windows_emulator::windows_emulator(const emulator_settings& settings, std::unique_ptr<x64_emulator> emu)
: emu_(std::move(emu)),
emulation_root{settings.emulation_root.empty() ? settings.emulation_root : absolute(settings.emulation_root)},
file_sys(emulation_root.empty() ? emulation_root : emulation_root / "filesys"),
memory(*this->emu_),
registry(emulation_root.empty() ? settings.registry_directory : emulation_root / "registry"),
mod_manager(memory, file_sys),
process(*this->emu_, memory)
{
#ifndef OS_WINDOWS
if (this->emulation_root.empty())
{
throw std::runtime_error("Emulation root directory can not be empty!");
}
#endif
for (const auto& mapping : settings.path_mappings)
{
this->file_sys.map(mapping.first, mapping.second);
}
for (const auto& mapping : settings.port_mappings)
{
this->map_port(mapping.first, mapping.second);
}
this->verbose_calls = settings.verbose_calls;
this->silent_until_main_ = settings.silent_until_main && !settings.disable_logging;
this->use_relative_time_ = settings.use_relative_time;
this->log.disable_output(settings.disable_logging || this->silent_until_main_);
this->modules_ = settings.modules;
this->setup_hooks();
}
windows_emulator::~windows_emulator() = default;
void windows_emulator::setup_process(const application_settings& app_settings, const emulator_settings& emu_settings)
{
auto& emu = this->emu();
auto& context = this->process;
auto* exe = this->mod_manager.map_module(app_settings.application, this->log, true);
const auto apiset_data = apiset::obtain(this->emulation_root);
this->process.setup(this->emu(), this->memory, app_settings, emu_settings, exe->image_base, apiset_data);
context.executable = exe;
context.ntdll = this->mod_manager.map_module(R"(C:\Windows\System32\ntdll.dll)", this->log, true);
context.win32u = this->mod_manager.map_module(R"(C:\Windows\System32\win32u.dll)", this->log, true);
const auto ntdll_data = emu.read_memory(context.ntdll->image_base, context.ntdll->size_of_image);
const auto win32u_data = emu.read_memory(context.win32u->image_base, context.win32u->size_of_image);
this->dispatcher.setup(context.ntdll->exports, ntdll_data, context.win32u->exports, win32u_data);
context.ldr_initialize_thunk = context.ntdll->find_export("LdrInitializeThunk");
context.rtl_user_thread_start = context.ntdll->find_export("RtlUserThreadStart");
context.ki_user_exception_dispatcher = context.ntdll->find_export("KiUserExceptionDispatcher");
context.default_register_set = emu.save_registers();
const auto main_thread_id = context.create_thread(this->memory, context.executable->entry_point, 0, 0);
switch_to_thread(*this, main_thread_id);
}
void windows_emulator::yield_thread()
{
this->switch_thread_ = true;
this->emu().stop();
}
void windows_emulator::perform_thread_switch()
{
this->switch_thread_ = false;
while (!switch_to_next_thread(*this))
{
// TODO: Optimize that
std::this_thread::sleep_for(1ms);
}
}
bool windows_emulator::activate_thread(const uint32_t id)
{
const auto thread = get_thread_by_id(this->process, id);
if (!thread)
{
return false;
}
return switch_to_thread(*this, *thread, true);
}
void windows_emulator::on_instruction_execution(const uint64_t address)
{
auto& thread = this->current_thread();
++this->process.executed_instructions;
const auto thread_insts = ++thread.executed_instructions;
if (thread_insts % MAX_INSTRUCTIONS_PER_TIME_SLICE == 0)
{
this->yield_thread();
}
this->process.previous_ip = this->process.current_ip;
this->process.current_ip = this->emu().read_instruction_pointer();
const auto binary = utils::make_lazy([&] {
return this->mod_manager.find_by_address(address); //
});
const auto previous_binary = utils::make_lazy([&] {
return this->mod_manager.find_by_address(this->process.previous_ip); //
});
const auto is_in_interesting_module = [&] {
if (this->modules_.empty())
{
return false;
}
return (binary && this->modules_.contains(binary->name)) ||
(previous_binary && this->modules_.contains(previous_binary->name));
};
const auto is_main_exe = this->process.executable->is_within(address);
const auto is_interesting_call = process.executable->is_within(this->process.previous_ip) //
|| is_main_exe //
|| is_in_interesting_module();
if (this->silent_until_main_ && is_main_exe)
{
this->silent_until_main_ = false;
this->log.disable_output(false);
}
if (!this->verbose && !this->verbose_calls && !is_interesting_call)
{
return;
}
if (binary)
{
const auto export_entry = binary->address_names.find(address);
if (export_entry != binary->address_names.end())
{
const auto rsp = this->emu().read_stack_pointer();
uint64_t return_address{};
this->emu().try_read_memory(rsp, &return_address, sizeof(return_address));
const auto* mod_name = this->mod_manager.find_name(return_address);
log.print(is_interesting_call ? color::yellow : color::dark_gray,
"Executing function: %s - %s (0x%" PRIx64 ") via (0x%" PRIx64 ") %s\n", binary->name.c_str(),
export_entry->second.c_str(), address, return_address, mod_name);
}
else if (address == binary->entry_point)
{
log.print(is_interesting_call ? color::yellow : color::gray, "Executing entry point: %s (0x%" PRIx64 ")\n",
binary->name.c_str(), address);
}
}
if (!this->verbose)
{
return;
}
auto& emu = this->emu();
// TODO: Remove or cleanup
log.print(color::gray,
"Inst: %16" PRIx64 " - RAX: %16" PRIx64 " - RBX: %16" PRIx64 " - RCX: %16" PRIx64 " - RDX: %16" PRIx64
" - R8: %16" PRIx64 " - R9: %16" PRIx64 " - RDI: %16" PRIx64 " - RSI: %16" PRIx64 " - %s\n",
address, emu.reg(x64_register::rax), emu.reg(x64_register::rbx), emu.reg(x64_register::rcx),
emu.reg(x64_register::rdx), emu.reg(x64_register::r8), emu.reg(x64_register::r9),
emu.reg(x64_register::rdi), emu.reg(x64_register::rsi), binary ? binary->name.c_str() : "<N/A>");
}
void windows_emulator::setup_hooks()
{
this->emu().hook_instruction(x64_hookable_instructions::syscall, [&] {
for (const auto& hook : this->syscall_hooks_)
{
if (hook() == instruction_hook_continuation::skip_instruction)
{
return instruction_hook_continuation::skip_instruction;
}
}
this->dispatcher.dispatch(*this);
return instruction_hook_continuation::skip_instruction;
});
this->emu().hook_instruction(x64_hookable_instructions::rdtsc, [&] {
const auto instructions = this->process.executed_instructions;
this->emu().reg(x64_register::rax, instructions & 0xFFFFFFFF);
this->emu().reg(x64_register::rdx, (instructions >> 32) & 0xFFFFFFFF);
return instruction_hook_continuation::skip_instruction;
});
this->emu().hook_instruction(x64_hookable_instructions::invalid, [&] {
const auto ip = this->emu().read_instruction_pointer();
this->log.print(color::gray, "Invalid instruction at: 0x%" PRIx64 "\n", ip);
return instruction_hook_continuation::skip_instruction;
});
this->emu().hook_interrupt([&](const int interrupt) {
const auto rip = this->emu().read_instruction_pointer();
switch (interrupt)
{
case 0:
dispatch_integer_division_by_zero(this->emu(), this->process);
return;
case 1:
this->log.print(color::pink, "Singlestep: 0x%" PRIx64 "\n", rip);
dispatch_single_step(this->emu(), this->process);
return;
case 6:
dispatch_illegal_instruction_violation(this->emu(), this->process);
return;
default:
break;
}
this->log.print(color::gray, "Interrupt: %i 0x%" PRIx64 "\n", interrupt, rip);
if (this->fuzzing || true) // TODO: Fix
{
this->process.exception_rip = rip;
this->emu().stop();
}
});
this->emu().hook_memory_violation([&](const uint64_t address, const size_t size, const memory_operation operation,
const memory_violation_type type) {
const auto permission = get_permission_string(operation);
const auto ip = this->emu().read_instruction_pointer();
const char* name = this->mod_manager.find_name(ip);
if (type == memory_violation_type::protection)
{
this->log.print(color::gray, "Protection violation: 0x%" PRIx64 " (%zX) - %s at 0x%" PRIx64 " (%s)\n",
address, size, permission.c_str(), ip, name);
}
else if (type == memory_violation_type::unmapped)
{
this->log.print(color::gray, "Mapping violation: 0x%" PRIx64 " (%zX) - %s at 0x%" PRIx64 " (%s)\n", address,
size, permission.c_str(), ip, name);
}
if (this->fuzzing)
{
this->process.exception_rip = ip;
this->emu().stop();
return memory_violation_continuation::stop;
}
dispatch_access_violation(this->emu(), this->process, address, operation);
return memory_violation_continuation::resume;
});
this->emu().hook_memory_execution(
0, std::numeric_limits<size_t>::max(),
[&](const uint64_t address, const size_t, const uint64_t) { this->on_instruction_execution(address); });
}
void windows_emulator::start(std::chrono::nanoseconds timeout, size_t count)
{
const auto use_count = count > 0;
const auto use_timeout = timeout != std::chrono::nanoseconds{};
const auto start_time = std::chrono::high_resolution_clock::now();
const auto start_instructions = this->process.executed_instructions;
const auto target_time = start_time + timeout;
const auto target_instructions = start_instructions + count;
while (true)
{
if (this->switch_thread_ || !this->current_thread().is_thread_ready(this->process))
{
this->perform_thread_switch();
}
this->emu().start_from_ip(timeout, count);
if (!this->switch_thread_ && !this->emu().has_violation())
{
break;
}
if (use_timeout)
{
const auto now = std::chrono::high_resolution_clock::now();
if (now >= target_time)
{
break;
}
timeout = target_time - now;
}
if (use_count)
{
const auto current_instructions = this->process.executed_instructions;
if (current_instructions >= target_instructions)
{
break;
}
count = target_instructions - current_instructions;
}
}
}
void windows_emulator::serialize(utils::buffer_serializer& buffer) const
{
buffer.write(this->switch_thread_);
buffer.write(this->use_relative_time_);
this->emu().serialize_state(buffer, false);
this->memory.serialize_memory_state(buffer, false);
this->mod_manager.serialize(buffer);
this->process.serialize(buffer);
this->dispatcher.serialize(buffer);
}
void windows_emulator::deserialize(utils::buffer_deserializer& buffer)
{
buffer.register_factory<memory_manager_wrapper>([this] {
return memory_manager_wrapper{this->memory}; //
});
buffer.register_factory<module_manager_wrapper>([this] {
return module_manager_wrapper{this->mod_manager}; //
});
buffer.register_factory<x64_emulator_wrapper>([this] {
return x64_emulator_wrapper{this->emu()}; //
});
buffer.register_factory<windows_emulator_wrapper>([this] {
return windows_emulator_wrapper{*this}; //
});
buffer.read(this->switch_thread_);
buffer.read(this->use_relative_time_);
this->memory.unmap_all_memory();
this->emu().deserialize_state(buffer, false);
this->memory.deserialize_memory_state(buffer, false);
this->mod_manager.deserialize(buffer);
this->process.deserialize(buffer);
this->dispatcher.deserialize(buffer);
}
void windows_emulator::save_snapshot()
{
throw std::runtime_error("Not supported");
/*utils::buffer_serializer serializer{};
this->emu().serialize_state(serializer, true);
this->memory.serialize_memory_state(serializer, true);
this->mod_manager.serialize(serializer);
this->process.serialize(serializer);
this->process_snapshot_ = serializer.move_buffer();
// TODO: Make process copyable
// this->process_snapshot_ = this->process;*/
}
void windows_emulator::restore_snapshot()
{
throw std::runtime_error("Not supported");
/*if (this->process_snapshot_.empty())
{
assert(false);
return;
}
utils::buffer_deserializer deserializer{this->process_snapshot_};
this->emu().deserialize_state(deserializer, true);
this->memory.deserialize_memory_state(deserializer, true);
this->mod_manager.deserialize(deserializer);
this->process.deserialize(deserializer);
// this->process = *this->process_snapshot_;*/
}