forked from vmp3/vmprofiler
to make an std::map<zydis_reg_t, unicorn_register>...master
John Doe
3 years ago
parent
79c3695828
commit
eb91191526
@ -0,0 +1,163 @@
|
||||
#include <vminstrs.hpp>
|
||||
|
||||
namespace vm::instrs {
|
||||
void deobfuscate(hndlr_trace_t& trace) {
|
||||
static const auto _uses_reg = [](zydis_decoded_operand_t& op,
|
||||
zydis_reg_t reg) -> bool {
|
||||
switch (op.type) {
|
||||
case ZYDIS_OPERAND_TYPE_MEMORY: {
|
||||
return vm::utils::reg::compare(op.mem.base, reg) ||
|
||||
vm::utils::reg::compare(op.mem.index, reg);
|
||||
}
|
||||
case ZYDIS_OPERAND_TYPE_REGISTER: {
|
||||
return vm::utils::reg::compare(op.reg.value, reg);
|
||||
}
|
||||
default:
|
||||
break;
|
||||
}
|
||||
return false;
|
||||
};
|
||||
|
||||
static const auto _reads = [](zydis_decoded_instr_t& instr,
|
||||
zydis_reg_t reg) -> bool {
|
||||
if (instr.operands[0].type == ZYDIS_OPERAND_TYPE_MEMORY &&
|
||||
vm::utils::reg::compare(instr.operands[0].mem.base, reg))
|
||||
return true;
|
||||
|
||||
for (auto op_idx = 0u; op_idx < instr.operand_count; ++op_idx)
|
||||
if (instr.operands[op_idx].actions & ZYDIS_OPERAND_ACTION_READ &&
|
||||
_uses_reg(instr.operands[op_idx], reg))
|
||||
return true;
|
||||
return false;
|
||||
};
|
||||
|
||||
static const auto _writes = [](zydis_decoded_instr_t& instr,
|
||||
zydis_reg_t reg) -> bool {
|
||||
for (auto op_idx = 0u; op_idx < instr.operand_count; ++op_idx)
|
||||
// if instruction writes to the specific register...
|
||||
if (instr.operands[op_idx].type == ZYDIS_OPERAND_TYPE_REGISTER &&
|
||||
instr.operands[op_idx].actions & ZYDIS_OPERAND_ACTION_WRITE &&
|
||||
!(instr.operands[op_idx].actions & ZYDIS_OPERAND_ACTION_READ) &&
|
||||
vm::utils::reg::compare(instr.operands[op_idx].reg.value, reg))
|
||||
return true;
|
||||
return false;
|
||||
};
|
||||
|
||||
std::uint32_t last_size = 0u;
|
||||
static const std::vector<ZydisMnemonic> blacklist = {
|
||||
ZYDIS_MNEMONIC_CLC, ZYDIS_MNEMONIC_BT, ZYDIS_MNEMONIC_TEST,
|
||||
ZYDIS_MNEMONIC_CMP, ZYDIS_MNEMONIC_CMC, ZYDIS_MNEMONIC_STC};
|
||||
|
||||
static const std::vector<ZydisMnemonic> whitelist = {
|
||||
ZYDIS_MNEMONIC_PUSH, ZYDIS_MNEMONIC_POP, ZYDIS_MNEMONIC_CALL,
|
||||
ZYDIS_MNEMONIC_DIV};
|
||||
|
||||
do {
|
||||
last_size = trace.m_instrs.size();
|
||||
for (auto itr = trace.m_instrs.begin(); itr != trace.m_instrs.end();
|
||||
++itr) {
|
||||
if (std::find(whitelist.begin(), whitelist.end(),
|
||||
itr->m_instr.mnemonic) != whitelist.end())
|
||||
continue;
|
||||
|
||||
if (std::find(blacklist.begin(), blacklist.end(),
|
||||
itr->m_instr.mnemonic) != blacklist.end()) {
|
||||
trace.m_instrs.erase(itr);
|
||||
break;
|
||||
}
|
||||
|
||||
if (vm::utils::is_jmp(itr->m_instr)) {
|
||||
trace.m_instrs.erase(itr);
|
||||
break;
|
||||
}
|
||||
|
||||
zydis_reg_t reg = ZYDIS_REGISTER_NONE;
|
||||
// look for operands with writes to a register...
|
||||
for (auto op_idx = 0u; op_idx < itr->m_instr.operand_count; ++op_idx)
|
||||
if (itr->m_instr.operands[op_idx].type == ZYDIS_OPERAND_TYPE_REGISTER &&
|
||||
itr->m_instr.operands[op_idx].actions & ZYDIS_OPERAND_ACTION_WRITE)
|
||||
reg = vm::utils::reg::to64(itr->m_instr.operands[0].reg.value);
|
||||
|
||||
// if this current instruction writes to a register, look ahead in the
|
||||
// instruction stream to see if it gets written too before it gets read...
|
||||
if (reg != ZYDIS_REGISTER_NONE) {
|
||||
// find the next place that this register is written too...
|
||||
auto write_result = std::find_if(itr + 1, trace.m_instrs.end(),
|
||||
[&](emu_instr_t& instr) -> bool {
|
||||
return _writes(instr.m_instr, reg);
|
||||
});
|
||||
|
||||
auto read_result = std::find_if(itr + 1, write_result,
|
||||
[&](emu_instr_t& instr) -> bool {
|
||||
return _reads(instr.m_instr, reg);
|
||||
});
|
||||
|
||||
// if there is neither a read or a write to this register in the
|
||||
// instruction stream then we are going to be safe and leave the
|
||||
// instruction in the stream...
|
||||
if (read_result == trace.m_instrs.end() &&
|
||||
write_result == trace.m_instrs.end())
|
||||
continue;
|
||||
|
||||
// if there is no read of the register before the next write... and
|
||||
// there is a known next write, then remove the instruction from the
|
||||
// stream...
|
||||
if (read_result == write_result &&
|
||||
write_result != trace.m_instrs.end()) {
|
||||
// if the instruction reads and writes the same register than skip...
|
||||
if (_reads(read_result->m_instr, reg) &&
|
||||
_writes(read_result->m_instr, reg))
|
||||
continue;
|
||||
|
||||
trace.m_instrs.erase(itr);
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
} while (last_size != trace.m_instrs.size());
|
||||
}
|
||||
|
||||
void init() {
|
||||
if (static std::atomic_bool once = true; once.exchange(false))
|
||||
std::sort(profiles.begin(), profiles.end(),
|
||||
[&](profiler_t* a, profiler_t* b) -> bool {
|
||||
return a->matchers.size() > b->matchers.size();
|
||||
});
|
||||
}
|
||||
|
||||
vinstr_t determine(zydis_reg_t& vip, zydis_reg_t& vsp, hndlr_trace_t& hndlr) {
|
||||
const auto& instrs = hndlr.m_instrs;
|
||||
const auto profile = std::find_if(
|
||||
profiles.begin(), profiles.end(), [&](profiler_t* profile) -> bool {
|
||||
for (auto& matcher : profile->matchers) {
|
||||
const auto matched =
|
||||
std::find_if(instrs.begin(), instrs.end(),
|
||||
[&](const emu_instr_t& instr) -> bool {
|
||||
const auto& i = instr.m_instr;
|
||||
return matcher(vip, vsp, i);
|
||||
});
|
||||
if (matched == instrs.end())
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
});
|
||||
|
||||
if (profile == profiles.end())
|
||||
return vinstr_t{mnemonic_t::unknown};
|
||||
|
||||
auto result = (*profile)->generate(vip, vsp, hndlr);
|
||||
return result.has_value() ? result.value() : vinstr_t{mnemonic_t::unknown};
|
||||
}
|
||||
|
||||
profiler_t* get_profile(mnemonic_t mnemonic) {
|
||||
if (mnemonic == mnemonic_t::unknown)
|
||||
return nullptr;
|
||||
|
||||
const auto res = std::find_if(profiles.begin(), profiles.end(),
|
||||
[&](profiler_t* profile) -> bool {
|
||||
return profile->mnemonic == mnemonic;
|
||||
});
|
||||
|
||||
return res == profiles.end() ? nullptr : *res;
|
||||
}
|
||||
} // namespace vm::instrs
|
||||
Loading…
Reference in new issue