still working on branch detection and emulation

pull/1/head
xtremegamer1 2 years ago
parent 97908a1e33
commit 6cf93a5fcb

2
deps/vmprofiler vendored

@ -1 +1 @@
Subproject commit 80b5c20795aa18bd5a46b813b4c8207e3a7c79ce
Subproject commit 1516e2a2783308b778109659cce62ea2d78e4c82

@ -26,7 +26,7 @@ class emu_t {
~emu_t();
bool init();
bool emulate(std::uint32_t vmenter_rva, vm::instrs::vrtn_t& vrtn);
const bool m_log_instructions = false;
const bool m_log_instructions = true;
private:
uc_engine* uc;

@ -269,11 +269,13 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
return false;
}
if (instr.mnemonic == ZYDIS_MNEMONIC_INVALID) return false;
if (instr.mnemonic == ZYDIS_MNEMONIC_INVALID) {std::printf("> bad instruction\n"); return false;}
uc_context* ctx;
uct_context_alloc(uc, &ctx);
uc_context_save(uc, ctx);
if (obj->cc_trace.m_instrs.empty())
obj->cc_trace.m_begin = address;
obj->cc_trace.m_instrs.push_back({instr, ctx});
// RET or JMP REG means the end of a vm handler...
@ -283,7 +285,15 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
// deobfuscate the instruction stream before profiling...
// makes it easier for profiles to be correct...
vm::instrs::deobfuscate(obj->cc_trace);
std::printf("> vsp = %s, vip = %s, address = %p (%p)\n", ZydisRegisterGetString(obj->cc_trace.m_vsp), ZydisRegisterGetString(obj->cc_trace.m_vip),
obj->cc_trace.m_begin, obj->cc_trace.m_begin - obj->m_vm->m_module_base + obj->m_vm->m_image_base);
zydis_rtn_t inst_stream;
std::for_each(obj->cc_trace.m_instrs.begin(),
obj->cc_trace.m_instrs.end(),
[&](vm::instrs::emu_instr_t& instr) {
inst_stream.push_back({instr.m_instr});
});
vm::utils::print(inst_stream);
/* // find the last MOV REG, DWORD PTR [VIP] in the instruction stream, then
// remove any instructions from this instruction to the JMP/RET...
const auto rva_fetch = std::find_if(
@ -308,7 +318,7 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
} */
const auto vinstr = vm::instrs::determine(obj->cc_trace);
std::printf("instruction is: %d\n", vinstr.mnemonic);
// -- free the trace since we will start a new one...
std::for_each(obj->cc_trace.m_instrs.begin(), obj->cc_trace.m_instrs.end(),
[&](const vm::instrs::emu_instr_t& instr) {
@ -318,13 +328,16 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
obj->cc_trace.m_instrs.clear();
if (vinstr.mnemonic != vm::instrs::mnemonic_t::jmp) {
if (vinstr.mnemonic != vm::instrs::mnemonic_t::sreg) uc_emu_stop(uc);
/* if (vinstr.mnemonic != vm::instrs::mnemonic_t::sreg) uc_emu_stop(uc);
if (!vinstr.imm.has_imm) uc_emu_stop(uc);
if (vinstr.imm.size != 8 || vinstr.imm.val > 8 * VIRTUAL_REGISTER_COUNT)
uc_emu_stop(uc);
uc_emu_stop(uc); */
// stop if done or if instruction is invalid
if (vinstr.mnemonic == instrs::mnemonic_t::unknown)
uc_emu_stop(uc);
// -- stop after 10 legit SREG's...
if (++obj->m_sreg_cnt == 10) uc_emu_stop(uc);
}
@ -608,14 +621,7 @@ std::optional<std::pair<std::uintptr_t, std::uintptr_t>> emu_t::could_have_jcc(
loc > m_vm->m_image_base + m_vm->m_image_size ||
loc < m_vm->m_image_base)
return false;
// check to see if the imm's points to something inside of an executable
// section...
if (!vm::utils::scn::executable(
m_vm->m_module_base,
(loc - m_vm->m_image_base) + m_vm->m_module_base))
return false;
return true;
return true;
};
auto lconst1 = vinstrs.rbegin();
@ -632,6 +638,8 @@ std::optional<std::pair<std::uintptr_t, std::uintptr_t>> emu_t::could_have_jcc(
if (lconst2 == vinstrs.rend()) return {};
} while (!valid_mem(lconst1->imm.val));
std::printf("possible jcc: %p, %p\n", lconst1->imm.val, lconst2->imm.val);
return {{lconst1->imm.val, lconst2->imm.val}};
}
} // namespace vm
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