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@ -172,6 +172,7 @@ void emu_t::extract_branch_data() {
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br1 += m_vm->m_module_base;
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br2 += m_vm->m_module_base;
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// We need to handle the case that the jump points to another jump
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auto br1_legit = legit_branch(*cc_blk, br1);
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auto br2_legit = legit_branch(*cc_blk, br2);
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std::printf("> br1 legit: %d, br2 legit: %d\n", br1_legit, br2_legit);
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@ -269,19 +270,10 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
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}
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if (instr.mnemonic == ZYDIS_MNEMONIC_INVALID) return false;
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uc_context* ctx;
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uct_context_alloc(uc, &ctx);
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uc_context_save(uc, ctx);
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// if this is the first instruction of this handler then save the stack...
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if (!obj->cc_trace.m_instrs.size()) {
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obj->cc_trace.m_vip = obj->cc_blk->m_vm.vip;
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obj->cc_trace.m_vsp = obj->cc_blk->m_vm.vsp;
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obj->cc_trace.m_stack = new std::uint8_t[STACK_SIZE]; g_new_delete_tracker++;
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uc_mem_read(uc, STACK_BASE, obj->cc_trace.m_stack, STACK_SIZE);
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}
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obj->cc_trace.m_instrs.push_back({instr, ctx});
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// RET or JMP REG means the end of a vm handler...
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@ -292,7 +284,7 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
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// makes it easier for profiles to be correct...
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vm::instrs::deobfuscate(obj->cc_trace);
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// find the last MOV REG, DWORD PTR [VIP] in the instruction stream, then
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/* // find the last MOV REG, DWORD PTR [VIP] in the instruction stream, then
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// remove any instructions from this instruction to the JMP/RET...
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const auto rva_fetch = std::find_if(
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obj->cc_trace.m_instrs.rbegin(), obj->cc_trace.m_instrs.rend(),
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@ -303,7 +295,7 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
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i.operands[0].type == ZYDIS_OPERAND_TYPE_REGISTER &&
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i.operands[1].type == ZYDIS_OPERAND_TYPE_MEMORY &&
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i.operands[1].mem.base == vip && i.operands[1].size == 32;
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});
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});
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if (rva_fetch != obj->cc_trace.m_instrs.rend())
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{
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@ -313,17 +305,16 @@ bool emu_t::branch_pred_spec_exec(uc_engine* uc, uint64_t address,
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}
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obj->cc_trace.m_instrs.erase((rva_fetch + 1).base(),
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obj->cc_trace.m_instrs.end());
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}
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} */
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const auto vinstr = vm::instrs::determine(obj->cc_trace);
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// -- free the trace since we will start a new one...
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std::for_each(obj->cc_trace.m_instrs.begin(), obj->cc_trace.m_instrs.end(),
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[&](const vm::instrs::emu_instr_t& instr) {
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uct_context_free(instr.m_cpu);
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});
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delete[] obj->cc_trace.m_stack; if (obj->cc_trace.m_stack) g_new_delete_tracker--;
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obj->cc_trace.m_instrs.clear();
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if (vinstr.mnemonic != vm::instrs::mnemonic_t::jmp) {
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@ -565,6 +556,10 @@ bool emu_t::legit_branch(vm::instrs::vblk_t& vblk, std::uintptr_t branch_addr) {
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uc_reg_read(uc, UC_X86_REG_RIP, &rip);
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uc_reg_read(uc, vm::instrs::reg_map[vblk.m_vm.vsp], &vsp);
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uc_mem_write(uc, vsp, &branch_addr, sizeof branch_addr);
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// reset vsp and vip to their pre-jmp status in the current code trace
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// this will be reset when the jmp instruction is emulated again
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cc_trace.m_vsp = cc_blk->m_vm.vsp, cc_trace.m_vip = cc_blk->m_vm.vip;
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m_sreg_cnt = 0u;
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uc_emu_start(uc, rip, 0ull, 0ull, 0ull);
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@ -606,31 +601,37 @@ std::optional<std::pair<std::uintptr_t, std::uintptr_t>> emu_t::could_have_jcc(
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return v.mnemonic == vm::instrs::mnemonic_t::lconst && v.imm.size == 64;
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};
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const auto lconst1 =
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std::find_if(vinstrs.rbegin(), vinstrs.rend(), lconst64_chk);
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if (lconst1 == vinstrs.rend()) return {};
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const auto lconst2 = std::find_if(lconst1 + 1, vinstrs.rend(), lconst64_chk);
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static const auto valid_mem = [=](uintptr_t loc)
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{
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// check to see if the imm val is inside of the image...
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if (loc > m_vm->m_image_base + m_vm->m_image_size ||
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loc < m_vm->m_image_base ||
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loc > m_vm->m_image_base + m_vm->m_image_size ||
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loc < m_vm->m_image_base)
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return false;
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// check to see if the imm's points to something inside of an executable
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// section...
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if (!vm::utils::scn::executable(
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m_vm->m_module_base,
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(loc - m_vm->m_image_base) + m_vm->m_module_base))
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return false;
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return true;
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};
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auto lconst1 = vinstrs.rbegin();
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do {
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lconst1 =
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std::find_if(lconst1 + 1, vinstrs.rend(), lconst64_chk);
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if (lconst1 == vinstrs.rend()) return {};
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} while (!valid_mem(lconst1->imm.val));
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auto lconst2 = lconst1;
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do {
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lconst2 =
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std::find_if(lconst2 + 1, vinstrs.rend(), lconst64_chk);
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if (lconst2 == vinstrs.rend()) return {};
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// check to see if the imm val is inside of the image...
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if (lconst1->imm.val > m_vm->m_image_base + m_vm->m_image_size ||
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lconst1->imm.val < m_vm->m_image_base ||
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lconst2->imm.val > m_vm->m_image_base + m_vm->m_image_size ||
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lconst2->imm.val < m_vm->m_image_base)
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return {};
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// check to see if the imm's points to something inside of an executable
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// section...
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if (!vm::utils::scn::executable(
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m_vm->m_module_base,
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(lconst1->imm.val - m_vm->m_image_base) + m_vm->m_module_base) ||
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!vm::utils::scn::executable(
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m_vm->m_module_base,
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(lconst2->imm.val - m_vm->m_image_base) + m_vm->m_module_base))
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return {};
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} while (!valid_mem(lconst1->imm.val));
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return {{lconst1->imm.val, lconst2->imm.val}};
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}
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