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246 lines
9.6 KiB
246 lines
9.6 KiB
#include "vmemu_t.hpp"
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namespace vm
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{
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emu_t::emu_t( std::uint32_t vm_entry_rva, std::uintptr_t image_base, std::uintptr_t module_base )
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: module_base( module_base ), image_base( image_base ), vm_entry_rva( vm_entry_rva ), uc( nullptr ),
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code_blocks( nullptr ), vmctx( new vm::ctx_t( module_base, image_base, vm_entry_rva ) )
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{
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}
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bool emu_t::init()
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{
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uc_err err;
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std::uintptr_t stack_base = 0x1000000;
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std::uintptr_t stack_addr = ( stack_base + ( 0x1000 * 20 ) ) - 0x6000;
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const auto rip = module_base + vm_entry_rva;
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const auto image_size = NT_HEADER( module_base )->OptionalHeader.SizeOfImage;
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if ( ( err = uc_open( UC_ARCH_X86, UC_MODE_64, &uc ) ) )
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{
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std::printf( "failed on uc_mem_map() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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if ( ( err = uc_mem_map( uc, module_base, image_size, UC_PROT_ALL ) ) )
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{
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std::printf( "failed on uc_mem_map() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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if ( ( err = uc_mem_map( uc, 0x1000000, 0x1000 * 20, UC_PROT_ALL ) ) )
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{
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std::printf( "failed on uc_mem_map() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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if ( ( err = uc_mem_write( uc, module_base, reinterpret_cast< void * >( module_base ), image_size ) ) )
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{
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std::printf( "failed on uc_mem_write() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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if ( ( err = uc_reg_write( uc, UC_X86_REG_RIP, &rip ) ) )
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{
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std::printf( "failed on uc_reg_write() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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if ( ( err = uc_reg_write( uc, UC_X86_REG_RSP, &stack_addr ) ) )
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{
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std::printf( "failed on uc_reg_write() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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if ( ( err = uc_hook_add( uc, &trace, UC_HOOK_CODE, &vm::emu_t::hook_code, this, module_base,
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module_base + image_size ) ) )
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{
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std::printf( "failed on uc_hook_add() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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if ( ( err = uc_hook_add( uc, &trace1, UC_HOOK_MEM_READ_UNMAPPED | UC_HOOK_MEM_WRITE_UNMAPPED,
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vm::emu_t::hook_mem_invalid, this, 1, 0 ) ) )
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{
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std::printf( "failed on uc_hook_add() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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return true;
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}
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emu_t::~emu_t()
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{
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if ( uc )
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uc_close( uc );
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delete vmctx;
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}
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bool emu_t::get_trace( std::vector< vm::instrs::code_block_t > &entries )
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{
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// hook_code will fill this vector up with values...
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code_blocks = &entries;
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uc_err err;
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if ( ( err = uc_emu_start( uc, vm_entry_rva + module_base, NULL, NULL, NULL ) ) )
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{
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std::printf( "failed on uc_emu_start() with error returned %u: %s\n", err, uc_strerror( err ) );
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return false;
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}
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return true;
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}
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uc_err emu_t::create_entry( vmp2::v2::entry_t *entry )
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{
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uc_reg_read( uc, UC_X86_REG_R15, &entry->regs.r15 );
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uc_reg_read( uc, UC_X86_REG_R14, &entry->regs.r14 );
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uc_reg_read( uc, UC_X86_REG_R13, &entry->regs.r13 );
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uc_reg_read( uc, UC_X86_REG_R12, &entry->regs.r12 );
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uc_reg_read( uc, UC_X86_REG_R11, &entry->regs.r11 );
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uc_reg_read( uc, UC_X86_REG_R10, &entry->regs.r10 );
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uc_reg_read( uc, UC_X86_REG_R9, &entry->regs.r9 );
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uc_reg_read( uc, UC_X86_REG_R8, &entry->regs.r8 );
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uc_reg_read( uc, UC_X86_REG_RBP, &entry->regs.rbp );
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uc_reg_read( uc, UC_X86_REG_RDI, &entry->regs.rdi );
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uc_reg_read( uc, UC_X86_REG_RSI, &entry->regs.rsi );
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uc_reg_read( uc, UC_X86_REG_RDX, &entry->regs.rdx );
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uc_reg_read( uc, UC_X86_REG_RCX, &entry->regs.rcx );
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uc_reg_read( uc, UC_X86_REG_RBX, &entry->regs.rbx );
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uc_reg_read( uc, UC_X86_REG_RAX, &entry->regs.rax );
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uc_reg_read( uc, UC_X86_REG_EFLAGS, &entry->regs.rflags );
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entry->vip = entry->regs.rsi;
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entry->handler_idx = entry->regs.rax;
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entry->decrypt_key = entry->regs.rbx;
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uc_err err;
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if ( ( err = uc_mem_read( uc, entry->regs.rdi, entry->vregs.raw, sizeof entry->vregs.raw ) ) )
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return err;
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// copy virtual stack values...
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for ( auto idx = 0u; idx < sizeof( entry->vsp ) / 8; ++idx )
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if ( ( err = uc_mem_read( uc, entry->regs.rbp + ( idx * 8 ), &entry->vsp.qword[ idx ],
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sizeof entry->vsp.qword[ idx ] ) ) )
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return err;
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return UC_ERR_OK;
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}
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void emu_t::hook_code( uc_engine *uc, uint64_t address, uint32_t size, vm::emu_t *obj )
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{
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std::printf( ">>> Tracing instruction at 0x%p, instruction size = 0x%x\n", address, size );
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// grab JMP RDX/RCX <-- this register...
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static const auto jmp_reg = obj->vmctx->vm_entry[ obj->vmctx->vm_entry.size() ].instr.operands[ 0 ].reg.value;
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static ZydisDecoder decoder;
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static ZydisDecodedInstruction instr;
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static std::uintptr_t reg_val = 0u;
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// init zydis decoder only a single time...
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if ( static std::atomic< bool > once = true; once.exchange( false ) )
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ZydisDecoderInit( &decoder, ZYDIS_MACHINE_MODE_LONG_64, ZYDIS_ADDRESS_WIDTH_64 );
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if ( ZYAN_SUCCESS(
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ZydisDecoderDecodeBuffer( &decoder, reinterpret_cast< void * >( address ), size, &instr ) ) &&
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instr.mnemonic == ZYDIS_MNEMONIC_JMP && instr.operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER &&
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instr.operands[ 0 ].reg.value == jmp_reg )
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{
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uc_err err;
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vmp2::v2::entry_t new_entry;
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std::optional< vm::instrs::virt_instr_t > virt_instr;
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vm::handler::profile_t *vm_handler_profile = nullptr;
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switch ( jmp_reg )
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{
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case ZYDIS_REGISTER_RDX:
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uc_reg_read( uc, UC_X86_REG_RDX, ®_val );
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break;
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case ZYDIS_REGISTER_RCX:
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uc_reg_read( uc, UC_X86_REG_RCX, ®_val );
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break;
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default:
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std::printf( "[!] invalid jump register... = %d\n", jmp_reg );
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exit( 0 );
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}
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// checks to see if the address
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// in JMP RDX/RCX is a vm handler address...
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static const auto vm_handler_check = [ & ]( const vm::handler::handler_t &vm_handler ) -> bool {
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return vm_handler.address == reg_val;
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};
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if ( std::find_if( obj->vmctx->vm_handlers.begin(), obj->vmctx->vm_handlers.end(), vm_handler_check ) ==
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obj->vmctx->vm_handlers.end() )
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return;
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if ( ( err = obj->create_entry( &new_entry ) ) )
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{
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std::printf( "[!] failed to create new entry... reason = %u, %s\n", err, uc_strerror( err ) );
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exit( 0 );
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}
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// the first virtual instruction we are going to create the first code_block_t...
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if ( static std::atomic< bool > once = true; once.exchange( false ) )
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if ( obj->code_blocks->empty() )
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obj->code_blocks->push_back( vm::instrs::code_block_t{ new_entry.vip } );
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if ( virt_instr = vm::instrs::get( *obj->vmctx, new_entry ); !virt_instr.has_value() )
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{
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std::printf( "[!] failed to create vm::instrs::virt_instr_t...\n" );
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exit( 0 );
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}
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obj->code_blocks->back().vinstrs.push_back( virt_instr.value() );
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// if there is a virtual JMP instruction then we need to create a new code_block_t...
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if ( ( vm_handler_profile = obj->vmctx->vm_handlers[ new_entry.handler_idx ].profile ) &&
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vm_handler_profile->mnemonic == vm::handler::mnemonic_t::JMP )
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{
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const auto code_block_address =
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vm::instrs::code_block_addr( *obj->vmctx, new_entry, obj->image_base, obj->module_base );
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// set the next code block up...
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obj->code_blocks->push_back( vm::instrs::code_block_t{ code_block_address } );
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}
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}
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else if ( instr.mnemonic == ZYDIS_MNEMONIC_RET ) // finish tracing...
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{
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uc_emu_stop( uc );
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}
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}
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bool emu_t::hook_mem_invalid( uc_engine *uc, uc_mem_type type, uint64_t address, int size, int64_t value,
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vm::emu_t *obj )
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{
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uc_err err;
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if ( ( err = uc_mem_map( obj->uc, address & ~0xFFFull, 0x1000, UC_PROT_ALL ) ) )
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std::printf( "failed on uc_mem_map() with error returned %u: %s\n", err, uc_strerror( err ) );
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switch ( type )
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{
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case UC_MEM_WRITE_UNMAPPED:
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printf( ">>> Missing memory is being WRITE at 0x%p, data size = %u, data value = 0x%p\n", address, size,
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value );
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return true;
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case UC_MEM_READ_UNMAPPED:
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printf( ">>> Missing memory is being READ at 0x%p, data size = %u, data value = 0x%p\n", address, size,
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value );
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return true;
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default:
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printf( ">>> Missing memory at 0x%p, data size = %u, data value = 0x%p\n", address, size, value );
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return true;
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}
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}
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} // namespace vm
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