fixed crashing when trying to emulate vmentry on packed bins...

merge-requests/5/merge
_xeroxz 3 years ago
parent bf2552c1f6
commit ede70ec582

@ -89,9 +89,6 @@ namespace vm
{
std::printf( "failed on uc_emu_start() with error returned %u: %s\n", err, uc_strerror( err ) );
for ( auto &[ code_block, uc_code_block_context ] : code_blocks )
entries.push_back( code_block );
return false;
}
@ -208,7 +205,8 @@ namespace vm
void emu_t::hook_code( uc_engine *uc, uint64_t address, uint32_t size, vm::emu_t *obj )
{
std::printf( ">>> Tracing instruction at 0x%p, instruction size = 0x%x\n", address, size );
// std::printf( ">>> Tracing instruction at 0x%p, instruction size = 0x%x\n",
//( address - obj->vmctx->module_base ) + obj->vmctx->image_base, size );
// bad code... but i need to skip JMP instructions when tracing branches since i save context
// on the jmp instruction... so it needs to be skipped...
@ -223,7 +221,7 @@ namespace vm
static ZydisDecoder decoder;
static ZydisDecodedInstruction instr;
static std::uintptr_t reg_val = 0u;
static std::uintptr_t reg_val = 0u, rsi = 0u;
// init zydis decoder only a single time...
if ( static std::atomic< bool > once = true; once.exchange( false ) )
@ -281,6 +279,13 @@ namespace vm
}
obj->code_blocks.back().first.vinstrs.push_back( virt_instr.value() );
uc_reg_read( obj->uc, UC_X86_REG_RSI, &rsi );
std::printf( "> %s handler = 0x%p vip = 0x%p\n",
obj->vmctx->vm_handlers[ new_entry.handler_idx ].profile
? obj->vmctx->vm_handlers[ new_entry.handler_idx ].profile->name
: "UNK",
( reg_val - obj->vmctx->module_base ) + obj->vmctx->image_base,
( rsi - obj->vmctx->module_base ) + obj->vmctx->image_base );
// if there is a virtual JMP instruction then we need to grab jcc data for the current code_block_t
// and then create a new code_block_t...
@ -289,8 +294,16 @@ namespace vm
{
const auto code_block_address = vm::instrs::code_block_addr( *obj->vmctx, new_entry );
auto jcc = vm::instrs::get_jcc_data( *obj->vmctx, obj->code_blocks.back().first );
if ( jcc.has_value() )
{
obj->code_blocks.back().first.jcc = jcc.value();
}
else // the branch(s) dont start with SREGQ... stopping...
{
uc_emu_stop( uc );
return;
}
// save cpu state as well as stack...
obj->code_blocks.back().second = std::make_shared< cpu_ctx >();
@ -336,6 +349,11 @@ namespace vm
// vmexit's cannot have a branch...
obj->code_blocks.back().first.jcc.has_jcc = false;
}
else if ( instr.mnemonic == ZYDIS_MNEMONIC_CALL && instr.operands[ 0 ].type == ZYDIS_OPERAND_TYPE_REGISTER )
{
const auto rip = address + instr.length;
uc_reg_write( obj->uc, UC_X86_REG_RIP, &rip );
}
}
bool emu_t::hook_mem_invalid( uc_engine *uc, uc_mem_type type, uint64_t address, int size, int64_t value,

@ -16,7 +16,7 @@ namespace vm
struct cpu_ctx
{
uc_context *context;
std::uint8_t stack[ PAGE_4K * 20 ];
std::uint8_t stack[ PAGE_4K * 100 ];
};
class emu_t

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