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x64dbg/x64_dbg_dbg/disasm_helper.cpp

397 lines
10 KiB
C++

/**
@file disasm_helper.cpp
@brief Implements the disasm helper class.
*/
#include "disasm_helper.h"
#include "value.h"
#include "console.h"
#include "debugger.h"
#include "memory.h"
#include <cwctype>
#include <cwchar>
#include "capstone_wrapper.h"
uint disasmback(unsigned char* data, uint base, uint size, uint ip, int n)
{
int i;
uint abuf[131], addr, back, cmdsize;
unsigned char* pdata;
// Reset Disasm Structure
Capstone cp;
// Check if the pointer is not null
if(data == NULL)
return 0;
// Round the number of back instructions to 127
if(n < 0)
n = 0;
else if(n > 127)
n = 127;
// Check if the instruction pointer ip is not outside the memory range
if(ip >= size)
ip = size - 1;
// Obvious answer
if(n == 0)
return ip;
if(ip < (uint)n)
return ip;
back = MAX_DISASM_BUFFER * (n + 3); // Instruction length limited to 16
if(ip < back)
back = ip;
addr = ip - back;
pdata = data + addr;
for(i = 0; addr < ip; i++)
{
abuf[i % 128] = addr;
if(!cp.Disassemble(0, pdata, (int)size))
cmdsize = 1;
else
cmdsize = cp.Size();
pdata += cmdsize;
addr += cmdsize;
back -= cmdsize;
size -= cmdsize;
}
if(i < n)
return abuf[0];
else
return abuf[(i - n + 128) % 128];
}
uint disasmnext(unsigned char* data, uint base, uint size, uint ip, int n)
{
int i;
uint cmdsize;
unsigned char* pdata;
// Reset Disasm Structure
Capstone cp;
if(data == NULL)
return 0;
if(ip >= size)
ip = size - 1;
if(n <= 0)
return ip;
pdata = data + ip;
size -= ip;
for(i = 0; i < n && size > 0; i++)
{
if(!cp.Disassemble(0, pdata, (int)size))
cmdsize = 1;
else
cmdsize = cp.Size();
pdata += cmdsize;
ip += cmdsize;
size -= cmdsize;
}
return ip;
}
const char* disasmtext(uint addr)
{
unsigned char buffer[MAX_DISASM_BUFFER] = "";
DbgMemRead(addr, buffer, sizeof(buffer));
Capstone cp;
static char instruction[64] = "";
if(!cp.Disassemble(addr, buffer))
strcpy_s(instruction, "???");
else
sprintf_s(instruction, "%s %s", cp.GetInstr()->mnemonic, cp.GetInstr()->op_str);
return instruction;
}
static void HandleCapstoneOperand(Capstone & cp, int opindex, DISASM_ARG* arg)
{
const cs_x86 & x86 = cp.x86();
const cs_x86_op & op = x86.operands[opindex];
arg->segment = SEG_DEFAULT;
strcpy_s(arg->mnemonic, cp.OperandText(opindex).c_str());
switch(op.type)
{
case X86_OP_REG:
{
const char* regname = cp.RegName((x86_reg)op.reg);
arg->type = arg_normal;
uint value;
if(!valfromstring(regname, &value, true, true))
value = 0;
arg->constant = arg->value = value;
}
break;
case X86_OP_IMM:
{
arg->type = arg_normal;
arg->constant = arg->value = (duint)op.imm;
}
break;
case X86_OP_MEM:
{
arg->type = arg_memory;
const x86_op_mem & mem = op.mem;
if(mem.base == X86_REG_RIP) //rip-relative
arg->constant = cp.Address() + (duint)mem.disp + cp.Size();
else
arg->constant = (duint)mem.disp;
uint value;
if(!valfromstring(arg->mnemonic, &value, true, true))
return;
arg->value = value;
if(DbgMemIsValidReadPtr(value))
{
switch(op.size)
{
case 1:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 1);
break;
case 2:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 2);
break;
case 4:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 4);
break;
case 8:
DbgMemRead(value, (unsigned char*)&arg->memvalue, 8);
break;
}
}
}
break;
}
}
void disasmget(unsigned char* buffer, uint addr, DISASM_INSTR* instr)
{
if(!DbgIsDebugging())
{
if(instr)
instr->argcount = 0;
return;
}
memset(instr, 0, sizeof(DISASM_INSTR));
Capstone cp;
if(!cp.Disassemble(addr, buffer, MAX_DISASM_BUFFER))
{
strcpy_s(instr->instruction, "???");
instr->instr_size = 1;
instr->type = instr_normal;
instr->argcount = 0;
return;
}
sprintf_s(instr->instruction, "%s %s", cp.GetInstr()->mnemonic, cp.GetInstr()->op_str);
const cs_x86 & x86 = cp.GetInstr()->detail->x86;
instr->instr_size = cp.GetInstr()->size;
if(cp.InGroup(CS_GRP_JUMP) || cp.InGroup(CS_GRP_RET) || cp.InGroup(CS_GRP_CALL))
instr->type = instr_branch;
else if(strstr(cp.GetInstr()->op_str, "sp") || strstr(cp.GetInstr()->op_str, "bp"))
instr->type = instr_stack;
else
instr->type = instr_normal;
instr->argcount = cp.x86().op_count <= 3 ? cp.x86().op_count : 3;
for(int i = 0; i < instr->argcount; i++)
HandleCapstoneOperand(cp, i, &instr->arg[i]);
}
void disasmget(uint addr, DISASM_INSTR* instr)
{
if(!DbgIsDebugging())
{
if(instr)
instr->argcount = 0;
return;
}
unsigned char buffer[MAX_DISASM_BUFFER] = "";
DbgMemRead(addr, buffer, sizeof(buffer));
disasmget(buffer, addr, instr);
}
void disasmprint(uint addr)
{
DISASM_INSTR instr;
memset(&instr, 0, sizeof(instr));
disasmget(addr, &instr);
dprintf(">%d:\"%s\":\n", instr.type, instr.instruction);
for(int i = 0; i < instr.argcount; i++)
dprintf(" %d:%d:%"fext"X:%"fext"X:%"fext"X\n", i, instr.arg[i].type, instr.arg[i].constant, instr.arg[i].value, instr.arg[i].memvalue);
}
static bool isasciistring(const unsigned char* data, int maxlen)
{
int len = 0;
for(char* p = (char*)data; *p; len++, p++)
{
if(len >= maxlen)
break;
}
if(len < 2 or len + 1 >= maxlen)
return false;
for(int i = 0; i < len; i++)
if(!isprint(data[i]) and !isspace(data[i]))
return false;
return true;
}
static bool isunicodestring(const unsigned char* data, int maxlen)
{
int len = 0;
for(wchar_t* p = (wchar_t*)data; *p; len++, p++)
{
if(len >= maxlen)
break;
}
if(len < 2 or len + 1 >= maxlen)
return false;
for(int i = 0; i < len * 2; i += 2)
{
if(data[i + 1]) //Extended ASCII only
return false;
if(!isprint(data[i]) and !isspace(data[i]))
return false;
}
return true;
}
bool disasmispossiblestring(uint addr)
{
unsigned char data[11];
memset(data, 0, sizeof(data));
if(!MemRead((void*)addr, data, sizeof(data) - 3, 0))
return false;
uint test = 0;
memcpy(&test, data, sizeof(uint));
if(isasciistring(data, sizeof(data)) or isunicodestring(data, _countof(data)))
return true;
return false;
}
bool disasmgetstringat(uint addr, STRING_TYPE* type, char* ascii, char* unicode, int maxlen)
{
if(type)
*type = str_none;
if(!disasmispossiblestring(addr))
return false;
Memory<unsigned char*> data((maxlen + 1) * 2, "disasmgetstringat:data");
memset(data, 0, (maxlen + 1) * 2);
if(!MemRead((void*)addr, data, (maxlen + 1) * 2, 0))
return false;
uint test = 0;
memcpy(&test, data, sizeof(uint));
if(MemIsValidReadPtr(test))
return false;
if(isasciistring(data, maxlen))
{
if(type)
*type = str_ascii;
int len = (int)strlen((const char*)data);
for(int i = 0, j = 0; i < len; i++)
{
switch(data[i])
{
case '\t':
j += sprintf(ascii + j, "\\t");
break;
case '\f':
j += sprintf(ascii + j, "\\f");
break;
case '\v':
j += sprintf(ascii + j, "\\v");
break;
case '\n':
j += sprintf(ascii + j, "\\n");
break;
case '\r':
j += sprintf(ascii + j, "\\r");
break;
case '\\':
j += sprintf(ascii + j, "\\\\");
break;
case '\"':
j += sprintf(ascii + j, "\\\"");
break;
default:
j += sprintf(ascii + j, "%c", data[i]);
break;
}
}
return true;
}
else if(isunicodestring(data, maxlen))
{
if(type)
*type = str_unicode;
int len = (int)wcslen((const wchar_t*)data);
for(int i = 0, j = 0; i < len * 2; i += 2)
{
switch(data[i])
{
case '\t':
j += sprintf(unicode + j, "\\t");
break;
case '\f':
j += sprintf(unicode + j, "\\f");
break;
case '\v':
j += sprintf(unicode + j, "\\v");
break;
case '\n':
j += sprintf(unicode + j, "\\n");
break;
case '\r':
j += sprintf(unicode + j, "\\r");
break;
case '\\':
j += sprintf(unicode + j, "\\\\");
break;
case '\"':
j += sprintf(unicode + j, "\\\"");
break;
default:
j += sprintf(unicode + j, "%c", data[i]);
break;
}
}
return true;
}
return false;
}
int disasmgetsize(uint addr, unsigned char* data)
{
Capstone cp;
if(!cp.Disassemble(addr, data, MAX_DISASM_BUFFER))
return 1;
return cp.Size();
}
int disasmgetsize(uint addr)
{
char data[MAX_DISASM_BUFFER];
if(!MemRead((void*)addr, data, sizeof(data), 0))
return 1;
return disasmgetsize(addr, (unsigned char*)data);
}