/**
* @brief Return the address of the nth instruction after the instruction pointed by ip. @n
* This function has been grabbed from OllyDbg ("Disassembleforward" in asmserv.c)
*
* @param[in] data Address of the data to disassemble
* @param[in] base Original base address of the memory page (Required to disassemble destination addresses)
* @param[in] size Size of the data block pointed by data
* @param[in] ip RVA of the current instruction (Relative to data pointer)
* @param[in] n Number of instruction next
*
* @return Return the RVA (Relative to the data pointer) of the nth instruction after the instruction pointed by ip
*/
ulong QBeaEngine::DisassembleNext(byte_t* data, duint base, duint size, duint 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(mCodeFoldingManager && mCodeFoldingManager->isFolded(ip + base))
{
cmdsize = mCodeFoldingManager->getFoldEnd(ip + base) - (ip + base) + 1;
}
else
{
if(!cp.DisassembleSafe(ip + base, pdata, (int)size))
cmdsize = 1;
else
cmdsize = cp.Size();
cmdsize = mEncodeMap->getDataSize(base + ip, cmdsize);
}
pdata += cmdsize;
ip += cmdsize;
size -= cmdsize;
}
return ip;
}
/**
* @brief Return the address of the nth instruction before the instruction pointed by ip. @n
* This function has been grabbed from OllyDbg ("Disassembleback" in asmserv.c)
*
* @param[in] data Address of the data to disassemble
* @param[in] base Original base address of the memory page (Required to disassemble destination addresses)
* @param[in] size Size of the data block pointed by data
* @param[in] ip RVA of the current instruction (Relative to data pointer)
* @param[in] n Number of instruction back
*
* @return Return the RVA (Relative to the data pointer) of the nth instruction before the instruction pointed by ip
*/
ulong QBeaEngine::DisassembleBack(byte_t* data, duint base, duint size, duint ip, int n)
{
int i;
uint abuf[128], 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;
//TODO: buffer overflow due to unchecked "back" value
back = MAX_DISASM_BUFFER * (n + 3); // Instruction length limited to 16
if(ip < back)
back = ip;
addr = ip - back;
if(mCodeFoldingManager && mCodeFoldingManager->isFolded(addr + base))
{
duint newback = mCodeFoldingManager->getFoldBegin(addr + base);
if(newback >= base && newback < size + base)
addr = newback - base;
}
pdata = data + addr;
for(i = 0; addr < ip; i++)
{
abuf[i % 128] = addr;
if(mCodeFoldingManager && mCodeFoldingManager->isFolded(addr + base))
{
duint newaddr = mCodeFoldingManager->getFoldBegin(addr + base);
if(newaddr >= base)
{
addr = newaddr - base;
}
cmdsize = mCodeFoldingManager->getFoldEnd(addr + base) - (addr + base) + 1;
}
else
{
if(!cp.DisassembleSafe(addr + base, pdata, (int)size))
cmdsize = 2; //heuristic for better output (FF FE or FE FF are usually part of an instruction)
else
cmdsize = cp.Size();
cmdsize = mEncodeMap->getDataSize(base + addr, cmdsize);
}
pdata += cmdsize;
addr += cmdsize;
back -= cmdsize;
size -= cmdsize;
}
if(i < n)
return abuf[0];
else
return abuf[(i - n + 128) % 128];
}
