Zydis  v2.0.0-alpha1
Zyan Disassembler Engine (Zydis)

License: MIT Gitter

Fast and lightweight x86/x86-64 disassembler library.

Features

  • Supports all x86 and x86-64 (AMD64) general-purpose and system instructions.
  • Supports pretty much all ISA extensions:
    • FPU (x87), MMX
    • SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, SSE4A, AESNI
    • AVX, AVX2, AVX512BW, AVX512CD, AVX512DQ, AVX512ER, AVX512F, AVX512PF, AVX512VL
    • ADX, BMI1, BMI2, FMA, FMA4
    • ..
  • Optimized for high performance
  • No dynamic memory allocation
    • Perfect for kernel-mode drivers and embedded devices
  • Very small file-size overhead compared to other common disassembler libraries
  • Complete doxygen documentation

Roadmap

  • Language bindings [v2.0 final]
  • Tests [v2.0 final]
  • Graphical editor for the instruction-database [v2.0 final]
  • Implement CMake feature gates. Currently, everything is always included. [v2.0 final]
  • Encoding support [v2.1]

Quick Example

The following example program uses Zydis to disassemble a given memory buffer and prints the output to the console.

#include <stdio.h>
#include <Zydis/Zydis.h>
int main()
{
uint8_t data[] =
{
0x51, 0x8D, 0x45, 0xFF, 0x50, 0xFF, 0x75, 0x0C, 0xFF, 0x75,
0x08, 0xFF, 0x15, 0xA0, 0xA5, 0x48, 0x76, 0x85, 0xC0, 0x0F,
0x88, 0xFC, 0xDA, 0x02, 0x00
};
ZydisDecoder decoder;
ZydisDecoderInit(&decoder, ZYDIS_MACHINE_MODE_LONG_64, ZYDIS_ADDRESS_WIDTH_64);
ZydisFormatter formatter;
ZydisFormatterInitEx(&formatter, ZYDIS_FORMATTER_STYLE_INTEL,
ZYDIS_FMTFLAG_FORCE_SEGMENTS | ZYDIS_FMTFLAG_FORCE_OPERANDSIZE,
ZYDIS_FORMATTER_ADDR_ABSOLUTE, ZYDIS_FORMATTER_DISP_DEFAULT, ZYDIS_FORMATTER_IMM_DEFAULT);
uint64_t instructionPointer = 0x007FFFFFFF400000;
ZydisDecodedInstruction instruction;
char buffer[256];
while (ZYDIS_SUCCESS(
ZydisDecoderDecodeBuffer(decoder, data, length, instructionPointer, &instruction)))
{
data += instruction.length;
length -= instruction.length;
instructionPointer += instruction.length;
printf("%016" PRIX64 " ", instruction.instrAddress);
ZydisFormatterFormatInstruction(&formatter, &instruction, &buffer[0], sizeof(buffer));
printf(" %s\n", &buffer[0]);
}
}
ZydisDecoderDecodeBuffer
ZYDIS_EXPORT ZydisStatus ZydisDecoderDecodeBuffer(const ZydisDecoder *decoder, const void *buffer, size_t bufferLen, uint64_t instructionPointer, ZydisDecodedInstruction *instruction)
Decodes the instruction in the given input buffer.
ZydisDecoderInit
ZYDIS_EXPORT ZydisStatus ZydisDecoderInit(ZydisDecoder *decoder, ZydisMachineMode machineMode, ZydisAddressWidth addressWidth)
Initializes the given ZydisDecoder instance.
ZYDIS_FORMATTER_ADDR_ABSOLUTE
@ ZYDIS_FORMATTER_ADDR_ABSOLUTE
Displays absolute addresses instead of relative ones.
Definition: Formatter.h:98
ZYDIS_FORMATTER_IMM_DEFAULT
@ ZYDIS_FORMATTER_IMM_DEFAULT
Currently defaults to ZYDIS_FORMATTER_IMM_HEX_UNSIGNED.
Definition: Formatter.h:166
ZYDIS_FORMATTER_DISP_DEFAULT
@ ZYDIS_FORMATTER_DISP_DEFAULT
Currently defaults to ZYDIS_FORMATTER_DISP_HEX_SIGNED.
Definition: Formatter.h:132
ZYDIS_FMTFLAG_FORCE_SEGMENTS
#define ZYDIS_FMTFLAG_FORCE_SEGMENTS
Forces the formatter to always print the segment register of memory-operands, instead of ommiting imp...
Definition: Formatter.h:73
ZydisFormatterInitEx
ZYDIS_EXPORT ZydisStatus ZydisFormatterInitEx(ZydisFormatter *formatter, ZydisFormatterStyle style, ZydisFormatterFlags flags, ZydisFormatterAddressFormat addressFormat, ZydisFormatterDisplacementFormat displacementFormat, ZydisFormatterImmediateFormat immmediateFormat)
Initializes the given ZydisFormatter instance.
ZYDIS_FORMATTER_STYLE_INTEL
@ ZYDIS_FORMATTER_STYLE_INTEL
Generates intel-style disassembly.
Definition: Formatter.h:55
ZYDIS_FMTFLAG_FORCE_OPERANDSIZE
#define ZYDIS_FMTFLAG_FORCE_OPERANDSIZE
Forces the formatter to always print the size of memory-operands.
Definition: Formatter.h:77
ZydisFormatterFormatInstruction
ZYDIS_EXPORT ZydisStatus ZydisFormatterFormatInstruction(const ZydisFormatter *formatter, ZydisDecodedInstruction *instruction, char *buffer, size_t bufferLen)
Formats the given instruction and writes it into the output buffer.
ZYDIS_ADDRESS_WIDTH_64
@ ZYDIS_ADDRESS_WIDTH_64
Definition: SharedTypes.h:116
ZYDIS_MACHINE_MODE_LONG_64
@ ZYDIS_MACHINE_MODE_LONG_64
64 bit mode.
Definition: SharedTypes.h:76
ZYDIS_SUCCESS
#define ZYDIS_SUCCESS(status)
Checks if a zydis operation was successfull.
Definition: Status.h:149
ZydisDecodedInstruction_
Defines the ZydisDecodedInstruction struct.
Definition: DecoderTypes.h:676
ZydisDecodedInstruction_::instrAddress
uint64_t instrAddress
The instruction address points at the current instruction (relative to the initial instruction pointe...
Definition: DecoderTypes.h:733
ZydisDecodedInstruction_::length
uint8_t length
The length of the decoded instruction.
Definition: DecoderTypes.h:688
ZydisDecoder_
Defines the ZydisDecoder struct.
Definition: Decoder.h:78
ZydisFormatter_
Defines the ZydisFormatter struct.
Definition: Formatter.h:425

Sample Output

The above example program generates the following output:

007FFFFFFF400000 push rcx
007FFFFFFF400001 lea eax, dword ptr ss:[rbp-0x01]
007FFFFFFF400004 push rax
007FFFFFFF400005 push qword ptr ss:[rbp+0x0C]
007FFFFFFF400008 push qword ptr ss:[rbp+0x08]
007FFFFFFF40000B call qword ptr ds:[0x008000007588A5B1]
007FFFFFFF400011 test eax, eax
007FFFFFFF400013 js 0x007FFFFFFF42DB15

Compilation

Zydis builds cleanly on most platforms without any external dependencies. You can use CMake to generate project files for your favorite C99 compiler.

# Linux and OS X
git clone 'https://github.com/zyantific/zydis.git'
cd zydis
mkdir build && cd build
cmake ..
make

ZydisInfo tool

ZydisInfo

License

Zydis is licensed under the MIT license.