Octopus

Muitos agradecimentos à QuoScient por ter patrocinado este projeto.

Octopus é um framework de análise de segurança para módulos WebAssembly e Smart Contracts de Blockchain.

O objetivo do Octopus é fornecer uma maneira fácil de analisar módulos WebAssembly de código fechado e bytecode de smart contracts para compreender mais profundamente seus comportamentos internos.

Features

• Explorer: Implementação de cliente JSON-RPC do Octopus para comunicar com plataformas blockchain
• Disassembler: Octopus pode traduzir bytecode em representação assembly
• Control Flow Analysis: Octopus pode gerar um Grafo de Fluxo de Controle (CFG)
• Call Flow Analysis: Octopus pode gerar um Grafo de Fluxo de Chamadas (nível de função)
• IR conversion (SSA): Octopus pode simplificar assembly em representação Static Single Assignment (SSA)
• Symbolic Execution: Octopus usa execução simbólica para encontrar novos caminhos em um programa

Plataformas / Arquiteturas

Octopus suporta os seguintes tipos de programas/smart contracts:

• Módulo WebAssembly (WASM)
• Bitcoin script (BTC script)
• Contratos inteligentes Ethereum (bytecode EVM & Ewasm)
• Contratos inteligentes EOS (WASM)
• Contratos inteligentes NEO (bytecode AVM)

	BTC	ETH (EVM)	ETH (WASM)	EOS	NEO		WASM
Explorer	✔️	✔️	✔️	✔️	✔️		⭕
Disassembler	✔️	✔️	✔️	✔️	✔️		✔️
Control Flow Analysis	✖️	✔️	✔️	✔️	✔️		✔️
Call Flow Analysis	✖️	➕	✔️	✔️	➕		✔️
IR conversion (SSA)	✖️	✔️	➕	➕	✖️		✔️
Symbolic Execution	✖️	➕	➕	➕	✖️		➕

• PyPI package ✔️
• Docker ✔️

✔️ DONE / ➕ WIP / ✖️ TODO / ⭕ N/A

Requisitos

Octopus é suportado em Linux (idealmente Ubuntu 16.04) e requer Python >=3.5 (idealmente 3.6).

Dependências:

• Geração de grafos: graphviz
• Explorer: requests
• Execução Simbólica: z3-solver
• Wasm: wasm

Quick Start

• Instalar dependências do sistema```

Install system dependencies

sudo apt-get update && sudo apt-get install python-pip graphviz xdg-utils -y

- Instalar o Octopus:```
# Download Octopus
git clone https://github.com/pventuzelo/octopus
cd octopus

# Install Octopus library/CLI and its dependencies
python3 setup.py install

ou```

but prefer the first way to install if possible

pip3 install octopus

- Executar testes```
# Run tests for all platforms (disassembly, CFG, ...)
./run_tests.sh
# Run tests that require internet access (explorer tests)
./run_explorer_tests.sh

# Run tests for only one platforms
# {btc, eth, eos, neo, wasm}_run_tests.sh
cd octopus/tests/
./wasm_run_tests.sh

Contêiner Docker

Um contêiner Docker que fornece o conjunto de ferramentas está disponível em docker hub. Em um terminal, execute os seguintes comandos:``` docker pull smartbugs/octopus docker run -it smartbugs/octopus cd octopus python3 octopus_eth_evm.py -s -f examples/ETH/evm_bytecode/61EDCDf5bb737ADffE5043706e7C5bb1f1a56eEA.bytecode

## Ferramentas de linha de comando

* WebAssembly: [octopus_wasm.py](https://github.com/fuzzinglabs/octopus/blob/master/octopus_wasm.py)
* Ethereum (EVM): [octopus_eth_evm.py](https://github.com/fuzzinglabs/octopus/blob/master/octopus_eth_evm.py)


## Exemplos detalhados usando APIs

<details><summary>WebAssembly</summary>
<p>

#### Desmontador

Desmontagem de um módulo Wasm:```python
from octopus.arch.wasm.disassembler import WasmDisassembler

FILE = "examples/wasm/samples/helloworld.wasm"

with open(FILE, 'rb') as f:
    module_bytecode = f.read()

disasm = WasmDisassembler()
# return list of functions instructions (list)
print(disasm.disassemble_module(module_bytecode))
#[[<octopus.arch.wasm.instruction.WasmInstruction at 0x7f85e4904278>,<octopus.arch.wasm.instruction.WasmInstruction at 0x7f85e4904f60>,<octopus.arch.wasm.instruction.WasmInstruction at 0x7f85e4904ef0>]]

print()
# return text of functions code
print(disasm.disassemble_module(module_bytecode, r_format='text'))
# func 0
# i32.const 0
# call 0
# end

Desmontagem do bytecode wasm:```python from octopus.arch.wasm.disassembler import WasmDisassembler

bytecode in WebAssembly is the function code (i.e. function body)

bytecode = b'\x02\x7fA\x18\x10\x1cA\x00\x0f\x0b'

create a WasmDisassembler object

disasm = WasmDisassembler(bytecode)

disassemble bytecode into a list of WasmInstruction

attributes r_format='list' by default

print(disasm.disassemble())

#[<octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904eb8>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904278>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904390>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904ef0>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904f60>, <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4901048>] print() print(disasm.disassemble(r_format='reverse'))

#{0: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4901048>, 1: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904240>, 2: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904f60>, 3: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904ef0>, 4: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904278>, 5: <octopus.arch.wasm.instruction.WasmInstruction object at 0x7f85e4904390>} print() print(disasm.disassemble(r_format='text'))

block -1

i32.const 24

call 28

i32.const 0

return

end

#### ModuleAnalyzer```python
from octopus.arch.wasm.analyzer import WasmModuleAnalyzer

FILE = "examples/wasm/samples/hello_wasm_studio.wasm"

with open(FILE, 'rb') as f:
    module_bytecode = f.read()

# return list of functions instructions (list)
# attributes analysis=True by default
analyzer = WasmModuleAnalyzer(module_bytecode)