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"""Signature utilities."""
from typing import Dict, Tuple
import json
from pkg_resources import resource_string
from eth_utils import is_address, to_checksum_address
from web3 import Web3
import web3.exceptions
from web3.utils import datatypes
from zero_ex.dev_utils.type_assertions import assert_is_hex_string
# prefer `black` formatting. pylint: disable=C0330
EXCHANGE_ABI = json.loads(
resource_string("zero_ex.contract_artifacts", "artifacts/Exchange.json")
)["compilerOutput"]["abi"]
network_to_exchange_addr: Dict[str, str] = {
"1": "0x4f833a24e1f95d70f028921e27040ca56e09ab0b",
"3": "0x4530c0483a1633c7a1c97d2c53721caff2caaaaf",
"42": "0x35dd2932454449b14cee11a94d3674a936d5d7b2",
"50": "0x48bacb9266a570d521063ef5dd96e61686dbe788",
}
# prefer `black` formatting. pylint: disable=C0330
def is_valid_signature(
provider: Web3.HTTPProvider, data: str, signature: str, signer_address: str
) -> Tuple[bool, str]:
# docstring considered all one line by pylint: disable=line-too-long
"""Check the validity of the supplied signature.
Check if the supplied ``signature`` corresponds to signing ``data`` with
the private key corresponding to ``signer_address``.
:param provider: A Web3 provider able to access the 0x Exchange contract.
:param data: The hex encoded data signed by the supplied signature.
:param signature: The hex encoded signature.
:param signer_address: The hex encoded address that signed the data to
produce the supplied signature.
:rtype: Boolean indicating whether the given signature is valid.
>>> is_valid_signature(
... Web3.HTTPProvider("http://127.0.0.1:8545"),
... '0x6927e990021d23b1eb7b8789f6a6feaf98fe104bb0cf8259421b79f9a34222b0',
... '0x1B61a3ed31b43c8780e905a260a35faefcc527be7516aa11c0256729b5b351bc3340349190569279751135161d22529dc25add4f6069af05be04cacbda2ace225403',
... '0x5409ed021d9299bf6814279a6a1411a7e866a631',
... )
(True, '')
""" # noqa: E501 (line too long)
# TODO: make this provider check more flexible. pylint: disable=fixme
# https://app.asana.com/0/684263176955174/901300863045491/f
if not isinstance(provider, Web3.HTTPProvider):
raise TypeError("provider is not a Web3.HTTPProvider")
assert_is_hex_string(data, "data")
assert_is_hex_string(signature, "signature")
assert_is_hex_string(signer_address, "signer_address")
if not is_address(signer_address):
raise ValueError("signer_address is not a valid address")
web3_instance = Web3(provider)
# false positive from pylint: disable=no-member
network_id = web3_instance.net.version
contract_address = network_to_exchange_addr[network_id]
# false positive from pylint: disable=no-member
contract: datatypes.Contract = web3_instance.eth.contract(
address=to_checksum_address(contract_address), abi=EXCHANGE_ABI
)
try:
return (
contract.call().isValidSignature(
data, to_checksum_address(signer_address), signature
),
"",
)
except web3.exceptions.BadFunctionCallOutput as exception:
known_revert_reasons = [
"LENGTH_GREATER_THAN_0_REQUIRED",
"SIGNATURE_UNSUPPORTED",
"LENGTH_0_REQUIRED",
"LENGTH_65_REQUIRED",
]
for known_revert_reason in known_revert_reasons:
if known_revert_reason in str(exception):
return (False, known_revert_reason)
return (False, f"Unknown: {exception}")
|
