def is_valid_signature(provider: BaseProvider, data: str, signature: str,
signer_address: str) -> bool:
"""Check the validity of the supplied signature.
Check if the supplied `signature`:code: corresponds to signing `data`:code:
with the private key corresponding to `signer_address`:code:.
: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.
:returns: Tuple consisting of a boolean and a string. Boolean is true if
valid, false otherwise. If false, the string describes the reason.
>>> is_valid_signature(
... Web3.HTTPProvider("http://127.0.0.1:8545"),
... '0x6927e990021d23b1eb7b8789f6a6feaf98fe104bb0cf8259421b79f9a34222b0',
... '0x1B61a3ed31b43c8780e905a260a35faefcc527be7516aa11c0256729b5b351bc3340349190569279751135161d22529dc25add4f6069af05be04cacbda2ace225403',
... '0x5409ed021d9299bf6814279a6a1411a7e866a631',
... )
True
""" # noqa: E501 (line too long)
assert_is_provider(provider, "provider")
assert_is_hex_string(data, "data")
assert_is_hex_string(signature, "signature")
assert_is_address(signer_address, "signer_address")
return Exchange(
provider,
chain_to_addresses(ChainId(1 # hard-coded to always be mainnet
)).exchange,
).is_valid_hash_signature.call(
bytes.fromhex(remove_0x_prefix(HexStr(data))),
to_checksum_address(signer_address),
bytes.fromhex(remove_0x_prefix(HexStr(signature))),
)
def is_valid_signature(
provider: BaseProvider, data: str, signature: str, signer_address: str
) -> Tuple[bool, str]:
"""Check the validity of the supplied signature.
Check if the supplied `signature`:code: corresponds to signing `data`:code:
with the private key corresponding to `signer_address`:code:.
: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.
:returns: Tuple consisting of a boolean and a string. Boolean is true if
valid, false otherwise. If false, the string describes the reason.
>>> is_valid_signature(
... Web3.HTTPProvider("http://127.0.0.1:8545"),
... '0x6927e990021d23b1eb7b8789f6a6feaf98fe104bb0cf8259421b79f9a34222b0',
... '0x1B61a3ed31b43c8780e905a260a35faefcc527be7516aa11c0256729b5b351bc3340349190569279751135161d22529dc25add4f6069af05be04cacbda2ace225403',
... '0x5409ed021d9299bf6814279a6a1411a7e866a631',
... )
(True, '')
""" # noqa: E501 (line too long)
assert_is_provider(provider, "provider")
assert_is_hex_string(data, "data")
assert_is_hex_string(signature, "signature")
assert_is_address(signer_address, "signer_address")
web3_instance = Web3(provider)
# false positive from pylint: disable=no-member
contract_address = NETWORK_TO_ADDRESSES[
NetworkId(int(web3_instance.net.version))
].exchange
# false positive from pylint: disable=no-member
contract: Contract = web3_instance.eth.contract(
address=to_checksum_address(contract_address),
abi=zero_ex.contract_artifacts.abi_by_name("Exchange"),
)
try:
return (
contract.functions.isValidSignature(
data, to_checksum_address(signer_address), signature
).call(),
"",
)
except web3.exceptions.BadFunctionCallOutput as exception:
known_revert_reasons = [
"LENGTH_GREATER_THAN_0_REQUIRED",
"SIGNATURE_ILLEGAL",
"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}")
def sign_hash(
provider: BaseProvider, signer_address: str, hash_hex: str
) -> str:
"""Sign a message with the given hash, and return the signature.
:param provider: A Web3 provider.
:param signer_address: The address of the signing account.
:param hash_hex: A hex string representing the hash, like that returned
from `generate_order_hash_hex()`:code:.
:returns: A string, of ASCII hex digits, representing the signature.
>>> provider = Web3.HTTPProvider("http://127.0.0.1:8545")
>>> sign_hash(
... provider,
... Web3(provider).geth.personal.listAccounts()[0],
... '0x34decbedc118904df65f379a175bb39ca18209d6ce41d5ed549d54e6e0a95004',
... )
'0x1b117902c86dfb95fe0d1badd983ee166ad259b27acb220174cbb4460d872871137feabdfe76e05924b484789f79af4ee7fa29ec006cedce1bbf369320d034e10b03'
""" # noqa: E501 (line too long)
assert_is_provider(provider, "provider")
assert_is_address(signer_address, "signer_address")
assert_is_hex_string(hash_hex, "hash_hex")
web3_instance = Web3(provider)
# false positive from pylint: disable=no-member
signature = web3_instance.eth.sign( # type: ignore
signer_address, hexstr=hash_hex.replace("0x", "")
).hex()
valid_v_param_values = [27, 28]
# HACK: There is no consensus on whether the signatureHex string should be
# formatted as v + r + s OR r + s + v, and different clients (even
# different versions of the same client) return the signature params in
# different orders. In order to support all client implementations, we
# parse the signature in both ways, and evaluate if either one is a valid
# signature. r + s + v is the most prevalent format from eth_sign, so we
# attempt this first.
ec_signature = _parse_signature_hex_as_rsv(signature)
if ec_signature["v"] in valid_v_param_values:
signature_as_vrst_hex = (
_convert_ec_signature_to_vrs_hex(ec_signature)
+ _Constants.SignatureType.ETH_SIGN.value.to_bytes(
1, byteorder="big"
).hex()
)
(valid, _) = is_valid_signature(
provider, hash_hex, signature_as_vrst_hex, signer_address
)
if valid is True:
return signature_as_vrst_hex
ec_signature = _parse_signature_hex_as_vrs(signature)
if ec_signature["v"] in valid_v_param_values:
signature_as_vrst_hex = (
_convert_ec_signature_to_vrs_hex(ec_signature)
+ _Constants.SignatureType.ETH_SIGN.value.to_bytes(
1, byteorder="big"
).hex()
)
(valid, _) = is_valid_signature(
provider, hash_hex, signature_as_vrst_hex, signer_address
)
if valid is True:
return signature_as_vrst_hex
raise RuntimeError(
"Signature returned from web3 provider is in an unknown format."
+ " Attempted to parse as RSV and as VRS."
)
