def _data_to_sign(self) -> bytes:
""" Return the binary data to be/which was signed """
assert self.non_closing_signature
packed = pack_reward_proof(
chain_id=self.balance_proof.chain_id,
token_network_address=self.balance_proof.token_network_address,
reward_amount=self.reward_amount,
monitoring_service_contract_address=self.monitoring_service_contract_address,
non_closing_participant=self.non_closing_participant,
non_closing_signature=self.non_closing_signature,
)
return packed
def verify_request_monitoring(self, partner_address: Address,
requesting_address: Address) -> bool:
""" One should only use this method to verify integrity and signatures of a
RequestMonitoring message. """
if not self.non_closing_signature:
return False
balance_proof_data = pack_balance_proof(
nonce=self.balance_proof.nonce,
balance_hash=self.balance_proof.balance_hash,
additional_hash=self.balance_proof.additional_hash,
canonical_identifier=CanonicalIdentifier(
chain_identifier=self.balance_proof.chain_id,
token_network_address=self.balance_proof.token_network_address,
channel_identifier=self.balance_proof.channel_identifier,
),
)
blinded_data = pack_signed_balance_proof(
msg_type=MessageTypeId.BALANCE_PROOF_UPDATE,
nonce=self.balance_proof.nonce,
balance_hash=self.balance_proof.balance_hash,
additional_hash=self.balance_proof.additional_hash,
canonical_identifier=CanonicalIdentifier(
chain_identifier=self.balance_proof.chain_id,
token_network_address=self.balance_proof.token_network_address,
channel_identifier=self.balance_proof.channel_identifier,
),
partner_signature=self.balance_proof.signature,
)
reward_proof_data = pack_reward_proof(
chain_id=self.balance_proof.chain_id,
token_network_address=self.balance_proof.token_network_address,
reward_amount=self.reward_amount,
monitoring_service_contract_address=self.
monitoring_service_contract_address,
non_closing_participant=requesting_address,
non_closing_signature=self.non_closing_signature,
)
reward_proof_signature = self.reward_proof_signature or EMPTY_SIGNATURE
return (recover(balance_proof_data,
self.balance_proof.signature) == partner_address
and recover(blinded_data,
self.non_closing_signature) == requesting_address
and recover(reward_proof_data,
reward_proof_signature) == requesting_address)
def test_request_monitoring() -> None:
properties = factories.BalanceProofSignedStateProperties(
pkey=PARTNER_PRIVKEY)
balance_proof = factories.create(properties)
partner_signed_balance_proof = SignedBlindedBalanceProof.from_balance_proof_signed_state(
balance_proof)
request_monitoring = RequestMonitoring(
balance_proof=partner_signed_balance_proof,
non_closing_participant=ADDRESS,
reward_amount=TokenAmount(55),
signature=EMPTY_SIGNATURE,
monitoring_service_contract_address=MSC_ADDRESS,
)
assert request_monitoring
request_monitoring.sign(signer)
as_dict = DictSerializer.serialize(request_monitoring)
assert DictSerializer.deserialize(as_dict) == request_monitoring
# RequestMonitoring can be created directly from BalanceProofSignedState
direct_created = RequestMonitoring.from_balance_proof_signed_state(
balance_proof=balance_proof,
non_closing_participant=ADDRESS,
reward_amount=TokenAmount(55),
monitoring_service_contract_address=MSC_ADDRESS,
)
# `direct_created` is not signed while request_monitoring is
assert DictSerializer().serialize(
direct_created) != DictSerializer().serialize(request_monitoring)
direct_created.sign(signer)
# Instances created from same balance proof are equal
assert direct_created == request_monitoring
other_balance_proof = factories.create(
factories.replace(properties, message_hash=keccak(b"2")))
other_instance = RequestMonitoring.from_balance_proof_signed_state(
balance_proof=other_balance_proof,
non_closing_participant=ADDRESS,
reward_amount=TokenAmount(55),
monitoring_service_contract_address=MSC_ADDRESS,
)
other_instance.sign(signer)
# different balance proof ==> non-equality
assert other_instance != request_monitoring
# test signature verification
assert request_monitoring.non_closing_signature
reward_proof_data = pack_reward_proof(
token_network_address=request_monitoring.balance_proof.
token_network_address,
chain_id=request_monitoring.balance_proof.chain_id,
reward_amount=request_monitoring.reward_amount,
monitoring_service_contract_address=MSC_ADDRESS,
non_closing_participant=ADDRESS,
non_closing_signature=request_monitoring.non_closing_signature,
)
assert request_monitoring.reward_proof_signature
assert recover(reward_proof_data,
request_monitoring.reward_proof_signature) == ADDRESS
blinded_data = pack_signed_balance_proof(
msg_type=MessageTypeId.BALANCE_PROOF_UPDATE,
nonce=request_monitoring.balance_proof.nonce,
balance_hash=request_monitoring.balance_proof.balance_hash,
additional_hash=request_monitoring.balance_proof.additional_hash,
canonical_identifier=factories.make_canonical_identifier(
chain_identifier=request_monitoring.balance_proof.chain_id,
token_network_address=request_monitoring.balance_proof.
token_network_address,
channel_identifier=request_monitoring.balance_proof.
channel_identifier,
),
partner_signature=request_monitoring.balance_proof.signature,
)
assert recover(blinded_data,
request_monitoring.non_closing_signature) == ADDRESS
balance_proof_data = pack_balance_proof(
nonce=request_monitoring.balance_proof.nonce,
balance_hash=request_monitoring.balance_proof.balance_hash,
additional_hash=request_monitoring.balance_proof.additional_hash,
canonical_identifier=factories.make_canonical_identifier(
chain_identifier=request_monitoring.balance_proof.chain_id,
token_network_address=request_monitoring.balance_proof.
token_network_address,
channel_identifier=request_monitoring.balance_proof.
channel_identifier,
),
)
assert (recover(
balance_proof_data,
request_monitoring.balance_proof.signature) == PARTNER_ADDRESS)
assert request_monitoring.verify_request_monitoring(
PARTNER_ADDRESS, ADDRESS)
def test_tamper_request_monitoring():
""" This test shows ways, how the current implementation of the RequestMonitoring's
signature scheme might be used by an attacker to tamper with the BalanceProof that is
incorporated in the RequestMonitoring message, if not all three signatures are verified."""
msc_address = bytes([1] * 20)
properties = factories.BalanceProofSignedStateProperties(
pkey=PARTNER_PRIVKEY)
balance_proof = factories.create(properties)
partner_signed_balance_proof = SignedBlindedBalanceProof.from_balance_proof_signed_state(
balance_proof)
request_monitoring = RequestMonitoring(
balance_proof=partner_signed_balance_proof,
reward_amount=55,
signature=EMPTY_SIGNATURE,
monitoring_service_contract_address=msc_address,
non_closing_participant=ADDRESS,
)
request_monitoring.sign(signer)
# This is the signature, that is supposed to authenticate the message that a monitoring
# service receives from a node. Note: It is generated on a valid Balance proof here and reused
# to authenticate invalid messages throughout the rest of the test.
exploited_signature = request_monitoring.reward_proof_signature
reward_proof_data = pack_reward_proof(
chain_id=request_monitoring.balance_proof.chain_id,
token_network_address=request_monitoring.balance_proof.
token_network_address,
reward_amount=request_monitoring.reward_amount,
monitoring_service_contract_address=msc_address,
non_closing_participant=ADDRESS,
non_closing_signature=request_monitoring.non_closing_signature,
)
# An attacker might change the balance hash
partner_signed_balance_proof.balance_hash = "tampered".encode()
tampered_balance_hash_request_monitoring = RequestMonitoring(
balance_proof=partner_signed_balance_proof,
reward_amount=55,
non_closing_participant=ADDRESS,
signature=EMPTY_SIGNATURE,
monitoring_service_contract_address=MSC_ADDRESS,
)
tampered_bp = tampered_balance_hash_request_monitoring.balance_proof
tampered_balance_hash_reward_proof_data = pack_reward_proof(
chain_id=tampered_bp.chain_id,
token_network_address=request_monitoring.balance_proof.
token_network_address,
reward_amount=tampered_balance_hash_request_monitoring.reward_amount,
monitoring_service_contract_address=msc_address,
non_closing_participant=ADDRESS,
non_closing_signature=request_monitoring.non_closing_signature,
)
# The signature works/is unaffected by that change...
recovered_address_tampered = recover(
tampered_balance_hash_reward_proof_data, exploited_signature)
assert recover(reward_proof_data,
exploited_signature) == recovered_address_tampered
assert recover(tampered_balance_hash_reward_proof_data,
exploited_signature) == ADDRESS
# ...but overall verification fails
assert not tampered_balance_hash_request_monitoring.verify_request_monitoring(
PARTNER_ADDRESS, ADDRESS)
# An attacker might change the additional_hash
partner_signed_balance_proof.additional_hash = "tampered".encode()
tampered_additional_hash_request_monitoring = RequestMonitoring(
balance_proof=partner_signed_balance_proof,
reward_amount=55,
signature=EMPTY_SIGNATURE,
monitoring_service_contract_address=MSC_ADDRESS,
non_closing_participant=ADDRESS,
)
tampered_bp = tampered_additional_hash_request_monitoring.balance_proof
tampered_additional_hash_reward_proof_data = pack_reward_proof(
chain_id=tampered_bp.chain_id,
token_network_address=(tampered_additional_hash_request_monitoring.
balance_proof.token_network_address),
reward_amount=tampered_additional_hash_request_monitoring.
reward_amount,
monitoring_service_contract_address=msc_address,
non_closing_participant=ADDRESS,
non_closing_signature=request_monitoring.non_closing_signature,
)
# The signature works/is unaffected by that change...
recovered_address_tampered = recover(
tampered_additional_hash_reward_proof_data, exploited_signature)
assert recover(reward_proof_data,
exploited_signature) == recovered_address_tampered
assert recovered_address_tampered == ADDRESS
# ...but overall verification fails
assert not tampered_balance_hash_request_monitoring.verify_request_monitoring(
PARTNER_ADDRESS, ADDRESS)
# An attacker can change the non_closing_signature
partner_signed_balance_proof.non_closing_signature = "tampered".encode()
tampered_non_closing_signature_request_monitoring = RequestMonitoring(
balance_proof=partner_signed_balance_proof,
reward_amount=55,
signature=EMPTY_SIGNATURE,
monitoring_service_contract_address=MSC_ADDRESS,
non_closing_participant=ADDRESS,
)
tampered_bp = tampered_non_closing_signature_request_monitoring.balance_proof
tampered_non_closing_signature_reward_proof_data = pack_reward_proof(
chain_id=tampered_bp.chain_id,
token_network_address=(
tampered_non_closing_signature_request_monitoring.balance_proof.
token_network_address),
reward_amount=tampered_non_closing_signature_request_monitoring.
reward_amount,
monitoring_service_contract_address=msc_address,
non_closing_participant=ADDRESS,
non_closing_signature=request_monitoring.non_closing_signature,
)
# The signature works/is unaffected by that change...
recovered_address_tampered = recover(
tampered_non_closing_signature_reward_proof_data, exploited_signature)
assert recover(reward_proof_data,
exploited_signature) == recovered_address_tampered
assert recovered_address_tampered == ADDRESS
# ...but overall verification fails
assert not tampered_non_closing_signature_request_monitoring.verify_request_monitoring(
PARTNER_ADDRESS, ADDRESS)