Files
nutshell/cashu/mint/verification.py
callebtc 6a0a370ba5 Mint: table locks (#566)
* clean up db

* db: table lock

* db.table_with_schema

* fix encrypt.py

* postgres nowait

* add timeout to lock

* melt quote state in db

* kinda working

* kinda working with postgres

* remove dispose

* getting there

* porperly clean up db for tests

* faster tests

* configure connection pooling

* try github with connection pool

* invoice dispatcher does not lock db

* fakewallet: pay_if_regtest waits

* pay fakewallet invoices

* add more

* faster

* slower

* pay_if_regtest async

* do not lock the invoice dispatcher

* test: do I get disk I/O errors if we disable the invoice_callback_dispatcher?

* fix fake so it workss without a callback dispatchert

* test on github

* readd tasks

* refactor

* increase time for lock invoice disatcher

* try avoiding a race

* remove task

* github actions: test regtest with postgres

* mint per module

* no connection pool for testing

* enable pool

* do not resend paid event

* reuse connection

* close db connections

* sessions

* enable debug

* dispose engine

* disable connection pool for tests

* enable connection pool for postgres only

* clean up shutdown routine

* remove wait for lightning fakewallet lightning invoice

* cancel invoice listener tasks on shutdown

* fakewallet conftest: decrease outgoing delay

* delay payment and set postgres only if needed

* disable fail fast for regtest

* clean up regtest.yml

* change order of tests_db.py

* row-specific mint_quote locking

* refactor

* fix lock statement

* refactor swap

* refactor

* remove psycopg2

* add connection string example to .env.example

* remove unnecessary pay

* shorter sleep in test_wallet_subscription_swap
2024-07-08 18:05:57 +02:00

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from typing import Dict, List, Literal, Optional, Tuple, Union
from loguru import logger
from ..core.base import (
BlindedMessage,
BlindedSignature,
Method,
MintKeyset,
Proof,
Unit,
)
from ..core.crypto import b_dhke
from ..core.crypto.secp import PublicKey
from ..core.db import Connection, Database
from ..core.errors import (
NoSecretInProofsError,
NotAllowedError,
SecretTooLongError,
TokenAlreadySpentError,
TransactionError,
TransactionUnitError,
)
from ..core.settings import settings
from ..lightning.base import LightningBackend
from ..mint.crud import LedgerCrud
from .conditions import LedgerSpendingConditions
from .protocols import SupportsBackends, SupportsDb, SupportsKeysets
class LedgerVerification(
LedgerSpendingConditions, SupportsKeysets, SupportsDb, SupportsBackends
):
"""Verification functions for the ledger."""
keyset: MintKeyset
keysets: Dict[str, MintKeyset]
crud: LedgerCrud
db: Database
lightning: Dict[Unit, LightningBackend]
async def verify_inputs_and_outputs(
self,
*,
proofs: List[Proof],
outputs: Optional[List[BlindedMessage]] = None,
conn: Optional[Connection] = None,
):
"""Checks all proofs and outputs for validity.
Args:
proofs (List[Proof]): List of proofs to check.
outputs (Optional[List[BlindedMessage]], optional): List of outputs to check.
Must be provided for a swap but not for a melt. Defaults to None.
conn (Optional[Connection], optional): Database connection. Defaults to None.
Raises:
Exception: Scripts did not validate.
Exception: Criteria for provided secrets not met.
Exception: Duplicate proofs provided.
Exception: BDHKE verification failed.
"""
# Verify inputs
if not proofs:
raise TransactionError("no proofs provided.")
# Verify proofs are spendable
if not len(await self._get_proofs_spent([p.Y for p in proofs], conn)) == 0:
raise TokenAlreadySpentError()
# Verify amounts of inputs
if not all([self._verify_amount(p.amount) for p in proofs]):
raise TransactionError("invalid amount.")
# Verify secret criteria
if not all([self._verify_secret_criteria(p) for p in proofs]):
raise TransactionError("secrets do not match criteria.")
# verify that only unique proofs were used
if not self._verify_no_duplicate_proofs(proofs):
raise TransactionError("duplicate proofs.")
# Verify ecash signatures
if not all([self._verify_proof_bdhke(p) for p in proofs]):
raise TransactionError("could not verify proofs.")
# Verify input spending conditions
if not all([self._verify_input_spending_conditions(p) for p in proofs]):
raise TransactionError("validation of input spending conditions failed.")
if outputs is None:
# If no outputs are provided, we are melting
return
# Verify input and output amounts
self._verify_equation_balanced(proofs, outputs)
# Verify outputs
await self._verify_outputs(outputs, conn=conn)
# Verify inputs and outputs together
if not self._verify_input_output_amounts(proofs, outputs):
raise TransactionError("input amounts less than output.")
# Verify that input keyset units are the same as output keyset unit
# We have previously verified that all outputs have the same keyset id in `_verify_outputs`
assert outputs[0].id, "output id not set"
if not all(
[
self.keysets[p.id].unit == self.keysets[outputs[0].id].unit
for p in proofs
]
):
raise TransactionError("input and output keysets have different units.")
# Verify output spending conditions
if outputs and not self._verify_output_spending_conditions(proofs, outputs):
raise TransactionError("validation of output spending conditions failed.")
async def _verify_outputs(
self,
outputs: List[BlindedMessage],
skip_amount_check=False,
conn: Optional[Connection] = None,
):
"""Verify that the outputs are valid."""
logger.trace(f"Verifying {len(outputs)} outputs.")
if not outputs:
raise TransactionError("no outputs provided.")
# Verify all outputs have the same keyset id
if not all([o.id == outputs[0].id for o in outputs]):
raise TransactionError("outputs have different keyset ids.")
# Verify that the keyset id is known and active
if outputs[0].id not in self.keysets:
raise TransactionError("keyset id unknown.")
if not self.keysets[outputs[0].id].active:
raise TransactionError("keyset id inactive.")
# Verify amounts of outputs
# we skip the amount check for NUT-8 change outputs (which can have amount 0)
if not skip_amount_check:
if not all([self._verify_amount(o.amount) for o in outputs]):
raise TransactionError("invalid amount.")
# verify that only unique outputs were used
if not self._verify_no_duplicate_outputs(outputs):
raise TransactionError("duplicate outputs.")
# verify that outputs have not been signed previously
signed_before = await self._check_outputs_issued_before(outputs, conn)
if any(signed_before):
raise TransactionError("outputs have already been signed before.")
logger.trace(f"Verified {len(outputs)} outputs.")
async def _check_outputs_issued_before(
self,
outputs: List[BlindedMessage],
conn: Optional[Connection] = None,
) -> List[bool]:
"""Checks whether the provided outputs have previously been signed by the mint
(which would lead to a duplication error later when trying to store these outputs again).
Args:
outputs (List[BlindedMessage]): Outputs to check
Returns:
result (List[bool]): Whether outputs are already present in the database.
"""
result = []
async with self.db.get_connection(conn) as conn:
for output in outputs:
promise = await self.crud.get_promise(
b_=output.B_, db=self.db, conn=conn
)
result.append(False if promise is None else True)
return result
async def _get_proofs_spent(
self, Ys: List[str], conn: Optional[Connection] = None
) -> Dict[str, Proof]:
"""Returns a dictionary of all proofs that are spent.
The key is the Y=h2c(secret) and the value is the proof.
"""
proofs_spent_dict: Dict[str, Proof] = {}
# check used secrets in database
async with self.db.get_connection(conn=conn) as conn:
for Y in Ys:
spent_proof = await self.crud.get_proof_used(db=self.db, Y=Y, conn=conn)
if spent_proof:
proofs_spent_dict[Y] = spent_proof
return proofs_spent_dict
def _verify_secret_criteria(self, proof: Proof) -> Literal[True]:
"""Verifies that a secret is present and is not too long (DOS prevention)."""
if proof.secret is None or proof.secret == "":
raise NoSecretInProofsError()
if len(proof.secret) > settings.mint_max_secret_length:
raise SecretTooLongError(
f"secret too long. max: {settings.mint_max_secret_length}"
)
return True
def _verify_proof_bdhke(self, proof: Proof) -> bool:
"""Verifies that the proof of promise was issued by this ledger."""
assert proof.id in self.keysets, f"keyset {proof.id} unknown"
logger.trace(
f"Validating proof {proof.secret} with keyset"
f" {self.keysets[proof.id].id}."
)
# use the appropriate active keyset for this proof.id
private_key_amount = self.keysets[proof.id].private_keys[proof.amount]
C = PublicKey(bytes.fromhex(proof.C), raw=True)
valid = b_dhke.verify(private_key_amount, C, proof.secret)
if valid:
logger.trace("Proof verified.")
else:
logger.trace(f"Proof verification failed for {proof.secret} {proof.C}.")
return valid
def _verify_input_output_amounts(
self, inputs: List[Proof], outputs: List[BlindedMessage]
) -> bool:
"""Verifies that inputs have at least the same amount as outputs"""
input_amount = sum([p.amount for p in inputs])
output_amount = sum([o.amount for o in outputs])
return input_amount >= output_amount
def _verify_no_duplicate_proofs(self, proofs: List[Proof]) -> bool:
secrets = [p.secret for p in proofs]
if len(secrets) != len(list(set(secrets))):
return False
return True
def _verify_no_duplicate_outputs(self, outputs: List[BlindedMessage]) -> bool:
B_s = [od.B_ for od in outputs]
if len(B_s) != len(list(set(B_s))):
return False
return True
def _verify_amount(self, amount: int) -> int:
"""Any amount used should be positive and not larger than 2^MAX_ORDER."""
valid = amount > 0 and amount < 2**settings.max_order
if not valid:
raise NotAllowedError("invalid amount: " + str(amount))
return amount
def _verify_units_match(
self,
proofs: List[Proof],
outs: Union[List[BlindedSignature], List[BlindedMessage]],
) -> Unit:
"""Verifies that the units of the inputs and outputs match."""
units_proofs = [self.keysets[p.id].unit for p in proofs]
units_outputs = [self.keysets[o.id].unit for o in outs if o.id]
if not len(set(units_proofs)) == 1:
raise TransactionUnitError("inputs have different units.")
if not len(set(units_outputs)) == 1:
raise TransactionUnitError("outputs have different units.")
if not units_proofs[0] == units_outputs[0]:
raise TransactionUnitError("input and output keysets have different units.")
return units_proofs[0]
def get_fees_for_proofs(self, proofs: List[Proof]) -> int:
if not len(set([self.keysets[p.id].unit for p in proofs])) == 1:
raise TransactionUnitError("inputs have different units.")
fee = (sum([self.keysets[p.id].input_fee_ppk for p in proofs]) + 999) // 1000
return fee
def _verify_equation_balanced(
self,
proofs: List[Proof],
outs: List[BlindedMessage],
) -> None:
"""Verify that Σinputs - Σoutputs = 0.
Outputs can be BlindedSignature or BlindedMessage.
"""
if not proofs:
raise TransactionError("no proofs provided.")
if not outs:
raise TransactionError("no outputs provided.")
_ = self._verify_units_match(proofs, outs)
sum_inputs = sum(self._verify_amount(p.amount) for p in proofs)
fees_inputs = self.get_fees_for_proofs(proofs)
sum_outputs = sum(self._verify_amount(p.amount) for p in outs)
if not sum_outputs + fees_inputs - sum_inputs == 0:
raise TransactionError(
f"inputs ({sum_inputs}) - fees ({fees_inputs}) vs outputs ({sum_outputs}) are not balanced."
)
def _verify_and_get_unit_method(
self, unit_str: str, method_str: str
) -> Tuple[Unit, Method]:
"""Verify that the unit is supported by the ledger."""
method = Method[method_str]
unit = Unit[unit_str]
if not any([unit == k.unit for k in self.keysets.values()]):
raise NotAllowedError(f"unit '{unit.name}' not supported in any keyset.")
if not self.backends.get(method) or unit not in self.backends[method]:
raise NotAllowedError(
f"no support for method '{method.name}' with unit '{unit.name}'."
)
return unit, method