BEEFY: introduce offence report system (#13564)

* Trivial adjustments to beefy and grandpa pallets

* Introduce offence report system to beefy pallet

* Minor adjustments

* Fix beefy-mmr mock

* Apply suggestions from code review

Co-authored-by: Anton <anton.kalyaev@gmail.com>

---------

Co-authored-by: Anton <anton.kalyaev@gmail.com>
This commit is contained in:
Davide Galassi
2023-03-11 19:05:55 +01:00
committed by GitHub
parent 7401383252
commit 66f3d9e237
10 changed files with 243 additions and 414 deletions
+168 -264
View File
@@ -34,179 +34,205 @@
//! that the `ValidateUnsigned` for the BEEFY pallet is used in the runtime
//! definition.
use sp_std::prelude::*;
use codec::{self as codec, Decode, Encode};
use frame_support::{
log,
traits::{Get, KeyOwnerProofSystem},
};
use frame_system::pallet_prelude::BlockNumberFor;
use sp_consensus_beefy::{EquivocationProof, ValidatorSetId};
use log::{error, info};
use sp_consensus_beefy::{EquivocationProof, ValidatorSetId, KEY_TYPE};
use sp_runtime::{
transaction_validity::{
InvalidTransaction, TransactionPriority, TransactionSource, TransactionValidity,
TransactionValidityError, ValidTransaction,
},
DispatchResult, Perbill, RuntimeAppPublic,
DispatchError, KeyTypeId, Perbill, RuntimeAppPublic,
};
use sp_session::{GetSessionNumber, GetValidatorCount};
use sp_staking::{
offence::{Kind, Offence, OffenceError, ReportOffence},
offence::{Kind, Offence, OffenceReportSystem, ReportOffence},
SessionIndex,
};
use sp_std::prelude::*;
use super::{Call, Config, Pallet, LOG_TARGET};
use super::{Call, Config, Error, Pallet, LOG_TARGET};
/// A trait with utility methods for handling equivocation reports in BEEFY.
/// The offence type is generic, and the trait provides, reporting an offence
/// triggered by a valid equivocation report, and also for creating and
/// submitting equivocation report extrinsics (useful only in offchain context).
pub trait HandleEquivocation<T: Config> {
/// The offence type used for reporting offences on valid equivocation reports.
type Offence: BeefyOffence<BlockNumberFor<T>, T::KeyOwnerIdentification>;
/// The longevity, in blocks, that the equivocation report is valid for. When using the staking
/// pallet this should be equal to the bonding duration (in blocks, not eras).
type ReportLongevity: Get<u64>;
/// Report an offence proved by the given reporters.
fn report_offence(
reporters: Vec<T::AccountId>,
offence: Self::Offence,
) -> Result<(), OffenceError>;
/// Returns true if all of the offenders at the given time slot have already been reported.
fn is_known_offence(
offenders: &[T::KeyOwnerIdentification],
time_slot: &<Self::Offence as Offence<T::KeyOwnerIdentification>>::TimeSlot,
) -> bool;
/// Create and dispatch an equivocation report extrinsic.
fn submit_unsigned_equivocation_report(
equivocation_proof: EquivocationProof<
BlockNumberFor<T>,
T::BeefyId,
<T::BeefyId as RuntimeAppPublic>::Signature,
>,
key_owner_proof: T::KeyOwnerProof,
) -> DispatchResult;
/// Fetch the current block author id, if defined.
fn block_author() -> Option<T::AccountId>;
/// A round number and set id which point on the time of an offence.
#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Encode, Decode)]
pub struct TimeSlot<N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode> {
// The order of these matters for `derive(Ord)`.
/// BEEFY Set ID.
pub set_id: ValidatorSetId,
/// Round number.
pub round: N,
}
impl<T: Config> HandleEquivocation<T> for () {
type Offence = BeefyEquivocationOffence<BlockNumberFor<T>, T::KeyOwnerIdentification>;
type ReportLongevity = ();
fn report_offence(
_reporters: Vec<T::AccountId>,
_offence: BeefyEquivocationOffence<BlockNumberFor<T>, T::KeyOwnerIdentification>,
) -> Result<(), OffenceError> {
Ok(())
}
fn is_known_offence(
_offenders: &[T::KeyOwnerIdentification],
_time_slot: &BeefyTimeSlot<BlockNumberFor<T>>,
) -> bool {
true
}
fn submit_unsigned_equivocation_report(
_equivocation_proof: EquivocationProof<
BlockNumberFor<T>,
T::BeefyId,
<T::BeefyId as RuntimeAppPublic>::Signature,
>,
_key_owner_proof: T::KeyOwnerProof,
) -> DispatchResult {
Ok(())
}
fn block_author() -> Option<T::AccountId> {
None
}
}
/// Generic equivocation handler. This type implements `HandleEquivocation`
/// using existing subsystems that are part of frame (type bounds described
/// below) and will dispatch to them directly, it's only purpose is to wire all
/// subsystems together.
pub struct EquivocationHandler<N, I, R, L, O = BeefyEquivocationOffence<N, I>> {
_phantom: sp_std::marker::PhantomData<(N, I, R, L, O)>,
}
impl<N, I, R, L, O> Default for EquivocationHandler<N, I, R, L, O> {
fn default() -> Self {
Self { _phantom: Default::default() }
}
}
impl<T, R, L, O> HandleEquivocation<T>
for EquivocationHandler<BlockNumberFor<T>, T::KeyOwnerIdentification, R, L, O>
/// BEEFY equivocation offence report.
pub struct EquivocationOffence<Offender, N>
where
// We use the authorship pallet to fetch the current block author and use
// `offchain::SendTransactionTypes` for unsigned extrinsic creation and
// submission.
T: Config + pallet_authorship::Config + frame_system::offchain::SendTransactionTypes<Call<T>>,
// A system for reporting offences after valid equivocation reports are
// processed.
R: ReportOffence<T::AccountId, T::KeyOwnerIdentification, O>,
// The longevity (in blocks) that the equivocation report is valid for. When using the staking
// pallet this should be the bonding duration.
L: Get<u64>,
// The offence type that should be used when reporting.
O: BeefyOffence<BlockNumberFor<T>, T::KeyOwnerIdentification>,
N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode,
{
type Offence = O;
type ReportLongevity = L;
/// Time slot at which this incident happened.
pub time_slot: TimeSlot<N>,
/// The session index in which the incident happened.
pub session_index: SessionIndex,
/// The size of the validator set at the time of the offence.
pub validator_set_count: u32,
/// The authority which produced this equivocation.
pub offender: Offender,
}
fn report_offence(reporters: Vec<T::AccountId>, offence: O) -> Result<(), OffenceError> {
R::report_offence(reporters, offence)
impl<Offender: Clone, N> Offence<Offender> for EquivocationOffence<Offender, N>
where
N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode,
{
const ID: Kind = *b"beefy:equivocati";
type TimeSlot = TimeSlot<N>;
fn offenders(&self) -> Vec<Offender> {
vec![self.offender.clone()]
}
fn is_known_offence(offenders: &[T::KeyOwnerIdentification], time_slot: &O::TimeSlot) -> bool {
R::is_known_offence(offenders, time_slot)
fn session_index(&self) -> SessionIndex {
self.session_index
}
fn submit_unsigned_equivocation_report(
equivocation_proof: EquivocationProof<
BlockNumberFor<T>,
T::BeefyId,
<T::BeefyId as RuntimeAppPublic>::Signature,
>,
key_owner_proof: T::KeyOwnerProof,
) -> DispatchResult {
fn validator_set_count(&self) -> u32 {
self.validator_set_count
}
fn time_slot(&self) -> Self::TimeSlot {
self.time_slot
}
// The formula is min((3k / n)^2, 1)
// where k = offenders_number and n = validators_number
fn slash_fraction(&self, offenders_count: u32) -> Perbill {
// Perbill type domain is [0, 1] by definition
Perbill::from_rational(3 * offenders_count, self.validator_set_count).square()
}
}
/// BEEFY equivocation offence report system.
///
/// This type implements `OffenceReportSystem` such that:
/// - Equivocation reports are published on-chain as unsigned extrinsic via
/// `offchain::SendTransactioinsTypes`.
/// - On-chain validity checks and processing are mostly delegated to the user provided generic
/// types implementing `KeyOwnerProofSystem` and `ReportOffence` traits.
/// - Offence reporter for unsigned transactions is fetched via the the authorship pallet.
pub struct EquivocationReportSystem<T, R, P, L>(sp_std::marker::PhantomData<(T, R, P, L)>);
/// Equivocation evidence convenience alias.
pub type EquivocationEvidenceFor<T> = (
EquivocationProof<
<T as frame_system::Config>::BlockNumber,
<T as Config>::BeefyId,
<<T as Config>::BeefyId as RuntimeAppPublic>::Signature,
>,
<T as Config>::KeyOwnerProof,
);
impl<T, R, P, L> OffenceReportSystem<Option<T::AccountId>, EquivocationEvidenceFor<T>>
for EquivocationReportSystem<T, R, P, L>
where
T: Config + pallet_authorship::Config + frame_system::offchain::SendTransactionTypes<Call<T>>,
R: ReportOffence<
T::AccountId,
P::IdentificationTuple,
EquivocationOffence<P::IdentificationTuple, T::BlockNumber>,
>,
P: KeyOwnerProofSystem<(KeyTypeId, T::BeefyId), Proof = T::KeyOwnerProof>,
P::IdentificationTuple: Clone,
L: Get<u64>,
{
type Longevity = L;
fn publish_evidence(evidence: EquivocationEvidenceFor<T>) -> Result<(), ()> {
use frame_system::offchain::SubmitTransaction;
let (equivocation_proof, key_owner_proof) = evidence;
let call = Call::report_equivocation_unsigned {
equivocation_proof: Box::new(equivocation_proof),
key_owner_proof,
};
match SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call.into()) {
Ok(()) => log::info!(target: LOG_TARGET, "Submitted BEEFY equivocation report.",),
Err(e) =>
log::error!(target: LOG_TARGET, "Error submitting equivocation report: {:?}", e,),
let res = SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call.into());
match res {
Ok(_) => info!(target: LOG_TARGET, "Submitted equivocation report."),
Err(e) => error!(target: LOG_TARGET, "Error submitting equivocation report: {:?}", e),
}
res
}
fn check_evidence(
evidence: EquivocationEvidenceFor<T>,
) -> Result<(), TransactionValidityError> {
let (equivocation_proof, key_owner_proof) = evidence;
// Check the membership proof to extract the offender's id
let key = (KEY_TYPE, equivocation_proof.offender_id().clone());
let offender = P::check_proof(key, key_owner_proof).ok_or(InvalidTransaction::BadProof)?;
// Check if the offence has already been reported, and if so then we can discard the report.
let time_slot = TimeSlot {
set_id: equivocation_proof.set_id(),
round: *equivocation_proof.round_number(),
};
if R::is_known_offence(&[offender], &time_slot) {
Err(InvalidTransaction::Stale.into())
} else {
Ok(())
}
}
fn process_evidence(
reporter: Option<T::AccountId>,
evidence: EquivocationEvidenceFor<T>,
) -> Result<(), DispatchError> {
let (equivocation_proof, key_owner_proof) = evidence;
let reporter = reporter.or_else(|| <pallet_authorship::Pallet<T>>::author());
let offender = equivocation_proof.offender_id().clone();
// We check the equivocation within the context of its set id (and
// associated session) and round. We also need to know the validator
// set count at the time of the offence since it is required to calculate
// the slash amount.
let set_id = equivocation_proof.set_id();
let round = *equivocation_proof.round_number();
let session_index = key_owner_proof.session();
let validator_set_count = key_owner_proof.validator_count();
// Validate the key ownership proof extracting the id of the offender.
let offender = P::check_proof((KEY_TYPE, offender), key_owner_proof)
.ok_or(Error::<T>::InvalidKeyOwnershipProof)?;
// Validate equivocation proof (check votes are different and signatures are valid).
if !sp_consensus_beefy::check_equivocation_proof(&equivocation_proof) {
return Err(Error::<T>::InvalidEquivocationProof.into())
}
// Check that the session id for the membership proof is within the
// bounds of the set id reported in the equivocation.
let set_id_session_index =
crate::SetIdSession::<T>::get(set_id).ok_or(Error::<T>::InvalidEquivocationProof)?;
if session_index != set_id_session_index {
return Err(Error::<T>::InvalidEquivocationProof.into())
}
let offence = EquivocationOffence {
time_slot: TimeSlot { set_id, round },
session_index,
validator_set_count,
offender,
};
R::report_offence(reporter.into_iter().collect(), offence)
.map_err(|_| Error::<T>::DuplicateOffenceReport)?;
Ok(())
}
fn block_author() -> Option<T::AccountId> {
<pallet_authorship::Pallet<T>>::author()
}
}
/// A round number and set id which point on the time of an offence.
#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Encode, Decode)]
pub struct BeefyTimeSlot<N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode> {
// The order of these matters for `derive(Ord)`.
/// BEEFY Set ID.
pub set_id: ValidatorSetId,
/// Round number.
pub round: N,
}
/// Methods for the `ValidateUnsigned` implementation:
@@ -228,11 +254,11 @@ impl<T: Config> Pallet<T> {
},
}
// check report staleness
is_known_offence::<T>(equivocation_proof, key_owner_proof)?;
let evidence = (*equivocation_proof.clone(), key_owner_proof.clone());
T::EquivocationReportSystem::check_evidence(evidence)?;
let longevity =
<T::HandleEquivocation as HandleEquivocation<T>>::ReportLongevity::get();
<T::EquivocationReportSystem as OffenceReportSystem<_, _>>::Longevity::get();
ValidTransaction::with_tag_prefix("BeefyEquivocation")
// We assign the maximum priority for any equivocation report.
@@ -254,132 +280,10 @@ impl<T: Config> Pallet<T> {
pub fn pre_dispatch(call: &Call<T>) -> Result<(), TransactionValidityError> {
if let Call::report_equivocation_unsigned { equivocation_proof, key_owner_proof } = call {
is_known_offence::<T>(equivocation_proof, key_owner_proof)
let evidence = (*equivocation_proof.clone(), key_owner_proof.clone());
T::EquivocationReportSystem::check_evidence(evidence)
} else {
Err(InvalidTransaction::Call.into())
}
}
}
fn is_known_offence<T: Config>(
equivocation_proof: &EquivocationProof<
BlockNumberFor<T>,
T::BeefyId,
<T::BeefyId as RuntimeAppPublic>::Signature,
>,
key_owner_proof: &T::KeyOwnerProof,
) -> Result<(), TransactionValidityError> {
// check the membership proof to extract the offender's id,
// equivocation validity will be fully checked during the call.
let key = (sp_consensus_beefy::KEY_TYPE, equivocation_proof.offender_id().clone());
let offender = T::KeyOwnerProofSystem::check_proof(key, key_owner_proof.clone())
.ok_or(InvalidTransaction::BadProof)?;
// check if the offence has already been reported,
// and if so then we can discard the report.
let time_slot = <T::HandleEquivocation as HandleEquivocation<T>>::Offence::new_time_slot(
equivocation_proof.set_id(),
*equivocation_proof.round_number(),
);
let is_known_offence = T::HandleEquivocation::is_known_offence(&[offender], &time_slot);
if is_known_offence {
Err(InvalidTransaction::Stale.into())
} else {
Ok(())
}
}
/// A BEEFY equivocation offence report.
pub struct BeefyEquivocationOffence<N, FullIdentification>
where
N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode,
{
/// Time slot at which this incident happened.
pub time_slot: BeefyTimeSlot<N>,
/// The session index in which the incident happened.
pub session_index: SessionIndex,
/// The size of the validator set at the time of the offence.
pub validator_set_count: u32,
/// The authority which produced this equivocation.
pub offender: FullIdentification,
}
/// An interface for types that will be used as BEEFY offences and must also
/// implement the `Offence` trait. This trait provides a constructor that is
/// provided all available data during processing of BEEFY equivocations.
pub trait BeefyOffence<N, FullIdentification>: Offence<FullIdentification>
where
N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode,
{
/// Create a new BEEFY offence using the given equivocation details.
fn new(
session_index: SessionIndex,
validator_set_count: u32,
offender: FullIdentification,
set_id: ValidatorSetId,
round: N,
) -> Self;
/// Create a new BEEFY offence time slot.
fn new_time_slot(set_id: ValidatorSetId, round: N) -> Self::TimeSlot;
}
impl<N, FullIdentification: Clone> BeefyOffence<N, FullIdentification>
for BeefyEquivocationOffence<N, FullIdentification>
where
N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode,
{
fn new(
session_index: SessionIndex,
validator_set_count: u32,
offender: FullIdentification,
set_id: ValidatorSetId,
round: N,
) -> Self {
BeefyEquivocationOffence {
session_index,
validator_set_count,
offender,
time_slot: BeefyTimeSlot { set_id, round },
}
}
fn new_time_slot(set_id: ValidatorSetId, round: N) -> Self::TimeSlot {
BeefyTimeSlot { set_id, round }
}
}
impl<N, FullIdentification: Clone> Offence<FullIdentification>
for BeefyEquivocationOffence<N, FullIdentification>
where
N: Copy + Clone + PartialOrd + Ord + Eq + PartialEq + Encode + Decode,
{
const ID: Kind = *b"beefy:equivocati";
type TimeSlot = BeefyTimeSlot<N>;
fn offenders(&self) -> Vec<FullIdentification> {
vec![self.offender.clone()]
}
fn session_index(&self) -> SessionIndex {
self.session_index
}
fn validator_set_count(&self) -> u32 {
self.validator_set_count
}
fn time_slot(&self) -> Self::TimeSlot {
self.time_slot
}
fn slash_fraction(&self, offenders_count: u32) -> Perbill {
// the formula is min((3k / n)^2, 1)
let x = Perbill::from_rational(3 * offenders_count, self.validator_set_count);
// _ ^ 2
x.square()
}
}