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931daa40d7
## Issue Addressed Resolves #2545 ## Proposed Changes Adds the long-overdue EF tests for fork choice. Although we had pretty good coverage via other implementations that closely followed our approach, it is nonetheless important for us to implement these tests too. During testing I found that we were using a hard-coded `SAFE_SLOTS_TO_UPDATE_JUSTIFIED` value rather than one from the `ChainSpec`. This caused a failure during a minimal preset test. This doesn't represent a risk to mainnet or testnets, since the hard-coded value matched the mainnet preset. ## Failing Cases There is one failing case which is presently marked as `SkippedKnownFailure`: ``` case 4 ("new_finalized_slot_is_justified_checkpoint_ancestor") from /home/paul/development/lighthouse/testing/ef_tests/consensus-spec-tests/tests/minimal/phase0/fork_choice/on_block/pyspec_tests/new_finalized_slot_is_justified_checkpoint_ancestor failed with NotEqual: head check failed: Got Head { slot: Slot(40), root: 0x9183dbaed4191a862bd307d476e687277fc08469fc38618699863333487703e7 } | Expected Head { slot: Slot(24), root: 0x105b49b51bf7103c182aa58860b039550a89c05a4675992e2af703bd02c84570 } ``` This failure is due to #2741. It's not a particularly high priority issue at the moment, so we fix it after merging this PR.
1265 lines
48 KiB
Rust
1265 lines
48 KiB
Rust
//! Provides verification for the following attestations:
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//!
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//! - "Unaggregated" `Attestation` received from either gossip or the HTTP API.
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//! - "Aggregated" `SignedAggregateAndProof` received from gossip or the HTTP API.
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//!
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//! For clarity, we define:
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//!
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//! - Unaggregated: an `Attestation` object that has exactly one aggregation bit set.
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//! - Aggregated: a `SignedAggregateAndProof` which has zero or more signatures.
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//! - Note: "zero or more" may soon change to "one or more".
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//!
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//! Similar to the `crate::block_verification` module, we try to avoid doing duplicate verification
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//! work as an attestation passes through different stages of verification. We represent these
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//! different stages of verification with wrapper types. These wrapper-types flow in a particular
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//! pattern:
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//!
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//! ```ignore
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//! types::Attestation types::SignedAggregateAndProof
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//! | |
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//! ▼ ▼
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//! IndexedUnaggregatedAttestation IndexedAggregatedAttestation
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//! | |
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//! VerifiedUnaggregatedAttestation VerifiedAggregatedAttestation
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//! | |
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//! -------------------------------------
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//! |
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//! ▼
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//! impl VerifiedAttestation
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//! ```
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mod batch;
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use crate::{
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beacon_chain::{MAXIMUM_GOSSIP_CLOCK_DISPARITY, VALIDATOR_PUBKEY_CACHE_LOCK_TIMEOUT},
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metrics,
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observed_aggregates::ObserveOutcome,
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observed_attesters::Error as ObservedAttestersError,
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BeaconChain, BeaconChainError, BeaconChainTypes,
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};
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use bls::verify_signature_sets;
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use proto_array::Block as ProtoBlock;
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use slog::debug;
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use slot_clock::SlotClock;
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use state_processing::{
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common::get_indexed_attestation,
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per_block_processing::errors::AttestationValidationError,
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signature_sets::{
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indexed_attestation_signature_set_from_pubkeys,
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signed_aggregate_selection_proof_signature_set, signed_aggregate_signature_set,
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},
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};
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use std::borrow::Cow;
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use strum::AsRefStr;
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use tree_hash::TreeHash;
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use types::{
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Attestation, BeaconCommittee, CommitteeIndex, Epoch, EthSpec, Hash256, IndexedAttestation,
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SelectionProof, SignedAggregateAndProof, Slot, SubnetId,
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};
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pub use batch::{batch_verify_aggregated_attestations, batch_verify_unaggregated_attestations};
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/// Returned when an attestation was not successfully verified. It might not have been verified for
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/// two reasons:
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///
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/// - The attestation is malformed or inappropriate for the context (indicated by all variants
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/// other than `BeaconChainError`).
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/// - The application encountered an internal error whilst attempting to determine validity
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/// (the `BeaconChainError` variant)
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#[derive(Debug, AsRefStr)]
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pub enum Error {
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/// The attestation is from a slot that is later than the current slot (with respect to the
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/// gossip clock disparity).
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///
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/// ## Peer scoring
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///
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/// Assuming the local clock is correct, the peer has sent an invalid message.
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FutureSlot {
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attestation_slot: Slot,
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latest_permissible_slot: Slot,
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},
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/// The attestation is from a slot that is prior to the earliest permissible slot (with
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/// respect to the gossip clock disparity).
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///
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/// ## Peer scoring
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///
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/// Assuming the local clock is correct, the peer has sent an invalid message.
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PastSlot {
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attestation_slot: Slot,
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earliest_permissible_slot: Slot,
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},
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/// The attestations aggregation bits were empty when they shouldn't be.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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EmptyAggregationBitfield,
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/// The `selection_proof` on the aggregate attestation does not elect it as an aggregator.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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InvalidSelectionProof { aggregator_index: u64 },
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/// The `selection_proof` on the aggregate attestation selects it as a validator, however the
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/// aggregator index is not in the committee for that attestation.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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AggregatorNotInCommittee { aggregator_index: u64 },
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/// The aggregator index refers to a validator index that we have not seen.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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AggregatorPubkeyUnknown(u64),
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/// The attestation has been seen before; either in a block, on the gossip network or from a
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/// local validator.
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///
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/// ## Peer scoring
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///
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/// It's unclear if this attestation is valid, however we have already observed it and do not
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/// need to observe it again.
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AttestationAlreadyKnown(Hash256),
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/// There has already been an aggregation observed for this validator, we refuse to process a
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/// second.
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///
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/// ## Peer scoring
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///
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/// It's unclear if this attestation is valid, however we have already observed an aggregate
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/// attestation from this validator for this epoch and should not observe another.
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AggregatorAlreadyKnown(u64),
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/// The aggregator index is higher than the maximum possible validator count.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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ValidatorIndexTooHigh(usize),
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/// The `attestation.data.beacon_block_root` block is unknown.
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///
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/// ## Peer scoring
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///
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/// The attestation points to a block we have not yet imported. It's unclear if the attestation
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/// is valid or not.
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UnknownHeadBlock { beacon_block_root: Hash256 },
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/// The `attestation.data.slot` is not from the same epoch as `data.target.epoch`.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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BadTargetEpoch,
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/// The target root of the attestation points to a block that we have not verified.
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///
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/// This is invalid behaviour whilst we first check for `UnknownHeadBlock`.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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UnknownTargetRoot(Hash256),
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/// A signature on the attestation is invalid.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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InvalidSignature,
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/// There is no committee for the slot and committee index of this attestation and the
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/// attestation should not have been produced.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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NoCommitteeForSlotAndIndex { slot: Slot, index: CommitteeIndex },
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/// The unaggregated attestation doesn't have only one aggregation bit set.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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NotExactlyOneAggregationBitSet(usize),
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/// We have already observed an attestation for the `validator_index` and refuse to process
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/// another.
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///
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/// ## Peer scoring
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///
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/// It's unclear if this attestation is valid, however we have already observed a
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/// single-participant attestation from this validator for this epoch and should not observe
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/// another.
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PriorAttestationKnown { validator_index: u64, epoch: Epoch },
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/// The attestation is for an epoch in the future (with respect to the gossip clock disparity).
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///
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/// ## Peer scoring
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///
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/// Assuming the local clock is correct, the peer has sent an invalid message.
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FutureEpoch {
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attestation_epoch: Epoch,
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current_epoch: Epoch,
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},
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/// The attestation is for an epoch in the past (with respect to the gossip clock disparity).
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///
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/// ## Peer scoring
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///
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/// Assuming the local clock is correct, the peer has sent an invalid message.
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PastEpoch {
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attestation_epoch: Epoch,
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current_epoch: Epoch,
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},
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/// The attestation is attesting to a state that is later than itself. (Viz., attesting to the
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/// future).
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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AttestsToFutureBlock { block: Slot, attestation: Slot },
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/// The attestation was received on an invalid attestation subnet.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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InvalidSubnetId {
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received: SubnetId,
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expected: SubnetId,
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},
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/// The attestation failed the `state_processing` verification stage.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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Invalid(AttestationValidationError),
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/// The attestation head block is too far behind the attestation slot, causing many skip slots.
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/// This is deemed a DoS risk.
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TooManySkippedSlots {
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head_block_slot: Slot,
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attestation_slot: Slot,
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},
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/// The attestation has an invalid target epoch.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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InvalidTargetEpoch { slot: Slot, epoch: Epoch },
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/// The attestation references an invalid target block.
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///
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/// ## Peer scoring
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///
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/// The peer has sent an invalid message.
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InvalidTargetRoot {
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attestation: Hash256,
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expected: Option<Hash256>,
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},
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/// There was an error whilst processing the attestation. It is not known if it is valid or invalid.
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///
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/// ## Peer scoring
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///
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/// We were unable to process this attestation due to an internal error. It's unclear if the
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/// attestation is valid.
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BeaconChainError(BeaconChainError),
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}
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impl From<BeaconChainError> for Error {
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fn from(e: BeaconChainError) -> Self {
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Error::BeaconChainError(e)
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}
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}
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/// Used to avoid double-checking signatures.
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#[derive(Copy, Clone)]
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enum CheckAttestationSignature {
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Yes,
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No,
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}
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/// Wraps a `SignedAggregateAndProof` that has been verified up until the point that an
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/// `IndexedAttestation` can be derived.
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///
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/// These attestations have *not* undergone signature verification.
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struct IndexedAggregatedAttestation<'a, T: BeaconChainTypes> {
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signed_aggregate: &'a SignedAggregateAndProof<T::EthSpec>,
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indexed_attestation: IndexedAttestation<T::EthSpec>,
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attestation_root: Hash256,
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}
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/// Wraps a `Attestation` that has been verified up until the point that an `IndexedAttestation` can
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/// be derived.
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///
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/// These attestations have *not* undergone signature verification.
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struct IndexedUnaggregatedAttestation<'a, T: BeaconChainTypes> {
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attestation: &'a Attestation<T::EthSpec>,
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indexed_attestation: IndexedAttestation<T::EthSpec>,
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subnet_id: SubnetId,
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validator_index: u64,
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}
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/// Wraps a `SignedAggregateAndProof` that has been fully verified for propagation on the gossip
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/// network.
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pub struct VerifiedAggregatedAttestation<'a, T: BeaconChainTypes> {
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signed_aggregate: &'a SignedAggregateAndProof<T::EthSpec>,
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indexed_attestation: IndexedAttestation<T::EthSpec>,
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}
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impl<'a, T: BeaconChainTypes> VerifiedAggregatedAttestation<'a, T> {
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pub fn into_indexed_attestation(self) -> IndexedAttestation<T::EthSpec> {
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self.indexed_attestation
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}
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}
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/// Wraps an `Attestation` that has been fully verified for propagation on the gossip network.
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pub struct VerifiedUnaggregatedAttestation<'a, T: BeaconChainTypes> {
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attestation: &'a Attestation<T::EthSpec>,
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indexed_attestation: IndexedAttestation<T::EthSpec>,
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subnet_id: SubnetId,
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}
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impl<'a, T: BeaconChainTypes> VerifiedUnaggregatedAttestation<'a, T> {
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pub fn into_indexed_attestation(self) -> IndexedAttestation<T::EthSpec> {
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self.indexed_attestation
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}
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}
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/// Custom `Clone` implementation is to avoid the restrictive trait bounds applied by the usual derive
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/// macro.
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impl<'a, T: BeaconChainTypes> Clone for IndexedUnaggregatedAttestation<'a, T> {
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fn clone(&self) -> Self {
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Self {
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attestation: self.attestation,
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indexed_attestation: self.indexed_attestation.clone(),
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subnet_id: self.subnet_id,
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validator_index: self.validator_index,
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}
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}
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}
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/// A helper trait implemented on wrapper types that can be progressed to a state where they can be
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/// verified for application to fork choice.
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pub trait VerifiedAttestation<T: BeaconChainTypes> {
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fn attestation(&self) -> &Attestation<T::EthSpec>;
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fn indexed_attestation(&self) -> &IndexedAttestation<T::EthSpec>;
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}
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impl<'a, T: BeaconChainTypes> VerifiedAttestation<T> for VerifiedAggregatedAttestation<'a, T> {
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fn attestation(&self) -> &Attestation<T::EthSpec> {
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self.attestation()
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}
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fn indexed_attestation(&self) -> &IndexedAttestation<T::EthSpec> {
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&self.indexed_attestation
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}
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}
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impl<'a, T: BeaconChainTypes> VerifiedAttestation<T> for VerifiedUnaggregatedAttestation<'a, T> {
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fn attestation(&self) -> &Attestation<T::EthSpec> {
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self.attestation
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}
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fn indexed_attestation(&self) -> &IndexedAttestation<T::EthSpec> {
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&self.indexed_attestation
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}
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}
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/// Information about invalid attestations which might still be slashable despite being invalid.
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pub enum AttestationSlashInfo<'a, T: BeaconChainTypes, TErr> {
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/// The attestation is invalid, but its signature wasn't checked.
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SignatureNotChecked(&'a Attestation<T::EthSpec>, TErr),
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/// As for `SignatureNotChecked`, but we know the `IndexedAttestation`.
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SignatureNotCheckedIndexed(IndexedAttestation<T::EthSpec>, TErr),
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/// The attestation's signature is invalid, so it will never be slashable.
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SignatureInvalid(TErr),
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/// The signature is valid but the attestation is invalid in some other way.
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SignatureValid(IndexedAttestation<T::EthSpec>, TErr),
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}
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/// After processing an attestation normally, optionally process it further for the slasher.
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///
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/// This maps an `AttestationSlashInfo` error back into a regular `Error`, performing signature
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/// checks on attestations that failed verification for other reasons.
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///
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/// No substantial extra work will be done if there is no slasher configured.
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fn process_slash_info<T: BeaconChainTypes>(
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slash_info: AttestationSlashInfo<T, Error>,
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chain: &BeaconChain<T>,
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) -> Error {
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use AttestationSlashInfo::*;
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if let Some(slasher) = chain.slasher.as_ref() {
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let (indexed_attestation, check_signature, err) = match slash_info {
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SignatureNotChecked(attestation, err) => {
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match obtain_indexed_attestation_and_committees_per_slot(chain, attestation) {
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Ok((indexed, _)) => (indexed, true, err),
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Err(e) => {
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debug!(
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chain.log,
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"Unable to obtain indexed form of attestation for slasher";
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"attestation_root" => format!("{:?}", attestation.tree_hash_root()),
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"error" => format!("{:?}", e)
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);
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return err;
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}
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}
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}
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SignatureNotCheckedIndexed(indexed, err) => (indexed, true, err),
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SignatureInvalid(e) => return e,
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SignatureValid(indexed, err) => (indexed, false, err),
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};
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if check_signature {
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if let Err(e) = verify_attestation_signature(chain, &indexed_attestation) {
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debug!(
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chain.log,
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"Signature verification for slasher failed";
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"error" => format!("{:?}", e),
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);
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return err;
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}
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}
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// Supply to slasher.
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slasher.accept_attestation(indexed_attestation);
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err
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} else {
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match slash_info {
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SignatureNotChecked(_, e)
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| SignatureNotCheckedIndexed(_, e)
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| SignatureInvalid(e)
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| SignatureValid(_, e) => e,
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}
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}
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}
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impl<'a, T: BeaconChainTypes> IndexedAggregatedAttestation<'a, T> {
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/// Returns `Ok(Self)` if the `signed_aggregate` is valid to be (re)published on the gossip
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/// network.
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pub fn verify(
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signed_aggregate: &'a SignedAggregateAndProof<T::EthSpec>,
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chain: &BeaconChain<T>,
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) -> Result<Self, Error> {
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Self::verify_slashable(signed_aggregate, chain)
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.map(|verified_aggregate| {
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if let Some(slasher) = chain.slasher.as_ref() {
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slasher.accept_attestation(verified_aggregate.indexed_attestation.clone());
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}
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verified_aggregate
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})
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.map_err(|slash_info| process_slash_info(slash_info, chain))
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}
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/// Run the checks that happen before an indexed attestation is constructed.
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fn verify_early_checks(
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signed_aggregate: &SignedAggregateAndProof<T::EthSpec>,
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chain: &BeaconChain<T>,
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) -> Result<Hash256, Error> {
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let attestation = &signed_aggregate.message.aggregate;
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|
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// Ensure attestation is within the last ATTESTATION_PROPAGATION_SLOT_RANGE slots (within a
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// MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance).
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//
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// We do not queue future attestations for later processing.
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verify_propagation_slot_range(chain, attestation)?;
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|
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// Check the attestation's epoch matches its target.
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if attestation.data.slot.epoch(T::EthSpec::slots_per_epoch())
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!= attestation.data.target.epoch
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{
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return Err(Error::InvalidTargetEpoch {
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slot: attestation.data.slot,
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epoch: attestation.data.target.epoch,
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});
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}
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// Ensure the valid aggregated attestation has not already been seen locally.
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let attestation_root = attestation.tree_hash_root();
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if chain
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.observed_attestations
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.write()
|
|
.is_known(attestation, attestation_root)
|
|
.map_err(|e| Error::BeaconChainError(e.into()))?
|
|
{
|
|
return Err(Error::AttestationAlreadyKnown(attestation_root));
|
|
}
|
|
|
|
let aggregator_index = signed_aggregate.message.aggregator_index;
|
|
|
|
// Ensure there has been no other observed aggregate for the given `aggregator_index`.
|
|
//
|
|
// Note: do not observe yet, only observe once the attestation has been verified.
|
|
match chain
|
|
.observed_aggregators
|
|
.read()
|
|
.validator_has_been_observed(attestation.data.target.epoch, aggregator_index as usize)
|
|
{
|
|
Ok(true) => Err(Error::AggregatorAlreadyKnown(aggregator_index)),
|
|
Ok(false) => Ok(()),
|
|
Err(ObservedAttestersError::ValidatorIndexTooHigh(i)) => {
|
|
Err(Error::ValidatorIndexTooHigh(i))
|
|
}
|
|
Err(e) => Err(BeaconChainError::from(e).into()),
|
|
}?;
|
|
|
|
// Ensure the block being voted for (attestation.data.beacon_block_root) passes validation.
|
|
// Don't enforce the skip slot restriction for aggregates.
|
|
//
|
|
// This indirectly checks to see if the `attestation.data.beacon_block_root` is in our fork
|
|
// choice. Any known, non-finalized, processed block should be in fork choice, so this
|
|
// check immediately filters out attestations that attest to a block that has not been
|
|
// processed.
|
|
//
|
|
// Attestations must be for a known block. If the block is unknown, we simply drop the
|
|
// attestation and do not delay consideration for later.
|
|
let head_block = verify_head_block_is_known(chain, attestation, None)?;
|
|
|
|
// Check the attestation target root is consistent with the head root.
|
|
//
|
|
// This check is not in the specification, however we guard against it since it opens us up
|
|
// to weird edge cases during verification.
|
|
//
|
|
// Whilst this attestation *technically* could be used to add value to a block, it is
|
|
// invalid in the spirit of the protocol. Here we choose safety over profit.
|
|
verify_attestation_target_root::<T::EthSpec>(&head_block, attestation)?;
|
|
|
|
// Ensure that the attestation has participants.
|
|
if attestation.aggregation_bits.is_zero() {
|
|
Err(Error::EmptyAggregationBitfield)
|
|
} else {
|
|
Ok(attestation_root)
|
|
}
|
|
}
|
|
|
|
/// Verify the attestation, producing extra information about whether it might be slashable.
|
|
pub fn verify_slashable(
|
|
signed_aggregate: &'a SignedAggregateAndProof<T::EthSpec>,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<Self, AttestationSlashInfo<'a, T, Error>> {
|
|
use AttestationSlashInfo::*;
|
|
|
|
let attestation = &signed_aggregate.message.aggregate;
|
|
let aggregator_index = signed_aggregate.message.aggregator_index;
|
|
let attestation_root = match Self::verify_early_checks(signed_aggregate, chain) {
|
|
Ok(root) => root,
|
|
Err(e) => return Err(SignatureNotChecked(&signed_aggregate.message.aggregate, e)),
|
|
};
|
|
|
|
let indexed_attestation =
|
|
match map_attestation_committee(chain, attestation, |(committee, _)| {
|
|
// Note: this clones the signature which is known to be a relatively slow operation.
|
|
//
|
|
// Future optimizations should remove this clone.
|
|
let selection_proof =
|
|
SelectionProof::from(signed_aggregate.message.selection_proof.clone());
|
|
|
|
if !selection_proof
|
|
.is_aggregator(committee.committee.len(), &chain.spec)
|
|
.map_err(|e| Error::BeaconChainError(e.into()))?
|
|
{
|
|
return Err(Error::InvalidSelectionProof { aggregator_index });
|
|
}
|
|
|
|
// Ensure the aggregator is a member of the committee for which it is aggregating.
|
|
if !committee.committee.contains(&(aggregator_index as usize)) {
|
|
return Err(Error::AggregatorNotInCommittee { aggregator_index });
|
|
}
|
|
|
|
get_indexed_attestation(committee.committee, attestation)
|
|
.map_err(|e| BeaconChainError::from(e).into())
|
|
}) {
|
|
Ok(indexed_attestation) => indexed_attestation,
|
|
Err(e) => return Err(SignatureNotChecked(&signed_aggregate.message.aggregate, e)),
|
|
};
|
|
|
|
Ok(IndexedAggregatedAttestation {
|
|
signed_aggregate,
|
|
indexed_attestation,
|
|
attestation_root,
|
|
})
|
|
}
|
|
}
|
|
|
|
impl<'a, T: BeaconChainTypes> VerifiedAggregatedAttestation<'a, T> {
|
|
/// Run the checks that happen after the indexed attestation and signature have been checked.
|
|
fn verify_late_checks(
|
|
signed_aggregate: &SignedAggregateAndProof<T::EthSpec>,
|
|
attestation_root: Hash256,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<(), Error> {
|
|
let attestation = &signed_aggregate.message.aggregate;
|
|
let aggregator_index = signed_aggregate.message.aggregator_index;
|
|
|
|
// Observe the valid attestation so we do not re-process it.
|
|
//
|
|
// It's important to double check that the attestation is not already known, otherwise two
|
|
// attestations processed at the same time could be published.
|
|
if let ObserveOutcome::AlreadyKnown = chain
|
|
.observed_attestations
|
|
.write()
|
|
.observe_item(attestation, Some(attestation_root))
|
|
.map_err(|e| Error::BeaconChainError(e.into()))?
|
|
{
|
|
return Err(Error::AttestationAlreadyKnown(attestation_root));
|
|
}
|
|
|
|
// Observe the aggregator so we don't process another aggregate from them.
|
|
//
|
|
// It's important to double check that the attestation is not already known, otherwise two
|
|
// attestations processed at the same time could be published.
|
|
if chain
|
|
.observed_aggregators
|
|
.write()
|
|
.observe_validator(attestation.data.target.epoch, aggregator_index as usize)
|
|
.map_err(BeaconChainError::from)?
|
|
{
|
|
return Err(Error::PriorAttestationKnown {
|
|
validator_index: aggregator_index,
|
|
epoch: attestation.data.target.epoch,
|
|
});
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
/// Verify the `signed_aggregate`.
|
|
pub fn verify(
|
|
signed_aggregate: &'a SignedAggregateAndProof<T::EthSpec>,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<Self, Error> {
|
|
let indexed = IndexedAggregatedAttestation::verify(signed_aggregate, chain)?;
|
|
Self::from_indexed(indexed, chain, CheckAttestationSignature::Yes)
|
|
}
|
|
|
|
/// Complete the verification of an indexed attestation.
|
|
fn from_indexed(
|
|
signed_aggregate: IndexedAggregatedAttestation<'a, T>,
|
|
chain: &BeaconChain<T>,
|
|
check_signature: CheckAttestationSignature,
|
|
) -> Result<Self, Error> {
|
|
Self::verify_slashable(signed_aggregate, chain, check_signature)
|
|
.map(|verified_aggregate| verified_aggregate.apply_to_slasher(chain))
|
|
.map_err(|slash_info| process_slash_info(slash_info, chain))
|
|
}
|
|
|
|
fn apply_to_slasher(self, chain: &BeaconChain<T>) -> Self {
|
|
if let Some(slasher) = chain.slasher.as_ref() {
|
|
slasher.accept_attestation(self.indexed_attestation.clone());
|
|
}
|
|
self
|
|
}
|
|
|
|
/// Verify the attestation, producing extra information about whether it might be slashable.
|
|
fn verify_slashable(
|
|
signed_aggregate: IndexedAggregatedAttestation<'a, T>,
|
|
chain: &BeaconChain<T>,
|
|
check_signature: CheckAttestationSignature,
|
|
) -> Result<Self, AttestationSlashInfo<'a, T, Error>> {
|
|
use AttestationSlashInfo::*;
|
|
|
|
let IndexedAggregatedAttestation {
|
|
signed_aggregate,
|
|
indexed_attestation,
|
|
attestation_root,
|
|
} = signed_aggregate;
|
|
|
|
match check_signature {
|
|
CheckAttestationSignature::Yes => {
|
|
// Ensure that all signatures are valid.
|
|
if let Err(e) = verify_signed_aggregate_signatures(
|
|
chain,
|
|
signed_aggregate,
|
|
&indexed_attestation,
|
|
)
|
|
.and_then(|is_valid| {
|
|
if !is_valid {
|
|
Err(Error::InvalidSignature)
|
|
} else {
|
|
Ok(())
|
|
}
|
|
}) {
|
|
return Err(SignatureInvalid(e));
|
|
}
|
|
}
|
|
CheckAttestationSignature::No => (),
|
|
};
|
|
|
|
if let Err(e) = Self::verify_late_checks(signed_aggregate, attestation_root, chain) {
|
|
return Err(SignatureValid(indexed_attestation, e));
|
|
}
|
|
|
|
Ok(VerifiedAggregatedAttestation {
|
|
signed_aggregate,
|
|
indexed_attestation,
|
|
})
|
|
}
|
|
|
|
/// Returns the underlying `attestation` for the `signed_aggregate`.
|
|
pub fn attestation(&self) -> &Attestation<T::EthSpec> {
|
|
&self.signed_aggregate.message.aggregate
|
|
}
|
|
|
|
/// Returns the underlying `signed_aggregate`.
|
|
pub fn aggregate(&self) -> &SignedAggregateAndProof<T::EthSpec> {
|
|
self.signed_aggregate
|
|
}
|
|
}
|
|
|
|
impl<'a, T: BeaconChainTypes> IndexedUnaggregatedAttestation<'a, T> {
|
|
/// Run the checks that happen before an indexed attestation is constructed.
|
|
pub fn verify_early_checks(
|
|
attestation: &Attestation<T::EthSpec>,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<(), Error> {
|
|
let attestation_epoch = attestation.data.slot.epoch(T::EthSpec::slots_per_epoch());
|
|
|
|
// Check the attestation's epoch matches its target.
|
|
if attestation_epoch != attestation.data.target.epoch {
|
|
return Err(Error::InvalidTargetEpoch {
|
|
slot: attestation.data.slot,
|
|
epoch: attestation.data.target.epoch,
|
|
});
|
|
}
|
|
|
|
// Ensure attestation is within the last ATTESTATION_PROPAGATION_SLOT_RANGE slots (within a
|
|
// MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance).
|
|
//
|
|
// We do not queue future attestations for later processing.
|
|
verify_propagation_slot_range(chain, attestation)?;
|
|
|
|
// Check to ensure that the attestation is "unaggregated". I.e., it has exactly one
|
|
// aggregation bit set.
|
|
let num_aggregation_bits = attestation.aggregation_bits.num_set_bits();
|
|
if num_aggregation_bits != 1 {
|
|
return Err(Error::NotExactlyOneAggregationBitSet(num_aggregation_bits));
|
|
}
|
|
|
|
// Attestations must be for a known block. If the block is unknown, we simply drop the
|
|
// attestation and do not delay consideration for later.
|
|
//
|
|
// Enforce a maximum skip distance for unaggregated attestations.
|
|
let head_block =
|
|
verify_head_block_is_known(chain, attestation, chain.config.import_max_skip_slots)?;
|
|
|
|
// Check the attestation target root is consistent with the head root.
|
|
verify_attestation_target_root::<T::EthSpec>(&head_block, attestation)?;
|
|
|
|
Ok(())
|
|
}
|
|
|
|
/// Run the checks that apply to the indexed attestation before the signature is checked.
|
|
pub fn verify_middle_checks(
|
|
attestation: &Attestation<T::EthSpec>,
|
|
indexed_attestation: &IndexedAttestation<T::EthSpec>,
|
|
committees_per_slot: u64,
|
|
subnet_id: Option<SubnetId>,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<(u64, SubnetId), Error> {
|
|
let expected_subnet_id = SubnetId::compute_subnet_for_attestation_data::<T::EthSpec>(
|
|
&indexed_attestation.data,
|
|
committees_per_slot,
|
|
&chain.spec,
|
|
)
|
|
.map_err(BeaconChainError::from)?;
|
|
|
|
// If a subnet was specified, ensure that subnet is correct.
|
|
if let Some(subnet_id) = subnet_id {
|
|
if subnet_id != expected_subnet_id {
|
|
return Err(Error::InvalidSubnetId {
|
|
received: subnet_id,
|
|
expected: expected_subnet_id,
|
|
});
|
|
}
|
|
};
|
|
|
|
let validator_index = *indexed_attestation
|
|
.attesting_indices
|
|
.first()
|
|
.ok_or(Error::NotExactlyOneAggregationBitSet(0))?;
|
|
|
|
/*
|
|
* The attestation is the first valid attestation received for the participating validator
|
|
* for the slot, attestation.data.slot.
|
|
*/
|
|
if chain
|
|
.observed_gossip_attesters
|
|
.read()
|
|
.validator_has_been_observed(attestation.data.target.epoch, validator_index as usize)
|
|
.map_err(BeaconChainError::from)?
|
|
{
|
|
return Err(Error::PriorAttestationKnown {
|
|
validator_index,
|
|
epoch: attestation.data.target.epoch,
|
|
});
|
|
}
|
|
|
|
Ok((validator_index, expected_subnet_id))
|
|
}
|
|
|
|
/// Returns `Ok(Self)` if the `attestation` is valid to be (re)published on the gossip
|
|
/// network.
|
|
///
|
|
/// `subnet_id` is the subnet from which we received this attestation. This function will
|
|
/// verify that it was received on the correct subnet.
|
|
pub fn verify(
|
|
attestation: &'a Attestation<T::EthSpec>,
|
|
subnet_id: Option<SubnetId>,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<Self, Error> {
|
|
Self::verify_slashable(attestation, subnet_id, chain)
|
|
.map(|verified_unaggregated| {
|
|
if let Some(slasher) = chain.slasher.as_ref() {
|
|
slasher.accept_attestation(verified_unaggregated.indexed_attestation.clone());
|
|
}
|
|
verified_unaggregated
|
|
})
|
|
.map_err(|slash_info| process_slash_info(slash_info, chain))
|
|
}
|
|
|
|
/// Verify the attestation, producing extra information about whether it might be slashable.
|
|
pub fn verify_slashable(
|
|
attestation: &'a Attestation<T::EthSpec>,
|
|
subnet_id: Option<SubnetId>,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<Self, AttestationSlashInfo<'a, T, Error>> {
|
|
use AttestationSlashInfo::*;
|
|
|
|
if let Err(e) = Self::verify_early_checks(attestation, chain) {
|
|
return Err(SignatureNotChecked(attestation, e));
|
|
}
|
|
|
|
let (indexed_attestation, committees_per_slot) =
|
|
match obtain_indexed_attestation_and_committees_per_slot(chain, attestation) {
|
|
Ok(x) => x,
|
|
Err(e) => {
|
|
return Err(SignatureNotChecked(attestation, e));
|
|
}
|
|
};
|
|
|
|
let (validator_index, expected_subnet_id) = match Self::verify_middle_checks(
|
|
attestation,
|
|
&indexed_attestation,
|
|
committees_per_slot,
|
|
subnet_id,
|
|
chain,
|
|
) {
|
|
Ok(t) => t,
|
|
Err(e) => return Err(SignatureNotCheckedIndexed(indexed_attestation, e)),
|
|
};
|
|
|
|
Ok(Self {
|
|
attestation,
|
|
indexed_attestation,
|
|
subnet_id: expected_subnet_id,
|
|
validator_index,
|
|
})
|
|
}
|
|
|
|
/// Returns a mutable reference to the underlying attestation.
|
|
///
|
|
/// Only use during testing since modifying the `IndexedAttestation` can cause the attestation
|
|
/// to no-longer be valid.
|
|
pub fn __indexed_attestation_mut(&mut self) -> &mut IndexedAttestation<T::EthSpec> {
|
|
&mut self.indexed_attestation
|
|
}
|
|
}
|
|
|
|
impl<'a, T: BeaconChainTypes> VerifiedUnaggregatedAttestation<'a, T> {
|
|
/// Run the checks that apply after the signature has been checked.
|
|
fn verify_late_checks(
|
|
attestation: &Attestation<T::EthSpec>,
|
|
validator_index: u64,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<(), Error> {
|
|
// Now that the attestation has been fully verified, store that we have received a valid
|
|
// attestation from this validator.
|
|
//
|
|
// It's important to double check that the attestation still hasn't been observed, since
|
|
// there can be a race-condition if we receive two attestations at the same time and
|
|
// process them in different threads.
|
|
if chain
|
|
.observed_gossip_attesters
|
|
.write()
|
|
.observe_validator(attestation.data.target.epoch, validator_index as usize)
|
|
.map_err(BeaconChainError::from)?
|
|
{
|
|
return Err(Error::PriorAttestationKnown {
|
|
validator_index,
|
|
epoch: attestation.data.target.epoch,
|
|
});
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
/// Verify the `unaggregated_attestation`.
|
|
pub fn verify(
|
|
unaggregated_attestation: &'a Attestation<T::EthSpec>,
|
|
subnet_id: Option<SubnetId>,
|
|
chain: &BeaconChain<T>,
|
|
) -> Result<Self, Error> {
|
|
let indexed =
|
|
IndexedUnaggregatedAttestation::verify(unaggregated_attestation, subnet_id, chain)?;
|
|
Self::from_indexed(indexed, chain, CheckAttestationSignature::Yes)
|
|
}
|
|
|
|
/// Complete the verification of an indexed attestation.
|
|
fn from_indexed(
|
|
attestation: IndexedUnaggregatedAttestation<'a, T>,
|
|
chain: &BeaconChain<T>,
|
|
check_signature: CheckAttestationSignature,
|
|
) -> Result<Self, Error> {
|
|
Self::verify_slashable(attestation, chain, check_signature)
|
|
.map(|verified_unaggregated| verified_unaggregated.apply_to_slasher(chain))
|
|
.map_err(|slash_info| process_slash_info(slash_info, chain))
|
|
}
|
|
|
|
fn apply_to_slasher(self, chain: &BeaconChain<T>) -> Self {
|
|
if let Some(slasher) = chain.slasher.as_ref() {
|
|
slasher.accept_attestation(self.indexed_attestation.clone());
|
|
}
|
|
self
|
|
}
|
|
|
|
/// Verify the attestation, producing extra information about whether it might be slashable.
|
|
fn verify_slashable(
|
|
attestation: IndexedUnaggregatedAttestation<'a, T>,
|
|
chain: &BeaconChain<T>,
|
|
check_signature: CheckAttestationSignature,
|
|
) -> Result<Self, AttestationSlashInfo<'a, T, Error>> {
|
|
use AttestationSlashInfo::*;
|
|
|
|
let IndexedUnaggregatedAttestation {
|
|
attestation,
|
|
indexed_attestation,
|
|
subnet_id,
|
|
validator_index,
|
|
} = attestation;
|
|
|
|
match check_signature {
|
|
CheckAttestationSignature::Yes => {
|
|
if let Err(e) = verify_attestation_signature(chain, &indexed_attestation) {
|
|
return Err(SignatureInvalid(e));
|
|
}
|
|
}
|
|
CheckAttestationSignature::No => (),
|
|
};
|
|
|
|
if let Err(e) = Self::verify_late_checks(attestation, validator_index, chain) {
|
|
return Err(SignatureValid(indexed_attestation, e));
|
|
}
|
|
|
|
Ok(Self {
|
|
attestation,
|
|
indexed_attestation,
|
|
subnet_id,
|
|
})
|
|
}
|
|
|
|
/// Returns the correct subnet for the attestation.
|
|
pub fn subnet_id(&self) -> SubnetId {
|
|
self.subnet_id
|
|
}
|
|
|
|
/// Returns the wrapped `attestation`.
|
|
pub fn attestation(&self) -> &Attestation<T::EthSpec> {
|
|
self.attestation
|
|
}
|
|
|
|
/// Returns the wrapped `indexed_attestation`.
|
|
pub fn indexed_attestation(&self) -> &IndexedAttestation<T::EthSpec> {
|
|
&self.indexed_attestation
|
|
}
|
|
|
|
/// Returns a mutable reference to the underlying attestation.
|
|
///
|
|
/// Only use during testing since modifying the `IndexedAttestation` can cause the attestation
|
|
/// to no-longer be valid.
|
|
pub fn __indexed_attestation_mut(&mut self) -> &mut IndexedAttestation<T::EthSpec> {
|
|
&mut self.indexed_attestation
|
|
}
|
|
}
|
|
|
|
/// Returns `Ok(())` if the `attestation.data.beacon_block_root` is known to this chain.
|
|
/// You can use this `shuffling_id` to read from the shuffling cache.
|
|
///
|
|
/// The block root may not be known for two reasons:
|
|
///
|
|
/// 1. The block has never been verified by our application.
|
|
/// 2. The block is prior to the latest finalized block.
|
|
///
|
|
/// Case (1) is the exact thing we're trying to detect. However case (2) is a little different, but
|
|
/// it's still fine to reject here because there's no need for us to handle attestations that are
|
|
/// already finalized.
|
|
fn verify_head_block_is_known<T: BeaconChainTypes>(
|
|
chain: &BeaconChain<T>,
|
|
attestation: &Attestation<T::EthSpec>,
|
|
max_skip_slots: Option<u64>,
|
|
) -> Result<ProtoBlock, Error> {
|
|
if let Some(block) = chain
|
|
.fork_choice
|
|
.read()
|
|
.get_block(&attestation.data.beacon_block_root)
|
|
{
|
|
// Reject any block that exceeds our limit on skipped slots.
|
|
if let Some(max_skip_slots) = max_skip_slots {
|
|
if attestation.data.slot > block.slot + max_skip_slots {
|
|
return Err(Error::TooManySkippedSlots {
|
|
head_block_slot: block.slot,
|
|
attestation_slot: attestation.data.slot,
|
|
});
|
|
}
|
|
}
|
|
|
|
Ok(block)
|
|
} else {
|
|
Err(Error::UnknownHeadBlock {
|
|
beacon_block_root: attestation.data.beacon_block_root,
|
|
})
|
|
}
|
|
}
|
|
|
|
/// Verify that the `attestation` is within the acceptable gossip propagation range, with reference
|
|
/// to the current slot of the `chain`.
|
|
///
|
|
/// Accounts for `MAXIMUM_GOSSIP_CLOCK_DISPARITY`.
|
|
pub fn verify_propagation_slot_range<T: BeaconChainTypes>(
|
|
chain: &BeaconChain<T>,
|
|
attestation: &Attestation<T::EthSpec>,
|
|
) -> Result<(), Error> {
|
|
let attestation_slot = attestation.data.slot;
|
|
|
|
let latest_permissible_slot = chain
|
|
.slot_clock
|
|
.now_with_future_tolerance(MAXIMUM_GOSSIP_CLOCK_DISPARITY)
|
|
.ok_or(BeaconChainError::UnableToReadSlot)?;
|
|
if attestation_slot > latest_permissible_slot {
|
|
return Err(Error::FutureSlot {
|
|
attestation_slot,
|
|
latest_permissible_slot,
|
|
});
|
|
}
|
|
|
|
// Taking advantage of saturating subtraction on `Slot`.
|
|
let earliest_permissible_slot = chain
|
|
.slot_clock
|
|
.now_with_past_tolerance(MAXIMUM_GOSSIP_CLOCK_DISPARITY)
|
|
.ok_or(BeaconChainError::UnableToReadSlot)?
|
|
- T::EthSpec::slots_per_epoch();
|
|
if attestation_slot < earliest_permissible_slot {
|
|
return Err(Error::PastSlot {
|
|
attestation_slot,
|
|
earliest_permissible_slot,
|
|
});
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
/// Verifies that the signature of the `indexed_attestation` is valid.
|
|
pub fn verify_attestation_signature<T: BeaconChainTypes>(
|
|
chain: &BeaconChain<T>,
|
|
indexed_attestation: &IndexedAttestation<T::EthSpec>,
|
|
) -> Result<(), Error> {
|
|
let signature_setup_timer =
|
|
metrics::start_timer(&metrics::ATTESTATION_PROCESSING_SIGNATURE_SETUP_TIMES);
|
|
|
|
let pubkey_cache = chain
|
|
.validator_pubkey_cache
|
|
.try_read_for(VALIDATOR_PUBKEY_CACHE_LOCK_TIMEOUT)
|
|
.ok_or(BeaconChainError::ValidatorPubkeyCacheLockTimeout)?;
|
|
|
|
let fork = chain
|
|
.spec
|
|
.fork_at_epoch(indexed_attestation.data.target.epoch);
|
|
|
|
let signature_set = indexed_attestation_signature_set_from_pubkeys(
|
|
|validator_index| pubkey_cache.get(validator_index).map(Cow::Borrowed),
|
|
&indexed_attestation.signature,
|
|
indexed_attestation,
|
|
&fork,
|
|
chain.genesis_validators_root,
|
|
&chain.spec,
|
|
)
|
|
.map_err(BeaconChainError::SignatureSetError)?;
|
|
|
|
metrics::stop_timer(signature_setup_timer);
|
|
|
|
let _signature_verification_timer =
|
|
metrics::start_timer(&metrics::ATTESTATION_PROCESSING_SIGNATURE_TIMES);
|
|
|
|
if signature_set.verify() {
|
|
Ok(())
|
|
} else {
|
|
Err(Error::InvalidSignature)
|
|
}
|
|
}
|
|
|
|
/// Verifies that the `attestation.data.target.root` is indeed the target root of the block at
|
|
/// `attestation.data.beacon_block_root`.
|
|
pub fn verify_attestation_target_root<T: EthSpec>(
|
|
head_block: &ProtoBlock,
|
|
attestation: &Attestation<T>,
|
|
) -> Result<(), Error> {
|
|
// Check the attestation target root.
|
|
let head_block_epoch = head_block.slot.epoch(T::slots_per_epoch());
|
|
let attestation_epoch = attestation.data.slot.epoch(T::slots_per_epoch());
|
|
if head_block_epoch > attestation_epoch {
|
|
// The epoch references an invalid head block from a future epoch.
|
|
//
|
|
// This check is not in the specification, however we guard against it since it opens us up
|
|
// to weird edge cases during verification.
|
|
//
|
|
// Whilst this attestation *technically* could be used to add value to a block, it is
|
|
// invalid in the spirit of the protocol. Here we choose safety over profit.
|
|
//
|
|
// Reference:
|
|
// https://github.com/ethereum/eth2.0-specs/pull/2001#issuecomment-699246659
|
|
return Err(Error::InvalidTargetRoot {
|
|
attestation: attestation.data.target.root,
|
|
// It is not clear what root we should expect in this case, since the attestation is
|
|
// fundamentally invalid.
|
|
expected: None,
|
|
});
|
|
} else {
|
|
let target_root = if head_block_epoch == attestation_epoch {
|
|
// If the block is in the same epoch as the attestation, then use the target root
|
|
// from the block.
|
|
head_block.target_root
|
|
} else {
|
|
// If the head block is from a previous epoch then skip slots will cause the head block
|
|
// root to become the target block root.
|
|
//
|
|
// We know the head block is from a previous epoch due to a previous check.
|
|
head_block.root
|
|
};
|
|
|
|
// Reject any attestation with an invalid target root.
|
|
if target_root != attestation.data.target.root {
|
|
return Err(Error::InvalidTargetRoot {
|
|
attestation: attestation.data.target.root,
|
|
expected: Some(target_root),
|
|
});
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
/// Verifies all the signatures in a `SignedAggregateAndProof` using BLS batch verification. This
|
|
/// includes three signatures:
|
|
///
|
|
/// - `signed_aggregate.signature`
|
|
/// - `signed_aggregate.message.selection_proof`
|
|
/// - `signed_aggregate.message.aggregate.signature`
|
|
///
|
|
/// # Returns
|
|
///
|
|
/// - `Ok(true)`: if all signatures are valid.
|
|
/// - `Ok(false)`: if one or more signatures are invalid.
|
|
/// - `Err(e)`: if there was an error preventing signature verification.
|
|
pub fn verify_signed_aggregate_signatures<T: BeaconChainTypes>(
|
|
chain: &BeaconChain<T>,
|
|
signed_aggregate: &SignedAggregateAndProof<T::EthSpec>,
|
|
indexed_attestation: &IndexedAttestation<T::EthSpec>,
|
|
) -> Result<bool, Error> {
|
|
let pubkey_cache = chain
|
|
.validator_pubkey_cache
|
|
.try_read_for(VALIDATOR_PUBKEY_CACHE_LOCK_TIMEOUT)
|
|
.ok_or(BeaconChainError::ValidatorPubkeyCacheLockTimeout)?;
|
|
|
|
let aggregator_index = signed_aggregate.message.aggregator_index;
|
|
if aggregator_index >= pubkey_cache.len() as u64 {
|
|
return Err(Error::AggregatorPubkeyUnknown(aggregator_index));
|
|
}
|
|
|
|
let fork = chain
|
|
.spec
|
|
.fork_at_epoch(indexed_attestation.data.target.epoch);
|
|
|
|
let signature_sets = vec![
|
|
signed_aggregate_selection_proof_signature_set(
|
|
|validator_index| pubkey_cache.get(validator_index).map(Cow::Borrowed),
|
|
signed_aggregate,
|
|
&fork,
|
|
chain.genesis_validators_root,
|
|
&chain.spec,
|
|
)
|
|
.map_err(BeaconChainError::SignatureSetError)?,
|
|
signed_aggregate_signature_set(
|
|
|validator_index| pubkey_cache.get(validator_index).map(Cow::Borrowed),
|
|
signed_aggregate,
|
|
&fork,
|
|
chain.genesis_validators_root,
|
|
&chain.spec,
|
|
)
|
|
.map_err(BeaconChainError::SignatureSetError)?,
|
|
indexed_attestation_signature_set_from_pubkeys(
|
|
|validator_index| pubkey_cache.get(validator_index).map(Cow::Borrowed),
|
|
&indexed_attestation.signature,
|
|
indexed_attestation,
|
|
&fork,
|
|
chain.genesis_validators_root,
|
|
&chain.spec,
|
|
)
|
|
.map_err(BeaconChainError::SignatureSetError)?,
|
|
];
|
|
|
|
Ok(verify_signature_sets(signature_sets.iter()))
|
|
}
|
|
|
|
/// Assists in readability.
|
|
type CommitteesPerSlot = u64;
|
|
|
|
/// Returns the `indexed_attestation` and committee count per slot for the `attestation` using the
|
|
/// public keys cached in the `chain`.
|
|
pub fn obtain_indexed_attestation_and_committees_per_slot<T: BeaconChainTypes>(
|
|
chain: &BeaconChain<T>,
|
|
attestation: &Attestation<T::EthSpec>,
|
|
) -> Result<(IndexedAttestation<T::EthSpec>, CommitteesPerSlot), Error> {
|
|
map_attestation_committee(chain, attestation, |(committee, committees_per_slot)| {
|
|
get_indexed_attestation(committee.committee, attestation)
|
|
.map(|attestation| (attestation, committees_per_slot))
|
|
.map_err(Error::Invalid)
|
|
})
|
|
}
|
|
|
|
/// Runs the `map_fn` with the committee and committee count per slot for the given `attestation`.
|
|
///
|
|
/// This function exists in this odd "map" pattern because efficiently obtaining the committee for
|
|
/// an attestation can be complex. It might involve reading straight from the
|
|
/// `beacon_chain.shuffling_cache` or it might involve reading it from a state from the DB. Due to
|
|
/// the complexities of `RwLock`s on the shuffling cache, a simple `Cow` isn't suitable here.
|
|
///
|
|
/// If the committee for `attestation` isn't found in the `shuffling_cache`, we will read a state
|
|
/// from disk and then update the `shuffling_cache`.
|
|
fn map_attestation_committee<T, F, R>(
|
|
chain: &BeaconChain<T>,
|
|
attestation: &Attestation<T::EthSpec>,
|
|
map_fn: F,
|
|
) -> Result<R, Error>
|
|
where
|
|
T: BeaconChainTypes,
|
|
F: Fn((BeaconCommittee, CommitteesPerSlot)) -> Result<R, Error>,
|
|
{
|
|
let attestation_epoch = attestation.data.slot.epoch(T::EthSpec::slots_per_epoch());
|
|
let target = &attestation.data.target;
|
|
|
|
// Attestation target must be for a known block.
|
|
//
|
|
// We use fork choice to find the target root, which means that we reject any attestation
|
|
// that has a `target.root` earlier than our latest finalized root. There's no point in
|
|
// processing an attestation that does not include our latest finalized block in its chain.
|
|
//
|
|
// We do not delay consideration for later, we simply drop the attestation.
|
|
if !chain.fork_choice.read().contains_block(&target.root) {
|
|
return Err(Error::UnknownTargetRoot(target.root));
|
|
}
|
|
|
|
chain
|
|
.with_committee_cache(target.root, attestation_epoch, |committee_cache, _| {
|
|
let committees_per_slot = committee_cache.committees_per_slot();
|
|
|
|
Ok(committee_cache
|
|
.get_beacon_committee(attestation.data.slot, attestation.data.index)
|
|
.map(|committee| map_fn((committee, committees_per_slot)))
|
|
.unwrap_or_else(|| {
|
|
Err(Error::NoCommitteeForSlotAndIndex {
|
|
slot: attestation.data.slot,
|
|
index: attestation.data.index,
|
|
})
|
|
}))
|
|
})
|
|
.map_err(BeaconChainError::from)?
|
|
}
|