# beacon_chain # Copyright (c) 2019-2024 Status Research & Development GmbH # Licensed and distributed under either of # * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT). # * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0). # at your option. This file may not be copied, modified, or distributed except according to those terms. {.push raises: [].} import # Status chronicles, chronos, metrics, results, # Internals ../spec/[ beaconstate, state_transition_block, forks, helpers, network, signatures], ../consensus_object_pools/[ attestation_pool, blockchain_dag, blob_quarantine, block_quarantine, spec_cache, light_client_pool, sync_committee_msg_pool, validator_change_pool], ".."/[beacon_clock], ./batch_validation from libp2p/protocols/pubsub/errors import ValidationResult export results, ValidationResult logScope: topics = "gossip_checks" declareCounter beacon_attestations_dropped_queue_full, "Number of attestations dropped because queue is full" declareCounter beacon_aggregates_dropped_queue_full, "Number of aggregates dropped because queue is full" declareCounter beacon_sync_messages_dropped_queue_full, "Number of sync committee messages dropped because queue is full" declareCounter beacon_contributions_dropped_queue_full, "Number of sync committee contributions dropped because queue is full" # This result is a little messy in that it returns Result.ok for # ValidationResult.Accept and an err for the others - this helps transport # an error message to callers but could arguably be done in an cleaner way. type ValidationError* = (ValidationResult, cstring) template errIgnore*(msg: cstring): untyped = err((ValidationResult.Ignore, cstring msg)) template errReject*(msg: cstring): untyped = err((ValidationResult.Reject, cstring msg)) # Internal checks # ---------------------------------------------------------------- func check_attestation_block( pool: AttestationPool, attestationSlot: Slot, blck: BlockRef): Result[void, ValidationError] = # The voted-for block must be a descendant of the finalized block, thus it # must at least as new than the finalized checkpoint - in theory it could be # equal, but then we're voting for an already-finalized block which is pretty # useless - other blocks that are not rooted in the finalized chain will be # pruned by the chain dag, and thus we can no longer get a BlockRef for them if not (blck.slot > pool.dag.finalizedHead.slot): return errIgnore("Voting for already-finalized block") # The attestation shouldn't be voting for a block that didn't exist at the # time - not in spec, but hard to reason about if not (attestationSlot >= blck.slot): return errIgnore("Voting for block that didn't exist at the time") # We'll also cap it at 4 epochs which is somewhat arbitrary, but puts an # upper bound on the processing done to validate the attestation # TODO revisit with less arbitrary approach if not ((attestationSlot - blck.slot) <= uint64(4 * SLOTS_PER_EPOCH)): return errIgnore("Voting for very old block") ok() func check_propagation_slot_range( consensusFork: ConsensusFork, msgSlot: Slot, wallTime: BeaconTime): Result[Slot, ValidationError] = let futureSlot = (wallTime + MAXIMUM_GOSSIP_CLOCK_DISPARITY).toSlot() if not futureSlot.afterGenesis or msgSlot > futureSlot.slot: return errIgnore("Attestation slot in the future") let pastSlot = (wallTime - MAXIMUM_GOSSIP_CLOCK_DISPARITY).toSlot() if not pastSlot.afterGenesis: return ok(msgSlot) if consensusFork < ConsensusFork.Deneb: # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/phase0/p2p-interface.md#configuration # The spec value of ATTESTATION_PROPAGATION_SLOT_RANGE is 32, but it can # retransmit attestations on the cusp of being out of spec, and which by # the time they reach their destination might be out of spec. const TIME_IN_FLIGHT_BUFFER = 4 static: doAssert ATTESTATION_PROPAGATION_SLOT_RANGE > TIME_IN_FLIGHT_BUFFER if msgSlot + (ATTESTATION_PROPAGATION_SLOT_RANGE - TIME_IN_FLIGHT_BUFFER) < pastSlot.slot: return errIgnore("Attestation slot in the past") else: # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.2/specs/deneb/p2p-interface.md#beacon_attestation_subnet_id # "[IGNORE] the epoch of attestation.data.slot is either the current or # previous epoch (with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance) -- i.e. # compute_epoch_at_slot(attestation.data.slot) in # (get_previous_epoch(state), get_current_epoch(state))" # # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.2/specs/deneb/p2p-interface.md#beacon_aggregate_and_proof # "[IGNORE] the epoch of aggregate.data.slot is either the current or # previous epoch (with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance) -- i.e. # compute_epoch_at_slot(aggregate.data.slot) in # (get_previous_epoch(state), get_current_epoch(state))" if msgSlot.epoch < pastSlot.slot.epoch.get_previous_epoch: return errIgnore("Attestation slot in the past") ok(msgSlot) func check_slot_exact(msgSlot: Slot, wallTime: BeaconTime): Result[Slot, ValidationError] = let futureSlot = (wallTime + MAXIMUM_GOSSIP_CLOCK_DISPARITY).toSlot() if not futureSlot.afterGenesis or msgSlot > futureSlot.slot: return errIgnore("Sync committee slot in the future") let pastSlot = (wallTime - MAXIMUM_GOSSIP_CLOCK_DISPARITY).toSlot() if pastSlot.afterGenesis and msgSlot < pastSlot.slot: return errIgnore("Sync committee slot in the past") ok(msgSlot) func check_beacon_and_target_block( pool: var AttestationPool, data: AttestationData): Result[BlockSlot, ValidationError] = # The block being voted for (data.beacon_block_root) passes validation - by # extension, the target block must at that point also pass validation. # The target block is returned. # We rely on the chain DAG to have been validated, so check for the existence # of the block in the pool. let blck = pool.dag.getBlockRef(data.beacon_block_root).valueOr: pool.quarantine[].addMissing(data.beacon_block_root) return errIgnore("Attestation block unknown") # Not in spec - check that rewinding to the state is sane ? check_attestation_block(pool, data.slot, blck) # [REJECT] The attestation's target block is an ancestor of the block named # in the LMD vote -- i.e. # get_checkpoint_block(store, attestation.data.beacon_block_root, # attestation.data.target.epoch) == attestation.data.target.root # the sanity of target.epoch has been checked by check_attestation_slot_target let target = blck.atCheckpoint(data.target).valueOr: return errReject("Attestation target is not ancestor of LMD vote block") ok(target) func check_aggregation_count( attestation: Attestation, singular: bool): Result[void, ValidationError] = let ones = attestation.aggregation_bits.countOnes() if singular and ones != 1: return errReject("Attestation must have a single attestation bit set") elif not singular and ones < 1: return errReject("Attestation must have at least one attestation bit set") ok() func check_attestation_subnet( shufflingRef: ShufflingRef, slot: Slot, committee_index: CommitteeIndex, subnet_id: SubnetId): Result[void, ValidationError] = let expectedSubnet = compute_subnet_for_attestation( get_committee_count_per_slot(shufflingRef), slot, committee_index) if expectedSubnet != subnet_id: return errReject("Attestation not on the correct subnet") ok() func check_blob_sidecar_inclusion_proof( blob_sidecar: deneb.BlobSidecar): Result[void, ValidationError] = let res = blob_sidecar.verify_blob_sidecar_inclusion_proof() if res.isErr: return errReject(res.error) ok() # Gossip Validation # ---------------------------------------------------------------- # Generally, the following rules apply for gossip validation: # # [REJECT] # This doesn't depend on the wall clock or the exact state of the DAG; it's # an internal consistency/correctness check only, and effectively never has # false positives. These don't, for example, arise from timeouts. # # [IGNORE] # This may be intermittent, depend on timing or the current state of the DAG. template checkedReject( msg: cstring, strictVerification: bool): untyped = if strictVerification: raiseAssert $msg errReject(msg) template checkedReject( error: ValidationError, strictVerification: bool): untyped = doAssert error[0] == ValidationResult.Reject if strictVerification: raiseAssert $error[1] err(error) template checkedResult*( error: ValidationError, strictVerification: bool): untyped = if error[0] == ValidationResult.Reject and strictVerification: raiseAssert $error[1] err(error) # ChainDAGRef template checkedReject( dag: ChainDAGRef, msg: cstring): untyped = checkedReject(msg, strictVerification in dag.updateFlags) template checkedReject( dag: ChainDAGRef, error: ValidationError): untyped = checkedReject(error, strictVerification in dag.updateFlags) template checkedResult( dag: ChainDAGRef, error: ValidationError): untyped = checkedResult(error, strictVerification in dag.updateFlags) # AttestationPool template checkedReject( pool: ref AttestationPool, msg: cstring): untyped = pool[].dag.checkedReject(msg) template checkedReject( pool: ref AttestationPool, error: ValidationError): untyped = pool[].dag.checkedReject(error) template checkedResult( pool: ref AttestationPool, error: ValidationError): untyped = pool[].dag.checkedResult(error) # ValidatorChangePool template checkedReject( pool: ValidatorChangePool, msg: cstring): untyped = pool.dag.checkedReject(msg) template checkedReject( pool: ValidatorChangePool, error: ValidationError): untyped = pool.dag.checkedReject(error) template checkedResult( pool: ValidatorChangePool, error: ValidationError): untyped = pool.dag.checkedResult(error) template validateBeaconBlockBellatrix( signed_beacon_block: phase0.SignedBeaconBlock | altair.SignedBeaconBlock, parent: BlockRef): untyped = discard # https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/bellatrix/p2p-interface.md#beacon_block template validateBeaconBlockBellatrix( signed_beacon_block: bellatrix.SignedBeaconBlock | capella.SignedBeaconBlock | deneb.SignedBeaconBlock | electra.SignedBeaconBlock, parent: BlockRef): untyped = # If the execution is enabled for the block -- i.e. # is_execution_enabled(state, block.body) then validate the following: # # `is_execution_enabled(state, block.body)` is # `is_merge_transition_block(state, block.body) or is_merge_transition_complete(state)` is # `(not is_merge_transition_complete(state) and block.body.execution_payload != ExecutionPayload()) or is_merge_transition_complete(state)` is # `is_merge_transition_complete(state) or block.body.execution_payload != ExecutionPayload()` is # `is_merge_transition_complete(state) or is_execution_block(block)` # # `is_merge_transition_complete(state)` tests for # `state.latest_execution_payload_header != ExecutionPayloadHeader()`, while # https://github.com/ethereum/consensus-specs/blob/v1.4.0/specs/bellatrix/beacon-chain.md#block-processing # shows that `state.latest_execution_payload_header` being default or not is # exactly equivalent to whether that block's execution payload is default or # not, so test cached block information rather than reconstructing a state. let isExecutionEnabled = if signed_beacon_block.message.is_execution_block: true else: # If we don't know whether the parent block had execution enabled, # assume it didn't. This way, we don't reject here if the timestamp # is invalid, and let state transition check the timestamp. # This is an edge case, and may be hit in a pathological scenario with # checkpoint sync, because the checkpoint block may be unavailable # and it could already be the parent of the new block before backfill. not dag.loadExecutionBlockHash(parent).get(ZERO_HASH).isZero if isExecutionEnabled: # [REJECT] The block's execution payload timestamp is correct with respect # to the slot -- i.e. execution_payload.timestamp == # compute_timestamp_at_slot(state, block.slot). let timestampAtSlot = withState(dag.headState): compute_timestamp_at_slot( forkyState.data, signed_beacon_block.message.slot) if not (signed_beacon_block.message.body.execution_payload.timestamp == timestampAtSlot): quarantine[].addUnviable(signed_beacon_block.root) return dag.checkedReject( "BeaconBlock: mismatched execution payload timestamp") # The condition: # [REJECT] The block's parent (defined by `block.parent_root`) passes all # validation (excluding execution node verification of the # `block.body.execution_payload`). # cannot occur here, because Nimbus's optimistic sync waits for either # `ACCEPTED` or `SYNCING` from the EL to get this far. # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.4/specs/deneb/p2p-interface.md#blob_sidecar_subnet_id proc validateBlobSidecar*( dag: ChainDAGRef, quarantine: ref Quarantine, blobQuarantine: ref BlobQuarantine, blob_sidecar: BlobSidecar, wallTime: BeaconTime, subnet_id: BlobId): Result[void, ValidationError] = # Some of the checks below have been reordered compared to the spec, to # perform the cheap checks first - in particular, we want to avoid loading # an `EpochRef` and checking signatures. This reordering might lead to # different IGNORE/REJECT results in turn affecting gossip scores. template block_header: untyped = blob_sidecar.signed_block_header.message # [REJECT] The sidecar's index is consistent with `MAX_BLOBS_PER_BLOCK` # -- i.e. `blob_sidecar.index < MAX_BLOBS_PER_BLOCK` if not (blob_sidecar.index < MAX_BLOBS_PER_BLOCK): return dag.checkedReject("BlobSidecar: index inconsistent") # [REJECT] The sidecar is for the correct subnet -- i.e. # `compute_subnet_for_blob_sidecar(blob_sidecar.index) == subnet_id`. if not (compute_subnet_for_blob_sidecar(blob_sidecar.index) == subnet_id): return dag.checkedReject("BlobSidecar: subnet incorrect") # [IGNORE] The sidecar is not from a future slot (with a # `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) -- i.e. validate that # `block_header.slot <= current_slot` (a client MAY queue future sidecars # for processing at the appropriate slot). if not (block_header.slot <= (wallTime + MAXIMUM_GOSSIP_CLOCK_DISPARITY).slotOrZero): return errIgnore("BlobSidecar: slot too high") # [IGNORE] The sidecar is from a slot greater than the latest # finalized slot -- i.e. validate that `block_header.slot > # compute_start_slot_at_epoch(state.finalized_checkpoint.epoch)` if not (block_header.slot > dag.finalizedHead.slot): return errIgnore("BlobSidecar: slot already finalized") # [IGNORE] The sidecar is the first sidecar for the tuple # (block_header.slot, block_header.proposer_index, blob_sidecar.index) # with valid header signature, sidecar inclusion proof, and kzg proof. let block_root = hash_tree_root(block_header) if dag.getBlockRef(block_root).isSome(): return errIgnore("BlobSidecar: already have block") if blobQuarantine[].hasBlob( block_header.slot, block_header.proposer_index, blob_sidecar.index): return errIgnore("BlobSidecar: already have valid blob from same proposer") # [REJECT] The sidecar's inclusion proof is valid as verified by # `verify_blob_sidecar_inclusion_proof(blob_sidecar)`. block: let v = check_blob_sidecar_inclusion_proof(blob_sidecar) if v.isErr: return dag.checkedReject(v.error) # [IGNORE] The sidecar's block's parent (defined by # `block_header.parent_root`) has been seen (via both gossip and # non-gossip sources) (a client MAY queue sidecars for processing # once the parent block is retrieved). # # [REJECT] The sidecar's block's parent (defined by # `block_header.parent_root`) passes validation. let parent = dag.getBlockRef(block_header.parent_root).valueOr: if block_header.parent_root in quarantine[].unviable: quarantine[].addUnviable(block_root) return dag.checkedReject("BlobSidecar: parent not validated") else: quarantine[].addMissing(block_header.parent_root) return errIgnore("BlobSidecar: parent not found") # [REJECT] The sidecar is from a higher slot than the sidecar's # block's parent (defined by `block_header.parent_root`). if not (block_header.slot > parent.bid.slot): return dag.checkedReject("BlobSidecar: slot lower than parents'") # [REJECT] The current finalized_checkpoint is an ancestor of the sidecar's # block -- i.e. `get_checkpoint_block(store, block_header.parent_root, # store.finalized_checkpoint.epoch) == store.finalized_checkpoint.root`. let finalized_checkpoint = getStateField(dag.headState, finalized_checkpoint) ancestor = get_ancestor(parent, finalized_checkpoint.epoch.start_slot) if ancestor.isNil: # This shouldn't happen: we should always be able to trace the parent back # to the finalized checkpoint (else it wouldn't be in the DAG) return errIgnore("BlobSidecar: Can't find ancestor") if not ( finalized_checkpoint.root == ancestor.root or finalized_checkpoint.root.isZero): quarantine[].addUnviable(block_root) return dag.checkedReject( "BlobSidecar: Finalized checkpoint not an ancestor") # [REJECT] The sidecar is proposed by the expected `proposer_index` # for the block's slot in the context of the current shuffling # (defined by `block_header.parent_root`/`block_header.slot`). # If the proposer_index cannot immediately be verified against the expected # shuffling, the sidecar MAY be queued for later processing while proposers # for the block's branch are calculated -- in such a case do not # REJECT, instead IGNORE this message. let proposer = getProposer(dag, parent, block_header.slot).valueOr: warn "cannot compute proposer for blob" return errIgnore("BlobSidecar: Cannot compute proposer") # internal issue if uint64(proposer) != block_header.proposer_index: return dag.checkedReject("BlobSidecar: Unexpected proposer") # [REJECT] The proposer signature of `blob_sidecar.signed_block_header`, # is valid with respect to the `block_header.proposer_index` pubkey. if not verify_block_signature( dag.forkAtEpoch(block_header.slot.epoch), getStateField(dag.headState, genesis_validators_root), block_header.slot, block_root, dag.validatorKey(proposer).get(), blob_sidecar.signed_block_header.signature): return dag.checkedReject("BlobSidecar: Invalid proposer signature") # [REJECT] The sidecar's blob is valid as verified by `verify_blob_kzg_proof( # blob_sidecar.blob, blob_sidecar.kzg_commitment, blob_sidecar.kzg_proof)`. block: let ok = verifyProof( blob_sidecar.blob, blob_sidecar.kzg_commitment, blob_sidecar.kzg_proof).valueOr: return dag.checkedReject("BlobSidecar: blob verify failed") if not ok: return dag.checkedReject("BlobSidecar: blob invalid") # Send notification about new blob sidecar via callback if not(isNil(blobQuarantine.onBlobSidecarCallback)): blobQuarantine.onBlobSidecarCallback(blob_sidecar) ok() # https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/phase0/p2p-interface.md#beacon_block # https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/bellatrix/p2p-interface.md#beacon_block proc validateBeaconBlock*( dag: ChainDAGRef, quarantine: ref Quarantine, signed_beacon_block: ForkySignedBeaconBlock, wallTime: BeaconTime, flags: UpdateFlags): Result[void, ValidationError] = # In general, checks are ordered from cheap to expensive. Especially, crypto # verification could be quite a bit more expensive than the rest. This is an # externally easy-to-invoke function by tossing network packets at the node. # [IGNORE] The block is not from a future slot (with a # MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance) -- i.e. validate that # signed_beacon_block.message.slot <= current_slot (a client MAY queue future # blocks for processing at the appropriate slot). if not (signed_beacon_block.message.slot <= (wallTime + MAXIMUM_GOSSIP_CLOCK_DISPARITY).slotOrZero): return errIgnore("BeaconBlock: slot too high") # [IGNORE] The block is from a slot greater than the latest finalized slot -- # i.e. validate that signed_beacon_block.message.slot > # compute_start_slot_at_epoch(state.finalized_checkpoint.epoch) if not (signed_beacon_block.message.slot > dag.finalizedHead.slot): return errIgnore("BeaconBlock: slot already finalized") # [IGNORE] The block is the first block with valid signature received for the # proposer for the slot, signed_beacon_block.message.slot. # # While this condition is similar to the proposer slashing condition at # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/phase0/validator.md#proposer-slashing # it's not identical, and this check does not address slashing: # # (1) The beacon blocks must be conflicting, i.e. different, for the same # slot and proposer. This check also catches identical blocks. # # (2) By this point in the function, it's not been checked whether they're # signed yet. As in general, expensive checks should be deferred, this # would add complexity not directly relevant this function. # # (3) As evidenced by point (1), the similarity in the validation condition # and slashing condition, while not coincidental, aren't similar enough # to combine, as one or the other might drift. # # (4) Furthermore, this function, as much as possible, simply returns a yes # or no answer, without modifying other state for p2p network interface # validation. Complicating this interface, for the sake of sharing only # couple lines of code, wouldn't be worthwhile. # # TODO might check unresolved/orphaned blocks too, and this might not see all # blocks at a given slot (though, in theory, those get checked elsewhere), or # adding metrics that count how often these conditions occur. if dag.containsForkBlock(signed_beacon_block.root): # The gossip algorithm itself already does one round of hashing to find # already-seen data, but it is fairly aggressive about forgetting about # what it has seen already # "[IGNORE] The block is the first block ..." return errIgnore("BeaconBlock: already seen") let slotBlock = getBlockIdAtSlot(dag, signed_beacon_block.message.slot) if slotBlock.isSome() and slotBlock.get().isProposed() and slotBlock.get().bid.slot == signed_beacon_block.message.slot: let curBlock = dag.getForkedBlock(slotBlock.get().bid) if curBlock.isOk(): let data = curBlock.get() if getForkedBlockField(data, proposer_index) == signed_beacon_block.message.proposer_index and data.signature.toRaw() != signed_beacon_block.signature.toRaw(): return errIgnore("BeaconBlock: already proposed in the same slot") # [IGNORE] The block's parent (defined by block.parent_root) has been seen # (via both gossip and non-gossip sources) (a client MAY queue blocks for # processing once the parent block is retrieved). # # [REJECT] The block's parent (defined by block.parent_root) # passes validation. let parent = dag.getBlockRef(signed_beacon_block.message.parent_root).valueOr: if signed_beacon_block.message.parent_root in quarantine[].unviable: quarantine[].addUnviable(signed_beacon_block.root) # https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/bellatrix/p2p-interface.md#beacon_block # `is_execution_enabled(state, block.body)` check, but unlike in # validateBeaconBlockBellatrix() don't have parent BlockRef. if signed_beacon_block.message.is_execution_block: # Blocks with execution enabled will be permitted to propagate # regardless of the validity of the execution payload. This prevents # network segregation between optimistic and non-optimistic nodes. # # If execution_payload verification of block's parent by an execution # node is not complete: # # - [REJECT] The block's parent (defined by `block.parent_root`) passes # all validation (excluding execution node verification of the # `block.body.execution_payload`). # # otherwise: # # - [IGNORE] The block's parent (defined by `block.parent_root`) passes # all validation (including execution node verification of the # `block.body.execution_payload`). # Implementation restrictions: # # - We don't know if the parent state had execution enabled. # If it had, and the block doesn't have it enabled anymore, # we end up in the pre-Merge path below (`else`) and REJECT. # Such a block is clearly invalid, though, without asking the EL. # # - We know that the parent was marked unviable, but don't know # whether it was marked unviable due to consensus (REJECT) or # execution (IGNORE) verification failure. We err on the IGNORE side. return errIgnore("BeaconBlock: ignored, parent from unviable fork") else: # [REJECT] The block's parent (defined by `block.parent_root`) passes # validation. return dag.checkedReject( "BeaconBlock: rejected, parent from unviable fork") # When the parent is missing, we can't validate the block - we'll queue it # in the quarantine for later processing if (let r = quarantine[].addOrphan( dag.finalizedHead.slot, ForkedSignedBeaconBlock.init(signed_beacon_block)); r.isErr): debug "validateBeaconBlock: could not add orphan", blockRoot = shortLog(signed_beacon_block.root), blck = shortLog(signed_beacon_block.message), err = r.error() else: debug "Block quarantined", blockRoot = shortLog(signed_beacon_block.root), blck = shortLog(signed_beacon_block.message), signature = shortLog(signed_beacon_block.signature) return errIgnore("BeaconBlock: parent not found") # Continues block parent validity checking in optimistic case, where it does # appear as a `BlockRef` (and not handled above) but isn't usable for gossip # validation. validateBeaconBlockBellatrix(signed_beacon_block, parent) # [REJECT] The block is from a higher slot than its parent. if not (signed_beacon_block.message.slot > parent.bid.slot): return dag.checkedReject( "BeaconBlock: block not from higher slot than its parent") # [REJECT] The current finalized_checkpoint is an ancestor of block -- i.e. # get_ancestor(store, block.parent_root, # compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)) == # store.finalized_checkpoint.root let finalized_checkpoint = getStateField(dag.headState, finalized_checkpoint) ancestor = get_ancestor(parent, finalized_checkpoint.epoch.start_slot) if ancestor.isNil: # This shouldn't happen: we should always be able to trace the parent back # to the finalized checkpoint (else it wouldn't be in the DAG) return errIgnore("BeaconBlock: Can't find ancestor") if not ( finalized_checkpoint.root == ancestor.root or finalized_checkpoint.root.isZero): quarantine[].addUnviable(signed_beacon_block.root) return dag.checkedReject( "BeaconBlock: Finalized checkpoint not an ancestor") # [REJECT] The block is proposed by the expected proposer_index for the # block's slot in the context of the current shuffling (defined by # parent_root/slot). If the proposer_index cannot immediately be verified # against the expected shuffling, the block MAY be queued for later # processing while proposers for the block's branch are calculated -- in such # a case do not REJECT, instead IGNORE this message. let proposer = getProposer( dag, parent, signed_beacon_block.message.slot).valueOr: warn "cannot compute proposer for block" return errIgnore("BeaconBlock: Cannot compute proposer") # internal issue if uint64(proposer) != signed_beacon_block.message.proposer_index: quarantine[].addUnviable(signed_beacon_block.root) return dag.checkedReject("BeaconBlock: Unexpected proposer") # [REJECT] The proposer signature, signed_beacon_block.signature, is valid # with respect to the proposer_index pubkey. if not verify_block_signature( dag.forkAtEpoch(signed_beacon_block.message.slot.epoch), getStateField(dag.headState, genesis_validators_root), signed_beacon_block.message.slot, signed_beacon_block.root, dag.validatorKey(proposer).get(), signed_beacon_block.signature): quarantine[].addUnviable(signed_beacon_block.root) return dag.checkedReject("BeaconBlock: Invalid proposer signature") ok() # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/phase0/p2p-interface.md#beacon_attestation_subnet_id # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/deneb/p2p-interface.md#beacon_aggregate_and_proof proc validateAttestation*( pool: ref AttestationPool, batchCrypto: ref BatchCrypto, attestation: Attestation, wallTime: BeaconTime, subnet_id: SubnetId, checkSignature: bool): Future[Result[ tuple[attesting_index: ValidatorIndex, sig: CookedSig], ValidationError]] {.async: (raises: [CancelledError]).} = # Some of the checks below have been reordered compared to the spec, to # perform the cheap checks first - in particular, we want to avoid loading # an `EpochRef` and checking signatures. This reordering might lead to # different IGNORE/REJECT results in turn affecting gossip scores. # [REJECT] The attestation's epoch matches its target -- i.e. # attestation.data.target.epoch == # compute_epoch_at_slot(attestation.data.slot) let slot = block: let v = check_attestation_slot_target(attestation.data) if v.isErr(): return pool.checkedReject(v.error()) v.get() # attestation.data.slot is within the last ATTESTATION_PROPAGATION_SLOT_RANGE # slots (within a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance) -- i.e. # attestation.data.slot + ATTESTATION_PROPAGATION_SLOT_RANGE >= current_slot # >= attestation.data.slot (a client MAY queue future attestations for # processing at the appropriate slot). # # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.2/specs/deneb/p2p-interface.md#beacon_attestation_subnet_id # modifies this for Deneb and newer forks. block: let v = check_propagation_slot_range( pool.dag.cfg.consensusForkAtEpoch(wallTime.slotOrZero.epoch), slot, wallTime) if v.isErr(): # [IGNORE] return err(v.error()) # The attestation is unaggregated -- that is, it has exactly one # participating validator (len([bit for bit in attestation.aggregation_bits # if bit == 0b1]) == 1). block: let v = check_aggregation_count(attestation, singular = true) if v.isErr(): # [REJECT] return pool.checkedReject(v.error) # The block being voted for (attestation.data.beacon_block_root) has been seen # (via both gossip and non-gossip sources) (a client MAY queue attestations # for processing once block is retrieved). # [REJECT] The block being voted for (attestation.data.beacon_block_root) # passes validation. # [IGNORE] if block is unseen so far and enqueue it in missing blocks let target = block: let v = check_beacon_and_target_block(pool[], attestation.data) if v.isErr(): # [IGNORE/REJECT] return pool.checkedResult(v.error) v.get() # The following rule follows implicitly from that we clear out any # unviable blocks from the chain dag: # # [IGNORE] The current finalized_checkpoint is an ancestor of the block # defined by attestation.data.beacon_block_root -- i.e. # get_checkpoint_block(store, attestation.data.beacon_block_root, # store.finalized_checkpoint.epoch) == store.finalized_checkpoint.root let shufflingRef = pool.dag.getShufflingRef(target.blck, target.slot.epoch, false).valueOr: # Target is verified - shouldn't happen warn "No shuffling for attestation - report bug", attestation = shortLog(attestation), target = shortLog(target) return errIgnore("Attestation: no shuffling") # [REJECT] The committee index is within the expected range -- i.e. # data.index < get_committee_count_per_slot(state, data.target.epoch). let committee_index = block: let idx = shufflingRef.get_committee_index(attestation.data.index) if idx.isErr(): return pool.checkedReject( "Attestation: committee index not within expected range") idx.get() # [REJECT] The attestation is for the correct subnet -- i.e. # compute_subnet_for_attestation(committees_per_slot, # attestation.data.slot, attestation.data.index) == subnet_id, where # committees_per_slot = get_committee_count_per_slot(state, # attestation.data.target.epoch), which may be pre-computed along with the # committee information for the signature check. block: let v = check_attestation_subnet( shufflingRef, attestation.data.slot, committee_index, subnet_id) if v.isErr(): # [REJECT] return pool.checkedReject(v.error) # [REJECT] The number of aggregation bits matches the committee size -- i.e. # len(attestation.aggregation_bits) == len(get_beacon_committee(state, # data.slot, data.index)). # # This uses the same epochRef as data.target.epoch, because the attestation's # epoch matches its target and attestation.data.target.root is an ancestor of # attestation.data.beacon_block_root. if not attestation.aggregation_bits.compatible_with_shuffling( shufflingRef, slot, committee_index): return pool.checkedReject( "Attestation: number of aggregation bits and committee size mismatch") let fork = pool.dag.forkAtEpoch(attestation.data.slot.epoch) attesting_index = get_attesting_indices_one( shufflingRef, slot, committee_index, attestation.aggregation_bits) # The number of aggregation bits matches the committee size, which ensures # this condition holds. doAssert attesting_index.isSome(), "We've checked bits length and one count already" let validator_index = attesting_index.get() # There has been no other valid attestation seen on an attestation subnet # that has an identical `attestation.data.target.epoch` and participating # validator index. # Slightly modified to allow only newer attestations than were previously # seen (no point in propagating older votes) if (pool.nextAttestationEpoch.lenu64 > validator_index.uint64) and pool.nextAttestationEpoch[validator_index].subnet > attestation.data.target.epoch: return errIgnore("Attestation: Validator has already voted in epoch") let pubkey = pool.dag.validatorKey(validator_index).valueOr: # can't happen, in theory, because we checked the aggregator index above return errIgnore("Attestation: cannot find validator pubkey") # [REJECT] The signature of `attestation` is valid. # In the spec, is_valid_indexed_attestation is used to verify the signature - # here, we do a batch verification instead let sig = if checkSignature: # Attestation signatures are batch-verified let deferredCrypto = batchCrypto .scheduleAttestationCheck( fork, attestation.data, pubkey, attestation.signature) if deferredCrypto.isErr(): return pool.checkedReject(deferredCrypto.error) let (cryptoFut, sig) = deferredCrypto.get() # Await the crypto check let x = (await cryptoFut) case x of BatchResult.Invalid: return pool.checkedReject("Attestation: invalid signature") of BatchResult.Timeout: beacon_attestations_dropped_queue_full.inc() return errIgnore("Attestation: timeout checking signature") of BatchResult.Valid: sig # keep going only in this case else: attestation.signature.load().valueOr: return pool.checkedReject("Attestation: unable to load signature") # Only valid attestations go in the list, which keeps validator_index # in range if not (pool.nextAttestationEpoch.lenu64 > validator_index.uint64): pool.nextAttestationEpoch.setLen(validator_index.int + 1) pool.nextAttestationEpoch[validator_index].subnet = attestation.data.target.epoch + 1 return ok((validator_index, sig)) # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/phase0/p2p-interface.md#beacon_aggregate_and_proof # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/deneb/p2p-interface.md#beacon_aggregate_and_proof proc validateAggregate*( pool: ref AttestationPool, batchCrypto: ref BatchCrypto, signedAggregateAndProof: SignedAggregateAndProof, wallTime: BeaconTime, checkSignature = true, checkCover = true): Future[Result[ tuple[attestingIndices: seq[ValidatorIndex], sig: CookedSig], ValidationError]] {.async: (raises: [CancelledError]).} = # Some of the checks below have been reordered compared to the spec, to # perform the cheap checks first - in particular, we want to avoid loading # an `EpochRef` and checking signatures. This reordering might lead to # different IGNORE/REJECT results in turn affecting gossip scores. template aggregate_and_proof: untyped = signedAggregateAndProof.message template aggregate: untyped = aggregate_and_proof.aggregate # [REJECT] The aggregate attestation's epoch matches its target -- i.e. # `aggregate.data.target.epoch == compute_epoch_at_slot(aggregate.data.slot)` let slot = block: let v = check_attestation_slot_target(aggregate.data) if v.isErr(): return pool.checkedReject(v.error) v.get() # [IGNORE] aggregate.data.slot is within the last # ATTESTATION_PROPAGATION_SLOT_RANGE slots (with a # MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance) -- i.e. aggregate.data.slot + # ATTESTATION_PROPAGATION_SLOT_RANGE >= current_slot >= aggregate.data.slot # # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.2/specs/deneb/p2p-interface.md#beacon_aggregate_and_proof # modifies this for Deneb and newer forks. block: let v = check_propagation_slot_range( pool.dag.cfg.consensusForkAtEpoch(wallTime.slotOrZero.epoch), slot, wallTime) if v.isErr(): # [IGNORE] return err(v.error()) # [IGNORE] The aggregate is the first valid aggregate received for the # aggregator with index aggregate_and_proof.aggregator_index for the epoch # aggregate.data.target.epoch. # Slightly modified to allow only newer attestations than were previously # seen (no point in propagating older votes) if (pool.nextAttestationEpoch.lenu64 > aggregate_and_proof.aggregator_index) and pool.nextAttestationEpoch[ aggregate_and_proof.aggregator_index].aggregate > aggregate.data.target.epoch: return errIgnore("Aggregate: validator has already aggregated in epoch") # [REJECT] The attestation has participants -- that is, # len(get_attesting_indices(state, aggregate.data, aggregate.aggregation_bits)) >= 1. # # get_attesting_indices() is: # committee = get_beacon_committee(state, data.slot, data.index) # return set(index for i, index in enumerate(committee) if bits[i]) # # the attestation doesn't have participants is iff either: # (1) the aggregation bits are all 0; or # (2) the non-zero aggregation bits don't overlap with extant committee # members, i.e. they counts don't match. # But (2) would reflect an invalid aggregation in other ways, so reject it # either way. block: let v = check_aggregation_count(aggregate, singular = false) if v.isErr(): # [REJECT] return pool.checkedReject(v.error) # [REJECT] The block being voted for (aggregate.data.beacon_block_root) # passes validation. # [IGNORE] if block is unseen so far and enqueue it in missing blocks let target = block: let v = check_beacon_and_target_block(pool[], aggregate.data) if v.isErr(): # [IGNORE/REJECT] return pool.checkedResult(v.error) v.get() let shufflingRef = pool.dag.getShufflingRef(target.blck, target.slot.epoch, false).valueOr: # Target is verified - shouldn't happen warn "No shuffling for attestation - report bug", aggregate = shortLog(aggregate), target = shortLog(target) return errIgnore("Aggregate: no shuffling") # [REJECT] The committee index is within the expected range -- i.e. # data.index < get_committee_count_per_slot(state, data.target.epoch). let committee_index = block: let idx = shufflingRef.get_committee_index(aggregate.data.index) if idx.isErr(): return pool.checkedReject( "Attestation: committee index not within expected range") idx.get() if not aggregate.aggregation_bits.compatible_with_shuffling( shufflingRef, slot, committee_index): return pool.checkedReject( "Aggregate: number of aggregation bits and committee size mismatch") if checkCover and pool[].covers(aggregate.data, aggregate.aggregation_bits): # [IGNORE] A valid aggregate attestation defined by # `hash_tree_root(aggregate.data)` whose `aggregation_bits` is a non-strict # superset has _not_ already been seen. # https://github.com/ethereum/consensus-specs/pull/2847 return errIgnore("Aggregate: already covered") # [REJECT] aggregate_and_proof.selection_proof selects the validator as an # aggregator for the slot -- i.e. is_aggregator(state, aggregate.data.slot, # aggregate.data.index, aggregate_and_proof.selection_proof) returns True. if not is_aggregator( shufflingRef, slot, committee_index, aggregate_and_proof.selection_proof): return pool.checkedReject("Aggregate: incorrect aggregator") # [REJECT] The aggregator's validator index is within the committee -- i.e. # aggregate_and_proof.aggregator_index in get_beacon_committee(state, # aggregate.data.slot, aggregate.data.index). let aggregator_index = ValidatorIndex.init(aggregate_and_proof.aggregator_index).valueOr: return pool.checkedReject("Aggregate: invalid aggregator index") if aggregator_index notin get_beacon_committee(shufflingRef, slot, committee_index): return pool.checkedReject( "Aggregate: aggregator's validator index not in committee") # 1. [REJECT] The aggregate_and_proof.selection_proof is a valid signature # of the aggregate.data.slot by the validator with index # aggregate_and_proof.aggregator_index. # get_slot_signature(state, aggregate.data.slot, privkey) # 2. [REJECT] The aggregator signature, # signed_aggregate_and_proof.signature, is valid. # 3. [REJECT] The signature of aggregate is valid. let fork = pool.dag.forkAtEpoch(aggregate.data.slot.epoch) attesting_indices = get_attesting_indices( shufflingRef, slot, committee_index, aggregate.aggregation_bits) let sig = if checkSignature: let deferredCrypto = batchCrypto .scheduleAggregateChecks( fork, signedAggregateAndProof, pool.dag, attesting_indices ) if deferredCrypto.isErr(): return pool.checkedReject(deferredCrypto.error) let (aggregatorFut, slotFut, aggregateFut, sig) = deferredCrypto.get() block: # [REJECT] The aggregator signature, # signed_aggregate_and_proof.signature, is valid. let x = await aggregatorFut case x of BatchResult.Invalid: return pool.checkedReject("Aggregate: invalid aggregator signature") of BatchResult.Timeout: beacon_aggregates_dropped_queue_full.inc() return errIgnore("Aggregate: timeout checking aggregator signature") of BatchResult.Valid: discard block: # [REJECT] aggregate_and_proof.selection_proof let x = await slotFut case x of BatchResult.Invalid: return pool.checkedReject("Aggregate: invalid slot signature") of BatchResult.Timeout: beacon_aggregates_dropped_queue_full.inc() return errIgnore("Aggregate: timeout checking slot signature") of BatchResult.Valid: discard block: # [REJECT] The aggregator signature, # signed_aggregate_and_proof.signature, is valid. let x = await aggregateFut case x of BatchResult.Invalid: return pool.checkedReject("Aggregate: invalid aggregate signature") of BatchResult.Timeout: beacon_aggregates_dropped_queue_full.inc() return errIgnore("Aggregate: timeout checking aggregate signature") of BatchResult.Valid: discard sig else: aggregate.signature.load().valueOr: return pool.checkedReject("Aggregate: unable to load signature") # The following rule follows implicitly from that we clear out any # unviable blocks from the chain dag: # # [IGNORE] The current finalized_checkpoint is an ancestor of the block # defined by aggregate.data.beacon_block_root -- i.e. # get_checkpoint_block(store, aggregate.data.beacon_block_root, # finalized_checkpoint.epoch) == store.finalized_checkpoint.root # Only valid aggregates go in the list if pool.nextAttestationEpoch.lenu64 <= aggregate_and_proof.aggregator_index: pool.nextAttestationEpoch.setLen( aggregate_and_proof.aggregator_index.int + 1) pool.nextAttestationEpoch[aggregate_and_proof.aggregator_index].aggregate = aggregate.data.target.epoch + 1 return ok((attesting_indices, sig)) # https://github.com/ethereum/consensus-specs/blob/v1.4.0/specs/capella/p2p-interface.md#bls_to_execution_change proc validateBlsToExecutionChange*( pool: ValidatorChangePool, batchCrypto: ref BatchCrypto, signed_address_change: SignedBLSToExecutionChange, wallEpoch: Epoch): Future[Result[void, ValidationError]] {.async: (raises: [CancelledError]).} = # [IGNORE] `current_epoch >= CAPELLA_FORK_EPOCH`, where `current_epoch` is # defined by the current wall-clock time. if not (wallEpoch >= pool.dag.cfg.CAPELLA_FORK_EPOCH): return errIgnore( "SignedBLSToExecutionChange: not accepting gossip until Capella") # [IGNORE] The `signed_bls_to_execution_change` is the first valid signed bls # to execution change received for the validator with index # `signed_bls_to_execution_change.message.validator_index`. if pool.isSeen(signed_address_change): return errIgnore( "SignedBLSToExecutionChange: not first valid change for validator index") # [REJECT] All of the conditions within `process_bls_to_execution_change` # pass validation. withState(pool.dag.headState): when consensusFork < ConsensusFork.Capella: return errIgnore( "SignedBLSToExecutionChange: can't validate against pre-Capella state") else: let res = check_bls_to_execution_change( pool.dag.cfg.genesisFork, forkyState.data, signed_address_change, {skipBlsValidation}) if res.isErr: return pool.checkedReject(res.error) # BLS to execution change signatures are batch-verified let deferredCrypto = batchCrypto.scheduleBlsToExecutionChangeCheck( pool.dag.cfg.genesisFork, signed_address_change) if deferredCrypto.isErr(): return pool.checkedReject(deferredCrypto.error) let (cryptoFut, _) = deferredCrypto.get() case await cryptoFut of BatchResult.Invalid: return pool.checkedReject( "SignedBLSToExecutionChange: invalid signature") of BatchResult.Timeout: return errIgnore( "SignedBLSToExecutionChange: timeout checking signature") of BatchResult.Valid: discard # keep going only in this case # Send notification about new BLS to execution change via callback if not(isNil(pool.onBLSToExecutionChangeReceived)): pool.onBLSToExecutionChangeReceived(signed_address_change) return ok() # https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/phase0/p2p-interface.md#attester_slashing proc validateAttesterSlashing*( pool: ValidatorChangePool, attester_slashing: AttesterSlashing): Result[void, ValidationError] = # [IGNORE] At least one index in the intersection of the attesting indices of # each attestation has not yet been seen in any prior attester_slashing (i.e. # attester_slashed_indices = set(attestation_1.attesting_indices).intersection(attestation_2.attesting_indices), # verify if any(attester_slashed_indices.difference(prior_seen_attester_slashed_indices))). if pool.isSeen(attester_slashing): return errIgnore( "AttesterSlashing: attester-slashed index already attester-slashed") # [REJECT] All of the conditions within process_attester_slashing pass # validation. let attester_slashing_validity = check_attester_slashing(pool.dag.headState, attester_slashing, {}) if attester_slashing_validity.isErr: return pool.checkedReject(attester_slashing_validity.error) # Send notification about new attester slashing via callback if not(isNil(pool.onAttesterSlashingReceived)): pool.onAttesterSlashingReceived(attester_slashing) ok() # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.4/specs/phase0/p2p-interface.md#proposer_slashing proc validateProposerSlashing*( pool: ValidatorChangePool, proposer_slashing: ProposerSlashing): Result[void, ValidationError] = # Not from spec; the rest of NBC wouldn't have correctly processed it either. if proposer_slashing.signed_header_1.message.proposer_index > int.high.uint64: return errIgnore("ProposerSlashing: proposer-slashed index too high") # [IGNORE] The proposer slashing is the first valid proposer slashing # received for the proposer with index # proposer_slashing.signed_header_1.message.proposer_index. if pool.isSeen(proposer_slashing): return errIgnore( "ProposerSlashing: proposer-slashed index already proposer-slashed") # [REJECT] All of the conditions within process_proposer_slashing # pass validation. let proposer_slashing_validity = check_proposer_slashing(pool.dag.headState, proposer_slashing, {}) if proposer_slashing_validity.isErr: return pool.checkedReject(proposer_slashing_validity.error) # Send notification about new proposer slashing via callback if not(isNil(pool.onProposerSlashingReceived)): pool.onProposerSlashingReceived(proposer_slashing) ok() # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#voluntary_exit proc validateVoluntaryExit*( pool: ValidatorChangePool, signed_voluntary_exit: SignedVoluntaryExit): Result[void, ValidationError] = # [IGNORE] The voluntary exit is the first valid voluntary exit received for # the validator with index signed_voluntary_exit.message.validator_index. if signed_voluntary_exit.message.validator_index >= getStateField(pool.dag.headState, validators).lenu64: return errIgnore("VoluntaryExit: validator index too high") # Given that getStateField(pool.dag.headState, validators) is a seq, # signed_voluntary_exit.message.validator_index.int is already valid, but # check explicitly if one changes that data structure. if pool.isSeen(signed_voluntary_exit): return errIgnore( "VoluntaryExit: validator index already voluntarily exited") # [REJECT] All of the conditions within process_voluntary_exit pass # validation. let voluntary_exit_validity = check_voluntary_exit( pool.dag.cfg, pool.dag.headState, signed_voluntary_exit, {}) if voluntary_exit_validity.isErr: return pool.checkedReject(voluntary_exit_validity.error) # Send notification about new voluntary exit via callback if not(isNil(pool.onVoluntaryExitReceived)): pool.onVoluntaryExitReceived(signed_voluntary_exit) ok() # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.1/specs/altair/p2p-interface.md#sync_committee_subnet_id proc validateSyncCommitteeMessage*( dag: ChainDAGRef, quarantine: ref Quarantine, batchCrypto: ref BatchCrypto, syncCommitteeMsgPool: ref SyncCommitteeMsgPool, msg: SyncCommitteeMessage, subcommitteeIdx: SyncSubcommitteeIndex, wallTime: BeaconTime, checkSignature: bool): Future[Result[ (BlockId, CookedSig, seq[uint64]), ValidationError]] {.async: (raises: [CancelledError]).} = block: # [IGNORE] The message's slot is for the current slot (with a # `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance), i.e. # `sync_committee_message.slot == current_slot`. let v = check_slot_exact(msg.slot, wallTime) if v.isErr(): return err(v.error()) # [REJECT] The subnet_id is valid for the given validator # i.e. subnet_id in compute_subnets_for_sync_committee(state, sync_committee_message.validator_index). # Note this validation implies the validator is part of the broader # current sync committee along with the correct subcommittee. # This check also ensures that the validator index is in range let positionsInSubcommittee = dag.getSubcommitteePositions( msg.slot + 1, subcommitteeIdx, msg.validator_index) if positionsInSubcommittee.len == 0: return dag.checkedReject( "SyncCommitteeMessage: originator not part of sync committee") # [IGNORE] The block being signed (`sync_committee_message.beacon_block_root`) # has been seen (via both gossip and non-gossip sources) (a client MAY queue # sync committee messages for processing once block is received) # [REJECT] The block being signed (`sync_committee_message.beacon_block_root`) # passes validation. let blockRoot = msg.beacon_block_root blck = dag.getBlockRef(blockRoot).valueOr: if blockRoot in quarantine[].unviable: return dag.checkedReject("SyncCommitteeMessage: target invalid") quarantine[].addMissing(blockRoot) return errIgnore("SyncCommitteeMessage: target not found") block: # [IGNORE] There has been no other valid sync committee message for the # declared `slot` for the validator referenced by # `sync_committee_message.validator_index` # # Note this validation is per topic so that for a given slot, multiple # messages could be forwarded with the same validator_index as long as # the subnet_ids are distinct. if syncCommitteeMsgPool[].isSeen(msg, subcommitteeIdx, dag.head.bid): return errIgnore("SyncCommitteeMessage: duplicate message") # [REJECT] The signature is valid for the message beacon_block_root for the # validator referenced by validator_index. let senderPubKey = dag.validatorKey(msg.validator_index).valueOr: return dag.checkedReject("SyncCommitteeMessage: invalid validator index") let sig = if checkSignature: # Attestation signatures are batch-verified let deferredCrypto = batchCrypto .scheduleSyncCommitteeMessageCheck( dag.forkAtEpoch(msg.slot.epoch), msg.slot, msg.beacon_block_root, senderPubKey, msg.signature) if deferredCrypto.isErr(): return dag.checkedReject(deferredCrypto.error) # Await the crypto check let (cryptoFut, sig) = deferredCrypto.get() let x = (await cryptoFut) case x of BatchResult.Invalid: return dag.checkedReject("SyncCommitteeMessage: invalid signature") of BatchResult.Timeout: beacon_sync_messages_dropped_queue_full.inc() return errIgnore("SyncCommitteeMessage: timeout checking signature") of BatchResult.Valid: sig # keep going only in this case else: msg.signature.load().valueOr: return dag.checkedReject( "SyncCommitteeMessage: unable to load signature") return ok((blck.bid, sig, positionsInSubcommittee)) # https://github.com/ethereum/consensus-specs/blob/v1.3.0/specs/altair/p2p-interface.md#sync_committee_contribution_and_proof proc validateContribution*( dag: ChainDAGRef, quarantine: ref Quarantine, batchCrypto: ref BatchCrypto, syncCommitteeMsgPool: ref SyncCommitteeMsgPool, msg: SignedContributionAndProof, wallTime: BeaconTime, checkSignature: bool ): Future[Result[ (BlockId, CookedSig, seq[ValidatorIndex]), ValidationError]] {.async: (raises: [CancelledError]).} = block: # [IGNORE] The contribution's slot is for the current slot # (with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance) # i.e. contribution.slot == current_slot. let v = check_slot_exact(msg.message.contribution.slot, wallTime) if v.isErr(): # [IGNORE] return err(v.error()) # [REJECT] The subcommittee index is in the allowed range # i.e. contribution.subcommittee_index < SYNC_COMMITTEE_SUBNET_COUNT. let subcommitteeIdx = SyncSubcommitteeIndex.init( msg.message.contribution.subcommittee_index).valueOr: return dag.checkedReject("Contribution: subcommittee index too high") # [REJECT] The contribution has participants # that is, any(contribution.aggregation_bits). if msg.message.contribution.aggregation_bits.isZeros: return dag.checkedReject("Contribution: aggregation bits empty") # [REJECT] contribution_and_proof.selection_proof selects the validator # as an aggregator for the slot # i.e. is_sync_committee_aggregator(contribution_and_proof.selection_proof) # returns True. if not is_sync_committee_aggregator(msg.message.selection_proof): return dag.checkedReject("Contribution: invalid selection_proof") # [IGNORE] The sync committee contribution is the first valid # contribution received for the aggregator with index # contribution_and_proof.aggregator_index for the slot contribution.slot # and subcommittee index contribution.subcommittee_index # (this requires maintaining a cache of size SYNC_COMMITTEE_SIZE for this # topic that can be flushed after each slot). if syncCommitteeMsgPool[].isSeen(msg.message): return errIgnore("Contribution: validator has already aggregated in slot") # [REJECT] The aggregator's validator index is in the declared subcommittee # of the current sync committee. # i.e. state.validators[contribution_and_proof.aggregator_index].pubkey in # get_sync_subcommittee_pubkeys(state, contribution.subcommittee_index). let aggregator_index = ValidatorIndex.init(msg.message.aggregator_index).valueOr: return dag.checkedReject("Contribution: invalid aggregator index") # TODO we take a copy of the participants to avoid the data going stale # between validation and use - nonetheless, a design that avoids it and # stays safe would be nice participants = dag.syncCommitteeParticipants( msg.message.contribution.slot + 1, subcommitteeIdx) if aggregator_index notin participants: return dag.checkedReject("Contribution: aggregator not in subcommittee") # [IGNORE] The block being signed # (`contribution_and_proof.contribution.beacon_block_root`) has been seen # (via both gossip and non-gossip sources) (a client MAY queue sync committee # contributions for processing once block is received) # [REJECT] The block being signed # (`contribution_and_proof.contribution.beacon_block_root`) passes validation. let blockRoot = msg.message.contribution.beacon_block_root blck = dag.getBlockRef(blockRoot).valueOr: if blockRoot in quarantine[].unviable: return dag.checkedReject("Contribution: target invalid") quarantine[].addMissing(blockRoot) return errIgnore("Contribution: target not found") # [IGNORE] A valid sync committee contribution with equal `slot`, # `beacon_block_root` and `subcommittee_index` whose `aggregation_bits` # is non-strict superset has _not_ already been seen. if syncCommitteeMsgPool[].covers(msg.message.contribution, blck.bid): return errIgnore("Contribution: already covered") let sig = if checkSignature: let deferredCrypto = batchCrypto.scheduleContributionChecks( dag.forkAtEpoch(msg.message.contribution.slot.epoch), msg, subcommitteeIdx, dag) if deferredCrypto.isErr(): return dag.checkedReject(deferredCrypto.error) let (aggregatorFut, proofFut, contributionFut, sig) = deferredCrypto.get() block: # [REJECT] The aggregator signature, # `signed_contribution_and_proof.signature`, is valid. let x = await aggregatorFut case x of BatchResult.Invalid: return dag.checkedReject( "Contribution: invalid aggregator signature") of BatchResult.Timeout: beacon_contributions_dropped_queue_full.inc() return errIgnore( "Contribution: timeout checking aggregator signature") of BatchResult.Valid: discard block: # [REJECT] The `contribution_and_proof.selection_proof` # is a valid signature of the `SyncAggregatorSelectionData` # derived from the `contribution` by the validator with index # `contribution_and_proof.aggregator_index`. let x = await proofFut case x of BatchResult.Invalid: return dag.checkedReject("Contribution: invalid proof") of BatchResult.Timeout: beacon_contributions_dropped_queue_full.inc() return errIgnore("Contribution: timeout checking proof") of BatchResult.Valid: discard block: # [REJECT] The aggregate signature is valid for the message # `beacon_block_root` and aggregate pubkey derived from the # participation info in `aggregation_bits` for the subcommittee # specified by the `contribution.subcommittee_index`. let x = await contributionFut case x of BatchResult.Invalid: return dag.checkedReject( "Contribution: invalid contribution signature") of BatchResult.Timeout: beacon_contributions_dropped_queue_full.inc() return errIgnore( "Contribution: timeout checking contribution signature") of BatchResult.Valid: discard sig else: msg.message.contribution.signature.load().valueOr: return dag.checkedReject("SyncCommitteeMessage: unable to load signature") return ok((blck.bid, sig, participants)) # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/altair/light-client/p2p-interface.md#light_client_finality_update proc validateLightClientFinalityUpdate*( pool: var LightClientPool, dag: ChainDAGRef, finality_update: ForkedLightClientFinalityUpdate, wallTime: BeaconTime): Result[void, ValidationError] = # [IGNORE] The `finalized_header.beacon.slot` is greater than that of all # previously forwarded `finality_update`s, or it matches the highest # previously forwarded slot and also has a `sync_aggregate` indicating # supermajority (> 2/3) sync committee participation while the previously # forwarded `finality_update` for that slot did not indicate supermajority let finalized_slot = withForkyFinalityUpdate(finality_update): when lcDataFork > LightClientDataFork.None: forkyFinalityUpdate.finalized_header.beacon.slot else: GENESIS_SLOT if finalized_slot < pool.latestForwardedFinalitySlot: return errIgnore("LightClientFinalityUpdate: slot already forwarded") let has_supermajority = withForkyFinalityUpdate(finality_update): when lcDataFork > LightClientDataFork.None: forkyFinalityUpdate.sync_aggregate.hasSupermajoritySyncParticipation else: false if finalized_slot == pool.latestForwardedFinalitySlot: if pool.latestForwardedFinalityHasSupermajority: return errIgnore("LightClientFinalityUpdate: already have supermajority") if not has_supermajority: return errIgnore("LightClientFinalityUpdate: no new supermajority") let signature_slot = withForkyFinalityUpdate(finality_update): when lcDataFork > LightClientDataFork.None: forkyFinalityUpdate.signature_slot else: GENESIS_SLOT currentTime = wallTime + MAXIMUM_GOSSIP_CLOCK_DISPARITY forwardTime = signature_slot.light_client_finality_update_time if currentTime < forwardTime: # [IGNORE] The `finality_update` is received after the block at # `signature_slot` was given enough time to propagate through the network. return errIgnore("LightClientFinalityUpdate: received too early") if not finality_update.matches(dag.lcDataStore.cache.latest): # [IGNORE] The received `finality_update` matches the locally computed one # exactly. return errIgnore("LightClientFinalityUpdate: not matching local") pool.latestForwardedFinalitySlot = finalized_slot pool.latestForwardedFinalityHasSupermajority = has_supermajority ok() # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/altair/light-client/p2p-interface.md#light_client_optimistic_update proc validateLightClientOptimisticUpdate*( pool: var LightClientPool, dag: ChainDAGRef, optimistic_update: ForkedLightClientOptimisticUpdate, wallTime: BeaconTime): Result[void, ValidationError] = let attested_slot = withForkyOptimisticUpdate(optimistic_update): when lcDataFork > LightClientDataFork.None: forkyOptimisticUpdate.attested_header.beacon.slot else: GENESIS_SLOT if attested_slot <= pool.latestForwardedOptimisticSlot: # [IGNORE] The `attested_header.beacon.slot` is greater than that of all # previously forwarded `optimistic_update`s return errIgnore("LightClientOptimisticUpdate: slot already forwarded") let signature_slot = withForkyOptimisticUpdate(optimistic_update): when lcDataFork > LightClientDataFork.None: forkyOptimisticUpdate.signature_slot else: GENESIS_SLOT currentTime = wallTime + MAXIMUM_GOSSIP_CLOCK_DISPARITY forwardTime = signature_slot.light_client_optimistic_update_time if currentTime < forwardTime: # [IGNORE] The `optimistic_update` is received after the block at # `signature_slot` was given enough time to propagate through the network. return errIgnore("LightClientOptimisticUpdate: received too early") if not optimistic_update.matches(dag.lcDataStore.cache.latest): # [IGNORE] The received `optimistic_update` matches the locally computed one # exactly. return errIgnore("LightClientOptimisticUpdate: not matching local") pool.latestForwardedOptimisticSlot = attested_slot ok()