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fix is_valid_indexed_attestation() to check for too-high attestation indices

This commit is contained in:
Dustin Brody 2020-06-22 12:37:47 +02:00 committed by tersec
parent 47eaaa7696
commit 62a7e7fede
1 changed files with 22 additions and 12 deletions
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34
beacon_chain/spec/beaconstate.nim
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@ -392,21 +392,31 @@ proc process_registry_updates*(state: var BeaconState,
validator.activation_epoch = validator.activation_epoch =
compute_activation_exit_epoch(get_current_epoch(state)) compute_activation_exit_epoch(get_current_epoch(state))
# https://github.com/ethereum/eth2.0-specs/blob/v0.11.3/specs/phase0/beacon-chain.md#is_valid_indexed_attestation # https://github.com/ethereum/eth2.0-specs/blob/v0.12.1/specs/phase0/beacon-chain.md#is_valid_indexed_attestation
proc is_valid_indexed_attestation*( func is_valid_indexed_attestation*(
state: BeaconState, indexed_attestation: IndexedAttestation, state: BeaconState, indexed_attestation: IndexedAttestation,
flags: UpdateFlags): bool = flags: UpdateFlags): bool =
# Check if ``indexed_attestation`` has sorted and unique indices and a valid # Check if ``indexed_attestation`` is not empty, has sorted and unique
# aggregate signature. # indices and has a valid aggregate signature.
# TODO: this is noSideEffect besides logging
# https://github.com/status-im/nim-chronicles/issues/62 template is_sorted_and_unique(s: untyped): bool =
for i in 1 ..< s.len:
if s[i - 1].uint64 >= s[i].uint64:
return false
true
# Not from spec, but this function gets used in front-line roles, not just
# behind firewall.
let num_validators = state.validators.len.uint64
if anyIt(indexed_attestation.attesting_indices, it >= num_validators):
trace "indexed attestation: not all indices valid validators"
return false
# Verify indices are sorted and unique # Verify indices are sorted and unique
# TODO: A simple loop can verify that the indicates are monotonically let indices = indexed_attestation.attesting_indices.asSeq
# increasing and non-repeating here! if len(indices) == 0 or not is_sorted_and_unique(indices):
let indices = indexed_attestation.attesting_indices trace "indexed attestation: indices not sorted and unique"
if indices.asSeq != sorted(toHashSet(indices.asSeq).toSeq, system.cmp):
notice "indexed attestation: indices not sorted"
return false return false
# Verify aggregate signature # Verify aggregate signature
@ -416,7 +426,7 @@ proc is_valid_indexed_attestation*(
if not verify_attestation_signature( if not verify_attestation_signature(
state.fork, state.genesis_validators_root, indexed_attestation.data, state.fork, state.genesis_validators_root, indexed_attestation.data,
pubkeys, indexed_attestation.signature): pubkeys, indexed_attestation.signature):
notice "indexed attestation: signature verification failure" trace "indexed attestation: signature verification failure"
return false return false
true true