# beacon_chain # Copyright (c) 2018-2021 Status Research & Development GmbH # Licensed and distributed under either of # * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT). # * Apache v2 license (license terms in the root directory or at https://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: [Defect].} import # Stdlib std/[typetraits, strutils, algorithm], # Status stew/[byteutils, results], serialization, json_serialization, chronicles, # Internal ../spec/datatypes/base export serialization, json_serialization # Generic sandwich https://github.com/nim-lang/Nim/issues/11225 # Slashing Protection Interop # -------------------------------------------- # We use the SPDIR type as an intermediate representation # between database versions and to generate # the serialized interchanged format. # # References: https://eips.ethereum.org/EIPS/eip-3076 # # SPDIR: Nimbus-specific, Slashing Protection Database Intermediate Representation # SPDIF: Cross-client, json, Slashing Protection Database Interchange Format type SPDIR* = object ## Slashing Protection Database Interchange Format metadata*: SPDIR_Meta data*: seq[SPDIR_Validator] Eth2Digest0x* = distinct Eth2Digest ## The spec mandates "0x" prefix on serialization ## So we need to set custom read/write PubKeyBytes* = array[RawPubKeySize, byte] ## This is the serialized byte representation ## of a Validator Public Key. ## Portable between Miracl/BLST ## and limits serialization/deserialization call PubKey0x* = distinct PubKeyBytes ## The spec mandates "0x" prefix on serialization ## So we need to set custom read/write ## We also assume that pubkeys in the database ## are valid points on the BLS12-381 G1 curve ## (so we skip fromRaw/serialization checks) SlotString* = distinct Slot ## The spec mandates string serialization for wide compatibility (javascript) EpochString* = distinct Epoch ## The spec mandates string serialization for wide compatibility (javascript) SPDIR_Meta* = object interchange_format_version*: string genesis_validators_root*: Eth2Digest0x SPDIR_Validator* = object pubkey*: PubKey0x signed_blocks*: seq[SPDIR_SignedBlock] signed_attestations*: seq[SPDIR_SignedAttestation] SPDIR_SignedBlock* = object slot*: SlotString signing_root*: Eth2Digest0x # compute_signing_root(block, domain) SPDIR_SignedAttestation* = object source_epoch*: EpochString target_epoch*: EpochString signing_root*: Eth2Digest0x # compute_signing_root(attestation, domain) # Slashing Protection types # -------------------------------------------- SlashingImportStatus* = enum siSuccess siFailure siPartial BadVoteKind* = enum ## Attestation bad vote kind # h: height (i.e. epoch for attestation, slot for blocks) # t: target # s: source # 1: existing attestations # 2: candidate attestation # Spec slashing condition DoubleVote # h(t1) == h(t2) SurroundVote # h(s1) < h(s2) < h(t2) < h(t1) or h(s2) < h(s1) < h(t1) < h(t2) # Non-spec, should never happen in a well functioning client TargetPrecedesSource # h(t1) < h(s1) - current epoch precedes last justified epoch # EIP-3067 (https://eips.ethereum.org/EIPS/eip-3076) MinSourceViolation # h(s2) < h(s1) - EIP3067 condition 4 (strict inequality) MinTargetViolation # h(t2) <= h(t1) - EIP3067 condition 5 DatabaseError # Cannot read/write the slashing protection db BadVote* {.pure.} = object case kind*: BadVoteKind of DoubleVote: existingAttestation*: Eth2Digest of SurroundVote: existingAttestationRoot*: Eth2Digest # Many roots might be in conflict sourceExisting*, targetExisting*: Epoch sourceSlashable*, targetSlashable*: Epoch of TargetPrecedesSource: discard of MinSourceViolation: minSource*: Epoch candidateSource*: Epoch of MinTargetViolation: minTarget*: Epoch candidateTarget*: Epoch of BadVoteKind.DatabaseError: message*: string BadProposalKind* {.pure.} = enum # Spec slashing condition DoubleProposal # h(t1) == h(t2) # EIP-3067 (https://eips.ethereum.org/EIPS/eip-3076) MinSlotViolation # h(t2) <= h(t1) DatabaseError # Cannot read/write the slashing protection db BadProposal* = object case kind*: BadProposalKind of DoubleProposal: existingBlock*: Eth2Digest of MinSlotViolation: minSlot*: Slot candidateSlot*: Slot of BadProposalKind.DatabaseError: message*: string func `==`*(a, b: BadVote): bool = ## Comparison operator. ## Used implictily by Result when comparing the ## result of multiple DB versions if a.kind != b.kind: false else: case a.kind of DoubleVote: a.existingAttestation == b.existingAttestation of SurroundVote: (a.existingAttestationRoot == b.existingAttestationRoot) and (a.sourceExisting == b.sourceExisting) and (a.targetExisting == b.targetExisting) and (a.sourceSlashable == b.sourceSlashable) and (a.targetSlashable == b.targetSlashable) of TargetPrecedesSource: true of MinSourceViolation: (a.minSource == b.minSource) and (a.candidateSource == b.candidateSource) of MinTargetViolation: (a.minTarget == b.minTarget) and (a.candidateTarget == b.candidateTarget) of BadVoteKind.DatabaseError: true template `==`*(a, b: PubKey0x): bool = PubKeyBytes(a) == PubKeyBytes(b) template `<`*(a, b: PubKey0x): bool = PubKeyBytes(a) < PubKeyBytes(b) template cmp*(a, b: PubKey0x): bool = cmp(PubKeyBytes(a), PubKeyBytes(b)) func `==`*(a, b: BadProposal): bool = ## Comparison operator. ## Used implictily by Result when comparing the ## result of multiple DB versions ## ## Except that V1 doesn't support low-watermark... if a.kind != b.kind: false elif a.kind == DoubleProposal: a.existingBlock == b.existingBlock elif a.kind == MinSlotViolation: a.minSlot == b.minSlot and a.candidateSlot == b.candidateSlot else: # Unreachable false # Serialization # -------------------------------------------- proc writeValue*(writer: var JsonWriter, value: PubKey0x) {.inline, raises: [IOError, Defect].} = writer.writeValue("0x" & value.PubKeyBytes.toHex()) proc readValue*(reader: var JsonReader, value: var PubKey0x) {.raises: [SerializationError, IOError, Defect].} = try: value = PubKey0x hexToByteArray(reader.readValue(string), RawPubKeySize) except ValueError: raiseUnexpectedValue(reader, "Hex string expected") proc writeValue*(w: var JsonWriter, a: Eth2Digest0x) {.inline, raises: [IOError, Defect].} = w.writeValue "0x" & a.Eth2Digest.data.toHex() proc readValue*(r: var JsonReader, a: var Eth2Digest0x) {.raises: [SerializationError, IOError, Defect].} = try: a = Eth2Digest0x fromHex(Eth2Digest, r.readValue(string)) except ValueError: raiseUnexpectedValue(r, "Hex string expected") proc writeValue*(w: var JsonWriter, a: SlotString or EpochString) {.inline, raises: [IOError, Defect].} = w.writeValue $distinctBase(a) proc readValue*(r: var JsonReader, a: var (SlotString or EpochString)) {.raises: [SerializationError, IOError, Defect].} = try: a = (typeof a)(r.readValue(string).parseBiggestUInt()) except ValueError: raiseUnexpectedValue(r, "Integer in a string expected") proc importSlashingInterchange*( db: auto, path: string): SlashingImportStatus {.raises: [Defect, IOError, SerializationError].} = ## Import a Slashing Protection Database Interchange Format ## into a Nimbus DB. ## This adds data to already existing data. let spdir = Json.loadFile(path, SPDIR) return db.inclSPDIR(spdir) # Logging # -------------------------------------------- func shortLog*(v: SPDIR_SignedBlock): auto = ( slot: shortLog(v.slot.Slot), signing_root: shortLog(v.signing_root.Eth2Digest) ) func shortLog*(v: SPDIR_SignedAttestation): auto = ( source_epoch: shortLog(v.source_epoch.Epoch), target_epoch: shortLog(v.target_epoch.Epoch), signing_root: shortLog(v.signing_root.Eth2Digest) ) chronicles.formatIt SlotString: it.Slot.shortLog chronicles.formatIt EpochString: it.Slot.shortLog chronicles.formatIt Eth2Digest0x: it.Eth2Digest.shortLog chronicles.formatIt SPDIR_SignedBlock: it.shortLog chronicles.formatIt SPDIR_SignedAttestation: it.shortLog # Interchange import # -------------------------------------------- proc importInterchangeV5Impl*( db: auto, spdir: var SPDIR ): SlashingImportStatus {.raises: [SerializationError, IOError, Defect].} = ## Common implementation of interchange import ## according to https://eips.ethereum.org/EIPS/eip-3076 ## spdir needs to be `var` as it will be sorted in-place result = siSuccess for v in 0 ..< spdir.data.len: let parsedKey = block: let key = ValidatorPubKey.fromRaw(spdir.data[v].pubkey.PubKeyBytes) if key.isErr: # The bytes does not describe a valid encoding (length error) error "Invalid public key.", pubkey = "0x" & spdir.data[v].pubkey.PubKeyBytes.toHex() result = siPartial continue if key.get().load().isNone(): # The bytes don't deserialize to a valid BLS G1 elliptic curve point. # Deserialization is costly but done only once per validator. # and SlashingDB import is a very rare event. error "Invalid public key.", pubkey = "0x" & spdir.data[v].pubkey.PubKeyBytes.toHex() result = siPartial continue key.get() # TODO: with minification sorting is unnecessary, cleanup # Sort by ascending minimum slot so that we don't trigger MinSlotViolation spdir.data[v].signed_blocks.sort do (a, b: SPDIR_SignedBlock) -> int: result = cmp(a.slot.int, b.slot.int) spdir.data[v].signed_attestations.sort do (a, b: SPDIR_SignedAttestation) -> int: result = cmp(a.source_epoch.int, b.source_epoch.int) if result == 0: # Same epoch result = cmp(a.target_epoch.int, b.target_epoch.int) const ZeroDigest = Eth2Digest() let (dbSlot, dbSource, dbTarget) = db.retrieveLatestValidatorData(parsedKey) # Blocks # --------------------------------------------------- # After import we need to prune the DB from everything # besides the last imported block slot. # This ensures that even if 2 slashing DB are imported in the wrong order # (the last before the earliest) the minSlotViolation check stays consistent. var maxValidSlotSeen = -1 if dbSlot.isSome(): maxValidSlotSeen = int dbSlot.get() if spdir.data[v].signed_blocks.len >= 1: # Minification, to limit Sqlite IO we only import the last block after sorting template B: untyped = spdir.data[v].signed_blocks[^1] let status = db.registerBlock( parsedKey, B.slot.Slot, B.signing_root.Eth2Digest ) if status.isErr(): # We might be importing a duplicate which EIP-3076 allows # there is no reason during normal operation to integrate # a duplicate so checkSlashableBlockProposal would have rejected it. # We special-case that for imports. # Note: rule 2 mentions repeat signing in the MinSlotViolation case # having 2 blocks with the same signing root and different slots # would break the blockchain so we only check for exact slot. if status.error.kind == DoubleProposal and B.signing_root.Eth2Digest != ZeroDigest and status.error.existingBlock == B.signing_root.Eth2Digest: warn "Block already exists in the DB", pubkey = spdir.data[v].pubkey.PubKeyBytes.toHex(), candidateBlock = B else: error "Slashable block. Skipping its import.", pubkey = spdir.data[v].pubkey.PubKeyBytes.toHex(), candidateBlock = B, conflict = status.error() result = siPartial if B.slot.int > maxValidSlotSeen: maxValidSlotSeen = int B.slot # Now prune everything that predates # this DB or interchange file max slot # Even if the block is not imported, pruning will keep the latest one. db.pruneBlocks(parsedKey, Slot maxValidSlotSeen) # Attestations # --------------------------------------------------- # After import we need to prune the DB from everything # besides the last imported attestation source and target epochs. # This ensures that even if 2 slashing DB are imported in the wrong order # (the last before the earliest) the minEpochViolation check stays consistent. var maxValidSourceEpochSeen = -1 var maxValidTargetEpochSeen = -1 if dbSource.isSome(): maxValidSourceEpochSeen = int dbSource.get() if dbTarget.isSome(): maxValidTargetEpochSeen = int dbTarget.get() # We do a first pass over the data to find the max source/target seen for a in 0 ..< spdir.data[v].signed_attestations.len: template A: untyped = spdir.data[v].signed_attestations[a] if A.source_epoch.int > maxValidSourceEpochSeen: maxValidSourceEpochSeen = A.source_epoch.int if A.target_epoch.int > maxValidTargetEpochSeen: maxValidTargetEpochSeen = A.target_epoch.int if maxValidSourceEpochSeen < 0 or maxValidTargetEpochSeen < 0: doAssert maxValidSourceEpochSeen == -1 and maxValidTargetEpochSeen == -1 notice "No attestation found in slashing interchange file for validator", pubkey = spdir.data[v].pubkey.PubKeyBytes.toHex() continue # See formal proof https://github.com/michaelsproul/slashing-proofs # of synthetic attestation if not(maxValidSourceEpochSeen < maxValidTargetEpochSeen) and not(maxValidSourceEpochSeen == 0 and maxValidTargetEpochSeen == 0): # Special-case genesis (Slashing prot is deactivated anyway) warn "Invalid attestation(s), source epochs should be less than target epochs, skipping import", pubkey = spdir.data[v].pubkey.PubKeyBytes.toHex(), maxValidSourceEpochSeen = maxValidSourceEpochSeen, maxValidTargetEpochSeen = maxValidTargetEpochSeen result = siPartial continue db.registerSyntheticAttestation( parsedKey, Epoch maxValidSourceEpochSeen, Epoch maxValidTargetEpochSeen ) db.pruneAttestations(parsedKey, maxValidSourceEpochSeen, maxValidTargetEpochSeen)