package types import ( "bytes" "fmt" amino "github.com/tendermint/go-amino" "github.com/tendermint/tendermint/crypto" "github.com/tendermint/tendermint/crypto/merkle" ) // ErrEvidenceInvalid wraps a piece of evidence and the error denoting how or why it is invalid. type ErrEvidenceInvalid struct { Evidence Evidence ErrorValue error } func NewEvidenceInvalidErr(ev Evidence, err error) *ErrEvidenceInvalid { return &ErrEvidenceInvalid{ev, err} } // Error returns a string representation of the error. func (err *ErrEvidenceInvalid) Error() string { return fmt.Sprintf("Invalid evidence: %v. Evidence: %v", err.ErrorValue, err.Evidence) } //------------------------------------------- // Evidence represents any provable malicious activity by a validator type Evidence interface { Height() int64 // height of the equivocation Address() []byte // address of the equivocating validator Hash() []byte // hash of the evidence Verify(chainID string, pubKey crypto.PubKey) error // verify the evidence Equal(Evidence) bool // check equality of evidence String() string } func RegisterEvidences(cdc *amino.Codec) { cdc.RegisterInterface((*Evidence)(nil), nil) cdc.RegisterConcrete(&DuplicateVoteEvidence{}, "tendermint/DuplicateVoteEvidence", nil) // mocks cdc.RegisterConcrete(MockGoodEvidence{}, "tendermint/MockGoodEvidence", nil) cdc.RegisterConcrete(MockBadEvidence{}, "tendermint/MockBadEvidence", nil) } //------------------------------------------- // DuplicateVoteEvidence contains evidence a validator signed two conflicting votes. type DuplicateVoteEvidence struct { PubKey crypto.PubKey VoteA *Vote VoteB *Vote } // String returns a string representation of the evidence. func (dve *DuplicateVoteEvidence) String() string { return fmt.Sprintf("VoteA: %v; VoteB: %v", dve.VoteA, dve.VoteB) } // Height returns the height this evidence refers to. func (dve *DuplicateVoteEvidence) Height() int64 { return dve.VoteA.Height } // Address returns the address of the validator. func (dve *DuplicateVoteEvidence) Address() []byte { return dve.PubKey.Address() } // Hash returns the hash of the evidence. func (dve *DuplicateVoteEvidence) Hash() []byte { return aminoHasher(dve).Hash() } // Verify returns an error if the two votes aren't conflicting. // To be conflicting, they must be from the same validator, for the same H/R/S, but for different blocks. func (dve *DuplicateVoteEvidence) Verify(chainID string, pubKey crypto.PubKey) error { // H/R/S must be the same if dve.VoteA.Height != dve.VoteB.Height || dve.VoteA.Round != dve.VoteB.Round || dve.VoteA.Type != dve.VoteB.Type { return fmt.Errorf("DuplicateVoteEvidence Error: H/R/S does not match. Got %v and %v", dve.VoteA, dve.VoteB) } // Address must be the same if !bytes.Equal(dve.VoteA.ValidatorAddress, dve.VoteB.ValidatorAddress) { return fmt.Errorf("DuplicateVoteEvidence Error: Validator addresses do not match. Got %X and %X", dve.VoteA.ValidatorAddress, dve.VoteB.ValidatorAddress) } // Index must be the same if dve.VoteA.ValidatorIndex != dve.VoteB.ValidatorIndex { return fmt.Errorf("DuplicateVoteEvidence Error: Validator indices do not match. Got %d and %d", dve.VoteA.ValidatorIndex, dve.VoteB.ValidatorIndex) } // BlockIDs must be different if dve.VoteA.BlockID.Equals(dve.VoteB.BlockID) { return fmt.Errorf("DuplicateVoteEvidence Error: BlockIDs are the same (%v) - not a real duplicate vote", dve.VoteA.BlockID) } // pubkey must match address (this should already be true, sanity check) addr := dve.VoteA.ValidatorAddress if !bytes.Equal(pubKey.Address(), addr) { return fmt.Errorf("DuplicateVoteEvidence FAILED SANITY CHECK - address (%X) doesn't match pubkey (%v - %X)", addr, pubKey, pubKey.Address()) } // Signatures must be valid if !pubKey.VerifyBytes(dve.VoteA.SignBytes(chainID), dve.VoteA.Signature) { return fmt.Errorf("DuplicateVoteEvidence Error verifying VoteA: %v", ErrVoteInvalidSignature) } if !pubKey.VerifyBytes(dve.VoteB.SignBytes(chainID), dve.VoteB.Signature) { return fmt.Errorf("DuplicateVoteEvidence Error verifying VoteB: %v", ErrVoteInvalidSignature) } return nil } // Equal checks if two pieces of evidence are equal. func (dve *DuplicateVoteEvidence) Equal(ev Evidence) bool { if _, ok := ev.(*DuplicateVoteEvidence); !ok { return false } // just check their hashes dveHash := aminoHasher(dve).Hash() evHash := aminoHasher(ev).Hash() return bytes.Equal(dveHash, evHash) } //----------------------------------------------------------------- // UNSTABLE type MockGoodEvidence struct { Height_ int64 Address_ []byte } // UNSTABLE func NewMockGoodEvidence(height int64, idx int, address []byte) MockGoodEvidence { return MockGoodEvidence{height, address} } func (e MockGoodEvidence) Height() int64 { return e.Height_ } func (e MockGoodEvidence) Address() []byte { return e.Address_ } func (e MockGoodEvidence) Hash() []byte { return []byte(fmt.Sprintf("%d-%x", e.Height_, e.Address_)) } func (e MockGoodEvidence) Verify(chainID string, pubKey crypto.PubKey) error { return nil } func (e MockGoodEvidence) Equal(ev Evidence) bool { e2 := ev.(MockGoodEvidence) return e.Height_ == e2.Height_ && bytes.Equal(e.Address_, e2.Address_) } func (e MockGoodEvidence) String() string { return fmt.Sprintf("GoodEvidence: %d/%s", e.Height_, e.Address_) } // UNSTABLE type MockBadEvidence struct { MockGoodEvidence } func (e MockBadEvidence) Verify(chainID string, pubKey crypto.PubKey) error { return fmt.Errorf("MockBadEvidence") } func (e MockBadEvidence) Equal(ev Evidence) bool { e2 := ev.(MockBadEvidence) return e.Height_ == e2.Height_ && bytes.Equal(e.Address_, e2.Address_) } func (e MockBadEvidence) String() string { return fmt.Sprintf("BadEvidence: %d/%s", e.Height_, e.Address_) } //------------------------------------------- // EvidenceList is a list of Evidence. Evidences is not a word. type EvidenceList []Evidence // Hash returns the simple merkle root hash of the EvidenceList. func (evl EvidenceList) Hash() []byte { // Recursive impl. // Copied from crypto/merkle to avoid allocations switch len(evl) { case 0: return nil case 1: return evl[0].Hash() default: left := EvidenceList(evl[:(len(evl)+1)/2]).Hash() right := EvidenceList(evl[(len(evl)+1)/2:]).Hash() return merkle.SimpleHashFromTwoHashes(left, right) } } func (evl EvidenceList) String() string { s := "" for _, e := range evl { s += fmt.Sprintf("%s\t\t", e) } return s } // Has returns true if the evidence is in the EvidenceList. func (evl EvidenceList) Has(evidence Evidence) bool { for _, ev := range evl { if ev.Equal(evidence) { return true } } return false }