track evidence, include in block

consensus/state.go

@@ -863,7 +863,9 @@ func (cs *ConsensusState) createProposalBlock() (block *types.Block, blockParts
 
 	// Mempool validated transactions
 	txs := cs.mempool.Reap(cs.config.MaxBlockSizeTxs)
-	return cs.state.MakeBlock(cs.Height, txs, commit)
+	block, parts := cs.state.MakeBlock(cs.Height, txs, commit)
+	block.AddEvidence(cs.Evidence)
+	return block, parts
 }
 
 // Enter: `timeoutPropose` after entering Propose.
@@ -1231,6 +1233,10 @@ func (cs *ConsensusState) finalizeCommit(height int64) {
 
 	fail.Fail() // XXX
 
+	// TODO: remove included evidence
+	// and persist remaining evidence
+	// ... is this the right spot? need to ensure we never lose evidence
+
 	// NewHeightStep!
 	cs.updateToState(stateCopy)
 
@@ -1327,15 +1333,14 @@ func (cs *ConsensusState) tryAddVote(vote *types.Vote, peerKey string) error {
 		// If it's otherwise invalid, punish peer.
 		if err == ErrVoteHeightMismatch {
 			return err
-		} else if _, ok := err.(*types.ErrVoteConflictingVotes); ok {
+		} else if voteErr, ok := err.(*types.ErrVoteConflictingVotes); ok {
 			if bytes.Equal(vote.ValidatorAddress, cs.privValidator.GetAddress()) {
 				cs.Logger.Error("Found conflicting vote from ourselves. Did you unsafe_reset a validator?", "height", vote.Height, "round", vote.Round, "type", vote.Type)
 				return err
 			}
-			cs.Logger.Error("Found conflicting vote. Publish evidence (TODO)", "height", vote.Height, "round", vote.Round, "type", vote.Type, "valAddr", vote.ValidatorAddress, "valIndex", vote.ValidatorIndex)
-
-			// TODO: track evidence for inclusion in a block
+			cs.Logger.Error("Found conflicting vote. Recording evidence in the RoundState", "height", vote.Height, "round", vote.Round, "type", vote.Type, "valAddr", vote.ValidatorAddress, "valIndex", vote.ValidatorIndex)
 
+			cs.Evidence = append(cs.Evidence, &types.DuplicateVoteEvidence{voteErr.VoteA, voteErr.VoteB})
 			return err
 		} else {
 			// Probably an invalid signature / Bad peer.

state/execution.go

@@ -309,6 +309,8 @@ func (s *State) validateBlock(b *types.Block) error {
 		}
 	}
 
+	// TODO: Validate evidence
+
 	return nil
 }
 

types/block.go

@@ -19,7 +19,8 @@ import (
 type Block struct {
 	*Header    `json:"header"`
 	*Data      `json:"data"`
-	LastCommit *Commit `json:"last_commit"`
+	Evidence   EvidenceData `json:"evidence"`
+	LastCommit *Commit      `json:"last_commit"`
 }
 
 // MakeBlock returns a new block with an empty header, except what can be computed from itself.
@@ -40,6 +41,11 @@ func MakeBlock(height int64, txs []Tx, commit *Commit) *Block {
 	return block
 }
 
+// AddEvidence appends the given evidence to the block
+func (b *Block) AddEvidence(evidence []Evidence) {
+	b.Evidence.Evidence = append(b.Evidence.Evidence, evidence...)
+}
+
 // ValidateBasic performs basic validation that doesn't involve state data.
 // It checks the internal consistency of the block.
 func (b *Block) ValidateBasic() error {
@@ -58,6 +64,9 @@ func (b *Block) ValidateBasic() error {
 	if !bytes.Equal(b.DataHash, b.Data.Hash()) {
 		return fmt.Errorf("Wrong Block.Header.DataHash.  Expected %v, got %v", b.DataHash, b.Data.Hash())
 	}
+	if !bytes.Equal(b.EvidenceHash, b.Evidence.Hash()) {
+		return errors.New(cmn.Fmt("Wrong Block.Header.EvidenceHash.  Expected %v, got %v", b.EvidenceHash, b.Evidence.Hash()))
+	}
 	return nil
 }
 
@@ -69,6 +78,9 @@ func (b *Block) FillHeader() {
 	if b.DataHash == nil {
 		b.DataHash = b.Data.Hash()
 	}
+	if b.EvidenceHash == nil {
+		b.EvidenceHash = b.Evidence.Hash()
+	}
 }
 
 // Hash computes and returns the block hash.
@@ -114,9 +126,11 @@ func (b *Block) StringIndented(indent string) string {
 %s  %v
 %s  %v
 %s  %v
+%s  %v
 %s}#%v`,
 		indent, b.Header.StringIndented(indent+"  "),
 		indent, b.Data.StringIndented(indent+"  "),
+		indent, b.Evidence.StringIndented(indent+"  "),
 		indent, b.LastCommit.StringIndented(indent+"  "),
 		indent, b.Hash())
 }
@@ -134,6 +148,7 @@ func (b *Block) StringShort() string {
 
 // Header defines the structure of a Tendermint block header
 // TODO: limit header size
+// NOTE: changes to the Header should be duplicated in the abci Header
 type Header struct {
 	// basic block info
 	ChainID string    `json:"chain_id"`
@@ -154,6 +169,9 @@ type Header struct {
 	ConsensusHash   data.Bytes `json:"consensus_hash"`    // consensus params for current block
 	AppHash         data.Bytes `json:"app_hash"`          // state after txs from the previous block
 	LastResultsHash data.Bytes `json:"last_results_hash"` // root hash of all results from the txs from the previous block
+
+	// consensus info
+	EvidenceHash data.Bytes `json:"evidence_hash"` // evidence included in the block
 }
 
 // Hash returns the hash of the header.
@@ -175,6 +193,7 @@ func (h *Header) Hash() data.Bytes {
 		"App":         h.AppHash,
 		"Consensus":   h.ConsensusHash,
 		"Results":     h.LastResultsHash,
+		"Evidence":    h.EvidenceHash,
 	})
 }
 
@@ -196,6 +215,7 @@ func (h *Header) StringIndented(indent string) string {
 %s  App:            %v
 %s  Conensus:       %v
 %s  Results:        %v
+%s  Evidence:       %v
 %s}#%v`,
 		indent, h.ChainID,
 		indent, h.Height,
@@ -209,6 +229,7 @@ func (h *Header) StringIndented(indent string) string {
 		indent, h.AppHash,
 		indent, h.ConsensusHash,
 		indent, h.LastResultsHash,
+		indent, h.EvidenceHash,
 		indent, h.Hash())
 }
 
@@ -413,6 +434,33 @@ func (data *Data) StringIndented(indent string) string {
 		indent, data.hash)
 }
 
+//-----------------------------------------------------------------------------
+
+// EvidenceData contains any evidence of malicious wrong-doing by validators
+type EvidenceData struct {
+	Evidence []Evidence `json:"evidence"`
+
+	// Volatile
+	hash data.Bytes
+}
+
+// Hash returns the hash of the data
+func (data *EvidenceData) Hash() data.Bytes {
+	if data.hash == nil {
+		// TODO
+	}
+	return data.hash
+}
+
+// StringIndented returns a string representation of the transactions
+func (data *EvidenceData) StringIndented(indent string) string {
+	if data == nil {
+		return "nil-Data"
+	}
+	// TODO
+	return ""
+}
+
 //--------------------------------------------------------------------------------
 
 // BlockID defines the unique ID of a block as its Hash and its PartSetHeader

types/evidence.go

@@ -0,0 +1,52 @@
+package types
+
+import (
+	"bytes"
+	"fmt"
+)
+
+// Evidence represents any provable malicious activity by a validator
+type Evidence interface {
+	Verify() error
+	Address() []byte
+}
+
+//-------------------------------------------
+
+type DuplicateVoteEvidence struct {
+	VoteA *Vote
+	VoteB *Vote
+}
+
+// Address returns the address of the validator
+func (dve *DuplicateVoteEvidence) Address() []byte {
+	return dve.VoteA.ValidatorAddress
+}
+
+// Verify returns an error if the two votes aren't from the same validator, for the same H/R/S, but for different blocks
+func (dve *DuplicateVoteEvidence) Verify() 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 and Index 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)
+	}
+	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)
+	}
+
+	// Signatures must be valid
+	// TODO
+
+	return nil
+}