types: comments; compiles; evidence test

state/execution.go

@@ -310,11 +310,8 @@ func (s *State) validateBlock(b *types.Block) error {
 	}
 
 	for _, ev := range block.Evidence.Evidence {
-		if err := ev.VoteA.Verify(s.ChainID, ev.PubKey); err != nil {
-			return types.ErrEvidenceInvalid(ev, err)
-		}
-		if err := ev.VoteB.Verify(s.ChainID, ev.PubKey); err != nil {
-			return types.ErrEvidenceInvalid(ev, err)
+		if err := ev.Verify(s.ChainID); err != nil {
+			return types.NewEvidenceInvalidErr(ev, err)
 		}
 	}
 

types/evidence.go

@@ -7,36 +7,44 @@ import (
 	"github.com/tendermint/go-crypto"
 )
 
+// ErrEvidenceInvalid wraps a piece of evidence and the error denoting how or why it is invalid.
 type ErrEvidenceInvalid struct {
-	Evidence Evidence
-	Error    error
+	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.Error, err.Evidence)
+	return fmt.Sprintf("Invalid evidence: %v. Evidence: %v", err.ErrorValue, err.Evidence)
 }
 
 // Evidence represents any provable malicious activity by a validator
 type Evidence interface {
-	Verify() error
+	Verify(chainID string) error
 	Address() []byte
 }
 
 //-------------------------------------------
 
+// DuplicateVoteEvidence contains evidence a validator signed two conflicting votes.
 type DuplicateVoteEvidence struct {
 	PubKey crypto.PubKey
 	VoteA  *Vote
 	VoteB  *Vote
 }
 
-// Address returns the address of the validator
+// Address returns the address of the validator.
 func (dve *DuplicateVoteEvidence) Address() []byte {
 	return dve.PubKey.Address()
 }
 
-// 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 {
+// 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) error {
 	// H/R/S must be the same
 	if dve.VoteA.Height != dve.VoteB.Height ||
 		dve.VoteA.Round != dve.VoteB.Round ||
@@ -59,10 +67,10 @@ func (dve *DuplicateVoteEvidence) Verify() error {
 	}
 
 	// Signatures must be valid
-	if !dve.PubKey.Verify(SignBytes(chainID, dve.VoteA), dve.VoteA.Signature) {
+	if !dve.PubKey.VerifyBytes(SignBytes(chainID, dve.VoteA), dve.VoteA.Signature) {
 		return ErrVoteInvalidSignature
 	}
-	if !dve.PubKey.Verify(SignBytes(chainID, dve.VoteB), dve.VoteB.Signature) {
+	if !dve.PubKey.VerifyBytes(SignBytes(chainID, dve.VoteB), dve.VoteB.Signature) {
 		return ErrVoteInvalidSignature
 	}
 

types/evidence_test.go

@@ -0,0 +1,82 @@
+package types
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type voteData struct {
+	vote1 *Vote
+	vote2 *Vote
+	valid bool
+}
+
+func makeVote(val *PrivValidator, chainID string, valIndex, height, round, step int, blockID BlockID) *Vote {
+	v := &Vote{
+		ValidatorAddress: val.PubKey.Address(),
+		ValidatorIndex:   valIndex,
+		Height:           height,
+		Round:            round,
+		Type:             byte(step),
+		BlockID:          blockID,
+	}
+	sig := val.PrivKey.Sign(SignBytes(chainID, v))
+	v.Signature = sig
+	return v
+
+}
+
+func makeBlockID(hash string, partSetSize int, partSetHash string) BlockID {
+	return BlockID{
+		Hash: []byte(hash),
+		PartsHeader: PartSetHeader{
+			Total: partSetSize,
+			Hash:  []byte(partSetHash),
+		},
+	}
+
+}
+
+func TestEvidence(t *testing.T) {
+	val := GenPrivValidator()
+	val2 := GenPrivValidator()
+	blockID := makeBlockID("blockhash", 1000, "partshash")
+	blockID2 := makeBlockID("blockhash2", 1000, "partshash")
+	blockID3 := makeBlockID("blockhash", 10000, "partshash")
+	blockID4 := makeBlockID("blockhash", 10000, "partshash2")
+
+	chainID := "mychain"
+
+	vote1 := makeVote(val, chainID, 0, 10, 2, 1, blockID)
+	badVote := makeVote(val, chainID, 0, 10, 2, 1, blockID)
+	badVote.Signature = val2.PrivKey.Sign(SignBytes(chainID, badVote))
+
+	cases := []voteData{
+		{vote1, makeVote(val, chainID, 0, 10, 2, 1, blockID2), true}, // different block ids
+		{vote1, makeVote(val, chainID, 0, 10, 2, 1, blockID3), true},
+		{vote1, makeVote(val, chainID, 0, 10, 2, 1, blockID4), true},
+		{vote1, makeVote(val, chainID, 0, 10, 2, 1, blockID), false},     // wrong block id
+		{vote1, makeVote(val, "mychain2", 0, 10, 2, 1, blockID2), false}, // wrong chain id
+		{vote1, makeVote(val, chainID, 1, 10, 2, 1, blockID2), false},    // wrong val index
+		{vote1, makeVote(val, chainID, 0, 11, 2, 1, blockID2), false},    // wrong height
+		{vote1, makeVote(val, chainID, 0, 10, 3, 1, blockID2), false},    // wrong round
+		{vote1, makeVote(val, chainID, 0, 10, 2, 2, blockID2), false},    // wrong step
+		{vote1, makeVote(val2, chainID, 0, 10, 2, 1, blockID), false},    // wrong validator
+		{vote1, badVote, false},                                          // signed by wrong key
+	}
+
+	for _, c := range cases {
+		ev := &DuplicateVoteEvidence{
+			PubKey: val.PubKey,
+			VoteA:  c.vote1,
+			VoteB:  c.vote2,
+		}
+		if c.valid {
+			assert.Nil(t, ev.Verify(chainID), "evidence should be valid")
+		} else {
+			assert.NotNil(t, ev.Verify(chainID), "evidence should be invalid")
+		}
+	}
+
+}

types/vote.go

@@ -1,6 +1,7 @@
 package types
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -103,7 +104,7 @@ func (vote *Vote) String() string {
 }
 
 func (vote *Vote) Verify(chainID string, pubKey crypto.PubKey) error {
-	if !bytes.Equal(pubKey.Address(), v.ValidatorAddress) {
+	if !bytes.Equal(pubKey.Address(), vote.ValidatorAddress) {
 		return ErrVoteInvalidValidatorAddress
 	}