adjust ValidateDecideMessage API

Author: xtaci

consensus.go

@@ -745,13 +745,14 @@ func (c *Consensus) verifyCommitMessage(m *Message) error {
 
 // ValidateDecideMessage validates a <decide> message for non-participants,
 // the consensus core must be correctly initialized to validate.
-func (c *Consensus) ValidateDecideMessage(bts []byte) error {
+// the targetState is to compare the target state enclosed in decide message
+func (c *Consensus) ValidateDecideMessage(bts []byte, targetState []byte) error {
 	signed, err := c.DecodeSignedMessage(bts)
 	if err != nil {
 		return err
 	}
 
-	return c.validateDecideMessage(signed)
+	return c.validateDecideMessage(signed, targetState)
 }
 
 // DecodeSignedMessage decodes a binary representation of signed consensus message.
@@ -766,7 +767,7 @@ func (c *Consensus) DecodeSignedMessage(bts []byte) (*SignedProto, error) {
 
 // validateDecideMessage validates a decoded <decide> message for non-participants,
 // the consensus core must be correctly initialized to validate.
-func (c *Consensus) validateDecideMessage(signed *SignedProto) error {
+func (c *Consensus) validateDecideMessage(signed *SignedProto, targetState []byte) error {
 	// check message version
 	if signed.Version != ProtocolVersion {
 		return ErrMessageVersion
@@ -778,6 +779,11 @@ func (c *Consensus) validateDecideMessage(signed *SignedProto) error {
 		return err
 	}
 
+	// compare state
+	if !bytes.Equal(m.State, targetState) {
+		return ErrMismatchedTargetState
+	}
+
 	// verify decide message
 	if m.Type == MessageType_Decide {
 		err := c.verifyDecideMessage(m, signed)

errors.go

@@ -103,4 +103,7 @@ var (
 	ErrCommitStatus          = errors.New("received <commit> message in non COMMIT state")
 	ErrCommitHeightMismatch  = errors.New("the <commit> messge has another height than expected")
 	ErrCommitRoundMismatch   = errors.New("the <commit> message is from another round")
+
+	// <decide> verification
+	ErrMismatchedTargetState = errors.New("the state in <decide> message does not match the provided target state")
 )

message_test.go

@@ -919,27 +919,27 @@ func TestVerifyDecideMessageCorrect(t *testing.T) {
 }
 
 func TestValidateDecideMessageCorrect(t *testing.T) {
-	_, sp, privateKey, proofKeys := createDecideMessage(t, 20, 10, 10, 10, 10)
+	m, sp, privateKey, proofKeys := createDecideMessage(t, 20, 10, 10, 10, 10)
 	consensus := createConsensus(t, 9, 10, proofKeys)
 
 	consensus.SetLeader(&privateKey.PublicKey)
 	bts, err := proto.Marshal(sp)
 	assert.Nil(t, err)
 
-	err = consensus.ValidateDecideMessage(bts)
+	err = consensus.ValidateDecideMessage(bts, m.State)
 	assert.Nil(t, err)
 }
 
 func TestValidateDecideMessageUnknowParticipant(t *testing.T) {
-	_, sp, privateKey, proofKeys := createDecideMessage(t, 20, 10, 10, 10, 10)
+	m, sp, privateKey, proofKeys := createDecideMessage(t, 20, 10, 10, 10, 10)
 	consensus := createConsensus(t, 9, 10, proofKeys)
 
 	consensus.SetLeader(&privateKey.PublicKey)
 	bts, err := proto.Marshal(sp)
 	assert.Nil(t, err)
 
 	consensus = createConsensus(t, 9, 10, nil)
-	err = consensus.ValidateDecideMessage(bts)
+	err = consensus.ValidateDecideMessage(bts, m.State)
 	assert.NotNil(t, err)
 }