dbft: add commit verification callback

Signed-off-by: Anna Shaleva <[email protected]>

config.go

@@ -89,6 +89,10 @@ type Config[H Hash] struct {
 	// Note that PreBlock-dependent PreCommit verification should be performed inside PreBlock.Verify
 	// callback.
 	VerifyPreCommit func(p ConsensusPayload[H]) error
+	// VerifyCommit performs external Commit verification and returns nil if it's successful.
+	// Note that Block-dependent Commit verification should be performed inside Block.Verify
+	// callback.
+	VerifyCommit func(p ConsensusPayload[H]) error
 }
 
 const defaultSecondsPerBlock = time.Second * 15
@@ -151,6 +155,8 @@ func checkConfig[H Hash](cfg *Config[H]) error {
 		return errors.New("NewRecoveryRequest is nil")
 	} else if cfg.NewRecoveryMessage == nil {
 		return errors.New("NewRecoveryMessage is nil")
+	} else if cfg.VerifyCommit == nil {
+		return errors.New("VerifyCommit is nil")
 	} else if cfg.AntiMEVExtensionEnablingHeight >= 0 {
 		if cfg.NewPreBlockFromContext == nil {
 			return errors.New("NewPreBlockFromContext is nil")
@@ -400,3 +406,10 @@ func WithVerifyPreCommit[H Hash](f func(preCommit ConsensusPayload[H]) error) fu
 		cfg.VerifyPreCommit = f
 	}
 }
+
+// WithVerifyCommit sets VerifyCommit.
+func WithVerifyCommit[H Hash](f func(commit ConsensusPayload[H]) error) func(config *Config[H]) {
+	return func(cfg *Config[H]) {
+		cfg.VerifyCommit = f
+	}
+}

dbft.go

@@ -586,6 +586,12 @@ func (d *DBFT[H]) onCommit(msg ConsensusPayload[H]) {
 	}
 	d.CommitPayloads[msg.ValidatorIndex()] = msg
 	if d.ViewNumber == msg.ViewNumber() {
+		if err := d.VerifyCommit(msg); err != nil {
+			d.CommitPayloads[msg.ValidatorIndex()] = nil
+			d.Logger.Warn("invalid Commit", zap.Uint16("from", msg.ValidatorIndex()), zap.String("error", err.Error()))
+			return
+		}
+
 		d.Logger.Info("received Commit", zap.Uint("validator", uint(msg.ValidatorIndex())))
 		d.extendTimer(4)
 		header := d.MakeHeader()

dbft_test.go

@@ -578,6 +578,14 @@ func TestDBFT_Invalid(t *testing.T) {
 	opts = append(opts, dbft.WithNewRecoveryMessage[crypto.Uint256](func() dbft.RecoveryMessage[crypto.Uint256] {
 		return nil
 	}))
+	t.Run("without VerifyCommit", func(t *testing.T) {
+		_, err := dbft.New(opts...)
+		require.Error(t, err)
+	})
+
+	opts = append(opts, dbft.WithVerifyCommit[crypto.Uint256](func(dbft.ConsensusPayload[crypto.Uint256]) error {
+		return nil
+	}))
 	t.Run("with all defaults", func(t *testing.T) {
 		d, err := dbft.New(opts...)
 		require.NoError(t, err)
@@ -1150,6 +1158,7 @@ func (s *testState) getOptions() []func(*dbft.Config[crypto.Uint256]) {
 		dbft.WithNewRecoveryMessage[crypto.Uint256](func() dbft.RecoveryMessage[crypto.Uint256] {
 			return consensus.NewRecoveryMessage(nil)
 		}),
+		dbft.WithVerifyCommit[crypto.Uint256](func(p dbft.ConsensusPayload[crypto.Uint256]) error { return nil }),
 	}
 
 	verify := s.verify

internal/consensus/consensus.go

@@ -40,6 +40,7 @@ func New(logger *zap.Logger, key dbft.PrivateKey, pub dbft.PublicKey,
 		dbft.WithGetValidators[crypto.Uint256](getValidators),
 		dbft.WithVerifyPrepareRequest[crypto.Uint256](verifyPayload),
 		dbft.WithVerifyPrepareResponse[crypto.Uint256](verifyPayload),
+		dbft.WithVerifyCommit[crypto.Uint256](verifyPayload),
 
 		dbft.WithNewBlockFromContext[crypto.Uint256](newBlockFromContext),
 		dbft.WithNewConsensusPayload[crypto.Uint256](defaultNewConsensusPayload),