abci++: add consensus parameter to control vote extension require height

internal/blocksync/reactor.go

@@ -557,7 +557,10 @@ func (r *Reactor) poolRoutine(ctx context.Context, stateSynced bool, blockSyncCh
 				// validate the block before we persist it
 				err = r.blockExec.ValidateBlock(ctx, state, first)
 			}
-
+			if err == nil && state.ConsensusParams.Vote.RequireExtensions(extCommit.Height) {
+				// if vote extensions were required at this height, ensure they exist.
+				err = extCommit.EnsureExtensions()
+			}
 			// If either of the checks failed we log the error and request for a new block
 			// at that height
 			if err != nil {

internal/consensus/msgs.go

@@ -222,11 +222,7 @@ func (*VoteMessage) TypeTag() string { return "tendermint/Vote" }
 
 // ValidateBasic checks whether the vote within the message is well-formed.
 func (m *VoteMessage) ValidateBasic() error {
-	// Here we validate votes with vote extensions, since we require vote
-	// extensions to be sent in precommit messages during consensus. Prevote
-	// messages should never have vote extensions, and this is also validated
-	// here.
-	return m.Vote.ValidateWithExtension()
+	return m.Vote.ValidateBasic()
 }
 
 // String returns a string representation.

internal/consensus/reactor_test.go

@@ -32,6 +32,7 @@ import (
 	"github.com/tendermint/tendermint/internal/test/factory"
 	"github.com/tendermint/tendermint/libs/log"
 	tmcons "github.com/tendermint/tendermint/proto/tendermint/consensus"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -600,6 +601,106 @@ func TestReactorCreatesBlockWhenEmptyBlocksFalse(t *testing.T) {
 	wg.Wait()
 }
 
+func TestSwitchToConsensusVoteExtensions(t *testing.T) {
+	for _, testCase := range []struct {
+		name                  string
+		storedHeight          int64
+		initialRequiredHeight int64
+		includeExtensions     bool
+		shouldPanic           bool
+	}{
+		{
+			name:                  "no vote extensions but not required",
+			initialRequiredHeight: 0,
+			storedHeight:          2,
+			includeExtensions:     false,
+			shouldPanic:           false,
+		},
+		{
+			name:                  "no vote extensions but required this height",
+			initialRequiredHeight: 2,
+			storedHeight:          2,
+			includeExtensions:     false,
+			shouldPanic:           true,
+		},
+		{
+			name:                  "no vote extensions and required in future",
+			initialRequiredHeight: 3,
+			storedHeight:          2,
+			includeExtensions:     false,
+			shouldPanic:           false,
+		},
+		{
+			name:                  "no vote extensions and required previous height",
+			initialRequiredHeight: 1,
+			storedHeight:          2,
+			includeExtensions:     false,
+			shouldPanic:           true,
+		},
+		{
+			name:                  "vote extensions and required previous height",
+			initialRequiredHeight: 1,
+			storedHeight:          2,
+			includeExtensions:     true,
+			shouldPanic:           false,
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+			defer cancel()
+			cs, vs := makeState(ctx, t, makeStateArgs{validators: 1})
+			validator := vs[0]
+			validator.Height = testCase.storedHeight
+
+			cs.state.LastBlockHeight = testCase.storedHeight
+			cs.state.LastValidators = cs.state.Validators.Copy()
+			cs.state.ConsensusParams.Vote.ExtensionRequireHeight = testCase.initialRequiredHeight
+
+			propBlock, err := cs.createProposalBlock(ctx)
+			require.NoError(t, err)
+
+			// Consensus is preparing to do the next height after the stored height.
+			cs.Height = testCase.storedHeight + 1
+			propBlock.Height = testCase.storedHeight
+			blockParts, err := propBlock.MakePartSet(types.BlockPartSizeBytes)
+			require.NoError(t, err)
+
+			voteSet := types.NewVoteSet(cs.state.ChainID, testCase.storedHeight, 0, tmproto.PrecommitType, cs.state.Validators, testCase.includeExtensions)
+			signedVote := signVote(ctx, t, validator, tmproto.PrecommitType, cs.state.ChainID, types.BlockID{
+				Hash:          propBlock.Hash(),
+				PartSetHeader: blockParts.Header(),
+			})
+
+			if !testCase.includeExtensions {
+				signedVote.Extension = nil
+				signedVote.ExtensionSignature = nil
+			}
+
+			added, err := voteSet.AddVote(signedVote)
+			require.NoError(t, err)
+			require.True(t, added)
+			cs.blockStore.SaveBlock(propBlock, blockParts, voteSet.MakeExtendedCommit())
+			reactor := NewReactor(
+				log.NewNopLogger(),
+				cs,
+				nil,
+				nil,
+				cs.eventBus,
+				true,
+				NopMetrics(),
+			)
+
+			if testCase.shouldPanic {
+				assert.Panics(t, func() {
+					reactor.SwitchToConsensus(ctx, cs.state, false)
+				})
+			} else {
+				reactor.SwitchToConsensus(ctx, cs.state, false)
+			}
+		})
+	}
+}
+
 func TestReactorRecordsVotesAndBlockParts(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
 	defer cancel()

internal/consensus/state.go

@@ -692,23 +692,53 @@ func (cs *State) sendInternalMessage(ctx context.Context, mi msgInfo) {
 	}
 }
 
-// Reconstruct LastCommit from SeenCommit, which we saved along with the block,
-// (which happens even before saving the state)
+// Reconstruct LastCommit from either SeenCommit or the ExtendedCommit. SeenCommit
+// and ExtendedCommit are saved along with the block. If VoteExtensions are required
+// the method will panic on an absent ExtendedCommit or an ExtendedCommit without
+// extension data.
 func (cs *State) reconstructLastCommit(state sm.State) {
-	extCommit := cs.blockStore.LoadBlockExtendedCommit(state.LastBlockHeight)
-	if extCommit == nil {
-		panic(fmt.Sprintf(
-			"failed to reconstruct last commit; commit for height %v not found",
-			state.LastBlockHeight,
-		))
+	requireExtensions := cs.state.ConsensusParams.Vote.RequireExtensions(state.LastBlockHeight)
+	votes, err := cs.votesFromExtendedCommit(state, requireExtensions)
+	if err == nil {
+		cs.LastCommit = votes
+		return
+	}
+	if requireExtensions {
+		panic(fmt.Sprintf("failed to reconstruct last commit; %s", err))
+	}
+	votes, err = cs.votesFromSeenCommit(state)
+	if err != nil {
+		panic(fmt.Sprintf("failed to reconstruct last commit; %s", err))
+	}
+	cs.LastCommit = votes
+}
+
+func (cs *State) votesFromExtendedCommit(state sm.State, requireExtensions bool) (*types.VoteSet, error) {
+	ec := cs.blockStore.LoadBlockExtendedCommit(state.LastBlockHeight)
+	if ec == nil {
+		return nil, fmt.Errorf("commit for height %v not found", state.LastBlockHeight)
+	}
+	vs := ec.ToVoteSet(state.ChainID, state.LastValidators, requireExtensions)
+	if !vs.HasTwoThirdsMajority() {
+		return nil, errors.New("extended commit does not have +2/3 majority")
+	}
+	return vs, nil
+}
+
+func (cs *State) votesFromSeenCommit(state sm.State) (*types.VoteSet, error) {
+	commit := cs.blockStore.LoadSeenCommit()
+	if commit == nil || commit.Height != state.LastBlockHeight {
+		commit = cs.blockStore.LoadBlockCommit(state.LastBlockHeight)
+	}
+	if commit == nil {
+		return nil, fmt.Errorf("commit for height %v not found", state.LastBlockHeight)
 	}
 
-	lastPrecommits := extCommit.ToVoteSet(state.ChainID, state.LastValidators)
-	if !lastPrecommits.HasTwoThirdsMajority() {
-		panic("failed to reconstruct last commit; does not have +2/3 maj")
+	vs := commit.ToVoteSet(state.ChainID, state.LastValidators)
+	if !vs.HasTwoThirdsMajority() {
+		return nil, errors.New("commit does not have +2/3 majority")
 	}
-
-	cs.LastCommit = lastPrecommits
+	return vs, nil
 }
 
 // Updates State and increments height to match that of state.
@@ -810,7 +840,8 @@ func (cs *State) updateToState(state sm.State) {
 	cs.ValidRound = -1
 	cs.ValidBlock = nil
 	cs.ValidBlockParts = nil
-	cs.Votes = cstypes.NewHeightVoteSet(state.ChainID, height, validators)
+	requireExtensions := state.ConsensusParams.Vote.RequireExtensions(height)
+	cs.Votes = cstypes.NewHeightVoteSet(state.ChainID, height, validators, requireExtensions)
 	cs.CommitRound = -1
 	cs.LastValidators = state.LastValidators
 	cs.TriggeredTimeoutPrecommit = false
@@ -2337,13 +2368,37 @@ func (cs *State) addVote(
 		return
 	}
 
+	var addr []byte
+	if cs.privValidatorPubKey != nil {
+		addr = cs.privValidatorPubKey.Address()
+	}
 	// Verify VoteExtension if precommit and not nil
 	// https://github.com/tendermint/tendermint/issues/8487
-	if vote.Type == tmproto.PrecommitType && !vote.BlockID.IsNil() {
-		err := cs.blockExec.VerifyVoteExtension(ctx, vote)
-		cs.metrics.MarkVoteExtensionReceived(err == nil)
-		if err != nil {
-			return false, err
+	if vote.Type == tmproto.PrecommitType && !vote.BlockID.IsNil() &&
+		!bytes.Equal(vote.ValidatorAddress, addr) {
+		// The core fields of the vote message were already validated in the
+		// consensus reactor when the vote was received.
+		// Here, we valdiate that the vote extension was included in the vote
+		// message.
+		// Chains that are not configured to require vote extensions
+		// will consider the vote valid even if the extension is absent.
+		// VerifyVoteExtension will not be called in this case if the extension
+		// is absent.
+		err := vote.EnsureExtension()
+		if err == nil {
+			_, val := cs.state.Validators.GetByIndex(vote.ValidatorIndex)
+			err = vote.VerifyExtension(cs.state.ChainID, val.PubKey)
+		}
+		if err == nil {
+			err := cs.blockExec.VerifyVoteExtension(ctx, vote)
+			cs.metrics.MarkVoteExtensionReceived(err == nil)
+		} else {
+			if !errors.Is(err, types.ErrVoteExtensionAbsent) {
+				return false, err
+			}
+			if cs.state.ConsensusParams.Vote.RequireExtensions(cs.Height) {
+				return false, err
+			}
 		}
 	}
 

internal/consensus/state_test.go

@@ -2076,19 +2076,13 @@ func TestExtendVoteCalled(t *testing.T) {
 		Hash:   blockID.Hash,
 	})
 
-	m.AssertCalled(t, "VerifyVoteExtension", ctx, &abci.RequestVerifyVoteExtension{
-		Hash:             blockID.Hash,
-		ValidatorAddress: addr,
-		Height:           height,
-		VoteExtension:    []byte("extension"),
-	})
 	signAddVotes(ctx, t, cs1, tmproto.PrecommitType, config.ChainID(), blockID, vss[1:]...)
 	ensureNewRound(t, newRoundCh, height+1, 0)
 	m.AssertExpectations(t)
 
 	// Only 3 of the vote extensions are seen, as consensus proceeds as soon as the +2/3 threshold
 	// is observed by the consensus engine.
-	for _, pv := range vss[:3] {
+	for _, pv := range vss[1:3] {
 		pv, err := pv.GetPubKey(ctx)
 		require.NoError(t, err)
 		addr := pv.Address()
@@ -2148,13 +2142,6 @@ func TestVerifyVoteExtensionNotCalledOnAbsentPrecommit(t *testing.T) {
 		Hash:   blockID.Hash,
 	})
 
-	m.AssertCalled(t, "VerifyVoteExtension", mock.Anything, &abci.RequestVerifyVoteExtension{
-		Hash:             blockID.Hash,
-		ValidatorAddress: addr,
-		Height:           height,
-		VoteExtension:    []byte("extension"),
-	})
-
 	m.On("Commit", mock.Anything).Return(&abci.ResponseCommit{}, nil).Maybe()
 	signAddVotes(ctx, t, cs1, tmproto.PrecommitType, config.ChainID(), blockID, vss[2:]...)
 	ensureNewRound(t, newRoundCh, height+1, 0)
@@ -2266,6 +2253,118 @@ func TestPrepareProposalReceivesVoteExtensions(t *testing.T) {
 	}
 }
 
+// TestVoteExtensionRequiredHeight tests that 'ExtensionRequireHeight' correctly
+// enforces that vote extensions be present in consensus for heights greater than
+// or equal to the configured value.
+func TestVoteExtensionRequiredHeight(t *testing.T) {
+	for _, testCase := range []struct {
+		name                  string
+		initialRequiredHeight int64
+		hasExtension          bool
+		expectSuccessfulRound bool
+	}{
+		{
+			name:                  "extension present but not required",
+			hasExtension:          true,
+			initialRequiredHeight: 0,
+			expectSuccessfulRound: true,
+		},
+		{
+			name:                  "extension absent but not required",
+			hasExtension:          false,
+			initialRequiredHeight: 0,
+			expectSuccessfulRound: true,
+		},
+		{
+			name:                  "extension present and required",
+			hasExtension:          true,
+			initialRequiredHeight: 1,
+			expectSuccessfulRound: true,
+		},
+		{
+			name:                  "extension absent but required",
+			hasExtension:          false,
+			initialRequiredHeight: 1,
+			expectSuccessfulRound: false,
+		},
+		{
+			name:                  "extension absent but required in future height",
+			hasExtension:          false,
+			initialRequiredHeight: 2,
+			expectSuccessfulRound: true,
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			config := configSetup(t)
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+
+			numValidators := 3
+			m := abcimocks.NewApplication(t)
+			m.On("ProcessProposal", mock.Anything, mock.Anything).Return(&abci.ResponseProcessProposal{
+				Status: abci.ResponseProcessProposal_ACCEPT,
+			}, nil)
+			m.On("PrepareProposal", mock.Anything, mock.Anything).Return(&abci.ResponsePrepareProposal{}, nil)
+			m.On("ExtendVote", mock.Anything, mock.Anything).Return(&abci.ResponseExtendVote{}, nil)
+			if testCase.hasExtension {
+				m.On("VerifyVoteExtension", mock.Anything, mock.Anything).Return(&abci.ResponseVerifyVoteExtension{
+					Status: abci.ResponseVerifyVoteExtension_ACCEPT,
+				}, nil).Times(numValidators - 1)
+			}
+			m.On("FinalizeBlock", mock.Anything, mock.Anything).Return(&abci.ResponseFinalizeBlock{}, nil).Maybe()
+			m.On("Commit", mock.Anything).Return(&abci.ResponseCommit{}, nil).Maybe()
+			cs1, vss := makeState(ctx, t, makeStateArgs{config: config, application: m, validators: numValidators})
+			cs1.state.ConsensusParams.Vote.ExtensionRequireHeight = testCase.initialRequiredHeight
+			height, round := cs1.Height, cs1.Round
+
+			timeoutCh := subscribe(ctx, t, cs1.eventBus, types.EventQueryTimeoutPropose)
+			proposalCh := subscribe(ctx, t, cs1.eventBus, types.EventQueryCompleteProposal)
+			newRoundCh := subscribe(ctx, t, cs1.eventBus, types.EventQueryNewRound)
+			pv1, err := cs1.privValidator.GetPubKey(ctx)
+			require.NoError(t, err)
+			addr := pv1.Address()
+			voteCh := subscribeToVoter(ctx, t, cs1, addr)
+
+			startTestRound(ctx, cs1, cs1.Height, round)
+			ensureNewRound(t, newRoundCh, height, round)
+			ensureNewProposal(t, proposalCh, height, round)
+			rs := cs1.GetRoundState()
+
+			blockID := types.BlockID{
+				Hash:          rs.ProposalBlock.Hash(),
+				PartSetHeader: rs.ProposalBlockParts.Header(),
+			}
+
+			// sign all of the votes
+			signAddVotes(ctx, t, cs1, tmproto.PrevoteType, config.ChainID(), blockID, vss[1:]...)
+			ensurePrevoteMatch(t, voteCh, height, round, rs.ProposalBlock.Hash())
+
+			var ext []byte
+			if testCase.hasExtension {
+				ext = []byte("extension")
+			}
+
+			for _, vs := range vss[1:] {
+				vote, err := vs.signVote(ctx, tmproto.PrecommitType, config.ChainID(), blockID, ext)
+				if !testCase.hasExtension {
+					vote.ExtensionSignature = nil
+				}
+				require.NoError(t, err)
+				addVotes(cs1, vote)
+			}
+			if testCase.expectSuccessfulRound {
+				ensurePrecommit(t, voteCh, height, round)
+				height++
+				ensureNewRound(t, newRoundCh, height, round)
+			} else {
+				ensureNoNewTimeout(t, timeoutCh, cs1.state.ConsensusParams.Timeout.VoteTimeout(round).Nanoseconds())
+			}
+
+			m.AssertExpectations(t)
+		})
+	}
+}
+
 // 4 vals, 3 Nil Precommits at P0
 // What we want:
 // P0 waits for timeoutPrecommit before starting next round

internal/consensus/types/height_vote_set.go

@@ -38,9 +38,10 @@ We let each peer provide us with up to 2 unexpected "catchup" rounds.
 One for their LastCommit round, and another for the official commit round.
 */
 type HeightVoteSet struct {
-	chainID string
-	height  int64
-	valSet  *types.ValidatorSet
+	chainID           string
+	height            int64
+	valSet            *types.ValidatorSet
+	requireExtensions bool
 
 	mtx               sync.Mutex
 	round             int32                    // max tracked round
@@ -48,9 +49,10 @@ type HeightVoteSet struct {
 	peerCatchupRounds map[types.NodeID][]int32 // keys: peer.ID; values: at most 2 rounds
 }
 
-func NewHeightVoteSet(chainID string, height int64, valSet *types.ValidatorSet) *HeightVoteSet {
+func NewHeightVoteSet(chainID string, height int64, valSet *types.ValidatorSet, requireExtensions bool) *HeightVoteSet {
 	hvs := &HeightVoteSet{
-		chainID: chainID,
+		chainID:           chainID,
+		requireExtensions: requireExtensions,
 	}
 	hvs.Reset(height, valSet)
 	return hvs
@@ -107,8 +109,8 @@ func (hvs *HeightVoteSet) addRound(round int32) {
 		panic("addRound() for an existing round")
 	}
 	// log.Debug("addRound(round)", "round", round)
-	prevotes := types.NewVoteSet(hvs.chainID, hvs.height, round, tmproto.PrevoteType, hvs.valSet)
-	precommits := types.NewVoteSet(hvs.chainID, hvs.height, round, tmproto.PrecommitType, hvs.valSet)
+	prevotes := types.NewVoteSet(hvs.chainID, hvs.height, round, tmproto.PrevoteType, hvs.valSet, hvs.requireExtensions)
+	precommits := types.NewVoteSet(hvs.chainID, hvs.height, round, tmproto.PrecommitType, hvs.valSet, hvs.requireExtensions)
 	hvs.roundVoteSets[round] = RoundVoteSet{
 		Prevotes:   prevotes,
 		Precommits: precommits,

internal/consensus/types/height_vote_set_test.go

@@ -27,7 +27,7 @@ func TestPeerCatchupRounds(t *testing.T) {
 	valSet, privVals := factory.ValidatorSet(ctx, t, 10, 1)
 
 	chainID := cfg.ChainID()
-	hvs := NewHeightVoteSet(chainID, 1, valSet)
+	hvs := NewHeightVoteSet(chainID, 1, valSet, false)
 
 	vote999_0 := makeVoteHR(ctx, t, 1, 0, 999, privVals, chainID)
 	added, err := hvs.AddVote(vote999_0, "peer1")

internal/evidence/verify_test.go

@@ -233,7 +233,7 @@ func TestVerifyLightClientAttack_Equivocation(t *testing.T) {
 	// we are simulating a duplicate vote attack where all the validators in the conflictingVals set
 	// except the last validator vote twice
 	blockID := factory.MakeBlockIDWithHash(conflictingHeader.Hash())
-	voteSet := types.NewVoteSet(evidenceChainID, 10, 1, tmproto.SignedMsgType(2), conflictingVals)
+	voteSet := types.NewVoteSet(evidenceChainID, 10, 1, tmproto.SignedMsgType(2), conflictingVals, false)
 	extCommit, err := factory.MakeExtendedCommit(ctx, blockID, 10, 1, voteSet, conflictingPrivVals[:4], defaultEvidenceTime)
 	require.NoError(t, err)
 	commit := extCommit.StripExtensions()
@@ -253,7 +253,7 @@ func TestVerifyLightClientAttack_Equivocation(t *testing.T) {
 	}
 
 	trustedBlockID := makeBlockID(trustedHeader.Hash(), 1000, []byte("partshash"))
-	trustedVoteSet := types.NewVoteSet(evidenceChainID, 10, 1, tmproto.SignedMsgType(2), conflictingVals)
+	trustedVoteSet := types.NewVoteSet(evidenceChainID, 10, 1, tmproto.SignedMsgType(2), conflictingVals, false)
 	trustedExtCommit, err := factory.MakeExtendedCommit(ctx, trustedBlockID, 10, 1,
 		trustedVoteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
@@ -336,7 +336,7 @@ func TestVerifyLightClientAttack_Amnesia(t *testing.T) {
 	// we are simulating an amnesia attack where all the validators in the conflictingVals set
 	// except the last validator vote twice. However this time the commits are of different rounds.
 	blockID := makeBlockID(conflictingHeader.Hash(), 1000, []byte("partshash"))
-	voteSet := types.NewVoteSet(evidenceChainID, height, 0, tmproto.SignedMsgType(2), conflictingVals)
+	voteSet := types.NewVoteSet(evidenceChainID, height, 0, tmproto.SignedMsgType(2), conflictingVals, false)
 	extCommit, err := factory.MakeExtendedCommit(ctx, blockID, height, 0, voteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
 	commit := extCommit.StripExtensions()
@@ -356,7 +356,7 @@ func TestVerifyLightClientAttack_Amnesia(t *testing.T) {
 	}
 
 	trustedBlockID := makeBlockID(trustedHeader.Hash(), 1000, []byte("partshash"))
-	trustedVoteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), conflictingVals)
+	trustedVoteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), conflictingVals, false)
 	trustedExtCommit, err := factory.MakeExtendedCommit(ctx, trustedBlockID, height, 1,
 		trustedVoteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
@@ -553,7 +553,7 @@ func makeLunaticEvidence(
 	})
 
 	blockID := factory.MakeBlockIDWithHash(conflictingHeader.Hash())
-	voteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), conflictingVals)
+	voteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), conflictingVals, false)
 	extCommit, err := factory.MakeExtendedCommit(ctx, blockID, height, 1, voteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
 	commit := extCommit.StripExtensions()
@@ -582,7 +582,7 @@ func makeLunaticEvidence(
 	}
 	trustedBlockID := factory.MakeBlockIDWithHash(trustedHeader.Hash())
 	trustedVals, privVals := factory.ValidatorSet(ctx, t, totalVals, defaultVotingPower)
-	trustedVoteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), trustedVals)
+	trustedVoteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), trustedVals, false)
 	trustedExtCommit, err := factory.MakeExtendedCommit(ctx, trustedBlockID, height, 1, trustedVoteSet, privVals, defaultEvidenceTime)
 	require.NoError(t, err)
 	trustedCommit := trustedExtCommit.StripExtensions()

internal/state/execution.go

@@ -3,6 +3,7 @@ package state
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"time"
 
@@ -102,13 +103,12 @@ func (blockExec *BlockExecutor) CreateProposalBlock(
 	txs := blockExec.mempool.ReapMaxBytesMaxGas(maxDataBytes, maxGas)
 	commit := lastExtCommit.StripExtensions()
 	block := state.MakeBlock(height, txs, commit, evidence, proposerAddr)
-
 	rpp, err := blockExec.appClient.PrepareProposal(
 		ctx,
 		&abci.RequestPrepareProposal{
 			MaxTxBytes:          maxDataBytes,
 			Txs:                 block.Txs.ToSliceOfBytes(),
-			LocalLastCommit:     buildExtendedCommitInfo(lastExtCommit, blockExec.store, state.InitialHeight),
+			LocalLastCommit:     buildExtendedCommitInfo(lastExtCommit, blockExec.store, state.InitialHeight, state.ConsensusParams.Vote),
 			ByzantineValidators: block.Evidence.ToABCI(),
 			Height:              block.Height,
 			Time:                block.Time,
@@ -321,7 +321,7 @@ func (blockExec *BlockExecutor) VerifyVoteExtension(ctx context.Context, vote *t
 	}
 
 	if !resp.IsOK() {
-		return types.ErrVoteInvalidExtension
+		return errors.New("invalid vote extension")
 	}
 
 	return nil
@@ -428,7 +428,7 @@ func buildLastCommitInfo(block *types.Block, store Store, initialHeight int64) a
 // data, it returns an empty record.
 //
 // Assumes that the commit signatures are sorted according to validator index.
-func buildExtendedCommitInfo(ec *types.ExtendedCommit, store Store, initialHeight int64) abci.ExtendedCommitInfo {
+func buildExtendedCommitInfo(ec *types.ExtendedCommit, store Store, initialHeight int64, vp types.VoteParams) abci.ExtendedCommitInfo {
 	if ec.Height < initialHeight {
 		// There are no extended commits for heights below the initial height.
 		return abci.ExtendedCommitInfo{}
@@ -466,12 +466,12 @@ func buildExtendedCommitInfo(ec *types.ExtendedCommit, store Store, initialHeigh
 		}
 
 		var ext []byte
-		if ecs.BlockIDFlag == types.BlockIDFlagCommit {
-			// We only care about vote extensions if a validator has voted to
-			// commit.
-			ext = ecs.Extension
+		if err := ecs.EnsureExtension(); err != nil && vp.RequireExtensions(ec.Height) {
+			panic(fmt.Errorf("commit at height %d received with missing vote extensions data", ec.Height))
 		}
 
+		ext = ecs.Extension
+
 		votes[i] = abci.ExtendedVoteInfo{
 			Validator:       types.TM2PB.Validator(val),
 			SignedLastBlock: ecs.BlockIDFlag != types.BlockIDFlagAbsent,

internal/statesync/reactor_test.go

@@ -855,7 +855,7 @@ func mockLB(ctx context.Context, t *testing.T, height int64, time time.Time, las
 	header.NextValidatorsHash = nextVals.Hash()
 	header.ConsensusHash = types.DefaultConsensusParams().HashConsensusParams()
 	lastBlockID = factory.MakeBlockIDWithHash(header.Hash())
-	voteSet := types.NewVoteSet(factory.DefaultTestChainID, height, 0, tmproto.PrecommitType, currentVals)
+	voteSet := types.NewVoteSet(factory.DefaultTestChainID, height, 0, tmproto.PrecommitType, currentVals, false)
 	extCommit, err := factory.MakeExtendedCommit(ctx, lastBlockID, height, 0, voteSet, currentPrivVals, time)
 	require.NoError(t, err)
 	return nextVals, nextPrivVals, &types.LightBlock{