stateroot: use RoleStateValidator for verification

internal/fakechain/fakechain.go

@@ -276,7 +276,7 @@ func (chain *FakeChain) GetEnrollments() ([]state.Validator, error) {
 
 // GetStateModule implements Blockchainer interface.
 func (chain *FakeChain) GetStateModule() blockchainer.StateRoot {
-	panic("TODO")
+	return nil
 }
 
 // GetStorageItem implements Blockchainer interface.

pkg/core/blockchain.go

@@ -196,6 +196,7 @@ func NewBlockchain(s storage.Store, cfg config.ProtocolConfiguration, log *zap.L
 	}
 
 	bc.stateRoot = stateroot.NewModule(bc, bc.log, bc.dao.Store)
+	bc.contracts.Designate.StateRootService = bc.stateRoot
 
 	if err := bc.init(); err != nil {
 		return nil, err

pkg/core/blockchainer/state_root.go

@@ -2,12 +2,16 @@ package blockchainer
 
 import (
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
 // StateRoot represents local state root module.
 type StateRoot interface {
+	AddStateRoot(root *state.MPTRoot) error
 	CurrentLocalStateRoot() util.Uint256
+	CurrentValidatedHeight() uint32
 	GetStateProof(root util.Uint256, key []byte) ([][]byte, error)
 	GetStateRoot(height uint32) (*state.MPTRoot, error)
+	UpdateStateValidators(height uint32, pubs keys.PublicKeys)
 }

pkg/core/native/designate.go

@@ -7,6 +7,7 @@ import (
 	"sort"
 	"sync/atomic"
 
+	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
@@ -40,6 +41,8 @@ type Designate struct {
 	OracleService atomic.Value
 	// NotaryService represents Notary node module.
 	NotaryService atomic.Value
+	// StateRootService represents StateRoot node module.
+	StateRootService blockchainer.StateRoot
 }
 
 type roleData struct {
@@ -172,12 +175,10 @@ func (s *Designate) hashFromNodes(r Role, nodes keys.PublicKeys) util.Uint160 {
 	}
 	var script []byte
 	switch r {
-	case RoleOracle, RoleNeoFSAlphabet:
-		script, _ = smartcontract.CreateDefaultMultiSigRedeemScript(nodes.Copy())
 	case RoleP2PNotary:
 		script, _ = smartcontract.CreateMultiSigRedeemScript(1, nodes.Copy())
 	default:
-		script, _ = smartcontract.CreateMajorityMultiSigRedeemScript(nodes.Copy())
+		script, _ = smartcontract.CreateDefaultMultiSigRedeemScript(nodes.Copy())
 	}
 	return hash.Hash160(script)
 }
@@ -201,6 +202,10 @@ func (s *Designate) updateCachedRoleData(v *atomic.Value, d dao.DAO, r Role) err
 		if ntr, _ := s.NotaryService.Load().(services.Notary); ntr != nil {
 			ntr.UpdateNotaryNodes(nodeKeys.Copy())
 		}
+	case RoleStateValidator:
+		if s.StateRootService != nil {
+			s.StateRootService.UpdateStateValidators(height, nodeKeys.Copy())
+		}
 	}
 	return nil
 }

pkg/core/stateroot/module.go

@@ -1,12 +1,16 @@
 package stateroot
 
 import (
+	"encoding/binary"
+	"errors"
 	"fmt"
+	"sync"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
 	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"go.uber.org/atomic"
 	"go.uber.org/zap"
@@ -20,9 +24,19 @@ type (
 		bc    blockchainer.Blockchainer
 		log   *zap.Logger
 
+		currentLocal    atomic.Value
 		localHeight     atomic.Uint32
 		validatedHeight atomic.Uint32
-		currentLocal    atomic.Value
+
+		mtx  sync.RWMutex
+		keys []keyCache
+	}
+
+	keyCache struct {
+		height           uint32
+		validatorsKeys   keys.PublicKeys
+		validatorsHash   util.Uint160
+		validatorsScript []byte
 	}
 )
 
@@ -51,8 +65,18 @@ func (s *Module) CurrentLocalStateRoot() util.Uint256 {
 	return s.currentLocal.Load().(util.Uint256)
 }
 
+// CurrentValidatedHeight returns current state root validated height.
+func (s *Module) CurrentValidatedHeight() uint32 {
+	return s.validatedHeight.Load()
+}
+
 // Init initializes state root module at the given height.
 func (s *Module) Init(height uint32, enableRefCount bool) error {
+	data, err := s.Store.Get([]byte{byte(storage.DataMPT), prefixValidated})
+	if err == nil {
+		s.validatedHeight.Store(binary.LittleEndian.Uint32(data))
+	}
+
 	var gcKey = []byte{byte(storage.DataMPT), prefixGC}
 	if height == 0 {
 		s.mpt = mpt.NewTrie(nil, enableRefCount, s.Store)
@@ -96,3 +120,22 @@ func (s *Module) AddMPTBatch(index uint32, b mpt.Batch) error {
 	_, err = s.Store.Persist()
 	return err
 }
+
+// VerifyStateRoot checks if state root is valid.
+func (s *Module) VerifyStateRoot(r *state.MPTRoot) error {
+	_, err := s.getStateRoot(makeStateRootKey(r.Index - 1))
+	if err != nil {
+		return errors.New("can't get previous state root")
+	}
+	return s.verifyWitness(r)
+}
+
+const maxVerificationGAS = 1_00000000
+
+// verifyWitness verifies state root witness.
+func (s *Module) verifyWitness(r *state.MPTRoot) error {
+	s.mtx.Lock()
+	h := s.getKeyCacheForHeight(r.Index).validatorsHash
+	s.mtx.Unlock()
+	return s.bc.VerifyWitness(h, r, r.Witness, maxVerificationGAS)
+}

pkg/core/stateroot/store.go

@@ -11,6 +11,7 @@ import (
 const (
 	prefixGC        = 0x01
 	prefixLocal     = 0x02
+	prefixValidated = 0x03
 )
 
 func (s *Module) addLocalStateRoot(sr *state.MPTRoot) error {
@@ -26,7 +27,10 @@ func (s *Module) addLocalStateRoot(sr *state.MPTRoot) error {
 	}
 	s.currentLocal.Store(sr.Root)
 	s.localHeight.Store(sr.Index)
+	if s.bc.GetConfig().StateRootInHeader {
+		s.validatedHeight.Store(sr.Index)
 		updateStateHeightMetric(sr.Index)
+	}
 	return nil
 }
 
@@ -54,3 +58,32 @@ func makeStateRootKey(index uint32) []byte {
 	binary.BigEndian.PutUint32(key, index)
 	return key
 }
+
+// AddStateRoot adds validated state root provided by network.
+func (s *Module) AddStateRoot(sr *state.MPTRoot) error {
+	if err := s.VerifyStateRoot(sr); err != nil {
+		return err
+	}
+	key := makeStateRootKey(sr.Index)
+	local, err := s.getStateRoot(key)
+	if err != nil {
+		return err
+	}
+	if local.Witness != nil {
+		return nil
+	}
+	if err := s.putStateRoot(key, sr); err != nil {
+		return err
+	}
+
+	data := make([]byte, 4)
+	binary.LittleEndian.PutUint32(data, sr.Index)
+	if err := s.Store.Put([]byte{byte(storage.DataMPT), prefixValidated}, data); err != nil {
+		return err
+	}
+	s.validatedHeight.Store(sr.Index)
+	if !s.bc.GetConfig().StateRootInHeader {
+		updateStateHeightMetric(sr.Index)
+	}
+	return nil
+}

pkg/core/stateroot/validators.go

@@ -0,0 +1,37 @@
+package stateroot
+
+import (
+	"sort"
+
+	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+)
+
+// UpdateStateValidators updates list of state validator keys.
+func (s *Module) UpdateStateValidators(height uint32, pubs keys.PublicKeys) {
+	script, _ := smartcontract.CreateDefaultMultiSigRedeemScript(pubs)
+	h := hash.Hash160(script)
+
+	s.mtx.Lock()
+	kc := s.getKeyCacheForHeight(height)
+	if kc.validatorsHash != h {
+		s.keys = append(s.keys, keyCache{
+			height:           height,
+			validatorsKeys:   pubs,
+			validatorsHash:   h,
+			validatorsScript: script,
+		})
+	}
+	s.mtx.Unlock()
+}
+
+func (s *Module) getKeyCacheForHeight(h uint32) keyCache {
+	index := sort.Search(len(s.keys), func(i int) bool {
+		return s.keys[i].height >= h
+	})
+	if index == len(s.keys) {
+		return keyCache{}
+	}
+	return s.keys[index]
+}

pkg/core/stateroot_test.go

@@ -0,0 +1,153 @@
+package core
+
+import (
+	"errors"
+	"sort"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/internal/testserdes"
+	"github.com/nspcc-dev/neo-go/pkg/core/native"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/network/payload"
+	"github.com/nspcc-dev/neo-go/pkg/services/stateroot"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
+	"github.com/nspcc-dev/neo-go/pkg/wallet"
+	"github.com/stretchr/testify/require"
+)
+
+func testSignStateRoot(t *testing.T, r *state.MPTRoot, pubs keys.PublicKeys, accs ...*wallet.Account) []byte {
+	n := smartcontract.GetMajorityHonestNodeCount(len(accs))
+	w := io.NewBufBinWriter()
+	for i := 0; i < n; i++ {
+		sig := accs[i].PrivateKey().SignHash(r.GetSignedHash())
+		emit.Bytes(w.BinWriter, sig)
+	}
+	require.NoError(t, w.Err)
+
+	script, err := smartcontract.CreateMajorityMultiSigRedeemScript(pubs.Copy())
+	require.NoError(t, err)
+	r.Witness = &transaction.Witness{
+		VerificationScript: script,
+		InvocationScript:   w.Bytes(),
+	}
+	data, err := testserdes.EncodeBinary(stateroot.NewMessage(stateroot.RootT, r))
+	require.NoError(t, err)
+	return data
+}
+
+func newMajorityMultisigWithGAS(t *testing.T, n int) (util.Uint160, keys.PublicKeys, []*wallet.Account) {
+	accs := make([]*wallet.Account, n)
+	for i := range accs {
+		acc, err := wallet.NewAccount()
+		require.NoError(t, err)
+		accs[i] = acc
+	}
+	sort.Slice(accs, func(i, j int) bool {
+		pi := accs[i].PrivateKey().PublicKey()
+		pj := accs[j].PrivateKey().PublicKey()
+		return pi.Cmp(pj) == -1
+	})
+	pubs := make(keys.PublicKeys, n)
+	for i := range pubs {
+		pubs[i] = accs[i].PrivateKey().PublicKey()
+	}
+	script, err := smartcontract.CreateMajorityMultiSigRedeemScript(pubs)
+	require.NoError(t, err)
+	return hash.Hash160(script), pubs, accs
+}
+
+func TestStateRoot(t *testing.T) {
+	bc := newTestChain(t)
+
+	h, pubs, accs := newMajorityMultisigWithGAS(t, 2)
+	bc.setNodesByRole(t, true, native.RoleStateValidator, pubs)
+	updateIndex := bc.BlockHeight()
+	transferTokenFromMultisigAccount(t, bc, h, bc.contracts.GAS.Hash, 1_0000_0000)
+
+	srv, err := stateroot.New(bc.GetStateModule())
+	require.NoError(t, err)
+	require.EqualValues(t, 0, srv.CurrentValidatedHeight())
+	r, err := srv.GetStateRoot(bc.BlockHeight())
+	require.NoError(t, err)
+	require.Equal(t, r.Root, srv.CurrentLocalStateRoot())
+
+	t.Run("invalid message", func(t *testing.T) {
+		require.Error(t, srv.OnPayload(&payload.Extensible{Data: []byte{42}}))
+		require.EqualValues(t, 0, srv.CurrentValidatedHeight())
+	})
+	t.Run("drop zero index", func(t *testing.T) {
+		r, err := srv.GetStateRoot(0)
+		require.NoError(t, err)
+		data, err := testserdes.EncodeBinary(stateroot.NewMessage(stateroot.RootT, r))
+		require.NoError(t, err)
+		require.NoError(t, srv.OnPayload(&payload.Extensible{Data: data}))
+		require.EqualValues(t, 0, srv.CurrentValidatedHeight())
+	})
+	t.Run("invalid height", func(t *testing.T) {
+		r, err := srv.GetStateRoot(1)
+		require.NoError(t, err)
+		r.Index = 10
+		data := testSignStateRoot(t, r, pubs, accs...)
+		require.Error(t, srv.OnPayload(&payload.Extensible{Data: data}))
+		require.EqualValues(t, 0, srv.CurrentValidatedHeight())
+	})
+	t.Run("invalid signer", func(t *testing.T) {
+		accInv, err := wallet.NewAccount()
+		require.NoError(t, err)
+		pubs := keys.PublicKeys{accInv.PrivateKey().PublicKey()}
+		require.NoError(t, accInv.ConvertMultisig(1, pubs))
+		transferTokenFromMultisigAccount(t, bc, accInv.Contract.ScriptHash(), bc.contracts.GAS.Hash, 1_0000_0000)
+		r, err := srv.GetStateRoot(1)
+		require.NoError(t, err)
+		data := testSignStateRoot(t, r, pubs, accInv)
+		err = srv.OnPayload(&payload.Extensible{Data: data})
+		require.True(t, errors.Is(err, ErrWitnessHashMismatch), "got: %v", err)
+		require.EqualValues(t, 0, srv.CurrentValidatedHeight())
+	})
+
+	r, err = srv.GetStateRoot(updateIndex + 1)
+	require.NoError(t, err)
+	data := testSignStateRoot(t, r, pubs, accs...)
+	require.NoError(t, srv.OnPayload(&payload.Extensible{Data: data}))
+	require.EqualValues(t, 2, srv.CurrentValidatedHeight())
+
+	r, err = srv.GetStateRoot(updateIndex + 1)
+	require.NoError(t, err)
+	require.NotNil(t, r.Witness)
+	require.Equal(t, h, r.Witness.ScriptHash())
+}
+
+func TestStateRootInitNonZeroHeight(t *testing.T) {
+	st := memoryStore{storage.NewMemoryStore()}
+	h, pubs, accs := newMajorityMultisigWithGAS(t, 2)
+
+	var root util.Uint256
+	t.Run("init", func(t *testing.T) { // this is in a separate test to do proper cleanup
+		bc := newTestChainWithCustomCfgAndStore(t, st, nil)
+		bc.setNodesByRole(t, true, native.RoleStateValidator, pubs)
+		transferTokenFromMultisigAccount(t, bc, h, bc.contracts.GAS.Hash, 1_0000_0000)
+
+		_, err := persistBlock(bc)
+		require.NoError(t, err)
+		srv, err := stateroot.New(bc.GetStateModule())
+		require.NoError(t, err)
+		r, err := srv.GetStateRoot(2)
+		require.NoError(t, err)
+		data := testSignStateRoot(t, r, pubs, accs...)
+		require.NoError(t, srv.OnPayload(&payload.Extensible{Data: data}))
+		require.EqualValues(t, 2, srv.CurrentValidatedHeight())
+		root = srv.CurrentLocalStateRoot()
+	})
+
+	bc2 := newTestChainWithCustomCfgAndStore(t, st, nil)
+	srv := bc2.GetStateModule()
+	require.EqualValues(t, 2, srv.CurrentValidatedHeight())
+	require.Equal(t, root, srv.CurrentLocalStateRoot())
+}

pkg/network/server.go

@@ -22,6 +22,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/network/payload"
 	"github.com/nspcc-dev/neo-go/pkg/services/notary"
 	"github.com/nspcc-dev/neo-go/pkg/services/oracle"
+	"github.com/nspcc-dev/neo-go/pkg/services/stateroot"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"go.uber.org/atomic"
 	"go.uber.org/zap"
@@ -88,6 +89,7 @@ type (
 		canHandleExtens  *atomic.Bool
 
 		oracle    *oracle.Oracle
+		stateRoot stateroot.Service
 
 		log *zap.Logger
 	}
@@ -171,6 +173,12 @@ func newServerFromConstructors(config ServerConfig, chain blockchainer.Blockchai
 		}
 	})
 
+	sr, err := stateroot.New(chain.GetStateModule())
+	if err != nil {
+		return nil, fmt.Errorf("can't initialize StateRoot service: %w", err)
+	}
+	s.stateRoot = sr
+
 	if config.OracleCfg.Enabled {
 		orcCfg := oracle.Config{
 			Log:     log,
@@ -295,6 +303,11 @@ func (s *Server) GetOracle() *oracle.Oracle {
 	return s.oracle
 }
 
+// GetStateRoot returns state root service instance.
+func (s *Server) GetStateRoot() stateroot.Service {
+	return s.stateRoot
+}
+
 // UnconnectedPeers returns a list of peers that are in the discovery peer list
 // but are not connected to the server.
 func (s *Server) UnconnectedPeers() []string {
@@ -803,7 +816,11 @@ func (s *Server) handleExtensibleCmd(e *payload.Extensible) error {
 	switch e.Category {
 	case consensus.Category:
 		s.consensus.OnPayload(e)
-	case "StateService": // no-op for now
+	case stateroot.Category:
+		err := s.stateRoot.OnPayload(e)
+		if err != nil {
+			return err
+		}
 	default:
 		return errors.New("invalid category")
 	}

pkg/rpc/server/server.go

@@ -869,7 +869,7 @@ func (s *Server) verifyProof(ps request.Params) (interface{}, *response.Error) {
 
 func (s *Server) getStateHeight(_ request.Params) (interface{}, *response.Error) {
 	var height = s.chain.BlockHeight()
-	var stateHeight uint32
+	var stateHeight = s.chain.GetStateModule().CurrentValidatedHeight()
 	if s.chain.GetConfig().StateRootInHeader {
 		stateHeight = height - 1
 	}

pkg/services/stateroot/message.go

@@ -0,0 +1,50 @@
+package stateroot
+
+import (
+	"fmt"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/io"
+)
+
+type (
+	// MessageType represents message type.
+	MessageType byte
+
+	// Message represents state-root related message.
+	Message struct {
+		Type    MessageType
+		Payload io.Serializable
+	}
+)
+
+// Various message types.
+const (
+	RootT MessageType = 1
+)
+
+// NewMessage creates new message of specified type.
+func NewMessage(typ MessageType, p io.Serializable) *Message {
+	return &Message{
+		Type:    typ,
+		Payload: p,
+	}
+}
+
+// EncodeBinary implements io.Serializable interface.
+func (m *Message) EncodeBinary(w *io.BinWriter) {
+	w.WriteB(byte(m.Type))
+	m.Payload.EncodeBinary(w)
+}
+
+// DecodeBinary implements io.Serializable interface.
+func (m *Message) DecodeBinary(r *io.BinReader) {
+	switch m.Type = MessageType(r.ReadB()); m.Type {
+	case RootT:
+		m.Payload = new(state.MPTRoot)
+	default:
+		r.Err = fmt.Errorf("invalid type: %x", m.Type)
+		return
+	}
+	m.Payload.DecodeBinary(r)
+}

pkg/services/stateroot/service.go

@@ -0,0 +1,51 @@
+package stateroot
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/network/payload"
+)
+
+type (
+	// Service represents state root service.
+	Service interface {
+		blockchainer.StateRoot
+		OnPayload(p *payload.Extensible) error
+	}
+
+	service struct {
+		blockchainer.StateRoot
+	}
+)
+
+const (
+	// Category is message category for extensible payloads.
+	Category = "StateService"
+)
+
+// New returns new state root service instance using underlying module.
+func New(mod blockchainer.StateRoot) (Service, error) {
+	return &service{
+		StateRoot: mod,
+	}, nil
+}
+
+// OnPayload implements Service interface.
+func (s *service) OnPayload(ep *payload.Extensible) error {
+	m := new(Message)
+	r := io.NewBinReaderFromBuf(ep.Data)
+	m.DecodeBinary(r)
+	if r.Err != nil {
+		return r.Err
+	}
+	switch m.Type {
+	case RootT:
+		sr := m.Payload.(*state.MPTRoot)
+		if sr.Index == 0 {
+			return nil
+		}
+		return s.AddStateRoot(sr)
+	}
+	return nil
+}