Merge pull request #578 from nspcc-dev/fix/sign

consensus: verify payloads correctly, closes #555.

pkg/consensus/consensus.go

@@ -9,6 +9,7 @@ import (
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
+	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
 	"github.com/CityOfZion/neo-go/pkg/smartcontract"
 	"github.com/CityOfZion/neo-go/pkg/util"
@@ -163,6 +164,19 @@ func (s *service) eventLoop() {
 	}
 }
 
+func (s *service) validatePayload(p *Payload) bool {
+	validators := s.getValidators()
+	if int(p.validatorIndex) >= len(validators) {
+		return false
+	}
+
+	pub := validators[p.validatorIndex]
+	vs := pub.(*publicKey).GetVerificationScript()
+	h := hash.Hash160(vs)
+
+	return p.Verify(h)
+}
+
 func getKeyPair(cfg *config.WalletConfig) (crypto.PrivateKey, crypto.PublicKey) {
 	acc, err := wallet.DecryptAccount(cfg.Path, cfg.Password)
 	if err != nil {
@@ -179,10 +193,7 @@ func getKeyPair(cfg *config.WalletConfig) (crypto.PrivateKey, crypto.PublicKey)
 
 // OnPayload handles Payload receive.
 func (s *service) OnPayload(cp *Payload) {
-	if !cp.Verify() {
+	if !s.validatePayload(cp) || s.cache.Has(cp.Hash()) {
-		s.log.Debug("can't verify payload from #%d", cp.validatorIndex)
-		return
-	} else if s.cache.Has(cp.Hash()) {
 		return
 	}
 

pkg/consensus/consensus_test.go

@@ -27,6 +27,35 @@ func TestNewService(t *testing.T) {
 	require.Equal(t, tx, txx[1])
 }
 
+func TestService_ValidatePayload(t *testing.T) {
+	srv := newTestService(t)
+	priv, _ := getTestValidator(1)
+	p := new(Payload)
+
+	p.SetPayload(&prepareRequest{})
+
+	t.Run("invalid validator index", func(t *testing.T) {
+		p.SetValidatorIndex(11)
+		require.NoError(t, p.Sign(priv))
+
+		var ok bool
+		require.NotPanics(t, func() { ok = srv.validatePayload(p) })
+		require.False(t, ok)
+	})
+
+	t.Run("wrong validator index", func(t *testing.T) {
+		p.SetValidatorIndex(2)
+		require.NoError(t, p.Sign(priv))
+		require.False(t, srv.validatePayload(p))
+	})
+
+	t.Run("normal case", func(t *testing.T) {
+		p.SetValidatorIndex(1)
+		require.NoError(t, p.Sign(priv))
+		require.True(t, srv.validatePayload(p))
+	})
+}
+
 func TestService_OnPayload(t *testing.T) {
 	srv := newTestService(t)
 

pkg/consensus/payload.go

@@ -4,6 +4,7 @@ import (
 	"crypto/sha256"
 	"fmt"
 
+	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/io"
@@ -195,18 +196,27 @@ func (p *Payload) Sign(key *privateKey) error {
 }
 
 // Verify verifies payload using provided Witness.
-func (p *Payload) Verify() bool {
+func (p *Payload) Verify(scriptHash util.Uint160) bool {
-	h := sha256.Sum256(p.MarshalUnsigned())
+	verification, err := core.ScriptFromWitness(scriptHash, &p.Witness)
-	v := vm.New()
+	if err != nil {
-	v.SetCheckedHash(h[:])
-	v.Load(append(p.Witness.InvocationScript, p.Witness.VerificationScript...))
-	if err := v.Run(); err != nil || v.Estack().Len() == 0 {
 		return false
 	}
 
-	result, err := v.Estack().Top().TryBool()
+	v := vm.New()
+	h := sha256.Sum256(p.MarshalUnsigned())
 
-	return err == nil && result
+	v.SetCheckedHash(h[:])
+	v.LoadScript(verification)
+	v.LoadScript(p.Witness.InvocationScript)
+
+	err = v.Run()
+	if err != nil || v.HasFailed() || v.Estack().Len() != 1 {
+		return false
+	}
+
+	res, err := v.Estack().Pop().TryBool()
+
+	return err == nil && res
 }
 
 // DecodeBinaryUnsigned reads payload from w excluding signature.

pkg/consensus/payload_test.go

@@ -300,9 +300,9 @@ func TestPayload_Sign(t *testing.T) {
 
 	priv := &privateKey{key}
 	p := randomPayload(t, prepareRequestType)
-	require.False(t, p.Verify())
+	require.False(t, p.Verify(util.Uint160{}))
 	require.NoError(t, p.Sign(priv))
-	require.True(t, p.Verify())
+	require.True(t, p.Verify(p.Witness.ScriptHash()))
 }
 
 func TestMessageType_String(t *testing.T) {

pkg/consensus/recovery_message_test.go

@@ -55,7 +55,8 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 		ps := r.GetPrepareResponses(p, pubs)
 		require.Len(t, ps, 1)
 		require.Equal(t, p2, ps[0])
-		require.True(t, ps[0].(*Payload).Verify())
+		ps0 := ps[0].(*Payload)
+		require.True(t, ps0.Verify(ps0.Witness.ScriptHash()))
 	})
 
 	t.Run("prepare request is added", func(t *testing.T) {
@@ -66,7 +67,9 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 		pr = r.GetPrepareRequest(p, pubs, p1.ValidatorIndex())
 		require.NotNil(t, pr)
 		require.Equal(t, p1, pr)
-		require.True(t, pr.(*Payload).Verify())
+
+		pl := pr.(*Payload)
+		require.True(t, pl.Verify(pl.Witness.ScriptHash()))
 	})
 
 	t.Run("change view is added", func(t *testing.T) {
@@ -84,7 +87,9 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 		ps := r.GetChangeViews(p, pubs)
 		require.Len(t, ps, 1)
 		require.Equal(t, p3, ps[0])
-		require.True(t, ps[0].(*Payload).Verify())
+
+		ps0 := ps[0].(*Payload)
+		require.True(t, ps0.Verify(ps0.Witness.ScriptHash()))
 	})
 
 	t.Run("commit is added", func(t *testing.T) {
@@ -99,7 +104,9 @@ func TestRecoveryMessage_Setters(t *testing.T) {
 		ps := r.GetCommits(p, pubs)
 		require.Len(t, ps, 1)
 		require.Equal(t, p4, ps[0])
-		require.True(t, ps[0].(*Payload).Verify())
+
+		ps0 := ps[0].(*Payload)
+		require.True(t, ps0.Verify(ps0.Witness.ScriptHash()))
 	})
 }
 

pkg/core/blockchain.go

@@ -1372,21 +1372,30 @@ func (bc *Blockchain) GetTestVM() (*vm.VM, storage.Store) {
 	return vm, tmpStore
 }
 
-// verifyHashAgainstScript verifies given hash against the given witness.
+// ScriptFromWitness returns verification script for provided witness.
-func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transaction.Witness, checkedHash util.Uint256, interopCtx *interopContext, useKeys bool) error {
+// If hash is not equal to the witness script hash, error is returned.
+func ScriptFromWitness(hash util.Uint160, witness *transaction.Witness) ([]byte, error) {
 	verification := witness.VerificationScript
 
 	if len(verification) == 0 {
 		bb := new(bytes.Buffer)
 		err := vm.EmitAppCall(bb, hash, false)
 		if err != nil {
-			return err
+			return nil, err
 		}
 		verification = bb.Bytes()
-	} else {
+	} else if h := witness.ScriptHash(); hash != h {
-		if h := witness.ScriptHash(); hash != h {
+		return nil, errors.New("witness hash mismatch")
-			return errors.New("witness hash mismatch")
 	}
+
+	return verification, nil
+}
+
+// verifyHashAgainstScript verifies given hash against the given witness.
+func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transaction.Witness, checkedHash util.Uint256, interopCtx *interopContext, useKeys bool) error {
+	verification, err := ScriptFromWitness(hash, witness)
+	if err != nil {
+		return err
 	}
 
 	vm := bc.spawnVMWithInterops(interopCtx)
@@ -1396,7 +1405,7 @@ func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transa
 	if useKeys && bc.keyCache[hash] != nil {
 		vm.SetPublicKeys(bc.keyCache[hash])
 	}
-	err := vm.Run()
+	err = vm.Run()
 	if vm.HasFailed() {
 		return errors.Errorf("vm failed to execute the script with error: %s", err)
 	}

pkg/core/blockchain_test.go

@@ -4,7 +4,10 @@ import (
 	"testing"
 
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
+	"github.com/CityOfZion/neo-go/pkg/core/transaction"
+	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/io"
+	"github.com/CityOfZion/neo-go/pkg/util"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -65,6 +68,27 @@ func TestAddBlock(t *testing.T) {
 	assert.Equal(t, lastBlock.Hash(), bc.CurrentHeaderHash())
 }
 
+func TestScriptFromWitness(t *testing.T) {
+	witness := &transaction.Witness{}
+	h := util.Uint160{1, 2, 3}
+
+	res, err := ScriptFromWitness(h, witness)
+	require.NoError(t, err)
+	require.NotNil(t, res)
+
+	witness.VerificationScript = []byte{4, 8, 15, 16, 23, 42}
+	h = hash.Hash160(witness.VerificationScript)
+
+	res, err = ScriptFromWitness(h, witness)
+	require.NoError(t, err)
+	require.NotNil(t, res)
+
+	h[0] = ^h[0]
+	res, err = ScriptFromWitness(h, witness)
+	require.Error(t, err)
+	require.Nil(t, res)
+}
+
 func TestGetHeader(t *testing.T) {
 	bc := newTestChain(t)
 	block := newBlock(1, newMinerTX())