Merge pull request #2462 from nspcc-dev/block-destroyed

core: block destroyed contracts and restrict maximum contract updates

pkg/core/native/contract.go

@@ -82,6 +82,7 @@ func NewContracts(cfg config.ProtocolConfiguration) *Contracts {
 	neo.Policy = policy
 	gas.NEO = neo
 	mgmt.NEO = neo
+	mgmt.Policy = policy
 	policy.NEO = neo
 
 	cs.GAS = gas

pkg/core/native/management.go

@@ -28,7 +28,8 @@ import (
 // Management is contract-managing native contract.
 type Management struct {
 	interop.ContractMD
-	NEO *NEO
+	NEO    *NEO
+	Policy *Policy
 }
 
 type ManagementCache struct {
@@ -286,6 +287,9 @@ func (m *Management) markUpdated(d *dao.Simple, hash util.Uint160, cs *state.Con
 // It doesn't run _deploy method and doesn't emit notification.
 func (m *Management) Deploy(d *dao.Simple, sender util.Uint160, neff *nef.File, manif *manifest.Manifest) (*state.Contract, error) {
 	h := state.CreateContractHash(sender, neff.Checksum, manif.Name)
+	if m.Policy.IsBlocked(d, h) {
+		return nil, fmt.Errorf("the contract %s has been blocked", h.StringLE())
+	}
 	_, err := m.GetContract(d, h)
 	if err == nil {
 		return nil, errors.New("contract already exists")
@@ -349,6 +353,9 @@ func (m *Management) Update(d *dao.Simple, hash util.Uint160, neff *nef.File, ma
 	if err != nil {
 		return nil, errors.New("contract doesn't exist")
 	}
+	if oldcontract.UpdateCounter == math.MaxUint16 {
+		return nil, errors.New("the contract reached the maximum number of updates")
+	}
 
 	contract = *oldcontract // Make a copy, don't ruin (potentially) cached contract.
 	// if NEF was provided, update the contract script
@@ -404,6 +411,7 @@ func (m *Management) Destroy(d *dao.Simple, hash util.Uint160) error {
 		d.DeleteStorageItem(contract.ID, k)
 		return true
 	})
+	m.Policy.blockAccountInternal(d, hash)
 	m.markUpdated(d, hash, nil)
 	return nil
 }

pkg/core/native/management_test.go

@@ -17,9 +17,11 @@ import (
 
 func TestDeployGetUpdateDestroyContract(t *testing.T) {
 	mgmt := newManagement()
+	mgmt.Policy = newPolicy()
 	d := dao.NewSimple(storage.NewMemoryStore(), false, false)
 	err := mgmt.Initialize(&interop.Context{DAO: d})
 	require.NoError(t, err)
+	require.NoError(t, mgmt.Policy.Initialize(&interop.Context{DAO: d}))
 	script := []byte{byte(opcode.RET)}
 	sender := util.Uint160{1, 2, 3}
 	ne, err := nef.NewFile(script)
@@ -86,9 +88,11 @@ func TestManagement_Initialize(t *testing.T) {
 
 func TestManagement_GetNEP17Contracts(t *testing.T) {
 	mgmt := newManagement()
+	mgmt.Policy = newPolicy()
 	d := dao.NewSimple(storage.NewMemoryStore(), false, false)
 	err := mgmt.Initialize(&interop.Context{DAO: d})
 	require.NoError(t, err)
+	require.NoError(t, mgmt.Policy.Initialize(&interop.Context{DAO: d}))
 	err = mgmt.InitializeCache(d)
 	require.NoError(t, err)
 

pkg/core/native/native_test/management_test.go

@@ -563,5 +563,7 @@ func TestManagement_ContractDestroy(t *testing.T) {
 		t.Run("check contract", func(t *testing.T) {
 			managementInvoker.Invoke(t, stackitem.Null{}, "getContract", cs1.Hash.BytesBE())
 		})
+		// deploy after destroy should fail
+		managementInvoker.InvokeFail(t, fmt.Sprintf("the contract %s has been blocked", cs1.Hash.StringLE()), "deploy", nefBytes, manifestBytes)
 	})
 }

pkg/core/native/policy.go

@@ -317,20 +317,23 @@ func (p *Policy) blockAccount(ic *interop.Context, args []stackitem.Item) stacki
 			panic("cannot block native contract")
 		}
 	}
-	i, blocked := p.isBlockedInternal(ic.DAO, hash)
+	return stackitem.NewBool(p.blockAccountInternal(ic.DAO, hash))
+}
+func (p *Policy) blockAccountInternal(d *dao.Simple, hash util.Uint160) bool {
+	i, blocked := p.isBlockedInternal(d, hash)
 	if blocked {
-		return stackitem.NewBool(false)
+		return false
 	}
 	key := append([]byte{blockedAccountPrefix}, hash.BytesBE()...)
-	ic.DAO.PutStorageItem(p.ID, key, state.StorageItem{})
-	cache := ic.DAO.GetRWCache(p.ID).(*PolicyCache)
+	d.PutStorageItem(p.ID, key, state.StorageItem{})
+	cache := d.GetRWCache(p.ID).(*PolicyCache)
 	if len(cache.blockedAccounts) == i {
 		cache.blockedAccounts = append(cache.blockedAccounts, hash)
 	} else {
 		cache.blockedAccounts = append(cache.blockedAccounts[:i+1], cache.blockedAccounts[i:]...)
 		cache.blockedAccounts[i] = hash
 	}
-	return stackitem.NewBool(true)
+	return true
 }
 
 // unblockAccount is Policy contract method and removes given account hash from