Merge pull request #1187 from nspcc-dev/neo3/interop/post-preview2_adjustment

interop: post-preview2 adjustment

pkg/compiler/codegen.go

@@ -1139,14 +1139,13 @@ func (c *codegen) getByteArray(expr ast.Expr) []byte {
 }
 
 func (c *codegen) convertSyscall(expr *ast.CallExpr, api, name string) {
-	api, ok := syscalls[api][name]
+	syscall, ok := syscalls[api][name]
 	if !ok {
-		c.prog.Err = fmt.Errorf("unknown VM syscall api: %s", name)
+		c.prog.Err = fmt.Errorf("unknown VM syscall api: %s.%s", api, name)
 		return
 	}
-	emit.Syscall(c.prog.BinWriter, api)
-	switch name {
-	case "GetTransaction", "GetBlock", "GetScriptContainer":
+	emit.Syscall(c.prog.BinWriter, syscall.API)
+	if syscall.ConvertResultToStruct {
 		c.emitConvert(stackitem.StructT)
 	}
 

pkg/compiler/syscall.go

@@ -1,73 +1,81 @@
 package compiler
 
-var syscalls = map[string]map[string]string{
-	"binary": {
-		"Serialize":   "System.Binary.Serialize",
-		"Deserialize": "System.Binary.Deserialize",
-	},
-	"crypto": {
-		"ECDsaSecp256r1Verify":        "Neo.Crypto.VerifyWithECDsaSecp256r1",
-		"ECDsaSecp256k1Verify":        "Neo.Crypto.VerifyWithECDsaSecp256k1",
-		"ECDSASecp256r1CheckMultisig": "Neo.Crypto.CheckMultisigWithECDsaSecp256r1",
-		"ECDSASecp256k1CheckMultisig": "Neo.Crypto.CheckMultisigWithECDsaSecp256k1",
-	},
-	"enumerator": {
-		"Concat": "System.Enumerator.Concat",
-		"Create": "System.Enumerator.Create",
-		"Next":   "System.Enumerator.Next",
-		"Value":  "System.Enumerator.Value",
-	},
-	"json": {
-		"Serialize":   "System.Json.Serialize",
-		"Deserialize": "System.Json.Deserialize",
-	},
-	"storage": {
-		"ConvertContextToReadOnly": "System.Storage.AsReadOnly",
-		"Delete":                   "System.Storage.Delete",
-		"Find":                     "System.Storage.Find",
-		"Get":                      "System.Storage.Get",
-		"GetContext":               "System.Storage.GetContext",
-		"GetReadOnlyContext":       "System.Storage.GetReadOnlyContext",
-		"Put":                      "System.Storage.Put",
-	},
-	"runtime": {
-		"GetScriptContainer":     "System.Runtime.GetScriptContainer",
-		"GetCallingScriptHash":   "System.Runtime.GetCallingScriptHash",
-		"GetEntryScriptHash":     "System.Runtime.GetEntryScriptHash",
-		"GetExecutingScriptHash": "System.Runtime.GetExecutingScriptHash",
-		"GetNotifications":       "System.Runtime.GetNotifications",
-		"GetInvocationCounter":   "System.Runtime.GetInvocationCounter",
+// Syscall represents NEO or System syscall API with flag for proper AVM generation
+type Syscall struct {
+	API                   string
+	ConvertResultToStruct bool
+}
 
-		"GasLeft":      "System.Runtime.GasLeft",
-		"GetTrigger":   "System.Runtime.GetTrigger",
-		"CheckWitness": "System.Runtime.CheckWitness",
-		"Notify":       "System.Runtime.Notify",
-		"Log":          "System.Runtime.Log",
-		"GetTime":      "System.Runtime.GetTime",
+// All lists are sorted, keep 'em this way, please.
+var syscalls = map[string]map[string]Syscall{
+	"binary": {
+		"Base64Decode": {"System.Binary.Base64Decode", false},
+		"Base64Encode": {"System.Binary.Base64Encode", false},
+		"Deserialize":  {"System.Binary.Deserialize", false},
+		"Serialize":    {"System.Binary.Serialize", false},
 	},
 	"blockchain": {
-		"GetBlock":                "System.Blockchain.GetBlock",
-		"GetContract":             "System.Blockchain.GetContract",
-		"GetHeight":               "System.Blockchain.GetHeight",
-		"GetTransaction":          "System.Blockchain.GetTransaction",
-		"GetTransactionFromBlock": "System.Blockchain.GetTransactionFromBlock",
-		"GetTransactionHeight":    "System.Blockchain.GetTransactionHeight",
+		"GetBlock":                {"System.Blockchain.GetBlock", true},
+		"GetContract":             {"System.Blockchain.GetContract", true},
+		"GetHeight":               {"System.Blockchain.GetHeight", false},
+		"GetTransaction":          {"System.Blockchain.GetTransaction", true},
+		"GetTransactionFromBlock": {"System.Blockchain.GetTransactionFromBlock", false},
+		"GetTransactionHeight":    {"System.Blockchain.GetTransactionHeight", false},
 	},
 	"contract": {
-		"Create":  "System.Contract.Create",
-		"Destroy": "System.Contract.Destroy",
-		"Update":  "System.Contract.Update",
-
-		"IsStandard":            "System.Contract.IsStandard",
-		"CreateStandardAccount": "System.Contract.CreateStandardAccount",
+		"Create":                {"System.Contract.Create", true},
+		"CreateStandardAccount": {"System.Contract.CreateStandardAccount", false},
+		"Destroy":               {"System.Contract.Destroy", false},
+		"IsStandard":            {"System.Contract.IsStandard", false},
+		"GetCallFlags":          {"System.Contract.GetCallFlags", false},
+		"Update":                {"System.Contract.Update", false},
+	},
+	"crypto": {
+		"ECDsaSecp256k1Verify":        {"Neo.Crypto.VerifyWithECDsaSecp256k1", false},
+		"ECDSASecp256k1CheckMultisig": {"Neo.Crypto.CheckMultisigWithECDsaSecp256k1", false},
+		"ECDsaSecp256r1Verify":        {"Neo.Crypto.VerifyWithECDsaSecp256r1", false},
+		"ECDSASecp256r1CheckMultisig": {"Neo.Crypto.CheckMultisigWithECDsaSecp256r1", false},
+	},
+	"enumerator": {
+		"Concat": {"System.Enumerator.Concat", false},
+		"Create": {"System.Enumerator.Create", false},
+		"Next":   {"System.Enumerator.Next", false},
+		"Value":  {"System.Enumerator.Value", false},
 	},
 	"iterator": {
-		"Concat": "System.Iterator.Concat",
-		"Create": "System.Iterator.Create",
-		"Key":    "System.Iterator.Key",
-		"Keys":   "System.Iterator.Keys",
-		"Next":   "System.Enumerator.Next",
-		"Value":  "System.Enumerator.Value",
-		"Values": "System.Iterator.Values",
+		"Concat": {"System.Iterator.Concat", false},
+		"Create": {"System.Iterator.Create", false},
+		"Key":    {"System.Iterator.Key", false},
+		"Keys":   {"System.Iterator.Keys", false},
+		"Next":   {"System.Enumerator.Next", false},
+		"Value":  {"System.Enumerator.Value", false},
+		"Values": {"System.Iterator.Values", false},
+	},
+	"json": {
+		"Deserialize": {"System.Json.Deserialize", false},
+		"Serialize":   {"System.Json.Serialize", false},
+	},
+	"runtime": {
+		"GasLeft":                {"System.Runtime.GasLeft", false},
+		"GetInvocationCounter":   {"System.Runtime.GetInvocationCounter", false},
+		"GetCallingScriptHash":   {"System.Runtime.GetCallingScriptHash", false},
+		"GetEntryScriptHash":     {"System.Runtime.GetEntryScriptHash", false},
+		"GetExecutingScriptHash": {"System.Runtime.GetExecutingScriptHash", false},
+		"GetNotifications":       {"System.Runtime.GetNotifications", false},
+		"GetScriptContainer":     {"System.Runtime.GetScriptContainer", true},
+		"GetTime":                {"System.Runtime.GetTime", false},
+		"GetTrigger":             {"System.Runtime.GetTrigger", false},
+		"CheckWitness":           {"System.Runtime.CheckWitness", false},
+		"Log":                    {"System.Runtime.Log", false},
+		"Notify":                 {"System.Runtime.Notify", false},
+	},
+	"storage": {
+		"ConvertContextToReadOnly": {"System.Storage.AsReadOnly", false},
+		"Delete":                   {"System.Storage.Delete", false},
+		"Find":                     {"System.Storage.Find", false},
+		"Get":                      {"System.Storage.Get", false},
+		"GetContext":               {"System.Storage.GetContext", false},
+		"GetReadOnlyContext":       {"System.Storage.GetReadOnlyContext", false},
+		"Put":                      {"System.Storage.Put", false},
 	},
 }

pkg/core/interop_neo.go

@@ -2,12 +2,14 @@ package core
 
 import (
 	"bytes"
+	"encoding/base64"
 	"errors"
 	"fmt"
 	"sort"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
@@ -72,7 +74,7 @@ func createContractStateFromVM(ic *interop.Context, v *vm.VM) (*state.Contract,
 	var m manifest.Manifest
 	err := m.UnmarshalJSON(manifestBytes)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("unable to retrieve manifest from stack: %v", err)
 	}
 	return &state.Contract{
 		Script:   script,
@@ -95,52 +97,91 @@ func contractCreate(ic *interop.Context, v *vm.VM) error {
 		return err
 	}
 	newcontract.ID = id
+	if !newcontract.Manifest.IsValid(newcontract.ScriptHash()) {
+		return errors.New("failed to check contract script hash against manifest")
+	}
 	if err := ic.DAO.PutContractState(newcontract); err != nil {
 		return err
 	}
-	v.Estack().PushVal(stackitem.NewInterop(newcontract))
+	cs, err := contractToStackItem(newcontract)
+	if err != nil {
+		return fmt.Errorf("cannot convert contract to stack item: %v", err)
+	}
+	v.Estack().PushVal(cs)
 	return nil
 }
 
-// contractUpdate migrates a contract.
+// contractUpdate migrates a contract. This method assumes that Manifest and Script
+// of the contract can be updated independently.
 func contractUpdate(ic *interop.Context, v *vm.VM) error {
-	contract, err := ic.DAO.GetContractState(v.GetCurrentScriptHash())
+	contract, _ := ic.DAO.GetContractState(v.GetCurrentScriptHash())
 	if contract == nil {
 		return errors.New("contract doesn't exist")
 	}
-	newcontract, err := createContractStateFromVM(ic, v)
-	if err != nil {
-		return err
+	script := v.Estack().Pop().Bytes()
+	if len(script) > MaxContractScriptSize {
+		return errors.New("the script is too big")
 	}
-	if newcontract.Script != nil {
-		if l := len(newcontract.Script); l == 0 || l > MaxContractScriptSize {
+	manifestBytes := v.Estack().Pop().Bytes()
+	if len(manifestBytes) > manifest.MaxManifestSize {
+		return errors.New("manifest is too big")
+	}
+	if !v.AddGas(int64(StoragePrice * (len(script) + len(manifestBytes)))) {
+		return errGasLimitExceeded
+	}
+	// if script was provided, update the old contract script and Manifest.ABI hash
+	if l := len(script); l > 0 {
+		if l > MaxContractScriptSize {
 			return errors.New("invalid script len")
 		}
-		h := newcontract.ScriptHash()
-		if h.Equals(contract.ScriptHash()) {
+		newHash := hash.Hash160(script)
+		if newHash.Equals(contract.ScriptHash()) {
 			return errors.New("the script is the same")
-		} else if _, err := ic.DAO.GetContractState(h); err == nil {
+		} else if _, err := ic.DAO.GetContractState(newHash); err == nil {
 			return errors.New("contract already exists")
 		}
-		newcontract.ID = contract.ID
-		if err := ic.DAO.PutContractState(newcontract); err != nil {
-			return err
+		oldHash := contract.ScriptHash()
+		// re-write existing contract variable, as we need it to be up-to-date during manifest update
+		contract = &state.Contract{
+			ID:       contract.ID,
+			Script:   script,
+			Manifest: contract.Manifest,
 		}
-		if err := ic.DAO.DeleteContractState(contract.ScriptHash()); err != nil {
-			return err
+		contract.Manifest.ABI.Hash = newHash
+		if err := ic.DAO.PutContractState(contract); err != nil {
+			return fmt.Errorf("failed to update script: %v", err)
+		}
+		if err := ic.DAO.DeleteContractState(oldHash); err != nil {
+			return fmt.Errorf("failed to update script: %v", err)
 		}
 	}
-	if !newcontract.HasStorage() {
-		siMap, err := ic.DAO.GetStorageItems(contract.ID)
+	// if manifest was provided, update the old contract manifest and check associated
+	// storage items if needed
+	if len(manifestBytes) > 0 {
+		var newManifest manifest.Manifest
+		err := newManifest.UnmarshalJSON(manifestBytes)
 		if err != nil {
-			return err
+			return fmt.Errorf("unable to retrieve manifest from stack: %v", err)
 		}
-		if len(siMap) != 0 {
-			return errors.New("old contract shouldn't have storage")
+		// we don't have to perform `GetContractState` one more time as it's already up-to-date
+		contract.Manifest = newManifest
+		if !contract.Manifest.IsValid(contract.ScriptHash()) {
+			return errors.New("failed to check contract script hash against new manifest")
+		}
+		if !contract.HasStorage() {
+			siMap, err := ic.DAO.GetStorageItems(contract.ID)
+			if err != nil {
+				return fmt.Errorf("failed to update manifest: %v", err)
+			}
+			if len(siMap) != 0 {
+				return errors.New("old contract shouldn't have storage")
+			}
+		}
+		if err := ic.DAO.PutContractState(contract); err != nil {
+			return fmt.Errorf("failed to update manifest: %v", err)
 		}
 	}
-	v.Estack().PushVal(stackitem.NewInterop(contract))
-	return contractDestroy(ic, v)
+	return nil
 }
 
 // runtimeSerialize serializes top stack item into a ByteArray.
@@ -152,3 +193,22 @@ func runtimeSerialize(_ *interop.Context, v *vm.VM) error {
 func runtimeDeserialize(_ *interop.Context, v *vm.VM) error {
 	return vm.RuntimeDeserialize(v)
 }
+
+// runtimeEncode encodes top stack item into a base64 string.
+func runtimeEncode(_ *interop.Context, v *vm.VM) error {
+	src := v.Estack().Pop().Bytes()
+	result := base64.StdEncoding.EncodeToString(src)
+	v.Estack().PushVal([]byte(result))
+	return nil
+}
+
+// runtimeDecode decodes top stack item from base64 string to byte array.
+func runtimeDecode(_ *interop.Context, v *vm.VM) error {
+	src := string(v.Estack().Pop().Bytes())
+	result, err := base64.StdEncoding.DecodeString(src)
+	if err != nil {
+		return err
+	}
+	v.Estack().PushVal(result)
+	return nil
+}

pkg/core/interop_neo_test.go

@@ -1,6 +1,7 @@
 package core
 
 import (
+	"encoding/base64"
 	"fmt"
 	"testing"
 
@@ -214,6 +215,39 @@ func TestECDSAVerify(t *testing.T) {
 	})
 }
 
+func TestRuntimeEncode(t *testing.T) {
+	str := []byte("my pretty string")
+	v, ic, bc := createVM(t)
+	defer bc.Close()
+
+	v.Estack().PushVal(str)
+	require.NoError(t, runtimeEncode(ic, v))
+
+	expected := []byte(base64.StdEncoding.EncodeToString(str))
+	actual := v.Estack().Pop().Bytes()
+	require.Equal(t, expected, actual)
+}
+
+func TestRuntimeDecode(t *testing.T) {
+	expected := []byte("my pretty string")
+	str := base64.StdEncoding.EncodeToString(expected)
+	v, ic, bc := createVM(t)
+	defer bc.Close()
+
+	t.Run("positive", func(t *testing.T) {
+		v.Estack().PushVal(str)
+		require.NoError(t, runtimeDecode(ic, v))
+
+		actual := v.Estack().Pop().Bytes()
+		require.Equal(t, expected, actual)
+	})
+
+	t.Run("error", func(t *testing.T) {
+		v.Estack().PushVal(str + "%")
+		require.Error(t, runtimeDecode(ic, v))
+	})
+}
+
 // Helper functions to create VM, InteropContext, TX, Account, Contract.
 
 func createVM(t *testing.T) (*vm.VM, *interop.Context, *Blockchain) {

pkg/core/interop_system.go

@@ -83,6 +83,20 @@ func bcGetBlock(ic *interop.Context, v *vm.VM) error {
 	return nil
 }
 
+// contractToStackItem converts state.Contract to stackitem.Item
+func contractToStackItem(cs *state.Contract) (stackitem.Item, error) {
+	manifest, err := cs.Manifest.MarshalJSON()
+	if err != nil {
+		return nil, err
+	}
+	return stackitem.NewArray([]stackitem.Item{
+		stackitem.NewByteArray(cs.Script),
+		stackitem.NewByteArray(manifest),
+		stackitem.NewBool(cs.HasStorage()),
+		stackitem.NewBool(cs.IsPayable()),
+	}), nil
+}
+
 // bcGetContract returns contract.
 func bcGetContract(ic *interop.Context, v *vm.VM) error {
 	hashbytes := v.Estack().Pop().Bytes()
@@ -92,9 +106,13 @@ func bcGetContract(ic *interop.Context, v *vm.VM) error {
 	}
 	cs, err := ic.DAO.GetContractState(hash)
 	if err != nil {
-		v.Estack().PushVal([]byte{})
+		v.Estack().PushVal(stackitem.Null{})
 	} else {
-		v.Estack().PushVal(stackitem.NewInterop(cs))
+		item, err := contractToStackItem(cs)
+		if err != nil {
+			return err
+		}
+		v.Estack().PushVal(item)
 	}
 	return nil
 }
@@ -155,12 +173,12 @@ func bcGetTransactionFromBlock(ic *interop.Context, v *vm.VM) error {
 	if err != nil {
 		return err
 	}
+	index := v.Estack().Pop().BigInt().Int64()
 	block, err := ic.DAO.GetBlock(hash)
 	if err != nil || !isTraceableBlock(ic, block.Index) {
 		v.Estack().PushVal(stackitem.Null{})
 		return nil
 	}
-	index := v.Estack().Pop().BigInt().Int64()
 	if index < 0 || index >= int64(len(block.Transactions)) {
 		return errors.New("wrong transaction index")
 	}
@@ -422,6 +440,9 @@ func contractCallEx(ic *interop.Context, v *vm.VM) error {
 	method := v.Estack().Pop().Item()
 	args := v.Estack().Pop().Item()
 	flags := smartcontract.CallFlag(int32(v.Estack().Pop().BigInt().Int64()))
+	if flags&^smartcontract.All != 0 {
+		return errors.New("call flags out of range")
+	}
 	return contractCallExInternal(ic, v, h, method, args, flags)
 }
 
@@ -483,8 +504,17 @@ func contractIsStandard(ic *interop.Context, v *vm.VM) error {
 	}
 	var result bool
 	cs, _ := ic.DAO.GetContractState(u)
-	if cs == nil || vm.IsStandardContract(cs.Script) {
-		result = true
+	if cs != nil {
+		result = vm.IsStandardContract(cs.Script)
+	} else {
+		if tx, ok := ic.Container.(*transaction.Transaction); ok {
+			for _, witness := range tx.Scripts {
+				if witness.ScriptHash() == u {
+					result = vm.IsStandardContract(witness.VerificationScript)
+					break
+				}
+			}
+		}
 	}
 	v.Estack().PushVal(result)
 	return nil
@@ -500,3 +530,9 @@ func contractCreateStandardAccount(ic *interop.Context, v *vm.VM) error {
 	v.Estack().PushVal(p.GetScriptHash().BytesBE())
 	return nil
 }
+
+// contractGetCallFlags returns current context calling flags.
+func contractGetCallFlags(_ *interop.Context, v *vm.VM) error {
+	v.Estack().PushVal(v.Context().GetCallFlags())
+	return nil
+}

pkg/core/interop_system_test.go

@@ -5,10 +5,14 @@ import (
 	"testing"
 
 	"github.com/nspcc-dev/dbft/crypto"
+	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"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/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
@@ -157,7 +161,35 @@ func TestContractIsStandard(t *testing.T) {
 	v, ic, chain := createVM(t)
 	defer chain.Close()
 
-	t.Run("True", func(t *testing.T) {
+	t.Run("contract not stored", func(t *testing.T) {
+		priv, err := keys.NewPrivateKey()
+		require.NoError(t, err)
+
+		pub := priv.PublicKey()
+		tx := transaction.New(netmode.TestNet, []byte{1, 2, 3}, 1)
+		tx.Scripts = []transaction.Witness{
+			{
+				InvocationScript:   []byte{1, 2, 3},
+				VerificationScript: pub.GetVerificationScript(),
+			},
+		}
+		ic.Container = tx
+
+		t.Run("true", func(t *testing.T) {
+			v.Estack().PushVal(pub.GetScriptHash().BytesBE())
+			require.NoError(t, contractIsStandard(ic, v))
+			require.True(t, v.Estack().Pop().Bool())
+		})
+
+		t.Run("false", func(t *testing.T) {
+			tx.Scripts[0].VerificationScript = []byte{9, 8, 7}
+			v.Estack().PushVal(pub.GetScriptHash().BytesBE())
+			require.NoError(t, contractIsStandard(ic, v))
+			require.False(t, v.Estack().Pop().Bool())
+		})
+	})
+
+	t.Run("contract stored, true", func(t *testing.T) {
 		priv, err := keys.NewPrivateKey()
 		require.NoError(t, err)
 
@@ -169,7 +201,7 @@ func TestContractIsStandard(t *testing.T) {
 		require.NoError(t, contractIsStandard(ic, v))
 		require.True(t, v.Estack().Pop().Bool())
 	})
-	t.Run("False", func(t *testing.T) {
+	t.Run("contract stored, false", func(t *testing.T) {
 		script := []byte{byte(opcode.PUSHT)}
 		require.NoError(t, ic.DAO.PutContractState(&state.Contract{ID: 24, Script: script}))
 
@@ -262,3 +294,300 @@ func TestRuntimeGetInvocationCounter(t *testing.T) {
 		require.EqualValues(t, 42, v.Estack().Pop().BigInt().Int64())
 	})
 }
+
+func TestBlockchainGetContractState(t *testing.T) {
+	v, cs, ic, bc := createVMAndContractState(t)
+	defer bc.Close()
+	require.NoError(t, ic.DAO.PutContractState(cs))
+
+	t.Run("positive", func(t *testing.T) {
+		v.Estack().PushVal(cs.ScriptHash().BytesBE())
+		require.NoError(t, bcGetContract(ic, v))
+
+		actual := v.Estack().Pop().Item()
+		compareContractStates(t, cs, actual)
+	})
+
+	t.Run("uncknown contract state", func(t *testing.T) {
+		v.Estack().PushVal(util.Uint160{1, 2, 3}.BytesBE())
+		require.NoError(t, bcGetContract(ic, v))
+
+		actual := v.Estack().Pop().Item()
+		require.Equal(t, stackitem.Null{}, actual)
+	})
+}
+
+func TestContractCreate(t *testing.T) {
+	v, cs, ic, bc := createVMAndContractState(t)
+	v.GasLimit = -1
+	defer bc.Close()
+
+	putArgsOnStack := func() {
+		manifest, err := cs.Manifest.MarshalJSON()
+		require.NoError(t, err)
+		v.Estack().PushVal(manifest)
+		v.Estack().PushVal(cs.Script)
+	}
+
+	t.Run("positive", func(t *testing.T) {
+		putArgsOnStack()
+
+		require.NoError(t, contractCreate(ic, v))
+		actual := v.Estack().Pop().Item()
+		compareContractStates(t, cs, actual)
+	})
+
+	t.Run("invalid scripthash", func(t *testing.T) {
+		cs.Script = append(cs.Script, 0x01)
+		putArgsOnStack()
+
+		require.Error(t, contractCreate(ic, v))
+	})
+
+	t.Run("contract already exists", func(t *testing.T) {
+		cs.Script = cs.Script[:len(cs.Script)-1]
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		putArgsOnStack()
+
+		require.Error(t, contractCreate(ic, v))
+	})
+}
+
+func compareContractStates(t *testing.T, expected *state.Contract, actual stackitem.Item) {
+	act, ok := actual.Value().([]stackitem.Item)
+	require.True(t, ok)
+
+	expectedManifest, err := expected.Manifest.MarshalJSON()
+	require.NoError(t, err)
+
+	require.Equal(t, 4, len(act))
+	require.Equal(t, expected.Script, act[0].Value().([]byte))
+	require.Equal(t, expectedManifest, act[1].Value().([]byte))
+	require.Equal(t, expected.HasStorage(), act[2].Bool())
+	require.Equal(t, expected.IsPayable(), act[3].Bool())
+}
+
+func TestContractUpdate(t *testing.T) {
+	v, cs, ic, bc := createVMAndContractState(t)
+	defer bc.Close()
+	v.GasLimit = -1
+
+	putArgsOnStack := func(script, manifest []byte) {
+		v.Estack().PushVal(manifest)
+		v.Estack().PushVal(script)
+	}
+
+	t.Run("no args", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		putArgsOnStack(nil, nil)
+		require.NoError(t, contractUpdate(ic, v))
+	})
+
+	t.Run("no contract", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, util.Uint160{8, 9, 7}, smartcontract.All)
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("too large script", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		putArgsOnStack(make([]byte, MaxContractScriptSize+1), nil)
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("too large manifest", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		putArgsOnStack(nil, make([]byte, manifest.MaxManifestSize+1))
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("gas limit exceeded", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.GasLimit = 0
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		putArgsOnStack([]byte{1}, []byte{2})
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("update script, the same script", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.GasLimit = -1
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		putArgsOnStack(cs.Script, nil)
+
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("update script, already exists", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		duplicateScript := []byte{byte(opcode.PUSHDATA4)}
+		require.NoError(t, ic.DAO.PutContractState(&state.Contract{
+			ID:     95,
+			Script: duplicateScript,
+			Manifest: manifest.Manifest{
+				ABI: manifest.ABI{
+					Hash: hash.Hash160(duplicateScript),
+				},
+			},
+		}))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		putArgsOnStack(duplicateScript, nil)
+
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("update script, positive", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		newScript := []byte{9, 8, 7, 6, 5}
+		putArgsOnStack(newScript, nil)
+
+		require.NoError(t, contractUpdate(ic, v))
+
+		// updated contract should have new scripthash
+		actual, err := ic.DAO.GetContractState(hash.Hash160(newScript))
+		require.NoError(t, err)
+		expected := &state.Contract{
+			ID:       cs.ID,
+			Script:   newScript,
+			Manifest: cs.Manifest,
+		}
+		expected.Manifest.ABI.Hash = hash.Hash160(newScript)
+		_ = expected.ScriptHash()
+		require.Equal(t, expected, actual)
+
+		// old contract should be deleted
+		_, err = ic.DAO.GetContractState(cs.ScriptHash())
+		require.Error(t, err)
+	})
+
+	t.Run("update manifest, bad manifest", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		putArgsOnStack(nil, []byte{1, 2, 3})
+
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("update manifest, bad contract hash", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		manifest := &manifest.Manifest{
+			ABI: manifest.ABI{
+				Hash: util.Uint160{4, 5, 6},
+			},
+		}
+		manifestBytes, err := manifest.MarshalJSON()
+		require.NoError(t, err)
+		putArgsOnStack(nil, manifestBytes)
+
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("update manifest, old contract shouldn't have storage", func(t *testing.T) {
+		cs.Manifest.Features |= smartcontract.HasStorage
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		require.NoError(t, ic.DAO.PutStorageItem(cs.ID, []byte("my_item"), &state.StorageItem{
+			Value:   []byte{1, 2, 3},
+			IsConst: false,
+		}))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		manifest := &manifest.Manifest{
+			ABI: manifest.ABI{
+				Hash: cs.ScriptHash(),
+			},
+		}
+		manifestBytes, err := manifest.MarshalJSON()
+		require.NoError(t, err)
+		putArgsOnStack(nil, manifestBytes)
+
+		require.Error(t, contractUpdate(ic, v))
+	})
+
+	t.Run("update manifest, positive", func(t *testing.T) {
+		cs.Manifest.Features = smartcontract.NoProperties
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		manifest := &manifest.Manifest{
+			ABI: manifest.ABI{
+				Hash: cs.ScriptHash(),
+				EntryPoint: manifest.Method{
+					Name: "Main",
+					Parameters: []manifest.Parameter{
+						manifest.NewParameter("NewParameter", smartcontract.IntegerType),
+					},
+					ReturnType: smartcontract.StringType,
+				},
+			},
+			Features: smartcontract.HasStorage,
+		}
+		manifestBytes, err := manifest.MarshalJSON()
+		require.NoError(t, err)
+		putArgsOnStack(nil, manifestBytes)
+
+		require.NoError(t, contractUpdate(ic, v))
+
+		// updated contract should have new scripthash
+		actual, err := ic.DAO.GetContractState(cs.ScriptHash())
+		expected := &state.Contract{
+			ID:       cs.ID,
+			Script:   cs.Script,
+			Manifest: *manifest,
+		}
+		_ = expected.ScriptHash()
+		require.Equal(t, expected, actual)
+	})
+
+	t.Run("update both script and manifest", func(t *testing.T) {
+		require.NoError(t, ic.DAO.PutContractState(cs))
+		v.LoadScriptWithHash([]byte{byte(opcode.RET)}, cs.ScriptHash(), smartcontract.All)
+		newScript := []byte{12, 13, 14}
+		newManifest := manifest.Manifest{
+			ABI: manifest.ABI{
+				Hash: hash.Hash160(newScript),
+				EntryPoint: manifest.Method{
+					Name: "Main",
+					Parameters: []manifest.Parameter{
+						manifest.NewParameter("VeryNewParameter", smartcontract.IntegerType),
+					},
+					ReturnType: smartcontract.StringType,
+				},
+			},
+			Features: smartcontract.HasStorage,
+		}
+		newManifestBytes, err := newManifest.MarshalJSON()
+		require.NoError(t, err)
+
+		putArgsOnStack(newScript, newManifestBytes)
+
+		require.NoError(t, contractUpdate(ic, v))
+
+		// updated contract should have new script and manifest
+		actual, err := ic.DAO.GetContractState(hash.Hash160(newScript))
+		require.NoError(t, err)
+		expected := &state.Contract{
+			ID:       cs.ID,
+			Script:   newScript,
+			Manifest: newManifest,
+		}
+		expected.Manifest.ABI.Hash = hash.Hash160(newScript)
+		_ = expected.ScriptHash()
+		require.Equal(t, expected, actual)
+
+		// old contract should be deleted
+		_, err = ic.DAO.GetContractState(cs.ScriptHash())
+		require.Error(t, err)
+	})
+}
+
+func TestContractGetCallFlags(t *testing.T) {
+	v, ic, bc := createVM(t)
+	defer bc.Close()
+
+	v.LoadScriptWithHash([]byte{byte(opcode.RET)}, util.Uint160{1, 2, 3}, smartcontract.All)
+	require.NoError(t, contractGetCallFlags(ic, v))
+	require.Equal(t, int64(smartcontract.All), v.Estack().Pop().Value().(*big.Int).Int64())
+}

pkg/core/interops.go

@@ -70,6 +70,8 @@ func getInteropFromSlice(ic *interop.Context, slice []interop.Function) func(uin
 
 // All lists are sorted, keep 'em this way, please.
 var systemInterops = []interop.Function{
+	{Name: "System.Binary.Base64Decode", Func: runtimeDecode, Price: 100000},
+	{Name: "System.Binary.Base64Encode", Func: runtimeEncode, Price: 100000},
 	{Name: "System.Binary.Deserialize", Func: runtimeDeserialize, Price: 500000},
 	{Name: "System.Binary.Serialize", Func: runtimeSerialize, Price: 100000},
 	{Name: "System.Blockchain.GetBlock", Func: bcGetBlock, Price: 2500000,
@@ -94,6 +96,7 @@ var systemInterops = []interop.Function{
 	{Name: "System.Contract.Destroy", Func: contractDestroy, Price: 1000000,
 		AllowedTriggers: trigger.Application, RequiredFlags: smartcontract.AllowModifyStates},
 	{Name: "System.Contract.IsStandard", Func: contractIsStandard, Price: 30000},
+	{Name: "System.Contract.GetCallFlags", Func: contractGetCallFlags, Price: 30000},
 	{Name: "System.Contract.Update", Func: contractUpdate, Price: 0,
 		AllowedTriggers: trigger.Application, RequiredFlags: smartcontract.AllowModifyStates},
 	{Name: "System.Enumerator.Concat", Func: enumerator.Concat, Price: 400},

pkg/interop/binary/binary.go

@@ -16,3 +16,15 @@ func Serialize(item interface{}) []byte {
 func Deserialize(b []byte) interface{} {
 	return nil
 }
+
+// Base64Encode encodes given byte slice into a base64 string and returns byte
+// representation of this string. It uses `System.Binary.Base64Encode` interop.
+func Base64Encode(b []byte) []byte {
+	return nil
+}
+
+// Base64Decode decodes given base64 string represented as a byte slice into
+// byte slice. It uses `System.Binary.Base64Decode` interop.
+func Base64Decode(b []byte) []byte {
+	return nil
+}

pkg/interop/blockchain/blockchain.go

@@ -3,9 +3,7 @@ Package blockchain provides functions to access various blockchain data.
 */
 package blockchain
 
-import (
-	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
-)
+import "github.com/nspcc-dev/neo-go/pkg/interop/contract"
 
 // Transaction represents a NEO transaction. It's similar to Transaction class
 // in Neo .net framework.

pkg/interop/contract/contract.go

@@ -4,10 +4,15 @@ Package contract provides functions to work with contracts.
 package contract
 
 // Contract represents a Neo contract and is used in interop functions. It's
-// an opaque data structure that you can manipulate with using functions from
+// a data structure that you can manipulate with using functions from
 // this package. It's similar in function to the Contract class in the Neo .net
 // framework.
-type Contract struct{}
+type Contract struct {
+	Script     []byte
+	Manifest   []byte
+	HasStorage bool
+	IsPayable  bool
+}
 
 // Create creates a new contract using a set of input parameters:
 //     script      contract's bytecode (limited in length by 1M)
@@ -23,8 +28,8 @@ func Create(script []byte, manifest []byte) Contract {
 // Create. The old contract will be deleted by this call, if it has any storage
 // associated it will be migrated to the new contract. New contract is returned.
 // This function uses `System.Contract.Update` syscall.
-func Update(script []byte, manifest []byte) Contract {
-	return Contract{}
+func Update(script []byte, manifest []byte) {
+	return
 }
 
 // Destroy deletes calling contract (the one that calls Destroy) from the
@@ -44,3 +49,9 @@ func IsStandard(h []byte) bool {
 func CreateStandardAccount(pub []byte) []byte {
 	return nil
 }
+
+// GetCallFlags returns calling flags which execution context was created with.
+// This function uses `System.Contract.GetCallFlags` syscall.
+func GetCallFlags() int64 {
+	return 0
+}

pkg/smartcontract/manifest/manifest.go

@@ -85,6 +85,20 @@ func (m *Manifest) CanCall(toCall *Manifest, method string) bool {
 	return false
 }
 
+// IsValid checks whether the given hash is the one specified in manifest and
+// verifies it against all the keys in manifest groups.
+func (m *Manifest) IsValid(hash util.Uint160) bool {
+	if m.ABI.Hash != hash {
+		return false
+	}
+	for _, g := range m.Groups {
+		if !g.IsValid(hash) {
+			return false
+		}
+	}
+	return true
+}
+
 // MarshalJSON implements json.Marshaler interface.
 func (m *Manifest) MarshalJSON() ([]byte, error) {
 	features := make(map[string]bool)

pkg/smartcontract/manifest/manifest_test.go

@@ -119,3 +119,50 @@ func TestPermission_IsAllowed(t *testing.T) {
 		require.False(t, perm.IsAllowed(manifest, "AAA"))
 	})
 }
+
+func TestIsValid(t *testing.T) {
+	contractHash := util.Uint160{1, 2, 3}
+	m := NewManifest(contractHash)
+
+	t.Run("valid, no groups", func(t *testing.T) {
+		require.True(t, m.IsValid(contractHash))
+	})
+
+	t.Run("invalid, no groups", func(t *testing.T) {
+		require.False(t, m.IsValid(util.Uint160{9, 8, 7}))
+	})
+
+	t.Run("with groups", func(t *testing.T) {
+		m.Groups = make([]Group, 3)
+		pks := make([]*keys.PrivateKey, 3)
+		for i := range pks {
+			pk, err := keys.NewPrivateKey()
+			require.NoError(t, err)
+			pks[i] = pk
+			m.Groups[i] = Group{
+				PublicKey: pk.PublicKey(),
+				Signature: pk.Sign(contractHash.BytesBE()),
+			}
+		}
+
+		t.Run("valid", func(t *testing.T) {
+			require.True(t, m.IsValid(contractHash))
+		})
+
+		t.Run("invalid, wrong contract hash", func(t *testing.T) {
+			require.False(t, m.IsValid(util.Uint160{4, 5, 6}))
+		})
+
+		t.Run("invalid, wrong group signature", func(t *testing.T) {
+			pk, err := keys.NewPrivateKey()
+			require.NoError(t, err)
+			m.Groups = append(m.Groups, Group{
+				PublicKey: pk.PublicKey(),
+				// actually, there shouldn't be such situation, as Signature is always the signature
+				// of the contract hash.
+				Signature: pk.Sign([]byte{1, 2, 3}),
+			})
+			require.False(t, m.IsValid(contractHash))
+		})
+	})
+}

pkg/smartcontract/manifest/method.go

@@ -4,8 +4,10 @@ import (
 	"encoding/hex"
 	"encoding/json"
 
+	"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"
+	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
 // Parameter represents smartcontract's parameter's definition.
@@ -60,6 +62,11 @@ func DefaultEntryPoint() *Method {
 	}
 }
 
+// IsValid checks whether group's signature corresponds to the given hash.
+func (g *Group) IsValid(h util.Uint160) bool {
+	return g.PublicKey.Verify(g.Signature, hash.Sha256(h.BytesBE()).BytesBE())
+}
+
 // MarshalJSON implements json.Marshaler interface.
 func (g *Group) MarshalJSON() ([]byte, error) {
 	aux := &groupAux{