package core import ( "errors" "fmt" "math" "math/big" "github.com/nspcc-dev/neo-go/pkg/core/block" "github.com/nspcc-dev/neo-go/pkg/core/blockchainer" "github.com/nspcc-dev/neo-go/pkg/core/dao" "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/core/transaction" "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" "github.com/nspcc-dev/neo-go/pkg/vm" "github.com/nspcc-dev/neo-go/pkg/vm/stackitem" "go.uber.org/zap" ) const ( // MaxStorageKeyLen is the maximum length of a key for storage items. MaxStorageKeyLen = 1024 // MaxTraceableBlocks is the maximum number of blocks before current chain // height we're able to give information about. MaxTraceableBlocks = transaction.MaxValidUntilBlockIncrement ) // StorageContext contains storing script hash and read/write flag, it's used as // a context for storage manipulation functions. type StorageContext struct { ScriptHash util.Uint160 ReadOnly bool } // getBlockHashFromElement converts given vm.Element to block hash using given // Blockchainer if needed. Interop functions accept both block numbers and // block hashes as parameters, thus this function is needed. func getBlockHashFromElement(bc blockchainer.Blockchainer, element *vm.Element) (util.Uint256, error) { var hash util.Uint256 hashbytes := element.Bytes() if len(hashbytes) <= 5 { hashint := element.BigInt().Int64() if hashint < 0 || hashint > math.MaxUint32 { return hash, errors.New("bad block index") } hash = bc.GetHeaderHash(int(hashint)) } else { return util.Uint256DecodeBytesBE(hashbytes) } return hash, nil } // blockToStackItem converts block.Block to stackitem.Item func blockToStackItem(b *block.Block) stackitem.Item { return stackitem.NewArray([]stackitem.Item{ stackitem.NewByteArray(b.Hash().BytesBE()), stackitem.NewBigInteger(big.NewInt(int64(b.Version))), stackitem.NewByteArray(b.PrevHash.BytesBE()), stackitem.NewByteArray(b.MerkleRoot.BytesBE()), stackitem.NewBigInteger(big.NewInt(int64(b.Timestamp))), stackitem.NewBigInteger(big.NewInt(int64(b.Index))), stackitem.NewByteArray(b.NextConsensus.BytesBE()), stackitem.NewBigInteger(big.NewInt(int64(len(b.Transactions)))), }) } // bcGetBlock returns current block. func bcGetBlock(ic *interop.Context, v *vm.VM) error { hash, err := getBlockHashFromElement(ic.Chain, v.Estack().Pop()) if err != nil { return err } block, err := ic.Chain.GetBlock(hash) if err != nil || !isTraceableBlock(ic, block.Index) { v.Estack().PushVal(stackitem.Null{}) } else { v.Estack().PushVal(blockToStackItem(block)) } return nil } // bcGetContract returns contract. func bcGetContract(ic *interop.Context, v *vm.VM) error { hashbytes := v.Estack().Pop().Bytes() hash, err := util.Uint160DecodeBytesBE(hashbytes) if err != nil { return err } cs, err := ic.DAO.GetContractState(hash) if err != nil { v.Estack().PushVal([]byte{}) } else { v.Estack().PushVal(stackitem.NewInterop(cs)) } return nil } // bcGetHeight returns blockchain height. func bcGetHeight(ic *interop.Context, v *vm.VM) error { v.Estack().PushVal(ic.Chain.BlockHeight()) return nil } // getTransactionAndHeight gets parameter from the vm evaluation stack and // returns transaction and its height if it's present in the blockchain. func getTransactionAndHeight(cd *dao.Cached, v *vm.VM) (*transaction.Transaction, uint32, error) { hashbytes := v.Estack().Pop().Bytes() hash, err := util.Uint256DecodeBytesBE(hashbytes) if err != nil { return nil, 0, err } return cd.GetTransaction(hash) } // isTraceableBlock defines whether we're able to give information about // the block with index specified. func isTraceableBlock(ic *interop.Context, index uint32) bool { height := ic.Chain.BlockHeight() return index <= height && index+MaxTraceableBlocks > height } // transactionToStackItem converts transaction.Transaction to stackitem.Item func transactionToStackItem(t *transaction.Transaction) stackitem.Item { return stackitem.NewArray([]stackitem.Item{ stackitem.NewByteArray(t.Hash().BytesBE()), stackitem.NewBigInteger(big.NewInt(int64(t.Version))), stackitem.NewBigInteger(big.NewInt(int64(t.Nonce))), stackitem.NewByteArray(t.Sender.BytesBE()), stackitem.NewBigInteger(big.NewInt(int64(t.SystemFee))), stackitem.NewBigInteger(big.NewInt(int64(t.NetworkFee))), stackitem.NewBigInteger(big.NewInt(int64(t.ValidUntilBlock))), stackitem.NewByteArray(t.Script), }) } // bcGetTransaction returns transaction. func bcGetTransaction(ic *interop.Context, v *vm.VM) error { tx, h, err := getTransactionAndHeight(ic.DAO, v) if err != nil || !isTraceableBlock(ic, h) { v.Estack().PushVal(stackitem.Null{}) return nil } v.Estack().PushVal(transactionToStackItem(tx)) return nil } // bcGetTransactionFromBlock returns transaction with the given index from the // block with height or hash specified. func bcGetTransactionFromBlock(ic *interop.Context, v *vm.VM) error { hash, err := getBlockHashFromElement(ic.Chain, v.Estack().Pop()) if err != nil { return err } 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") } tx := block.Transactions[index] v.Estack().PushVal(tx.Hash().BytesBE()) return nil } // bcGetTransactionHeight returns transaction height. func bcGetTransactionHeight(ic *interop.Context, v *vm.VM) error { _, h, err := getTransactionAndHeight(ic.DAO, v) if err != nil || !isTraceableBlock(ic, h) { v.Estack().PushVal(-1) return nil } v.Estack().PushVal(h) return nil } // engineGetScriptContainer returns transaction that contains the script being // run. func engineGetScriptContainer(ic *interop.Context, v *vm.VM) error { v.Estack().PushVal(stackitem.NewInterop(ic.Container)) return nil } // engineGetExecutingScriptHash returns executing script hash. func engineGetExecutingScriptHash(ic *interop.Context, v *vm.VM) error { return v.PushContextScriptHash(0) } // engineGetCallingScriptHash returns calling script hash. func engineGetCallingScriptHash(ic *interop.Context, v *vm.VM) error { return v.PushContextScriptHash(1) } // engineGetEntryScriptHash returns entry script hash. func engineGetEntryScriptHash(ic *interop.Context, v *vm.VM) error { return v.PushContextScriptHash(v.Istack().Len() - 1) } // runtimePlatform returns the name of the platform. func runtimePlatform(ic *interop.Context, v *vm.VM) error { v.Estack().PushVal([]byte("NEO")) return nil } // runtimeGetTrigger returns the script trigger. func runtimeGetTrigger(ic *interop.Context, v *vm.VM) error { v.Estack().PushVal(byte(ic.Trigger)) return nil } // runtimeNotify should pass stack item to the notify plugin to handle it, but // in neo-go the only meaningful thing to do here is to log. func runtimeNotify(ic *interop.Context, v *vm.VM) error { // It can be just about anything. e := v.Estack().Pop() item := e.Item() // But it has to be serializable, otherwise we either have some broken // (recursive) structure inside or an interop item that can't be used // outside of the interop subsystem anyway. I'd probably fail transactions // that emit such broken notifications, but that might break compatibility // with testnet/mainnet, so we're replacing these with error messages. _, err := stackitem.SerializeItem(item) if err != nil { item = stackitem.NewByteArray([]byte(fmt.Sprintf("bad notification: %v", err))) } ne := state.NotificationEvent{ScriptHash: v.GetCurrentScriptHash(), Item: item} ic.Notifications = append(ic.Notifications, ne) return nil } // runtimeLog logs the message passed. func runtimeLog(ic *interop.Context, v *vm.VM) error { msg := fmt.Sprintf("%q", v.Estack().Pop().Bytes()) ic.Log.Info("runtime log", zap.Stringer("script", v.GetCurrentScriptHash()), zap.String("logs", msg)) return nil } // runtimeGetTime returns timestamp of the block being verified, or the latest // one in the blockchain if no block is given to Context. func runtimeGetTime(ic *interop.Context, v *vm.VM) error { var header *block.Header if ic.Block == nil { var err error header, err = ic.Chain.GetHeader(ic.Chain.CurrentBlockHash()) if err != nil { return err } } else { header = ic.Block.Header() } v.Estack().PushVal(header.Timestamp) return nil } func checkStorageContext(ic *interop.Context, stc *StorageContext) error { contract, err := ic.DAO.GetContractState(stc.ScriptHash) if err != nil { return errors.New("no contract found") } if !contract.HasStorage() { return fmt.Errorf("contract %s can't use storage", stc.ScriptHash) } return nil } // storageDelete deletes stored key-value pair. func storageDelete(ic *interop.Context, v *vm.VM) error { stcInterface := v.Estack().Pop().Value() stc, ok := stcInterface.(*StorageContext) if !ok { return fmt.Errorf("%T is not a StorageContext", stcInterface) } if stc.ReadOnly { return errors.New("StorageContext is read only") } err := checkStorageContext(ic, stc) if err != nil { return err } key := v.Estack().Pop().Bytes() si := ic.DAO.GetStorageItem(stc.ScriptHash, key) if si != nil && si.IsConst { return errors.New("storage item is constant") } return ic.DAO.DeleteStorageItem(stc.ScriptHash, key) } // storageGet returns stored key-value pair. func storageGet(ic *interop.Context, v *vm.VM) error { stcInterface := v.Estack().Pop().Value() stc, ok := stcInterface.(*StorageContext) if !ok { return fmt.Errorf("%T is not a StorageContext", stcInterface) } err := checkStorageContext(ic, stc) if err != nil { return err } key := v.Estack().Pop().Bytes() si := ic.DAO.GetStorageItem(stc.ScriptHash, key) if si != nil && si.Value != nil { v.Estack().PushVal(si.Value) } else { v.Estack().PushVal([]byte{}) } return nil } // storageGetContext returns storage context (scripthash). func storageGetContext(ic *interop.Context, v *vm.VM) error { sc := &StorageContext{ ScriptHash: v.GetCurrentScriptHash(), ReadOnly: false, } v.Estack().PushVal(stackitem.NewInterop(sc)) return nil } // storageGetReadOnlyContext returns read-only context (scripthash). func storageGetReadOnlyContext(ic *interop.Context, v *vm.VM) error { sc := &StorageContext{ ScriptHash: v.GetCurrentScriptHash(), ReadOnly: true, } v.Estack().PushVal(stackitem.NewInterop(sc)) return nil } func putWithContextAndFlags(ic *interop.Context, v *vm.VM, stc *StorageContext, key []byte, value []byte, isConst bool) error { if len(key) > MaxStorageKeyLen { return errors.New("key is too big") } if stc.ReadOnly { return errors.New("StorageContext is read only") } err := checkStorageContext(ic, stc) if err != nil { return err } si := ic.DAO.GetStorageItem(stc.ScriptHash, key) if si == nil { si = &state.StorageItem{} } if si.IsConst { return errors.New("storage item exists and is read-only") } sizeInc := 1 if len(value) > len(si.Value) { sizeInc = len(value) - len(si.Value) } if !v.AddGas(util.Fixed8(sizeInc) * StoragePrice) { return errGasLimitExceeded } si.Value = value si.IsConst = isConst return ic.DAO.PutStorageItem(stc.ScriptHash, key, si) } // storagePutInternal is a unified implementation of storagePut and storagePutEx. func storagePutInternal(ic *interop.Context, v *vm.VM, getFlag bool) error { stcInterface := v.Estack().Pop().Value() stc, ok := stcInterface.(*StorageContext) if !ok { return fmt.Errorf("%T is not a StorageContext", stcInterface) } key := v.Estack().Pop().Bytes() value := v.Estack().Pop().Bytes() var flag int if getFlag { flag = int(v.Estack().Pop().BigInt().Int64()) } return putWithContextAndFlags(ic, v, stc, key, value, flag == 1) } // storagePut puts key-value pair into the storage. func storagePut(ic *interop.Context, v *vm.VM) error { return storagePutInternal(ic, v, false) } // storagePutEx puts key-value pair with given flags into the storage. func storagePutEx(ic *interop.Context, v *vm.VM) error { return storagePutInternal(ic, v, true) } // storageContextAsReadOnly sets given context to read-only mode. func storageContextAsReadOnly(ic *interop.Context, v *vm.VM) error { stcInterface := v.Estack().Pop().Value() stc, ok := stcInterface.(*StorageContext) if !ok { return fmt.Errorf("%T is not a StorageContext", stcInterface) } if !stc.ReadOnly { stx := &StorageContext{ ScriptHash: stc.ScriptHash, ReadOnly: true, } stc = stx } v.Estack().PushVal(stackitem.NewInterop(stc)) return nil } // contractCall calls a contract. func contractCall(ic *interop.Context, v *vm.VM) error { h := v.Estack().Pop().Bytes() method := v.Estack().Pop().Item() args := v.Estack().Pop().Item() return contractCallExInternal(ic, v, h, method, args, smartcontract.All) } // contractCallEx calls a contract with flags. func contractCallEx(ic *interop.Context, v *vm.VM) error { h := v.Estack().Pop().Bytes() method := v.Estack().Pop().Item() args := v.Estack().Pop().Item() flags := smartcontract.CallFlag(int32(v.Estack().Pop().BigInt().Int64())) return contractCallExInternal(ic, v, h, method, args, flags) } func contractCallExInternal(ic *interop.Context, v *vm.VM, h []byte, method stackitem.Item, args stackitem.Item, f smartcontract.CallFlag) error { u, err := util.Uint160DecodeBytesBE(h) if err != nil { return errors.New("invalid contract hash") } cs, err := ic.DAO.GetContractState(u) if err != nil { return errors.New("contract not found") } bs, err := method.TryBytes() if err != nil { return err } curr, err := ic.DAO.GetContractState(v.GetCurrentScriptHash()) if err == nil { if !curr.Manifest.CanCall(&cs.Manifest, string(bs)) { return errors.New("disallowed method call") } } ic.Invocations[u]++ v.LoadScriptWithHash(cs.Script, u, v.Context().GetCallFlags()&f) v.Estack().PushVal(args) v.Estack().PushVal(method) return nil } // contractDestroy destroys a contract. func contractDestroy(ic *interop.Context, v *vm.VM) error { hash := v.GetCurrentScriptHash() cs, err := ic.DAO.GetContractState(hash) if err != nil { return nil } err = ic.DAO.DeleteContractState(hash) if err != nil { return err } if cs.HasStorage() { siMap, err := ic.DAO.GetStorageItems(hash) if err != nil { return err } for k := range siMap { _ = ic.DAO.DeleteStorageItem(hash, []byte(k)) } } return nil } // contractIsStandard checks if contract is standard (sig or multisig) contract. func contractIsStandard(ic *interop.Context, v *vm.VM) error { h := v.Estack().Pop().Bytes() u, err := util.Uint160DecodeBytesBE(h) if err != nil { return err } var result bool cs, _ := ic.DAO.GetContractState(u) if cs == nil || vm.IsStandardContract(cs.Script) { result = true } v.Estack().PushVal(result) return nil } // contractCreateStandardAccount calculates contract scripthash for a given public key. func contractCreateStandardAccount(ic *interop.Context, v *vm.VM) error { h := v.Estack().Pop().Bytes() p, err := keys.NewPublicKeyFromBytes(h) if err != nil { return err } v.Estack().PushVal(p.GetScriptHash().BytesBE()) return nil }