package core import ( "errors" "fmt" "math" "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/smartcontract" "github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger" "github.com/nspcc-dev/neo-go/pkg/util" "github.com/nspcc-dev/neo-go/pkg/vm" "go.uber.org/zap" ) const ( // MaxStorageKeyLen is the maximum length of a key for storage items. MaxStorageKeyLen = 1024 ) // 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 } // 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 { v.Estack().PushVal([]byte{}) } else { v.Estack().PushVal(vm.NewInteropItem(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(vm.NewInteropItem(cs)) } return nil } // bcGetHeader returns block header. func bcGetHeader(ic *interop.Context, v *vm.VM) error { hash, err := getBlockHashFromElement(ic.Chain, v.Estack().Pop()) if err != nil { return err } header, err := ic.Chain.GetHeader(hash) if err != nil { v.Estack().PushVal([]byte{}) } else { v.Estack().PushVal(vm.NewInteropItem(header)) } 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) } // bcGetTransaction returns transaction. func bcGetTransaction(ic *interop.Context, v *vm.VM) error { tx, _, err := getTransactionAndHeight(ic.DAO, v) if err != nil { return err } v.Estack().PushVal(vm.NewInteropItem(tx)) return nil } // bcGetTransactionHeight returns transaction height. func bcGetTransactionHeight(ic *interop.Context, v *vm.VM) error { _, h, err := getTransactionAndHeight(ic.DAO, v) if err != nil { return err } v.Estack().PushVal(h) return nil } // popHeaderFromVM returns pointer to Header or error. It's main feature is // proper treatment of Block structure, because C# code implicitly assumes // that header APIs can also operate on blocks. func popHeaderFromVM(v *vm.VM) (*block.Header, error) { iface := v.Estack().Pop().Value() header, ok := iface.(*block.Header) if !ok { block, ok := iface.(*block.Block) if !ok { return nil, errors.New("value is not a header or block") } return block.Header(), nil } return header, nil } // headerGetIndex returns block index from the header. func headerGetIndex(ic *interop.Context, v *vm.VM) error { header, err := popHeaderFromVM(v) if err != nil { return err } v.Estack().PushVal(header.Index) return nil } // headerGetHash returns header hash of the passed header. func headerGetHash(ic *interop.Context, v *vm.VM) error { header, err := popHeaderFromVM(v) if err != nil { return err } v.Estack().PushVal(header.Hash().BytesBE()) return nil } // headerGetPrevHash returns previous header hash of the passed header. func headerGetPrevHash(ic *interop.Context, v *vm.VM) error { header, err := popHeaderFromVM(v) if err != nil { return err } v.Estack().PushVal(header.PrevHash.BytesBE()) return nil } // headerGetTimestamp returns timestamp of the passed header. func headerGetTimestamp(ic *interop.Context, v *vm.VM) error { header, err := popHeaderFromVM(v) if err != nil { return err } v.Estack().PushVal(header.Timestamp) return nil } // blockGetTransactionCount returns transactions count in the given block. func blockGetTransactionCount(ic *interop.Context, v *vm.VM) error { blockInterface := v.Estack().Pop().Value() block, ok := blockInterface.(*block.Block) if !ok { return errors.New("value is not a block") } v.Estack().PushVal(len(block.Transactions)) return nil } // blockGetTransactions returns transactions from the given block. func blockGetTransactions(ic *interop.Context, v *vm.VM) error { blockInterface := v.Estack().Pop().Value() block, ok := blockInterface.(*block.Block) if !ok { return errors.New("value is not a block") } if len(block.Transactions) > vm.MaxArraySize { return errors.New("too many transactions") } txes := make([]vm.StackItem, 0, len(block.Transactions)) for _, tx := range block.Transactions { txes = append(txes, vm.NewInteropItem(tx)) } v.Estack().PushVal(txes) return nil } // blockGetTransaction returns transaction with the given number from the given // block. func blockGetTransaction(ic *interop.Context, v *vm.VM) error { blockInterface := v.Estack().Pop().Value() block, ok := blockInterface.(*block.Block) if !ok { return errors.New("value is not a block") } 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(vm.NewInteropItem(tx)) return nil } // txGetHash returns transaction's hash. func txGetHash(ic *interop.Context, v *vm.VM) error { txInterface := v.Estack().Pop().Value() tx, ok := txInterface.(*transaction.Transaction) if !ok { return errors.New("value is not a transaction") } v.Estack().PushVal(tx.Hash().BytesBE()) return nil } // engineGetScriptContainer returns transaction that contains the script being // run. func engineGetScriptContainer(ic *interop.Context, v *vm.VM) error { v.Estack().PushVal(vm.NewInteropItem(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 := vm.SerializeItem(item) if err != nil { item = vm.NewByteArrayItem([]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 { if ic.Trigger != trigger.Application && ic.Trigger != trigger.ApplicationR { return errors.New("can't delete when the trigger is not application") } 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(vm.NewInteropItem(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(vm.NewInteropItem(sc)) return nil } func putWithContextAndFlags(ic *interop.Context, stc *StorageContext, key []byte, value []byte, isConst bool) error { if ic.Trigger != trigger.Application && ic.Trigger != trigger.ApplicationR { return errors.New("can't delete when the trigger is not application") } 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") } 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, 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(vm.NewInteropItem(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 vm.StackItem, args vm.StackItem, _ smartcontract.CallFlag) error { u, err := util.Uint160DecodeBytesBE(h) if err != nil { return errors.New("invalid contract hash") } script, _ := ic.GetContract(u) if script == nil { return errors.New("contract not found") } // TODO perform flags checking after #923 v.LoadScript(script) v.Estack().PushVal(args) v.Estack().PushVal(method) return nil } // contractDestroy destroys a contract. func contractDestroy(ic *interop.Context, v *vm.VM) error { if ic.Trigger != trigger.Application { return errors.New("can't destroy contract when not triggered by application") } 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 } // contractGetStorageContext retrieves StorageContext of a contract. func contractGetStorageContext(ic *interop.Context, v *vm.VM) error { csInterface := v.Estack().Pop().Value() cs, ok := csInterface.(*state.Contract) if !ok { return fmt.Errorf("%T is not a contract state", cs) } contractState, err := ic.DAO.GetContractState(cs.ScriptHash()) if contractState == nil || err != nil { return fmt.Errorf("contract was not created in this transaction") } stc := &StorageContext{ ScriptHash: cs.ScriptHash(), } v.Estack().PushVal(vm.NewInteropItem(stc)) return nil }