diff --git a/pkg/core/interop/contract/call.go b/pkg/core/interop/contract/call.go index 93124edea..2f84657d5 100644 --- a/pkg/core/interop/contract/call.go +++ b/pkg/core/interop/contract/call.go @@ -124,7 +124,7 @@ func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contra if wrapped { ic.DAO = ic.DAO.GetPrivate() } - onUnload := func(ctx *vm.Context, commit bool) error { + onUnload := func(v *vm.VM, ctx *vm.Context, commit bool) error { if wrapped { if commit { _, err := ic.DAO.Persist() @@ -136,17 +136,12 @@ func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contra } ic.DAO = baseDAO } - if isDynamic && commit { - eLen := ctx.Estack().Len() - if eLen == 0 && ctx.NumOfReturnVals() == 0 { // No return value and none expected. - ic.VM.Context().Estack().PushItem(stackitem.Null{}) // Must use current context stack. - } else if eLen > 1 { // 1 or -1 (all) retrun values expected, but only one can be returned. - return errors.New("multiple return values in a cross-contract call") - } // All other rvcount/stack length mismatches are checked by the VM. - } if callFromNative && !commit { return fmt.Errorf("unhandled exception") } + if isDynamic { + return vm.DynamicOnUnload(v, ctx, commit) + } return nil } ic.VM.LoadNEFMethod(&cs.NEF, caller, cs.Hash, f, diff --git a/pkg/core/interop/interopnames/names.go b/pkg/core/interop/interopnames/names.go index bdb3b93d1..ccc2e12ed 100644 --- a/pkg/core/interop/interopnames/names.go +++ b/pkg/core/interop/interopnames/names.go @@ -27,6 +27,7 @@ const ( SystemRuntimeGetScriptContainer = "System.Runtime.GetScriptContainer" SystemRuntimeGetTime = "System.Runtime.GetTime" SystemRuntimeGetTrigger = "System.Runtime.GetTrigger" + SystemRuntimeLoadScript = "System.Runtime.LoadScript" SystemRuntimeLog = "System.Runtime.Log" SystemRuntimeNotify = "System.Runtime.Notify" SystemRuntimePlatform = "System.Runtime.Platform" diff --git a/pkg/core/interop/runtime/engine.go b/pkg/core/interop/runtime/engine.go index de9055e29..a2daa48d9 100644 --- a/pkg/core/interop/runtime/engine.go +++ b/pkg/core/interop/runtime/engine.go @@ -6,6 +6,8 @@ import ( "math/big" "github.com/nspcc-dev/neo-go/pkg/core/interop" + "github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag" + "github.com/nspcc-dev/neo-go/pkg/vm" "github.com/nspcc-dev/neo-go/pkg/vm/stackitem" "go.uber.org/zap" ) @@ -105,6 +107,27 @@ func Notify(ic *interop.Context) error { return nil } +// LoadScript takes a script and arguments from the stack and loads it into the VM. +func LoadScript(ic *interop.Context) error { + script := ic.VM.Estack().Pop().Bytes() + fs := callflag.CallFlag(int32(ic.VM.Estack().Pop().BigInt().Int64())) + if fs&^callflag.All != 0 { + return errors.New("call flags out of range") + } + args := ic.VM.Estack().Pop().Array() + err := vm.IsScriptCorrect(script, nil) + if err != nil { + return fmt.Errorf("invalid script: %w", err) + } + fs = ic.VM.Context().GetCallFlags() & callflag.ReadOnly & fs + ic.VM.LoadDynamicScript(script, fs) + + for e, i := ic.VM.Estack(), len(args)-1; i >= 0; i-- { + e.PushItem(args[i]) + } + return nil +} + // Log logs the message passed. func Log(ic *interop.Context) error { state := ic.VM.Estack().Pop().String() diff --git a/pkg/core/interop/runtime/ext_test.go b/pkg/core/interop/runtime/ext_test.go index 0b724379b..d423ee701 100644 --- a/pkg/core/interop/runtime/ext_test.go +++ b/pkg/core/interop/runtime/ext_test.go @@ -80,6 +80,28 @@ func loadScriptWithHashAndFlags(ic *interop.Context, script []byte, hash util.Ui ic.VM.GasLimit = -1 } +func wrapDynamicScript(t *testing.T, script []byte, flags callflag.CallFlag, args ...interface{}) []byte { + b := io.NewBufBinWriter() + + // Params. + emit.Array(b.BinWriter, args...) + emit.Int(b.BinWriter, int64(flags)) + emit.Bytes(b.BinWriter, script) + + // Wrapped syscall. + emit.Instruction(b.BinWriter, opcode.TRY, []byte{3 + 5 + 2, 0}) // 3 + emit.Syscall(b.BinWriter, interopnames.SystemRuntimeLoadScript) // 5 + emit.Instruction(b.BinWriter, opcode.ENDTRY, []byte{1 + 11 + 2}) // 2 + + // Catch block + emit.Opcodes(b.BinWriter, opcode.DROP) + emit.String(b.BinWriter, "exception") // 1 + 1 + 9 == 11 bytes + emit.Opcodes(b.BinWriter, opcode.RET) + + require.NoError(t, b.Err) + return b.Bytes() +} + func getDeployedInternal(t *testing.T) (*neotest.Executor, neotest.Signer, *core.Blockchain, *state.Contract) { bc, acc := chain.NewSingle(t) e := neotest.NewExecutor(t, bc, acc, acc) @@ -377,6 +399,66 @@ func TestCheckWitness(t *testing.T) { }) } +func TestLoadScript(t *testing.T) { + bc, acc := chain.NewSingle(t) + e := neotest.NewExecutor(t, bc, acc, acc) + + t.Run("no ret val", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{byte(opcode.RET)}, callflag.All) + e.InvokeScriptCheckHALT(t, script, []neotest.Signer{acc}, stackitem.Null{}) + }) + t.Run("empty script", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{}, callflag.All) + e.InvokeScriptCheckHALT(t, script, []neotest.Signer{acc}, stackitem.Null{}) + }) + t.Run("bad script", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{0xff}, callflag.All) + e.InvokeScriptCheckFAULT(t, script, []neotest.Signer{acc}, "invalid script") + }) + t.Run("ret val, no params", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{byte(opcode.PUSH1)}, callflag.All) + e.InvokeScriptCheckHALT(t, script, []neotest.Signer{acc}, stackitem.Make(1)) + }) + t.Run("ret val with params", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{byte(opcode.MUL)}, callflag.All, 2, 2) + e.InvokeScriptCheckHALT(t, script, []neotest.Signer{acc}, stackitem.Make(4)) + }) + t.Run("two retrun values", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{byte(opcode.PUSH1), byte(opcode.PUSH1)}, callflag.All, 2, 2) + e.InvokeScriptCheckFAULT(t, script, []neotest.Signer{acc}, "multiple return values in a cross-contract call") + }) + t.Run("invalid flags", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{byte(opcode.MUL)}, callflag.CallFlag(0xff), 2, 2) + e.InvokeScriptCheckFAULT(t, script, []neotest.Signer{acc}, "call flags out of range") + }) + t.Run("abort", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{byte(opcode.ABORT)}, callflag.All) + e.InvokeScriptCheckFAULT(t, script, []neotest.Signer{acc}, "ABORT") + }) + t.Run("internal call", func(t *testing.T) { + script, err := smartcontract.CreateCallScript(e.NativeHash(t, nativenames.Gas), "decimals") + require.NoError(t, err) + script = wrapDynamicScript(t, script, callflag.ReadOnly) + e.InvokeScriptCheckHALT(t, script, []neotest.Signer{acc}, stackitem.Make(8)) + }) + t.Run("forbidden internal call", func(t *testing.T) { + script, err := smartcontract.CreateCallScript(e.NativeHash(t, nativenames.Neo), "decimals") + require.NoError(t, err) + script = wrapDynamicScript(t, script, callflag.ReadStates) + e.InvokeScriptCheckFAULT(t, script, []neotest.Signer{acc}, "missing call flags") + }) + t.Run("internal state-changing call", func(t *testing.T) { + script, err := smartcontract.CreateCallScript(e.NativeHash(t, nativenames.Neo), "transfer", acc.ScriptHash(), acc.ScriptHash(), 1, nil) + require.NoError(t, err) + script = wrapDynamicScript(t, script, callflag.All) + e.InvokeScriptCheckFAULT(t, script, []neotest.Signer{acc}, "missing call flags") + }) + t.Run("exception", func(t *testing.T) { + script := wrapDynamicScript(t, []byte{byte(opcode.PUSH1), byte(opcode.THROW)}, callflag.ReadOnly) + e.InvokeScriptCheckHALT(t, script, []neotest.Signer{acc}, stackitem.Make("exception")) + }) +} + func TestGasLeft(t *testing.T) { const runtimeGasLeftPrice = 1 << 4 diff --git a/pkg/core/interops.go b/pkg/core/interops.go index 5612a4e20..88de802ba 100644 --- a/pkg/core/interops.go +++ b/pkg/core/interops.go @@ -58,6 +58,8 @@ var systemInterops = []interop.Function{ {Name: interopnames.SystemRuntimeGetScriptContainer, Func: runtime.GetScriptContainer, Price: 1 << 3}, {Name: interopnames.SystemRuntimeGetTime, Func: runtime.GetTime, Price: 1 << 3, RequiredFlags: callflag.ReadStates}, {Name: interopnames.SystemRuntimeGetTrigger, Func: runtime.GetTrigger, Price: 1 << 3}, + {Name: interopnames.SystemRuntimeLoadScript, Func: runtime.LoadScript, Price: 1 << 15, RequiredFlags: callflag.AllowCall, + ParamCount: 3}, {Name: interopnames.SystemRuntimeLog, Func: runtime.Log, Price: 1 << 15, RequiredFlags: callflag.AllowNotify, ParamCount: 1}, {Name: interopnames.SystemRuntimeNotify, Func: runtime.Notify, Price: 1 << 15, RequiredFlags: callflag.AllowNotify, diff --git a/pkg/vm/context.go b/pkg/vm/context.go index b85ba2f75..95d693296 100644 --- a/pkg/vm/context.go +++ b/pkg/vm/context.go @@ -79,10 +79,14 @@ type contextAux struct { } // ContextUnloadCallback is a callback method used on context unloading from istack. -type ContextUnloadCallback func(ctx *Context, commit bool) error +type ContextUnloadCallback func(v *VM, ctx *Context, commit bool) error var errNoInstParam = errors.New("failed to read instruction parameter") +// ErrMultiRet is returned when caller does not expect multiple return values +// from callee. +var ErrMultiRet = errors.New("multiple return values in a cross-contract call") + // NewContext returns a new Context object. func NewContext(b []byte) *Context { return NewContextWithParams(b, -1, 0) @@ -331,3 +335,18 @@ func (c *Context) MarshalJSON() ([]byte, error) { } return json.Marshal(aux) } + +// DynamicOnUnload implements OnUnload script for dynamic calls, if no exception +// has occurred it checks that the context has exactly 0 (in which case a `Null` +// is pushed) or 1 returned value. +func DynamicOnUnload(v *VM, ctx *Context, commit bool) error { + if commit { + eLen := ctx.Estack().Len() + if eLen == 0 { // No return value, add one. + v.Context().Estack().PushItem(stackitem.Null{}) // Must use current context stack. + } else if eLen > 1 { // Only one can be returned. + return ErrMultiRet + } // One value returned, it's OK. + } + return nil +} diff --git a/pkg/vm/vm.go b/pkg/vm/vm.go index ef8c41351..dcb8b2a49 100644 --- a/pkg/vm/vm.go +++ b/pkg/vm/vm.go @@ -303,6 +303,13 @@ func (v *VM) LoadScriptWithFlags(b []byte, f callflag.CallFlag) { v.loadScriptWithCallingHash(b, nil, v.GetCurrentScriptHash(), util.Uint160{}, f, -1, 0, nil) } +// LoadDynamicScript loads the given script with the given flags. This script is +// considered to be dynamic, it can either return no value at all or return +// exactly one value. +func (v *VM) LoadDynamicScript(b []byte, f callflag.CallFlag) { + v.loadScriptWithCallingHash(b, nil, v.GetCurrentScriptHash(), util.Uint160{}, f, -1, 0, DynamicOnUnload) +} + // LoadScriptWithHash is similar to the LoadScriptWithFlags method, but it also loads // the given script hash directly into the Context to avoid its recalculations and to make // it possible to override it for deployed contracts with special hashes (the function @@ -1637,7 +1644,7 @@ func (v *VM) unloadContext(ctx *Context) { ctx.sc.static.ClearRefs(&v.refs) } if ctx.sc.onUnload != nil { - err := ctx.sc.onUnload(ctx, v.uncaughtException == nil) + err := ctx.sc.onUnload(v, ctx, v.uncaughtException == nil) if err != nil { errMessage := fmt.Sprintf("context unload callback failed: %s", err) if v.uncaughtException != nil {