neoneo-go/pkg/vm/vm.go

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package vm
import (
"crypto/sha1"
"encoding/binary"
"fmt"
"io/ioutil"
"math/big"
"os"
"reflect"
"text/tabwriter"
"unicode/utf8"
"github.com/CityOfZion/neo-go/pkg/crypto/hash"
"github.com/CityOfZion/neo-go/pkg/crypto/keys"
"github.com/CityOfZion/neo-go/pkg/util"
"github.com/CityOfZion/neo-go/pkg/vm/opcode"
"github.com/pkg/errors"
)
type errorAtInstruct struct {
ip int
op opcode.Opcode
err interface{}
}
func (e *errorAtInstruct) Error() string {
return fmt.Sprintf("error encountered at instruction %d (%s): %s", e.ip, e.op, e.err)
}
func newError(ip int, op opcode.Opcode, err interface{}) *errorAtInstruct {
return &errorAtInstruct{ip: ip, op: op, err: err}
}
// StateMessage is a vm state message which could be used as additional info for example by cli.
type StateMessage string
const (
// MaxArraySize is the maximum array size allowed in the VM.
MaxArraySize = 1024
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// MaxItemSize is the maximum item size allowed in the VM.
MaxItemSize = 1024 * 1024
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// MaxInvocationStackSize is the maximum size of an invocation stack.
MaxInvocationStackSize = 1024
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// MaxBigIntegerSizeBits is the maximum size of BigInt item in bits.
MaxBigIntegerSizeBits = 32 * 8
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// MaxStackSize is the maximum number of items allowed to be
// on all stacks at once.
MaxStackSize = 2 * 1024
maxSHLArg = MaxBigIntegerSizeBits
minSHLArg = -MaxBigIntegerSizeBits
)
// VM represents the virtual machine.
type VM struct {
state State
// callbacks to get interops.
getInterop []InteropGetterFunc
// callback to get interop price
getPrice func(*VM, opcode.Opcode, []byte) util.Fixed8
// callback to get scripts.
getScript func(util.Uint160) []byte
istack *Stack // invocation stack.
estack *Stack // execution stack.
astack *Stack // alt stack.
// Hash to verify in CHECKSIG/CHECKMULTISIG.
checkhash []byte
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itemCount map[StackItem]int
size int
gasConsumed util.Fixed8
gasLimit util.Fixed8
// Public keys cache.
keys map[string]*keys.PublicKey
}
// New returns a new VM object ready to load .avm bytecode scripts.
func New() *VM {
vm := &VM{
getInterop: make([]InteropGetterFunc, 0, 3), // 3 functions is typical for our default usage.
getScript: nil,
state: haltState,
istack: NewStack("invocation"),
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itemCount: make(map[StackItem]int),
keys: make(map[string]*keys.PublicKey),
}
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vm.estack = vm.newItemStack("evaluation")
vm.astack = vm.newItemStack("alt")
vm.RegisterInteropGetter(getDefaultVMInterop)
return vm
}
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func (v *VM) newItemStack(n string) *Stack {
s := NewStack(n)
s.size = &v.size
s.itemCount = v.itemCount
return s
}
// RegisterInteropGetter registers the given InteropGetterFunc into VM. There
// can be many interop getters and they're probed in LIFO order wrt their
// registration time.
func (v *VM) RegisterInteropGetter(f InteropGetterFunc) {
v.getInterop = append(v.getInterop, f)
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}
// SetPriceGetter registers the given PriceGetterFunc in v.
// f accepts vm's Context, current instruction and instruction parameter.
func (v *VM) SetPriceGetter(f func(*VM, opcode.Opcode, []byte) util.Fixed8) {
v.getPrice = f
}
// GasConsumed returns the amount of GAS consumed during execution.
func (v *VM) GasConsumed() util.Fixed8 {
return v.gasConsumed
}
// SetGasLimit sets maximum amount of gas which v can spent.
// If max <= 0, no limit is imposed.
func (v *VM) SetGasLimit(max util.Fixed8) {
v.gasLimit = max
}
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// Estack returns the evaluation stack so interop hooks can utilize this.
func (v *VM) Estack() *Stack {
return v.estack
}
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// Astack returns the alt stack so interop hooks can utilize this.
func (v *VM) Astack() *Stack {
return v.astack
}
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// Istack returns the invocation stack so interop hooks can utilize this.
func (v *VM) Istack() *Stack {
return v.istack
}
// SetPublicKeys sets internal key cache to the specified value (note
// that it doesn't copy them).
func (v *VM) SetPublicKeys(keys map[string]*keys.PublicKey) {
v.keys = keys
}
// GetPublicKeys returns internal key cache (note that it doesn't copy it).
func (v *VM) GetPublicKeys() map[string]*keys.PublicKey {
return v.keys
}
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// LoadArgs loads in the arguments used in the Mian entry point.
func (v *VM) LoadArgs(method []byte, args []StackItem) {
if len(args) > 0 {
v.estack.PushVal(args)
}
if method != nil {
v.estack.PushVal(method)
}
}
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// PrintOps prints the opcodes of the current loaded program to stdout.
func (v *VM) PrintOps() {
w := tabwriter.NewWriter(os.Stdout, 0, 0, 4, ' ', 0)
fmt.Fprintln(w, "INDEX\tOPCODE\tPARAMETER\t")
realctx := v.Context()
ctx := realctx.Copy()
ctx.ip = 0
ctx.nextip = 0
for {
cursor := ""
instr, parameter, err := ctx.Next()
if ctx.ip == realctx.ip {
cursor = "<<"
}
if err != nil {
fmt.Fprintf(w, "%d\t%s\tERROR: %s\t%s\n", ctx.ip, instr, err, cursor)
break
}
var desc = ""
if parameter != nil {
switch instr {
case opcode.JMP, opcode.JMPIF, opcode.JMPIFNOT, opcode.CALL:
offset := int16(binary.LittleEndian.Uint16(parameter))
desc = fmt.Sprintf("%d (%d/%x)", ctx.ip+int(offset), offset, parameter)
case opcode.SYSCALL:
desc = fmt.Sprintf("%q", parameter)
case opcode.APPCALL, opcode.TAILCALL:
desc = fmt.Sprintf("%x", parameter)
default:
if utf8.Valid(parameter) {
desc = fmt.Sprintf("%x (%q)", parameter, parameter)
} else {
desc = fmt.Sprintf("%x", parameter)
}
}
}
fmt.Fprintf(w, "%d\t%s\t%s\t%s\n", ctx.ip, instr, desc, cursor)
if ctx.nextip >= len(ctx.prog) {
break
}
}
w.Flush()
}
// AddBreakPoint adds a breakpoint to the current context.
func (v *VM) AddBreakPoint(n int) {
ctx := v.Context()
ctx.breakPoints = append(ctx.breakPoints, n)
}
// AddBreakPointRel adds a breakpoint relative to the current
// instruction pointer.
func (v *VM) AddBreakPointRel(n int) {
ctx := v.Context()
v.AddBreakPoint(ctx.ip + n)
}
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// LoadFile loads a program from the given path, ready to execute it.
func (v *VM) LoadFile(path string) error {
b, err := ioutil.ReadFile(path)
if err != nil {
return err
}
v.Load(b)
return nil
}
// Load initializes the VM with the program given.
func (v *VM) Load(prog []byte) {
// Clear all stacks and state, it could be a reload.
v.istack.Clear()
v.estack.Clear()
v.astack.Clear()
v.state = noneState
v.gasConsumed = 0
v.LoadScript(prog)
}
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// LoadScript loads a script from the internal script table. It
// will immediately push a new context created from this script to
// the invocation stack and starts executing it.
func (v *VM) LoadScript(b []byte) {
ctx := NewContext(b)
ctx.estack = v.estack
ctx.astack = v.astack
v.istack.PushVal(ctx)
}
// loadScriptWithHash if similar to the LoadScript method, but it also loads
// given script hash directly into the Context to avoid its recalculations. It's
// up to user of this function to make sure the script and hash match each other.
func (v *VM) loadScriptWithHash(b []byte, hash util.Uint160) {
v.LoadScript(b)
v.istack.Top().Value().(*Context).scriptHash = hash
}
// Context returns the current executed context. Nil if there is no context,
// which implies no program is loaded.
func (v *VM) Context() *Context {
if v.istack.Len() == 0 {
return nil
}
return v.istack.Peek(0).Value().(*Context)
}
// PopResult is used to pop the first item of the evaluation stack. This allows
// us to test compiler and vm in a bi-directional way.
func (v *VM) PopResult() interface{} {
e := v.estack.Pop()
if e != nil {
return e.Value()
}
return nil
}
// Stack returns json formatted representation of the given stack.
func (v *VM) Stack(n string) string {
var s *Stack
if n == "astack" {
s = v.astack
}
if n == "istack" {
s = v.istack
}
if n == "estack" {
s = v.estack
}
return buildStackOutput(s)
}
// State returns string representation of the state for the VM.
func (v *VM) State() string {
return v.state.String()
}
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// Ready returns true if the VM ready to execute the loaded program.
// Will return false if no program is loaded.
func (v *VM) Ready() bool {
return v.istack.Len() > 0
}
// Run starts the execution of the loaded program.
func (v *VM) Run() error {
if !v.Ready() {
v.state = faultState
return errors.New("no program loaded")
}
if v.state.HasFlag(faultState) {
// VM already ran something and failed, in general its state is
// undefined in this case so we can't run anything.
return errors.New("VM has failed")
}
// haltState (the default) or breakState are safe to continue.
v.state = noneState
for {
// check for breakpoint before executing the next instruction
ctx := v.Context()
if ctx != nil && ctx.atBreakPoint() {
v.state |= breakState
}
switch {
case v.state.HasFlag(faultState):
// Should be caught and reported already by the v.Step(),
// but we're checking here anyway just in case.
return errors.New("VM has failed")
case v.state.HasFlag(haltState), v.state.HasFlag(breakState):
// Normal exit from this loop.
return nil
case v.state == noneState:
if err := v.Step(); err != nil {
return err
}
default:
v.state = faultState
return errors.New("unknown state")
}
}
}
// Step 1 instruction in the program.
func (v *VM) Step() error {
ctx := v.Context()
op, param, err := ctx.Next()
if err != nil {
v.state = faultState
return newError(ctx.ip, op, err)
}
return v.execute(ctx, op, param)
}
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// StepInto behaves the same as “step over” in case if the line does not contain a function. Otherwise
// the debugger will enter the called function and continue line-by-line debugging there.
func (v *VM) StepInto() error {
ctx := v.Context()
if ctx == nil {
v.state |= haltState
}
if v.HasStopped() {
return nil
}
if ctx != nil && ctx.prog != nil {
op, param, err := ctx.Next()
if err != nil {
v.state = faultState
return newError(ctx.ip, op, err)
}
vErr := v.execute(ctx, op, param)
if vErr != nil {
return vErr
}
}
cctx := v.Context()
if cctx != nil && cctx.atBreakPoint() {
v.state = breakState
}
return nil
}
// StepOut takes the debugger to the line where the current function was called.
func (v *VM) StepOut() error {
var err error
if v.state == breakState {
v.state = noneState
} else {
v.state = breakState
}
expSize := v.istack.len
for v.state == noneState && v.istack.len >= expSize {
err = v.StepInto()
}
return err
}
// StepOver takes the debugger to the line that will step over a given line.
// If the line contains a function the function will be executed and the result returned without debugging each line.
func (v *VM) StepOver() error {
var err error
if v.HasStopped() {
return err
}
if v.state == breakState {
v.state = noneState
} else {
v.state = breakState
}
expSize := v.istack.len
for {
err = v.StepInto()
if !(v.state == noneState && v.istack.len > expSize) {
break
}
}
if v.state == noneState {
v.state = breakState
}
return err
}
// HasFailed returns whether VM is in the failed state now. Usually used to
// check status after Run.
func (v *VM) HasFailed() bool {
return v.state.HasFlag(faultState)
}
// HasStopped returns whether VM is in Halt or Failed state.
func (v *VM) HasStopped() bool {
return v.state.HasFlag(haltState) || v.state.HasFlag(faultState)
}
// HasHalted returns whether VM is in Halt state.
func (v *VM) HasHalted() bool {
return v.state.HasFlag(haltState)
}
// AtBreakpoint returns whether VM is at breakpoint.
func (v *VM) AtBreakpoint() bool {
return v.state.HasFlag(breakState)
}
// SetCheckedHash sets checked hash for CHECKSIG and CHECKMULTISIG instructions.
func (v *VM) SetCheckedHash(h []byte) {
v.checkhash = make([]byte, len(h))
copy(v.checkhash, h)
}
// SetScriptGetter sets the script getter for CALL instructions.
func (v *VM) SetScriptGetter(gs func(util.Uint160) []byte) {
v.getScript = gs
}
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// GetInteropID converts instruction parameter to an interop ID.
func GetInteropID(parameter []byte) uint32 {
if len(parameter) == 4 {
return binary.LittleEndian.Uint32(parameter)
}
return InteropNameToID(parameter)
}
// GetInteropByID returns interop function together with price.
// Registered callbacks are checked in LIFO order.
func (v *VM) GetInteropByID(id uint32) *InteropFuncPrice {
for i := len(v.getInterop) - 1; i >= 0; i-- {
if ifunc := v.getInterop[i](id); ifunc != nil {
return ifunc
}
}
return nil
}
// execute performs an instruction cycle in the VM. Acting on the instruction (opcode).
func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err error) {
// Instead of polluting the whole VM logic with error handling, we will recover
// each panic at a central point, putting the VM in a fault state and setting error.
defer func() {
if errRecover := recover(); errRecover != nil {
v.state = faultState
err = newError(ctx.ip, op, errRecover)
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} else if v.size > MaxStackSize {
v.state = faultState
err = newError(ctx.ip, op, "stack is too big")
}
}()
if v.getPrice != nil && ctx.ip < len(ctx.prog) {
v.gasConsumed += v.getPrice(v, op, parameter)
if v.gasLimit > 0 && v.gasConsumed > v.gasLimit {
panic("gas limit is exceeded")
}
}
if op >= opcode.PUSHBYTES1 && op <= opcode.PUSHBYTES75 {
v.estack.PushVal(parameter)
return
}
switch op {
case opcode.PUSHM1, opcode.PUSH1, opcode.PUSH2, opcode.PUSH3,
opcode.PUSH4, opcode.PUSH5, opcode.PUSH6, opcode.PUSH7,
opcode.PUSH8, opcode.PUSH9, opcode.PUSH10, opcode.PUSH11,
opcode.PUSH12, opcode.PUSH13, opcode.PUSH14, opcode.PUSH15,
opcode.PUSH16:
val := int(op) - int(opcode.PUSH1) + 1
v.estack.PushVal(val)
case opcode.PUSH0:
v.estack.PushVal([]byte{})
case opcode.PUSHDATA1, opcode.PUSHDATA2, opcode.PUSHDATA4:
v.estack.PushVal(parameter)
// Stack operations.
case opcode.TOALTSTACK:
v.astack.Push(v.estack.Pop())
case opcode.FROMALTSTACK:
v.estack.Push(v.astack.Pop())
case opcode.DUPFROMALTSTACK:
v.estack.Push(v.astack.Dup(0))
case opcode.DUP:
v.estack.Push(v.estack.Dup(0))
case opcode.SWAP:
err := v.estack.Swap(1, 0)
if err != nil {
panic(err.Error())
}
case opcode.TUCK:
a := v.estack.Dup(0)
if a == nil {
panic("no top-level element found")
}
if v.estack.Len() < 2 {
panic("can't TUCK with a one-element stack")
}
v.estack.InsertAt(a, 2)
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case opcode.CAT:
b := v.estack.Pop().Bytes()
a := v.estack.Pop().Bytes()
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if l := len(a) + len(b); l > MaxItemSize {
panic(fmt.Sprintf("too big item: %d", l))
}
ab := append(a, b...)
v.estack.PushVal(ab)
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case opcode.SUBSTR:
l := int(v.estack.Pop().BigInt().Int64())
if l < 0 {
panic("negative length")
}
o := int(v.estack.Pop().BigInt().Int64())
if o < 0 {
panic("negative index")
}
s := v.estack.Pop().Bytes()
if o > len(s) {
// panic("invalid offset")
// FIXME revert when NEO 3.0 https://github.com/nspcc-dev/neo-go/issues/477
v.estack.PushVal("")
break
}
last := l + o
if last > len(s) {
last = len(s)
}
v.estack.PushVal(s[o:last])
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case opcode.LEFT:
l := int(v.estack.Pop().BigInt().Int64())
if l < 0 {
panic("negative length")
}
s := v.estack.Pop().Bytes()
if t := len(s); l > t {
l = t
}
v.estack.PushVal(s[:l])
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case opcode.RIGHT:
l := int(v.estack.Pop().BigInt().Int64())
if l < 0 {
panic("negative length")
}
s := v.estack.Pop().Bytes()
v.estack.PushVal(s[len(s)-l:])
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case opcode.XDROP:
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n := int(v.estack.Pop().BigInt().Int64())
if n < 0 {
panic("invalid length")
}
e := v.estack.RemoveAt(n)
if e == nil {
panic("bad index")
}
case opcode.XSWAP:
n := int(v.estack.Pop().BigInt().Int64())
err := v.estack.Swap(n, 0)
if err != nil {
panic(err.Error())
}
case opcode.XTUCK:
n := int(v.estack.Pop().BigInt().Int64())
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if n <= 0 {
panic("XTUCK: invalid length")
}
a := v.estack.Dup(0)
if a == nil {
panic("no top-level element found")
}
if n > v.estack.Len() {
panic("can't push to the position specified")
}
v.estack.InsertAt(a, n)
case opcode.ROT:
err := v.estack.Roll(2)
if err != nil {
panic(err.Error())
}
case opcode.DEPTH:
v.estack.PushVal(v.estack.Len())
case opcode.NIP:
elem := v.estack.RemoveAt(1)
if elem == nil {
panic("no second element found")
}
case opcode.OVER:
a := v.estack.Dup(1)
if a == nil {
panic("no second element found")
}
v.estack.Push(a)
case opcode.PICK:
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n := int(v.estack.Pop().BigInt().Int64())
if n < 0 {
panic("negative stack item returned")
}
a := v.estack.Dup(n)
if a == nil {
panic("no nth element found")
}
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v.estack.Push(a)
case opcode.ROLL:
n := int(v.estack.Pop().BigInt().Int64())
err := v.estack.Roll(n)
if err != nil {
panic(err.Error())
}
case opcode.DROP:
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if v.estack.Len() < 1 {
panic("stack is too small")
}
v.estack.Pop()
case opcode.EQUAL:
b := v.estack.Pop()
if b == nil {
panic("no top-level element found")
}
a := v.estack.Pop()
if a == nil {
panic("no second-to-the-top element found")
}
if ta, ok := a.value.(*ArrayItem); ok {
if tb, ok := b.value.(*ArrayItem); ok {
v.estack.PushVal(ta == tb)
break
}
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} else if ma, ok := a.value.(*MapItem); ok {
if mb, ok := b.value.(*MapItem); ok {
v.estack.PushVal(ma == mb)
break
}
}
v.estack.PushVal(reflect.DeepEqual(a, b))
// Bit operations.
case opcode.INVERT:
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// inplace
e := v.estack.Peek(0)
i := e.BigInt()
e.value = makeStackItem(i.Not(i))
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case opcode.AND:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(new(big.Int).And(b, a))
case opcode.OR:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(new(big.Int).Or(b, a))
case opcode.XOR:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(new(big.Int).Xor(b, a))
// Numeric operations.
case opcode.ADD:
a := v.estack.Pop().BigInt()
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v.checkBigIntSize(a)
b := v.estack.Pop().BigInt()
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v.checkBigIntSize(b)
c := new(big.Int).Add(a, b)
v.checkBigIntSize(c)
v.estack.PushVal(c)
case opcode.SUB:
b := v.estack.Pop().BigInt()
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v.checkBigIntSize(b)
a := v.estack.Pop().BigInt()
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v.checkBigIntSize(a)
c := new(big.Int).Sub(a, b)
v.checkBigIntSize(c)
v.estack.PushVal(c)
case opcode.DIV:
b := v.estack.Pop().BigInt()
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v.checkBigIntSize(b)
a := v.estack.Pop().BigInt()
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v.checkBigIntSize(a)
v.estack.PushVal(new(big.Int).Div(a, b))
case opcode.MUL:
a := v.estack.Pop().BigInt()
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v.checkBigIntSize(a)
b := v.estack.Pop().BigInt()
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v.checkBigIntSize(b)
c := new(big.Int).Mul(a, b)
v.checkBigIntSize(c)
v.estack.PushVal(c)
case opcode.MOD:
b := v.estack.Pop().BigInt()
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v.checkBigIntSize(b)
a := v.estack.Pop().BigInt()
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v.checkBigIntSize(a)
v.estack.PushVal(new(big.Int).Mod(a, b))
case opcode.SHL, opcode.SHR:
b := v.estack.Pop().BigInt().Int64()
if b == 0 {
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return
} else if b < minSHLArg || b > maxSHLArg {
panic(fmt.Sprintf("operand must be between %d and %d", minSHLArg, maxSHLArg))
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}
a := v.estack.Pop().BigInt()
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v.checkBigIntSize(a)
var item big.Int
if op == opcode.SHL {
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item.Lsh(a, uint(b))
} else {
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item.Rsh(a, uint(b))
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}
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v.checkBigIntSize(&item)
v.estack.PushVal(&item)
case opcode.BOOLAND:
b := v.estack.Pop().Bool()
a := v.estack.Pop().Bool()
v.estack.PushVal(a && b)
case opcode.BOOLOR:
b := v.estack.Pop().Bool()
a := v.estack.Pop().Bool()
v.estack.PushVal(a || b)
case opcode.NUMEQUAL:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(a.Cmp(b) == 0)
case opcode.NUMNOTEQUAL:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(a.Cmp(b) != 0)
case opcode.LT:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(a.Cmp(b) == -1)
case opcode.GT:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(a.Cmp(b) == 1)
case opcode.LTE:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(a.Cmp(b) <= 0)
case opcode.GTE:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
v.estack.PushVal(a.Cmp(b) >= 0)
case opcode.MIN:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
val := a
if a.Cmp(b) == 1 {
val = b
}
v.estack.PushVal(val)
case opcode.MAX:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
val := a
if a.Cmp(b) == -1 {
val = b
}
v.estack.PushVal(val)
case opcode.WITHIN:
b := v.estack.Pop().BigInt()
a := v.estack.Pop().BigInt()
x := v.estack.Pop().BigInt()
v.estack.PushVal(a.Cmp(x) <= 0 && x.Cmp(b) == -1)
case opcode.INC:
x := v.estack.Pop().BigInt()
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a := new(big.Int).Add(x, big.NewInt(1))
v.checkBigIntSize(a)
v.estack.PushVal(a)
case opcode.DEC:
x := v.estack.Pop().BigInt()
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a := new(big.Int).Sub(x, big.NewInt(1))
v.checkBigIntSize(a)
v.estack.PushVal(a)
case opcode.SIGN:
x := v.estack.Pop().BigInt()
v.estack.PushVal(x.Sign())
case opcode.NEGATE:
x := v.estack.Pop().BigInt()
v.estack.PushVal(x.Neg(x))
case opcode.ABS:
x := v.estack.Pop().BigInt()
v.estack.PushVal(x.Abs(x))
case opcode.NOT:
x := v.estack.Pop().Bool()
v.estack.PushVal(!x)
case opcode.NZ:
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x := v.estack.Pop().BigInt()
v.estack.PushVal(x.Cmp(big.NewInt(0)) != 0)
// Object operations.
case opcode.NEWARRAY:
item := v.estack.Pop()
switch t := item.value.(type) {
case *StructItem:
arr := make([]StackItem, len(t.value))
copy(arr, t.value)
v.estack.PushVal(&ArrayItem{arr})
case *ArrayItem:
v.estack.PushVal(t)
default:
n := item.BigInt().Int64()
if n > MaxArraySize {
panic("too long array")
}
items := makeArrayOfFalses(int(n))
v.estack.PushVal(&ArrayItem{items})
}
case opcode.NEWSTRUCT:
item := v.estack.Pop()
switch t := item.value.(type) {
case *ArrayItem:
arr := make([]StackItem, len(t.value))
copy(arr, t.value)
v.estack.PushVal(&StructItem{arr})
case *StructItem:
v.estack.PushVal(t)
default:
n := item.BigInt().Int64()
if n > MaxArraySize {
panic("too long struct")
}
items := makeArrayOfFalses(int(n))
v.estack.PushVal(&StructItem{items})
}
case opcode.APPEND:
itemElem := v.estack.Pop()
arrElem := v.estack.Pop()
val := cloneIfStruct(itemElem.value)
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switch t := arrElem.value.(type) {
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case *ArrayItem:
arr := t.Value().([]StackItem)
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if len(arr) >= MaxArraySize {
panic("too long array")
}
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arr = append(arr, val)
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t.value = arr
case *StructItem:
arr := t.Value().([]StackItem)
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if len(arr) >= MaxArraySize {
panic("too long struct")
}
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arr = append(arr, val)
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t.value = arr
default:
panic("APPEND: not of underlying type Array")
}
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v.estack.updateSizeAdd(val)
case opcode.PACK:
n := int(v.estack.Pop().BigInt().Int64())
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if n < 0 || n > v.estack.Len() || n > MaxArraySize {
panic("OPACK: invalid length")
}
items := make([]StackItem, n)
for i := 0; i < n; i++ {
items[i] = v.estack.Pop().value
}
v.estack.PushVal(items)
case opcode.UNPACK:
a := v.estack.Pop().Array()
l := len(a)
for i := l - 1; i >= 0; i-- {
v.estack.PushVal(a[i])
}
v.estack.PushVal(l)
case opcode.PICKITEM:
key := v.estack.Pop()
validateMapKey(key)
obj := v.estack.Pop()
index := int(key.BigInt().Int64())
switch t := obj.value.(type) {
// Struct and Array items have their underlying value as []StackItem.
case *ArrayItem, *StructItem:
arr := t.Value().([]StackItem)
if index < 0 || index >= len(arr) {
panic("PICKITEM: invalid index")
}
item := arr[index].Dup()
v.estack.PushVal(item)
case *MapItem:
if !t.Has(key.value) {
panic("invalid key")
}
k := toMapKey(key.value)
v.estack.Push(&Element{value: t.value[k].Dup()})
default:
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arr := obj.Bytes()
if index < 0 || index >= len(arr) {
panic("PICKITEM: invalid index")
}
item := arr[index]
v.estack.PushVal(int(item))
}
case opcode.SETITEM:
item := v.estack.Pop().value
key := v.estack.Pop()
validateMapKey(key)
obj := v.estack.Pop()
switch t := obj.value.(type) {
// Struct and Array items have their underlying value as []StackItem.
case *ArrayItem, *StructItem:
arr := t.Value().([]StackItem)
index := int(key.BigInt().Int64())
if index < 0 || index >= len(arr) {
panic("SETITEM: invalid index")
}
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v.estack.updateSizeRemove(arr[index])
arr[index] = item
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v.estack.updateSizeAdd(arr[index])
case *MapItem:
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if t.Has(key.value) {
v.estack.updateSizeRemove(item)
} else if len(t.value) >= MaxArraySize {
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panic("too big map")
}
t.Add(key.value, item)
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v.estack.updateSizeAdd(item)
default:
panic(fmt.Sprintf("SETITEM: invalid item type %s", t))
}
case opcode.REVERSE:
a := v.estack.Pop().Array()
if len(a) > 1 {
for i, j := 0, len(a)-1; i <= j; i, j = i+1, j-1 {
a[i], a[j] = a[j], a[i]
}
}
case opcode.REMOVE:
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key := v.estack.Pop()
validateMapKey(key)
elem := v.estack.Pop()
switch t := elem.value.(type) {
case *ArrayItem:
a := t.value
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k := int(key.BigInt().Int64())
if k < 0 || k >= len(a) {
panic("REMOVE: invalid index")
}
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v.estack.updateSizeRemove(a[k])
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a = append(a[:k], a[k+1:]...)
t.value = a
case *StructItem:
a := t.value
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k := int(key.BigInt().Int64())
if k < 0 || k >= len(a) {
panic("REMOVE: invalid index")
}
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v.estack.updateSizeRemove(a[k])
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a = append(a[:k], a[k+1:]...)
t.value = a
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case *MapItem:
m := t.value
k := toMapKey(key.value)
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v.estack.updateSizeRemove(m[k])
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delete(m, k)
default:
panic("REMOVE: invalid type")
}
case opcode.ARRAYSIZE:
elem := v.estack.Pop()
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// Cause there is no native (byte) item type here, hence we need to check
// the type of the item for array size operations.
switch t := elem.Value().(type) {
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case []StackItem:
v.estack.PushVal(len(t))
case map[interface{}]StackItem:
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v.estack.PushVal(len(t))
default:
v.estack.PushVal(len(elem.Bytes()))
}
case opcode.SIZE:
elem := v.estack.Pop()
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arr := elem.Bytes()
v.estack.PushVal(len(arr))
case opcode.JMP, opcode.JMPIF, opcode.JMPIFNOT:
offset := v.getJumpOffset(ctx, parameter)
cond := true
if op != opcode.JMP {
cond = v.estack.Pop().Bool() == (op == opcode.JMPIF)
}
v.jumpIf(ctx, offset, cond)
case opcode.CALL:
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v.checkInvocationStackSize()
newCtx := ctx.Copy()
newCtx.rvcount = -1
v.istack.PushVal(newCtx)
offset := v.getJumpOffset(newCtx, parameter)
v.jumpIf(newCtx, offset, true)
case opcode.SYSCALL:
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interopID := GetInteropID(parameter)
ifunc := v.GetInteropByID(interopID)
if ifunc == nil {
panic(fmt.Sprintf("interop hook (%q/0x%x) not registered", parameter, interopID))
}
if err := ifunc.Func(v); err != nil {
panic(fmt.Sprintf("failed to invoke syscall: %s", err))
}
case opcode.APPCALL, opcode.TAILCALL:
if v.getScript == nil {
panic("no getScript callback is set up")
}
if op == opcode.APPCALL {
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v.checkInvocationStackSize()
}
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hash, err := util.Uint160DecodeBytesBE(parameter)
if err != nil {
panic(err)
}
script := v.getScript(hash)
if script == nil {
panic("could not find script")
}
if op == opcode.TAILCALL {
_ = v.istack.Pop()
}
v.loadScriptWithHash(script, hash)
case opcode.RET:
oldCtx := v.istack.Pop().Value().(*Context)
rvcount := oldCtx.rvcount
oldEstack := v.estack
if rvcount > 0 && oldEstack.Len() < rvcount {
panic("missing some return elements")
}
if v.istack.Len() == 0 {
v.state = haltState
break
}
newEstack := v.Context().estack
if oldEstack != newEstack {
if rvcount < 0 {
rvcount = oldEstack.Len()
}
for i := rvcount; i > 0; i-- {
elem := oldEstack.RemoveAt(i - 1)
newEstack.Push(elem)
}
v.estack = newEstack
v.astack = v.Context().astack
}
case opcode.CHECKSIG, opcode.VERIFY:
var hashToCheck []byte
keyb := v.estack.Pop().Bytes()
signature := v.estack.Pop().Bytes()
if op == opcode.CHECKSIG {
if v.checkhash == nil {
panic("VM is not set up properly for signature checks")
}
hashToCheck = v.checkhash
} else { // VERIFY
msg := v.estack.Pop().Bytes()
2019-11-27 09:23:18 +00:00
hashToCheck = hash.Sha256(msg).BytesBE()
}
pkey := v.bytesToPublicKey(keyb)
res := pkey.Verify(signature, hashToCheck)
v.estack.PushVal(res)
case opcode.CHECKMULTISIG:
pkeys, err := v.estack.popSigElements()
if err != nil {
panic(fmt.Sprintf("wrong parameters: %s", err.Error()))
}
sigs, err := v.estack.popSigElements()
if err != nil {
panic(fmt.Sprintf("wrong parameters: %s", err.Error()))
}
// It's ok to have more keys than there are signatures (it would
// just mean that some keys didn't sign), but not the other way around.
if len(pkeys) < len(sigs) {
panic("more signatures than there are keys")
}
if v.checkhash == nil {
panic("VM is not set up properly for signature checks")
}
sigok := true
// j counts keys and i counts signatures.
j := 0
for i := 0; sigok && j < len(pkeys) && i < len(sigs); {
pkey := v.bytesToPublicKey(pkeys[j])
// We only move to the next signature if the check was
// successful, but if it's not maybe the next key will
// fit, so we always move to the next key.
if pkey.Verify(sigs[i], v.checkhash) {
i++
}
j++
// When there are more signatures left to check than
// there are keys the check won't successed for sure.
if len(sigs)-i > len(pkeys)-j {
sigok = false
}
}
v.estack.PushVal(sigok)
case opcode.NEWMAP:
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v.estack.Push(&Element{value: NewMapItem()})
case opcode.KEYS:
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item := v.estack.Pop()
if item == nil {
panic("no argument")
}
m, ok := item.value.(*MapItem)
if !ok {
panic("not a Map")
}
arr := make([]StackItem, 0, len(m.value))
for k := range m.value {
arr = append(arr, makeStackItem(k))
}
v.estack.PushVal(arr)
case opcode.VALUES:
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item := v.estack.Pop()
if item == nil {
panic("no argument")
}
var arr []StackItem
switch t := item.value.(type) {
case *ArrayItem, *StructItem:
src := t.Value().([]StackItem)
arr = make([]StackItem, len(src))
for i := range src {
arr[i] = cloneIfStruct(src[i])
}
case *MapItem:
arr = make([]StackItem, 0, len(t.value))
for k := range t.value {
arr = append(arr, cloneIfStruct(t.value[k]))
}
default:
panic("not a Map, Array or Struct")
}
v.estack.PushVal(arr)
case opcode.HASKEY:
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key := v.estack.Pop()
validateMapKey(key)
c := v.estack.Pop()
if c == nil {
panic("no value found")
}
switch t := c.value.(type) {
case *ArrayItem, *StructItem:
index := key.BigInt().Int64()
if index < 0 {
panic("negative index")
}
v.estack.PushVal(index < int64(len(c.Array())))
case *MapItem:
v.estack.PushVal(t.Has(key.value))
default:
panic("wrong collection type")
}
// Cryptographic operations.
case opcode.SHA1:
b := v.estack.Pop().Bytes()
sha := sha1.New()
sha.Write(b)
v.estack.PushVal(sha.Sum(nil))
case opcode.SHA256:
b := v.estack.Pop().Bytes()
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v.estack.PushVal(hash.Sha256(b).BytesBE())
case opcode.HASH160:
b := v.estack.Pop().Bytes()
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v.estack.PushVal(hash.Hash160(b).BytesBE())
case opcode.HASH256:
b := v.estack.Pop().Bytes()
2019-11-27 09:23:18 +00:00
v.estack.PushVal(hash.DoubleSha256(b).BytesBE())
case opcode.NOP:
// unlucky ^^
case opcode.CALLI, opcode.CALLE, opcode.CALLED, opcode.CALLET, opcode.CALLEDT:
var (
tailCall = (op == opcode.CALLET || op == opcode.CALLEDT)
hashOnStack = (op == opcode.CALLED || op == opcode.CALLEDT)
addElement int
newCtx *Context
)
if hashOnStack {
addElement = 1
}
rvcount := int(parameter[0])
pcount := int(parameter[1])
if v.estack.Len() < pcount+addElement {
panic("missing some parameters")
}
2019-10-29 08:01:06 +00:00
if tailCall {
if ctx.rvcount != rvcount {
panic("context and parameter rvcount mismatch")
}
} else {
v.checkInvocationStackSize()
}
if op == opcode.CALLI {
newCtx = ctx.Copy()
} else {
var hashBytes []byte
if hashOnStack {
hashBytes = v.estack.Pop().Bytes()
} else {
hashBytes = parameter[2:]
}
2019-11-27 09:20:31 +00:00
hash, err := util.Uint160DecodeBytesBE(hashBytes)
if err != nil {
panic(err)
}
script := v.getScript(hash)
if script == nil {
panic(fmt.Sprintf("could not find script %s", hash))
}
newCtx = NewContext(script)
newCtx.scriptHash = hash
}
newCtx.rvcount = rvcount
newCtx.estack = NewStack("evaluation")
newCtx.astack = NewStack("alt")
// Going backwards to naturally push things onto the new stack.
for i := pcount; i > 0; i-- {
elem := v.estack.RemoveAt(i - 1)
newCtx.estack.Push(elem)
}
if tailCall {
_ = v.istack.Pop()
}
v.istack.PushVal(newCtx)
v.estack = newCtx.estack
v.astack = newCtx.astack
if op == opcode.CALLI {
offset := v.getJumpOffset(newCtx, parameter[2:])
v.jumpIf(newCtx, offset, true)
}
case opcode.THROW:
panic("THROW")
case opcode.THROWIFNOT:
if !v.estack.Pop().Bool() {
panic("THROWIFNOT")
}
default:
panic(fmt.Sprintf("unknown opcode %s", op.String()))
}
return
}
// jumpIf performs jump to offset if cond is true.
func (v *VM) jumpIf(ctx *Context, offset int, cond bool) {
if cond {
ctx.nextip = offset
}
}
// getJumpOffset returns instruction number in a current context
// to a which JMP should be performed.
// parameter is interpreted as little-endian int16.
func (v *VM) getJumpOffset(ctx *Context, parameter []byte) int {
rOffset := int16(binary.LittleEndian.Uint16(parameter))
offset := ctx.ip + int(rOffset)
if offset < 0 || offset > len(ctx.prog) {
panic(fmt.Sprintf("JMP: invalid offset %d ip at %d", offset, ctx.ip))
}
return offset
}
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func cloneIfStruct(item StackItem) StackItem {
switch it := item.(type) {
case *StructItem:
return it.Clone()
default:
return it
}
}
func makeArrayOfFalses(n int) []StackItem {
items := make([]StackItem, n)
for i := range items {
items[i] = &BoolItem{false}
}
return items
}
2019-09-24 12:25:57 +00:00
func validateMapKey(key *Element) {
if key == nil {
panic("no key found")
}
switch key.value.(type) {
case *ArrayItem, *StructItem, *MapItem:
panic("key can't be a collection")
}
}
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func (v *VM) checkInvocationStackSize() {
if v.istack.len >= MaxInvocationStackSize {
panic("invocation stack is too big")
}
}
2019-11-07 09:14:36 +00:00
func (v *VM) checkBigIntSize(a *big.Int) {
if a.BitLen() > MaxBigIntegerSizeBits {
panic("big integer is too big")
}
}
// bytesToPublicKey is a helper deserializing keys using cache and panicing on
// error.
func (v *VM) bytesToPublicKey(b []byte) *keys.PublicKey {
var pkey *keys.PublicKey
s := string(b)
if v.keys[s] != nil {
pkey = v.keys[s]
} else {
pkey = &keys.PublicKey{}
err := pkey.DecodeBytes(b)
if err != nil {
panic(err.Error())
}
v.keys[s] = pkey
}
return pkey
}