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native/vm: add script check for deployed contracts

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Refs. #1699.
This commit is contained in:
Roman Khimov 2021-02-09 21:42:39 +03:00
parent a6e25cffde
commit 158f0d9d9c
8 changed files with 321 additions and 14 deletions
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22
pkg/core/native/management.go
View file

@ -22,6 +22,8 @@ import (
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/nef"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/util/bitfield"
"github.com/nspcc-dev/neo-go/pkg/vm"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
@ -273,6 +275,10 @@ func (m *Management) Deploy(d dao.DAO, sender util.Uint160, neff *nef.File, mani
if err != nil {
return nil, fmt.Errorf("invalid manifest: %w", err)
}
err = checkScriptAndMethods(neff.Script, manif.ABI.Methods)
if err != nil {
return nil, err
}
newcontract := &state.Contract{
ID: id,
Hash: h,
@ -334,6 +340,10 @@ func (m *Management) Update(d dao.DAO, hash util.Uint160, neff *nef.File, manif
m.markUpdated(hash)
contract.Manifest = *manif
}
err = checkScriptAndMethods(contract.NEF.Script, contract.Manifest.ABI.Methods)
if err != nil {
return nil, err
}
contract.UpdateCounter++
err = m.PutContractState(d, contract)
if err != nil {
@ -551,3 +561,15 @@ func (m *Management) emitNotification(ic *interop.Context, name string, hash uti
}
ic.Notifications = append(ic.Notifications, ne)
}
func checkScriptAndMethods(script []byte, methods []manifest.Method) error {
l := len(script)
offsets := bitfield.New(l)
for i := range methods {
if methods[i].Offset >= l {
return errors.New("out of bounds method offset")
}
offsets.Set(methods[i].Offset)
}
return vm.IsScriptCorrect(script, offsets)
}

3
pkg/core/native/management_test.go
View file

@ -12,6 +12,7 @@ import (
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/nef"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
"github.com/stretchr/testify/require"
)
@ -19,7 +20,7 @@ func TestDeployGetUpdateDestroyContract(t *testing.T) {
mgmt := newManagement()
d := dao.NewCached(dao.NewSimple(storage.NewMemoryStore(), netmode.UnitTestNet, false))
mgmt.Initialize(&interop.Context{DAO: d})
script := []byte{1}
script := []byte{byte(opcode.RET)}
sender := util.Uint160{1, 2, 3}
ne, err := nef.NewFile(script)
require.NoError(t, err)

50
pkg/core/native_management_test.go
View file

@ -163,6 +163,17 @@ func TestContractDeploy(t *testing.T) {
require.NoError(t, err)
checkFAULTState(t, res)
})
t.Run("bad script in NEF", func(t *testing.T) {
nf, err := nef.FileFromBytes(nef1b) // make a full copy
require.NoError(t, err)
nf.Script[0] = 0xff
nf.CalculateChecksum()
nefbad, err := nf.Bytes()
require.NoError(t, err)
res, err := invokeContractMethod(bc, 11_00000000, mgmtHash, "deploy", nefbad, manif1)
require.NoError(t, err)
checkFAULTState(t, res)
})
t.Run("int for manifest", func(t *testing.T) {
res, err := invokeContractMethod(bc, 11_00000000, mgmtHash, "deploy", nef1b, int64(1))
require.NoError(t, err)
@ -198,6 +209,32 @@ func TestContractDeploy(t *testing.T) {
require.NoError(t, err)
checkFAULTState(t, res)
})
t.Run("bad methods in manifest 1", func(t *testing.T) {
var badManifest = cs1.Manifest
badManifest.ABI.Methods = make([]manifest.Method, len(cs1.Manifest.ABI.Methods))
copy(badManifest.ABI.Methods, cs1.Manifest.ABI.Methods)
badManifest.ABI.Methods[0].Offset = 100500 // out of bounds
manifB, err := json.Marshal(badManifest)
require.NoError(t, err)
res, err := invokeContractMethod(bc, 11_00000000, mgmtHash, "deploy", nef1b, manifB)
require.NoError(t, err)
checkFAULTState(t, res)
})
t.Run("bad methods in manifest 2", func(t *testing.T) {
var badManifest = cs1.Manifest
badManifest.ABI.Methods = make([]manifest.Method, len(cs1.Manifest.ABI.Methods))
copy(badManifest.ABI.Methods, cs1.Manifest.ABI.Methods)
badManifest.ABI.Methods[0].Offset = len(cs1.NEF.Script) - 2 // Ends with `CALLT(X,X);RET`.
manifB, err := json.Marshal(badManifest)
require.NoError(t, err)
res, err := invokeContractMethod(bc, 11_00000000, mgmtHash, "deploy", nef1b, manifB)
require.NoError(t, err)
checkFAULTState(t, res)
})
t.Run("not enough GAS", func(t *testing.T) {
res, err := invokeContractMethod(bc, 1_00000000, mgmtHash, "deploy", nef1b, manif1)
require.NoError(t, err)
@ -382,6 +419,19 @@ func TestContractUpdate(t *testing.T) {
require.NoError(t, err)
checkFAULTState(t, res)
})
t.Run("manifest and script mismatch", func(t *testing.T) {
nf, err := nef.FileFromBytes(nef1b) // Make a full copy.
require.NoError(t, err)
nf.Script = append(nf.Script, byte(opcode.RET))
copy(nf.Script[1:], nf.Script) // Now all method offsets are wrong.
nf.Script[0] = byte(opcode.RET) // Even though the script is correct.
nf.CalculateChecksum()
nefnew, err := nf.Bytes()
require.NoError(t, err)
res, err := invokeContractMethod(bc, 10_00000000, cs1.Hash, "update", nefnew, manif1)
require.NoError(t, err)
checkFAULTState(t, res)
})
t.Run("change name", func(t *testing.T) {
var badManifest = cs1.Manifest

15
pkg/util/bitfield/bitfield.go
View file

@ -62,3 +62,18 @@ func (f Field) Equals(o Field) bool {
}
return true
}
// IsSubset returns true when f is a subset of o (only has bits set that are
// set in o).
func (f Field) IsSubset(o Field) bool {
if len(f) > len(o) {
return false
}
for i := range f {
r := f[i] & o[i]
if r != f[i] {
return false
}
}
return true
}

4
pkg/util/bitfield/bitfield_test.go
View file

@ -17,6 +17,7 @@ func TestFields(t *testing.T) {
b.Set(100)
require.True(t, a.IsSet(42))
require.False(t, b.IsSet(43))
require.True(t, a.IsSubset(b))
v := uint64(1<<10 | 1<<42)
require.Equal(t, v, a[0])
@ -28,14 +29,17 @@ func TestFields(t *testing.T) {
require.True(t, c.Equals(b))
z := New(128)
require.True(t, z.IsSubset(c))
c.And(a)
require.True(t, c.Equals(b))
c.And(z)
require.True(t, c.Equals(z))
c = New(64)
require.False(t, z.IsSubset(c))
c[0] = a[0]
require.False(t, c.Equals(a))
require.True(t, c.IsSubset(a))
b.And(c)
require.False(t, b.Equals(a))

62
pkg/vm/contract_checks.go
View file

@ -2,9 +2,12 @@ package vm
import (
"encoding/binary"
"errors"
"fmt"
"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
"github.com/nspcc-dev/neo-go/pkg/util/bitfield"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
@ -127,3 +130,62 @@ func IsSignatureContract(script []byte) bool {
func IsStandardContract(script []byte) bool {
return IsSignatureContract(script) || IsMultiSigContract(script)
}
// IsScriptCorrect checks script for errors and mask provided for correctness wrt
// instruction boundaries. Normally it returns nil, but can return some specific
// error if there is any.
func IsScriptCorrect(script []byte, methods bitfield.Field) error {
var (
l = len(script)
instrs = bitfield.New(l)
jumps = bitfield.New(l)
)
ctx := NewContext(script)
for ctx.nextip < l {
op, param, err := ctx.Next()
if err != nil {
return err
}
instrs.Set(ctx.ip)
switch op {
case opcode.JMP, opcode.JMPIF, opcode.JMPIFNOT, opcode.JMPEQ, opcode.JMPNE,
opcode.JMPGT, opcode.JMPGE, opcode.JMPLT, opcode.JMPLE,
opcode.CALL, opcode.ENDTRY, opcode.JMPL, opcode.JMPIFL,
opcode.JMPIFNOTL, opcode.JMPEQL, opcode.JMPNEL,
opcode.JMPGTL, opcode.JMPGEL, opcode.JMPLTL, opcode.JMPLEL,
opcode.ENDTRYL, opcode.CALLL, opcode.PUSHA:
off, _, err := calcJumpOffset(ctx, param) // It does bounds checking.
if err != nil {
return err
}
jumps.Set(off)
case opcode.TRY, opcode.TRYL:
catchP, finallyP := getTryParams(op, param)
off, _, err := calcJumpOffset(ctx, catchP)
if err != nil {
return err
}
jumps.Set(off)
off, _, err = calcJumpOffset(ctx, finallyP)
if err != nil {
return err
}
jumps.Set(off)
case opcode.NEWARRAYT, opcode.ISTYPE, opcode.CONVERT:
typ := stackitem.Type(param[0])
if !typ.IsValid() {
return fmt.Errorf("invalid type specification at offset %d", ctx.ip)
}
if typ == stackitem.AnyT && op != opcode.NEWARRAYT {
return fmt.Errorf("using type ANY is incorrect at offset %d", ctx.ip)
}
}
}
if !jumps.IsSubset(instrs) {
return errors.New("some jumps are done to wrong offsets (not to instruction boundary)")
}
if methods != nil && !methods.IsSubset(instrs) {
return errors.New("some methods point to wrong offsets (not to instruction boundary)")
}
return nil
}

153
pkg/vm/contract_checks_test.go
View file

@ -5,8 +5,12 @@ import (
"testing"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/util/bitfield"
"github.com/nspcc-dev/neo-go/pkg/vm/emit"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
@ -115,3 +119,152 @@ func TestIsMultiSigContract(t *testing.T) {
assert.False(t, IsMultiSigContract(prog))
})
}
func TestIsScriptCorrect(t *testing.T) {
w := io.NewBufBinWriter()
emit.String(w.BinWriter, "something")
jmpOff := w.Len()
emit.Opcodes(w.BinWriter, opcode.JMP, opcode.Opcode(-jmpOff))
retOff := w.Len()
emit.Opcodes(w.BinWriter, opcode.RET)
jmplOff := w.Len()
emit.Opcodes(w.BinWriter, opcode.JMPL, opcode.Opcode(0xff), opcode.Opcode(0xff), opcode.Opcode(0xff), opcode.Opcode(0xff))
tryOff := w.Len()
emit.Opcodes(w.BinWriter, opcode.TRY, opcode.Opcode(3), opcode.Opcode(0xfb)) // -5
trylOff := w.Len()
emit.Opcodes(w.BinWriter, opcode.TRYL, opcode.Opcode(0xfd), opcode.Opcode(0xff), opcode.Opcode(0xff), opcode.Opcode(0xff),
opcode.Opcode(9), opcode.Opcode(0), opcode.Opcode(0), opcode.Opcode(0))
istypeOff := w.Len()
emit.Opcodes(w.BinWriter, opcode.ISTYPE, opcode.Opcode(stackitem.IntegerT))
pushOff := w.Len()
emit.String(w.BinWriter, "else")
good := w.Bytes()
getScript := func() []byte {
s := make([]byte, len(good))
copy(s, good)
return s
}
t.Run("good", func(t *testing.T) {
require.NoError(t, IsScriptCorrect(good, nil))
})
t.Run("bad instruction", func(t *testing.T) {
bad := getScript()
bad[retOff] = 0xff
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("out of bounds JMP 1", func(t *testing.T) {
bad := getScript()
bad[jmpOff+1] = 0x80 // -128
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("out of bounds JMP 2", func(t *testing.T) {
bad := getScript()
bad[jmpOff+1] = 0x7f
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("bad JMP offset 1", func(t *testing.T) {
bad := getScript()
bad[jmpOff+1] = 0xff // into "something"
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("bad JMP offset 2", func(t *testing.T) {
bad := getScript()
bad[jmpOff+1] = byte(pushOff - jmpOff + 1)
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("out of bounds JMPL 1", func(t *testing.T) {
bad := getScript()
bad[jmplOff+1] = byte(-jmplOff - 1)
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("out of bounds JMPL 1", func(t *testing.T) {
bad := getScript()
bad[jmplOff+1] = byte(len(bad) - jmplOff)
bad[jmplOff+2] = 0
bad[jmplOff+3] = 0
bad[jmplOff+4] = 0
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("bad JMPL offset", func(t *testing.T) {
bad := getScript()
bad[jmplOff+1] = 0xfe // into JMP
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("out of bounds TRY 1", func(t *testing.T) {
bad := getScript()
bad[tryOff+1] = byte(-tryOff - 1)
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("out of bounds TRY 2", func(t *testing.T) {
bad := getScript()
bad[tryOff+2] = byte(len(bad) - tryOff)
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("bad TRYL offset 1", func(t *testing.T) {
bad := getScript()
bad[trylOff+1] = byte(-(trylOff - jmpOff) - 1) // into "something"
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("bad TRYL offset 2", func(t *testing.T) {
bad := getScript()
bad[trylOff+5] = byte(len(bad) - trylOff - 1)
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("bad ISTYPE type", func(t *testing.T) {
bad := getScript()
bad[istypeOff+1] = byte(0xff)
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("bad ISTYPE type (Any)", func(t *testing.T) {
bad := getScript()
bad[istypeOff+1] = byte(stackitem.AnyT)
require.Error(t, IsScriptCorrect(bad, nil))
})
t.Run("good NEWARRAY_T type", func(t *testing.T) {
bad := getScript()
bad[istypeOff] = byte(opcode.NEWARRAYT)
bad[istypeOff+1] = byte(stackitem.AnyT)
require.NoError(t, IsScriptCorrect(bad, nil))
})
t.Run("good methods", func(t *testing.T) {
methods := bitfield.New(len(good))
methods.Set(retOff)
methods.Set(tryOff)
methods.Set(pushOff)
require.NoError(t, IsScriptCorrect(good, methods))
})
t.Run("bad methods", func(t *testing.T) {
methods := bitfield.New(len(good))
methods.Set(retOff)
methods.Set(tryOff)
methods.Set(pushOff + 1)
require.Error(t, IsScriptCorrect(good, methods))
})
}

26
pkg/vm/vm.go
View file

@ -185,11 +185,11 @@ func (v *VM) PrintOps(out io.Writer) {
opcode.JMPEQL, opcode.JMPNEL,
opcode.JMPGTL, opcode.JMPGEL, opcode.JMPLEL, opcode.JMPLTL,
opcode.PUSHA, opcode.ENDTRY, opcode.ENDTRYL:
desc = v.getOffsetDesc(ctx, parameter)
desc = getOffsetDesc(ctx, parameter)
case opcode.TRY, opcode.TRYL:
catchP, finallyP := getTryParams(instr, parameter)
desc = fmt.Sprintf("catch %s, finally %s",
v.getOffsetDesc(ctx, catchP), v.getOffsetDesc(ctx, finallyP))
getOffsetDesc(ctx, catchP), getOffsetDesc(ctx, finallyP))
case opcode.INITSSLOT:
desc = fmt.Sprint(parameter[0])
case opcode.CONVERT, opcode.ISTYPE:
@ -226,8 +226,8 @@ func (v *VM) PrintOps(out io.Writer) {
w.Flush()
}
func (v *VM) getOffsetDesc(ctx *Context, parameter []byte) string {
offset, rOffset, err := v.calcJumpOffset(ctx, parameter)
func getOffsetDesc(ctx *Context, parameter []byte) string {
offset, rOffset, err := calcJumpOffset(ctx, parameter)
if err != nil {
return fmt.Sprintf("ERROR: %v", err)
}
@ -552,7 +552,7 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
v.estack.PushVal(parameter)
case opcode.PUSHA:
n := v.getJumpOffset(ctx, parameter)
n := getJumpOffset(ctx, parameter)
ptr := stackitem.NewPointerWithHash(n, ctx.prog, ctx.ScriptHash())
v.estack.PushVal(ptr)
@ -1249,7 +1249,7 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
opcode.JMPEQ, opcode.JMPEQL, opcode.JMPNE, opcode.JMPNEL,
opcode.JMPGT, opcode.JMPGTL, opcode.JMPGE, opcode.JMPGEL,
opcode.JMPLT, opcode.JMPLTL, opcode.JMPLE, opcode.JMPLEL:
offset := v.getJumpOffset(ctx, parameter)
offset := getJumpOffset(ctx, parameter)
cond := true
switch op {
case opcode.JMP, opcode.JMPL:
@ -1268,7 +1268,7 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
case opcode.CALL, opcode.CALLL:
// Note: jump offset must be calculated regarding to new context,
// but it is cloned and thus has the same script and instruction pointer.
v.call(ctx, v.getJumpOffset(ctx, parameter))
v.call(ctx, getJumpOffset(ctx, parameter))
case opcode.CALLA:
ptr := v.estack.Pop().Item().(*stackitem.Pointer)
@ -1406,8 +1406,8 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
if ctx.tryStack.Len() >= MaxTryNestingDepth {
panic("maximum TRY depth exceeded")
}
cOffset := v.getJumpOffset(ctx, catchP)
fOffset := v.getJumpOffset(ctx, finallyP)
cOffset := getJumpOffset(ctx, catchP)
fOffset := getJumpOffset(ctx, finallyP)
if cOffset == ctx.ip && fOffset == ctx.ip {
panic("invalid offset for TRY*")
} else if cOffset == ctx.ip {
@ -1423,7 +1423,7 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
if eCtx.State == eFinally {
panic("invalid exception handling state during ENDTRY*")
}
eOffset := v.getJumpOffset(ctx, parameter)
eOffset := getJumpOffset(ctx, parameter)
if eCtx.HasFinally() {
eCtx.State = eFinally
eCtx.EndOffset = eOffset
@ -1527,8 +1527,8 @@ func (v *VM) call(ctx *Context, offset int) {
// to a which JMP should be performed.
// parameter should have length either 1 or 4 and
// is interpreted as little-endian.
func (v *VM) getJumpOffset(ctx *Context, parameter []byte) int {
offset, _, err := v.calcJumpOffset(ctx, parameter)
func getJumpOffset(ctx *Context, parameter []byte) int {
offset, _, err := calcJumpOffset(ctx, parameter)
if err != nil {
panic(err)
}
@ -1537,7 +1537,7 @@ func (v *VM) getJumpOffset(ctx *Context, parameter []byte) int {
// calcJumpOffset returns absolute and relative offset of JMP/CALL/TRY instructions
// either in short (1-byte) or long (4-byte) form.
func (v *VM) calcJumpOffset(ctx *Context, parameter []byte) (int, int, error) {
func calcJumpOffset(ctx *Context, parameter []byte) (int, int, error) {
var rOffset int32
switch l := len(parameter); l {
case 1: