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Merge pull request #15770 from holiman/abi_nostruct

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accounts/abi: add another unpack interface
This commit is contained in:
Martin Holst Swende 2018-02-21 15:14:07 +01:00 committed by GitHub
commit f54506ccf8
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 171 additions and 68 deletions
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6
accounts/abi/abi.go
View File

@ -136,11 +136,11 @@ func (abi *ABI) UnmarshalJSON(data []byte) error {
// MethodById looks up a method by the 4-byte id
// returns nil if none found
func (abi *ABI) MethodById(sigdata []byte) *Method {
func (abi *ABI) MethodById(sigdata []byte) (*Method, error) {
for _, method := range abi.Methods {
if bytes.Equal(method.Id(), sigdata[:4]) {
return &method
return &method, nil
}
}
return nil
return nil, fmt.Errorf("no method with id: %#x", sigdata[:4])
}

6
accounts/abi/abi_test.go
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@ -689,7 +689,11 @@ func TestABI_MethodById(t *testing.T) {
}
for name, m := range abi.Methods {
a := fmt.Sprintf("%v", m)
b := fmt.Sprintf("%v", abi.MethodById(m.Id()))
m2, err := abi.MethodById(m.Id())
if err != nil {
t.Fatalf("Failed to look up ABI method: %v", err)
}
b := fmt.Sprintf("%v", m2)
if a != b {
t.Errorf("Method %v (id %v) not 'findable' by id in ABI", name, common.ToHex(m.Id()))
}

116
accounts/abi/argument.go
View File

@ -67,6 +67,17 @@ func (arguments Arguments) LengthNonIndexed() int {
return out
}
// NonIndexed returns the arguments with indexed arguments filtered out
func (arguments Arguments) NonIndexed() Arguments {
var ret []Argument
for _, arg := range arguments {
if !arg.Indexed {
ret = append(ret, arg)
}
}
return ret
}
// isTuple returns true for non-atomic constructs, like (uint,uint) or uint[]
func (arguments Arguments) isTuple() bool {
return len(arguments) > 1
@ -74,21 +85,25 @@ func (arguments Arguments) isTuple() bool {
// Unpack performs the operation hexdata -> Go format
func (arguments Arguments) Unpack(v interface{}, data []byte) error {
if arguments.isTuple() {
return arguments.unpackTuple(v, data)
}
return arguments.unpackAtomic(v, data)
}
func (arguments Arguments) unpackTuple(v interface{}, output []byte) error {
// make sure the passed value is arguments pointer
valueOf := reflect.ValueOf(v)
if reflect.Ptr != valueOf.Kind() {
if reflect.Ptr != reflect.ValueOf(v).Kind() {
return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
}
marshalledValues, err := arguments.UnpackValues(data)
if err != nil {
return err
}
if arguments.isTuple() {
return arguments.unpackTuple(v, marshalledValues)
}
return arguments.unpackAtomic(v, marshalledValues)
}
func (arguments Arguments) unpackTuple(v interface{}, marshalledValues []interface{}) error {
var (
value = valueOf.Elem()
value = reflect.ValueOf(v).Elem()
typ = value.Type()
kind = value.Kind()
)
@ -110,30 +125,9 @@ func (arguments Arguments) unpackTuple(v interface{}, output []byte) error {
exists[field] = true
}
}
// `i` counts the nonindexed arguments.
// `j` counts the number of complex types.
// both `i` and `j` are used to to correctly compute `data` offset.
for i, arg := range arguments.NonIndexed() {
i, j := -1, 0
for _, arg := range arguments {
if arg.Indexed {
// can't read, continue
continue
}
i++
marshalledValue, err := toGoType((i+j)*32, arg.Type, output)
if err != nil {
return err
}
if arg.Type.T == ArrayTy {
// combined index ('i' + 'j') need to be adjusted only by size of array, thus
// we need to decrement 'j' because 'i' was incremented
j += arg.Type.Size - 1
}
reflectValue := reflect.ValueOf(marshalledValue)
reflectValue := reflect.ValueOf(marshalledValues[i])
switch kind {
case reflect.Struct:
@ -166,34 +160,52 @@ func (arguments Arguments) unpackTuple(v interface{}, output []byte) error {
}
// unpackAtomic unpacks ( hexdata -> go ) a single value
func (arguments Arguments) unpackAtomic(v interface{}, output []byte) error {
// make sure the passed value is arguments pointer
valueOf := reflect.ValueOf(v)
if reflect.Ptr != valueOf.Kind() {
return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
func (arguments Arguments) unpackAtomic(v interface{}, marshalledValues []interface{}) error {
if len(marshalledValues) != 1 {
return fmt.Errorf("abi: wrong length, expected single value, got %d", len(marshalledValues))
}
arg := arguments[0]
if arg.Indexed {
return fmt.Errorf("abi: attempting to unpack indexed variable into element.")
}
value := valueOf.Elem()
marshalledValue, err := toGoType(0, arg.Type, output)
if err != nil {
return err
}
return set(value, reflect.ValueOf(marshalledValue), arg)
elem := reflect.ValueOf(v).Elem()
reflectValue := reflect.ValueOf(marshalledValues[0])
return set(elem, reflectValue, arguments.NonIndexed()[0])
}
// Unpack performs the operation Go format -> Hexdata
// UnpackValues can be used to unpack ABI-encoded hexdata according to the ABI-specification,
// without supplying a struct to unpack into. Instead, this method returns a list containing the
// values. An atomic argument will be a list with one element.
func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error) {
retval := make([]interface{}, 0, arguments.LengthNonIndexed())
virtualArgs := 0
for index, arg := range arguments.NonIndexed() {
marshalledValue, err := toGoType((index+virtualArgs)*32, arg.Type, data)
if arg.Type.T == ArrayTy {
// If we have a static array, like [3]uint256, these are coded as
// just like uint256,uint256,uint256.
// This means that we need to add two 'virtual' arguments when
// we count the index from now on
virtualArgs += arg.Type.Size - 1
}
if err != nil {
return nil, err
}
retval = append(retval, marshalledValue)
}
return retval, nil
}
// PackValues performs the operation Go format -> Hexdata
// It is the semantic opposite of UnpackValues
func (arguments Arguments) PackValues(args []interface{}) ([]byte, error) {
return arguments.Pack(args...)
}
// Pack performs the operation Go format -> Hexdata
func (arguments Arguments) Pack(args ...interface{}) ([]byte, error) {
// Make sure arguments match up and pack them
abiArgs := arguments
if len(args) != len(abiArgs) {
return nil, fmt.Errorf("argument count mismatch: %d for %d", len(args), len(abiArgs))
}
// variable input is the output appended at the end of packed
// output. This is used for strings and bytes types input.
var variableInput []byte
@ -207,7 +219,6 @@ func (arguments Arguments) Pack(args ...interface{}) ([]byte, error) {
inputOffset += 32
}
}
var ret []byte
for i, a := range args {
input := abiArgs[i]
@ -216,7 +227,6 @@ func (arguments Arguments) Pack(args ...interface{}) ([]byte, error) {
if err != nil {
return nil, err
}
// check for a slice type (string, bytes, slice)
if input.Type.requiresLengthPrefix() {
// calculate the offset

39
accounts/abi/unpack.go
View File

@ -95,6 +95,9 @@ func readFixedBytes(t Type, word []byte) (interface{}, error) {
// iteratively unpack elements
func forEachUnpack(t Type, output []byte, start, size int) (interface{}, error) {
if size < 0 {
return nil, fmt.Errorf("cannot marshal input to array, size is negative (%d)", size)
}
if start+32*size > len(output) {
return nil, fmt.Errorf("abi: cannot marshal in to go array: offset %d would go over slice boundary (len=%d)", len(output), start+32*size)
}
@ -181,16 +184,32 @@ func toGoType(index int, t Type, output []byte) (interface{}, error) {
// interprets a 32 byte slice as an offset and then determines which indice to look to decode the type.
func lengthPrefixPointsTo(index int, output []byte) (start int, length int, err error) {
offset := int(binary.BigEndian.Uint64(output[index+24 : index+32]))
if offset+32 > len(output) {
return 0, 0, fmt.Errorf("abi: cannot marshal in to go slice: offset %d would go over slice boundary (len=%d)", len(output), offset+32)
}
length = int(binary.BigEndian.Uint64(output[offset+24 : offset+32]))
if offset+32+length > len(output) {
return 0, 0, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32+length)
}
start = offset + 32
bigOffsetEnd := big.NewInt(0).SetBytes(output[index : index+32])
bigOffsetEnd.Add(bigOffsetEnd, common.Big32)
outputLength := big.NewInt(int64(len(output)))
//fmt.Printf("LENGTH PREFIX INFO: \nsize: %v\noffset: %v\nstart: %v\n", length, offset, start)
if bigOffsetEnd.Cmp(outputLength) > 0 {
return 0, 0, fmt.Errorf("abi: cannot marshal in to go slice: offset %v would go over slice boundary (len=%v)", bigOffsetEnd, outputLength)
}
if bigOffsetEnd.BitLen() > 63 {
return 0, 0, fmt.Errorf("abi offset larger than int64: %v", bigOffsetEnd)
}
offsetEnd := int(bigOffsetEnd.Uint64())
lengthBig := big.NewInt(0).SetBytes(output[offsetEnd-32 : offsetEnd])
totalSize := big.NewInt(0)
totalSize.Add(totalSize, bigOffsetEnd)
totalSize.Add(totalSize, lengthBig)
if totalSize.BitLen() > 63 {
return 0, 0, fmt.Errorf("abi length larger than int64: %v", totalSize)
}
if totalSize.Cmp(outputLength) > 0 {
return 0, 0, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %v require %v", outputLength, totalSize)
}
start = int(bigOffsetEnd.Uint64())
length = int(lengthBig.Uint64())
return
}

72
accounts/abi/unpack_test.go
View File

@ -130,7 +130,7 @@ var unpackTests = []unpackTest{
{
def: `[{"type": "bytes32"}]`,
enc: "0100000000000000000000000000000000000000000000000000000000000000",
want: common.HexToHash("0100000000000000000000000000000000000000000000000000000000000000"),
want: [32]byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
},
{
def: `[{"type": "function"}]`,
@ -683,3 +683,73 @@ func TestUnmarshal(t *testing.T) {
t.Fatal("expected error:", err)
}
}
func TestOOMMaliciousInput(t *testing.T) {
oomTests := []unpackTest{
{
def: `[{"type": "uint8[]"}]`,
enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
"0000000000000000000000000000000000000000000000000000000000000003" + // num elems
"0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
"0000000000000000000000000000000000000000000000000000000000000002", // elem 2
},
{ // Length larger than 64 bits
def: `[{"type": "uint8[]"}]`,
enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
"00ffffffffffffffffffffffffffffffffffffffffffffff0000000000000002" + // num elems
"0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
"0000000000000000000000000000000000000000000000000000000000000002", // elem 2
},
{ // Offset very large (over 64 bits)
def: `[{"type": "uint8[]"}]`,
enc: "00ffffffffffffffffffffffffffffffffffffffffffffff0000000000000020" + // offset
"0000000000000000000000000000000000000000000000000000000000000002" + // num elems
"0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
"0000000000000000000000000000000000000000000000000000000000000002", // elem 2
},
{ // Offset very large (below 64 bits)
def: `[{"type": "uint8[]"}]`,
enc: "0000000000000000000000000000000000000000000000007ffffffffff00020" + // offset
"0000000000000000000000000000000000000000000000000000000000000002" + // num elems
"0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
"0000000000000000000000000000000000000000000000000000000000000002", // elem 2
},
{ // Offset negative (as 64 bit)
def: `[{"type": "uint8[]"}]`,
enc: "000000000000000000000000000000000000000000000000f000000000000020" + // offset
"0000000000000000000000000000000000000000000000000000000000000002" + // num elems
"0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
"0000000000000000000000000000000000000000000000000000000000000002", // elem 2
},
{ // Negative length
def: `[{"type": "uint8[]"}]`,
enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
"000000000000000000000000000000000000000000000000f000000000000002" + // num elems
"0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
"0000000000000000000000000000000000000000000000000000000000000002", // elem 2
},
{ // Very large length
def: `[{"type": "uint8[]"}]`,
enc: "0000000000000000000000000000000000000000000000000000000000000020" + // offset
"0000000000000000000000000000000000000000000000007fffffffff000002" + // num elems
"0000000000000000000000000000000000000000000000000000000000000001" + // elem 1
"0000000000000000000000000000000000000000000000000000000000000002", // elem 2
},
}
for i, test := range oomTests {
def := fmt.Sprintf(`[{ "name" : "method", "outputs": %s}]`, test.def)
abi, err := JSON(strings.NewReader(def))
if err != nil {
t.Fatalf("invalid ABI definition %s: %v", def, err)
}
encb, err := hex.DecodeString(test.enc)
if err != nil {
t.Fatalf("invalid hex: %s" + test.enc)
}
_, err = abi.Methods["method"].Outputs.UnpackValues(encb)
if err == nil {
t.Fatalf("Expected error on malicious input, test %d", i)
}
}
}