rlp: reject non-minimal input strings
Input strings of length 1 containing a byte < 56 are non-minimal and should be encoded as a single byte instead. Reject such strings.
This commit is contained in:
Felix Lange
parent
6e9f8035a1
commit
1e2c93aa2d
@ -305,10 +305,11 @@ func decodeByteSlice(s *Stream, val reflect.Value) error {
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return decodeListSlice(s, val, decodeUint)
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}
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b, err := s.Bytes()
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if err == nil {
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val.SetBytes(b)
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if err != nil {
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return wrapStreamError(err, val.Type())
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}
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return err
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val.SetBytes(b)
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return nil
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}
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func decodeByteArray(s *Stream, val reflect.Value) error {
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@ -333,6 +334,10 @@ func decodeByteArray(s *Stream, val reflect.Value) error {
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return err
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}
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zero(val, int(size))
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// Reject cases where single byte encoding should have been used.
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if size == 1 && slice[0] < 56 {
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return wrapStreamError(ErrCanonSize, val.Type())
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}
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case List:
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return decodeListArray(s, val, decodeUint)
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}
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@ -477,7 +482,7 @@ var (
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// Actual Errors
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ErrExpectedString = errors.New("rlp: expected String or Byte")
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ErrExpectedList = errors.New("rlp: expected List")
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ErrCanonInt = errors.New("rlp: non-canonical (leading zero bytes) integer")
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ErrCanonInt = errors.New("rlp: non-canonical integer format")
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ErrCanonSize = errors.New("rlp: non-canonical size information")
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ErrElemTooLarge = errors.New("rlp: element is larger than containing list")
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ErrValueTooLarge = errors.New("rlp: value size exceeds available input length")
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@ -576,6 +581,9 @@ func (s *Stream) Bytes() ([]byte, error) {
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if err = s.readFull(b); err != nil {
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return nil, err
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}
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if size == 1 && b[0] < 56 {
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return nil, ErrCanonSize
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}
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return b, nil
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default:
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return nil, ErrExpectedString
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@ -631,11 +639,17 @@ func (s *Stream) uint(maxbits int) (uint64, error) {
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return 0, errUintOverflow
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}
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v, err := s.readUint(byte(size))
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if err == ErrCanonSize {
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switch {
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case err == ErrCanonSize:
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// Adjust error because we're not reading a size right now.
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err = ErrCanonInt
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return 0, ErrCanonInt
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case err != nil:
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return 0, err
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case size > 0 && v < 56:
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return 0, ErrCanonSize
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default:
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return v, nil
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}
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return v, err
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default:
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return 0, ErrExpectedString
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}
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@ -93,12 +93,16 @@ func TestStreamErrors(t *testing.T) {
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{"00", calls{"ListEnd"}, nil, errNotInList},
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{"C401020304", calls{"List", "Uint", "ListEnd"}, nil, errNotAtEOL},
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// Leading zero bytes are rejected when reading integers.
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// Non-canonical integers (e.g. leading zero bytes).
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{"00", calls{"Uint"}, nil, ErrCanonInt},
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{"820002", calls{"Uint"}, nil, ErrCanonInt},
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{"8133", calls{"Uint"}, nil, ErrCanonSize},
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{"8156", calls{"Uint"}, nil, nil},
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// Size tags must use the smallest possible encoding.
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// Leading zero bytes in the size tag are also rejected.
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{"8100", calls{"Uint"}, nil, ErrCanonSize},
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{"8100", calls{"Bytes"}, nil, ErrCanonSize},
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{"B800", calls{"Kind"}, withoutInputLimit, ErrCanonSize},
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{"B90000", calls{"Kind"}, withoutInputLimit, ErrCanonSize},
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{"B90055", calls{"Kind"}, withoutInputLimit, ErrCanonSize},
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@ -112,7 +116,7 @@ func TestStreamErrors(t *testing.T) {
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{"", calls{"Kind"}, nil, io.EOF},
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{"", calls{"Uint"}, nil, io.EOF},
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{"", calls{"List"}, nil, io.EOF},
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{"8105", calls{"Uint", "Uint"}, nil, io.EOF},
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{"8158", calls{"Uint", "Uint"}, nil, io.EOF},
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{"C0", calls{"List", "ListEnd", "List"}, nil, io.EOF},
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// Input limit errors.
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@ -129,11 +133,11 @@ func TestStreamErrors(t *testing.T) {
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// down toward zero in Stream.remaining, reading too far can overflow
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// remaining to a large value, effectively disabling the limit.
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{"C40102030401", calls{"Raw", "Uint"}, withCustomInputLimit(5), io.EOF},
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{"C4010203048102", calls{"Raw", "Uint"}, withCustomInputLimit(6), ErrValueTooLarge},
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{"C4010203048158", calls{"Raw", "Uint"}, withCustomInputLimit(6), ErrValueTooLarge},
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// Check that the same calls are fine without a limit.
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{"C40102030401", calls{"Raw", "Uint"}, withoutInputLimit, nil},
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{"C4010203048102", calls{"Raw", "Uint"}, withoutInputLimit, nil},
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{"C4010203048158", calls{"Raw", "Uint"}, withoutInputLimit, nil},
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// Unexpected EOF. This only happens when there is
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// no input limit, so the reader needs to be 'dumbed down'.
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@ -295,13 +299,13 @@ var decodeTests = []decodeTest{
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// integers
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{input: "05", ptr: new(uint32), value: uint32(5)},
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{input: "80", ptr: new(uint32), value: uint32(0)},
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{input: "8105", ptr: new(uint32), value: uint32(5)},
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{input: "820505", ptr: new(uint32), value: uint32(0x0505)},
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{input: "83050505", ptr: new(uint32), value: uint32(0x050505)},
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{input: "8405050505", ptr: new(uint32), value: uint32(0x05050505)},
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{input: "850505050505", ptr: new(uint32), error: "rlp: input string too long for uint32"},
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{input: "C0", ptr: new(uint32), error: "rlp: expected input string or byte for uint32"},
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{input: "00", ptr: new(uint32), error: "rlp: non-canonical integer (leading zero bytes) for uint32"},
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{input: "8105", ptr: new(uint32), error: "rlp: non-canonical size information for uint32"},
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{input: "820004", ptr: new(uint32), error: "rlp: non-canonical integer (leading zero bytes) for uint32"},
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{input: "B8020004", ptr: new(uint32), error: "rlp: non-canonical size information for uint32"},
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@ -319,10 +323,16 @@ var decodeTests = []decodeTest{
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// byte slices
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{input: "01", ptr: new([]byte), value: []byte{1}},
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{input: "80", ptr: new([]byte), value: []byte{}},
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{input: "8D6162636465666768696A6B6C6D", ptr: new([]byte), value: []byte("abcdefghijklm")},
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{input: "C0", ptr: new([]byte), value: []byte{}},
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{input: "C3010203", ptr: new([]byte), value: []byte{1, 2, 3}},
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{
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input: "8105",
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ptr: new([]byte),
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error: "rlp: non-canonical size information for []uint8",
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},
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{
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input: "C3820102",
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ptr: new([]byte),
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@ -346,10 +356,15 @@ var decodeTests = []decodeTest{
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ptr: new([5]byte),
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error: "rlp: input string too long for [5]uint8",
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},
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{
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input: "8105",
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ptr: new([5]byte),
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error: "rlp: non-canonical size information for [5]uint8",
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},
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// byte array reuse (should be zeroed)
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{input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
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{input: "8101", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: String
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{input: "01", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: String
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{input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
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{input: "01", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: Byte
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{input: "C3010203", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 0, 0}},
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@ -369,9 +384,10 @@ var decodeTests = []decodeTest{
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// big ints
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{input: "01", ptr: new(*big.Int), value: big.NewInt(1)},
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{input: "89FFFFFFFFFFFFFFFFFF", ptr: new(*big.Int), value: veryBigInt},
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{input: "820001", ptr: new(big.Int), error: "rlp: non-canonical integer (leading zero bytes) for *big.Int"},
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{input: "10", ptr: new(big.Int), value: *big.NewInt(16)}, // non-pointer also works
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{input: "C0", ptr: new(*big.Int), error: "rlp: expected input string or byte for *big.Int"},
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{input: "820001", ptr: new(big.Int), error: "rlp: non-canonical integer (leading zero bytes) for *big.Int"},
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{input: "8105", ptr: new(big.Int), error: "rlp: non-canonical size information for *big.Int"},
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// structs
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{input: "C0", ptr: new(simplestruct), value: simplestruct{0, ""}},
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@ -404,7 +420,7 @@ var decodeTests = []decodeTest{
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{input: "80", ptr: new(*uint), value: (*uint)(nil)},
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{input: "C0", ptr: new(*uint), value: (*uint)(nil)},
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{input: "07", ptr: new(*uint), value: uintp(7)},
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{input: "8108", ptr: new(*uint), value: uintp(8)},
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{input: "8158", ptr: new(*uint), value: uintp(0x58)},
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{input: "C109", ptr: new(*[]uint), value: &[]uint{9}},
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{input: "C58403030303", ptr: new(*[][]byte), value: &[][]byte{{3, 3, 3, 3}}},
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