diff --git a/rlp/decode.go b/rlp/decode.go index 8121ab2e72..ac04d5d569 100644 --- a/rlp/decode.go +++ b/rlp/decode.go @@ -220,20 +220,51 @@ func decodeBigIntNoPtr(s *Stream, val reflect.Value) error { } func decodeBigInt(s *Stream, val reflect.Value) error { - b, err := s.Bytes() - if err != nil { + var buffer []byte + kind, size, err := s.Kind() + switch { + case err != nil: return wrapStreamError(err, val.Type()) + case kind == List: + return wrapStreamError(ErrExpectedString, val.Type()) + case kind == Byte: + buffer = s.uintbuf[:1] + buffer[0] = s.byteval + s.kind = -1 // re-arm Kind + case size == 0: + // Avoid zero-length read. + s.kind = -1 + case size <= uint64(len(s.uintbuf)): + // For integers smaller than s.uintbuf, allocating a buffer + // can be avoided. + buffer = s.uintbuf[:size] + if err := s.readFull(buffer); err != nil { + return wrapStreamError(err, val.Type()) + } + // Reject inputs where single byte encoding should have been used. + if size == 1 && buffer[0] < 128 { + return wrapStreamError(ErrCanonSize, val.Type()) + } + default: + // For large integers, a temporary buffer is needed. + buffer = make([]byte, size) + if err := s.readFull(buffer); err != nil { + return wrapStreamError(err, val.Type()) + } } + + // Reject leading zero bytes. + if len(buffer) > 0 && buffer[0] == 0 { + return wrapStreamError(ErrCanonInt, val.Type()) + } + + // Set the integer bytes. i := val.Interface().(*big.Int) if i == nil { i = new(big.Int) val.Set(reflect.ValueOf(i)) } - // Reject leading zero bytes. - if len(b) > 0 && b[0] == 0 { - return wrapStreamError(ErrCanonInt, val.Type()) - } - i.SetBytes(b) + i.SetBytes(buffer) return nil } @@ -563,7 +594,7 @@ type Stream struct { size uint64 // size of value ahead kinderr error // error from last readKind stack []uint64 // list sizes - uintbuf [8]byte // auxiliary buffer for integer decoding + uintbuf [32]byte // auxiliary buffer for integer decoding kind Kind // kind of value ahead byteval byte // value of single byte in type tag limited bool // true if input limit is in effect @@ -817,7 +848,7 @@ func (s *Stream) Reset(r io.Reader, inputLimit uint64) { s.kind = -1 s.kinderr = nil s.byteval = 0 - s.uintbuf = [8]byte{} + s.uintbuf = [32]byte{} } // Kind returns the kind and size of the next value in the @@ -927,17 +958,20 @@ func (s *Stream) readUint(size byte) (uint64, error) { b, err := s.readByte() return uint64(b), err default: + buffer := s.uintbuf[:8] + for i := range buffer { + buffer[i] = 0 + } start := int(8 - size) - s.uintbuf = [8]byte{} - if err := s.readFull(s.uintbuf[start:]); err != nil { + if err := s.readFull(buffer[start:]); err != nil { return 0, err } - if s.uintbuf[start] == 0 { + if buffer[start] == 0 { // Note: readUint is also used to decode integer values. // The error needs to be adjusted to become ErrCanonInt in this case. return 0, ErrCanonSize } - return binary.BigEndian.Uint64(s.uintbuf[:]), nil + return binary.BigEndian.Uint64(buffer[:]), nil } } diff --git a/rlp/decode_test.go b/rlp/decode_test.go index 36d254e18e..7c3dafeac4 100644 --- a/rlp/decode_test.go +++ b/rlp/decode_test.go @@ -329,6 +329,11 @@ type recstruct struct { Child *recstruct `rlp:"nil"` } +type bigIntStruct struct { + I *big.Int + B string +} + type invalidNilTag struct { X []byte `rlp:"nil"` } @@ -405,10 +410,11 @@ type ignoredField struct { } var ( - veryBigInt = big.NewInt(0).Add( + veryBigInt = new(big.Int).Add( big.NewInt(0).Lsh(big.NewInt(0xFFFFFFFFFFFFFF), 16), big.NewInt(0xFFFF), ) + veryVeryBigInt = new(big.Int).Exp(veryBigInt, big.NewInt(8), nil) ) var decodeTests = []decodeTest{ @@ -479,12 +485,15 @@ var decodeTests = []decodeTest{ {input: "C0", ptr: new(string), error: "rlp: expected input string or byte for string"}, // big ints + {input: "80", ptr: new(*big.Int), value: big.NewInt(0)}, {input: "01", ptr: new(*big.Int), value: big.NewInt(1)}, {input: "89FFFFFFFFFFFFFFFFFF", ptr: new(*big.Int), value: veryBigInt}, + {input: "B848FFFFFFFFFFFFFFFFF800000000000000001BFFFFFFFFFFFFFFFFC8000000000000000045FFFFFFFFFFFFFFFFC800000000000000001BFFFFFFFFFFFFFFFFF8000000000000000001", ptr: new(*big.Int), value: veryVeryBigInt}, {input: "10", ptr: new(big.Int), value: *big.NewInt(16)}, // non-pointer also works {input: "C0", ptr: new(*big.Int), error: "rlp: expected input string or byte for *big.Int"}, - {input: "820001", ptr: new(big.Int), error: "rlp: non-canonical integer (leading zero bytes) for *big.Int"}, - {input: "8105", ptr: new(big.Int), error: "rlp: non-canonical size information for *big.Int"}, + {input: "00", ptr: new(*big.Int), error: "rlp: non-canonical integer (leading zero bytes) for *big.Int"}, + {input: "820001", ptr: new(*big.Int), error: "rlp: non-canonical integer (leading zero bytes) for *big.Int"}, + {input: "8105", ptr: new(*big.Int), error: "rlp: non-canonical size information for *big.Int"}, // structs { @@ -497,6 +506,13 @@ var decodeTests = []decodeTest{ ptr: new(recstruct), value: recstruct{1, &recstruct{2, &recstruct{3, nil}}}, }, + { + // This checks that empty big.Int works correctly in struct context. It's easy to + // miss the update of s.kind for this case, so it needs its own test. + input: "C58083343434", + ptr: new(bigIntStruct), + value: bigIntStruct{new(big.Int), "444"}, + }, // struct errors { diff --git a/rlp/encode_test.go b/rlp/encode_test.go index 08a2a84c62..25d4aac267 100644 --- a/rlp/encode_test.go +++ b/rlp/encode_test.go @@ -131,6 +131,14 @@ var encTests = []encTest{ val: big.NewInt(0).SetBytes(unhex("010000000000000000000000000000000000000000000000000000000000000000")), output: "A1010000000000000000000000000000000000000000000000000000000000000000", }, + { + val: veryBigInt, + output: "89FFFFFFFFFFFFFFFFFF", + }, + { + val: veryVeryBigInt, + output: "B848FFFFFFFFFFFFFFFFF800000000000000001BFFFFFFFFFFFFFFFFC8000000000000000045FFFFFFFFFFFFFFFFC800000000000000001BFFFFFFFFFFFFFFFFF8000000000000000001", + }, // non-pointer big.Int {val: *big.NewInt(0), output: "80"},