Test for data corruption in datafile decoding (#99)

* internal/data: move codec to own subpackage

* internal/data/codec: check & test nil Entry Decode

* internal/data/decoder: test for short prefix error

* internal/data/codec: test invalid key & value sizes

* internal/data/codec: check & test for truncated data

* interna/data/codec: use assert for tests
This commit is contained in:
Ignacio Hagopian 2019-09-16 09:29:08 -03:00 committed by GitHub
parent 5be114adab
commit f17187a5c7
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 192 additions and 65 deletions

@ -1,7 +1,6 @@
package data
package codec
import (
"bufio"
"encoding/binary"
"io"
@ -9,59 +8,12 @@ import (
"github.com/prologic/bitcask/internal"
)
const (
keySize = 4
valueSize = 8
checksumSize = 4
)
var (
// ErrInvalidKeyOrValueSize indicates a serialized key/value size
// which is greater than specified limit
ErrInvalidKeyOrValueSize = errors.New("key/value size is invalid")
errInvalidKeyOrValueSize = errors.New("key/value size is invalid")
errCantDecodeOnNilEntry = errors.New("can't decode on nil entry")
errTruncatedData = errors.New("data is truncated")
)
// NewEncoder creates a streaming Entry encoder.
func NewEncoder(w io.Writer) *Encoder {
return &Encoder{w: bufio.NewWriter(w)}
}
// Encoder wraps an underlying io.Writer and allows you to stream
// Entry encodings on it.
type Encoder struct {
w *bufio.Writer
}
// Encode takes any Entry and streams it to the underlying writer.
// Messages are framed with a key-length and value-length prefix.
func (e *Encoder) Encode(msg internal.Entry) (int64, error) {
var bufKeyValue = make([]byte, keySize+valueSize)
binary.BigEndian.PutUint32(bufKeyValue[:keySize], uint32(len(msg.Key)))
binary.BigEndian.PutUint64(bufKeyValue[keySize:keySize+valueSize], uint64(len(msg.Value)))
if _, err := e.w.Write(bufKeyValue); err != nil {
return 0, errors.Wrap(err, "failed writing key & value length prefix")
}
if _, err := e.w.Write(msg.Key); err != nil {
return 0, errors.Wrap(err, "failed writing key data")
}
if _, err := e.w.Write(msg.Value); err != nil {
return 0, errors.Wrap(err, "failed writing value data")
}
bufChecksumSize := bufKeyValue[:checksumSize]
binary.BigEndian.PutUint32(bufChecksumSize, msg.Checksum)
if _, err := e.w.Write(bufChecksumSize); err != nil {
return 0, errors.Wrap(err, "failed writing checksum data")
}
if err := e.w.Flush(); err != nil {
return 0, errors.Wrap(err, "failed flushing data")
}
return int64(keySize + valueSize + len(msg.Key) + len(msg.Value) + checksumSize), nil
}
// NewDecoder creates a streaming Entry decoder.
func NewDecoder(r io.Reader, maxKeySize uint32, maxValueSize uint64) *Decoder {
return &Decoder{
@ -81,6 +33,10 @@ type Decoder struct {
// Decode decodes the next Entry from the current stream
func (d *Decoder) Decode(v *internal.Entry) (int64, error) {
if v == nil {
return 0, errCantDecodeOnNilEntry
}
prefixBuf := make([]byte, keySize+valueSize)
_, err := io.ReadFull(d.r, prefixBuf)
@ -90,12 +46,12 @@ func (d *Decoder) Decode(v *internal.Entry) (int64, error) {
actualKeySize, actualValueSize, err := getKeyValueSizes(prefixBuf, d.maxKeySize, d.maxValueSize)
if err != nil {
return 0, errors.Wrap(err, "error while getting key/value serialized sizes")
return 0, err
}
buf := make([]byte, uint64(actualKeySize)+actualValueSize+checksumSize)
if _, err = io.ReadFull(d.r, buf); err != nil {
return 0, errors.Wrap(translateError(err), "failed reading saved data")
return 0, errTruncatedData
}
decodeWithoutPrefix(buf, actualKeySize, v)
@ -118,8 +74,9 @@ func getKeyValueSizes(buf []byte, maxKeySize uint32, maxValueSize uint64) (uint3
actualKeySize := binary.BigEndian.Uint32(buf[:keySize])
actualValueSize := binary.BigEndian.Uint64(buf[keySize:])
if actualKeySize > maxKeySize || actualValueSize > maxValueSize {
return 0, 0, ErrInvalidKeyOrValueSize
if actualKeySize > maxKeySize || actualValueSize > maxValueSize || actualKeySize == 0 {
return 0, 0, errInvalidKeyOrValueSize
}
return actualKeySize, actualValueSize, nil
@ -131,9 +88,12 @@ func decodeWithoutPrefix(buf []byte, valueOffset uint32, v *internal.Entry) {
v.Checksum = binary.BigEndian.Uint32(buf[len(buf)-checksumSize:])
}
func translateError(err error) error {
if err == io.EOF {
return io.ErrUnexpectedEOF
// IsCorruptedData indicates if the error correspondes to possible data corruption
func IsCorruptedData(err error) bool {
switch err {
case errCantDecodeOnNilEntry, errInvalidKeyOrValueSize, errTruncatedData:
return true
default:
return false
}
return err
}

@ -0,0 +1,109 @@
package codec
import (
"bytes"
"encoding/binary"
"io"
"testing"
"github.com/prologic/bitcask/internal"
"github.com/stretchr/testify/assert"
)
func TestDecodeOnNilEntry(t *testing.T) {
t.Parallel()
assert := assert.New(t)
decoder := NewDecoder(&bytes.Buffer{}, 1, 1)
_, err := decoder.Decode(nil)
if assert.Error(err) {
assert.Equal(errCantDecodeOnNilEntry, err)
}
}
func TestShortPrefix(t *testing.T) {
t.Parallel()
assert := assert.New(t)
maxKeySize, maxValueSize := uint32(10), uint64(20)
prefix := make([]byte, keySize+valueSize)
binary.BigEndian.PutUint32(prefix, 1)
binary.BigEndian.PutUint64(prefix[keySize:], 1)
truncBytesCount := 2
buf := bytes.NewBuffer(prefix[:keySize+valueSize-truncBytesCount])
decoder := NewDecoder(buf, maxKeySize, maxValueSize)
_, err := decoder.Decode(&internal.Entry{})
if assert.Error(err) {
assert.Equal(io.ErrUnexpectedEOF, err)
}
}
func TestInvalidValueKeySizes(t *testing.T) {
assert := assert.New(t)
maxKeySize, maxValueSize := uint32(10), uint64(20)
tests := []struct {
keySize uint32
valueSize uint64
name string
}{
{keySize: 0, valueSize: 5, name: "zero key size"}, //zero value size is correct for tombstones
{keySize: 11, valueSize: 5, name: "key size overflow"},
{keySize: 5, valueSize: 21, name: "value size overflow"},
{keySize: 11, valueSize: 21, name: "key and value size overflow"},
}
for i := range tests {
i := i
t.Run(tests[i].name, func(t *testing.T) {
t.Parallel()
prefix := make([]byte, keySize+valueSize)
binary.BigEndian.PutUint32(prefix, tests[i].keySize)
binary.BigEndian.PutUint64(prefix[keySize:], tests[i].valueSize)
buf := bytes.NewBuffer(prefix)
decoder := NewDecoder(buf, maxKeySize, maxValueSize)
_, err := decoder.Decode(&internal.Entry{})
if assert.Error(err) {
assert.Equal(errInvalidKeyOrValueSize, err)
}
})
}
}
func TestTruncatedData(t *testing.T) {
assert := assert.New(t)
maxKeySize, maxValueSize := uint32(10), uint64(20)
key := []byte("foo")
value := []byte("bar")
data := make([]byte, keySize+valueSize+len(key)+len(value)+checksumSize)
binary.BigEndian.PutUint32(data, uint32(len(key)))
binary.BigEndian.PutUint64(data[keySize:], uint64(len(value)))
copy(data[keySize+valueSize:], key)
copy(data[keySize+valueSize+len(key):], value)
copy(data[keySize+valueSize+len(key)+len(value):], bytes.Repeat([]byte("0"), checksumSize))
tests := []struct {
data []byte
name string
}{
{data: data[:keySize+valueSize+len(key)-1], name: "truncated key"},
{data: data[:keySize+valueSize+len(key)+len(value)-1], name: "truncated value"},
{data: data[:keySize+valueSize+len(key)+len(value)+checksumSize-1], name: "truncated checksum"},
}
for i := range tests {
i := i
t.Run(tests[i].name, func(t *testing.T) {
t.Parallel()
buf := bytes.NewBuffer(tests[i].data)
decoder := NewDecoder(buf, maxKeySize, maxValueSize)
_, err := decoder.Decode(&internal.Entry{})
if assert.Error(err) {
assert.Equal(errTruncatedData, err)
}
})
}
}

@ -0,0 +1,57 @@
package codec
import (
"bufio"
"encoding/binary"
"io"
"github.com/pkg/errors"
"github.com/prologic/bitcask/internal"
)
const (
keySize = 4
valueSize = 8
checksumSize = 4
)
// NewEncoder creates a streaming Entry encoder.
func NewEncoder(w io.Writer) *Encoder {
return &Encoder{w: bufio.NewWriter(w)}
}
// Encoder wraps an underlying io.Writer and allows you to stream
// Entry encodings on it.
type Encoder struct {
w *bufio.Writer
}
// Encode takes any Entry and streams it to the underlying writer.
// Messages are framed with a key-length and value-length prefix.
func (e *Encoder) Encode(msg internal.Entry) (int64, error) {
var bufKeyValue = make([]byte, keySize+valueSize)
binary.BigEndian.PutUint32(bufKeyValue[:keySize], uint32(len(msg.Key)))
binary.BigEndian.PutUint64(bufKeyValue[keySize:keySize+valueSize], uint64(len(msg.Value)))
if _, err := e.w.Write(bufKeyValue); err != nil {
return 0, errors.Wrap(err, "failed writing key & value length prefix")
}
if _, err := e.w.Write(msg.Key); err != nil {
return 0, errors.Wrap(err, "failed writing key data")
}
if _, err := e.w.Write(msg.Value); err != nil {
return 0, errors.Wrap(err, "failed writing value data")
}
bufChecksumSize := bufKeyValue[:checksumSize]
binary.BigEndian.PutUint32(bufChecksumSize, msg.Checksum)
if _, err := e.w.Write(bufChecksumSize); err != nil {
return 0, errors.Wrap(err, "failed writing checksum data")
}
if err := e.w.Flush(); err != nil {
return 0, errors.Wrap(err, "failed flushing data")
}
return int64(keySize + valueSize + len(msg.Key) + len(msg.Value) + checksumSize), nil
}

@ -8,6 +8,7 @@ import (
"github.com/pkg/errors"
"github.com/prologic/bitcask/internal"
"github.com/prologic/bitcask/internal/data/codec"
"golang.org/x/exp/mmap"
)
@ -41,8 +42,8 @@ type datafile struct {
ra *mmap.ReaderAt
w *os.File
offset int64
dec *Decoder
enc *Encoder
dec *codec.Decoder
enc *codec.Encoder
maxKeySize uint32
maxValueSize uint64
}
@ -81,8 +82,8 @@ func NewDatafile(path string, id int, readonly bool, maxKeySize uint32, maxValue
offset := stat.Size()
dec := NewDecoder(r, maxKeySize, maxValueSize)
enc := NewEncoder(w)
dec := codec.NewDecoder(r, maxKeySize, maxValueSize)
enc := codec.NewEncoder(w)
return &datafile{
id: id,
@ -168,7 +169,7 @@ func (df *datafile) ReadAt(index, size int64) (e internal.Entry, err error) {
return
}
DecodeEntry(b, &e, df.maxKeySize, df.maxValueSize)
codec.DecodeEntry(b, &e, df.maxKeySize, df.maxValueSize)
return
}