Repository navigation
Expand file tree
/
Copy pathbitrot.go
More file actions
238 lines (215 loc) · 7.26 KB
/
Copy pathbitrot.go
File metadata and controls
238 lines (215 loc) · 7.26 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
/*
* MinIO Cloud Storage, (C) 2018 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"bytes"
"crypto/sha256"
"encoding/hex"
"errors"
"fmt"
"hash"
"io"
"github.com/minio/highwayhash"
"github.com/minio/minio/cmd/logger"
"golang.org/x/crypto/blake2b"
)
// magic HH-256 key as HH-256 hash of the first 100 decimals of π as utf-8 string with a zero key.
var magicHighwayHash256Key = []byte("\x4b\xe7\x34\xfa\x8e\x23\x8a\xcd\x26\x3e\x83\xe6\xbb\x96\x85\x52\x04\x0f\x93\x5d\xa3\x9f\x44\x14\x97\xe0\x9d\x13\x22\xde\x36\xa0")
var bitrotAlgorithms = map[BitrotAlgorithm]string{
SHA256: "sha256",
BLAKE2b512: "blake2b",
HighwayHash256: "highwayhash256",
HighwayHash256S: "highwayhash256S",
}
// New returns a new hash.Hash calculating the given bitrot algorithm.
func (a BitrotAlgorithm) New() hash.Hash {
switch a {
case SHA256:
return sha256.New()
case BLAKE2b512:
b2, _ := blake2b.New512(nil) // New512 never returns an error if the key is nil
return b2
case HighwayHash256:
hh, _ := highwayhash.New(magicHighwayHash256Key) // New will never return error since key is 256 bit
return hh
case HighwayHash256S:
hh, _ := highwayhash.New(magicHighwayHash256Key) // New will never return error since key is 256 bit
return hh
default:
logger.CriticalIf(GlobalContext, errors.New("Unsupported bitrot algorithm"))
return nil
}
}
// Available reports whether the given algorithm is available.
func (a BitrotAlgorithm) Available() bool {
_, ok := bitrotAlgorithms[a]
return ok
}
// String returns the string identifier for a given bitrot algorithm.
// If the algorithm is not supported String panics.
func (a BitrotAlgorithm) String() string {
name, ok := bitrotAlgorithms[a]
if !ok {
logger.CriticalIf(GlobalContext, errors.New("Unsupported bitrot algorithm"))
}
return name
}
// NewBitrotVerifier returns a new BitrotVerifier implementing the given algorithm.
func NewBitrotVerifier(algorithm BitrotAlgorithm, checksum []byte) *BitrotVerifier {
return &BitrotVerifier{algorithm, checksum}
}
// BitrotVerifier can be used to verify protected data.
type BitrotVerifier struct {
algorithm BitrotAlgorithm
sum []byte
}
// BitrotAlgorithmFromString returns a bitrot algorithm from the given string representation.
// It returns 0 if the string representation does not match any supported algorithm.
// The zero value of a bitrot algorithm is never supported.
func BitrotAlgorithmFromString(s string) (a BitrotAlgorithm) {
for alg, name := range bitrotAlgorithms {
if name == s {
return alg
}
}
return
}
func newBitrotWriter(disk StorageAPI, volume, filePath string, length int64, algo BitrotAlgorithm, shardSize int64, heal bool) io.Writer {
if algo == HighwayHash256S {
return newStreamingBitrotWriter(disk, volume, filePath, length, algo, shardSize, heal)
}
return newWholeBitrotWriter(disk, volume, filePath, algo, shardSize)
}
func newBitrotReader(disk StorageAPI, data []byte, bucket string, filePath string, tillOffset int64, algo BitrotAlgorithm, sum []byte, shardSize int64) io.ReaderAt {
if algo == HighwayHash256S {
return newStreamingBitrotReader(disk, data, bucket, filePath, tillOffset, algo, shardSize)
}
return newWholeBitrotReader(disk, bucket, filePath, algo, tillOffset, sum)
}
// Close all the readers.
func closeBitrotReaders(rs []io.ReaderAt) {
for _, r := range rs {
if br, ok := r.(io.Closer); ok {
br.Close()
}
}
}
// Close all the writers.
func closeBitrotWriters(ws []io.Writer) {
for _, w := range ws {
if bw, ok := w.(io.Closer); ok {
bw.Close()
}
}
}
// Returns hash sum for whole-bitrot, nil for streaming-bitrot.
func bitrotWriterSum(w io.Writer) []byte {
if bw, ok := w.(*wholeBitrotWriter); ok {
return bw.Sum(nil)
}
return nil
}
// Returns the size of the file with bitrot protection
func bitrotShardFileSize(size int64, shardSize int64, algo BitrotAlgorithm) int64 {
if algo != HighwayHash256S {
return size
}
return ceilFrac(size, shardSize)*int64(algo.New().Size()) + size
}
// bitrotVerify a single stream of data.
func bitrotVerify(r io.Reader, wantSize, partSize int64, algo BitrotAlgorithm, want []byte, shardSize int64) error {
if algo != HighwayHash256S {
h := algo.New()
if n, err := io.Copy(h, r); err != nil || n != wantSize {
// Premature failure in reading the object, file is corrupt.
return errFileCorrupt
}
if !bytes.Equal(h.Sum(nil), want) {
return errFileCorrupt
}
return nil
}
h := algo.New()
hashBuf := make([]byte, h.Size())
buf := make([]byte, shardSize)
left := wantSize
// Calculate the size of the bitrot file and compare
// it with the actual file size.
if left != bitrotShardFileSize(partSize, shardSize, algo) {
return errFileCorrupt
}
for left > 0 {
// Read expected hash...
h.Reset()
n, err := io.ReadFull(r, hashBuf)
if err != nil {
// Read's failed for object with right size, file is corrupt.
return err
}
// Subtract hash length..
left -= int64(n)
if left < shardSize {
shardSize = left
}
read, err := io.CopyBuffer(h, io.LimitReader(r, shardSize), buf)
if err != nil {
// Read's failed for object with right size, at different offsets.
return err
}
left -= read
if !bytes.Equal(h.Sum(nil), hashBuf) {
return errFileCorrupt
}
}
return nil
}
// bitrotSelfTest performs a self-test to ensure that bitrot
// algorithms compute correct checksums. If any algorithm
// produces an incorrect checksum it fails with a hard error.
//
// bitrotSelfTest tries to catch any issue in the bitrot implementation
// early instead of silently corrupting data.
func bitrotSelfTest() {
var checksums = map[BitrotAlgorithm]string{
SHA256: "a7677ff19e0182e4d52e3a3db727804abc82a5818749336369552e54b838b004",
BLAKE2b512: "e519b7d84b1c3c917985f544773a35cf265dcab10948be3550320d156bab612124a5ae2ae5a8c73c0eea360f68b0e28136f26e858756dbfe7375a7389f26c669",
HighwayHash256: "39c0407ed3f01b18d22c85db4aeff11e060ca5f43131b0126731ca197cd42313",
HighwayHash256S: "39c0407ed3f01b18d22c85db4aeff11e060ca5f43131b0126731ca197cd42313",
}
for algorithm := range bitrotAlgorithms {
if !algorithm.Available() {
continue
}
checksum, err := hex.DecodeString(checksums[algorithm])
if err != nil {
logger.Fatal(errSelfTestFailure, fmt.Sprintf("bitrot: failed to decode %v checksum %s for selftest: %v", algorithm, checksums[algorithm], err))
}
var (
hash = algorithm.New()
msg = make([]byte, 0, hash.Size()*hash.BlockSize())
sum = make([]byte, 0, hash.Size())
)
for i := 0; i < hash.Size()*hash.BlockSize(); i += hash.Size() {
hash.Write(msg)
sum = hash.Sum(sum[:0])
msg = append(msg, sum...)
hash.Reset()
}
if !bytes.Equal(sum, checksum) {
logger.Fatal(errSelfTestFailure, fmt.Sprintf("bitrot: %v selftest checksum mismatch: got %x - want %x", algorithm, sum, checksum))
}
}
}