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Copy pathbitrot.go
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187 lines (167 loc) · 5.69 KB
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/*
* 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 (
"context"
"errors"
"hash"
"io"
"github.com/minio/highwayhash"
"github.com/minio/minio/cmd/logger"
sha256 "github.com/minio/sha256-simd"
"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")
// BitrotAlgorithm specifies a algorithm used for bitrot protection.
type BitrotAlgorithm uint
const (
// SHA256 represents the SHA-256 hash function
SHA256 BitrotAlgorithm = 1 + iota
// HighwayHash256 represents the HighwayHash-256 hash function
HighwayHash256
// HighwayHash256S represents the Streaming HighwayHash-256 hash function
HighwayHash256S
// BLAKE2b512 represents the BLAKE2b-512 hash function
BLAKE2b512
)
// DefaultBitrotAlgorithm is the default algorithm used for bitrot protection.
const (
DefaultBitrotAlgorithm = HighwayHash256S
)
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(context.Background(), 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(context.Background(), 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) io.Writer {
if algo == HighwayHash256S {
return newStreamingBitrotWriter(disk, volume, filePath, length, algo, shardSize)
}
return newWholeBitrotWriter(disk, volume, filePath, length, algo, shardSize)
}
func newBitrotReader(disk StorageAPI, bucket string, filePath string, tillOffset int64, algo BitrotAlgorithm, sum []byte, shardSize int64) io.ReaderAt {
if algo == HighwayHash256S {
return newStreamingBitrotReader(disk, 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.(*streamingBitrotReader); ok {
br.Close()
}
}
}
// Close all the writers.
func closeBitrotWriters(ws []io.Writer) {
for _, w := range ws {
if bw, ok := w.(*streamingBitrotWriter); 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
}
// Verify if a file has bitrot error.
func bitrotCheckFile(disk StorageAPI, volume string, filePath string, tillOffset int64, algo BitrotAlgorithm, sum []byte, shardSize int64) (err error) {
if algo != HighwayHash256S {
buf := []byte{}
// For whole-file bitrot we don't need to read the entire file as the bitrot verify happens on the server side even if we read 0-bytes.
_, err = disk.ReadFile(volume, filePath, 0, buf, NewBitrotVerifier(algo, sum))
return err
}
buf := make([]byte, shardSize)
r := newStreamingBitrotReader(disk, volume, filePath, tillOffset, algo, shardSize)
defer closeBitrotReaders([]io.ReaderAt{r})
var offset int64
for {
if offset == tillOffset {
break
}
var n int
tmpBuf := buf
if int64(len(tmpBuf)) > (tillOffset - offset) {
tmpBuf = tmpBuf[:(tillOffset - offset)]
}
n, err = r.ReadAt(tmpBuf, offset)
if err != nil {
return err
}
offset += int64(n)
}
return nil
}