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Do not use crypto.SHA3_256 as placeholder for HighwayHash256 (#5847)

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Krishna Srinivas 2018-05-04 10:42:22 -07:00 committed by Dee Koder
parent d69ba7d085
commit 0f746a14a3
1 changed files with 21 additions and 34 deletions
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55
cmd/xl-v1-metadata.go
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@ -18,7 +18,6 @@ package cmd
import (
"context"
"crypto"
"encoding/hex"
"encoding/json"
"errors"
@ -37,44 +36,24 @@ import (
const erasureAlgorithmKlauspost = "klauspost/reedsolomon/vandermonde"
// DefaultBitrotAlgorithm is the default algorithm used for bitrot protection.
var DefaultBitrotAlgorithm = HighwayHash256
func init() {
hh256Key, err := hex.DecodeString(magicHighwayHash256Key)
if err != nil || len(hh256Key) != highwayhash.Size {
logger.CriticalIf(context.Background(), errors.New("Failed to decode fixed magic HighwayHash256 key. Please report this bug at https://github.com/minio/minio/issues"))
}
newBLAKE2b := func() hash.Hash {
b2, _ := blake2b.New512(nil) // New512 never returns an error if the key is nil
return b2
}
newHighwayHash256 := func() hash.Hash {
hh, _ := highwayhash.New(hh256Key) // New will never return error since key is 256 bit
return hh
}
crypto.RegisterHash(crypto.Hash(SHA256), sha256.New)
crypto.RegisterHash(crypto.Hash(BLAKE2b512), newBLAKE2b)
crypto.RegisterHash(crypto.Hash(HighwayHash256), newHighwayHash256)
}
// 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 crypto.Hash
type BitrotAlgorithm uint
const (
// SHA256 represents the SHA-256 hash function
SHA256 = BitrotAlgorithm(crypto.SHA256)
SHA256 BitrotAlgorithm = 1 + iota
// HighwayHash256 represents the HighwayHash-256 hash function
HighwayHash256 = BitrotAlgorithm(crypto.SHA3_256) // we must define that HighwayHash-256 is SHA3-256 because there is no HighwayHash constant in golang/crypto yet.
magicHighwayHash256Key = "4be734fa8e238acd263e83e6bb968552040f935da39f441497e09d1322de36a0" // magic HH-256 key as HH-256 hash of the first 100 decimals of π as utf-8 string with a zero key.
HighwayHash256
// BLAKE2b512 represents the BLAKE2b-256 hash function
BLAKE2b512 = BitrotAlgorithm(crypto.BLAKE2b_512)
BLAKE2b512
)
// DefaultBitrotAlgorithm is the default algorithm used for bitrot protection.
var DefaultBitrotAlgorithm = HighwayHash256
var bitrotAlgorithms = map[BitrotAlgorithm]string{
SHA256: "sha256",
BLAKE2b512: "blake2b",
@ -85,16 +64,24 @@ var bitrotAlgorithms = map[BitrotAlgorithm]string{
// New logs error and exits if the algorithm is not supported or not
// linked into the binary.
func (a BitrotAlgorithm) New() hash.Hash {
if _, ok := bitrotAlgorithms[a]; !ok {
logger.CriticalIf(context.Background(), errors.New("Unsupported bitrot algorithm"))
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
}
return crypto.Hash(a).New()
logger.CriticalIf(context.Background(), errors.New("Unsupported bitrot algorithm"))
return nil
}
// Available reports whether the given algorihm is a supported and linked into the binary.
func (a BitrotAlgorithm) Available() bool {
_, ok := bitrotAlgorithms[a]
return ok && crypto.Hash(a).Available()
return ok
}
// String returns the string identifier for a given bitrot algorithm.