1
0
mirror of https://github.com/golang/go synced 2024-11-25 06:57:58 -07:00

crypto/bcrypt: new package

A port of Provos and Mazières's adapative hashing algorithm. See http://www.usenix.org/events/usenix99/provos/provos_html/node1.html

R=bradfitz, agl, rsc, dchest
CC=golang-dev
https://golang.org/cl/4964078
This commit is contained in:
Jeff Hodges 2011-09-19 10:29:02 -04:00 committed by Adam Langley
parent 5d5d7f1229
commit d072a70823
5 changed files with 528 additions and 0 deletions

View File

@ -33,6 +33,7 @@ DIRS=\
crypto\
crypto/aes\
crypto/blowfish\
crypto/bcrypt\
crypto/cast5\
crypto/cipher\
crypto/des\

View File

@ -0,0 +1,12 @@
# Copyright 2011 The Go Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.
include ../../../Make.inc
TARG=crypto/bcrypt
GOFILES=\
base64.go \
bcrypt.go
include ../../../Make.pkg

View File

@ -0,0 +1,38 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bcrypt
import (
"encoding/base64"
"os"
)
const alphabet = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
var bcEncoding = base64.NewEncoding(alphabet)
func base64Encode(src []byte) []byte {
n := bcEncoding.EncodedLen(len(src))
dst := make([]byte, n)
bcEncoding.Encode(dst, src)
for dst[n-1] == '=' {
n--
}
return dst[:n]
}
func base64Decode(src []byte) ([]byte, os.Error) {
numOfEquals := 4 - (len(src) % 4)
for i := 0; i < numOfEquals; i++ {
src = append(src, '=')
}
dst := make([]byte, bcEncoding.DecodedLen(len(src)))
n, err := bcEncoding.Decode(dst, src)
if err != nil {
return nil, err
}
return dst[:n], nil
}

View File

@ -0,0 +1,282 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package bcrypt implements Provos and Mazières's bcrypt adapative hashing
// algorithm. See http://www.usenix.org/event/usenix99/provos/provos.pdf
package bcrypt
// The code is a port of Provos and Mazières's C implementation.
import (
"crypto/blowfish"
"crypto/rand"
"crypto/subtle"
"fmt"
"io"
"os"
"strconv"
)
const (
MinCost int = 4 // the minimum allowable cost as passed in to GenerateFromPassword
MaxCost int = 31 // the maximum allowable cost as passed in to GenerateFromPassword
DefaultCost int = 10 // the cost that will actually be set if a cost below MinCost is passed into GenerateFromPassword
)
// The error returned from CompareHashAndPassword when a password and hash do
// not match.
var MismatchedHashAndPasswordError = os.NewError("crypto/bcrypt: hashedPassword is not the hash of the given password")
// The error returned from CompareHashAndPassword when a hash is too short to
// be a bcrypt hash.
var HashTooShortError = os.NewError("crypto/bcrypt: hashedSecret too short to be a bcrypted password")
// The error returned from CompareHashAndPassword when a hash was created with
// a bcrypt algorithm newer than this implementation.
type HashVersionTooNewError byte
func (hv HashVersionTooNewError) String() string {
return fmt.Sprintf("crypto/bcrypt: bcrypt algorithm version '%c' requested is newer than current version '%c'", byte(hv), majorVersion)
}
// The error returned from CompareHashAndPassword when a hash starts with something other than '$'
type InvalidHashPrefixError byte
func (ih InvalidHashPrefixError) String() string {
return fmt.Sprintf("crypto/bcrypt: bcrypt hashes must start with '$', but hashedSecret started with '%c'", byte(ih))
}
type InvalidCostError int
func (ic InvalidCostError) String() string {
return fmt.Sprintf("crypto/bcrypt: cost %d is outside allowed range (%d,%d)", int(ic), int(MinCost), int(MaxCost))
}
const (
majorVersion = '2'
minorVersion = 'a'
maxSaltSize = 16
maxCryptedHashSize = 23
encodedSaltSize = 22
encodedHashSize = 31
minHashSize = 59
)
// magicCipherData is an IV for the 64 Blowfish encryption calls in
// bcrypt(). It's the string "OrpheanBeholderScryDoubt" in big-endian bytes.
var magicCipherData = []byte{
0x4f, 0x72, 0x70, 0x68,
0x65, 0x61, 0x6e, 0x42,
0x65, 0x68, 0x6f, 0x6c,
0x64, 0x65, 0x72, 0x53,
0x63, 0x72, 0x79, 0x44,
0x6f, 0x75, 0x62, 0x74,
}
type hashed struct {
hash []byte
salt []byte
cost uint32 // allowed range is MinCost to MaxCost
major byte
minor byte
}
// GenerateFromPassword returns the bcrypt hash of the password at the given
// cost. If the cost given is less than MinCost, the cost will be set to
// MinCost, instead. Use CompareHashAndPassword, as defined in this package,
// to compare the returned hashed password with its cleartext version.
func GenerateFromPassword(password []byte, cost int) ([]byte, os.Error) {
p, err := newFromPassword(password, cost)
if err != nil {
return nil, err
}
return p.Hash(), nil
}
// CompareHashAndPassword compares a bcrypt hashed password with its possible
// plaintext equivalent. Note: Using bytes.Equal for this job is
// insecure. Returns nil on success, or an error on failure.
func CompareHashAndPassword(hashedPassword, password []byte) os.Error {
p, err := newFromHash(hashedPassword)
if err != nil {
return err
}
otherHash, err := bcrypt(password, p.cost, p.salt)
if err != nil {
return err
}
otherP := &hashed{otherHash, p.salt, p.cost, p.major, p.minor}
if subtle.ConstantTimeCompare(p.Hash(), otherP.Hash()) == 1 {
return nil
}
return MismatchedHashAndPasswordError
}
func newFromPassword(password []byte, cost int) (*hashed, os.Error) {
if cost < MinCost {
cost = DefaultCost
}
p := new(hashed)
p.major = majorVersion
p.minor = minorVersion
err := checkCost(cost)
if err != nil {
return nil, err
}
p.cost = uint32(cost)
unencodedSalt := make([]byte, maxSaltSize)
_, err = io.ReadFull(rand.Reader, unencodedSalt)
if err != nil {
return nil, err
}
p.salt = base64Encode(unencodedSalt)
hash, err := bcrypt(password, p.cost, p.salt)
if err != nil {
return nil, err
}
p.hash = hash
return p, err
}
func newFromHash(hashedSecret []byte) (*hashed, os.Error) {
if len(hashedSecret) < minHashSize {
return nil, HashTooShortError
}
p := new(hashed)
n, err := p.decodeVersion(hashedSecret)
if err != nil {
return nil, err
}
hashedSecret = hashedSecret[n:]
n, err = p.decodeCost(hashedSecret)
if err != nil {
return nil, err
}
hashedSecret = hashedSecret[n:]
// The "+2" is here because we'll have to append at most 2 '=' to the salt
// when base64 decoding it in expensiveBlowfishSetup().
p.salt = make([]byte, encodedSaltSize, encodedSaltSize+2)
copy(p.salt, hashedSecret[:encodedSaltSize])
hashedSecret = hashedSecret[encodedSaltSize:]
p.hash = make([]byte, len(hashedSecret))
copy(p.hash, hashedSecret)
return p, nil
}
func bcrypt(password []byte, cost uint32, salt []byte) ([]byte, os.Error) {
cipherData := make([]byte, len(magicCipherData))
copy(cipherData, magicCipherData)
c, err := expensiveBlowfishSetup(password, cost, salt)
if err != nil {
return nil, err
}
for i := 0; i < 24; i += 8 {
for j := 0; j < 64; j++ {
c.Encrypt(cipherData[i:i+8], cipherData[i:i+8])
}
}
// Bug compatibility with C bcrypt implementations. We only encode 23 of
// the 24 bytes encrypted.
hsh := base64Encode(cipherData[:maxCryptedHashSize])
return hsh, nil
}
func expensiveBlowfishSetup(key []byte, cost uint32, salt []byte) (*blowfish.Cipher, os.Error) {
csalt, err := base64Decode(salt)
if err != nil {
return nil, err
}
// Bug compatibility with C bcrypt implementations. They use the trailing
// NULL in the key string during expansion.
ckey := append(key, 0)
c, err := blowfish.NewSaltedCipher(ckey, csalt)
if err != nil {
return nil, err
}
rounds := 1 << cost
for i := 0; i < rounds; i++ {
blowfish.ExpandKey(ckey, c)
blowfish.ExpandKey(csalt, c)
}
return c, nil
}
func (p *hashed) Hash() []byte {
arr := make([]byte, 60)
arr[0] = '$'
arr[1] = p.major
n := 2
if p.minor != 0 {
arr[2] = p.minor
n = 3
}
arr[n] = '$'
n += 1
copy(arr[n:], []byte(fmt.Sprintf("%02d", p.cost)))
n += 2
arr[n] = '$'
n += 1
copy(arr[n:], p.salt)
n += encodedSaltSize
copy(arr[n:], p.hash)
n += encodedHashSize
return arr[:n]
}
func (p *hashed) decodeVersion(sbytes []byte) (int, os.Error) {
if sbytes[0] != '$' {
return -1, InvalidHashPrefixError(sbytes[0])
}
if sbytes[1] > majorVersion {
return -1, HashVersionTooNewError(sbytes[1])
}
p.major = sbytes[1]
n := 3
if sbytes[2] != '$' {
p.minor = sbytes[2]
n++
}
return n, nil
}
// sbytes should begin where decodeVersion left off.
func (p *hashed) decodeCost(sbytes []byte) (int, os.Error) {
cost, err := strconv.Atoi(string(sbytes[0:2]))
if err != nil {
return -1, err
}
err = checkCost(cost)
if err != nil {
return -1, err
}
p.cost = uint32(cost)
return 3, nil
}
func (p *hashed) String() string {
return fmt.Sprintf("&{hash: %#v, salt: %#v, cost: %d, major: %c, minor: %c}", string(p.hash), p.salt, p.cost, p.major, p.minor)
}
func checkCost(cost int) os.Error {
if cost < MinCost || cost > MaxCost {
return InvalidCostError(cost)
}
return nil
}

View File

@ -0,0 +1,195 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bcrypt
import (
"bytes"
"os"
"testing"
)
func TestBcryptingIsEasy(t *testing.T) {
pass := []byte("mypassword")
hp, err := GenerateFromPassword(pass, 0)
if err != nil {
t.Fatalf("GenerateFromPassword error: %s", err)
}
if CompareHashAndPassword(hp, pass) != nil {
t.Errorf("%v should hash %s correctly", hp, pass)
}
notPass := "notthepass"
err = CompareHashAndPassword(hp, []byte(notPass))
if err != MismatchedHashAndPasswordError {
t.Errorf("%v and %s should be mismatched", hp, notPass)
}
}
func TestBcryptingIsCorrect(t *testing.T) {
pass := []byte("allmine")
salt := []byte("XajjQvNhvvRt5GSeFk1xFe")
expectedHash := []byte("$2a$10$XajjQvNhvvRt5GSeFk1xFeyqRrsxkhBkUiQeg0dt.wU1qD4aFDcga")
hash, err := bcrypt(pass, 10, salt)
if err != nil {
t.Fatalf("bcrypt blew up: %v", err)
}
if !bytes.HasSuffix(expectedHash, hash) {
t.Errorf("%v should be the suffix of %v", hash, expectedHash)
}
h, err := newFromHash(expectedHash)
if err != nil {
t.Errorf("Unable to parse %s: %v", string(expectedHash), err)
}
// This is not the safe way to compare these hashes. We do this only for
// testing clarity. Use bcrypt.CompareHashAndPassword()
if err == nil && !bytes.Equal(expectedHash, h.Hash()) {
t.Errorf("Parsed hash %v should equal %v", h.Hash(), expectedHash)
}
}
func TestTooLongPasswordsWork(t *testing.T) {
salt := []byte("XajjQvNhvvRt5GSeFk1xFe")
// One byte over the usual 56 byte limit that blowfish has
tooLongPass := []byte("012345678901234567890123456789012345678901234567890123456")
tooLongExpected := []byte("$2a$10$XajjQvNhvvRt5GSeFk1xFe5l47dONXg781AmZtd869sO8zfsHuw7C")
hash, err := bcrypt(tooLongPass, 10, salt)
if err != nil {
t.Fatalf("bcrypt blew up on long password: %v", err)
}
if !bytes.HasSuffix(tooLongExpected, hash) {
t.Errorf("%v should be the suffix of %v", hash, tooLongExpected)
}
}
type InvalidHashTest struct {
err os.Error
hash []byte
}
var invalidTests = []InvalidHashTest{
{HashTooShortError, []byte("$2a$10$fooo")},
{HashTooShortError, []byte("$2a")},
{HashVersionTooNewError('3'), []byte("$3a$10$sssssssssssssssssssssshhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh")},
{InvalidHashPrefixError('%'), []byte("%2a$10$sssssssssssssssssssssshhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh")},
{InvalidCostError(32), []byte("$2a$32$sssssssssssssssssssssshhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh")},
}
func TestInvalidHashErrors(t *testing.T) {
check := func(name string, expected, err os.Error) {
if err == nil {
t.Errorf("%s: Should have returned an error", name)
}
if err != nil && err != expected {
t.Errorf("%s gave err %v but should have given %v", name, err.String(), expected.String())
}
}
for _, iht := range invalidTests {
_, err := newFromHash(iht.hash)
check("newFromHash", iht.err, err)
err = CompareHashAndPassword(iht.hash, []byte("anything"))
check("CompareHashAndPassword", iht.err, err)
}
}
func TestUnpaddedBase64Encoding(t *testing.T) {
original := []byte{101, 201, 101, 75, 19, 227, 199, 20, 239, 236, 133, 32, 30, 109, 243, 30}
encodedOriginal := []byte("XajjQvNhvvRt5GSeFk1xFe")
encoded := base64Encode(original)
if !bytes.Equal(encodedOriginal, encoded) {
t.Errorf("Encoded %v should have equaled %v", encoded, encodedOriginal)
}
decoded, err := base64Decode(encodedOriginal)
if err != nil {
t.Fatalf("base64Decode blew up: %s", err)
}
if !bytes.Equal(decoded, original) {
t.Errorf("Decoded %v should have equaled %v", decoded, original)
}
}
func TestCost(t *testing.T) {
if testing.Short() {
return
}
pass := []byte("mypassword")
for c := 0; c < MinCost; c++ {
p, _ := newFromPassword(pass, c)
if p.cost != uint32(DefaultCost) {
t.Errorf("newFromPassword should default costs below %d to %d, but was %d", MinCost, DefaultCost, p.cost)
}
}
p, _ := newFromPassword(pass, 14)
if p.cost != 14 {
t.Errorf("newFromPassword should default cost to 14, but was %d", p.cost)
}
hp, _ := newFromHash(p.Hash())
if p.cost != hp.cost {
t.Errorf("newFromHash should maintain the cost at %d, but was %d", p.cost, hp.cost)
}
_, err := newFromPassword(pass, 32)
if err == nil {
t.Fatalf("newFromPassword: should return a cost error")
}
if err != InvalidCostError(32) {
t.Errorf("newFromPassword: should return cost error, got %#v", err)
}
}
func TestCostReturnsWithLeadingZeroes(t *testing.T) {
hp, _ := newFromPassword([]byte("abcdefgh"), 7)
cost := hp.Hash()[4:7]
expected := []byte("07$")
if !bytes.Equal(expected, cost) {
t.Errorf("single digit costs in hash should have leading zeros: was %v instead of %v", cost, expected)
}
}
func TestMinorNotRequired(t *testing.T) {
noMinorHash := []byte("$2$10$XajjQvNhvvRt5GSeFk1xFeyqRrsxkhBkUiQeg0dt.wU1qD4aFDcga")
h, err := newFromHash(noMinorHash)
if err != nil {
t.Fatalf("No minor hash blew up: %s", err)
}
if h.minor != 0 {
t.Errorf("Should leave minor version at 0, but was %d", h.minor)
}
if !bytes.Equal(noMinorHash, h.Hash()) {
t.Errorf("Should generate hash %v, but created %v", noMinorHash, h.Hash())
}
}
func BenchmarkEqual(b *testing.B) {
b.StopTimer()
passwd := []byte("somepasswordyoulike")
hash, _ := GenerateFromPassword(passwd, 10)
b.StartTimer()
for i := 0; i < b.N; i++ {
CompareHashAndPassword(hash, passwd)
}
}
func BenchmarkGeneration(b *testing.B) {
b.StopTimer()
passwd := []byte("mylongpassword1234")
b.StartTimer()
for i := 0; i < b.N; i++ {
GenerateFromPassword(passwd, 10)
}
}