xs/vendor/gopkg.in/hlandau/passlib.v1/hash/scrypt/scrypt.go

113 lines
2.7 KiB
Go

// Package scrypt implements the scrypt password hashing mechanism, wrapped in
// the modular crypt format.
package scrypt
import "fmt"
import "expvar"
import "strings"
import "crypto/rand"
import "encoding/base64"
import "gopkg.in/hlandau/passlib.v1/hash/scrypt/raw"
import "gopkg.in/hlandau/passlib.v1/abstract"
var cScryptSHA256HashCalls = expvar.NewInt("passlib.scryptsha256.hashCalls")
var cScryptSHA256VerifyCalls = expvar.NewInt("passlib.scryptsha256.verifyCalls")
// An implementation of Scheme performing scrypt-sha256.
//
// Uses the recommended values for N,r,p defined in raw.
var SHA256Crypter abstract.Scheme
func init() {
SHA256Crypter = NewSHA256(
raw.RecommendedN,
raw.Recommendedr,
raw.Recommendedp,
)
}
// Returns an implementation of Scheme implementing scrypt-sha256
// with the specified parameters.
func NewSHA256(N, r, p int) abstract.Scheme {
return &scryptSHA256Crypter{
nN: N,
r: r,
p: p,
}
}
type scryptSHA256Crypter struct {
nN, r, p int
}
func (c *scryptSHA256Crypter) SetParams(N, r, p int) error {
c.nN = N
c.r = r
c.p = p
return nil
}
func (c *scryptSHA256Crypter) SupportsStub(stub string) bool {
return strings.HasPrefix(stub, "$s2$")
}
func (c *scryptSHA256Crypter) Hash(password string) (string, error) {
cScryptSHA256HashCalls.Add(1)
stub, err := c.makeStub()
if err != nil {
return "", err
}
_, newHash, _, _, _, _, err := c.hash(password, stub)
return newHash, err
}
func (c *scryptSHA256Crypter) Verify(password, hash string) (err error) {
cScryptSHA256VerifyCalls.Add(1)
_, newHash, _, _, _, _, err := c.hash(password, hash)
if err == nil && !abstract.SecureCompare(hash, newHash) {
err = abstract.ErrInvalidPassword
}
return
}
func (c *scryptSHA256Crypter) NeedsUpdate(stub string) bool {
salt, _, N, r, p, err := raw.Parse(stub)
if err != nil {
return false // ...
}
return c.needsUpdate(salt, N, r, p)
}
func (c *scryptSHA256Crypter) needsUpdate(salt []byte, N, r, p int) bool {
return len(salt) < 18 || N < c.nN || r < c.r || p < c.p
}
func (c *scryptSHA256Crypter) hash(password, stub string) (oldHashRaw []byte, newHash string, salt []byte, N, r, p int, err error) {
salt, oldHashRaw, N, r, p, err = raw.Parse(stub)
if err != nil {
return
}
return oldHashRaw, raw.ScryptSHA256(password, salt, N, r, p), salt, N, r, p, nil
}
func (c *scryptSHA256Crypter) makeStub() (string, error) {
buf := make([]byte, 18)
_, err := rand.Read(buf)
if err != nil {
return "", err
}
salt := base64.StdEncoding.EncodeToString(buf)
return fmt.Sprintf("$s2$%d$%d$%d$%s", c.nN, c.r, c.p, salt), nil
}
func (c *scryptSHA256Crypter) String() string {
return fmt.Sprintf("scrypt-sha256(%d,%d,%d)", c.nN, c.r, c.p)
}