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