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// Copyright 2017 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package auth
import (
"crypto/md5"
"crypto/sha256"
"crypto/subtle"
"encoding/base32"
"encoding/base64"
"fmt"
"code.gitea.io/gitea/models/db"
"code.gitea.io/gitea/modules/secret"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/timeutil"
"code.gitea.io/gitea/modules/util"
"github.com/pquerna/otp/totp"
"golang.org/x/crypto/pbkdf2"
)
//
// Two-factor authentication
//
// ErrTwoFactorNotEnrolled indicates that a user is not enrolled in two-factor authentication.
type ErrTwoFactorNotEnrolled struct {
UID int64
}
// IsErrTwoFactorNotEnrolled checks if an error is a ErrTwoFactorNotEnrolled.
func IsErrTwoFactorNotEnrolled(err error) bool {
_, ok := err.(ErrTwoFactorNotEnrolled)
return ok
}
func (err ErrTwoFactorNotEnrolled) Error() string {
return fmt.Sprintf("user not enrolled in 2FA [uid: %d]", err.UID)
}
// TwoFactor represents a two-factor authentication token.
type TwoFactor struct {
ID int64 `xorm:"pk autoincr"`
UID int64 `xorm:"UNIQUE"`
Secret string
ScratchSalt string
ScratchHash string
LastUsedPasscode string `xorm:"VARCHAR(10)"`
CreatedUnix timeutil.TimeStamp `xorm:"INDEX created"`
UpdatedUnix timeutil.TimeStamp `xorm:"INDEX updated"`
}
func init() {
db.RegisterModel(new(TwoFactor))
}
// GenerateScratchToken recreates the scratch token the user is using.
func (t *TwoFactor) GenerateScratchToken() (string, error) {
tokenBytes, err := util.CryptoRandomBytes(6)
if err != nil {
return "", err
}
// these chars are specially chosen, avoid ambiguous chars like `0`, `O`, `1`, `I`.
const base32Chars = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"
token := base32.NewEncoding(base32Chars).WithPadding(base32.NoPadding).EncodeToString(tokenBytes)
t.ScratchSalt, _ = util.CryptoRandomString(10)
t.ScratchHash = HashToken(token, t.ScratchSalt)
return token, nil
}
// HashToken return the hashable salt
func HashToken(token, salt string) string {
tempHash := pbkdf2.Key([]byte(token), []byte(salt), 10000, 50, sha256.New)
return fmt.Sprintf("%x", tempHash)
}
// VerifyScratchToken verifies if the specified scratch token is valid.
func (t *TwoFactor) VerifyScratchToken(token string) bool {
if len(token) == 0 {
return false
}
tempHash := HashToken(token, t.ScratchSalt)
return subtle.ConstantTimeCompare([]byte(t.ScratchHash), []byte(tempHash)) == 1
}
func (t *TwoFactor) getEncryptionKey() []byte {
k := md5.Sum([]byte(setting.SecretKey))
return k[:]
}
// SetSecret sets the 2FA secret.
func (t *TwoFactor) SetSecret(secretString string) error {
secretBytes, err := secret.AesEncrypt(t.getEncryptionKey(), []byte(secretString))
if err != nil {
return err
}
t.Secret = base64.StdEncoding.EncodeToString(secretBytes)
return nil
}
// ValidateTOTP validates the provided passcode.
func (t *TwoFactor) ValidateTOTP(passcode string) (bool, error) {
decodedStoredSecret, err := base64.StdEncoding.DecodeString(t.Secret)
if err != nil {
return false, err
}
secretBytes, err := secret.AesDecrypt(t.getEncryptionKey(), decodedStoredSecret)
if err != nil {
return false, err
}
secretStr := string(secretBytes)
return totp.Validate(passcode, secretStr), nil
}
// NewTwoFactor creates a new two-factor authentication token.
func NewTwoFactor(t *TwoFactor) error {
_, err := db.GetEngine(db.DefaultContext).Insert(t)
return err
}
// UpdateTwoFactor updates a two-factor authentication token.
func UpdateTwoFactor(t *TwoFactor) error {
_, err := db.GetEngine(db.DefaultContext).ID(t.ID).AllCols().Update(t)
return err
}
// GetTwoFactorByUID returns the two-factor authentication token associated with
// the user, if any.
func GetTwoFactorByUID(uid int64) (*TwoFactor, error) {
twofa := &TwoFactor{}
has, err := db.GetEngine(db.DefaultContext).Where("uid=?", uid).Get(twofa)
if err != nil {
return nil, err
} else if !has {
return nil, ErrTwoFactorNotEnrolled{uid}
}
return twofa, nil
}
// HasTwoFactorByUID returns the two-factor authentication token associated with
// the user, if any.
func HasTwoFactorByUID(uid int64) (bool, error) {
return db.GetEngine(db.DefaultContext).Where("uid=?", uid).Exist(&TwoFactor{})
}
// DeleteTwoFactorByID deletes two-factor authentication token by given ID.
func DeleteTwoFactorByID(id, userID int64) error {
cnt, err := db.GetEngine(db.DefaultContext).ID(id).Delete(&TwoFactor{
UID: userID,
})
if err != nil {
return err
} else if cnt != 1 {
return ErrTwoFactorNotEnrolled{userID}
}
return nil
}
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