sftpgo-mirror/internal/mfa/totp.go
Nicola Murino 784b7585c1
remove end year from Copyright notice in files
so we don't have to update all the files every year

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>
2024-01-01 11:31:45 +01:00

120 lines
3.2 KiB
Go

// Copyright (C) 2019 Nicola Murino
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, version 3.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package mfa
import (
"bytes"
"errors"
"fmt"
"image/png"
"sync"
"time"
"github.com/pquerna/otp"
"github.com/pquerna/otp/totp"
)
// TOTPHMacAlgo is the enumerable for the possible HMAC algorithms for Time-based one time passwords
type TOTPHMacAlgo = string
// supported TOTP HMAC algorithms
const (
TOTPAlgoSHA1 TOTPHMacAlgo = "sha1"
TOTPAlgoSHA256 TOTPHMacAlgo = "sha256"
TOTPAlgoSHA512 TOTPHMacAlgo = "sha512"
)
var (
cleanupTicker *time.Ticker
cleanupDone chan bool
usedPasscodes sync.Map
errPasscodeUsed = errors.New("this passcode was already used")
)
// TOTPConfig defines the configuration for a Time-based one time password
type TOTPConfig struct {
Name string `json:"name" mapstructure:"name"`
Issuer string `json:"issuer" mapstructure:"issuer"`
Algo TOTPHMacAlgo `json:"algo" mapstructure:"algo"`
algo otp.Algorithm
}
func (c *TOTPConfig) validate() error {
if c.Name == "" {
return errors.New("totp: name is mandatory")
}
if c.Issuer == "" {
return errors.New("totp: issuer is mandatory")
}
switch c.Algo {
case TOTPAlgoSHA1:
c.algo = otp.AlgorithmSHA1
case TOTPAlgoSHA256:
c.algo = otp.AlgorithmSHA256
case TOTPAlgoSHA512:
c.algo = otp.AlgorithmSHA512
default:
return fmt.Errorf("unsupported totp algo %q", c.Algo)
}
return nil
}
// validatePasscode validates a TOTP passcode
func (c *TOTPConfig) validatePasscode(passcode, secret string) (bool, error) {
key := fmt.Sprintf("%v_%v", secret, passcode)
if _, ok := usedPasscodes.Load(key); ok {
return false, errPasscodeUsed
}
match, err := totp.ValidateCustom(passcode, secret, time.Now().UTC(), totp.ValidateOpts{
Period: 30,
Skew: 1,
Digits: otp.DigitsSix,
Algorithm: c.algo,
})
if match && err == nil {
usedPasscodes.Store(key, time.Now().Add(1*time.Minute).UTC())
}
return match, err
}
// generate generates a new TOTP secret and QR code for the given username
func (c *TOTPConfig) generate(username string, qrCodeWidth, qrCodeHeight int) (*otp.Key, []byte, error) {
key, err := totp.Generate(totp.GenerateOpts{
Issuer: c.Issuer,
AccountName: username,
Digits: otp.DigitsSix,
Algorithm: c.algo,
})
if err != nil {
return nil, nil, err
}
var buf bytes.Buffer
img, err := key.Image(qrCodeWidth, qrCodeHeight)
if err != nil {
return nil, nil, err
}
err = png.Encode(&buf, img)
return key, buf.Bytes(), err
}
func cleanupUsedPasscodes() {
usedPasscodes.Range(func(key, value any) bool {
exp, ok := value.(time.Time)
if !ok || exp.Before(time.Now().UTC()) {
usedPasscodes.Delete(key)
}
return true
})
}