mirror of
https://github.com/drakkan/sftpgo.git
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120 lines
3.2 KiB
Go
120 lines
3.2 KiB
Go
// Copyright (C) 2019-2023 Nicola Murino
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published
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// by the Free Software Foundation, version 3.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package mfa
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import (
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"bytes"
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"errors"
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"fmt"
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"image/png"
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"sync"
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"time"
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"github.com/pquerna/otp"
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"github.com/pquerna/otp/totp"
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)
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// TOTPHMacAlgo is the enumerable for the possible HMAC algorithms for Time-based one time passwords
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type TOTPHMacAlgo = string
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// supported TOTP HMAC algorithms
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const (
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TOTPAlgoSHA1 TOTPHMacAlgo = "sha1"
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TOTPAlgoSHA256 TOTPHMacAlgo = "sha256"
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TOTPAlgoSHA512 TOTPHMacAlgo = "sha512"
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)
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var (
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cleanupTicker *time.Ticker
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cleanupDone chan bool
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usedPasscodes sync.Map
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errPasscodeUsed = errors.New("this passcode was already used")
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)
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// TOTPConfig defines the configuration for a Time-based one time password
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type TOTPConfig struct {
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Name string `json:"name" mapstructure:"name"`
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Issuer string `json:"issuer" mapstructure:"issuer"`
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Algo TOTPHMacAlgo `json:"algo" mapstructure:"algo"`
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algo otp.Algorithm
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}
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func (c *TOTPConfig) validate() error {
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if c.Name == "" {
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return errors.New("totp: name is mandatory")
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}
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if c.Issuer == "" {
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return errors.New("totp: issuer is mandatory")
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}
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switch c.Algo {
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case TOTPAlgoSHA1:
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c.algo = otp.AlgorithmSHA1
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case TOTPAlgoSHA256:
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c.algo = otp.AlgorithmSHA256
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case TOTPAlgoSHA512:
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c.algo = otp.AlgorithmSHA512
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default:
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return fmt.Errorf("unsupported totp algo %q", c.Algo)
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}
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return nil
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}
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// validatePasscode validates a TOTP passcode
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func (c *TOTPConfig) validatePasscode(passcode, secret string) (bool, error) {
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key := fmt.Sprintf("%v_%v", secret, passcode)
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if _, ok := usedPasscodes.Load(key); ok {
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return false, errPasscodeUsed
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}
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match, err := totp.ValidateCustom(passcode, secret, time.Now().UTC(), totp.ValidateOpts{
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Period: 30,
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Skew: 1,
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Digits: otp.DigitsSix,
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Algorithm: c.algo,
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})
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if match && err == nil {
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usedPasscodes.Store(key, time.Now().Add(1*time.Minute).UTC())
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}
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return match, err
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}
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// generate generates a new TOTP secret and QR code for the given username
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func (c *TOTPConfig) generate(username string, qrCodeWidth, qrCodeHeight int) (*otp.Key, []byte, error) {
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key, err := totp.Generate(totp.GenerateOpts{
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Issuer: c.Issuer,
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AccountName: username,
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Digits: otp.DigitsSix,
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Algorithm: c.algo,
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})
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if err != nil {
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return nil, nil, err
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}
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var buf bytes.Buffer
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img, err := key.Image(qrCodeWidth, qrCodeHeight)
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if err != nil {
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return nil, nil, err
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}
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err = png.Encode(&buf, img)
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return key, buf.Bytes(), err
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}
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func cleanupUsedPasscodes() {
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usedPasscodes.Range(func(key, value any) bool {
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exp, ok := value.(time.Time)
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if !ok || exp.Before(time.Now().UTC()) {
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usedPasscodes.Delete(key)
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}
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return true
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})
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}
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