From edce41ae652b278aa938dd8b2208722f3ee6afb4 Mon Sep 17 00:00:00 2001
From: Morgan Bazalgette <git@howl.moe>
Date: Sun, 31 Dec 2017 03:19:42 +0100
Subject: [PATCH] go back to using CFB for AES decryption/encryption for 2FA
(#3274)
---
models/twofactor.go | 47 ++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 44 insertions(+), 3 deletions(-)
diff --git a/models/twofactor.go b/models/twofactor.go
index 36ff5db422..526ab917e8 100644
--- a/models/twofactor.go
+++ b/models/twofactor.go
@@ -5,11 +5,15 @@
package models
import (
+ "crypto/aes"
+ "crypto/cipher"
"crypto/md5"
+ "crypto/rand"
"crypto/subtle"
"encoding/base64"
+ "errors"
+ "io"
- "github.com/Unknwon/com"
"github.com/pquerna/otp/totp"
"code.gitea.io/gitea/modules/base"
@@ -52,7 +56,7 @@ func (t *TwoFactor) getEncryptionKey() []byte {
// SetSecret sets the 2FA secret.
func (t *TwoFactor) SetSecret(secret string) error {
- secretBytes, err := com.AESGCMEncrypt(t.getEncryptionKey(), []byte(secret))
+ secretBytes, err := aesEncrypt(t.getEncryptionKey(), []byte(secret))
if err != nil {
return err
}
@@ -66,7 +70,7 @@ func (t *TwoFactor) ValidateTOTP(passcode string) (bool, error) {
if err != nil {
return false, err
}
- secret, err := com.AESGCMDecrypt(t.getEncryptionKey(), decodedStoredSecret)
+ secret, err := aesDecrypt(t.getEncryptionKey(), decodedStoredSecret)
if err != nil {
return false, err
}
@@ -74,6 +78,43 @@ func (t *TwoFactor) ValidateTOTP(passcode string) (bool, error) {
return totp.Validate(passcode, secretStr), nil
}
+// aesEncrypt encrypts text and given key with AES.
+func aesEncrypt(key, text []byte) ([]byte, error) {
+ block, err := aes.NewCipher(key)
+ if err != nil {
+ return nil, err
+ }
+ b := base64.StdEncoding.EncodeToString(text)
+ ciphertext := make([]byte, aes.BlockSize+len(b))
+ iv := ciphertext[:aes.BlockSize]
+ if _, err := io.ReadFull(rand.Reader, iv); err != nil {
+ return nil, err
+ }
+ cfb := cipher.NewCFBEncrypter(block, iv)
+ cfb.XORKeyStream(ciphertext[aes.BlockSize:], []byte(b))
+ return ciphertext, nil
+}
+
+// aesDecrypt decrypts text and given key with AES.
+func aesDecrypt(key, text []byte) ([]byte, error) {
+ block, err := aes.NewCipher(key)
+ if err != nil {
+ return nil, err
+ }
+ if len(text) < aes.BlockSize {
+ return nil, errors.New("ciphertext too short")
+ }
+ iv := text[:aes.BlockSize]
+ text = text[aes.BlockSize:]
+ cfb := cipher.NewCFBDecrypter(block, iv)
+ cfb.XORKeyStream(text, text)
+ data, err := base64.StdEncoding.DecodeString(string(text))
+ if err != nil {
+ return nil, err
+ }
+ return data, nil
+}
+
// NewTwoFactor creates a new two-factor authentication token.
func NewTwoFactor(t *TwoFactor) error {
err := t.GenerateScratchToken()