Respect the period and number of digits

main.go

@@ -60,6 +60,8 @@ type entry struct {
 	Issuer    string `json:"issuer"`
 	Secret    string `json:"secret"`
 	Enc       string `json:"enc"`
+	Period    int    `json:"period"`
+	DigitsNo  int    `json:"digits"`
 }
 
 func deriveKeyFromPassword(p string, s []byte) ([]byte, []byte) {
@@ -79,18 +81,18 @@ func deriveKeyFromPassword(p string, s []byte) ([]byte, []byte) {
 	return m[:32], m[32:48]
 }
 
-func decryptAESCBC(p string, enc string) (rv []byte, err error) {
+func decryptAESCBC(p string, enc string) ([]byte, error) {
 	var tmp []byte
 	var c cipher.Block
 	var m cipher.BlockMode
+	var err error
 
 	if tmp, err = base64.StdEncoding.DecodeString(enc); err != nil {
-		return
+		return []byte{}, err
 	}
 
 	if !bytes.Equal(tmp[:8], []byte{0x53, 0x61, 0x6c, 0x74, 0x65, 0x64, 0x5f, 0x5f}) {
-		err = errors.New("Magic not found")
+		return []byte{}, errors.New("Magic not found")
-		return
 	}
 
 	key, iv := deriveKeyFromPassword(p, tmp[8:16])
@@ -98,7 +100,7 @@ func decryptAESCBC(p string, enc string) (rv []byte, err error) {
 	tmp = tmp[16:]
 
 	if c, err = aes.NewCipher(key); err != nil {
-		return
+		return []byte{}, err
 	}
 
 	m = cipher.NewCBCDecrypter(c, iv)
@@ -108,80 +110,7 @@ func decryptAESCBC(p string, enc string) (rv []byte, err error) {
 	if lastval <= 16 {
 		tmp = tmp[:len(tmp)-lastval]
 	}
-	rv = tmp
+	return tmp, nil
-	return
-}
-
-func getEntriesFromFile(n string, p string) ([]entry, error) {
-	var data string
-	var db *sql.DB
-	var err error
-	var entries map[string]entry
-	var pwddb string
-	var s []byte
-	var i int
-
-	if db, err = sql.Open("sqlite3", n); err != nil {
-		return nil, err
-	}
-	err = db.QueryRow("select data from storage_sync_data where ext_id=\"authenticator@mymindstorm\";").Scan(&data)
-	db.Close()
-	if err != nil {
-		return nil, err
-	}
-
-	if data == "" {
-		return nil, errors.New("no data found in database")
-	}
-
-	if err = json.Unmarshal([]byte(data), &entries); err != nil {
-		return nil, err
-	}
-
-	if pwd, ok := entries["key"]; ok {
-		keyPwd, err := decryptAESCBC(p, pwd.Enc)
-		if err != nil {
-			return nil, err
-		}
-		pwddb = fmt.Sprintf("%x", keyPwd)
-		delete(entries, "key")
-	}
-
-	rv := make([]entry, len(entries))
-	for _, v := range entries {
-		if v.Encrypted && pwddb != "" {
-			if s, err = decryptAESCBC(pwddb, v.Secret); err == nil {
-				v.Secret = string(s)
-				v.Encrypted = false
-			}
-		}
-		rv[i] = v
-		i++
-	}
-	return rv, err
-}
-
-func computeOTP(secret string) (uint32, error) {
-	var secretBytes []byte
-	var err error
-
-	secret = strings.ToUpper(strings.TrimSpace(secret))
-	if n := len(secret) % 8; n != 0 {
-		secret = secret + strings.Repeat("=", 8-n)
-	}
-
-	if secretBytes, err = base32.StdEncoding.DecodeString(secret); err != nil {
-		return 0, errors.New("decoding of secret as base32 failed")
-	}
-
-	mac := hmac.New(sha1.New, secretBytes)
-
-	binary.Write(mac, binary.BigEndian, uint64(math.Floor(float64(time.Now().Unix())/float64(30))))
-	sum := mac.Sum(nil)
-
-	offset := sum[len(sum)-1] & 0xf
-	value := binary.BigEndian.Uint32(sum[offset:offset+4]) & 0x7fffffff
-	return value % 1000000, nil
 }
 
 func getFirefoxSyncv2Path() (string, error) {
@@ -200,7 +129,103 @@ func getFirefoxSyncv2Path() (string, error) {
 	return u.HomeDir + "/.mozilla/firefox/" + p + "/storage-sync-v2.sqlite", nil
 }
 
-func getConfigurationFile() (entries []entry, err error) {
+func getEntriesFromFirefoxAuthenticator(fname string, password string) ([]*entry, error) {
+	var data string
+	var db *sql.DB
+	var err error
+	var entries map[string]*entry
+	var pwddb string
+	var s []byte
+	var i int
+
+	if fname == "" {
+		fname, err = getFirefoxSyncv2Path()
+		if err != nil {
+			return nil, err
+		}
+	}
+	if db, err = sql.Open("sqlite3", fname); err != nil {
+		return nil, err
+	}
+	err = db.QueryRow("select data from storage_sync_data where ext_id=\"authenticator@mymindstorm\";").Scan(&data)
+	db.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	if data == "" {
+		return nil, errors.New("no data found in database")
+	}
+	if err = json.Unmarshal([]byte(data), &entries); err != nil {
+		return nil, err
+	}
+
+	if pwd, ok := entries["key"]; ok {
+		if password != "" {
+			keyPwd, err := decryptAESCBC(password, pwd.Enc)
+			if err != nil {
+				return nil, err
+			}
+			pwddb = fmt.Sprintf("%x", keyPwd)
+		}
+		delete(entries, "key")
+	}
+
+	rv := make([]*entry, len(entries))
+	for _, v := range entries {
+		if v.Encrypted && pwddb != "" {
+			if s, err = decryptAESCBC(pwddb, v.Secret); err == nil {
+				v.Secret = string(s)
+				v.Encrypted = false
+			}
+		}
+		rv[i] = v
+		i++
+	}
+	return rv, err
+}
+
+func (e *entry) ComputeOTP() (string, error) {
+	var secretBytes []byte
+	var err error
+	var secret string
+	var period int
+	var digits int
+	const (
+		DefaultPeriod   = 30
+		DefaultDigitsNo = 6
+	)
+
+	secret = strings.ToUpper(strings.TrimSpace(e.Secret))
+	if n := len(secret) % 8; n != 0 {
+		secret = secret + strings.Repeat("=", 8-n)
+	}
+
+	if secretBytes, err = base32.StdEncoding.DecodeString(secret); err != nil {
+		return "", errors.New("decoding of secret as base32 failed")
+	}
+
+	period = e.Period
+	if period == 0 {
+		period = DefaultPeriod
+	}
+	digits = e.DigitsNo
+	if digits == 0 {
+		digits = DefaultDigitsNo
+	}
+
+	mac := hmac.New(sha1.New, secretBytes)
+
+	binary.Write(mac, binary.BigEndian,
+		uint64(math.Floor(float64(time.Now().Unix())/float64(period))))
+	sum := mac.Sum(nil)
+
+	offset := sum[len(sum)-1] & 0xf
+	value := binary.BigEndian.Uint32(sum[offset:offset+4]) & 0x7fffffff
+	return fmt.Sprintf("%0*d", digits, uint64(value)%uint64(math.Pow10(digits))), nil
+}
+
+func getEntriesFromConfigFile() (entries []*entry, err error) {
 	var u *user.User
 	var data []byte
 	var fname string
@@ -226,7 +251,7 @@ func main() {
 	var dbf string
 	var passwd string
 	var err error
-	var entries []entry
+	var entries []*entry
 	var firefox bool
 
 	flag.StringVar(&dbf, "d", "", "Database file")
@@ -236,19 +261,12 @@ func main() {
 	flag.Parse()
 
 	if firefox || dbf != "" {
-		if dbf == "" {
+		if entries, err = getEntriesFromFirefoxAuthenticator(dbf, passwd); err != nil {
-			dbf, err = getFirefoxSyncv2Path()
-			if err != nil {
-				fmt.Printf("%s\n", err)
-				return
-			}
-		}
-		if entries, err = getEntriesFromFile(dbf, passwd); err != nil {
 			fmt.Printf("%s\n", err)
 			return
 		}
 	} else {
-		if entries, err = getConfigurationFile(); err != nil {
+		if entries, err = getEntriesFromConfigFile(); err != nil {
 			fmt.Printf("%s\n", err)
 			return
 		}
@@ -258,19 +276,20 @@ func main() {
 		if v.Encrypted {
 			continue
 		}
+
 		if sentry == "" {
-			p, err := computeOTP(v.Secret)
+			p, err := v.ComputeOTP()
 			if err != nil {
 				fmt.Printf("%s: %s\n", v.Issuer, err)
 			} else {
-				fmt.Printf("%s: %06d\n", v.Issuer, p)
+				fmt.Printf("%s: %s\n", v.Issuer, p)
 			}
 		} else if v.Issuer == sentry {
-			p, err := computeOTP(v.Secret)
+			p, err := v.ComputeOTP()
 			if err != nil {
 				fmt.Printf("%s\n", err)
 			} else {
-				fmt.Printf("%06d\n", p)
+				fmt.Printf("%s\n", p)
 			}
 		}
 	}