Function ParseFirebaseScryptHash

internal/crypto/password.go:87–158

See: https://github.com/firebase/scrypt for implementation

(hash string)

// See: https://github.com/firebase/scrypt for implementation
func ParseFirebaseScryptHash(hash string) (*FirebaseScryptHashInput, error) {
	submatch := fbscryptHashRegexp.FindStringSubmatchIndex(hash)
	if submatch == nil {
		return nil, errors.New("crypto: incorrect scrypt hash format")
	}

	v := string(fbscryptHashRegexp.ExpandString(nil, "$v", hash, submatch))
	n := string(fbscryptHashRegexp.ExpandString(nil, "$n", hash, submatch))
	r := string(fbscryptHashRegexp.ExpandString(nil, "$r", hash, submatch))
	p := string(fbscryptHashRegexp.ExpandString(nil, "$p", hash, submatch))
	ss := string(fbscryptHashRegexp.ExpandString(nil, "$ss", hash, submatch))
	sk := string(fbscryptHashRegexp.ExpandString(nil, "$sk", hash, submatch))
	saltB64 := string(fbscryptHashRegexp.ExpandString(nil, "$salt", hash, submatch))
	hashB64 := string(fbscryptHashRegexp.ExpandString(nil, "$hash", hash, submatch))

	if v != "1" {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash uses unsupported version %q only version 1 is supported", v)
	}
	memoryPower, err := strconv.ParseUint(n, 10, 32)
	if err != nil {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash has invalid n parameter %q %w", n, err)
	}
	if memoryPower == 0 {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash has invalid n=0")
	}
	rounds, err := strconv.ParseUint(r, 10, 64)
	if err != nil {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash has invalid r parameter %q: %w", r, err)
	}
	if rounds == 0 {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash has invalid r=0")
	}

	threads, err := strconv.ParseUint(p, 10, 8)
	if err != nil {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash has invalid p parameter %q %w", p, err)
	}
	if threads == 0 {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash has invalid p=0")
	}

	rawHash, err := base64.StdEncoding.DecodeString(hashB64)
	if err != nil {
		return nil, fmt.Errorf("crypto: Firebase scrypt hash has invalid base64 in the hash section %w", err)
	}

	salt, err := base64.StdEncoding.DecodeString(saltB64)
	if err != nil {
		return nil, fmt.Errorf("crypto: Firebase scrypt salt has invalid base64 in the hash section %w", err)
	}

	var saltSeparator, signerKey []byte
	if signerKey, err = base64.StdEncoding.DecodeString(sk); err != nil {
		return nil, err
	}
	if saltSeparator, err = base64.StdEncoding.DecodeString(ss); err != nil {
		return nil, err
	}