Function parseRSA

internal/sshutil/sshutil.go:160–181

parseRSA parses an RSA key according to RFC 4253, section 6.6.

(in []byte)

// parseRSA parses an RSA key according to RFC 4253, section 6.6.
func parseRSA(in []byte) (*rsa.PublicKey, error) {
	var w struct {
		E    *big.Int
		N    *big.Int
		Rest []byte `ssh:"rest"`
	}
	if err := ssh.Unmarshal(in, &w); err != nil {
		return nil, errors.Wrap(err, "error unmarshaling public key")
	}
	if w.E.BitLen() > 24 {
		return nil, errors.New("invalid public key: exponent too large")
	}
	e := w.E.Int64()
	if e < 3 || e&1 == 0 {
		return nil, errors.New("invalid public key: incorrect exponent")
	}

	var key rsa.PublicKey
	key.E = int(e)
	key.N = w.N
	return &key, nil
}

// parseECDSA parses an ECDSA key according to RFC 5656, section 3.1.
//