dex/vendor/gopkg.in/square/go-jose.v1/jwk.go
2016-07-26 15:51:24 -07:00

408 lines
9.8 KiB
Go

/*-
* Copyright 2014 Square Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jose
import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rsa"
"fmt"
"math/big"
"reflect"
"strings"
)
// rawJsonWebKey represents a public or private key in JWK format, used for parsing/serializing.
type rawJsonWebKey struct {
Use string `json:"use,omitempty"`
Kty string `json:"kty,omitempty"`
Kid string `json:"kid,omitempty"`
Crv string `json:"crv,omitempty"`
Alg string `json:"alg,omitempty"`
K *byteBuffer `json:"k,omitempty"`
X *byteBuffer `json:"x,omitempty"`
Y *byteBuffer `json:"y,omitempty"`
N *byteBuffer `json:"n,omitempty"`
E *byteBuffer `json:"e,omitempty"`
// -- Following fields are only used for private keys --
// RSA uses D, P and Q, while ECDSA uses only D. Fields Dp, Dq, and Qi are
// completely optional. Therefore for RSA/ECDSA, D != nil is a contract that
// we have a private key whereas D == nil means we have only a public key.
D *byteBuffer `json:"d,omitempty"`
P *byteBuffer `json:"p,omitempty"`
Q *byteBuffer `json:"q,omitempty"`
Dp *byteBuffer `json:"dp,omitempty"`
Dq *byteBuffer `json:"dq,omitempty"`
Qi *byteBuffer `json:"qi,omitempty"`
}
// JsonWebKey represents a public or private key in JWK format.
type JsonWebKey struct {
Key interface{}
KeyID string
Algorithm string
Use string
}
// MarshalJSON serializes the given key to its JSON representation.
func (k JsonWebKey) MarshalJSON() ([]byte, error) {
var raw *rawJsonWebKey
var err error
switch key := k.Key.(type) {
case *ecdsa.PublicKey:
raw, err = fromEcPublicKey(key)
case *rsa.PublicKey:
raw = fromRsaPublicKey(key)
case *ecdsa.PrivateKey:
raw, err = fromEcPrivateKey(key)
case *rsa.PrivateKey:
raw, err = fromRsaPrivateKey(key)
case []byte:
raw, err = fromSymmetricKey(key)
default:
return nil, fmt.Errorf("square/go-jose: unknown key type '%s'", reflect.TypeOf(key))
}
if err != nil {
return nil, err
}
raw.Kid = k.KeyID
raw.Alg = k.Algorithm
raw.Use = k.Use
return MarshalJSON(raw)
}
// UnmarshalJSON reads a key from its JSON representation.
func (k *JsonWebKey) UnmarshalJSON(data []byte) (err error) {
var raw rawJsonWebKey
err = UnmarshalJSON(data, &raw)
if err != nil {
return err
}
var key interface{}
switch raw.Kty {
case "EC":
if raw.D != nil {
key, err = raw.ecPrivateKey()
} else {
key, err = raw.ecPublicKey()
}
case "RSA":
if raw.D != nil {
key, err = raw.rsaPrivateKey()
} else {
key, err = raw.rsaPublicKey()
}
case "oct":
key, err = raw.symmetricKey()
default:
err = fmt.Errorf("square/go-jose: unknown json web key type '%s'", raw.Kty)
}
if err == nil {
*k = JsonWebKey{Key: key, KeyID: raw.Kid, Algorithm: raw.Alg, Use: raw.Use}
}
return
}
// JsonWebKeySet represents a JWK Set object.
type JsonWebKeySet struct {
Keys []JsonWebKey `json:"keys"`
}
// Key convenience method returns keys by key ID. Specification states
// that a JWK Set "SHOULD" use distinct key IDs, but allows for some
// cases where they are not distinct. Hence method returns a slice
// of JsonWebKeys.
func (s *JsonWebKeySet) Key(kid string) []JsonWebKey {
var keys []JsonWebKey
for _, key := range s.Keys {
if key.KeyID == kid {
keys = append(keys, key)
}
}
return keys
}
const rsaThumbprintTemplate = `{"e":"%s","kty":"RSA","n":"%s"}`
const ecThumbprintTemplate = `{"crv":"%s","kty":"EC","x":"%s","y":"%s"}`
func ecThumbprintInput(curve elliptic.Curve, x, y *big.Int) (string, error) {
coordLength := curveSize(curve)
crv, err := curveName(curve)
if err != nil {
return "", err
}
return fmt.Sprintf(ecThumbprintTemplate, crv,
newFixedSizeBuffer(x.Bytes(), coordLength).base64(),
newFixedSizeBuffer(y.Bytes(), coordLength).base64()), nil
}
func rsaThumbprintInput(n *big.Int, e int) (string, error) {
return fmt.Sprintf(rsaThumbprintTemplate,
newBufferFromInt(uint64(e)).base64(),
newBuffer(n.Bytes()).base64()), nil
}
// Thumbprint computes the JWK Thumbprint of a key using the
// indicated hash algorithm.
func (k *JsonWebKey) Thumbprint(hash crypto.Hash) ([]byte, error) {
var input string
var err error
switch key := k.Key.(type) {
case *ecdsa.PublicKey:
input, err = ecThumbprintInput(key.Curve, key.X, key.Y)
case *ecdsa.PrivateKey:
input, err = ecThumbprintInput(key.Curve, key.X, key.Y)
case *rsa.PublicKey:
input, err = rsaThumbprintInput(key.N, key.E)
case *rsa.PrivateKey:
input, err = rsaThumbprintInput(key.N, key.E)
default:
return nil, fmt.Errorf("square/go-jose: unknown key type '%s'", reflect.TypeOf(key))
}
if err != nil {
return nil, err
}
h := hash.New()
h.Write([]byte(input))
return h.Sum(nil), nil
}
// Valid checks that the key contains the expected parameters
func (k *JsonWebKey) Valid() bool {
if k.Key == nil {
return false
}
switch key := k.Key.(type) {
case *ecdsa.PublicKey:
if key.Curve == nil || key.X == nil || key.Y == nil {
return false
}
case *ecdsa.PrivateKey:
if key.Curve == nil || key.X == nil || key.Y == nil || key.D == nil {
return false
}
case *rsa.PublicKey:
if key.N == nil || key.E == 0 {
return false
}
case *rsa.PrivateKey:
if key.N == nil || key.E == 0 || key.D == nil || len(key.Primes) < 2 {
return false
}
default:
return false
}
return true
}
func (key rawJsonWebKey) rsaPublicKey() (*rsa.PublicKey, error) {
if key.N == nil || key.E == nil {
return nil, fmt.Errorf("square/go-jose: invalid RSA key, missing n/e values")
}
return &rsa.PublicKey{
N: key.N.bigInt(),
E: key.E.toInt(),
}, nil
}
func fromRsaPublicKey(pub *rsa.PublicKey) *rawJsonWebKey {
return &rawJsonWebKey{
Kty: "RSA",
N: newBuffer(pub.N.Bytes()),
E: newBufferFromInt(uint64(pub.E)),
}
}
func (key rawJsonWebKey) ecPublicKey() (*ecdsa.PublicKey, error) {
var curve elliptic.Curve
switch key.Crv {
case "P-256":
curve = elliptic.P256()
case "P-384":
curve = elliptic.P384()
case "P-521":
curve = elliptic.P521()
default:
return nil, fmt.Errorf("square/go-jose: unsupported elliptic curve '%s'", key.Crv)
}
if key.X == nil || key.Y == nil {
return nil, fmt.Errorf("square/go-jose: invalid EC key, missing x/y values")
}
return &ecdsa.PublicKey{
Curve: curve,
X: key.X.bigInt(),
Y: key.Y.bigInt(),
}, nil
}
func fromEcPublicKey(pub *ecdsa.PublicKey) (*rawJsonWebKey, error) {
if pub == nil || pub.X == nil || pub.Y == nil {
return nil, fmt.Errorf("square/go-jose: invalid EC key (nil, or X/Y missing)")
}
name, err := curveName(pub.Curve)
if err != nil {
return nil, err
}
size := curveSize(pub.Curve)
xBytes := pub.X.Bytes()
yBytes := pub.Y.Bytes()
if len(xBytes) > size || len(yBytes) > size {
return nil, fmt.Errorf("square/go-jose: invalid EC key (X/Y too large)")
}
key := &rawJsonWebKey{
Kty: "EC",
Crv: name,
X: newFixedSizeBuffer(xBytes, size),
Y: newFixedSizeBuffer(yBytes, size),
}
return key, nil
}
func (key rawJsonWebKey) rsaPrivateKey() (*rsa.PrivateKey, error) {
var missing []string
switch {
case key.N == nil:
missing = append(missing, "N")
case key.E == nil:
missing = append(missing, "E")
case key.D == nil:
missing = append(missing, "D")
case key.P == nil:
missing = append(missing, "P")
case key.Q == nil:
missing = append(missing, "Q")
}
if len(missing) > 0 {
return nil, fmt.Errorf("square/go-jose: invalid RSA private key, missing %s value(s)", strings.Join(missing, ", "))
}
rv := &rsa.PrivateKey{
PublicKey: rsa.PublicKey{
N: key.N.bigInt(),
E: key.E.toInt(),
},
D: key.D.bigInt(),
Primes: []*big.Int{
key.P.bigInt(),
key.Q.bigInt(),
},
}
if key.Dp != nil {
rv.Precomputed.Dp = key.Dp.bigInt()
}
if key.Dq != nil {
rv.Precomputed.Dq = key.Dq.bigInt()
}
if key.Qi != nil {
rv.Precomputed.Qinv = key.Qi.bigInt()
}
err := rv.Validate()
return rv, err
}
func fromRsaPrivateKey(rsa *rsa.PrivateKey) (*rawJsonWebKey, error) {
if len(rsa.Primes) != 2 {
return nil, ErrUnsupportedKeyType
}
raw := fromRsaPublicKey(&rsa.PublicKey)
raw.D = newBuffer(rsa.D.Bytes())
raw.P = newBuffer(rsa.Primes[0].Bytes())
raw.Q = newBuffer(rsa.Primes[1].Bytes())
return raw, nil
}
func (key rawJsonWebKey) ecPrivateKey() (*ecdsa.PrivateKey, error) {
var curve elliptic.Curve
switch key.Crv {
case "P-256":
curve = elliptic.P256()
case "P-384":
curve = elliptic.P384()
case "P-521":
curve = elliptic.P521()
default:
return nil, fmt.Errorf("square/go-jose: unsupported elliptic curve '%s'", key.Crv)
}
if key.X == nil || key.Y == nil || key.D == nil {
return nil, fmt.Errorf("square/go-jose: invalid EC private key, missing x/y/d values")
}
return &ecdsa.PrivateKey{
PublicKey: ecdsa.PublicKey{
Curve: curve,
X: key.X.bigInt(),
Y: key.Y.bigInt(),
},
D: key.D.bigInt(),
}, nil
}
func fromEcPrivateKey(ec *ecdsa.PrivateKey) (*rawJsonWebKey, error) {
raw, err := fromEcPublicKey(&ec.PublicKey)
if err != nil {
return nil, err
}
if ec.D == nil {
return nil, fmt.Errorf("square/go-jose: invalid EC private key")
}
raw.D = newBuffer(ec.D.Bytes())
return raw, nil
}
func fromSymmetricKey(key []byte) (*rawJsonWebKey, error) {
return &rawJsonWebKey{
Kty: "oct",
K: newBuffer(key),
}, nil
}
func (key rawJsonWebKey) symmetricKey() ([]byte, error) {
if key.K == nil {
return nil, fmt.Errorf("square/go-jose: invalid OCT (symmetric) key, missing k value")
}
return key.K.bytes(), nil
}