woodpecker/vendor/github.com/square/go-jose/jwk.go
2015-09-29 17:34:44 -07:00

275 lines
6.5 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/ecdsa"
"crypto/elliptic"
"crypto/rsa"
"encoding/json"
"fmt"
"math/big"
"reflect"
)
// rawJsonWebKey represents a public or private key in JWK format, used for parsing/serializing.
type rawJsonWebKey struct {
Kty string `json:"kty,omitempty"`
Kid string `json:"kid,omitempty"`
Crv string `json:"crv,omitempty"`
Alg string `json:"alg,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
}
// 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)
default:
return nil, fmt.Errorf("square/go-jose: unkown key type '%s'", reflect.TypeOf(key))
}
if err != nil {
return nil, err
}
raw.Kid = k.KeyID
raw.Alg = k.Algorithm
return json.Marshal(raw)
}
// UnmarshalJSON reads a key from its JSON representation.
func (k *JsonWebKey) UnmarshalJSON(data []byte) (err error) {
var raw rawJsonWebKey
err = json.Unmarshal(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()
}
default:
err = fmt.Errorf("square/go-jose: unkown json web key type '%s'", raw.Kty)
}
if err == nil {
*k = JsonWebKey{Key: key, KeyID: raw.Kid, Algorithm: raw.Alg}
}
return
}
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) {
if key.N == nil || key.E == nil || key.D == nil || key.P == nil || key.Q == nil {
return nil, fmt.Errorf("square/go-jose: invalid RSA private key, missing values")
}
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
}