minio/cmd/config/identity/openid/jwks.go

123 lines
2.9 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package openid
import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rsa"
"encoding/base64"
"errors"
"fmt"
"math/big"
)
// JWKS - https://tools.ietf.org/html/rfc7517
type JWKS struct {
Keys []*JWKS `json:"keys,omitempty"`
Kty string `json:"kty"`
Use string `json:"use,omitempty"`
Kid string `json:"kid,omitempty"`
Alg string `json:"alg,omitempty"`
Crv string `json:"crv,omitempty"`
X string `json:"x,omitempty"`
Y string `json:"y,omitempty"`
D string `json:"d,omitempty"`
N string `json:"n,omitempty"`
E string `json:"e,omitempty"`
K string `json:"k,omitempty"`
}
var (
errMalformedJWKRSAKey = errors.New("malformed JWK RSA key")
errMalformedJWKECKey = errors.New("malformed JWK EC key")
)
// DecodePublicKey - decodes JSON Web Key (JWK) as public key
func (key *JWKS) DecodePublicKey() (crypto.PublicKey, error) {
switch key.Kty {
case "RSA":
if key.N == "" || key.E == "" {
return nil, errMalformedJWKRSAKey
}
// decode exponent
ebuf, err := base64.RawURLEncoding.DecodeString(key.E)
if err != nil {
return nil, errMalformedJWKRSAKey
}
nbuf, err := base64.RawURLEncoding.DecodeString(key.N)
if err != nil {
return nil, errMalformedJWKRSAKey
}
var n, e big.Int
n.SetBytes(nbuf)
e.SetBytes(ebuf)
return &rsa.PublicKey{
E: int(e.Int64()),
N: &n,
}, nil
case "EC":
if key.Crv == "" || key.X == "" || key.Y == "" {
return nil, errMalformedJWKECKey
}
var curve elliptic.Curve
switch key.Crv {
case "P-224":
curve = elliptic.P224()
case "P-256":
curve = elliptic.P256()
case "P-384":
curve = elliptic.P384()
case "P-521":
curve = elliptic.P521()
default:
return nil, fmt.Errorf("Unknown curve type: %s", key.Crv)
}
xbuf, err := base64.RawURLEncoding.DecodeString(key.X)
if err != nil {
return nil, errMalformedJWKECKey
}
ybuf, err := base64.RawURLEncoding.DecodeString(key.Y)
if err != nil {
return nil, errMalformedJWKECKey
}
var x, y big.Int
x.SetBytes(xbuf)
y.SetBytes(ybuf)
return &ecdsa.PublicKey{
Curve: curve,
X: &x,
Y: &y,
}, nil
default:
return nil, fmt.Errorf("Unknown JWK key type %s", key.Kty)
}
}