rename all remaining packages to internal/ (#12418)

This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`

internal/config/identity/openid/jwks.go

@@ -0,0 +1,122 @@
+// 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)
+	}
+}