1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
// Copyright 2024 OpenPubkey
//
// 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.
//
// SPDX-License-Identifier: Apache-2.0
package jwks
import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"encoding/hex"
"encoding/json"
"fmt"
"net"
"net/http"
"github.com/lestrrat-go/jwx/v2/jwa"
"github.com/lestrrat-go/jwx/v2/jwk"
"golang.org/x/crypto/sha3"
)
type JwksServer struct {
uri string
jwksBytes []byte
}
// A very simple JWKS server for our MFA Cosigner example code.
func NewJwksServer(signer crypto.Signer, alg jwa.SignatureAlgorithm) (*JwksServer, string, error) {
// Compute the kid (Key ID) as the SHA-3 of the public key
pubkey := signer.Public().(*ecdsa.PublicKey) // TODO: handle non-ecdsa signers
pubkeyBytes := elliptic.Marshal(pubkey, pubkey.X, pubkey.Y)
pubkeyHash := sha3.Sum256(pubkeyBytes)
kid := hex.EncodeToString(pubkeyHash[:])
// Generate our JWKS using our signing key
jwkKey, err := jwk.PublicKeyOf(signer)
if err != nil {
return nil, "", err
}
jwkKey.Set(jwk.AlgorithmKey, alg)
jwkKey.Set(jwk.KeyIDKey, kid)
// Put our jwk into a set
keySet := jwk.NewSet()
keySet.AddKey(jwkKey)
// Now convert our key set into the raw bytes for printing later
keySetBytes, _ := json.MarshalIndent(keySet, "", " ")
if err != nil {
return nil, "", err
}
// Find an empty port
listener, err := net.Listen("tcp", ":0")
if err != nil {
return nil, "", fmt.Errorf("failed to bind to an available port: %w", err)
}
server := &JwksServer{
uri: fmt.Sprintf("http://localhost:%d", listener.Addr().(*net.TCPAddr).Port),
jwksBytes: keySetBytes,
}
// Host our JWKS at a localhost url
mux := http.NewServeMux()
mux.HandleFunc("/.well-known/jwks.json", server.printJWKS)
go func() {
http.Serve(listener, mux)
}()
return server, kid, nil
}
func (s *JwksServer) URI() string {
return s.uri
}
func (s *JwksServer) printJWKS(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
w.Write(s.jwksBytes)
}
|
