zitadel-oidc/pkg/oidc/keyset.go
Livio Amstutz a63fbee93d
fix: improve JWS and key verification (#128)
* fix: improve JWS and key verification

* fix: get remote keys if no cached key matches

* fix: get remote keys if no cached key matches

* fix exactMatch

* fix exactMatch

* chore: change default branch name in .releaserc.js
2021-09-14 15:13:44 +02:00

96 lines
2.6 KiB
Go

package oidc
import (
"context"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"errors"
"gopkg.in/square/go-jose.v2"
)
const (
KeyUseSignature = "sig"
)
var (
ErrKeyMultiple = errors.New("multiple possible keys match")
ErrKeyNone = errors.New("no possible keys matches")
)
//KeySet represents a set of JSON Web Keys
// - remotely fetch via discovery and jwks_uri -> `remoteKeySet`
// - held by the OP itself in storage -> `openIDKeySet`
// - dynamically aggregated by request for OAuth JWT Profile Assertion -> `jwtProfileKeySet`
type KeySet interface {
//VerifySignature verifies the signature with the given keyset and returns the raw payload
VerifySignature(ctx context.Context, jws *jose.JSONWebSignature) (payload []byte, err error)
}
//GetKeyIDAndAlg returns the `kid` and `alg` claim from the JWS header
func GetKeyIDAndAlg(jws *jose.JSONWebSignature) (string, string) {
keyID := ""
alg := ""
for _, sig := range jws.Signatures {
keyID = sig.Header.KeyID
alg = sig.Header.Algorithm
break
}
return keyID, alg
}
//FindKey searches the given JSON Web Keys for the requested key ID, usage and key type
//
//will return the key immediately if matches exact (id, usage, type)
//
//will return false none or multiple match
//
//deprecated: use FindMatchingKey which will return an error (more specific) instead of just a bool
//moved implementation already to FindMatchingKey
func FindKey(keyID, use, expectedAlg string, keys ...jose.JSONWebKey) (jose.JSONWebKey, bool) {
key, err := FindMatchingKey(keyID, use, expectedAlg, keys...)
return key, err == nil
}
//FindMatchingKey searches the given JSON Web Keys for the requested key ID, usage and key type
//
//will return the key immediately if matches exact (id, usage, type)
//
//will return a specific error if none (ErrKeyNone) or multiple (ErrKeyMultiple) match
func FindMatchingKey(keyID, use, expectedAlg string, keys ...jose.JSONWebKey) (key jose.JSONWebKey, err error) {
var validKeys []jose.JSONWebKey
for _, k := range keys {
if k.Use == use && algToKeyType(k.Key, expectedAlg) {
if k.KeyID == keyID && keyID != "" {
return k, nil
}
if k.KeyID == "" || keyID == "" {
validKeys = append(validKeys, k)
}
}
}
if len(validKeys) == 1 {
return validKeys[0], nil
}
if len(validKeys) > 1 {
return key, ErrKeyMultiple
}
return key, ErrKeyNone
}
func algToKeyType(key interface{}, alg string) bool {
switch alg[0] {
case 'R', 'P':
_, ok := key.(*rsa.PublicKey)
return ok
case 'E':
_, ok := key.(*ecdsa.PublicKey)
return ok
case 'O':
_, ok := key.(*ed25519.PublicKey)
return ok
default:
return false
}
}