/
jwks_writer.go
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/
jwks_writer.go
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// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
package supervisorconfig
import (
"context"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"encoding/json"
"fmt"
"io"
"gopkg.in/square/go-jose.v2"
corev1 "k8s.io/api/core/v1"
k8serrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime/schema"
corev1informers "k8s.io/client-go/informers/core/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/util/retry"
"k8s.io/klog/v2"
configv1alpha1 "go.pinniped.dev/generated/latest/apis/supervisor/config/v1alpha1"
pinnipedclientset "go.pinniped.dev/generated/latest/client/supervisor/clientset/versioned"
configinformers "go.pinniped.dev/generated/latest/client/supervisor/informers/externalversions/config/v1alpha1"
pinnipedcontroller "go.pinniped.dev/internal/controller"
"go.pinniped.dev/internal/controller/supervisorconfig/generator"
"go.pinniped.dev/internal/controllerlib"
"go.pinniped.dev/internal/plog"
)
// These constants are the keys in a FederationDomain's Secret's Data map.
const (
// activeJWKKey points to the current private key used for signing tokens.
//
// Note! The value for this key will contain private key material!
activeJWKKey = "activeJWK"
// jwksKey points to the current JWKS used to verify tokens.
//
// Note! The value for this key will contain only public key material!
jwksKey = "jwks"
jwksSecretTypeValue corev1.SecretType = "secrets.pinniped.dev/federation-domain-jwks"
)
const (
federationDomainKind = "FederationDomain"
)
// generateKey is stubbed out for the purpose of testing. The default behavior is to generate an EC key.
//nolint:gochecknoglobals
var generateKey func(r io.Reader) (interface{}, error) = generateECKey
func generateECKey(r io.Reader) (interface{}, error) {
return ecdsa.GenerateKey(elliptic.P256(), r)
}
// jwkController holds the fields necessary for the JWKS controller to communicate with FederationDomains and
// secrets, both via a cache and via the API.
type jwksWriterController struct {
jwksSecretLabels map[string]string
pinnipedClient pinnipedclientset.Interface
kubeClient kubernetes.Interface
federationDomainInformer configinformers.FederationDomainInformer
secretInformer corev1informers.SecretInformer
}
// NewJWKSWriterController returns a controllerlib.Controller that ensures a FederationDomain has a corresponding
// Secret that contains a valid active JWK and JWKS.
func NewJWKSWriterController(
jwksSecretLabels map[string]string,
kubeClient kubernetes.Interface,
pinnipedClient pinnipedclientset.Interface,
secretInformer corev1informers.SecretInformer,
federationDomainInformer configinformers.FederationDomainInformer,
withInformer pinnipedcontroller.WithInformerOptionFunc,
) controllerlib.Controller {
isSecretToSync := func(obj metav1.Object) bool {
return generator.IsFederationDomainSecretOfType(obj, jwksSecretTypeValue)
}
return controllerlib.New(
controllerlib.Config{
Name: "JWKSController",
Syncer: &jwksWriterController{
jwksSecretLabels: jwksSecretLabels,
kubeClient: kubeClient,
pinnipedClient: pinnipedClient,
secretInformer: secretInformer,
federationDomainInformer: federationDomainInformer,
},
},
// We want to be notified when a FederationDomain's secret gets updated or deleted. When this happens, we
// should get notified via the corresponding FederationDomain key.
withInformer(
secretInformer,
pinnipedcontroller.SimpleFilter(isSecretToSync, pinnipedcontroller.SecretIsControlledByParentFunc(isSecretToSync)),
controllerlib.InformerOption{},
),
// We want to be notified when anything happens to an FederationDomain.
withInformer(
federationDomainInformer,
pinnipedcontroller.MatchAnythingFilter(nil), // nil parent func is fine because each event is distinct
controllerlib.InformerOption{},
),
)
}
// Sync implements controllerlib.Syncer.
func (c *jwksWriterController) Sync(ctx controllerlib.Context) error {
federationDomain, err := c.federationDomainInformer.Lister().FederationDomains(ctx.Key.Namespace).Get(ctx.Key.Name)
notFound := k8serrors.IsNotFound(err)
if err != nil && !notFound {
return fmt.Errorf(
"failed to get %s/%s FederationDomain: %w",
ctx.Key.Namespace,
ctx.Key.Name,
err,
)
}
if notFound {
// The corresponding secret to this FederationDomain should have been garbage collected since it should have
// had this FederationDomain as its owner.
plog.Debug(
"FederationDomain deleted",
"federationdomain",
klog.KRef(ctx.Key.Namespace, ctx.Key.Name),
)
return nil
}
secretNeedsUpdate, err := c.secretNeedsUpdate(federationDomain)
if err != nil {
return fmt.Errorf("cannot determine secret status: %w", err)
}
if !secretNeedsUpdate {
// Secret is up to date - we are good to go.
plog.Debug(
"secret is up to date",
"federationdomain",
klog.KRef(ctx.Key.Namespace, ctx.Key.Name),
)
return nil
}
// If the FederationDomain does not have a secret associated with it, that secret does not exist, or the secret
// is invalid, we will generate a new secret (i.e., a JWKS).
secret, err := c.generateSecret(federationDomain)
if err != nil {
return fmt.Errorf("cannot generate secret: %w", err)
}
if err := c.createOrUpdateSecret(ctx.Context, secret); err != nil {
return fmt.Errorf("cannot create or update secret: %w", err)
}
plog.Debug("created/updated secret", "secret", klog.KObj(secret))
// Ensure that the FederationDomain points to the secret.
newFederationDomain := federationDomain.DeepCopy()
newFederationDomain.Status.Secrets.JWKS.Name = secret.Name
if err := c.updateFederationDomainStatus(ctx.Context, newFederationDomain); err != nil {
return fmt.Errorf("cannot update FederationDomain: %w", err)
}
plog.Debug("updated FederationDomain", "federationdomain", klog.KObj(newFederationDomain))
return nil
}
func (c *jwksWriterController) secretNeedsUpdate(federationDomain *configv1alpha1.FederationDomain) (bool, error) {
if federationDomain.Status.Secrets.JWKS.Name == "" {
// If the FederationDomain says it doesn't have a secret associated with it, then let's create one.
return true, nil
}
// This FederationDomain says it has a secret associated with it. Let's try to get it from the cache.
secret, err := c.secretInformer.Lister().Secrets(federationDomain.Namespace).Get(federationDomain.Status.Secrets.JWKS.Name)
notFound := k8serrors.IsNotFound(err)
if err != nil && !notFound {
return false, fmt.Errorf("cannot get secret: %w", err)
}
if notFound {
// If we can't find the secret, let's assume we need to create it.
return true, nil
}
if !isValid(secret) {
// If this secret is invalid, we need to generate a new one.
return true, nil
}
return false, nil
}
func (c *jwksWriterController) generateSecret(federationDomain *configv1alpha1.FederationDomain) (*corev1.Secret, error) {
// Note! This is where we could potentially add more handling of FederationDomain spec fields which tell us how
// this FederationDomain should sign and verify ID tokens (e.g., hardcoded token secret, gRPC
// connection to KMS, etc).
//
// For now, we just generate an new RSA keypair and put that in the secret.
key, err := generateKey(rand.Reader)
if err != nil {
return nil, fmt.Errorf("cannot generate key: %w", err)
}
jwk := jose.JSONWebKey{
Key: key,
KeyID: "pinniped-supervisor-key",
Algorithm: "ES256",
Use: "sig",
}
jwkData, err := json.Marshal(jwk)
if err != nil {
return nil, fmt.Errorf("cannot marshal jwk: %w", err)
}
jwks := jose.JSONWebKeySet{
Keys: []jose.JSONWebKey{jwk.Public()},
}
jwksData, err := json.Marshal(jwks)
if err != nil {
return nil, fmt.Errorf("cannot marshal jwks: %w", err)
}
s := corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: federationDomain.Name + "-jwks",
Namespace: federationDomain.Namespace,
Labels: c.jwksSecretLabels,
OwnerReferences: []metav1.OwnerReference{
*metav1.NewControllerRef(federationDomain, schema.GroupVersionKind{
Group: configv1alpha1.SchemeGroupVersion.Group,
Version: configv1alpha1.SchemeGroupVersion.Version,
Kind: federationDomainKind,
}),
},
},
Data: map[string][]byte{
activeJWKKey: jwkData,
jwksKey: jwksData,
},
Type: jwksSecretTypeValue,
}
return &s, nil
}
func (c *jwksWriterController) createOrUpdateSecret(
ctx context.Context,
newSecret *corev1.Secret,
) error {
secretClient := c.kubeClient.CoreV1().Secrets(newSecret.Namespace)
return retry.RetryOnConflict(retry.DefaultRetry, func() error {
oldSecret, err := secretClient.Get(ctx, newSecret.Name, metav1.GetOptions{})
notFound := k8serrors.IsNotFound(err)
if err != nil && !notFound {
return fmt.Errorf("cannot get secret: %w", err)
}
if notFound {
// New secret doesn't exist, so create it.
_, err := secretClient.Create(ctx, newSecret, metav1.CreateOptions{})
if err != nil {
return fmt.Errorf("cannot create secret: %w", err)
}
return nil
}
// New secret already exists, so ensure it is up to date.
if isValid(oldSecret) {
// If the secret already has valid JWK's, then we are good to go and we don't need an update.
return nil
}
oldSecret.Data = newSecret.Data
oldSecret.Type = jwksSecretTypeValue
_, err = secretClient.Update(ctx, oldSecret, metav1.UpdateOptions{})
return err
})
}
func (c *jwksWriterController) updateFederationDomainStatus(
ctx context.Context,
newFederationDomain *configv1alpha1.FederationDomain,
) error {
federationDomainClient := c.pinnipedClient.ConfigV1alpha1().FederationDomains(newFederationDomain.Namespace)
return retry.RetryOnConflict(retry.DefaultRetry, func() error {
oldFederationDomain, err := federationDomainClient.Get(ctx, newFederationDomain.Name, metav1.GetOptions{})
if err != nil {
return fmt.Errorf("cannot get FederationDomain: %w", err)
}
if newFederationDomain.Status.Secrets.JWKS.Name == oldFederationDomain.Status.Secrets.JWKS.Name {
// If the existing FederationDomain is up to date, we don't need to update it.
return nil
}
oldFederationDomain.Status.Secrets.JWKS.Name = newFederationDomain.Status.Secrets.JWKS.Name
_, err = federationDomainClient.UpdateStatus(ctx, oldFederationDomain, metav1.UpdateOptions{})
return err
})
}
// isValid returns whether the provided secret contains a valid active JWK and verification JWKS.
func isValid(secret *corev1.Secret) bool {
if secret.Type != jwksSecretTypeValue {
plog.Debug("secret does not have the expected type", "expectedType", jwksSecretTypeValue, "actualType", secret.Type)
return false
}
jwkData, ok := secret.Data[activeJWKKey]
if !ok {
plog.Debug("secret does not contain active jwk")
return false
}
var activeJWK jose.JSONWebKey
if err := json.Unmarshal(jwkData, &activeJWK); err != nil {
plog.Debug("cannot unmarshal active jwk", "err", err)
return false
}
if activeJWK.IsPublic() {
plog.Debug("active jwk is public", "keyid", activeJWK.KeyID)
return false
}
if !activeJWK.Valid() {
plog.Debug("active jwk is not valid", "keyid", activeJWK.KeyID)
return false
}
jwksData, ok := secret.Data[jwksKey]
if !ok {
plog.Debug("secret does not contain valid jwks")
}
var validJWKS jose.JSONWebKeySet
if err := json.Unmarshal(jwksData, &validJWKS); err != nil {
plog.Debug("cannot unmarshal valid jwks", "err", err)
return false
}
foundActiveJWK := false
for _, validJWK := range validJWKS.Keys {
if !validJWK.IsPublic() {
plog.Debug("jwks key is not public", "keyid", validJWK.KeyID)
return false
}
if !validJWK.Valid() {
plog.Debug("jwks key is not valid", "keyid", validJWK.KeyID)
return false
}
if validJWK.KeyID == activeJWK.KeyID {
foundActiveJWK = true
}
}
if !foundActiveJWK {
plog.Debug("did not find active jwk in valid jwks", "keyid", activeJWK.KeyID)
return false
}
return true
}