/
webhook.go
405 lines (365 loc) · 13.5 KB
/
webhook.go
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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
package webhook
import (
"context"
"crypto/tls"
"crypto/x509"
"encoding/json"
"fmt"
"net/http"
"reflect"
"sort"
"strings"
"time"
"github.com/go-openapi/inflect"
"go.uber.org/zap"
admissionv1 "k8s.io/api/admission/v1"
admissionregistrationv1 "k8s.io/api/admissionregistration/v1"
appsv1 "k8s.io/api/apps/v1"
corev1 "k8s.io/api/core/v1"
rbacv1 "k8s.io/api/rbac/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/client-go/kubernetes"
clientadmissionregistrationv1 "k8s.io/client-go/kubernetes/typed/admissionregistration/v1"
"github.com/argoproj/argo-events/common/logging"
commontls "github.com/argoproj/argo-events/common/tls"
eventbusclient "github.com/argoproj/argo-events/pkg/client/eventbus/clientset/versioned"
eventsourceclient "github.com/argoproj/argo-events/pkg/client/eventsource/clientset/versioned"
sensorclient "github.com/argoproj/argo-events/pkg/client/sensor/clientset/versioned"
"github.com/argoproj/argo-events/webhook/validator"
)
const (
secretServerKey = "server-key.pem"
secretServerCert = "server-cert.pem"
secretCACert = "ca-cert.pem"
certOrg = "io.argoproj"
)
// Options contains the configuration for the webhook
type Options struct {
// WebhookName is the name of the webhook
WebhookName string
// ServiceName is the service name of the webhook.
ServiceName string
// DeploymentName is the deployment name of the webhook.
DeploymentName string
// ClusterRoleName is the cluster role name of the webhook
ClusterRoleName string
// SecretName is the name of k8s secret that contains the webhook
// server key/cert and corresponding CA cert that signed them. The
// server key/cert are used to serve the webhook and the CA cert
// is provided to k8s apiserver during admission controller
// registration.
SecretName string
// Namespace is the namespace in which everything above lives
Namespace string
// Port where the webhook is served. Per k8s admission
// registration requirements this should be 443 unless there is
// only a single port for the service.
Port int
// ClientAuthType declares the policy the webhook server will follow for
// TLS Client Authentication.
// The default value is tls.NoClientCert.
ClientAuth tls.ClientAuthType
}
// AdmissionController implements a webhook for validation
type AdmissionController struct {
Client kubernetes.Interface
EventBusClient eventbusclient.Interface
EventSourceClient eventsourceclient.Interface
SensorClient sensorclient.Interface
Options Options
Handlers map[schema.GroupVersionKind]runtime.Object
Logger *zap.SugaredLogger
}
// Run implements the admission controller run loop.
func (ac *AdmissionController) Run(ctx context.Context) error {
logger := ac.Logger
tlsConfig, caCert, err := ac.configureCerts(ctx, ac.Options.ClientAuth)
if err != nil {
logger.Errorw("Could not configure admission webhook certs", zap.Error(err))
return err
}
server := &http.Server{
Handler: ac,
Addr: fmt.Sprintf(":%v", ac.Options.Port),
TLSConfig: tlsConfig,
}
cl := ac.Client.AdmissionregistrationV1().ValidatingWebhookConfigurations()
if err := ac.register(ctx, cl, caCert); err != nil {
logger.Errorw("Failed to register webhook", zap.Error(err))
return err
}
logger.Info("Successfully registered webhook")
serverStartErrCh := make(chan struct{})
go func() {
if err := server.ListenAndServeTLS("", ""); err != nil {
logger.Errorw("ListenAndServeTLS for admission webhook errored out", zap.Error(err))
close(serverStartErrCh)
}
}()
select {
case <-ctx.Done():
return server.Close()
case <-serverStartErrCh:
return fmt.Errorf("webhook server failed to start")
}
}
// Register registers the validating admission webhook
func (ac *AdmissionController) register(
ctx context.Context, client clientadmissionregistrationv1.ValidatingWebhookConfigurationInterface, caCert []byte) error {
failurePolicy := admissionregistrationv1.Ignore
var rules []admissionregistrationv1.RuleWithOperations
for gvk := range ac.Handlers {
plural := strings.ToLower(inflect.Pluralize(gvk.Kind))
rules = append(rules, admissionregistrationv1.RuleWithOperations{
Operations: []admissionregistrationv1.OperationType{
admissionregistrationv1.Create,
admissionregistrationv1.Update,
admissionregistrationv1.Delete,
},
Rule: admissionregistrationv1.Rule{
APIGroups: []string{gvk.Group},
APIVersions: []string{gvk.Version},
Resources: []string{plural},
},
})
}
// sort
sort.Slice(rules, func(i, j int) bool {
lhs, rhs := rules[i], rules[j]
if lhs.APIGroups[0] != rhs.APIGroups[0] {
return lhs.APIGroups[0] < rhs.APIGroups[0]
}
if lhs.APIVersions[0] != rhs.APIVersions[0] {
return lhs.APIVersions[0] < rhs.APIVersions[0]
}
return lhs.Resources[0] < rhs.Resources[0]
})
sideEffects := admissionregistrationv1.SideEffectClassNone
port := int32(ac.Options.Port)
webhook := &admissionregistrationv1.ValidatingWebhookConfiguration{
ObjectMeta: metav1.ObjectMeta{
Name: ac.Options.WebhookName,
},
Webhooks: []admissionregistrationv1.ValidatingWebhook{{
Name: ac.Options.WebhookName,
Rules: rules,
SideEffects: &sideEffects,
AdmissionReviewVersions: []string{"v1", "v1beta1"},
ClientConfig: admissionregistrationv1.WebhookClientConfig{
Service: &admissionregistrationv1.ServiceReference{
Namespace: ac.Options.Namespace,
Name: ac.Options.ServiceName,
Port: &port,
},
CABundle: caCert,
},
FailurePolicy: &failurePolicy,
}},
}
clusterRole, err := ac.Client.RbacV1().ClusterRoles().Get(ctx, ac.Options.ClusterRoleName, metav1.GetOptions{})
if err != nil {
return fmt.Errorf("failed to fetch webhook cluster role, %w", err)
}
clusterRoleRef := metav1.NewControllerRef(clusterRole, rbacv1.SchemeGroupVersion.WithKind("ClusterRole"))
webhook.OwnerReferences = append(webhook.OwnerReferences, *clusterRoleRef)
_, err = client.Create(ctx, webhook, metav1.CreateOptions{})
if err != nil {
if !apierrors.IsAlreadyExists(err) {
return fmt.Errorf("failed to create a webhook, %w", err)
}
ac.Logger.Info("Webhook already exists")
configuredWebhook, err := client.Get(ctx, ac.Options.WebhookName, metav1.GetOptions{})
if err != nil {
return fmt.Errorf("failed to retrieve webhook, %w", err)
}
if !reflect.DeepEqual(configuredWebhook.Webhooks, webhook.Webhooks) {
ac.Logger.Info("Updating webhook")
// Set the ResourceVersion as required by update.
webhook.ObjectMeta.ResourceVersion = configuredWebhook.ObjectMeta.ResourceVersion
if _, err := client.Update(ctx, webhook, metav1.UpdateOptions{}); err != nil {
return fmt.Errorf("failed to update webhook, %w", err)
}
} else {
ac.Logger.Info("Webhook is valid")
}
} else {
ac.Logger.Info("Created a webhook")
}
return nil
}
// ServeHTTP implements the validating admission webhook
func (ac *AdmissionController) ServeHTTP(w http.ResponseWriter, r *http.Request) {
ac.Logger.Infof("Webhook ServeHTTP request=%#v", r)
// content type validation
contentType := r.Header.Get("Content-Type")
if contentType != "application/json" {
http.Error(w, "invalid Content-Type, want `application/json`", http.StatusUnsupportedMediaType)
return
}
var review admissionv1.AdmissionReview
defer r.Body.Close()
if err := json.NewDecoder(r.Body).Decode(&review); err != nil {
http.Error(w, fmt.Sprintf("could not decode body: %v", err), http.StatusBadRequest)
return
}
logger := ac.Logger.With("kind", fmt.Sprint(review.Request.Kind)).
With("namespace", review.Request.Namespace).
With("name", review.Request.Name).
With("operation", fmt.Sprint(review.Request.Operation)).
With("resource", fmt.Sprint(review.Request.Resource)).
With("subResource", fmt.Sprint(review.Request.SubResource)).
With("userInfo", fmt.Sprint(review.Request.UserInfo))
reviewResponse := ac.admit(logging.WithLogger(r.Context(), logger), review.Request)
response := admissionv1.AdmissionReview{
TypeMeta: metav1.TypeMeta{
Kind: "AdmissionReview",
APIVersion: "admission.k8s.io/v1",
},
}
if reviewResponse != nil {
response.Response = reviewResponse
response.Response.UID = review.Request.UID
}
logger.Infof("AdmissionReview for %s: %v/%v response=%v",
review.Request.Kind, review.Request.Namespace, review.Request.Name, reviewResponse)
if err := json.NewEncoder(w).Encode(response); err != nil {
http.Error(w, fmt.Sprintf("could not encode response: %v", err), http.StatusInternalServerError)
return
}
}
func (ac *AdmissionController) admit(ctx context.Context, request *admissionv1.AdmissionRequest) *admissionv1.AdmissionResponse {
log := logging.FromContext(ctx)
switch request.Operation {
case admissionv1.Create, admissionv1.Update:
default:
log.Infof("Operation not interested: %v %v", request.Kind, request.Operation)
return &admissionv1.AdmissionResponse{Allowed: true}
}
v, err := validator.GetValidator(ctx, ac.Client, ac.EventBusClient, ac.EventSourceClient, ac.SensorClient,
request.Kind, request.OldObject.Raw, request.Object.Raw)
if err != nil {
return validator.DeniedResponse("failed to get a validator: %v", err)
}
switch request.Operation {
case admissionv1.Create:
return v.ValidateCreate(ctx)
case admissionv1.Update:
return v.ValidateUpdate(ctx)
default:
return validator.AllowedResponse()
}
}
// Generate cert secret
func (ac *AdmissionController) generateSecret(ctx context.Context) (*corev1.Secret, error) {
hosts := []string{}
hosts = append(hosts, fmt.Sprintf("%s.%s.svc.cluster.local", ac.Options.ServiceName, ac.Options.Namespace))
hosts = append(hosts, fmt.Sprintf("%s.%s.svc", ac.Options.ServiceName, ac.Options.Namespace))
serverKey, serverCert, caCert, err := commontls.CreateCerts(certOrg, hosts, time.Now().Add(10*365*24*time.Hour), true, false)
if err != nil {
return nil, err
}
deployment, err := ac.Client.AppsV1().Deployments(ac.Options.Namespace).Get(ctx, ac.Options.DeploymentName, metav1.GetOptions{})
if err != nil {
return nil, fmt.Errorf("Failed to fetch webhook deployment, %w", err)
}
deploymentRef := metav1.NewControllerRef(deployment, appsv1.SchemeGroupVersion.WithKind("Deployment"))
secret := &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: ac.Options.SecretName,
Namespace: ac.Options.Namespace,
},
Data: map[string][]byte{
secretServerKey: serverKey,
secretServerCert: serverCert,
secretCACert: caCert,
},
}
secret.OwnerReferences = append(secret.OwnerReferences, *deploymentRef)
return secret, nil
}
// getOrGenerateKeyCertsFromSecret creates CERTs if not existing and store in a secret
func (ac *AdmissionController) getOrGenerateKeyCertsFromSecret(ctx context.Context) (serverKey, serverCert, caCert []byte, err error) {
secret, err := ac.Client.CoreV1().Secrets(ac.Options.Namespace).Get(ctx, ac.Options.SecretName, metav1.GetOptions{})
if err != nil {
if !apierrors.IsNotFound(err) {
return nil, nil, nil, err
}
// No existing secret, creating one
newSecret, err := ac.generateSecret(ctx)
if err != nil {
return nil, nil, nil, err
}
_, err = ac.Client.CoreV1().Secrets(newSecret.Namespace).Create(ctx, newSecret, metav1.CreateOptions{})
if err != nil && !apierrors.IsAlreadyExists(err) {
return nil, nil, nil, err
}
// Something else might have created, try fetching it one more time
secret, err = ac.Client.CoreV1().Secrets(ac.Options.Namespace).Get(ctx, ac.Options.SecretName, metav1.GetOptions{})
if err != nil {
return nil, nil, nil, err
}
}
var ok bool
if serverKey, ok = secret.Data[secretServerKey]; !ok {
return nil, nil, nil, fmt.Errorf("server key missing")
}
if serverCert, ok = secret.Data[secretServerCert]; !ok {
return nil, nil, nil, fmt.Errorf("server cert missing")
}
if caCert, ok = secret.Data[secretCACert]; !ok {
return nil, nil, nil, fmt.Errorf("ca cert missing")
}
return serverKey, serverCert, caCert, nil
}
// GetAPIServerExtensionCACert gets the K8s aggregate apiserver
// client CA cert used by validator. This certificate is provided by
// kubernetes.
func (ac *AdmissionController) getAPIServerExtensionCACert(ctx context.Context) ([]byte, error) {
const name = "extension-apiserver-authentication"
c, err := ac.Client.CoreV1().ConfigMaps(metav1.NamespaceSystem).Get(ctx, name, metav1.GetOptions{})
if err != nil {
return nil, err
}
const caFileName = "requestheader-client-ca-file"
pem, ok := c.Data[caFileName]
if !ok {
return nil, fmt.Errorf("cannot find %s in ConfigMap %s", caFileName, name)
}
return []byte(pem), nil
}
func (ac *AdmissionController) configureCerts(ctx context.Context, clientAuth tls.ClientAuthType) (*tls.Config, []byte, error) {
var apiServerCACert []byte
if clientAuth >= tls.VerifyClientCertIfGiven {
var err error
apiServerCACert, err = ac.getAPIServerExtensionCACert(ctx)
if err != nil {
return nil, nil, err
}
}
serverKey, serverCert, caCert, err := ac.getOrGenerateKeyCertsFromSecret(ctx)
if err != nil {
return nil, nil, err
}
tlsConfig, err := makeTLSConfig(serverCert, serverKey, apiServerCACert, clientAuth)
if err != nil {
return nil, nil, err
}
return tlsConfig, caCert, nil
}
// makeTLSConfig makes a TLS configuration
func makeTLSConfig(serverCert, serverKey, caCert []byte, clientAuthType tls.ClientAuthType) (*tls.Config, error) {
caCertPool := x509.NewCertPool()
caCertPool.AppendCertsFromPEM(caCert)
cert, err := tls.X509KeyPair(serverCert, serverKey)
if err != nil {
return nil, err
}
return &tls.Config{
Certificates: []tls.Certificate{cert},
ClientCAs: caCertPool,
ClientAuth: clientAuthType,
}, nil
}