-
Notifications
You must be signed in to change notification settings - Fork 402
/
dispatcher.go
466 lines (418 loc) · 18.6 KB
/
dispatcher.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
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
/*
Copyright 2018 The Kubernetes Authors.
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.
*/
// Package mutating delegates admission checks to dynamically configured
// mutating webhooks.
package mutating
import (
"context"
"fmt"
"time"
jsonpatch "github.com/evanphx/json-patch"
apiequality "k8s.io/apimachinery/pkg/api/equality"
"k8s.io/klog/v2"
admissionv1 "k8s.io/api/admission/v1"
admissionregistrationv1 "k8s.io/api/admissionregistration/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/serializer/json"
utiljson "k8s.io/apimachinery/pkg/util/json"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apiserver/pkg/admission"
admissionmetrics "k8s.io/apiserver/pkg/admission/metrics"
"k8s.io/apiserver/pkg/admission/plugin/webhook"
webhookerrors "k8s.io/apiserver/pkg/admission/plugin/webhook/errors"
"k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
webhookrequest "k8s.io/apiserver/pkg/admission/plugin/webhook/request"
auditinternal "k8s.io/apiserver/pkg/apis/audit"
endpointsrequest "k8s.io/apiserver/pkg/endpoints/request"
webhookutil "k8s.io/apiserver/pkg/util/webhook"
"k8s.io/apiserver/pkg/warning"
utiltrace "k8s.io/utils/trace"
)
const (
// PatchAuditAnnotationPrefix is a prefix for persisting webhook patch in audit annotation.
// Audit handler decides whether annotation with this prefix should be logged based on audit level.
// Since mutating webhook patches the request body, audit level must be greater or equal to Request
// for the annotation to be logged
PatchAuditAnnotationPrefix = "patch.webhook.admission.k8s.io/"
// MutationAuditAnnotationPrefix is a prefix for presisting webhook mutation existence in audit annotation.
MutationAuditAnnotationPrefix = "mutation.webhook.admission.k8s.io/"
// MutationAnnotationFailedOpenKeyPrefix in an annotation indicates
// the mutating webhook failed open when the webhook backend connection
// failed or returned an internal server error.
MutationAuditAnnotationFailedOpenKeyPrefix string = "failed-open." + MutationAuditAnnotationPrefix
)
type mutatingDispatcher struct {
cm *webhookutil.ClientManager
plugin *Plugin
}
func newMutatingDispatcher(p *Plugin) func(cm *webhookutil.ClientManager) generic.Dispatcher {
return func(cm *webhookutil.ClientManager) generic.Dispatcher {
return &mutatingDispatcher{cm, p}
}
}
var _ generic.Dispatcher = &mutatingDispatcher{}
func (a *mutatingDispatcher) Dispatch(ctx context.Context, attr admission.Attributes, o admission.ObjectInterfaces, hooks []webhook.WebhookAccessor) error {
reinvokeCtx := attr.GetReinvocationContext()
var webhookReinvokeCtx *webhookReinvokeContext
if v := reinvokeCtx.Value(PluginName); v != nil {
webhookReinvokeCtx = v.(*webhookReinvokeContext)
} else {
webhookReinvokeCtx = &webhookReinvokeContext{}
reinvokeCtx.SetValue(PluginName, webhookReinvokeCtx)
}
if reinvokeCtx.IsReinvoke() && webhookReinvokeCtx.IsOutputChangedSinceLastWebhookInvocation(attr.GetObject()) {
// If the object has changed, we know the in-tree plugin re-invocations have mutated the object,
// and we need to reinvoke all eligible webhooks.
webhookReinvokeCtx.RequireReinvokingPreviouslyInvokedPlugins()
}
defer func() {
webhookReinvokeCtx.SetLastWebhookInvocationOutput(attr.GetObject())
}()
var versionedAttr *generic.VersionedAttributes
for i, hook := range hooks {
attrForCheck := attr
if versionedAttr != nil {
attrForCheck = versionedAttr
}
invocation, statusErr := a.plugin.ShouldCallHook(hook, attrForCheck, o)
if statusErr != nil {
return statusErr
}
if invocation == nil {
continue
}
hook, ok := invocation.Webhook.GetMutatingWebhook()
if !ok {
return fmt.Errorf("mutating webhook dispatch requires v1.MutatingWebhook, but got %T", hook)
}
// This means that during reinvocation, a webhook will not be
// called for the first time. For example, if the webhook is
// skipped in the first round because of mismatching labels,
// even if the labels become matching, the webhook does not
// get called during reinvocation.
if reinvokeCtx.IsReinvoke() && !webhookReinvokeCtx.ShouldReinvokeWebhook(invocation.Webhook.GetUID()) {
continue
}
if versionedAttr == nil {
// First webhook, create versioned attributes
var err error
if versionedAttr, err = generic.NewVersionedAttributes(attr, invocation.Kind, o); err != nil {
return apierrors.NewInternalError(err)
}
} else {
// Subsequent webhook, convert existing versioned attributes to this webhook's version
if err := generic.ConvertVersionedAttributes(versionedAttr, invocation.Kind, o); err != nil {
return apierrors.NewInternalError(err)
}
}
t := time.Now()
round := 0
if reinvokeCtx.IsReinvoke() {
round = 1
}
annotator := newWebhookAnnotator(versionedAttr, round, i, hook.Name, invocation.Webhook.GetConfigurationName())
changed, err := a.callAttrMutatingHook(ctx, hook, invocation, versionedAttr, annotator, o, round, i)
ignoreClientCallFailures := hook.FailurePolicy != nil && *hook.FailurePolicy == admissionregistrationv1.Ignore
rejected := false
if err != nil {
switch err := err.(type) {
case *webhookutil.ErrCallingWebhook:
if !ignoreClientCallFailures {
rejected = true
admissionmetrics.Metrics.ObserveWebhookRejection(ctx, hook.Name, "admit", string(versionedAttr.Attributes.GetOperation()), admissionmetrics.WebhookRejectionCallingWebhookError, int(err.Status.ErrStatus.Code))
}
admissionmetrics.Metrics.ObserveWebhook(ctx, hook.Name, time.Since(t), rejected, versionedAttr.Attributes, "admit", int(err.Status.ErrStatus.Code))
case *webhookutil.ErrWebhookRejection:
rejected = true
admissionmetrics.Metrics.ObserveWebhookRejection(ctx, hook.Name, "admit", string(versionedAttr.Attributes.GetOperation()), admissionmetrics.WebhookRejectionNoError, int(err.Status.ErrStatus.Code))
admissionmetrics.Metrics.ObserveWebhook(ctx, hook.Name, time.Since(t), rejected, versionedAttr.Attributes, "admit", int(err.Status.ErrStatus.Code))
default:
rejected = true
admissionmetrics.Metrics.ObserveWebhookRejection(ctx, hook.Name, "admit", string(versionedAttr.Attributes.GetOperation()), admissionmetrics.WebhookRejectionAPIServerInternalError, 0)
admissionmetrics.Metrics.ObserveWebhook(ctx, hook.Name, time.Since(t), rejected, versionedAttr.Attributes, "admit", 0)
}
} else {
admissionmetrics.Metrics.ObserveWebhook(ctx, hook.Name, time.Since(t), rejected, versionedAttr.Attributes, "admit", 200)
}
if changed {
// Patch had changed the object. Prepare to reinvoke all previous webhooks that are eligible for re-invocation.
webhookReinvokeCtx.RequireReinvokingPreviouslyInvokedPlugins()
reinvokeCtx.SetShouldReinvoke()
}
if hook.ReinvocationPolicy != nil && *hook.ReinvocationPolicy == admissionregistrationv1.IfNeededReinvocationPolicy {
webhookReinvokeCtx.AddReinvocableWebhookToPreviouslyInvoked(invocation.Webhook.GetUID())
}
if err == nil {
continue
}
if callErr, ok := err.(*webhookutil.ErrCallingWebhook); ok {
if ignoreClientCallFailures {
klog.Warningf("Failed calling webhook, failing open %v: %v", hook.Name, callErr)
admissionmetrics.Metrics.ObserveWebhookFailOpen(ctx, hook.Name, "admit")
annotator.addFailedOpenAnnotation()
utilruntime.HandleError(callErr)
select {
case <-ctx.Done():
// parent context is canceled or timed out, no point in continuing
return apierrors.NewTimeoutError("request did not complete within requested timeout", 0)
default:
// individual webhook timed out, but parent context did not, continue
continue
}
}
klog.Warningf("Failed calling webhook, failing closed %v: %v", hook.Name, err)
return apierrors.NewInternalError(err)
}
if rejectionErr, ok := err.(*webhookutil.ErrWebhookRejection); ok {
return rejectionErr.Status
}
return err
}
// convert versionedAttr.VersionedObject to the internal version in the underlying admission.Attributes
if versionedAttr != nil && versionedAttr.VersionedObject != nil && versionedAttr.Dirty {
return o.GetObjectConvertor().Convert(versionedAttr.VersionedObject, versionedAttr.Attributes.GetObject(), nil)
}
return nil
}
// note that callAttrMutatingHook updates attr
func (a *mutatingDispatcher) callAttrMutatingHook(ctx context.Context, h *admissionregistrationv1.MutatingWebhook, invocation *generic.WebhookInvocation, attr *generic.VersionedAttributes, annotator *webhookAnnotator, o admission.ObjectInterfaces, round, idx int) (bool, error) {
configurationName := invocation.Webhook.GetConfigurationName()
changed := false
defer func() { annotator.addMutationAnnotation(changed) }()
if attr.Attributes.IsDryRun() {
if h.SideEffects == nil {
return false, &webhookutil.ErrCallingWebhook{WebhookName: h.Name, Reason: fmt.Errorf("Webhook SideEffects is nil"), Status: apierrors.NewBadRequest("Webhook SideEffects is nil")}
}
if !(*h.SideEffects == admissionregistrationv1.SideEffectClassNone || *h.SideEffects == admissionregistrationv1.SideEffectClassNoneOnDryRun) {
return false, webhookerrors.NewDryRunUnsupportedErr(h.Name)
}
}
uid, request, response, err := webhookrequest.CreateAdmissionObjects(attr, invocation)
if err != nil {
return false, &webhookutil.ErrCallingWebhook{WebhookName: h.Name, Reason: fmt.Errorf("could not create admission objects: %w", err), Status: apierrors.NewBadRequest("error creating admission objects")}
}
// Make the webhook request
client, err := invocation.Webhook.GetRESTClient(a.cm)
if err != nil {
return false, &webhookutil.ErrCallingWebhook{WebhookName: h.Name, Reason: fmt.Errorf("could not get REST client: %w", err), Status: apierrors.NewBadRequest("error getting REST client")}
}
trace := utiltrace.New("Call mutating webhook",
utiltrace.Field{"configuration", configurationName},
utiltrace.Field{"webhook", h.Name},
utiltrace.Field{"resource", attr.GetResource()},
utiltrace.Field{"subresource", attr.GetSubresource()},
utiltrace.Field{"operation", attr.GetOperation()},
utiltrace.Field{"UID", uid})
defer trace.LogIfLong(500 * time.Millisecond)
// if the webhook has a specific timeout, wrap the context to apply it
if h.TimeoutSeconds != nil {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, time.Duration(*h.TimeoutSeconds)*time.Second)
defer cancel()
}
r := client.Post().Body(request)
// if the context has a deadline, set it as a parameter to inform the backend
if deadline, hasDeadline := ctx.Deadline(); hasDeadline {
// compute the timeout
if timeout := time.Until(deadline); timeout > 0 {
// if it's not an even number of seconds, round up to the nearest second
if truncated := timeout.Truncate(time.Second); truncated != timeout {
timeout = truncated + time.Second
}
// set the timeout
r.Timeout(timeout)
}
}
do := func() { err = r.Do(ctx).Into(response) }
if wd, ok := endpointsrequest.LatencyTrackersFrom(ctx); ok {
tmp := do
do = func() { wd.MutatingWebhookTracker.Track(tmp) }
}
do()
if err != nil {
var status *apierrors.StatusError
if se, ok := err.(*apierrors.StatusError); ok {
status = se
} else {
status = apierrors.NewBadRequest("error calling webhook")
}
return false, &webhookutil.ErrCallingWebhook{WebhookName: h.Name, Reason: fmt.Errorf("failed to call webhook: %w", err), Status: status}
}
trace.Step("Request completed")
result, err := webhookrequest.VerifyAdmissionResponse(uid, true, response)
if err != nil {
return false, &webhookutil.ErrCallingWebhook{WebhookName: h.Name, Reason: fmt.Errorf("received invalid webhook response: %w", err), Status: apierrors.NewServiceUnavailable("error validating webhook response")}
}
for k, v := range result.AuditAnnotations {
key := h.Name + "/" + k
if err := attr.Attributes.AddAnnotation(key, v); err != nil {
klog.Warningf("Failed to set admission audit annotation %s to %s for mutating webhook %s: %v", key, v, h.Name, err)
}
}
for _, w := range result.Warnings {
warning.AddWarning(ctx, "", w)
}
if !result.Allowed {
return false, &webhookutil.ErrWebhookRejection{Status: webhookerrors.ToStatusErr(h.Name, result.Result)}
}
if len(result.Patch) == 0 {
return false, nil
}
patchObj, err := jsonpatch.DecodePatch(result.Patch)
if err != nil {
return false, apierrors.NewInternalError(err)
}
if len(patchObj) == 0 {
return false, nil
}
// if a non-empty patch was provided, and we have no object we can apply it to (e.g. a DELETE admission operation), error
if attr.VersionedObject == nil {
return false, apierrors.NewInternalError(fmt.Errorf("admission webhook %q attempted to modify the object, which is not supported for this operation", h.Name))
}
var patchedJS []byte
jsonSerializer := json.NewSerializer(json.DefaultMetaFactory, o.GetObjectCreater(), o.GetObjectTyper(), false)
switch result.PatchType {
// VerifyAdmissionResponse normalizes to v1 patch types, regardless of the AdmissionReview version used
case admissionv1.PatchTypeJSONPatch:
objJS, err := runtime.Encode(jsonSerializer, attr.VersionedObject)
if err != nil {
return false, apierrors.NewInternalError(err)
}
patchedJS, err = patchObj.Apply(objJS)
if err != nil {
return false, apierrors.NewInternalError(err)
}
default:
return false, &webhookutil.ErrCallingWebhook{WebhookName: h.Name, Reason: fmt.Errorf("unsupported patch type %q", result.PatchType), Status: webhookerrors.ToStatusErr(h.Name, result.Result)}
}
var newVersionedObject runtime.Object
if _, ok := attr.VersionedObject.(*unstructured.Unstructured); ok {
// Custom Resources don't have corresponding Go struct's.
// They are represented as Unstructured.
newVersionedObject = &unstructured.Unstructured{}
} else {
newVersionedObject, err = o.GetObjectCreater().New(attr.VersionedKind)
if err != nil {
return false, apierrors.NewInternalError(err)
}
}
// TODO: if we have multiple mutating webhooks, we can remember the json
// instead of encoding and decoding for each one.
if newVersionedObject, _, err = jsonSerializer.Decode(patchedJS, nil, newVersionedObject); err != nil {
return false, apierrors.NewInternalError(err)
}
changed = !apiequality.Semantic.DeepEqual(attr.VersionedObject, newVersionedObject)
trace.Step("Patch applied")
annotator.addPatchAnnotation(patchObj, result.PatchType)
attr.Dirty = true
attr.VersionedObject = newVersionedObject
o.GetObjectDefaulter().Default(attr.VersionedObject)
return changed, nil
}
type webhookAnnotator struct {
attr *generic.VersionedAttributes
failedOpenAnnotationKey string
patchAnnotationKey string
mutationAnnotationKey string
webhook string
configuration string
}
func newWebhookAnnotator(attr *generic.VersionedAttributes, round, idx int, webhook, configuration string) *webhookAnnotator {
return &webhookAnnotator{
attr: attr,
failedOpenAnnotationKey: fmt.Sprintf("%sround_%d_index_%d", MutationAuditAnnotationFailedOpenKeyPrefix, round, idx),
patchAnnotationKey: fmt.Sprintf("%sround_%d_index_%d", PatchAuditAnnotationPrefix, round, idx),
mutationAnnotationKey: fmt.Sprintf("%sround_%d_index_%d", MutationAuditAnnotationPrefix, round, idx),
webhook: webhook,
configuration: configuration,
}
}
func (w *webhookAnnotator) addFailedOpenAnnotation() {
if w.attr == nil || w.attr.Attributes == nil {
return
}
value := w.webhook
if err := w.attr.Attributes.AddAnnotation(w.failedOpenAnnotationKey, value); err != nil {
klog.Warningf("failed to set failed open annotation for mutating webhook key %s to %s: %v", w.failedOpenAnnotationKey, value, err)
}
}
func (w *webhookAnnotator) addMutationAnnotation(mutated bool) {
if w.attr == nil || w.attr.Attributes == nil {
return
}
value, err := mutationAnnotationValue(w.configuration, w.webhook, mutated)
if err != nil {
klog.Warningf("unexpected error composing mutating webhook annotation: %v", err)
return
}
if err := w.attr.Attributes.AddAnnotation(w.mutationAnnotationKey, value); err != nil {
klog.Warningf("failed to set mutation annotation for mutating webhook key %s to %s: %v", w.mutationAnnotationKey, value, err)
}
}
func (w *webhookAnnotator) addPatchAnnotation(patch interface{}, patchType admissionv1.PatchType) {
if w.attr == nil || w.attr.Attributes == nil {
return
}
var value string
var err error
switch patchType {
case admissionv1.PatchTypeJSONPatch:
value, err = jsonPatchAnnotationValue(w.configuration, w.webhook, patch)
if err != nil {
klog.Warningf("unexpected error composing mutating webhook JSON patch annotation: %v", err)
return
}
default:
klog.Warningf("unsupported patch type for mutating webhook annotation: %v", patchType)
return
}
if err := w.attr.Attributes.AddAnnotationWithLevel(w.patchAnnotationKey, value, auditinternal.LevelRequest); err != nil {
// NOTE: we don't log actual patch in kube-apiserver log to avoid potentially
// leaking information
klog.Warningf("failed to set patch annotation for mutating webhook key %s; confugiration name: %s, webhook name: %s", w.patchAnnotationKey, w.configuration, w.webhook)
}
}
// MutationAuditAnnotation logs if a webhook invocation mutated the request object
type MutationAuditAnnotation struct {
Configuration string `json:"configuration"`
Webhook string `json:"webhook"`
Mutated bool `json:"mutated"`
}
// PatchAuditAnnotation logs a patch from a mutating webhook
type PatchAuditAnnotation struct {
Configuration string `json:"configuration"`
Webhook string `json:"webhook"`
Patch interface{} `json:"patch,omitempty"`
PatchType string `json:"patchType,omitempty"`
}
func mutationAnnotationValue(configuration, webhook string, mutated bool) (string, error) {
m := MutationAuditAnnotation{
Configuration: configuration,
Webhook: webhook,
Mutated: mutated,
}
bytes, err := utiljson.Marshal(m)
return string(bytes), err
}
func jsonPatchAnnotationValue(configuration, webhook string, patch interface{}) (string, error) {
p := PatchAuditAnnotation{
Configuration: configuration,
Webhook: webhook,
Patch: patch,
PatchType: string(admissionv1.PatchTypeJSONPatch),
}
bytes, err := utiljson.Marshal(p)
return string(bytes), err
}