forked from kubernetes/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 1
/
authorization.go
172 lines (143 loc) · 6.02 KB
/
authorization.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
/*
Copyright 2016 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 options
import (
"fmt"
"time"
"github.com/golang/glog"
"github.com/spf13/pflag"
"k8s.io/apiserver/pkg/authorization/authorizer"
"k8s.io/apiserver/pkg/authorization/authorizerfactory"
"k8s.io/apiserver/pkg/authorization/path"
"k8s.io/apiserver/pkg/authorization/union"
"k8s.io/apiserver/pkg/server"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
"k8s.io/client-go/tools/clientcmd"
)
// DelegatingAuthorizationOptions provides an easy way for composing API servers to delegate their authorization to
// the root kube API server.
// WARNING: never assume that every authenticated incoming request already does authorization.
// The aggregator in the kube API server does this today, but this behaviour is not
// guaranteed in the future.
type DelegatingAuthorizationOptions struct {
// RemoteKubeConfigFile is the file to use to connect to a "normal" kube API server which hosts the
// SubjectAccessReview.authorization.k8s.io endpoint for checking tokens.
RemoteKubeConfigFile string
// RemoteKubeConfigFileOptional is specifying whether not specifying the kubeconfig or
// a missing in-cluster config will be fatal.
RemoteKubeConfigFileOptional bool
// AllowCacheTTL is the length of time that a successful authorization response will be cached
AllowCacheTTL time.Duration
// DenyCacheTTL is the length of time that an unsuccessful authorization response will be cached.
// You generally want more responsive, "deny, try again" flows.
DenyCacheTTL time.Duration
// AlwaysAllowPaths are HTTP paths which are excluded from authorization. They can be plain
// paths or end in * in which case prefix-match is applied. A leading / is optional.
AlwaysAllowPaths []string
}
func NewDelegatingAuthorizationOptions() *DelegatingAuthorizationOptions {
return &DelegatingAuthorizationOptions{
// very low for responsiveness, but high enough to handle storms
AllowCacheTTL: 10 * time.Second,
DenyCacheTTL: 10 * time.Second,
}
}
func (s *DelegatingAuthorizationOptions) Validate() []error {
allErrors := []error{}
return allErrors
}
func (s *DelegatingAuthorizationOptions) AddFlags(fs *pflag.FlagSet) {
if s == nil {
return
}
var optionalKubeConfigSentence string
if s.RemoteKubeConfigFileOptional {
optionalKubeConfigSentence = " This is optional. If empty, all requests not skipped by authorization are forbidden."
}
fs.StringVar(&s.RemoteKubeConfigFile, "authorization-kubeconfig", s.RemoteKubeConfigFile,
"kubeconfig file pointing at the 'core' kubernetes server with enough rights to create "+
"subjectaccessreviews.authorization.k8s.io."+optionalKubeConfigSentence)
fs.DurationVar(&s.AllowCacheTTL, "authorization-webhook-cache-authorized-ttl",
s.AllowCacheTTL,
"The duration to cache 'authorized' responses from the webhook authorizer.")
fs.DurationVar(&s.DenyCacheTTL,
"authorization-webhook-cache-unauthorized-ttl", s.DenyCacheTTL,
"The duration to cache 'unauthorized' responses from the webhook authorizer.")
fs.StringSliceVar(&s.AlwaysAllowPaths, "authorization-always-allow-paths", s.AlwaysAllowPaths,
"A list of HTTP paths to skip during authorization, i.e. these are authorized without "+
"contacting the 'core' kubernetes server.")
}
func (s *DelegatingAuthorizationOptions) ApplyTo(c *server.AuthorizationInfo) error {
if s == nil {
c.Authorizer = authorizerfactory.NewAlwaysAllowAuthorizer()
return nil
}
client, err := s.getClient()
if err != nil {
return err
}
c.Authorizer, err = s.toAuthorizer(client)
return err
}
func (s *DelegatingAuthorizationOptions) toAuthorizer(client kubernetes.Interface) (authorizer.Authorizer, error) {
var authorizers []authorizer.Authorizer
if len(s.AlwaysAllowPaths) > 0 {
a, err := path.NewAuthorizer(s.AlwaysAllowPaths)
if err != nil {
return nil, err
}
authorizers = append(authorizers, a)
}
if client == nil {
glog.Warningf("No authorization-kubeconfig provided, so SubjectAccessReview of authorization tokens won't work.")
} else {
cfg := authorizerfactory.DelegatingAuthorizerConfig{
SubjectAccessReviewClient: client.AuthorizationV1beta1().SubjectAccessReviews(),
AllowCacheTTL: s.AllowCacheTTL,
DenyCacheTTL: s.DenyCacheTTL,
}
delegatedAuthorizer, err := cfg.New()
if err != nil {
return nil, err
}
authorizers = append(authorizers, delegatedAuthorizer)
}
return union.New(authorizers...), nil
}
func (s *DelegatingAuthorizationOptions) getClient() (kubernetes.Interface, error) {
var clientConfig *rest.Config
var err error
if len(s.RemoteKubeConfigFile) > 0 {
loadingRules := &clientcmd.ClientConfigLoadingRules{ExplicitPath: s.RemoteKubeConfigFile}
loader := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{})
clientConfig, err = loader.ClientConfig()
} else {
// without the remote kubeconfig file, try to use the in-cluster config. Most addon API servers will
// use this path. If it is optional, ignore errors.
clientConfig, err = rest.InClusterConfig()
if err != nil && s.RemoteKubeConfigFileOptional {
if err != rest.ErrNotInCluster {
glog.Warningf("failed to read in-cluster kubeconfig for delegated authorization: %v", err)
}
return nil, nil
}
}
if err != nil {
return nil, fmt.Errorf("failed to get delegated authorization kubeconfig: %v", err)
}
// set high qps/burst limits since this will effectively limit API server responsiveness
clientConfig.QPS = 200
clientConfig.Burst = 400
return kubernetes.NewForConfig(clientConfig)
}