-
Notifications
You must be signed in to change notification settings - Fork 4.3k
/
matchers.go
426 lines (391 loc) · 15.4 KB
/
matchers.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
/*
* Copyright 2021 gRPC 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 rbac
import (
"errors"
"fmt"
"net"
"regexp"
v3corepb "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
v3rbacpb "github.com/envoyproxy/go-control-plane/envoy/config/rbac/v3"
v3route_componentspb "github.com/envoyproxy/go-control-plane/envoy/config/route/v3"
v3matcherpb "github.com/envoyproxy/go-control-plane/envoy/type/matcher/v3"
internalmatcher "google.golang.org/grpc/internal/xds/matcher"
)
// matcher is an interface that takes data about incoming RPC's and returns
// whether it matches with whatever matcher implements this interface.
type matcher interface {
match(data *rpcData) bool
}
// policyMatcher helps determine whether an incoming RPC call matches a policy.
// A policy is a logical role (e.g. Service Admin), which is comprised of
// permissions and principals. A principal is an identity (or identities) for a
// downstream subject which are assigned the policy (role), and a permission is
// an action(s) that a principal(s) can take. A policy matches if both a
// permission and a principal match, which will be determined by the child or
// permissions and principal matchers. policyMatcher implements the matcher
// interface.
type policyMatcher struct {
permissions *orMatcher
principals *orMatcher
}
func newPolicyMatcher(policy *v3rbacpb.Policy) (*policyMatcher, error) {
permissions, err := matchersFromPermissions(policy.Permissions)
if err != nil {
return nil, err
}
principals, err := matchersFromPrincipals(policy.Principals)
if err != nil {
return nil, err
}
return &policyMatcher{
permissions: &orMatcher{matchers: permissions},
principals: &orMatcher{matchers: principals},
}, nil
}
func (pm *policyMatcher) match(data *rpcData) bool {
// A policy matches if and only if at least one of its permissions match the
// action taking place AND at least one if its principals match the
// downstream peer.
return pm.permissions.match(data) && pm.principals.match(data)
}
// matchersFromPermissions takes a list of permissions (can also be
// a single permission, e.g. from a not matcher which is logically !permission)
// and returns a list of matchers which correspond to that permission. This will
// be called in many instances throughout the initial construction of the RBAC
// engine from the AND and OR matchers and also from the NOT matcher.
func matchersFromPermissions(permissions []*v3rbacpb.Permission) ([]matcher, error) {
var matchers []matcher
for _, permission := range permissions {
switch permission.GetRule().(type) {
case *v3rbacpb.Permission_AndRules:
mList, err := matchersFromPermissions(permission.GetAndRules().Rules)
if err != nil {
return nil, err
}
matchers = append(matchers, &andMatcher{matchers: mList})
case *v3rbacpb.Permission_OrRules:
mList, err := matchersFromPermissions(permission.GetOrRules().Rules)
if err != nil {
return nil, err
}
matchers = append(matchers, &orMatcher{matchers: mList})
case *v3rbacpb.Permission_Any:
matchers = append(matchers, &alwaysMatcher{})
case *v3rbacpb.Permission_Header:
m, err := newHeaderMatcher(permission.GetHeader())
if err != nil {
return nil, err
}
matchers = append(matchers, m)
case *v3rbacpb.Permission_UrlPath:
m, err := newURLPathMatcher(permission.GetUrlPath())
if err != nil {
return nil, err
}
matchers = append(matchers, m)
case *v3rbacpb.Permission_DestinationIp:
// Due to this being on server side, the destination IP is the local
// IP.
m, err := newLocalIPMatcher(permission.GetDestinationIp())
if err != nil {
return nil, err
}
matchers = append(matchers, m)
case *v3rbacpb.Permission_DestinationPort:
matchers = append(matchers, newPortMatcher(permission.GetDestinationPort()))
case *v3rbacpb.Permission_NotRule:
mList, err := matchersFromPermissions([]*v3rbacpb.Permission{{Rule: permission.GetNotRule().Rule}})
if err != nil {
return nil, err
}
matchers = append(matchers, ¬Matcher{matcherToNot: mList[0]})
case *v3rbacpb.Permission_Metadata:
// Never matches - so no-op if not inverted, always match if
// inverted.
if permission.GetMetadata().GetInvert() { // Test metadata being no-op and also metadata with invert always matching
matchers = append(matchers, &alwaysMatcher{})
}
case *v3rbacpb.Permission_RequestedServerName:
// Not supported in gRPC RBAC currently - a permission typed as
// requested server name in the initial config will be a no-op.
}
}
return matchers, nil
}
func matchersFromPrincipals(principals []*v3rbacpb.Principal) ([]matcher, error) {
var matchers []matcher
for _, principal := range principals {
switch principal.GetIdentifier().(type) {
case *v3rbacpb.Principal_AndIds:
mList, err := matchersFromPrincipals(principal.GetAndIds().Ids)
if err != nil {
return nil, err
}
matchers = append(matchers, &andMatcher{matchers: mList})
case *v3rbacpb.Principal_OrIds:
mList, err := matchersFromPrincipals(principal.GetOrIds().Ids)
if err != nil {
return nil, err
}
matchers = append(matchers, &orMatcher{matchers: mList})
case *v3rbacpb.Principal_Any:
matchers = append(matchers, &alwaysMatcher{})
case *v3rbacpb.Principal_Authenticated_:
authenticatedMatcher, err := newAuthenticatedMatcher(principal.GetAuthenticated())
if err != nil {
return nil, err
}
matchers = append(matchers, authenticatedMatcher)
case *v3rbacpb.Principal_DirectRemoteIp:
m, err := newRemoteIPMatcher(principal.GetDirectRemoteIp())
if err != nil {
return nil, err
}
matchers = append(matchers, m)
case *v3rbacpb.Principal_Header:
// Do we need an error here?
m, err := newHeaderMatcher(principal.GetHeader())
if err != nil {
return nil, err
}
matchers = append(matchers, m)
case *v3rbacpb.Principal_UrlPath:
m, err := newURLPathMatcher(principal.GetUrlPath())
if err != nil {
return nil, err
}
matchers = append(matchers, m)
case *v3rbacpb.Principal_NotId:
mList, err := matchersFromPrincipals([]*v3rbacpb.Principal{{Identifier: principal.GetNotId().Identifier}})
if err != nil {
return nil, err
}
matchers = append(matchers, ¬Matcher{matcherToNot: mList[0]})
case *v3rbacpb.Principal_SourceIp:
// The source ip principal identifier is deprecated. Thus, a
// principal typed as a source ip in the identifier will be a no-op.
// The config should use DirectRemoteIp instead.
case *v3rbacpb.Principal_RemoteIp:
// RBAC in gRPC treats direct_remote_ip and remote_ip as logically
// equivalent, as per A41.
m, err := newRemoteIPMatcher(principal.GetRemoteIp())
if err != nil {
return nil, err
}
matchers = append(matchers, m)
case *v3rbacpb.Principal_Metadata:
// Not supported in gRPC RBAC currently - a principal typed as
// Metadata in the initial config will be a no-op.
}
}
return matchers, nil
}
// orMatcher is a matcher where it successfully matches if one of it's
// children successfully match. It also logically represents a principal or
// permission, but can also be it's own entity further down the tree of
// matchers. orMatcher implements the matcher interface.
type orMatcher struct {
matchers []matcher
}
func (om *orMatcher) match(data *rpcData) bool {
// Range through child matchers and pass in data about incoming RPC, and
// only one child matcher has to match to be logically successful.
for _, m := range om.matchers {
if m.match(data) {
return true
}
}
return false
}
// andMatcher is a matcher that is successful if every child matcher
// matches. andMatcher implements the matcher interface.
type andMatcher struct {
matchers []matcher
}
func (am *andMatcher) match(data *rpcData) bool {
for _, m := range am.matchers {
if !m.match(data) {
return false
}
}
return true
}
// alwaysMatcher is a matcher that will always match. This logically
// represents an any rule for a permission or a principal. alwaysMatcher
// implements the matcher interface.
type alwaysMatcher struct {
}
func (am *alwaysMatcher) match(data *rpcData) bool {
return true
}
// notMatcher is a matcher that nots an underlying matcher. notMatcher
// implements the matcher interface.
type notMatcher struct {
matcherToNot matcher
}
func (nm *notMatcher) match(data *rpcData) bool {
return !nm.matcherToNot.match(data)
}
// headerMatcher is a matcher that matches on incoming HTTP Headers present
// in the incoming RPC. headerMatcher implements the matcher interface.
type headerMatcher struct {
matcher internalmatcher.HeaderMatcher
}
func newHeaderMatcher(headerMatcherConfig *v3route_componentspb.HeaderMatcher) (*headerMatcher, error) {
var m internalmatcher.HeaderMatcher
switch headerMatcherConfig.HeaderMatchSpecifier.(type) {
case *v3route_componentspb.HeaderMatcher_ExactMatch:
m = internalmatcher.NewHeaderExactMatcher(headerMatcherConfig.Name, headerMatcherConfig.GetExactMatch(), headerMatcherConfig.InvertMatch)
case *v3route_componentspb.HeaderMatcher_SafeRegexMatch:
regex, err := regexp.Compile(headerMatcherConfig.GetSafeRegexMatch().Regex)
if err != nil {
return nil, err
}
m = internalmatcher.NewHeaderRegexMatcher(headerMatcherConfig.Name, regex, headerMatcherConfig.InvertMatch)
case *v3route_componentspb.HeaderMatcher_RangeMatch:
m = internalmatcher.NewHeaderRangeMatcher(headerMatcherConfig.Name, headerMatcherConfig.GetRangeMatch().Start, headerMatcherConfig.GetRangeMatch().End, headerMatcherConfig.InvertMatch)
case *v3route_componentspb.HeaderMatcher_PresentMatch:
m = internalmatcher.NewHeaderPresentMatcher(headerMatcherConfig.Name, headerMatcherConfig.GetPresentMatch(), headerMatcherConfig.InvertMatch)
case *v3route_componentspb.HeaderMatcher_PrefixMatch:
m = internalmatcher.NewHeaderPrefixMatcher(headerMatcherConfig.Name, headerMatcherConfig.GetPrefixMatch(), headerMatcherConfig.InvertMatch)
case *v3route_componentspb.HeaderMatcher_SuffixMatch:
m = internalmatcher.NewHeaderSuffixMatcher(headerMatcherConfig.Name, headerMatcherConfig.GetSuffixMatch(), headerMatcherConfig.InvertMatch)
case *v3route_componentspb.HeaderMatcher_ContainsMatch:
m = internalmatcher.NewHeaderContainsMatcher(headerMatcherConfig.Name, headerMatcherConfig.GetContainsMatch(), headerMatcherConfig.InvertMatch)
default:
return nil, errors.New("unknown header matcher type")
}
return &headerMatcher{matcher: m}, nil
}
func (hm *headerMatcher) match(data *rpcData) bool {
return hm.matcher.Match(data.md)
}
// urlPathMatcher matches on the URL Path of the incoming RPC. In gRPC, this
// logically maps to the full method name the RPC is calling on the server side.
// urlPathMatcher implements the matcher interface.
type urlPathMatcher struct {
stringMatcher internalmatcher.StringMatcher
}
func newURLPathMatcher(pathMatcher *v3matcherpb.PathMatcher) (*urlPathMatcher, error) {
stringMatcher, err := internalmatcher.StringMatcherFromProto(pathMatcher.GetPath())
if err != nil {
return nil, err
}
return &urlPathMatcher{stringMatcher: stringMatcher}, nil
}
func (upm *urlPathMatcher) match(data *rpcData) bool {
return upm.stringMatcher.Match(data.fullMethod)
}
// remoteIPMatcher and localIPMatcher both are matchers that match against
// a CIDR Range. Two different matchers are needed as the remote and destination
// ip addresses come from different parts of the data about incoming RPC's
// passed in. Matching a CIDR Range means to determine whether the IP Address
// falls within the CIDR Range or not. They both implement the matcher
// interface.
type remoteIPMatcher struct {
// ipNet represents the CidrRange that this matcher was configured with.
// This is what will remote and destination IP's will be matched against.
ipNet *net.IPNet
}
func newRemoteIPMatcher(cidrRange *v3corepb.CidrRange) (*remoteIPMatcher, error) {
// Convert configuration to a cidrRangeString, as Go standard library has
// methods that parse cidr string.
cidrRangeString := fmt.Sprintf("%s/%d", cidrRange.AddressPrefix, cidrRange.PrefixLen.Value)
_, ipNet, err := net.ParseCIDR(cidrRangeString)
if err != nil {
return nil, err
}
return &remoteIPMatcher{ipNet: ipNet}, nil
}
func (sim *remoteIPMatcher) match(data *rpcData) bool {
return sim.ipNet.Contains(net.IP(net.ParseIP(data.peerInfo.Addr.String())))
}
type localIPMatcher struct {
ipNet *net.IPNet
}
func newLocalIPMatcher(cidrRange *v3corepb.CidrRange) (*localIPMatcher, error) {
cidrRangeString := fmt.Sprintf("%s/%d", cidrRange.AddressPrefix, cidrRange.PrefixLen.Value)
_, ipNet, err := net.ParseCIDR(cidrRangeString)
if err != nil {
return nil, err
}
return &localIPMatcher{ipNet: ipNet}, nil
}
func (dim *localIPMatcher) match(data *rpcData) bool {
return dim.ipNet.Contains(net.IP(net.ParseIP(data.localAddr.String())))
}
// portMatcher matches on whether the destination port of the RPC matches the
// destination port this matcher was instantiated with. portMatcher
// implements the matcher interface.
type portMatcher struct {
destinationPort uint32
}
func newPortMatcher(destinationPort uint32) *portMatcher {
return &portMatcher{destinationPort: destinationPort}
}
func (pm *portMatcher) match(data *rpcData) bool {
return data.destinationPort == pm.destinationPort
}
// authenticatedMatcher matches on the name of the Principal. If set, the URI
// SAN or DNS SAN in that order is used from the certificate, otherwise the
// subject field is used. If unset, it applies to any user that is
// authenticated. authenticatedMatcher implements the matcher interface.
type authenticatedMatcher struct {
stringMatcher *internalmatcher.StringMatcher
}
func newAuthenticatedMatcher(authenticatedMatcherConfig *v3rbacpb.Principal_Authenticated) (*authenticatedMatcher, error) {
// Represents this line in the RBAC documentation = "If unset, it applies to
// any user that is authenticated" (see package-level comments).
if authenticatedMatcherConfig.PrincipalName == nil {
return &authenticatedMatcher{}, nil
}
stringMatcher, err := internalmatcher.StringMatcherFromProto(authenticatedMatcherConfig.PrincipalName)
if err != nil {
return nil, err
}
return &authenticatedMatcher{stringMatcher: &stringMatcher}, nil
}
func (am *authenticatedMatcher) match(data *rpcData) bool {
if data.authType != "tls" {
// Connection is not authenticated.
return false
}
if am.stringMatcher == nil {
// Allows any authenticated user.
return true
}
// "If there is no client certificate (thus no SAN nor Subject), check if ""
// (empty string) matches. If it matches, the principal_name is said to
// match" - A41
if len(data.certs) == 0 {
return am.stringMatcher.Match("")
}
cert := data.certs[0]
// The order of matching as per the RBAC documentation (see package-level comments)
// is as follows: URI SANs, DNS SANs, and then subject name.
for _, uriSAN := range cert.URIs {
if am.stringMatcher.Match(uriSAN.String()) {
return true
}
}
for _, dnsSAN := range cert.DNSNames {
if am.stringMatcher.Match(dnsSAN) {
return true
}
}
return am.stringMatcher.Match(cert.Subject.String())
}