forked from minio/minio
/
bucket-policy-handlers.go
302 lines (278 loc) · 8.95 KB
/
bucket-policy-handlers.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
/*
* Minio Cloud Storage, (C) 2015, 2016 Minio, Inc.
*
* 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 main
import (
"bytes"
"io"
"io/ioutil"
"net/http"
"strings"
mux "github.com/gorilla/mux"
)
// maximum supported access policy size.
const maxAccessPolicySize = 20 * 1024 // 20KiB.
// Verify if a given action is valid for the url path based on the
// existing bucket access policy.
func bucketPolicyEvalStatements(action string, resource string, conditions map[string]string, statements []policyStatement) bool {
for _, statement := range statements {
if bucketPolicyMatchStatement(action, resource, conditions, statement) {
if statement.Effect == "Allow" {
return true
}
// Do not uncomment kept here for readability.
// else statement.Effect == "Deny"
return false
}
}
// None match so deny.
return false
}
// Verify if action, resource and conditions match input policy statement.
func bucketPolicyMatchStatement(action string, resource string, conditions map[string]string, statement policyStatement) bool {
// Verify if action matches.
if bucketPolicyActionMatch(action, statement) {
// Verify if resource matches.
if bucketPolicyResourceMatch(resource, statement) {
// Verify if condition matches.
if bucketPolicyConditionMatch(conditions, statement) {
return true
}
}
}
return false
}
// Verify if given action matches with policy statement.
func bucketPolicyActionMatch(action string, statement policyStatement) bool {
for _, policyAction := range statement.Actions {
if matched := actionMatch(policyAction, action); matched {
return true
}
}
return false
}
// Match function matches wild cards in 'pattern' for 'text'.
func wildCardMatch(pattern, text string) bool {
if pattern == "" {
return text == pattern
}
if pattern == "*" {
return true
}
parts := strings.Split(pattern, "*")
if len(parts) == 1 {
return text == pattern
}
tGlob := strings.HasSuffix(pattern, "*")
end := len(parts) - 1
if !strings.HasPrefix(text, parts[0]) {
return false
}
for i := 1; i < end; i++ {
if !strings.Contains(text, parts[i]) {
return false
}
idx := strings.Index(text, parts[i]) + len(parts[i])
text = text[idx:]
}
return tGlob || strings.HasSuffix(text, parts[end])
}
// Match function matches wild cards in 'pattern' for resource.
func resourceMatch(pattern, resource string) bool {
return wildCardMatch(pattern, resource)
}
// Match function matches wild cards in 'pattern' for action.
func actionMatch(pattern, action string) bool {
return wildCardMatch(pattern, action)
}
// Verify if given resource matches with policy statement.
func bucketPolicyResourceMatch(resource string, statement policyStatement) bool {
for _, resourcep := range statement.Resources {
// the resource rule for object could contain "*" wild card.
// the requested object can be given access based on the already set bucket policy if
// the match is successful.
// More info: http://docs.aws.amazon.com/AmazonS3/latest/dev/s3-arn-format.html .
if matched := resourceMatch(resourcep, resource); matched {
return true
}
}
return false
}
// Verify if given condition matches with policy statement.
func bucketPolicyConditionMatch(conditions map[string]string, statement policyStatement) bool {
// Supports following conditions.
// - StringEquals
// - StringNotEquals
//
// Supported applicable condition keys for each conditions.
// - s3:prefix
// - s3:max-keys
var conditionMatches = true
for condition, conditionKeys := range statement.Conditions {
if condition == "StringEquals" {
if conditionKeys["s3:prefix"] != conditions["prefix"] {
conditionMatches = false
break
}
if conditionKeys["s3:max-keys"] != conditions["max-keys"] {
conditionMatches = false
break
}
} else if condition == "StringNotEquals" {
if conditionKeys["s3:prefix"] == conditions["prefix"] {
conditionMatches = false
break
}
if conditionKeys["s3:max-keys"] == conditions["max-keys"] {
conditionMatches = false
break
}
}
}
return conditionMatches
}
// PutBucketPolicyHandler - PUT Bucket policy
// -----------------
// This implementation of the PUT operation uses the policy
// subresource to add to or replace a policy on a bucket
func (api objectAPIHandlers) PutBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
bucket := vars["bucket"]
switch getRequestAuthType(r) {
default:
// For all unknown auth types return error.
writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
return
case authTypePresigned, authTypeSigned:
if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
}
// If Content-Length is unknown or zero, deny the
// request. PutBucketPolicy always needs a Content-Length if
// incoming request is not chunked.
if !contains(r.TransferEncoding, "chunked") {
if r.ContentLength == -1 || r.ContentLength == 0 {
writeErrorResponse(w, r, ErrMissingContentLength, r.URL.Path)
return
}
// If Content-Length is greater than maximum allowed policy size.
if r.ContentLength > maxAccessPolicySize {
writeErrorResponse(w, r, ErrEntityTooLarge, r.URL.Path)
return
}
}
// Read access policy up to maxAccessPolicySize.
// http://docs.aws.amazon.com/AmazonS3/latest/dev/access-policy-language-overview.html
// bucket policies are limited to 20KB in size, using a limit reader.
bucketPolicyBuf, err := ioutil.ReadAll(io.LimitReader(r.Body, maxAccessPolicySize))
if err != nil {
errorIf(err, "Unable to read bucket policy.")
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
return
}
// Parse bucket policy.
bucketPolicy, err := parseBucketPolicy(bucketPolicyBuf)
if err != nil {
errorIf(err, "Unable to parse bucket policy.")
writeErrorResponse(w, r, ErrInvalidPolicyDocument, r.URL.Path)
return
}
// Parse check bucket policy.
if s3Error := checkBucketPolicyResources(bucket, bucketPolicy); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
// Save bucket policy.
if err := writeBucketPolicy(bucket, bucketPolicyBuf); err != nil {
errorIf(err, "Unable to write bucket policy.")
switch err.(type) {
case BucketNameInvalid:
writeErrorResponse(w, r, ErrInvalidBucketName, r.URL.Path)
default:
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
}
return
}
writeSuccessNoContent(w)
}
// DeleteBucketPolicyHandler - DELETE Bucket policy
// -----------------
// This implementation of the DELETE operation uses the policy
// subresource to add to remove a policy on a bucket.
func (api objectAPIHandlers) DeleteBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
bucket := vars["bucket"]
switch getRequestAuthType(r) {
default:
// For all unknown auth types return error.
writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
return
case authTypePresigned, authTypeSigned:
if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
}
// Delete bucket access policy.
if err := removeBucketPolicy(bucket); err != nil {
errorIf(err, "Unable to remove bucket policy.")
switch err.(type) {
case BucketNameInvalid:
writeErrorResponse(w, r, ErrInvalidBucketName, r.URL.Path)
case BucketPolicyNotFound:
writeErrorResponse(w, r, ErrNoSuchBucketPolicy, r.URL.Path)
default:
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
}
return
}
writeSuccessNoContent(w)
}
// GetBucketPolicyHandler - GET Bucket policy
// -----------------
// This operation uses the policy
// subresource to return the policy of a specified bucket.
func (api objectAPIHandlers) GetBucketPolicyHandler(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
bucket := vars["bucket"]
switch getRequestAuthType(r) {
default:
// For all unknown auth types return error.
writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
return
case authTypePresigned, authTypeSigned:
if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
}
// Read bucket access policy.
p, err := readBucketPolicy(bucket)
if err != nil {
errorIf(err, "Unable to read bucket policy.")
switch err.(type) {
case BucketNameInvalid:
writeErrorResponse(w, r, ErrInvalidBucketName, r.URL.Path)
case BucketPolicyNotFound:
writeErrorResponse(w, r, ErrNoSuchBucketPolicy, r.URL.Path)
default:
writeErrorResponse(w, r, ErrInternalError, r.URL.Path)
}
return
}
io.Copy(w, bytes.NewReader(p))
}