001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019 package org.apache.shiro.authz.permission;
020
021 import org.apache.shiro.authz.Permission;
022 import org.apache.shiro.util.CollectionUtils;
023
024 import java.io.Serializable;
025 import java.util.ArrayList;
026 import java.util.LinkedHashSet;
027 import java.util.List;
028 import java.util.Set;
029
030 /**
031 * A <code>WildcardPermission</code> is a very flexible permission construct supporting multiple levels of
032 * permission matching. However, most people will probably follow some standard conventions as explained below.
033 * <p/>
034 * <h3>Simple Usage</h3>
035 * <p/>
036 * In the simplest form, <code>WildcardPermission</code> can be used as a simple permission string. You could grant a
037 * user an "editNewsletter" permission and then check to see if the user has the editNewsletter
038 * permission by calling
039 * <p/>
040 * <code>subject.isPermitted("editNewsletter")</code>
041 * <p/>
042 * This is (mostly) equivalent to
043 * <p/>
044 * <code>subject.isPermitted( new WildcardPermission("editNewsletter") )</code>
045 * <p/>
046 * but more on that later.
047 * <p/>
048 * The simple permission string may work for simple applications, but it requires you to have permissions like
049 * <code>"viewNewsletter"</code>, <code>"deleteNewsletter"</code>,
050 * <code>"createNewsletter"</code>, etc. You can also grant a user <code>"*"</code> permissions
051 * using the wildcard character (giving this class its name), which means they have <em>all</em> permissions. But
052 * using this approach there's no way to just say a user has "all newsletter permissions".
053 * <p/>
054 * For this reason, <code>WildcardPermission</code> supports multiple <em>levels</em> of permissioning.
055 * <p/>
056 * <h3>Multiple Levels</h3>
057 * <p/>
058 * WildcardPermission</code> also supports the concept of multiple <em>levels</em>. For example, you could
059 * restructure the previous simple example by granting a user the permission <code>"newsletter:edit"</code>.
060 * The colon in this example is a special character used by the <code>WildcardPermission</code> that delimits the
061 * next token in the permission.
062 * <p/>
063 * In this example, the first token is the <em>domain</em> that is being operated on
064 * and the second token is the <em>action</em> being performed. Each level can contain multiple values. So you
065 * could simply grant a user the permission <code>"newsletter:view,edit,create"</code> which gives them
066 * access to perform <code>view</code>, <code>edit</code>, and <code>create</code> actions in the <code>newsletter</code>
067 * <em>domain</em>. Then you could check to see if the user has the <code>"newsletter:create"</code>
068 * permission by calling
069 * <p/>
070 * <code>subject.isPermitted("newsletter:create")</code>
071 * <p/>
072 * (which would return true).
073 * <p/>
074 * In addition to granting multiple permissions via a single string, you can grant all permission for a particular
075 * level. So if you wanted to grant a user all actions in the <code>newsletter</code> domain, you could simply give
076 * them <code>"newsletter:*"</code>. Now, any permission check for <code>"newsletter:XXX"</code>
077 * will return <code>true</code>. It is also possible to use the wildcard token at the domain level (or both): so you
078 * could grant a user the <code>"view"</code> action across all domains <code>"*:view"</code>.
079 * <p/>
080 * <h3>Instance-level Access Control</h3>
081 * <p/>
082 * Another common usage of the <code>WildcardPermission</code> is to model instance-level Access Control Lists.
083 * In this scenario you use three tokens - the first is the <em>domain</em>, the second is the <em>action</em>, and
084 * the third is the <em>instance</em> you are acting on.
085 * <p/>
086 * So for example you could grant a user <code>"newsletter:edit:12,13,18"</code>. In this example, assume
087 * that the third token is the system's ID of the newsletter. That would allow the user to edit newsletters
088 * <code>12</code>, <code>13</code>, and <code>18</code>. This is an extremely powerful way to express permissions,
089 * since you can now say things like <code>"newsletter:*:13"</code> (grant a user all actions for newsletter
090 * <code>13</code>), <code>"newsletter:view,create,edit:*"</code> (allow the user to
091 * <code>view</code>, <code>create</code>, or <code>edit</code> <em>any</em> newsletter), or
092 * <code>"newsletter:*:*</code> (allow the user to perform <em>any</em> action on <em>any</em> newsletter).
093 * <p/>
094 * To perform checks against these instance-level permissions, the application should include the instance ID in the
095 * permission check like so:
096 * <p/>
097 * <code>subject.isPermitted( "newsletter:edit:13" )</code>
098 * <p/>
099 * There is no limit to the number of tokens that can be used, so it is up to your imagination in terms of ways that
100 * this could be used in your application. However, the Shiro team likes to standardize some common usages shown
101 * above to help people get started and provide consistency in the Shiro community.
102 *
103 * @since 0.9
104 */
105 public class WildcardPermission implements Permission, Serializable {
106
107 //TODO - JavaDoc methods
108
109 /*--------------------------------------------
110 | C O N S T A N T S |
111 ============================================*/
112 protected static final String WILDCARD_TOKEN = "*";
113 protected static final String PART_DIVIDER_TOKEN = ":";
114 protected static final String SUBPART_DIVIDER_TOKEN = ",";
115 protected static final boolean DEFAULT_CASE_SENSITIVE = false;
116
117 /*--------------------------------------------
118 | I N S T A N C E V A R I A B L E S |
119 ============================================*/
120 private List<Set<String>> parts;
121
122 /*--------------------------------------------
123 | C O N S T R U C T O R S |
124 ============================================*/
125 /**
126 * Default no-arg constructor for subclasses only - end-user developers instantiating Permission instances must
127 * provide a wildcard string at a minimum, since Permission instances are immutable once instantiated.
128 * <p/>
129 * Note that the WildcardPermission class is very robust and typically subclasses are not necessary unless you
130 * wish to create type-safe Permission objects that would be used in your application, such as perhaps a
131 * {@code UserPermission}, {@code SystemPermission}, {@code PrinterPermission}, etc. If you want such type-safe
132 * permission usage, consider subclassing the {@link DomainPermission DomainPermission} class for your needs.
133 */
134 protected WildcardPermission() {
135 }
136
137 public WildcardPermission(String wildcardString) {
138 this(wildcardString, DEFAULT_CASE_SENSITIVE);
139 }
140
141 public WildcardPermission(String wildcardString, boolean caseSensitive) {
142 setParts(wildcardString, caseSensitive);
143 }
144
145 protected void setParts(String wildcardString) {
146 setParts(wildcardString, DEFAULT_CASE_SENSITIVE);
147 }
148
149 protected void setParts(String wildcardString, boolean caseSensitive) {
150 if (wildcardString == null || wildcardString.trim().length() == 0) {
151 throw new IllegalArgumentException("Wildcard string cannot be null or empty. Make sure permission strings are properly formatted.");
152 }
153
154 wildcardString = wildcardString.trim();
155
156 List<String> parts = CollectionUtils.asList(wildcardString.split(PART_DIVIDER_TOKEN));
157
158 this.parts = new ArrayList<Set<String>>();
159 for (String part : parts) {
160 Set<String> subparts = CollectionUtils.asSet(part.split(SUBPART_DIVIDER_TOKEN));
161 if (!caseSensitive) {
162 subparts = lowercase(subparts);
163 }
164 if (subparts.isEmpty()) {
165 throw new IllegalArgumentException("Wildcard string cannot contain parts with only dividers. Make sure permission strings are properly formatted.");
166 }
167 this.parts.add(subparts);
168 }
169
170 if (this.parts.isEmpty()) {
171 throw new IllegalArgumentException("Wildcard string cannot contain only dividers. Make sure permission strings are properly formatted.");
172 }
173 }
174
175 private Set<String> lowercase(Set<String> subparts) {
176 Set<String> lowerCasedSubparts = new LinkedHashSet<String>(subparts.size());
177 for (String subpart : subparts) {
178 lowerCasedSubparts.add(subpart.toLowerCase());
179 }
180 return lowerCasedSubparts;
181 }
182
183 /*--------------------------------------------
184 | A C C E S S O R S / M O D I F I E R S |
185 ============================================*/
186 protected List<Set<String>> getParts() {
187 return this.parts;
188 }
189
190 /*--------------------------------------------
191 | M E T H O D S |
192 ============================================*/
193
194 public boolean implies(Permission p) {
195 // By default only supports comparisons with other WildcardPermissions
196 if (!(p instanceof WildcardPermission)) {
197 return false;
198 }
199
200 WildcardPermission wp = (WildcardPermission) p;
201
202 List<Set<String>> otherParts = wp.getParts();
203
204 int i = 0;
205 for (Set<String> otherPart : otherParts) {
206 // If this permission has less parts than the other permission, everything after the number of parts contained
207 // in this permission is automatically implied, so return true
208 if (getParts().size() - 1 < i) {
209 return true;
210 } else {
211 Set<String> part = getParts().get(i);
212 if (!part.contains(WILDCARD_TOKEN) && !part.containsAll(otherPart)) {
213 return false;
214 }
215 i++;
216 }
217 }
218
219 // If this permission has more parts than the other parts, only imply it if all of the other parts are wildcards
220 for (; i < getParts().size(); i++) {
221 Set<String> part = getParts().get(i);
222 if (!part.contains(WILDCARD_TOKEN)) {
223 return false;
224 }
225 }
226
227 return true;
228 }
229
230 public String toString() {
231 StringBuilder buffer = new StringBuilder();
232 for (Set<String> part : parts) {
233 if (buffer.length() > 0) {
234 buffer.append(":");
235 }
236 buffer.append(part);
237 }
238 return buffer.toString();
239 }
240
241 public boolean equals(Object o) {
242 if (o instanceof WildcardPermission) {
243 WildcardPermission wp = (WildcardPermission) o;
244 return parts.equals(wp.parts);
245 }
246 return false;
247 }
248
249 public int hashCode() {
250 return parts.hashCode();
251 }
252
253 }