1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.security;
27
28 import java.util.Map;
29 import java.util.Objects;
30 import java.util.concurrent.ConcurrentHashMap;
31 import java.util.function.Function;
32
33 import sun.security.util.Debug;
34
35 /**
36 * This class extends ClassLoader with additional support for defining
37 * classes with an associated code source and permissions which are
38 * retrieved by the system policy by default.
39 *
40 * @author Li Gong
41 * @author Roland Schemers
42 */
43 public class SecureClassLoader extends ClassLoader {
44 /*
45 * If initialization succeed this is set to true and security checks will
46 * succeed. Otherwise the object is not initialized and the object is
47 * useless.
48 */
49 private final boolean initialized;
50
51 /*
52 * Map that maps the CodeSource to a ProtectionDomain. The key is a
53 * CodeSourceKey class that uses a String instead of a URL to avoid
54 * potential expensive name service lookups. This does mean that URLs that
55 * are equivalent after nameservice lookup will be placed in separate
56 * ProtectionDomains; however during policy enforcement these URLs will be
57 * canonicalized and resolved resulting in a consistent set of granted
58 * permissions.
59 */
60 private final Map<CodeSourceKey, ProtectionDomain> pdcache
61 = new ConcurrentHashMap<>(11);
62
63 static {
64 ClassLoader.registerAsParallelCapable();
65 }
66
67 /**
68 * Creates a new SecureClassLoader using the specified parent
69 * class loader for delegation.
70 *
71 * <p>If there is a security manager, this method first
72 * calls the security manager's {@code checkCreateClassLoader}
73 * method to ensure creation of a class loader is allowed.
74 *
75 * @param parent the parent ClassLoader
76 * @exception SecurityException if a security manager exists and its
77 * {@code checkCreateClassLoader} method doesn't allow
78 * creation of a class loader.
79 * @see SecurityManager#checkCreateClassLoader
80 */
81 protected SecureClassLoader(ClassLoader parent) {
82 super(parent);
83 // this is to make the stack depth consistent with 1.1
84 SecurityManager security = System.getSecurityManager();
85 if (security != null) {
86 security.checkCreateClassLoader();
87 }
88 initialized = true;
89 }
90
91 /**
92 * Creates a new SecureClassLoader using the default parent class
93 * loader for delegation.
94 *
95 * <p>If there is a security manager, this method first
96 * calls the security manager's {@code checkCreateClassLoader}
97 * method to ensure creation of a class loader is allowed.
98 *
99 * @exception SecurityException if a security manager exists and its
100 * {@code checkCreateClassLoader} method doesn't allow
101 * creation of a class loader.
102 * @see SecurityManager#checkCreateClassLoader
103 */
104 protected SecureClassLoader() {
105 super();
106 // this is to make the stack depth consistent with 1.1
107 SecurityManager security = System.getSecurityManager();
108 if (security != null) {
109 security.checkCreateClassLoader();
110 }
111 initialized = true;
112 }
113
114 /**
115 * Creates a new {@code SecureClassLoader} of the specified name and
116 * using the specified parent class loader for delegation.
117 *
118 * @param name class loader name; or {@code null} if not named
119 * @param parent the parent class loader
120 *
121 * @throws SecurityException if a security manager exists and its
122 * {@link SecurityManager#checkCreateClassLoader()} method
123 * doesn't allow creation of a class loader.
124 *
125 * @since 9
126 */
127 protected SecureClassLoader(String name, ClassLoader parent) {
128 super(name, parent);
129 SecurityManager security = System.getSecurityManager();
130 if (security != null) {
131 security.checkCreateClassLoader();
132 }
133 initialized = true;
134 }
135
136 /**
137 * Converts an array of bytes into an instance of class Class,
138 * with an optional CodeSource. Before the
139 * class can be used it must be resolved.
140 * <p>
141 * If a non-null CodeSource is supplied a ProtectionDomain is
142 * constructed and associated with the class being defined.
143 *
144 * @param name the expected name of the class, or {@code null}
145 * if not known, using '.' and not '/' as the separator
146 * and without a trailing ".class" suffix.
147 * @param b the bytes that make up the class data. The bytes in
148 * positions {@code off} through {@code off+len-1}
149 * should have the format of a valid class file as defined by
150 * <cite>The Java™ Virtual Machine Specification</cite>.
151 * @param off the start offset in {@code b} of the class data
152 * @param len the length of the class data
153 * @param cs the associated CodeSource, or {@code null} if none
154 * @return the {@code Class} object created from the data,
155 * and optional CodeSource.
156 * @exception ClassFormatError if the data did not contain a valid class
157 * @exception IndexOutOfBoundsException if either {@code off} or
158 * {@code len} is negative, or if
159 * {@code off+len} is greater than {@code b.length}.
160 *
161 * @exception SecurityException if an attempt is made to add this class
162 * to a package that contains classes that were signed by
163 * a different set of certificates than this class, or if
164 * the class name begins with "java.".
165 */
166 protected final Class<?> defineClass(String name,
167 byte[] b, int off, int len,
168 CodeSource cs)
169 {
170 return defineClass(name, b, off, len, getProtectionDomain(cs));
171 }
172
173 /**
174 * Converts a {@link java.nio.ByteBuffer ByteBuffer}
175 * into an instance of class {@code Class}, with an optional CodeSource.
176 * Before the class can be used it must be resolved.
177 * <p>
178 * If a non-null CodeSource is supplied a ProtectionDomain is
179 * constructed and associated with the class being defined.
180 *
181 * @param name the expected name of the class, or {@code null}
182 * if not known, using '.' and not '/' as the separator
183 * and without a trailing ".class" suffix.
184 * @param b the bytes that make up the class data. The bytes from positions
185 * {@code b.position()} through {@code b.position() + b.limit() -1}
186 * should have the format of a valid class file as defined by
187 * <cite>The Java™ Virtual Machine Specification</cite>.
188 * @param cs the associated CodeSource, or {@code null} if none
189 * @return the {@code Class} object created from the data,
190 * and optional CodeSource.
191 * @exception ClassFormatError if the data did not contain a valid class
192 * @exception SecurityException if an attempt is made to add this class
193 * to a package that contains classes that were signed by
194 * a different set of certificates than this class, or if
195 * the class name begins with "java.".
196 *
197 * @since 1.5
198 */
199 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
200 CodeSource cs)
201 {
202 return defineClass(name, b, getProtectionDomain(cs));
203 }
204
205 /**
206 * Returns the permissions for the given CodeSource object.
207 * <p>
208 * This method is invoked by the defineClass method which takes
209 * a CodeSource as an argument when it is constructing the
210 * ProtectionDomain for the class being defined.
211 *
212 * @param codesource the codesource.
213 *
214 * @return the permissions granted to the codesource.
215 *
216 */
217 protected PermissionCollection getPermissions(CodeSource codesource)
218 {
219 check();
220 return new Permissions(); // ProtectionDomain defers the binding
221 }
222
223 /*
224 * holder class for the static field "debug" to delay its initialization
225 */
226 private static class DebugHolder {
227 private static final Debug debug = Debug.getInstance("scl");
228 }
229
230 /*
231 * Returned cached ProtectionDomain for the specified CodeSource.
232 */
233 private ProtectionDomain getProtectionDomain(CodeSource cs) {
234 if (cs == null) {
235 return null;
236 }
237
238 // Use a CodeSourceKey object key. It should behave in the
239 // same manner as the CodeSource when compared for equality except
240 // that no nameservice lookup is done on the hostname (String comparison
241 // only), and the fragment is not considered.
242 CodeSourceKey key = new CodeSourceKey(cs);
243 return pdcache.computeIfAbsent(key, new Function<>() {
244 @Override
245 public ProtectionDomain apply(CodeSourceKey key /* not used */) {
246 PermissionCollection perms
247 = SecureClassLoader.this.getPermissions(cs);
248 ProtectionDomain pd = new ProtectionDomain(
249 cs, perms, SecureClassLoader.this, null);
250 if (DebugHolder.debug != null) {
251 DebugHolder.debug.println(" getPermissions " + pd);
252 DebugHolder.debug.println("");
253 }
254 return pd;
255 }
256 });
257 }
258
259 /*
260 * Check to make sure the class loader has been initialized.
261 */
262 private void check() {
263 if (!initialized) {
264 throw new SecurityException("ClassLoader object not initialized");
265 }
266 }
267
268 private static class CodeSourceKey {
269 private final CodeSource cs;
270
271 CodeSourceKey(CodeSource cs) {
272 this.cs = cs;
273 }
274
275 @Override
276 public int hashCode() {
277 String locationNoFrag = cs.getLocationNoFragString();
278 return locationNoFrag != null ? locationNoFrag.hashCode() : 0;
279 }
280
281 @Override
282 public boolean equals(Object obj) {
283 if (obj == this) {
284 return true;
285 }
286
287 if (!(obj instanceof CodeSourceKey)) {
288 return false;
289 }
290
291 CodeSourceKey csk = (CodeSourceKey) obj;
292
293 if (!Objects.equals(cs.getLocationNoFragString(),
294 csk.cs.getLocationNoFragString())) {
295 return false;
296 }
297
298 return cs.matchCerts(csk.cs, true);
299 }
300 }
301 }