1 /*
2 * Copyright (c) 1997, 2023, 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 sun.security.util.Debug;
29
30 import java.util.Map;
31 import java.util.Objects;
32 import java.util.concurrent.ConcurrentHashMap;
33 import java.util.function.Function;
34
35 /**
36 * This class extends {@code 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 * @since 1.2
43 */
44 public class SecureClassLoader extends ClassLoader {
45
46 /*
47 * Map that maps the CodeSource to a ProtectionDomain. The key is a
48 * CodeSourceKey class that uses a {@code String} instead of a URL to avoid
49 * potential expensive name service lookups. This does mean that URLs that
50 * are equivalent after nameservice lookup will be placed in separate
51 * ProtectionDomains; however during policy enforcement these URLs will be
52 * canonicalized and resolved resulting in a consistent set of granted
53 * permissions.
54 */
55 private final Map<CodeSourceKey, ProtectionDomain> pdcache
56 = new ConcurrentHashMap<>(11);
57
58 static {
59 ClassLoader.registerAsParallelCapable();
60 }
61
62 /**
63 * Creates a new {@code SecureClassLoader} using the specified parent
64 * class loader for delegation.
65 *
66 * <p>If there is a security manager, this method first
67 * calls the security manager's {@code checkCreateClassLoader}
68 * method to ensure creation of a class loader is allowed.
69 *
70 * @param parent the parent ClassLoader
71 * @throws SecurityException if a security manager exists and its
72 * {@code checkCreateClassLoader} method doesn't allow
73 * creation of a class loader.
74 * @see SecurityManager#checkCreateClassLoader
75 */
76 protected SecureClassLoader(ClassLoader parent) {
77 super(parent);
78 }
79
80 /**
81 * Creates a new {@code SecureClassLoader} using the default parent class
82 * loader for delegation.
83 *
84 * <p>If there is a security manager, this method first
85 * calls the security manager's {@code checkCreateClassLoader}
86 * method to ensure creation of a class loader is allowed.
87 *
88 * @throws SecurityException if a security manager exists and its
89 * {@code checkCreateClassLoader} method doesn't allow
90 * creation of a class loader.
91 * @see SecurityManager#checkCreateClassLoader
92 */
93 protected SecureClassLoader() {
94 super();
95 }
96
97 /**
98 * Creates a new {@code SecureClassLoader} of the specified name and
99 * using the specified parent class loader for delegation.
100 *
101 * @param name class loader name; or {@code null} if not named
102 * @param parent the parent class loader
103 *
104 * @throws IllegalArgumentException if the given name is empty.
105 *
106 * @throws SecurityException if a security manager exists and its
107 * {@link SecurityManager#checkCreateClassLoader()} method
108 * doesn't allow creation of a class loader.
109 *
110 * @since 9
111 */
112 protected SecureClassLoader(String name, ClassLoader parent) {
113 super(name, parent);
114 }
115
116 /**
117 * Converts an array of bytes into an instance of class {@code Class},
118 * with an optional CodeSource. Before the
119 * class can be used it must be resolved.
120 * <p>
121 * If a non-null CodeSource is supplied a ProtectionDomain is
122 * constructed and associated with the class being defined.
123 *
124 * @param name the expected name of the class, or {@code null}
125 * if not known, using '.' and not '/' as the separator
126 * and without a trailing ".class" suffix.
127 * @param b the bytes that make up the class data. The bytes in
128 * positions {@code off} through {@code off+len-1}
129 * should have the format of a valid class file as defined by
130 * <cite>The Java Virtual Machine Specification</cite>.
131 * @param off the start offset in {@code b} of the class data
132 * @param len the length of the class data
133 * @param cs the associated CodeSource, or {@code null} if none
134 * @return the {@code Class} object created from the data,
135 * and optional CodeSource.
136 * @throws ClassFormatError if the data did not contain a valid class
137 * @throws IndexOutOfBoundsException if either {@code off} or
138 * {@code len} is negative, or if
139 * {@code off+len} is greater than {@code b.length}.
140 *
141 * @throws SecurityException if an attempt is made to add this class
142 * to a package that contains classes that were signed by
143 * a different set of certificates than this class, or if
144 * the class name begins with "java.".
145 */
146 protected final Class<?> defineClass(String name,
147 byte[] b, int off, int len,
148 CodeSource cs)
149 {
150 return defineClass(name, b, off, len, getProtectionDomain(cs));
151 }
152
153 /**
154 * Converts a {@link java.nio.ByteBuffer ByteBuffer}
155 * into an instance of class {@code Class}, with an optional CodeSource.
156 * Before the class can be used it must be resolved.
157 * <p>
158 * If a non-null CodeSource is supplied a ProtectionDomain is
159 * constructed and associated with the class being defined.
160 *
161 * @param name the expected name of the class, or {@code null}
162 * if not known, using '.' and not '/' as the separator
163 * and without a trailing ".class" suffix.
164 * @param b the bytes that make up the class data. The bytes from positions
165 * {@code b.position()} through {@code b.position() + b.limit() -1}
166 * should have the format of a valid class file as defined by
167 * <cite>The Java Virtual Machine Specification</cite>.
168 * @param cs the associated CodeSource, or {@code null} if none
169 * @return the {@code Class} object created from the data,
170 * and optional CodeSource.
171 * @throws ClassFormatError if the data did not contain a valid class
172 * @throws SecurityException if an attempt is made to add this class
173 * to a package that contains classes that were signed by
174 * a different set of certificates than this class, or if
175 * the class name begins with "java.".
176 *
177 * @since 1.5
178 */
179 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
180 CodeSource cs)
181 {
182 return defineClass(name, b, getProtectionDomain(cs));
183 }
184
185 /**
186 * Returns the permissions for the given CodeSource object.
187 * <p>
188 * This method is invoked by the defineClass method which takes
189 * a CodeSource as an argument when it is constructing the
190 * ProtectionDomain for the class being defined.
191 *
192 * @param codesource the codesource.
193 *
194 * @return the permissions granted to the codesource.
195 *
196 */
197 protected PermissionCollection getPermissions(CodeSource codesource)
198 {
199 return new Permissions(); // ProtectionDomain defers the binding
200 }
201
202 /*
203 * holder class for the static field "debug" to delay its initialization
204 */
205 private static class DebugHolder {
206 private static final Debug debug = Debug.getInstance("scl");
207 }
208
209 /*
210 * Returned cached ProtectionDomain for the specified CodeSource.
211 */
212 private ProtectionDomain getProtectionDomain(CodeSource cs) {
213 if (cs == null) {
214 return null;
215 }
216
217 // Use a CodeSourceKey object key. It should behave in the
218 // same manner as the CodeSource when compared for equality except
219 // that no nameservice lookup is done on the hostname (String comparison
220 // only), and the fragment is not considered.
221 CodeSourceKey key = new CodeSourceKey(cs);
222 return pdcache.computeIfAbsent(key, new Function<>() {
223 // Do not turn this into a lambda since it is executed during bootstrap
224 @Override
225 public ProtectionDomain apply(CodeSourceKey key) {
226 PermissionCollection perms
227 = SecureClassLoader.this.getPermissions(key.cs);
228 ProtectionDomain pd = new ProtectionDomain(
229 key.cs, perms, SecureClassLoader.this, null);
230 if (DebugHolder.debug != null) {
231 DebugHolder.debug.println(" getPermissions " + pd);
232 DebugHolder.debug.println("");
233 }
234 return pd;
235 }
236 });
237 }
238
239 private record CodeSourceKey(CodeSource cs) {
240
241 @Override
242 public int hashCode() {
243 return Objects.hashCode(cs.getLocationNoFragString());
244 }
245
246 @Override
247 public boolean equals(Object obj) {
248 if (obj == this) {
249 return true;
250 }
251
252 return obj instanceof CodeSourceKey other
253 && Objects.equals(cs.getLocationNoFragString(),
254 other.cs.getLocationNoFragString())
255 && cs.matchCerts(other.cs, true);
256 }
257 }
258
259 /**
260 * Called by the VM, during -Xshare:dump
261 */
262 private void resetArchivedStates() {
263 pdcache.clear();
264 }
265 }