1 /*
2 * Copyright (c) 1997, 2011, 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.HashMap;
29 import java.util.ArrayList;
30 import java.net.URL;
31
32 import sun.security.util.Debug;
33
34 /**
35 * This class extends ClassLoader with additional support for defining
36 * classes with an associated code source and permissions which are
37 * retrieved by the system policy by default.
38 *
39 * @author Li Gong
40 * @author Roland Schemers
41 */
42 public class SecureClassLoader extends ClassLoader {
43 /*
44 * If initialization succeed this is set to true and security checks will
45 * succeed. Otherwise the object is not initialized and the object is
46 * useless.
47 */
48 private final boolean initialized;
49
50 // HashMap that maps CodeSource to ProtectionDomain
51 // @GuardedBy("pdcache")
52 private final HashMap<CodeSource, ProtectionDomain> pdcache =
53 new HashMap<>(11);
54
55 private static final Debug debug = Debug.getInstance("scl");
56
57 static {
58 ClassLoader.registerAsParallelCapable();
59 }
60
61 /**
62 * Creates a new SecureClassLoader using the specified parent
63 * class loader for delegation.
64 *
65 * <p>If there is a security manager, this method first
66 * calls the security manager's <code>checkCreateClassLoader</code>
67 * method to ensure creation of a class loader is allowed.
68 * <p>
69 * @param parent the parent ClassLoader
70 * @exception SecurityException if a security manager exists and its
71 * <code>checkCreateClassLoader</code> method doesn't allow
72 * creation of a class loader.
73 * @see SecurityManager#checkCreateClassLoader
74 */
75 protected SecureClassLoader(ClassLoader parent) {
76 super(parent);
77 // this is to make the stack depth consistent with 1.1
78 SecurityManager security = System.getSecurityManager();
79 if (security != null) {
80 security.checkCreateClassLoader();
81 }
82 initialized = true;
83 }
84
85 /**
86 * Creates a new SecureClassLoader using the default parent class
87 * loader for delegation.
88 *
89 * <p>If there is a security manager, this method first
90 * calls the security manager's <code>checkCreateClassLoader</code>
91 * method to ensure creation of a class loader is allowed.
92 *
93 * @exception SecurityException if a security manager exists and its
94 * <code>checkCreateClassLoader</code> method doesn't allow
95 * creation of a class loader.
96 * @see SecurityManager#checkCreateClassLoader
97 */
98 protected SecureClassLoader() {
99 super();
100 // this is to make the stack depth consistent with 1.1
101 SecurityManager security = System.getSecurityManager();
102 if (security != null) {
103 security.checkCreateClassLoader();
104 }
105 initialized = true;
106 }
107
108 /**
109 * Converts an array of bytes into an instance of class Class,
110 * with an optional CodeSource. Before the
111 * class can be used it must be resolved.
112 * <p>
113 * If a non-null CodeSource is supplied a ProtectionDomain is
114 * constructed and associated with the class being defined.
115 * <p>
116 * @param name the expected name of the class, or <code>null</code>
117 * if not known, using '.' and not '/' as the separator
118 * and without a trailing ".class" suffix.
119 * @param b the bytes that make up the class data. The bytes in
120 * positions <code>off</code> through <code>off+len-1</code>
121 * should have the format of a valid class file as defined by
122 * <cite>The Java™ Virtual Machine Specification</cite>.
123 * @param off the start offset in <code>b</code> of the class data
124 * @param len the length of the class data
125 * @param cs the associated CodeSource, or <code>null</code> if none
126 * @return the <code>Class</code> object created from the data,
127 * and optional CodeSource.
128 * @exception ClassFormatError if the data did not contain a valid class
129 * @exception IndexOutOfBoundsException if either <code>off</code> or
130 * <code>len</code> is negative, or if
131 * <code>off+len</code> is greater than <code>b.length</code>.
132 *
133 * @exception SecurityException if an attempt is made to add this class
134 * to a package that contains classes that were signed by
135 * a different set of certificates than this class, or if
136 * the class name begins with "java.".
137 */
138 protected final Class<?> defineClass(String name,
139 byte[] b, int off, int len,
140 CodeSource cs)
141 {
142 return defineClass(name, b, off, len, getProtectionDomain(cs));
143 }
144
145 /**
146 * Converts a {@link java.nio.ByteBuffer <tt>ByteBuffer</tt>}
147 * into an instance of class <tt>Class</tt>, with an optional CodeSource.
148 * Before the class can be used it must be resolved.
149 * <p>
150 * If a non-null CodeSource is supplied a ProtectionDomain is
151 * constructed and associated with the class being defined.
152 * <p>
153 * @param name the expected name of the class, or <code>null</code>
154 * if not known, using '.' and not '/' as the separator
155 * and without a trailing ".class" suffix.
156 * @param b the bytes that make up the class data. The bytes from positions
157 * <tt>b.position()</tt> through <tt>b.position() + b.limit() -1</tt>
158 * should have the format of a valid class file as defined by
159 * <cite>The Java™ Virtual Machine Specification</cite>.
160 * @param cs the associated CodeSource, or <code>null</code> if none
161 * @return the <code>Class</code> object created from the data,
162 * and optional CodeSource.
163 * @exception ClassFormatError if the data did not contain a valid class
164 * @exception SecurityException if an attempt is made to add this class
165 * to a package that contains classes that were signed by
166 * a different set of certificates than this class, or if
167 * the class name begins with "java.".
168 *
169 * @since 1.5
170 */
171 protected final Class<?> defineClass(String name, java.nio.ByteBuffer b,
172 CodeSource cs)
173 {
174 return defineClass(name, b, getProtectionDomain(cs));
175 }
176
177 /**
178 * Returns the permissions for the given CodeSource object.
179 * <p>
180 * This method is invoked by the defineClass method which takes
181 * a CodeSource as an argument when it is constructing the
182 * ProtectionDomain for the class being defined.
183 * <p>
184 * @param codesource the codesource.
185 *
186 * @return the permissions granted to the codesource.
187 *
188 */
189 protected PermissionCollection getPermissions(CodeSource codesource)
190 {
191 check();
192 return new Permissions(); // ProtectionDomain defers the binding
193 }
194
195 /*
196 * Returned cached ProtectionDomain for the specified CodeSource.
197 */
198 private ProtectionDomain getProtectionDomain(CodeSource cs) {
199 if (cs == null)
200 return null;
201
202 ProtectionDomain pd = null;
203 synchronized (pdcache) {
204 pd = pdcache.get(cs);
205 if (pd == null) {
206 PermissionCollection perms = getPermissions(cs);
207 pd = new ProtectionDomain(cs, perms, this, null);
208 pdcache.put(cs, pd);
209 if (debug != null) {
210 debug.println(" getPermissions "+ pd);
211 debug.println("");
212 }
213 }
214 }
215 return pd;
216 }
217
218 /*
219 * Check to make sure the class loader has been initialized.
220 */
221 private void check() {
222 if (!initialized) {
223 throw new SecurityException("ClassLoader object not initialized");
224 }
225 }
226
227 }
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