1/* 2 * Copyright (c) 1997, 2013, 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 26package java.security; 27 28import java.util.HashMap; 29import java.util.ArrayList; 30import java.net.URL; 31 32import 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 */ 42public 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} 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} 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} 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} 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} 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} through {@code off+len-1} 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} of the class data 124 * @param len the length of the class data 125 * @param cs the associated CodeSource, or {@code null} if none 126 * @return the {@code Class} 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} or 130 * {@code len} is negative, or if 131 * {@code off+len} is greater than {@code b.length}. 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 ByteBuffer} 147 * into an instance of class {@code Class}, 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} 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 * {@code b.position()} through {@code b.position() + b.limit() -1} 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} if none 161 * @return the {@code Class} 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} 228