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1: /* SecureRandomAdapter.java -- 2: Copyright (C) 2001, 2002, 2003, 2006 Free Software Foundation, Inc. 3: 4: This file is a part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2 of the License, or (at 9: your option) any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; if not, write to the Free Software 18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 19: USA 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package gnu.java.security.jce.prng; 40: 41: import gnu.java.security.action.GetSecurityPropertyAction; 42: import gnu.classpath.SystemProperties; 43: import gnu.java.security.prng.LimitReachedException; 44: import gnu.java.security.prng.MDGenerator; 45: 46: import java.security.AccessController; 47: import java.security.SecureRandom; 48: import java.security.SecureRandomSpi; 49: 50: import java.util.Collections; 51: import java.util.logging.Level; 52: import java.util.logging.Logger; 53: 54: import java.io.InputStream; 55: import java.io.IOException; 56: 57: import java.net.MalformedURLException; 58: import java.net.URL; 59: 60: /** 61: * <p>The implementation of a generic {@link java.security.SecureRandom} adapter 62: * class to wrap gnu.crypto prng instances based on Message Digest algorithms.</p> 63: * 64: * <p>This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) for 65: * the {@link java.security.SecureRandom} class, which provides the 66: * functionality of a cryptographically strong pseudo-random number generator.</p> 67: * 68: * <p>All the abstract methods in the {@link SecureRandomSpi} class are 69: * implemented by this class and all its sub-classes.</p> 70: */ 71: public abstract class SecureRandomAdapter 72: extends SecureRandomSpi 73: { 74: 75: private boolean isSeeded = false; 76: 77: /** Our underlying prng instance. */ 78: private MDGenerator adaptee = new MDGenerator(); 79: 80: /** The name of the message digest algorithm used by the adaptee. */ 81: private String mdName; 82: 83: private static final Logger logger = 84: Logger.getLogger(SecureRandom.class.getName()); 85: 86: private static final String SECURERANDOM_SOURCE = "securerandom.source"; 87: private static final String JAVA_SECURITY_EGD = "java.security.egd"; 88: 89: /** 90: * <p>Trivial protected constructor.</p> 91: * 92: * @param mdName the canonical name of the underlying hash algorithm. 93: */ 94: protected SecureRandomAdapter(String mdName) 95: { 96: super(); 97: 98: this.mdName = mdName; 99: adaptee.init (Collections.singletonMap (MDGenerator.MD_NAME, mdName)); 100: } 101: 102: public static final byte[] getSeed(int numBytes) 103: { 104: URL sourceUrl = null; 105: String urlStr = null; 106: 107: byte[] buffer = new byte[numBytes]; 108: 109: GetSecurityPropertyAction action = 110: new GetSecurityPropertyAction(SECURERANDOM_SOURCE); 111: try 112: { 113: urlStr = (String) AccessController.doPrivileged(action); 114: if (urlStr != null) 115: sourceUrl = new URL(urlStr); 116: } 117: catch (MalformedURLException ignored) 118: { 119: logger.log(Level.WARNING, 120: SECURERANDOM_SOURCE + " property is malformed: {0}", 121: urlStr); 122: } 123: 124: if (sourceUrl == null) 125: { 126: try 127: { 128: urlStr = SystemProperties.getProperty(JAVA_SECURITY_EGD); 129: if (urlStr != null) 130: sourceUrl = new URL(urlStr); 131: } 132: catch (MalformedURLException mue) 133: { 134: logger.log(Level.WARNING, 135: JAVA_SECURITY_EGD + " property is malformed: {0}", 136: urlStr); 137: } 138: } 139: 140: if (sourceUrl != null) 141: { 142: try 143: { 144: InputStream in = sourceUrl.openStream(); 145: in.read(buffer); 146: return buffer; 147: } 148: catch (IOException ioe) 149: { 150: logger.log(Level.FINE, "error reading random bytes", ioe); 151: } 152: } 153: 154: // If we get here, we did not get any seed from a property URL. 155: VMSecureRandom.generateSeed(buffer, 0, buffer.length); 156: return buffer; 157: } 158: 159: public byte[] engineGenerateSeed(int numBytes) 160: { 161: return getSeed(numBytes); 162: } 163: 164: public void engineNextBytes(byte[] bytes) 165: { 166: if (!isSeeded) 167: { 168: engineSetSeed(engineGenerateSeed(32)); 169: } 170: try 171: { 172: adaptee.nextBytes(bytes, 0, bytes.length); 173: } 174: catch (LimitReachedException ignored) 175: { 176: } 177: } 178: 179: public void engineSetSeed(byte[] seed) 180: { 181: adaptee.addRandomBytes (seed); 182: isSeeded = true; 183: } 184: }