J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2006 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.security.provider; |
| 27 | |
| 28 | import java.security.MessageDigestSpi; |
| 29 | import java.security.DigestException; |
| 30 | import java.security.ProviderException; |
| 31 | |
| 32 | /** |
| 33 | * Common base message digest implementation for the Sun provider. |
| 34 | * It implements all the JCA methods as suitable for a Java message digest |
| 35 | * implementation of an algorithm based on a compression function (as all |
| 36 | * commonly used algorithms are). The individual digest subclasses only need to |
| 37 | * implement the following methods: |
| 38 | * |
| 39 | * . abstract void implCompress(byte[] b, int ofs); |
| 40 | * . abstract void implDigest(byte[] out, int ofs); |
| 41 | * . abstract void implReset(); |
| 42 | * . public abstract Object clone(); |
| 43 | * |
| 44 | * See the inline documentation for details. |
| 45 | * |
| 46 | * @since 1.5 |
| 47 | * @author Andreas Sterbenz |
| 48 | */ |
| 49 | abstract class DigestBase extends MessageDigestSpi implements Cloneable { |
| 50 | |
| 51 | // one element byte array, temporary storage for update(byte) |
| 52 | private byte[] oneByte; |
| 53 | |
| 54 | // algorithm name to use in the exception message |
| 55 | private final String algorithm; |
| 56 | // length of the message digest in bytes |
| 57 | private final int digestLength; |
| 58 | |
| 59 | // size of the input to the compression function in bytes |
| 60 | private final int blockSize; |
| 61 | // buffer to store partial blocks, blockSize bytes large |
| 62 | // Subclasses should not access this array directly except possibly in their |
| 63 | // implDigest() method. See MD5.java as an example. |
| 64 | final byte[] buffer; |
| 65 | // offset into buffer |
| 66 | private int bufOfs; |
| 67 | |
| 68 | // number of bytes processed so far. subclasses should not modify |
| 69 | // this value. |
| 70 | // also used as a flag to indicate reset status |
| 71 | // -1: need to call engineReset() before next call to update() |
| 72 | // 0: is already reset |
| 73 | long bytesProcessed; |
| 74 | |
| 75 | /** |
| 76 | * Main constructor. |
| 77 | */ |
| 78 | DigestBase(String algorithm, int digestLength, int blockSize) { |
| 79 | super(); |
| 80 | this.algorithm = algorithm; |
| 81 | this.digestLength = digestLength; |
| 82 | this.blockSize = blockSize; |
| 83 | buffer = new byte[blockSize]; |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * Constructor for cloning. Replicates common data. |
| 88 | */ |
| 89 | DigestBase(DigestBase base) { |
| 90 | this.algorithm = base.algorithm; |
| 91 | this.digestLength = base.digestLength; |
| 92 | this.blockSize = base.blockSize; |
| 93 | this.buffer = base.buffer.clone(); |
| 94 | this.bufOfs = base.bufOfs; |
| 95 | this.bytesProcessed = base.bytesProcessed; |
| 96 | } |
| 97 | |
| 98 | // return digest length. See JCA doc. |
| 99 | protected final int engineGetDigestLength() { |
| 100 | return digestLength; |
| 101 | } |
| 102 | |
| 103 | // single byte update. See JCA doc. |
| 104 | protected final void engineUpdate(byte b) { |
| 105 | if (oneByte == null) { |
| 106 | oneByte = new byte[1]; |
| 107 | } |
| 108 | oneByte[0] = b; |
| 109 | engineUpdate(oneByte, 0, 1); |
| 110 | } |
| 111 | |
| 112 | // array update. See JCA doc. |
| 113 | protected final void engineUpdate(byte[] b, int ofs, int len) { |
| 114 | if (len == 0) { |
| 115 | return; |
| 116 | } |
| 117 | if ((ofs < 0) || (len < 0) || (ofs > b.length - len)) { |
| 118 | throw new ArrayIndexOutOfBoundsException(); |
| 119 | } |
| 120 | if (bytesProcessed < 0) { |
| 121 | engineReset(); |
| 122 | } |
| 123 | bytesProcessed += len; |
| 124 | // if buffer is not empty, we need to fill it before proceeding |
| 125 | if (bufOfs != 0) { |
| 126 | int n = Math.min(len, blockSize - bufOfs); |
| 127 | System.arraycopy(b, ofs, buffer, bufOfs, n); |
| 128 | bufOfs += n; |
| 129 | ofs += n; |
| 130 | len -= n; |
| 131 | if (bufOfs >= blockSize) { |
| 132 | // compress completed block now |
| 133 | implCompress(buffer, 0); |
| 134 | bufOfs = 0; |
| 135 | } |
| 136 | } |
| 137 | // compress complete blocks |
| 138 | while (len >= blockSize) { |
| 139 | implCompress(b, ofs); |
| 140 | len -= blockSize; |
| 141 | ofs += blockSize; |
| 142 | } |
| 143 | // copy remainder to buffer |
| 144 | if (len > 0) { |
| 145 | System.arraycopy(b, ofs, buffer, 0, len); |
| 146 | bufOfs = len; |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | // reset this object. See JCA doc. |
| 151 | protected final void engineReset() { |
| 152 | if (bytesProcessed == 0) { |
| 153 | // already reset, ignore |
| 154 | return; |
| 155 | } |
| 156 | implReset(); |
| 157 | bufOfs = 0; |
| 158 | bytesProcessed = 0; |
| 159 | } |
| 160 | |
| 161 | // return the digest. See JCA doc. |
| 162 | protected final byte[] engineDigest() { |
| 163 | byte[] b = new byte[digestLength]; |
| 164 | try { |
| 165 | engineDigest(b, 0, b.length); |
| 166 | } catch (DigestException e) { |
| 167 | throw (ProviderException) |
| 168 | new ProviderException("Internal error").initCause(e); |
| 169 | } |
| 170 | return b; |
| 171 | } |
| 172 | |
| 173 | // return the digest in the specified array. See JCA doc. |
| 174 | protected final int engineDigest(byte[] out, int ofs, int len) |
| 175 | throws DigestException { |
| 176 | if (len < digestLength) { |
| 177 | throw new DigestException("Length must be at least " |
| 178 | + digestLength + " for " + algorithm + "digests"); |
| 179 | } |
| 180 | if ((ofs < 0) || (len < 0) || (ofs > out.length - len)) { |
| 181 | throw new DigestException("Buffer too short to store digest"); |
| 182 | } |
| 183 | if (bytesProcessed < 0) { |
| 184 | engineReset(); |
| 185 | } |
| 186 | implDigest(out, ofs); |
| 187 | bytesProcessed = -1; |
| 188 | return digestLength; |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * Core compression function. Processes blockSize bytes at a time |
| 193 | * and updates the state of this object. |
| 194 | */ |
| 195 | abstract void implCompress(byte[] b, int ofs); |
| 196 | |
| 197 | /** |
| 198 | * Return the digest. Subclasses do not need to reset() themselves, |
| 199 | * DigestBase calls implReset() when necessary. |
| 200 | */ |
| 201 | abstract void implDigest(byte[] out, int ofs); |
| 202 | |
| 203 | /** |
| 204 | * Reset subclass specific state to their initial values. DigestBase |
| 205 | * calls this method when necessary. |
| 206 | */ |
| 207 | abstract void implReset(); |
| 208 | |
| 209 | /** |
| 210 | * Clone this digest. Should be implemented as "return new MyDigest(this)". |
| 211 | * That constructor should first call "super(baseDigest)" and then copy |
| 212 | * subclass specific data. |
| 213 | */ |
| 214 | public abstract Object clone(); |
| 215 | |
| 216 | // padding used for the MD5, and SHA-* message digests |
| 217 | static final byte[] padding; |
| 218 | |
| 219 | static { |
| 220 | // we need 128 byte padding for SHA-384/512 |
| 221 | // and an additional 8 bytes for the high 8 bytes of the 16 |
| 222 | // byte bit counter in SHA-384/512 |
| 223 | padding = new byte[136]; |
| 224 | padding[0] = (byte)0x80; |
| 225 | } |
| 226 | |
| 227 | } |