Showing the changes to java/pkg/javax/crypto/CipherInputStream.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,322 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (c) 1997, 2007, 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 javax.crypto; | ||
| 27 | |||
| 28 | import java.io.*; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * A CipherInputStream is composed of an InputStream and a Cipher so | ||
| 32 | * that read() methods return data that are read in from the | ||
| 33 | * underlying InputStream but have been additionally processed by the | ||
| 34 | * Cipher. The Cipher must be fully initialized before being used by | ||
| 35 | * a CipherInputStream. | ||
| 36 | * | ||
| 37 | * <p> For example, if the Cipher is initialized for decryption, the | ||
| 38 | * CipherInputStream will attempt to read in data and decrypt them, | ||
| 39 | * before returning the decrypted data. | ||
| 40 | * | ||
| 41 | * <p> This class adheres strictly to the semantics, especially the | ||
| 42 | * failure semantics, of its ancestor classes | ||
| 43 | * java.io.FilterInputStream and java.io.InputStream. This class has | ||
| 44 | * exactly those methods specified in its ancestor classes, and | ||
| 45 | * overrides them all. Moreover, this class catches all exceptions | ||
| 46 | * that are not thrown by its ancestor classes. In particular, the | ||
| 47 | * <code>skip</code> method skips, and the <code>available</code> | ||
| 48 | * method counts only data that have been processed by the encapsulated Cipher. | ||
| 49 | * | ||
| 50 | * <p> It is crucial for a programmer using this class not to use | ||
| 51 | * methods that are not defined or overriden in this class (such as a | ||
| 52 | * new method or constructor that is later added to one of the super | ||
| 53 | * classes), because the design and implementation of those methods | ||
| 54 | * are unlikely to have considered security impact with regard to | ||
| 55 | * CipherInputStream. | ||
| 56 | * | ||
| 57 | * @author Li Gong | ||
| 58 | * @see java.io.InputStream | ||
| 59 | * @see java.io.FilterInputStream | ||
| 60 | * @see javax.crypto.Cipher | ||
| 61 | * @see javax.crypto.CipherOutputStream | ||
| 62 | * | ||
| 63 | * @since 1.4 | ||
| 64 | */ | ||
| 65 | |||
| 66 | public class CipherInputStream extends FilterInputStream { | ||
| 67 | |||
| 68 | // the cipher engine to use to process stream data | ||
| 69 | private Cipher cipher; | ||
| 70 | |||
| 71 | // the underlying input stream | ||
| 72 | private InputStream input; | ||
| 73 | |||
| 74 | /* the buffer holding data that have been read in from the | ||
| 75 | underlying stream, but have not been processed by the cipher | ||
| 76 | engine. the size 512 bytes is somewhat randomly chosen */ | ||
| 77 | private byte[] ibuffer = new byte[512]; | ||
| 78 | |||
| 79 | // having reached the end of the underlying input stream | ||
| 80 | private boolean done = false; | ||
| 81 | |||
| 82 | /* the buffer holding data that have been processed by the cipher | ||
| 83 | engine, but have not been read out */ | ||
| 84 | private byte[] obuffer; | ||
| 85 | // the offset pointing to the next "new" byte | ||
| 86 | private int ostart = 0; | ||
| 87 | // the offset pointing to the last "new" byte | ||
| 88 | private int ofinish = 0; | ||
| 89 | |||
| 90 | /** | ||
| 91 | * private convenience function. | ||
| 92 | * | ||
| 93 | * Entry condition: ostart = ofinish | ||
| 94 | * | ||
| 95 | * Exit condition: ostart <= ofinish | ||
| 96 | * | ||
| 97 | * return (ofinish-ostart) (we have this many bytes for you) | ||
| 98 | * return 0 (no data now, but could have more later) | ||
| 99 | * return -1 (absolutely no more data) | ||
| 100 | */ | ||
| 101 | private int getMoreData() throws IOException { | ||
| 102 | if (done) return -1; | ||
| 103 | int readin = input.read(ibuffer); | ||
| 104 | if (readin == -1) { | ||
| 105 | done = true; | ||
| 106 | try { | ||
| 107 | obuffer = cipher.doFinal(); | ||
| 108 | } | ||
| 109 | catch (IllegalBlockSizeException e) {obuffer = null;} | ||
| 110 | catch (BadPaddingException e) {obuffer = null;} | ||
| 111 | if (obuffer == null) | ||
| 112 | return -1; | ||
| 113 | else { | ||
| 114 | ostart = 0; | ||
| 115 | ofinish = obuffer.length; | ||
| 116 | return ofinish; | ||
| 117 | } | ||
| 118 | } | ||
| 119 | try { | ||
| 120 | obuffer = cipher.update(ibuffer, 0, readin); | ||
| 121 | } catch (IllegalStateException e) {obuffer = null;}; | ||
| 122 | ostart = 0; | ||
| 123 | if (obuffer == null) | ||
| 124 | ofinish = 0; | ||
| 125 | else ofinish = obuffer.length; | ||
| 126 | return ofinish; | ||
| 127 | } | ||
| 128 | |||
| 129 | /** | ||
| 130 | * Constructs a CipherInputStream from an InputStream and a | ||
| 131 | * Cipher. | ||
| 132 | * <br>Note: if the specified input stream or cipher is | ||
| 133 | * null, a NullPointerException may be thrown later when | ||
| 134 | * they are used. | ||
| 135 | * @param is the to-be-processed input stream | ||
| 136 | * @param c an initialized Cipher object | ||
| 137 | */ | ||
| 138 | public CipherInputStream(InputStream is, Cipher c) { | ||
| 139 | super(is); | ||
| 140 | input = is; | ||
| 141 | cipher = c; | ||
| 142 | } | ||
| 143 | |||
| 144 | /** | ||
| 145 | * Constructs a CipherInputStream from an InputStream without | ||
| 146 | * specifying a Cipher. This has the effect of constructing a | ||
| 147 | * CipherInputStream using a NullCipher. | ||
| 148 | * <br>Note: if the specified input stream is null, a | ||
| 149 | * NullPointerException may be thrown later when it is used. | ||
| 150 | * @param is the to-be-processed input stream | ||
| 151 | */ | ||
| 152 | protected CipherInputStream(InputStream is) { | ||
| 153 | super(is); | ||
| 154 | input = is; | ||
| 155 | cipher = new NullCipher(); | ||
| 156 | } | ||
| 157 | |||
| 158 | /** | ||
| 159 | * Reads the next byte of data from this input stream. The value | ||
| 160 | * byte is returned as an <code>int</code> in the range | ||
| 161 | * <code>0</code> to <code>255</code>. If no byte is available | ||
| 162 | * because the end of the stream has been reached, the value | ||
| 163 | * <code>-1</code> is returned. This method blocks until input data | ||
| 164 | * is available, the end of the stream is detected, or an exception | ||
| 165 | * is thrown. | ||
| 166 | * <p> | ||
| 167 | * | ||
| 168 | * @return the next byte of data, or <code>-1</code> if the end of the | ||
| 169 | * stream is reached. | ||
| 170 | * @exception IOException if an I/O error occurs. | ||
| 171 | * @since JCE1.2 | ||
| 172 | */ | ||
| 173 | public int read() throws IOException { | ||
| 174 | if (ostart >= ofinish) { | ||
| 175 | // we loop for new data as the spec says we are blocking | ||
| 176 | int i = 0; | ||
| 177 | while (i == 0) i = getMoreData(); | ||
| 178 | if (i == -1) return -1; | ||
| 179 | } | ||
| 180 | return ((int) obuffer[ostart++] & 0xff); | ||
| 181 | }; | ||
| 182 | |||
| 183 | /** | ||
| 184 | * Reads up to <code>b.length</code> bytes of data from this input | ||
| 185 | * stream into an array of bytes. | ||
| 186 | * <p> | ||
| 187 | * The <code>read</code> method of <code>InputStream</code> calls | ||
| 188 | * the <code>read</code> method of three arguments with the arguments | ||
| 189 | * <code>b</code>, <code>0</code>, and <code>b.length</code>. | ||
| 190 | * | ||
| 191 | * @param b the buffer into which the data is read. | ||
| 192 | * @return the total number of bytes read into the buffer, or | ||
| 193 | * <code>-1</code> is there is no more data because the end of | ||
| 194 | * the stream has been reached. | ||
| 195 | * @exception IOException if an I/O error occurs. | ||
| 196 | * @see java.io.InputStream#read(byte[], int, int) | ||
| 197 | * @since JCE1.2 | ||
| 198 | */ | ||
| 199 | public int read(byte b[]) throws IOException { | ||
| 200 | return read(b, 0, b.length); | ||
| 201 | } | ||
| 202 | |||
| 203 | /** | ||
| 204 | * Reads up to <code>len</code> bytes of data from this input stream | ||
| 205 | * into an array of bytes. This method blocks until some input is | ||
| 206 | * available. If the first argument is <code>null,</code> up to | ||
| 207 | * <code>len</code> bytes are read and discarded. | ||
| 208 | * | ||
| 209 | * @param b the buffer into which the data is read. | ||
| 210 | * @param off the start offset in the destination array | ||
| 211 | * <code>buf</code> | ||
| 212 | * @param len the maximum number of bytes read. | ||
| 213 | * @return the total number of bytes read into the buffer, or | ||
| 214 | * <code>-1</code> if there is no more data because the end of | ||
| 215 | * the stream has been reached. | ||
| 216 | * @exception IOException if an I/O error occurs. | ||
| 217 | * @see java.io.InputStream#read() | ||
| 218 | * @since JCE1.2 | ||
| 219 | */ | ||
| 220 | public int read(byte b[], int off, int len) throws IOException { | ||
| 221 | if (ostart >= ofinish) { | ||
| 222 | // we loop for new data as the spec says we are blocking | ||
| 223 | int i = 0; | ||
| 224 | while (i == 0) i = getMoreData(); | ||
| 225 | if (i == -1) return -1; | ||
| 226 | } | ||
| 227 | if (len <= 0) { | ||
| 228 | return 0; | ||
| 229 | } | ||
| 230 | int available = ofinish - ostart; | ||
| 231 | if (len < available) available = len; | ||
| 232 | if (b != null) { | ||
| 233 | System.arraycopy(obuffer, ostart, b, off, available); | ||
| 234 | } | ||
| 235 | ostart = ostart + available; | ||
| 236 | return available; | ||
| 237 | } | ||
| 238 | |||
| 239 | /** | ||
| 240 | * Skips <code>n</code> bytes of input from the bytes that can be read | ||
| 241 | * from this input stream without blocking. | ||
| 242 | * | ||
| 243 | * <p>Fewer bytes than requested might be skipped. | ||
| 244 | * The actual number of bytes skipped is equal to <code>n</code> or | ||
| 245 | * the result of a call to | ||
| 246 | * {@link #available() <code>available</code>}, | ||
| 247 | * whichever is smaller. | ||
| 248 | * If <code>n</code> is less than zero, no bytes are skipped. | ||
| 249 | * | ||
| 250 | * <p>The actual number of bytes skipped is returned. | ||
| 251 | * | ||
| 252 | * @param n the number of bytes to be skipped. | ||
| 253 | * @return the actual number of bytes skipped. | ||
| 254 | * @exception IOException if an I/O error occurs. | ||
| 255 | * @since JCE1.2 | ||
| 256 | */ | ||
| 257 | public long skip(long n) throws IOException { | ||
| 258 | int available = ofinish - ostart; | ||
| 259 | if (n > available) { | ||
| 260 | n = available; | ||
| 261 | } | ||
| 262 | if (n < 0) { | ||
| 263 | return 0; | ||
| 264 | } | ||
| 265 | ostart += n; | ||
| 266 | return n; | ||
| 267 | } | ||
| 268 | |||
| 269 | /** | ||
| 270 | * Returns the number of bytes that can be read from this input | ||
| 271 | * stream without blocking. The <code>available</code> method of | ||
| 272 | * <code>InputStream</code> returns <code>0</code>. This method | ||
| 273 | * <B>should</B> be overridden by subclasses. | ||
| 274 | * | ||
| 275 | * @return the number of bytes that can be read from this input stream | ||
| 276 | * without blocking. | ||
| 277 | * @exception IOException if an I/O error occurs. | ||
| 278 | * @since JCE1.2 | ||
| 279 | */ | ||
| 280 | public int available() throws IOException { | ||
| 281 | return (ofinish - ostart); | ||
| 282 | } | ||
| 283 | |||
| 284 | /** | ||
| 285 | * Closes this input stream and releases any system resources | ||
| 286 | * associated with the stream. | ||
| 287 | * <p> | ||
| 288 | * The <code>close</code> method of <code>CipherInputStream</code> | ||
| 289 | * calls the <code>close</code> method of its underlying input | ||
| 290 | * stream. | ||
| 291 | * | ||
| 292 | * @exception IOException if an I/O error occurs. | ||
| 293 | * @since JCE1.2 | ||
| 294 | */ | ||
| 295 | public void close() throws IOException { | ||
| 296 | input.close(); | ||
| 297 | try { | ||
| 298 | // throw away the unprocessed data | ||
| 299 | cipher.doFinal(); | ||
| 300 | } | ||
| 301 | catch (BadPaddingException ex) { | ||
| 302 | } | ||
| 303 | catch (IllegalBlockSizeException ex) { | ||
| 304 | } | ||
| 305 | ostart = 0; | ||
| 306 | ofinish = 0; | ||
| 307 | } | ||
| 308 | |||
| 309 | /** | ||
| 310 | * Tests if this input stream supports the <code>mark</code> | ||
| 311 | * and <code>reset</code> methods, which it does not. | ||
| 312 | * | ||
| 313 | * @return <code>false</code>, since this class does not support the | ||
| 314 | * <code>mark</code> and <code>reset</code> methods. | ||
| 315 | * @see java.io.InputStream#mark(int) | ||
| 316 | * @see java.io.InputStream#reset() | ||
| 317 | * @since JCE1.2 | ||
| 318 | */ | ||
| 319 | public boolean markSupported() { | ||
| 320 | return false; | ||
| 321 | } | ||
| 322 | } | ||