J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999 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 com.sun.jndi.ldap; |
| 27 | |
| 28 | import java.io.UnsupportedEncodingException; |
| 29 | |
| 30 | /** |
| 31 | * A BER decoder. Contains methods to parse a BER buffer. |
| 32 | * |
| 33 | * @author Jagane Sundar |
| 34 | * @author Vincent Ryan |
| 35 | */ |
| 36 | public final class BerDecoder extends Ber { |
| 37 | |
| 38 | private int origOffset; // The start point in buf to decode |
| 39 | |
| 40 | /** |
| 41 | * Creates a BER decoder that reads bytes from the specified buffer. |
| 42 | */ |
| 43 | public BerDecoder(byte buf[], int offset, int bufsize) { |
| 44 | |
| 45 | this.buf = buf; |
| 46 | this.bufsize = bufsize; |
| 47 | this.origOffset = offset; |
| 48 | |
| 49 | reset(); |
| 50 | } |
| 51 | |
| 52 | /** |
| 53 | * Resets this decode to start parsing from the initial offset |
| 54 | * (ie., same state as after calling the constructor). |
| 55 | */ |
| 56 | public void reset() { |
| 57 | offset = origOffset; |
| 58 | } |
| 59 | |
| 60 | /** |
| 61 | * Returns the current parse position. |
| 62 | * It points to the byte that will be parsed next. |
| 63 | * Useful for parsing sequences. |
| 64 | */ |
| 65 | public int getParsePosition() { |
| 66 | return offset; |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * Parses a possibly variable length field. |
| 71 | */ |
| 72 | public int parseLength() throws DecodeException { |
| 73 | |
| 74 | int lengthbyte = parseByte(); |
| 75 | |
| 76 | if ((lengthbyte & 0x80) == 0x80) { |
| 77 | |
| 78 | lengthbyte &= 0x7f; |
| 79 | |
| 80 | if (lengthbyte == 0) { |
| 81 | throw new DecodeException( |
| 82 | "Indefinite length not supported"); |
| 83 | } |
| 84 | |
| 85 | if (lengthbyte > 4) { |
| 86 | throw new DecodeException("encoding too long"); |
| 87 | } |
| 88 | |
| 89 | if (bufsize - offset < lengthbyte) { |
| 90 | throw new DecodeException("Insufficient data"); |
| 91 | } |
| 92 | |
| 93 | int retval = 0; |
| 94 | |
| 95 | for( int i = 0; i < lengthbyte; i++) { |
| 96 | retval = (retval << 8) + (buf[offset++] & 0xff); |
| 97 | } |
| 98 | return retval; |
| 99 | } else { |
| 100 | return lengthbyte; |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Parses the next sequence in this BER buffer. |
| 106 | * @param rlen An array for returning size of the sequence in bytes. If null, |
| 107 | * the size is not returned. |
| 108 | * @return The sequence's tag. |
| 109 | */ |
| 110 | public int parseSeq(int rlen[]) throws DecodeException { |
| 111 | |
| 112 | int seq = parseByte(); |
| 113 | int len = parseLength(); |
| 114 | if (rlen != null) { |
| 115 | rlen[0] = len; |
| 116 | } |
| 117 | return seq; |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Used to skip bytes. Usually used when trying to recover from parse error. |
| 122 | * Don't need to be public right now? |
| 123 | * @param i The number of bytes to skip |
| 124 | */ |
| 125 | void seek(int i) throws DecodeException { |
| 126 | if (offset + i > bufsize || offset + i < 0) { |
| 127 | throw new DecodeException("array index out of bounds"); |
| 128 | } |
| 129 | offset += i; |
| 130 | } |
| 131 | |
| 132 | /** |
| 133 | * Parses the next byte in this BER buffer. |
| 134 | * @return The byte parsed. |
| 135 | */ |
| 136 | public int parseByte() throws DecodeException { |
| 137 | if (bufsize - offset < 1) { |
| 138 | throw new DecodeException("Insufficient data"); |
| 139 | } |
| 140 | return buf[offset++] & 0xff; |
| 141 | } |
| 142 | |
| 143 | |
| 144 | /** |
| 145 | * Returns the next byte in this BER buffer without consuming it. |
| 146 | * @return The next byte. |
| 147 | */ |
| 148 | public int peekByte() throws DecodeException { |
| 149 | if (bufsize - offset < 1) { |
| 150 | throw new DecodeException("Insufficient data"); |
| 151 | } |
| 152 | return buf[offset] & 0xff; |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Parses an ASN_BOOLEAN tagged integer from this BER buffer. |
| 157 | * @return true if the tagged integer is 0; false otherwise. |
| 158 | */ |
| 159 | public boolean parseBoolean() throws DecodeException { |
| 160 | return ((parseIntWithTag(ASN_BOOLEAN) == 0x00) ? false : true); |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * Parses an ASN_ENUMERATED tagged integer from this BER buffer. |
| 165 | * @return The tag of enumeration. |
| 166 | */ |
| 167 | public int parseEnumeration() throws DecodeException { |
| 168 | return parseIntWithTag(ASN_ENUMERATED); |
| 169 | } |
| 170 | |
| 171 | /** |
| 172 | * Parses an ASN_INTEGER tagged integer from this BER buffer. |
| 173 | * @return The value of the integer. |
| 174 | */ |
| 175 | public int parseInt() throws DecodeException { |
| 176 | return parseIntWithTag(ASN_INTEGER); |
| 177 | } |
| 178 | |
| 179 | /** |
| 180 | * Parses an integer that's preceded by a tag. |
| 181 | *<blockquote><pre> |
| 182 | * BER integer ::= tag length byte {byte}* |
| 183 | *</pre></blockquote> |
| 184 | */ |
| 185 | private int parseIntWithTag(int tag) throws DecodeException { |
| 186 | |
| 187 | |
| 188 | if (parseByte() != tag) { |
| 189 | throw new DecodeException("Encountered ASN.1 tag " + |
| 190 | Integer.toString(buf[offset - 1] & 0xff) + |
| 191 | " (expected tag " + Integer.toString(tag) + ")"); |
| 192 | } |
| 193 | |
| 194 | int len = parseLength(); |
| 195 | |
| 196 | if (len > 4) { |
| 197 | throw new DecodeException("INTEGER too long"); |
| 198 | } else if (len > bufsize - offset) { |
| 199 | throw new DecodeException("Insufficient data"); |
| 200 | } |
| 201 | |
| 202 | byte fb = buf[offset++]; |
| 203 | int value = 0; |
| 204 | |
| 205 | value = fb & 0x7F; |
| 206 | for( int i = 1 /* first byte already read */ ; i < len; i++) { |
| 207 | value <<= 8; |
| 208 | value |= (buf[offset++] & 0xff); |
| 209 | } |
| 210 | |
| 211 | if ((fb & 0x80) == 0x80) { |
| 212 | value = -value; |
| 213 | } |
| 214 | |
| 215 | return value; |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * Parses a string. |
| 220 | */ |
| 221 | public String parseString(boolean decodeUTF8) throws DecodeException { |
| 222 | return parseStringWithTag(ASN_SIMPLE_STRING, decodeUTF8, null); |
| 223 | } |
| 224 | |
| 225 | /** |
| 226 | * Parses a string of a given tag from this BER buffer. |
| 227 | *<blockquote><pre> |
| 228 | *BER simple string ::= tag length {byte}* |
| 229 | *</pre></blockquote> |
| 230 | * @param rlen An array for holding the relative parsed offset; if null |
| 231 | * offset not set. |
| 232 | * @param decodeUTF8 If true, use UTF-8 when decoding the string; otherwise |
| 233 | * use ISO-Latin-1 (8859_1). Use true for LDAPv3; false for LDAPv2. |
| 234 | * @param tag The tag that precedes the string. |
| 235 | * @return The non-null parsed string. |
| 236 | */ |
| 237 | public String parseStringWithTag(int tag, boolean decodeUTF8, int rlen[]) |
| 238 | throws DecodeException { |
| 239 | |
| 240 | int st; |
| 241 | int origOffset = offset; |
| 242 | |
| 243 | if ((st = parseByte()) != tag) { |
| 244 | throw new DecodeException("Encountered ASN.1 tag " + |
| 245 | Integer.toString((byte)st) + " (expected tag " + tag + ")"); |
| 246 | } |
| 247 | |
| 248 | int len = parseLength(); |
| 249 | |
| 250 | if (len > bufsize - offset) { |
| 251 | throw new DecodeException("Insufficient data"); |
| 252 | } |
| 253 | |
| 254 | String retstr; |
| 255 | if (len == 0) { |
| 256 | retstr = ""; |
| 257 | } else { |
| 258 | byte[] buf2 = new byte[len]; |
| 259 | |
| 260 | System.arraycopy(buf, offset, buf2, 0, len); |
| 261 | if (decodeUTF8) { |
| 262 | try { |
| 263 | retstr = new String(buf2, "UTF8"); |
| 264 | } catch (UnsupportedEncodingException e) { |
| 265 | throw new DecodeException("UTF8 not available on platform"); |
| 266 | } |
| 267 | } else { |
| 268 | try { |
| 269 | retstr = new String(buf2, "8859_1"); |
| 270 | } catch (UnsupportedEncodingException e) { |
| 271 | throw new DecodeException("8859_1 not available on platform"); |
| 272 | } |
| 273 | } |
| 274 | offset += len; |
| 275 | } |
| 276 | |
| 277 | if (rlen != null) { |
| 278 | rlen[0] = offset - origOffset; |
| 279 | } |
| 280 | |
| 281 | return retstr; |
| 282 | } |
| 283 | |
| 284 | /** |
| 285 | * Parses an octet string of a given type(tag) from this BER buffer. |
| 286 | * <blockquote><pre> |
| 287 | * BER Binary Data of type "tag" ::= tag length {byte}* |
| 288 | *</pre></blockquote> |
| 289 | * |
| 290 | * @param tag The tag to look for. |
| 291 | * @param rlen An array for returning the relative parsed position. If null, |
| 292 | * the relative parsed position is not returned. |
| 293 | * @return A non-null array containing the octet string. |
| 294 | * @throws DecodeException If the next byte in the BER buffer is not |
| 295 | * <tt>tag</tt>, or if length specified in the BER buffer exceeds the |
| 296 | * number of bytes left in the buffer. |
| 297 | */ |
| 298 | public byte[] parseOctetString(int tag, int rlen[]) throws DecodeException { |
| 299 | |
| 300 | int origOffset = offset; |
| 301 | int st; |
| 302 | if ((st = parseByte()) != tag) { |
| 303 | |
| 304 | throw new DecodeException("Encountered ASN.1 tag " + |
| 305 | Integer.toString(st) + |
| 306 | " (expected tag " + Integer.toString(tag) + ")"); |
| 307 | } |
| 308 | |
| 309 | int len = parseLength(); |
| 310 | |
| 311 | if (len > bufsize - offset) { |
| 312 | throw new DecodeException("Insufficient data"); |
| 313 | } |
| 314 | |
| 315 | byte retarr[] = new byte[len]; |
| 316 | if (len > 0) { |
| 317 | System.arraycopy(buf, offset, retarr, 0, len); |
| 318 | offset += len; |
| 319 | } |
| 320 | |
| 321 | if (rlen != null) { |
| 322 | rlen[0] = offset - origOffset; |
| 323 | } |
| 324 | |
| 325 | return retarr; |
| 326 | } |
| 327 | |
| 328 | /** |
| 329 | * Returns the number of unparsed bytes in this BER buffer. |
| 330 | */ |
| 331 | public int bytesLeft() { |
| 332 | return bufsize - offset; |
| 333 | } |
| 334 | } |