| /* InputBuffer.java -- |
| Copyright (C) 2003, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.javax.crypto.sasl; |
| |
| import gnu.java.security.Registry; |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.IOException; |
| import java.math.BigInteger; |
| |
| /** |
| * The implementation of an incoming SASL buffer. |
| * <p> |
| * The data elements this class caters for are described in [1]. |
| * <p> |
| * References: |
| * <ol> |
| * <li><a |
| * href="http://www.ietf.org/internet-drafts/draft-burdis-cat-srp-sasl-09.txt"> |
| * Secure Remote Password Authentication Mechanism</a>;<br/> |
| * draft-burdis-cat-srp-sasl-09,<br/> <a |
| * href="mailto:keith@rucus.ru.ac.za">Keith Burdis</a> and <a |
| * href="mailto:raif@forge.com.au">Raïf S. Naffah</a>.</li> |
| * </ol> |
| */ |
| public class InputBuffer |
| { |
| /** The internal buffer stream containing the buffer's contents. */ |
| protected ByteArrayInputStream in; |
| /** The length of the buffer, according to its header. */ |
| protected int length; |
| |
| /** |
| * Constructs a SASL buffer given the buffer's encoded form, including its |
| * header bytes. |
| * |
| * @param frame the encoded form, including the header bytes, of a SASL |
| * buffer. |
| * @throws SaslEncodingException if the buffer is malformed. |
| */ |
| public InputBuffer(byte[] frame) throws SaslEncodingException |
| { |
| this(); |
| |
| if (frame.length < 4) |
| throw new SaslEncodingException("SASL buffer header too short"); |
| length = (frame[0] & 0xFF) << 24 |
| | (frame[1] & 0xFF) << 16 |
| | (frame[2] & 0xFF) << 8 |
| | (frame[3] & 0xFF); |
| if (length > Registry.SASL_BUFFER_MAX_LIMIT || length < 0) |
| throw new SaslEncodingException("SASL buffer size limit exceeded"); |
| in = new ByteArrayInputStream(frame, 4, length); |
| } |
| |
| /** Trivial private constructor for use by the class method. */ |
| private InputBuffer() |
| { |
| super(); |
| } |
| |
| /** |
| * Returns an instance of a SASL buffer given the buffer's encoded contents, |
| * excluding the buffer's header bytes. |
| * <p> |
| * Calls the method with the same name and three arguments as: |
| * <code>getInstance(raw, 0, raw.length)</code>. |
| * |
| * @param raw the encoded form, excluding the header bytes, of a SASL buffer. |
| * @return a new instance of {@link InputBuffer}. |
| */ |
| public static InputBuffer getInstance(byte[] raw) |
| { |
| return getInstance(raw, 0, raw.length); |
| } |
| |
| /** |
| * Returns an instance of a SASL buffer given the buffer's encoded contents, |
| * excluding the buffer's header bytes. |
| * |
| * @param raw the encoded form, excluding the header bytes, of a SASL buffer. |
| * @param offset offset where to start using raw bytes from. |
| * @param len number of bytes to use. |
| * @return a new instance of {@link InputBuffer}. |
| */ |
| public static InputBuffer getInstance(byte[] raw, int offset, int len) |
| { |
| InputBuffer result = new InputBuffer(); |
| result.in = new ByteArrayInputStream(raw, offset, len); |
| return result; |
| } |
| |
| /** |
| * Converts two octets into the number that they represent. |
| * |
| * @param b the two octets. |
| * @return the length. |
| */ |
| public static int twoBytesToLength(byte[] b) throws SaslEncodingException |
| { |
| final int result = (b[0] & 0xFF) << 8 | (b[1] & 0xFF); |
| if (result > Registry.SASL_TWO_BYTE_MAX_LIMIT) |
| throw new SaslEncodingException("SASL MPI/Text size limit exceeded"); |
| return result; |
| } |
| |
| public boolean hasMoreElements() |
| { |
| return (in.available() > 0); |
| } |
| |
| /** |
| * Decodes a SASL scalar quantity, <code>count</code>-octet long, from the |
| * current buffer. |
| * |
| * @param count the number of octets of this scalar quantity. |
| * @return a native representation of a SASL scalar (unsigned integer) |
| * quantity. |
| * @throws SaslEncodingException if an encoding exception occurs during the |
| * operation. |
| * @throws IOException if any other I/O exception occurs during the operation. |
| */ |
| public long getScalar(int count) throws IOException |
| { |
| if (count < 0 || count > 4) |
| throw new SaslEncodingException("Invalid SASL scalar octet count: " |
| + String.valueOf(count)); |
| if (! hasMoreElements()) |
| throw new SaslEncodingException("Not enough bytes for a scalar in buffer"); |
| if (in.available() < count) |
| throw new SaslEncodingException("Illegal SASL scalar encoding"); |
| byte[] element = new byte[count]; |
| in.read(element); |
| long result = 0L; |
| for (int i = 0; i < count; i++) |
| { |
| result <<= 8; |
| result |= element[i] & 0xFFL; |
| } |
| return result; |
| } |
| |
| /** |
| * Decodes a SASL OS from the current buffer. |
| * |
| * @return a native representation of a SASL OS. |
| * @throws SaslEncodingException if an encoding exception occurs during the |
| * operation. |
| * @throws IOException if any other I/O exception occurs during the operation. |
| */ |
| public byte[] getOS() throws IOException |
| { |
| if (! hasMoreElements()) |
| throw new SaslEncodingException( |
| "Not enough bytes for an octet-sequence in buffer"); |
| final int elementLength = in.read(); |
| if (elementLength > Registry.SASL_ONE_BYTE_MAX_LIMIT) |
| throw new SaslEncodingException("SASL octet-sequence size limit exceeded"); |
| if (in.available() < elementLength) |
| throw new SaslEncodingException("Illegal SASL octet-sequence encoding"); |
| byte[] result = new byte[elementLength]; |
| in.read(result); |
| return result; |
| } |
| |
| /** |
| * Decodes a SASL EOS from the current buffer. |
| * |
| * @return a native representation of a SASL EOS. |
| * @throws SaslEncodingException if an encoding exception occurs during the |
| * operation. |
| * @throws IOException if any other I/O exception occurs during the operation. |
| */ |
| public byte[] getEOS() throws IOException |
| { |
| if (in.available() < 2) |
| throw new SaslEncodingException( |
| "Not enough bytes for an extended octet-sequence in buffer"); |
| byte[] elementLengthBytes = new byte[2]; |
| in.read(elementLengthBytes); |
| final int elementLength = twoBytesToLength(elementLengthBytes); |
| if (in.available() < elementLength) |
| throw new SaslEncodingException( |
| "Illegal SASL extended octet-sequence encoding"); |
| byte[] result = new byte[elementLength]; |
| in.read(result); |
| return result; |
| } |
| |
| /** |
| * Decodes a SASL MPI from the current buffer. |
| * |
| * @return a native representation of a SASL MPI. |
| * @throws SaslEncodingException if an encoding exception occurs during the |
| * operation. |
| * @throws IOException if any other I/O exception occurs during the operation. |
| */ |
| public BigInteger getMPI() throws IOException |
| { |
| if (in.available() < 2) |
| throw new SaslEncodingException("Not enough bytes for an MPI in buffer"); |
| byte[] elementLengthBytes = new byte[2]; |
| in.read(elementLengthBytes); |
| final int elementLength = twoBytesToLength(elementLengthBytes); |
| if (in.available() < elementLength) |
| throw new SaslEncodingException( |
| "Illegal SASL multi-precision integer encoding"); |
| byte[] element = new byte[elementLength]; |
| in.read(element); |
| return new BigInteger(1, element); |
| } |
| |
| /** |
| * Decodes a SASL Text from the current buffer. |
| * |
| * @return a native representation of a SASL Text. |
| * @throws SaslEncodingException if an encoding exception occurs during the |
| * operation. |
| * @throws SaslEncodingException if the UTF-8 character encoding is not |
| * supported on this platform. |
| * @throws IOException if any other I/O exception occurs during the operation. |
| */ |
| public String getText() throws IOException |
| { |
| if (in.available() < 2) |
| throw new SaslEncodingException("Not enough bytes for a text in buffer"); |
| byte[] elementLengthBytes = new byte[2]; |
| in.read(elementLengthBytes); |
| final int elementLength = twoBytesToLength(elementLengthBytes); |
| if (in.available() < elementLength) |
| throw new SaslEncodingException("Illegal SASL text encoding"); |
| byte[] element = new byte[elementLength]; |
| in.read(element); |
| return new String(element, "UTF8"); |
| } |
| } |