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1: /* OutputBuffer.java -- 2: Copyright (C) 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.javax.crypto.sasl; 40: 41: import gnu.java.security.Registry; 42: import gnu.java.security.util.Util; 43: 44: import java.io.ByteArrayOutputStream; 45: import java.io.IOException; 46: import java.math.BigInteger; 47: 48: /** 49: * The implementation of an outgoing SASL buffer. 50: * <p> 51: * The data elements this class caters for are described in [1]. 52: * <p> 53: * References: 54: * <ol> 55: * <li><a 56: * href="http://www.ietf.org/internet-drafts/draft-burdis-cat-srp-sasl-09.txt"> 57: * Secure Remote Password Authentication Mechanism</a>;<br/> 58: * draft-burdis-cat-srp-sasl-09,<br/> <a 59: * href="mailto:keith@rucus.ru.ac.za">Keith Burdis</a> and <a 60: * href="mailto:raif@forge.com.au">Raïf S. Naffah</a>.</li> 61: * </ol> 62: */ 63: public class OutputBuffer 64: { 65: /** The internal output stream. */ 66: private ByteArrayOutputStream out; 67: 68: public OutputBuffer() 69: { 70: super(); 71: 72: out = new ByteArrayOutputStream(); 73: } 74: 75: /** 76: * Encodes a SASL scalar quantity, <code>count</code>-octet long, to the 77: * current buffer. 78: * 79: * @param count number of octets to encode <code>b</code> with. 80: * @param b the scalar quantity. 81: * @throws SaslEncodingException if an encoding size constraint is violated. 82: * @throws IOException if any other I/O exception occurs during the operation. 83: */ 84: public void setScalar(int count, int b) throws IOException 85: { 86: if (count < 0 || count > 4) 87: throw new SaslEncodingException("Invalid SASL scalar octet count: " 88: + String.valueOf(count)); 89: byte[] element = new byte[count]; 90: for (int i = count; --i >= 0; b >>>= 8) 91: element[i] = (byte) b; 92: out.write(element); 93: } 94: 95: /** 96: * Encodes a SASL OS to the current buffer. 97: * 98: * @param b the OS element. 99: * @throws SaslEncodingException if an encoding size constraint is violated. 100: * @throws IOException if any other I/O exception occurs during the operation. 101: */ 102: public void setOS(byte[] b) throws IOException 103: { 104: final int length = b.length; 105: if (length > Registry.SASL_ONE_BYTE_MAX_LIMIT) 106: throw new SaslEncodingException("SASL octet-sequence too long"); 107: out.write(length & 0xFF); 108: out.write(b); 109: } 110: 111: /** 112: * Encodes a SASL EOS to the current buffer. 113: * 114: * @param b the EOS element. 115: * @throws SaslEncodingException if an encoding size constraint is violated. 116: * @throws IOException if any other I/O exception occurs during the operation. 117: */ 118: public void setEOS(byte[] b) throws IOException 119: { 120: final int length = b.length; 121: if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT) 122: throw new SaslEncodingException("SASL extended octet-sequence too long"); 123: byte[] lengthBytes = { (byte)(length >>> 8), (byte) length }; 124: out.write(lengthBytes); 125: out.write(b); 126: } 127: 128: /** 129: * Encodes a SASL MPI to the current buffer. 130: * 131: * @param val the MPI element. 132: * @throws SaslEncodingException if an encoding size constraint is violated. 133: * @throws IOException if any other I/O exception occurs during the operation. 134: */ 135: public void setMPI(BigInteger val) throws IOException 136: { 137: byte[] b = Util.trim(val); 138: final int length = b.length; 139: if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT) 140: throw new SaslEncodingException("SASL multi-precision integer too long"); 141: byte[] lengthBytes = { (byte)(length >>> 8), (byte) length }; 142: out.write(lengthBytes); 143: out.write(b); 144: } 145: 146: /** 147: * Encodes a SASL Text to the current buffer. 148: * 149: * @param str the Text element. 150: * @throws SaslEncodingException if an encoding size constraint is violated. 151: * @throws SaslEncodingException if the UTF-8 encoding is not supported on 152: * this platform. 153: * @throws IOException if any other I/O exception occurs during the operation. 154: */ 155: public void setText(String str) throws IOException 156: { 157: byte[] b = str.getBytes("UTF8"); 158: final int length = b.length; 159: if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT) 160: throw new SaslEncodingException("SASL text too long"); 161: byte[] lengthBytes = { (byte)(length >>> 8), (byte) length }; 162: out.write(lengthBytes); 163: out.write(b); 164: } 165: 166: /** 167: * Returns the encoded form of the current buffer including the 4-byte length 168: * header. 169: * 170: * @throws SaslEncodingException if an encoding size constraint is violated. 171: */ 172: public byte[] encode() throws SaslEncodingException 173: { 174: byte[] buffer = wrap(); 175: final int length = buffer.length; 176: byte[] result = new byte[length + 4]; 177: result[0] = (byte)(length >>> 24); 178: result[1] = (byte)(length >>> 16); 179: result[2] = (byte)(length >>> 8); 180: result[3] = (byte) length; 181: System.arraycopy(buffer, 0, result, 4, length); 182: return result; 183: } 184: 185: /** 186: * Returns the encoded form of the current buffer excluding the 4-byte length 187: * header. 188: * 189: * @throws SaslEncodingException if an encoding size constraint is violated. 190: */ 191: public byte[] wrap() throws SaslEncodingException 192: { 193: final int length = out.size(); 194: if (length > Registry.SASL_BUFFER_MAX_LIMIT || length < 0) 195: throw new SaslEncodingException("SASL buffer too long"); 196: return out.toByteArray(); 197: } 198: }