1 /* 2 * Copyright (C) 2009 Google Inc. All rights reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.polo.pairing; 18 19 import com.google.polo.exception.PoloException; 20 21 import java.math.BigInteger; 22 import java.security.cert.Certificate; 23 24 import javax.net.ssl.SSLPeerUnverifiedException; 25 import javax.net.ssl.SSLSession; 26 27 /** 28 * Utility methods of general usefulness to the Polo library. 29 */ 30 public class PoloUtil { 31 32 /** 33 * Returns the peer {@link Certificate} for an {@link SSLSession}. 34 * 35 * @throws PoloException if the peer certificate could not be obtained 36 * from the {@link SSLSession}. 37 * @return the {@link Certificate} of the peer 38 */ getPeerCert(SSLSession session)39 public static Certificate getPeerCert(SSLSession session) 40 throws PoloException { 41 try { 42 // Peer certificate 43 Certificate[] certs = session.getPeerCertificates(); 44 if (certs == null || certs.length < 1) { 45 throw new PoloException("No peer certificate."); 46 } 47 return certs[0]; 48 } catch (SSLPeerUnverifiedException e) { 49 throw new PoloException(e); 50 } 51 } 52 53 /** 54 * Return the local {@link Certificate} for an {@link SSLSession}. 55 * 56 * @throws PoloException if the local certificate could not be obtained 57 * from the {@link SSLSession} 58 * @return the {@link Certificate} of the peer 59 */ getLocalCert(SSLSession session)60 public static Certificate getLocalCert(SSLSession session) 61 throws PoloException { 62 Certificate[] certs = session.getLocalCertificates(); 63 if (certs == null || certs.length < 1) { 64 throw new PoloException("No local certificate."); 65 } 66 return certs[0]; 67 } 68 69 /** 70 * Converts an array of bytes to a string of hexadecimal characters. 71 * Leading null bytes are preserved in the output. 72 * <p> 73 * The input byte stream is assumed to be a positive, two's complement 74 * representation of an integer. The return value is the hexadecimal string 75 * representation of this value. 76 * 77 * @param bytes the bytes to convert 78 * @return the string representation 79 */ bytesToHexString(byte[] bytes)80 public static String bytesToHexString(byte[] bytes) { 81 if (bytes == null || bytes.length == 0) { 82 return ""; 83 } 84 BigInteger bigint = new BigInteger(1, bytes); 85 int formatLen = bytes.length * 2; 86 return String.format("%0" + formatLen + "x", bigint); 87 } 88 89 /** 90 * Converts a string of hex characters to a byte array. 91 * 92 * @param hexstr the string of hex characters 93 * @return a byte array representation 94 */ hexStringToBytes(String hexstr)95 public static byte[] hexStringToBytes(String hexstr) { 96 if (hexstr == null || hexstr.length() == 0 || (hexstr.length() % 2) != 0) { 97 throw new IllegalArgumentException("Bad input string."); 98 } 99 100 byte[] result = new byte[hexstr.length() / 2]; 101 for (int i=0; i < result.length; i++) { 102 result[i] = (byte) Integer.parseInt(hexstr.substring(2 * i, 2 * (i + 1)), 103 16); 104 } 105 return result; 106 } 107 108 /** 109 * Converts an integer value to the big endian 4-byte representation. 110 */ intToBigEndianIntBytes(int intVal)111 public static final byte[] intToBigEndianIntBytes(int intVal) { 112 byte[] outBuf = new byte[4]; 113 outBuf[0] = (byte)((intVal >> 24) & 0xff); 114 outBuf[1] = (byte)((intVal >> 16) & 0xff); 115 outBuf[2] = (byte)((intVal >> 8) & 0xff); 116 outBuf[3] = (byte)(intVal & 0xff); 117 return outBuf; 118 } 119 120 /** 121 * Converts a 4-byte array of bytes to an unsigned long value. 122 */ intBigEndianBytesToLong(byte[] input)123 public static final long intBigEndianBytesToLong(byte[] input) { 124 assert (input.length == 4); 125 long ret = (long)(input[0]) & 0xff; 126 ret <<= 8; 127 ret |= (long)(input[1]) & 0xff; 128 ret <<= 8; 129 ret |= (long)(input[2]) & 0xff; 130 ret <<= 8; 131 ret |= (long)(input[3]) & 0xff; 132 return ret; 133 } 134 135 } 136