128 lines
3.8 KiB
Java
128 lines
3.8 KiB
Java
package eu.siacs.conversations.utils;
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import java.security.SecureRandom;
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import java.text.Normalizer;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.Iterator;
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import java.util.LinkedHashSet;
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import java.util.List;
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import eu.siacs.conversations.Config;
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public final class CryptoHelper {
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public static final String FILETRANSFER = "?FILETRANSFERv1:";
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private final static char[] hexArray = "0123456789abcdef".toCharArray();
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private final static char[] vowels = "aeiou".toCharArray();
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private final static char[] consonants = "bcdfghjklmnpqrstvwxyz".toCharArray();
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final public static byte[] ONE = new byte[] { 0, 0, 0, 1 };
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public static String bytesToHex(byte[] bytes) {
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char[] hexChars = new char[bytes.length * 2];
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for (int j = 0; j < bytes.length; j++) {
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int v = bytes[j] & 0xFF;
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hexChars[j * 2] = hexArray[v >>> 4];
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hexChars[j * 2 + 1] = hexArray[v & 0x0F];
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}
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return new String(hexChars);
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}
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public static byte[] hexToBytes(String hexString) {
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int len = hexString.length();
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byte[] array = new byte[len / 2];
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for (int i = 0; i < len; i += 2) {
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array[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4) + Character
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.digit(hexString.charAt(i + 1), 16));
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}
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return array;
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}
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public static String hexToString(final String hexString) {
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return new String(hexToBytes(hexString));
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}
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public static byte[] concatenateByteArrays(byte[] a, byte[] b) {
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byte[] result = new byte[a.length + b.length];
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System.arraycopy(a, 0, result, 0, a.length);
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System.arraycopy(b, 0, result, a.length, b.length);
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return result;
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}
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public static String randomMucName(SecureRandom random) {
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return randomWord(3, random) + "." + randomWord(7, random);
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}
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private static String randomWord(int lenght, SecureRandom random) {
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StringBuilder builder = new StringBuilder(lenght);
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for (int i = 0; i < lenght; ++i) {
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if (i % 2 == 0) {
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builder.append(consonants[random.nextInt(consonants.length)]);
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} else {
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builder.append(vowels[random.nextInt(vowels.length)]);
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}
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}
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return builder.toString();
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}
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/**
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* Escapes usernames or passwords for SASL.
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*/
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public static String saslEscape(final String s) {
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final StringBuilder sb = new StringBuilder((int) (s.length() * 1.1));
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for (int i = 0; i < s.length(); i++) {
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char c = s.charAt(i);
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switch (c) {
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case ',':
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sb.append("=2C");
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break;
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case '=':
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sb.append("=3D");
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break;
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default:
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sb.append(c);
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break;
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}
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}
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return sb.toString();
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}
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public static String saslPrep(final String s) {
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return Normalizer.normalize(s, Normalizer.Form.NFKC);
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}
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public static String prettifyFingerprint(String fingerprint) {
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if (fingerprint.length() < 40) {
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return fingerprint;
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}
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StringBuilder builder = new StringBuilder(fingerprint);
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builder.insert(8, " ");
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builder.insert(17, " ");
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builder.insert(26, " ");
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builder.insert(35, " ");
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return builder.toString();
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}
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public static String[] getOrderedCipherSuites(final String[] platformSupportedCipherSuites) {
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final Collection<String> cipherSuites = new LinkedHashSet<>(Arrays.asList(Config.ENABLED_CIPHERS));
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final List<String> platformCiphers = Arrays.asList(platformSupportedCipherSuites);
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cipherSuites.retainAll(platformCiphers);
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cipherSuites.addAll(platformCiphers);
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filterWeakCipherSuites(cipherSuites);
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return cipherSuites.toArray(new String[cipherSuites.size()]);
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}
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private static void filterWeakCipherSuites(final Collection<String> cipherSuites) {
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final Iterator<String> it = cipherSuites.iterator();
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while (it.hasNext()) {
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String cipherName = it.next();
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// remove all ciphers with no or very weak encryption or no authentication
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for (String weakCipherPattern : Config.WEAK_CIPHER_PATTERNS) {
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if (cipherName.contains(weakCipherPattern)) {
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it.remove();
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break;
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}
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}
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}
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}
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}
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