Add secure(OnlineAttackSafe|Unique|OfflineAttackSafe)RandomString()

and replace usages of java.util.UUID in Smack with
secureUniqueRandomString() because it uses a thread-local secure random
number generator.
This commit is contained in:
Florian Schmaus 2019-06-02 19:56:56 +02:00
parent 58fc39714f
commit 619b8e6f4a
8 changed files with 89 additions and 60 deletions

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@ -17,6 +17,8 @@
package org.jivesoftware.smack.util;
import java.io.IOException;
import java.nio.CharBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Collection;
import java.util.Iterator;
@ -264,13 +266,9 @@ public class StringUtils {
}
/**
* Array of numbers and letters of mixed case. Numbers appear in the list
* twice so that there is a more equal chance that a number will be picked.
* We can use the array to get a random number or letter by picking a random
* array index.
* 24 upper case characters from the latin alphabet and numbers without '0' and 'O'.
*/
private static final char[] numbersAndLetters = ("0123456789abcdefghijklmnopqrstuvwxyz" +
"ABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
private static final char[] UNAMBIGUOUS_NUMBERS_AND_LETTER = "123456789ABCDEFGHIJKLMNPQRSTUVWXYZ".toCharArray();
/**
* Returns a random String of numbers and letters (lower and upper case)
@ -289,6 +287,74 @@ public class StringUtils {
return randomString(length, RandomUtil.RANDOM.get());
}
public static String secureOnlineAttackSafeRandomString() {
// 34^10 = 2.06e15 possible combinations. Which is enough to protect against online brute force attacks.
// See also https://www.grc.com/haystack.htm
final int REQUIRED_LENGTH = 10;
return randomString(RandomUtil.SECURE_RANDOM.get(), UNAMBIGUOUS_NUMBERS_AND_LETTER, REQUIRED_LENGTH);
}
public static String secureUniqueRandomString() {
// 34^13 = 8.11e19 possible combinations, which is > 2^64.
final int REQUIRED_LENGTH = 13;
return randomString(RandomUtil.SECURE_RANDOM.get(), UNAMBIGUOUS_NUMBERS_AND_LETTER, REQUIRED_LENGTH);
}
/**
* Generate a secure random string with is human readable. The resulting string consists of 24 upper case characters
* from the Latin alphabet and numbers without '0' and 'O', grouped into 4-characters chunks, e.g.
* "TWNK-KD5Y-MT3T-E1GS-DRDB-KVTW". The characters are randomly selected by a cryptographically secure pseudorandom
* number generator (CSPRNG).
* <p>
* The string can be used a backup "code" for secrets, and is in fact the same as the one backup code specified in
* XEP-0373 and the one used by the <a href="https://github.com/open-keychain/open-keychain/wiki/Backups">Backup
* Format v2 of OpenKeychain</a>.
* </p>
*
* @see <a href="https://xmpp.org/extensions/xep-0373.html#backup-encryption"> XEP-0373 §5.4 Encrypting the Secret
* Key Backup</a>
* @return a human readable secure random string.
*/
public static String secureOfflineAttackSafeRandomString() {
// 34^24 = 2^122.10 possible combinations. Which is enough to protect against offline brute force attacks.
// See also https://www.grc.com/haystack.htm
final int REQUIRED_LENGTH = 24;
return randomString(RandomUtil.SECURE_RANDOM.get(), UNAMBIGUOUS_NUMBERS_AND_LETTER, REQUIRED_LENGTH);
}
private static final int RANDOM_STRING_CHUNK_SIZE = 4;
private static String randomString(Random random, char[] alphabet, int numRandomChars) {
// The buffer most hold the size of the requested number of random chars and the chunk separators ('-').
int bufferSize = numRandomChars + ((numRandomChars - 1) / RANDOM_STRING_CHUNK_SIZE);
CharBuffer charBuffer = CharBuffer.allocate(bufferSize);
try {
randomString(charBuffer, random, alphabet, numRandomChars);
} catch (IOException e) {
// This should never happen if we calcuate the buffer size correctly.
throw new AssertionError(e);
}
return charBuffer.flip().toString();
}
private static void randomString(Appendable appendable, Random random, char[] alphabet, int numRandomChars)
throws IOException {
for (int randomCharNum = 1; randomCharNum <= numRandomChars; randomCharNum++) {
int randomIndex = random.nextInt(alphabet.length);
char randomChar = alphabet[randomIndex];
appendable.append(randomChar);
if (randomCharNum % RANDOM_STRING_CHUNK_SIZE == 0 && randomCharNum < numRandomChars) {
appendable.append('-');
}
}
}
public static String randomString(final int length) {
return randomString(length, RandomUtil.SECURE_RANDOM.get());
}
@ -298,24 +364,14 @@ public class StringUtils {
return "";
}
byte[] randomBytes = new byte[length];
random.nextBytes(randomBytes);
char[] randomChars = new char[length];
for (int i = 0; i < length; i++) {
randomChars[i] = getPrintableChar(randomBytes[i]);
int index = random.nextInt(UNAMBIGUOUS_NUMBERS_AND_LETTER.length);
randomChars[i] = UNAMBIGUOUS_NUMBERS_AND_LETTER[index];
}
return new String(randomChars);
}
private static char getPrintableChar(byte indexByte) {
assert (numbersAndLetters.length < Byte.MAX_VALUE * 2);
// Convert indexByte as it where an unsigned byte by promoting it to int
// and masking it with 0xff. Yields results from 0 - 254.
int index = indexByte & 0xff;
return numbersAndLetters[index % numbersAndLetters.length];
}
/**
* Returns true if CharSequence is not null and is not empty, false otherwise.
* Examples:

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@ -1,6 +1,6 @@
/**
*
* Copyright © 2017-2018 Florian Schmaus, 2016-2017 Fernando Ramirez
* Copyright © 2017-2019 Florian Schmaus, 2016-2017 Fernando Ramirez
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@ -23,7 +23,6 @@ import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.WeakHashMap;
import org.jivesoftware.smack.ConnectionCreationListener;
@ -456,7 +455,7 @@ public final class MamManager extends Manager {
public MamQuery queryArchive(MamQueryArgs mamQueryArgs) throws NoResponseException, XMPPErrorException,
NotConnectedException, NotLoggedInException, InterruptedException {
String queryId = UUID.randomUUID().toString();
String queryId = StringUtils.secureUniqueRandomString();
String node = mamQueryArgs.node;
DataForm dataForm = mamQueryArgs.getDataForm();
@ -515,7 +514,7 @@ public final class MamManager extends Manager {
public List<FormField> retrieveFormFields(String node)
throws NoResponseException, XMPPErrorException, NotConnectedException,
InterruptedException, NotLoggedInException {
String queryId = UUID.randomUUID().toString();
String queryId = StringUtils.secureUniqueRandomString();
MamQueryIQ mamQueryIq = new MamQueryIQ(queryId, node, null);
mamQueryIq.setTo(archiveAddress);
@ -601,7 +600,8 @@ public final class MamManager extends Manager {
private List<Message> page(RSMSet requestRsmSet) throws NoResponseException, XMPPErrorException,
NotConnectedException, NotLoggedInException, InterruptedException {
MamQueryIQ mamQueryIQ = new MamQueryIQ(UUID.randomUUID().toString(), node, form);
String queryId = StringUtils.secureUniqueRandomString();
MamQueryIQ mamQueryIQ = new MamQueryIQ(queryId, node, form);
mamQueryIQ.setType(IQ.Type.set);
mamQueryIQ.setTo(archiveAddress);
mamQueryIQ.addExtension(requestRsmSet);

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@ -16,8 +16,6 @@
*/
package org.jivesoftware.smackx.sid.element;
import java.util.UUID;
import org.jivesoftware.smack.packet.ExtensionElement;
import org.jivesoftware.smack.util.StringUtils;
@ -28,7 +26,7 @@ public abstract class StableAndUniqueIdElement implements ExtensionElement {
private final String id;
public StableAndUniqueIdElement() {
this.id = UUID.randomUUID().toString();
this.id = StringUtils.secureUniqueRandomString();
}
public String getId() {

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@ -65,7 +65,7 @@ public class StableUniqueStanzaIdTest extends SmackTestSuite {
OriginIdElement element = new OriginIdElement();
assertNotNull(element);
assertEquals(StableUniqueStanzaIdManager.NAMESPACE, element.getNamespace());
assertEquals(36, element.getId().length());
assertEquals(16, element.getId().length());
}
@Test

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@ -20,7 +20,6 @@ import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.WeakHashMap;
import java.util.concurrent.ConcurrentHashMap;
@ -36,6 +35,7 @@ import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.XMPPException.XMPPErrorException;
import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.packet.StanzaError;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smackx.bytestreams.BytestreamListener;
import org.jivesoftware.smackx.bytestreams.BytestreamManager;
@ -138,9 +138,6 @@ public final class InBandBytestreamManager extends Manager implements Bytestream
/* prefix used to generate session IDs */
private static final String SESSION_ID_PREFIX = "jibb_";
/* random generator to create session IDs */
private static final Random randomGenerator = new Random();
/* stores one InBandBytestreamManager for each XMPP connection */
private static final Map<XMPPConnection, InBandBytestreamManager> managers = new WeakHashMap<>();
@ -490,7 +487,7 @@ public final class InBandBytestreamManager extends Manager implements Bytestream
private static String getNextSessionID() {
StringBuilder buffer = new StringBuilder();
buffer.append(SESSION_ID_PREFIX);
buffer.append(randomGenerator.nextInt(Integer.MAX_VALUE) + randomGenerator.nextInt(Integer.MAX_VALUE));
buffer.append(StringUtils.secureOnlineAttackSafeRandomString());
return buffer.toString();
}

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@ -24,7 +24,6 @@ import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.concurrent.ConcurrentHashMap;
@ -44,6 +43,7 @@ import org.jivesoftware.smack.XMPPException.XMPPErrorException;
import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.packet.Stanza;
import org.jivesoftware.smack.packet.StanzaError;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smackx.bytestreams.BytestreamListener;
import org.jivesoftware.smackx.bytestreams.BytestreamManager;
@ -114,9 +114,6 @@ public final class Socks5BytestreamManager extends Manager implements Bytestream
/* prefix used to generate session IDs */
private static final String SESSION_ID_PREFIX = "js5_";
/* random generator to create session IDs */
private static final Random randomGenerator = new Random();
/* stores one Socks5BytestreamManager for each XMPP connection */
private static final Map<XMPPConnection, Socks5BytestreamManager> managers = new WeakHashMap<>();
@ -759,7 +756,7 @@ public final class Socks5BytestreamManager extends Manager implements Bytestream
private static String getNextSessionID() {
StringBuilder buffer = new StringBuilder();
buffer.append(SESSION_ID_PREFIX);
buffer.append(randomGenerator.nextInt(Integer.MAX_VALUE) + randomGenerator.nextInt(Integer.MAX_VALUE));
buffer.append(StringUtils.secureOnlineAttackSafeRandomString());
return buffer.toString();
}

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@ -20,7 +20,6 @@ package org.jivesoftware.smack.chat;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
import java.util.WeakHashMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;
@ -42,6 +41,7 @@ import org.jivesoftware.smack.filter.ThreadFilter;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Message.Type;
import org.jivesoftware.smack.packet.Stanza;
import org.jivesoftware.smack.util.StringUtils;
import org.jxmpp.jid.EntityBareJid;
import org.jxmpp.jid.EntityJid;
@ -407,7 +407,7 @@ public final class ChatManager extends Manager{
* @return the next id.
*/
private static String nextID() {
return UUID.randomUUID().toString();
return StringUtils.secureUniqueRandomString();
}
public static void setDefaultMatchMode(MatchMode mode) {

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@ -18,9 +18,9 @@ package org.jivesoftware.smackx.ox.util;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.security.SecureRandom;
import java.util.Set;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smack.util.stringencoder.Base64;
import org.jivesoftware.smackx.ox.crypto.OpenPgpProvider;
@ -52,26 +52,7 @@ public class SecretKeyBackupHelper {
* @return backup code
*/
public static String generateBackupPassword() {
final String alphabet = "123456789ABCDEFGHIJKLMNPQRSTUVWXYZ";
final int len = alphabet.length();
SecureRandom random = new SecureRandom();
StringBuilder code = new StringBuilder(29);
// 6 blocks
for (int i = 0; i < 6; i++) {
// of 4 chars
for (int j = 0; j < 4; j++) {
char c = alphabet.charAt(random.nextInt(len));
code.append(c);
}
// dash after every block except the last one
if (i != 5) {
code.append('-');
}
}
return code.toString();
return StringUtils.secureOfflineAttackSafeRandomString();
}
/**