Use thread local variables for (Secure)Randoms

This commit is contained in:
Florian Schmaus 2017-03-10 17:16:53 +01:00
parent 09b6608a3a
commit 1cc9cec677
2 changed files with 27 additions and 8 deletions

View File

@ -1,6 +1,6 @@
/**
*
* Copyright 2014-2016 Florian Schmaus
* Copyright 2014-2017 Florian Schmaus
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@ -22,6 +22,7 @@ import java.security.SecureRandom;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import javax.security.auth.callback.CallbackHandler;
@ -41,7 +42,12 @@ public abstract class ScramMechanism extends SASLMechanism {
private static final byte[] SERVER_KEY_BYTES = toBytes("Server Key");
private static final byte[] ONE = new byte[] { 0, 0, 0, 1 };
private static final SecureRandom RANDOM = new SecureRandom();
private static final ThreadLocal<SecureRandom> SECURE_RANDOM = new ThreadLocal<SecureRandom>() {
@Override
protected SecureRandom initialValue() {
return new SecureRandom();
}
};
private static final Cache<String, Keys> CACHE = new LruCache<String, Keys>(10);
@ -292,8 +298,9 @@ public abstract class ScramMechanism extends SASLMechanism {
String getRandomAscii() {
int count = 0;
char[] randomAscii = new char[RANDOM_ASCII_BYTE_COUNT];
final Random random = SECURE_RANDOM.get();
while (count < RANDOM_ASCII_BYTE_COUNT) {
int r = RANDOM.nextInt(128);
int r = random.nextInt(128);
char c = (char) r;
// RFC 5802 § 5.1 specifies 'r:' to exclude the ',' character and to be only printable ASCII characters
if (!isPrintableNonCommaAsciiChar(c)) {

View File

@ -1,6 +1,6 @@
/**
*
* Copyright 2003-2007 Jive Software, 2016 Florian Schmaus.
* Copyright 2003-2007 Jive Software, 2016-2017 Florian Schmaus.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@ -271,7 +271,12 @@ public class StringUtils {
* The Random class is not considered to be cryptographically secure, so
* only use these random Strings for low to medium security applications.
*/
private static final Random randGen = new Random();
private static final ThreadLocal<Random> randGen = new ThreadLocal<Random>() {
@Override
protected Random initialValue() {
return new Random();
}
};
/**
* Array of numbers and letters of mixed case. Numbers appear in the list
@ -299,15 +304,22 @@ public class StringUtils {
if (length < 1) {
return null;
}
final Random random = randGen.get();
// Create a char buffer to put random letters and numbers in.
char [] randBuffer = new char[length];
for (int i=0; i<randBuffer.length; i++) {
randBuffer[i] = numbersAndLetters[randGen.nextInt(numbersAndLetters.length)];
randBuffer[i] = numbersAndLetters[random.nextInt(numbersAndLetters.length)];
}
return new String(randBuffer);
}
private static final SecureRandom SECURE_RANDOM = new SecureRandom();
private static final ThreadLocal<SecureRandom> SECURE_RANDOM = new ThreadLocal<SecureRandom>() {
@Override
protected SecureRandom initialValue() {
return new SecureRandom();
}
};
public static String randomString(final int length) {
if (length < 1) {
@ -315,7 +327,7 @@ public class StringUtils {
}
byte[] randomBytes = new byte[length];
SECURE_RANDOM.nextBytes(randomBytes);
SECURE_RANDOM.get().nextBytes(randomBytes);
char[] randomChars = new char[length];
for (int i = 0; i < length; i++) {
randomChars[i] = getPrintableChar(randomBytes[i]);