- Greg Wilkins (Webtide, LLC)
- Jan Bartel (Webtide, LLC)
- Jesse McConnell (Webtide, LLC)
- Joakim Erdfelt (Webtide, LLC)
- Simone Bordet (Webtide, LLC)
- David Jencks (IBM)
- Olivier Lamy (Webtide, LLC)
//
// ========================================================================
// Copyright (c) 1995-2019 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.util.security;
import java.io.Serializable;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.util.ServiceLoader;
import org.eclipse.jetty.util.TypeUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
Credentials. The Credential class represents an abstract mechanism for checking authentication credentials. A credential instance either represents a secret,
or some data that could only be derived from knowing the secret.
Often a Credential is related to a Password via a one way algorithm, so while a Password itself is a Credential, a UnixCrypt or MD5 digest of a a password is
only a credential that can be checked against the password.
This class includes an implementation for unix Crypt an MD5 digest.
See Also: - Password
/**
* Credentials. The Credential class represents an abstract mechanism for checking authentication credentials. A credential instance either represents a secret,
* or some data that could only be derived from knowing the secret.
* <p>
* Often a Credential is related to a Password via a one way algorithm, so while a Password itself is a Credential, a UnixCrypt or MD5 digest of a a password is
* only a credential that can be checked against the password.
* <p>
* This class includes an implementation for unix Crypt an MD5 digest.
*
* @see Password
*/
public abstract class Credential implements Serializable
{
private static final long serialVersionUID = -7760551052768181572L;
private static final Logger LOG = Log.getLogger(Credential.class);
private static final ServiceLoader<CredentialProvider> CREDENTIAL_PROVIDER_LOADER = ServiceLoader.load(CredentialProvider.class);
Check a credential
Params: - credentials – The credential to check against. This may either be another Credential object, a Password object or a String which is interpreted by this
credential.
Returns: True if the credentials indicated that the shared secret is known to both this Credential and the passed credential.
/**
* Check a credential
*
* @param credentials The credential to check against. This may either be another Credential object, a Password object or a String which is interpreted by this
* credential.
* @return True if the credentials indicated that the shared secret is known to both this Credential and the passed credential.
*/
public abstract boolean check(Object credentials);
Get a credential from a String. If the credential String starts with a known Credential type (eg "CRYPT:" or "MD5:" ) then a Credential of that type is
returned. Otherwise, it tries to find a credential provider whose prefix matches with the start of the credential String. Else the credential is assumed
to be a Password.
Params: - credential – String representation of the credential
Returns: A Credential or Password instance.
/**
* Get a credential from a String. If the credential String starts with a known Credential type (eg "CRYPT:" or "MD5:" ) then a Credential of that type is
* returned. Otherwise, it tries to find a credential provider whose prefix matches with the start of the credential String. Else the credential is assumed
* to be a Password.
*
* @param credential String representation of the credential
* @return A Credential or Password instance.
*/
public static Credential getCredential(String credential)
{
if (credential.startsWith(Crypt.__TYPE))
return new Crypt(credential);
if (credential.startsWith(MD5.__TYPE))
return new MD5(credential);
for (CredentialProvider cp : CREDENTIAL_PROVIDER_LOADER)
{
if (credential.startsWith(cp.getPrefix()))
{
final Credential credentialObj = cp.getCredential(credential);
if (credentialObj != null)
{
return credentialObj;
}
}
}
return new Password(credential);
}
Utility method that replaces String.equals() to avoid timing attacks.
The length of the loop executed will always be the length of the unknown credential
Params: - known – the first string to compare (should be known string)
- unknown – the second string to compare (should be the unknown string)
Returns: whether the two strings are equal
/**
* <p>Utility method that replaces String.equals() to avoid timing attacks.
* The length of the loop executed will always be the length of the unknown credential</p>
*
* @param known the first string to compare (should be known string)
* @param unknown the second string to compare (should be the unknown string)
* @return whether the two strings are equal
*/
protected static boolean stringEquals(String known, String unknown)
{
@SuppressWarnings("ReferenceEquality")
boolean sameObject = (known == unknown);
if (sameObject)
return true;
if (known == null || unknown == null)
return false;
boolean result = true;
int l1 = known.length();
int l2 = unknown.length();
for (int i = 0; i < l2; ++i)
{
result &= ((l1 == 0) ? unknown.charAt(l2 - i - 1) : known.charAt(i % l1)) == unknown.charAt(i);
}
return result && l1 == l2;
}
Utility method that replaces Arrays.equals() to avoid timing attacks.
The length of the loop executed will always be the length of the unknown credential
Params: - known – the first byte array to compare (should be known value)
- unknown – the second byte array to compare (should be unknown value)
Returns: whether the two byte arrays are equal
/**
* <p>Utility method that replaces Arrays.equals() to avoid timing attacks.
* The length of the loop executed will always be the length of the unknown credential</p>
*
* @param known the first byte array to compare (should be known value)
* @param unknown the second byte array to compare (should be unknown value)
* @return whether the two byte arrays are equal
*/
protected static boolean byteEquals(byte[] known, byte[] unknown)
{
if (known == unknown)
return true;
if (known == null || unknown == null)
return false;
boolean result = true;
int l1 = known.length;
int l2 = unknown.length;
for (int i = 0; i < l2; ++i)
{
result &= ((l1 == 0) ? unknown[l2 - i - 1] : known[i % l1]) == unknown[i];
}
return result && l1 == l2;
}
Unix Crypt Credentials
/**
* Unix Crypt Credentials
*/
public static class Crypt extends Credential
{
private static final long serialVersionUID = -2027792997664744210L;
private static final String __TYPE = "CRYPT:";
private final String _cooked;
Crypt(String cooked)
{
_cooked = cooked.startsWith(Crypt.__TYPE) ? cooked.substring(__TYPE.length()) : cooked;
}
@Override
public boolean check(Object credentials)
{
if (credentials instanceof char[])
credentials = new String((char[])credentials);
if (!(credentials instanceof String) && !(credentials instanceof Password))
LOG.warn("Can't check " + credentials.getClass() + " against CRYPT");
return stringEquals(_cooked, UnixCrypt.crypt(credentials.toString(), _cooked));
}
@Override
public boolean equals(Object credential)
{
if (!(credential instanceof Crypt))
return false;
Crypt c = (Crypt)credential;
return stringEquals(_cooked, c._cooked);
}
public static String crypt(String user, String pw)
{
return __TYPE + UnixCrypt.crypt(pw, user);
}
}
MD5 Credentials
/**
* MD5 Credentials
*/
public static class MD5 extends Credential
{
private static final long serialVersionUID = 5533846540822684240L;
private static final String __TYPE = "MD5:";
private static final Object __md5Lock = new Object();
private static MessageDigest __md;
private final byte[] _digest;
MD5(String digest)
{
digest = digest.startsWith(__TYPE) ? digest.substring(__TYPE.length()) : digest;
_digest = TypeUtil.parseBytes(digest, 16);
}
public byte[] getDigest()
{
return _digest;
}
@Override
public boolean check(Object credentials)
{
try
{
if (credentials instanceof char[])
credentials = new String((char[])credentials);
if (credentials instanceof Password || credentials instanceof String)
{
byte[] digest;
synchronized (__md5Lock)
{
if (__md == null)
__md = MessageDigest.getInstance("MD5");
__md.reset();
__md.update(credentials.toString().getBytes(StandardCharsets.ISO_8859_1));
digest = __md.digest();
}
return byteEquals(_digest, digest);
}
else if (credentials instanceof MD5)
{
return equals(credentials);
}
else if (credentials instanceof Credential)
{
// Allow credential to attempt check - i.e. this'll work
// for DigestAuthModule$Digest credentials
return ((Credential)credentials).check(this);
}
else
{
LOG.warn("Can't check " + credentials.getClass() + " against MD5");
return false;
}
}
catch (Exception e)
{
LOG.warn(e);
return false;
}
}
@Override
public boolean equals(Object obj)
{
if (obj instanceof MD5)
return byteEquals(_digest, ((MD5)obj)._digest);
return false;
}
public static String digest(String password)
{
try
{
byte[] digest;
synchronized (__md5Lock)
{
if (__md == null)
{
try
{
__md = MessageDigest.getInstance("MD5");
}
catch (Exception e)
{
LOG.warn(e);
return null;
}
}
__md.reset();
__md.update(password.getBytes(StandardCharsets.ISO_8859_1));
digest = __md.digest();
}
return __TYPE + TypeUtil.toString(digest, 16);
}
catch (Exception e)
{
LOG.warn(e);
return null;
}
}
}
}