CRAMMD5SASLMechanismHandler.java revision ea1068c292e9b341af6d6b563cd8988a96be20a9
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at legal-notices/CDDLv1_0.txt.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information:
* Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
*
* Copyright 2006-2009 Sun Microsystems, Inc.
* Portions Copyright 2011-2015 ForgeRock AS.
*/
/**
* This class provides an implementation of a SASL mechanism that uses digest
* authentication via CRAM-MD5. This is a password-based mechanism that does
* not expose the password itself over the wire but rather uses an MD5 hash that
* proves the client knows the password. This is similar to the DIGEST-MD5
* mechanism, and the primary differences are that CRAM-MD5 only obtains random
* data from the server (whereas DIGEST-MD5 uses random data from both the
* server and the client), CRAM-MD5 does not allow for an authorization ID in
* addition to the authentication ID where DIGEST-MD5 does, and CRAM-MD5 does
* not define any integrity and confidentiality mechanisms where DIGEST-MD5
* does. This implementation is based on the proposal defined in
* draft-ietf-sasl-crammd5-05.
*/
public class CRAMMD5SASLMechanismHandler
implements ConfigurationChangeListener<
{
// An array filled with the inner pad byte.
private byte[] iPad;
// An array filled with the outer pad byte.
private byte[] oPad;
// The current configuration for this SASL mechanism handler.
// The identity mapper that will be used to map ID strings to user entries.
private IdentityMapper<?> identityMapper;
// The message digest engine that will be used to create the MD5 digests.
private MessageDigest md5Digest;
// The lock that will be used to provide threadsafe access to the message
// digest.
private Object digestLock;
// The random number generator that we will use to create the server
// challenge.
private SecureRandom randomGenerator;
/**
* Creates a new instance of this SASL mechanism handler. No initialization
* should be done in this method, as it should all be performed in the
* <CODE>initializeSASLMechanismHandler</CODE> method.
*/
public CRAMMD5SASLMechanismHandler()
{
super();
}
/**
* {@inheritDoc}
*/
public void initializeSASLMechanismHandler(
{
// Initialize the variables needed for the MD5 digest creation.
digestLock = new Object();
randomGenerator = new SecureRandom();
try
{
}
catch (Exception e)
{
logger.traceException(e);
throw new InitializationException(message, e);
}
// Create and fill the iPad and oPad arrays.
iPad = new byte[HMAC_MD5_BLOCK_LENGTH];
oPad = new byte[HMAC_MD5_BLOCK_LENGTH];
// Get the identity mapper that should be used to find users.
}
/**
* {@inheritDoc}
*/
public void finalizeSASLMechanismHandler()
{
}
/**
* {@inheritDoc}
*/
{
// The CRAM-MD5 bind process uses two stages. See if the client provided
// any credentials. If not, then we're in the first stage so we'll send the
// challenge to the client.
if (clientCredentials == null)
{
// The client didn't provide any credentials, so this is the initial
// request. Generate some random data to send to the client as the
// challenge and store it in the client connection so we can verify the
// credentials provided by the client later.
byte[] challengeBytes = new byte[16];
for (byte b : challengeBytes)
{
}
return;
}
// If we've gotten here, then the client did provide credentials. First,
// make sure that we have a stored version of the credentials associated
// with the client connection. If not, then it likely means that the client
// is trying to pull a fast one on us.
if (saslStateInfo == null)
{
return;
}
if (! (saslStateInfo instanceof ByteString))
{
return;
}
// Wipe out the stored challenge so it can't be used again.
// Now look at the client credentials and make sure that we can decode them.
// It should be a username followed by a space and a digest string. Since
// the username itself may contain spaces but the digest string may not,
// look for the last space and use it as the delimiter.
if (spacePos < 0)
{
return;
}
// Look at the digest portion of the provided credentials. It must have a
// length of exactly 32 bytes and be comprised only of hex characters.
{
(2*MD5_DIGEST_LENGTH));
return;
}
byte[] digestBytes;
try
{
}
catch (ParseException pe)
{
pe.getMessage());
return;
}
// Get the user entry for the authentication ID. Allow for an
// authentication ID that is just a username (as per the CRAM-MD5 spec), but
// also allow a value in the authzid form specified in RFC 2829.
{
// Try to decode the user DN and retrieve the corresponding entry.
try
{
}
catch (DirectoryException de)
{
return;
}
{
return;
}
{
}
// Acquire a read lock on the user entry. If this fails, then so will the
// authentication.
{
return;
}
try
{
}
catch (DirectoryException de)
{
LocalizableMessage message = ERR_SASLCRAMMD5_CANNOT_GET_ENTRY_BY_DN.get(userDN, de.getMessageObject());
return;
}
finally
{
}
}
else
{
// Use the identity mapper to resolve the username to an entry.
{
}
try
{
}
catch (DirectoryException de)
{
LocalizableMessage message = ERR_SASLCRAMMD5_CANNOT_MAP_USERNAME.get(userName, de.getMessageObject());
return;
}
}
// At this point, we should have a user entry. If we don't then fail.
{
return;
}
else
{
}
// Get the clear-text passwords from the user entry, if there are any.
try
{
userEntry, false);
if (!authState.isPasswordPolicy())
{
return;
}
{
return;
}
}
catch (Exception e)
{
LocalizableMessage message = ERR_SASLCRAMMD5_CANNOT_GET_REVERSIBLE_PASSWORDS.get( userEntry.getName(), e);
return;
}
// Iterate through the clear-text values and see if any of them can be used
// in conjunction with the challenge to construct the provided digest.
boolean matchFound = false;
{
{
matchFound = true;
break;
}
}
if (! matchFound)
{
return;
}
// If we've gotten here, then the authentication was successful.
}
/**
* Generates the appropriate HMAC-MD5 digest for a CRAM-MD5 authentication
* with the given information.
*
* @param password The clear-text password to use when generating the
* digest.
* @param challenge The server-supplied challenge to use when generating the
* digest.
*
* @return The generated HMAC-MD5 digest for CRAM-MD5 authentication.
*/
{
// Get the byte arrays backing the password and challenge.
byte[] p = password.toByteArray();
byte[] c = challenge.toByteArray();
// Grab a lock to protect the MD5 digest generation.
synchronized (digestLock)
{
// If the password is longer than the HMAC-MD5 block length, then use an
// MD5 digest of the password rather than the password itself.
if (p.length > HMAC_MD5_BLOCK_LENGTH)
{
}
// Create byte arrays with data needed for the hash generation.
// Iterate through the bytes in the key and XOR them with the iPad and
// oPad as appropriate.
for (int i=0; i < p.length; i++)
{
iPadAndData[i] ^= p[i];
oPadAndHash[i] ^= p[i];
}
// Copy an MD5 digest of the iPad-XORed key and the data into the array to
// be hashed.
// Return an MD5 digest of the resulting array.
}
}
/**
* {@inheritDoc}
*/
{
// This is a password-based mechanism.
return true;
}
/**
* {@inheritDoc}
*/
{
// This may be considered a secure mechanism.
return true;
}
/**
* {@inheritDoc}
*/
public boolean isConfigurationAcceptable(
{
}
/**
* {@inheritDoc}
*/
public boolean isConfigurationChangeAcceptable(
{
return true;
}
/**
* {@inheritDoc}
*/
{
return ccr;
}
}