Package org.jivesoftware.openfire.sasl

Class ScramSha256SaslServer

java.lang.Object

org.jivesoftware.openfire.sasl.ScramSaslServer

org.jivesoftware.openfire.sasl.ScramSha256SaslServer

All Implemented Interfaces:

SaslServer

public class ScramSha256SaslServer
extends ScramSaslServer

Implements the SCRAM-SHA-256 (and its channel binding -PLUS variant) server-side mechanism. The SCRAM exchange itself is implemented by the hash-agnostic ScramSaslServer superclass. This class binds that exchange to the SHA-256 hash function. As described in ScramSaslServer, instances are session-specific and must not be reused across sessions or users. In particular, the instance must retain the mechanism availability for its session when processing GS2 channel-binding negotiation.

Author:

Guus der Kinderen

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DIGEST_ALGORITHM_NAME	The JCA name of the message digest that corresponds to this mechanism's hash function.
static final String	HMAC_ALGORITHM_NAME	The JCA name of the HMAC algorithm that corresponds to this mechanism's hash function
static final SystemProperty<Integer>	ITERATION_COUNT
static final String	MECHANISM_NAME	The IANA-registered name of the base (non-PLUS) mechanism implemented by this server.

Fields inherited from class org.jivesoftware.openfire.sasl.ScramSaslServer

PROPNAME_CHANNELBINDINGTYPE

Constructor Summary

Constructors

Constructor	Description
ScramSha256SaslServer(boolean isPlusMechanism, Map<String,?> props, Set<String> availableMechanismsForSession)	Creates a new, client-specific, instance.

Method Summary

Modifier and Type	Method	Description
protected int	getDefaultIterationCount()	The iteration count to advertise when no per-user value is available.
protected String	getDigestAlgorithmName()	The JCA name of the message digest that corresponds to this mechanism's hash function, for example SHA-1.
protected String	getHmacAlgorithmName()	The JCA name of the HMAC algorithm that corresponds to this mechanism's hash function, for example HmacSHA1.
protected String	getMechanismBaseName()	The IANA-registered name of the base (non-PLUS) mechanism implemented by this server, for example SCRAM-SHA-1.
protected String	getNonExistentUserSecret()	A server-side secret from which deterministic fake credentials are derived for non-existent users, so that authentication processing for non-existing users is indistinguishable from that of existing users.
static String	getServerSecretForNonExistentUsers()	Retrieves a server-side secret used when handling authentication attempts for non-existing users in SCRAM-SHA-256 (-PLUS).

Methods inherited from class org.jivesoftware.openfire.sasl.ScramSaslServer

dispose, evaluateResponse, extractRawGS2Header, getAuthorizationID, getMechanismName, getNegotiatedProperty, getOrCreateSalt, getOrFakeServerKey, getOrFakeStoredKey, isComplete, unwrap, wrap

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

MECHANISM_NAME

public static final String MECHANISM_NAME

The IANA-registered name of the base (non-PLUS) mechanism implemented by this server.

See Also:

• Constant Field Values

HMAC_ALGORITHM_NAME

public static final String HMAC_ALGORITHM_NAME

The JCA name of the HMAC algorithm that corresponds to this mechanism's hash function

See Also:

• Constant Field Values

DIGEST_ALGORITHM_NAME

public static final String DIGEST_ALGORITHM_NAME

The JCA name of the message digest that corresponds to this mechanism's hash function.

See Also:

• Constant Field Values

ITERATION_COUNT

public static final SystemProperty<Integer> ITERATION_COUNT

Constructor Details

ScramSha256SaslServer

public ScramSha256SaslServer(boolean isPlusMechanism,
 Map<String,?> props,
 @Nonnull
 Set<String> availableMechanismsForSession)

Creates a new, client-specific, instance.

Parameters:

isPlusMechanism - Denotes if this instance supports channel-binding (true) or not (false).

props - The possibly null set of properties used to select the SASL mechanism and to configure the authentication exchange of the selected mechanism.

availableMechanismsForSession - The names of SASL mechanisms that are available to this particular session (as opposed to the set of globally available mechanism names).

Method Details

getServerSecretForNonExistentUsers

public static String getServerSecretForNonExistentUsers()

Retrieves a server-side secret used when handling authentication attempts for non-existing users in SCRAM-SHA-256 (-PLUS). This method ensures that the one-time initialization that is required for usage will occur. Instead of failing immediately, the server derives deterministic, fake SCRAM credentials (such as stored keys, server keys, and where applicable salt values) based on this secret. This ensures that authentication processing for non-existing users is indistinguishable from that of existing users. This mechanism helps protect against user enumeration attacks by preventing observable differences in behavior between existing and non-existing accounts. Changing (rotating) this value will cause different derived values to be generated for non-existing users. This does not affect authentication of existing users but can invalidate consistency of ongoing or repeated authentication attempts for non-existing users.

See Also:

• OF-3258: Guard against user enumeration in ScramSha1SaslServer

getMechanismBaseName

protected String getMechanismBaseName()

Description copied from class: ScramSaslServer

The IANA-registered name of the base (non-PLUS) mechanism implemented by this server, for example SCRAM-SHA-1. This value is also the key under which SCRAM credentials for this mechanism are stored: the -PLUS variant shares the credential of the base mechanism.

Specified by:

getMechanismBaseName in class ScramSaslServer

Returns:

A non-null string representing the IANA-registered (base) mechanism name.

getHmacAlgorithmName

protected String getHmacAlgorithmName()

Description copied from class: ScramSaslServer

The JCA name of the HMAC algorithm that corresponds to this mechanism's hash function, for example HmacSHA1.

Specified by:

getHmacAlgorithmName in class ScramSaslServer

Returns:

the HMAC algorithm name.

getDigestAlgorithmName

protected String getDigestAlgorithmName()

Description copied from class: ScramSaslServer

The JCA name of the message digest that corresponds to this mechanism's hash function, for example SHA-1. Used to compute H(ClientKey) when verifying the client proof.

Specified by:

getDigestAlgorithmName in class ScramSaslServer

Returns:

the message digest algorithm name.

getDefaultIterationCount

protected int getDefaultIterationCount()

Description copied from class: ScramSaslServer

The iteration count to advertise when no per-user value is available.

Specified by:

getDefaultIterationCount in class ScramSaslServer

Returns:

the default iteration count for this mechanism.

getNonExistentUserSecret

protected String getNonExistentUserSecret()

Description copied from class: ScramSaslServer

A server-side secret from which deterministic fake credentials are derived for non-existent users, so that authentication processing for non-existing users is indistinguishable from that of existing users.

Specified by:

getNonExistentUserSecret in class ScramSaslServer

Returns:

the server secret for this mechanism.

See Also:

• OF-3258: Guard against user enumeration in ScramSha1SaslServer