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Elasticsearch Expanded Pack Plugin - Security
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0; you may not use this file except in compliance with the Elastic License
* 2.0.
*/
package org.elasticsearch.xpack.security.authc.jwt;
import com.nimbusds.jwt.JWTClaimsSet;
import com.nimbusds.jwt.SignedJWT;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.cache.Cache;
import org.elasticsearch.common.cache.CacheBuilder;
import org.elasticsearch.common.settings.RotatableSecret;
import org.elasticsearch.common.settings.SecureString;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.settings.SettingsException;
import org.elasticsearch.common.util.concurrent.ReleasableLock;
import org.elasticsearch.common.util.concurrent.ThreadContext;
import org.elasticsearch.core.Releasable;
import org.elasticsearch.core.TimeValue;
import org.elasticsearch.license.XPackLicenseState;
import org.elasticsearch.xpack.core.security.authc.AuthenticationResult;
import org.elasticsearch.xpack.core.security.authc.AuthenticationToken;
import org.elasticsearch.xpack.core.security.authc.Realm;
import org.elasticsearch.xpack.core.security.authc.RealmConfig;
import org.elasticsearch.xpack.core.security.authc.RealmSettings;
import org.elasticsearch.xpack.core.security.authc.jwt.JwtRealmSettings;
import org.elasticsearch.xpack.core.security.authc.support.CachingRealm;
import org.elasticsearch.xpack.core.security.authc.support.UserRoleMapper;
import org.elasticsearch.xpack.core.security.support.CacheIteratorHelper;
import org.elasticsearch.xpack.core.security.user.User;
import org.elasticsearch.xpack.core.ssl.SSLService;
import org.elasticsearch.xpack.security.authc.support.ClaimParser;
import org.elasticsearch.xpack.security.authc.support.DelegatedAuthorizationSupport;
import org.elasticsearch.xpack.security.support.ReloadableSecurityComponent;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import static java.lang.String.join;
import static org.elasticsearch.core.Strings.format;
import static org.elasticsearch.xpack.core.security.authc.jwt.JwtRealmSettings.CLIENT_AUTHENTICATION_SHARED_SECRET;
import static org.elasticsearch.xpack.core.security.authc.jwt.JwtRealmSettings.CLIENT_AUTH_SHARED_SECRET_ROTATION_GRACE_PERIOD;
/**
* JWT realms supports JWTs as bearer tokens for authenticating to Elasticsearch.
* For security, it is recommended to authenticate the client too.
*/
public class JwtRealm extends Realm implements CachingRealm, ReloadableSecurityComponent, Releasable {
private static final String LATEST_MALFORMED_JWT = "_latest_malformed_jwt";
private static final Logger logger = LogManager.getLogger(JwtRealm.class);
public static final String HEADER_END_USER_AUTHENTICATION = "Authorization";
public static final String HEADER_CLIENT_AUTHENTICATION = "ES-Client-Authentication";
public static final String HEADER_END_USER_AUTHENTICATION_SCHEME = "Bearer";
private final Cache jwtCache;
private final CacheIteratorHelper jwtCacheHelper;
private final UserRoleMapper userRoleMapper;
private final Boolean populateUserMetadata;
private final ClaimParser claimParserPrincipal;
private final ClaimParser claimParserGroups;
private final ClaimParser claimParserDn;
private final ClaimParser claimParserMail;
private final ClaimParser claimParserName;
private final JwtRealmSettings.ClientAuthenticationType clientAuthenticationType;
private final RotatableSecret clientAuthenticationSharedSecret;
private final JwtAuthenticator jwtAuthenticator;
private final TimeValue allowedClockSkew;
DelegatedAuthorizationSupport delegatedAuthorizationSupport = null;
public JwtRealm(final RealmConfig realmConfig, final SSLService sslService, final UserRoleMapper userRoleMapper)
throws SettingsException {
super(realmConfig);
this.userRoleMapper = userRoleMapper;
this.userRoleMapper.clearRealmCacheOnChange(this);
this.allowedClockSkew = realmConfig.getSetting(JwtRealmSettings.ALLOWED_CLOCK_SKEW);
this.populateUserMetadata = realmConfig.getSetting(JwtRealmSettings.POPULATE_USER_METADATA);
this.clientAuthenticationType = realmConfig.getSetting(JwtRealmSettings.CLIENT_AUTHENTICATION_TYPE);
this.clientAuthenticationSharedSecret = new RotatableSecret(
realmConfig.getSetting(JwtRealmSettings.CLIENT_AUTHENTICATION_SHARED_SECRET)
);
// Validate Client Authentication settings. Throw SettingsException there was a problem.
JwtUtil.validateClientAuthenticationSettings(
RealmSettings.getFullSettingKey(realmConfig, JwtRealmSettings.CLIENT_AUTHENTICATION_TYPE),
this.clientAuthenticationType,
RealmSettings.getFullSettingKey(realmConfig, JwtRealmSettings.CLIENT_AUTHENTICATION_SHARED_SECRET),
this.clientAuthenticationSharedSecret
);
final TimeValue jwtCacheTtl = realmConfig.getSetting(JwtRealmSettings.JWT_CACHE_TTL);
final int jwtCacheSize = realmConfig.getSetting(JwtRealmSettings.JWT_CACHE_SIZE);
if (jwtCacheTtl.getNanos() > 0 && jwtCacheSize > 0) {
this.jwtCache = CacheBuilder.builder()
.setExpireAfterWrite(jwtCacheTtl)
.setMaximumWeight(jwtCacheSize)
.build();
this.jwtCacheHelper = new CacheIteratorHelper<>(this.jwtCache);
} else {
// TODO: log invalid cache settings
this.jwtCache = null;
this.jwtCacheHelper = null;
}
jwtAuthenticator = new JwtAuthenticator(realmConfig, sslService, this::expireAll);
final Map fallbackClaimNames = jwtAuthenticator.getFallbackClaimNames();
this.claimParserPrincipal = ClaimParser.forSetting(
logger,
JwtRealmSettings.CLAIMS_PRINCIPAL,
fallbackClaimNames,
realmConfig,
true
);
this.claimParserGroups = ClaimParser.forSetting(logger, JwtRealmSettings.CLAIMS_GROUPS, fallbackClaimNames, realmConfig, false);
this.claimParserDn = ClaimParser.forSetting(logger, JwtRealmSettings.CLAIMS_DN, fallbackClaimNames, realmConfig, false);
this.claimParserMail = ClaimParser.forSetting(logger, JwtRealmSettings.CLAIMS_MAIL, fallbackClaimNames, realmConfig, false);
this.claimParserName = ClaimParser.forSetting(logger, JwtRealmSettings.CLAIMS_NAME, fallbackClaimNames, realmConfig, false);
}
/**
* If X-pack licensing allows it, initialize delegated authorization support.
* @param allRealms List of all realms containing authorization realms for this JWT realm.
* @param xpackLicenseState X-pack license state.
*/
@Override
public void initialize(final Iterable allRealms, final XPackLicenseState xpackLicenseState) {
if (delegatedAuthorizationSupport != null) {
throw new IllegalStateException("Realm " + name() + " has already been initialized");
}
// extract list of realms referenced by config.settings() value for DelegatedAuthorizationSettings.ROLES_REALMS
delegatedAuthorizationSupport = new DelegatedAuthorizationSupport(allRealms, config, xpackLicenseState);
}
/**
* Clean up JWT cache (if enabled).
* Clean up HTTPS client cache (if enabled).
*/
@Override
public void close() {
jwtAuthenticator.close();
}
@Override
public void lookupUser(final String username, final ActionListener listener) {
ensureInitialized();
listener.onResponse(null); // Run-As and Delegated Authorization lookups are not supported by JWT realms
}
@Override
public void expire(final String username) {
ensureInitialized();
if (isCacheEnabled()) {
logger.trace("Expiring JWT cache entries for realm [{}] principal=[{}]", name(), username);
jwtCacheHelper.removeValuesIf(expiringUser -> expiringUser.user.principal().equals(username));
logger.trace("Expired JWT cache entries for realm [{}] principal=[{}]", name(), username);
}
}
@Override
public void expireAll() {
ensureInitialized();
invalidateJwtCache();
}
@Override
public AuthenticationToken token(final ThreadContext threadContext) {
ensureInitialized();
final SecureString userCredentials = JwtUtil.getHeaderValue(
threadContext,
JwtRealm.HEADER_END_USER_AUTHENTICATION,
JwtRealm.HEADER_END_USER_AUTHENTICATION_SCHEME,
false
);
SignedJWT signedJWT = parseSignedJWT(userCredentials, threadContext);
if (signedJWT == null) {
// this is not a valid JWT for ES realms, but custom realms can also consume the Bearer credentials scheme in their own format
return null;
}
final SecureString clientCredentials = JwtUtil.getHeaderValue(
threadContext,
JwtRealm.HEADER_CLIENT_AUTHENTICATION,
JwtRealmSettings.HEADER_SHARED_SECRET_AUTHENTICATION_SCHEME,
true
);
return new JwtAuthenticationToken(signedJWT, JwtUtil.sha256(userCredentials), clientCredentials);
}
@Override
public boolean supports(final AuthenticationToken jwtAuthenticationToken) {
return (jwtAuthenticationToken instanceof JwtAuthenticationToken);
}
@Override
public void authenticate(final AuthenticationToken authenticationToken, final ActionListener> listener) {
ensureInitialized();
if (authenticationToken instanceof JwtAuthenticationToken jwtAuthenticationToken) {
final String tokenPrincipal = jwtAuthenticationToken.principal();
// Authenticate client: If client authc off, fall through. Otherwise, only fall through if secret matched.
final SecureString clientSecret = jwtAuthenticationToken.getClientAuthenticationSharedSecret();
try {
JwtUtil.validateClientAuthentication(
clientAuthenticationType,
clientAuthenticationSharedSecret,
clientSecret,
tokenPrincipal
);
logger.trace("Realm [{}] client authentication succeeded for token=[{}].", name(), tokenPrincipal);
} catch (Exception e) {
final String msg = "Realm [" + name() + "] client authentication failed for token=[" + tokenPrincipal + "].";
logger.debug(msg, e);
listener.onResponse(AuthenticationResult.unsuccessful(msg, e));
return; // FAILED (secret is missing or mismatched)
}
final BytesArray jwtCacheKey = isCacheEnabled()
? new BytesArray(new BytesRef(jwtAuthenticationToken.getUserCredentialsHash()), true)
: null;
if (jwtCacheKey != null) {
final User cachedUser = tryAuthenticateWithCache(tokenPrincipal, jwtCacheKey);
if (cachedUser != null) {
if (delegatedAuthorizationSupport.hasDelegation()) {
delegatedAuthorizationSupport.resolve(cachedUser.principal(), listener);
} else {
listener.onResponse(AuthenticationResult.success(cachedUser));
}
return;
}
}
// Validate JWT: Extract JWT and claims set, and validate JWT.
jwtAuthenticator.authenticate(jwtAuthenticationToken, ActionListener.wrap(claimsSet -> {
if (logger.isDebugEnabled()) {
logger.debug(
"Realm [{}] JWT validation success for token=[{}] with header [{}] and claimSet [{}]",
name(),
tokenPrincipal,
jwtAuthenticationToken.getSignedJWT().getHeader(),
jwtAuthenticationToken.getJWTClaimsSet()
);
}
processValidatedJwt(tokenPrincipal, jwtCacheKey, claimsSet, listener);
}, ex -> {
final String msg = "Realm ["
+ name()
+ "] JWT validation failed for token=["
+ tokenPrincipal
+ "] with header ["
+ jwtAuthenticationToken.getSignedJWT().getHeader()
+ "] and claimSet ["
+ jwtAuthenticationToken.getJWTClaimsSet()
+ "]";
if (logger.isTraceEnabled()) {
logger.trace(msg, ex);
} else {
logger.debug(msg + " Cause: " + ex.getMessage()); // only log the stack trace at trace level
}
// TODO: No point to continue to another realm if failure is ParseException
listener.onResponse(AuthenticationResult.unsuccessful(msg, ex));
}));
} else {
assert false : "should not happen";
final String className = (authenticationToken == null) ? "null" : authenticationToken.getClass().getCanonicalName();
final String msg = "Realm [" + name() + "] does not support AuthenticationToken [" + className + "].";
logger.trace(msg);
listener.onResponse(AuthenticationResult.unsuccessful(msg, null));
}
}
void ensureInitialized() {
if (delegatedAuthorizationSupport == null) {
throw new IllegalStateException("Realm has not been initialized");
}
}
// Package private for testing
RealmConfig getConfig() {
return config;
}
// Package private for testing
JwtAuthenticator getJwtAuthenticator() {
return jwtAuthenticator;
}
private User tryAuthenticateWithCache(final String tokenPrincipal, final BytesArray jwtCacheKey) {
final ExpiringUser expiringUser = jwtCache.get(jwtCacheKey);
if (expiringUser == null) {
logger.trace("Realm [" + name() + "] JWT cache miss token=[" + tokenPrincipal + "] key=[" + jwtCacheKey + "].");
} else {
final User user = expiringUser.user;
final Date exp = expiringUser.exp; // claimsSet.getExpirationTime().getTime() + allowedClockSkew.getMillis()
final String principal = user.principal();
final Date now = new Date();
final boolean cacheEntryNotExpired = now.getTime() < exp.getTime();
logger.trace(
"Realm [{}] JWT cache {} token=[{}] key=[{}] principal=[{}] exp=[{}] now=[{}].",
name(),
cacheEntryNotExpired ? "hit" : "exp",
tokenPrincipal,
jwtCacheKey,
principal,
exp,
now
);
if (cacheEntryNotExpired) {
return user;
}
// TODO: evict the entry
}
return null;
}
// package private for testing
void processValidatedJwt(
String tokenPrincipal,
BytesArray jwtCacheKey,
JWTClaimsSet claimsSet,
ActionListener> listener
) {
// At this point, JWT is validated. Parse the JWT claims using realm settings.
final String principal = claimParserPrincipal.getClaimValue(claimsSet);
if (Strings.hasText(principal) == false) {
final String msg = "Realm ["
+ name()
+ "] no principal for token=["
+ tokenPrincipal
+ "] parser=["
+ claimParserPrincipal
+ "] claims=["
+ claimsSet
+ "].";
logger.debug(msg);
listener.onResponse(AuthenticationResult.unsuccessful(msg, null));
return;
}
// Roles listener: Log roles from delegated authz lookup or role mapping, and cache User if JWT cache is enabled.
final ActionListener> logAndCacheListener = ActionListener.wrap(result -> {
if (result.isAuthenticated()) {
final User user = result.getValue();
logger.trace(
() -> format("Realm [%s] roles resolved [%s] for principal=[%s].", name(), join(",", user.roles()), principal)
);
if (isCacheEnabled()) {
try (ReleasableLock ignored = jwtCacheHelper.acquireUpdateLock()) {
final long expWallClockMillis = claimsSet.getExpirationTime().getTime() + allowedClockSkew.getMillis();
jwtCache.put(jwtCacheKey, new ExpiringUser(result.getValue(), new Date(expWallClockMillis)));
}
}
}
listener.onResponse(result);
}, listener::onFailure);
// Delegated role lookup or Role mapping: Use the above listener to log roles and cache User.
if (delegatedAuthorizationSupport.hasDelegation()) {
delegatedAuthorizationSupport.resolve(principal, logAndCacheListener);
return;
}
// User metadata: If enabled, extract metadata from JWT claims set. Use it in UserRoleMapper.UserData and User constructors.
final Map userMetadata = buildUserMetadata(claimsSet);
// Role resolution: Handle role mapping in JWT Realm.
final List groups = claimParserGroups.getClaimValues(claimsSet);
final String dn = claimParserDn.getClaimValue(claimsSet);
final String mail = claimParserMail.getClaimValue(claimsSet);
final String name = claimParserName.getClaimValue(claimsSet);
final UserRoleMapper.UserData userData = new UserRoleMapper.UserData(principal, dn, groups, userMetadata, config);
userRoleMapper.resolveRoles(userData, ActionListener.wrap(rolesSet -> {
final User user = new User(principal, rolesSet.toArray(Strings.EMPTY_ARRAY), name, mail, userData.getMetadata(), true);
logAndCacheListener.onResponse(AuthenticationResult.success(user));
}, logAndCacheListener::onFailure));
}
@Override
public void usageStats(final ActionListener> listener) {
ensureInitialized();
super.usageStats(ActionListener.wrap(stats -> {
stats.put("jwt.cache", Collections.singletonMap("size", isCacheEnabled() ? jwtCache.count() : -1));
listener.onResponse(stats);
}, listener::onFailure));
}
@Override
public void reload(Settings settings) {
final SecureString newClientSharedSecret = CLIENT_AUTHENTICATION_SHARED_SECRET.getConcreteSettingForNamespace(
this.realmRef().getName()
).get(settings);
JwtUtil.validateClientAuthenticationSettings(
RealmSettings.getFullSettingKey(this.config, JwtRealmSettings.CLIENT_AUTHENTICATION_TYPE),
this.clientAuthenticationType,
RealmSettings.getFullSettingKey(this.config, JwtRealmSettings.CLIENT_AUTHENTICATION_SHARED_SECRET),
new RotatableSecret(newClientSharedSecret)
);
this.clientAuthenticationSharedSecret.rotate(
newClientSharedSecret,
config.getSetting(CLIENT_AUTH_SHARED_SECRET_ROTATION_GRACE_PERIOD)
);
}
/**
* Clean up JWT cache (if enabled).
*/
private void invalidateJwtCache() {
if (isCacheEnabled()) {
try {
logger.trace("Invalidating JWT cache for realm [{}]", name());
try (ReleasableLock ignored = jwtCacheHelper.acquireForIterator()) {
jwtCache.invalidateAll();
}
logger.debug("Invalidated JWT cache for realm [{}]", name());
} catch (Exception e) {
// TODO: We should let the error bubble up instead of swallowing it
logger.warn("Exception invalidating JWT cache for realm [" + name() + "]", e);
}
}
}
private boolean isCacheEnabled() {
return jwtCache != null && jwtCacheHelper != null;
}
// package private for testing
Cache getJwtCache() {
return jwtCache;
}
/**
* Format and filter JWT contents as user metadata.
* @param claimsSet Claims are supported. Claim keys are prefixed by "jwt_claim_".
* @return Map of formatted and filtered values to be used as user metadata.
*/
private Map buildUserMetadata(JWTClaimsSet claimsSet) {
final HashMap metadata = new HashMap<>();
metadata.put("jwt_token_type", jwtAuthenticator.getTokenType().value());
if (populateUserMetadata) {
claimsSet.getClaims()
.entrySet()
.stream()
.filter(entry -> isAllowedTypeForClaim(entry.getValue()))
.forEach(entry -> metadata.put("jwt_claim_" + entry.getKey(), entry.getValue()));
}
return Map.copyOf(metadata);
}
/**
* Parses a {@link SignedJWT} from the provided {@param token}.
* This internally, for the local thread, remembers the last **malformed** token parsed,
* in order to avoid attempting to parse the same token multiple consecutive times (by different JWT realms in the chain).
*/
private SignedJWT parseSignedJWT(SecureString token, ThreadContext threadContext) {
if (Objects.equals(token, threadContext.getTransient(LATEST_MALFORMED_JWT))) {
// already tried to parse this token and it didn't work
return null;
}
SignedJWT signedJWT = JwtUtil.parseSignedJWT(token);
if (signedJWT == null) {
// this is a malformed JWT, update the latest malformed token reference
threadContext.putTransient(LATEST_MALFORMED_JWT, token);
}
return signedJWT;
}
/**
* JWTClaimsSet values are only allowed to be String, Boolean, Number, or Collection.
* Collections are only allowed to contain String, Boolean, or Number.
* Collections recursion is not allowed.
* Maps are not allowed.
* Nulls are not allowed.
* @param value Claim value object.
* @return True if the claim value is allowed, otherwise false.
*/
private static boolean isAllowedTypeForClaim(final Object value) {
return (value instanceof String
|| value instanceof Boolean
|| value instanceof Number
|| (value instanceof Collection
&& ((Collection) value).stream().allMatch(e -> e instanceof String || e instanceof Boolean || e instanceof Number)));
}
// Cached authenticated users, and adjusted JWT expiration date (=exp+skew) for checking if the JWT expired before the cache entry
record ExpiringUser(User user, Date exp) {
ExpiringUser {
Objects.requireNonNull(user, "User must not be null");
Objects.requireNonNull(exp, "Expiration date must not be null");
}
}
}
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