Github user EronWright commented on a diff in the pull request:
https://github.com/apache/flink/pull/3057#discussion_r95283348
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/security/modules/JaasModule.java
---
@@ -0,0 +1,147 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.flink.runtime.security.modules;
+
+import org.apache.flink.annotation.Internal;
+import org.apache.flink.runtime.security.DynamicConfiguration;
+import org.apache.flink.runtime.security.KerberosUtils;
+import org.apache.flink.runtime.security.SecurityUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.security.auth.login.AppConfigurationEntry;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+
+/**
+ * Responsible for installing a process-wide JAAS configuration.
+ * <p>
+ * The installed configuration combines login modules based on:
+ * - the user-supplied JAAS configuration file, if any
+ * - a Kerberos keytab, if configured
+ * - any cached Kerberos credentials from the current environment
+ * <p>
+ * The module also installs a default JAAS config file (if necessary) for
+ * compatibility with ZK and Kafka. Note that the JRE actually draws on
numerous file locations.
+ * See:
https://docs.oracle.com/javase/7/docs/jre/api/security/jaas/spec/com/sun/security/auth/login/ConfigFile.html
+ * See:
https://github.com/apache/kafka/blob/0.9.0/clients/src/main/java/org/apache/kafka/common/security/kerberos/Login.java#L289
+ */
+@Internal
+public class JaasModule implements SecurityModule {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(JaasModule.class);
+
+ static final String JAVA_SECURITY_AUTH_LOGIN_CONFIG =
"java.security.auth.login.config";
+
+ static final String JAAS_CONF_RESOURCE_NAME = "flink-jaas.conf";
+
+ private String priorConfigFile;
+ private javax.security.auth.login.Configuration priorConfig;
+
+ private DynamicConfiguration currentConfig;
+
+ @Override
+ public void install(SecurityUtils.SecurityConfiguration securityConfig)
{
+
+ // ensure that a config file is always defined, for
compatibility with
+ // ZK and Kafka which check for the system property and
existence of the file
+ priorConfigFile =
System.getProperty(JAVA_SECURITY_AUTH_LOGIN_CONFIG, null);
+ if (priorConfigFile == null) {
+ File configFile = generateDefaultConfigFile();
+ System.setProperty(JAVA_SECURITY_AUTH_LOGIN_CONFIG,
configFile.getAbsolutePath());
+ }
+
+ // read the JAAS configuration file
+ priorConfig =
javax.security.auth.login.Configuration.getConfiguration();
+
+ // construct a dynamic JAAS configuration
+ currentConfig = new DynamicConfiguration(priorConfig);
+
+ // wire up the configured JAAS login contexts to use the krb5
entries
+ AppConfigurationEntry[] krb5Entries =
getAppConfigurationEntries(securityConfig);
+ if(krb5Entries != null) {
+ for (String app :
securityConfig.getLoginContextNames()) {
+ currentConfig.addAppConfigurationEntry(app,
krb5Entries);
+ }
+ }
+
+
javax.security.auth.login.Configuration.setConfiguration(currentConfig);
+ }
+
+ @Override
+ public void uninstall() {
+ if(priorConfigFile != null) {
+ System.setProperty(JAVA_SECURITY_AUTH_LOGIN_CONFIG,
priorConfigFile);
+ } else {
+ System.clearProperty(JAVA_SECURITY_AUTH_LOGIN_CONFIG);
+ }
+
javax.security.auth.login.Configuration.setConfiguration(priorConfig);
+ }
+
+ public DynamicConfiguration getCurrentConfiguration() {
+ return currentConfig;
+ }
+
+ private static AppConfigurationEntry[]
getAppConfigurationEntries(SecurityUtils.SecurityConfiguration securityConfig) {
+
+ AppConfigurationEntry userKerberosAce = null;
+ if (securityConfig.useTicketCache()) {
+ userKerberosAce = KerberosUtils.ticketCacheEntry();
+ }
+ AppConfigurationEntry keytabKerberosAce = null;
+ if (securityConfig.getKeytab() != null) {
+ keytabKerberosAce =
KerberosUtils.keytabEntry(securityConfig.getKeytab(),
securityConfig.getPrincipal());
+ }
+
+ AppConfigurationEntry[] appConfigurationEntry;
+ if (userKerberosAce != null && keytabKerberosAce != null) {
+ appConfigurationEntry = new
AppConfigurationEntry[]{keytabKerberosAce, userKerberosAce};
+ } else if (keytabKerberosAce != null) {
+ appConfigurationEntry = new
AppConfigurationEntry[]{keytabKerberosAce};
+ } else if (userKerberosAce != null) {
+ appConfigurationEntry = new
AppConfigurationEntry[]{userKerberosAce};
+ } else {
+ return null;
+ }
+
+ return appConfigurationEntry;
+ }
+
+ /**
+ * Generate the default JAAS config file.
+ */
+ private static File generateDefaultConfigFile() {
+ // load Jaas config file to initialize SASL
+ final File jaasConfFile;
+ try {
+ Path jaasConfPath = Files.createTempFile("jaas-",
".conf");
+ try (InputStream resourceStream =
JaasModule.class.getClassLoader().getResourceAsStream(JAAS_CONF_RESOURCE_NAME))
{
+ Files.copy(resourceStream, jaasConfPath,
StandardCopyOption.REPLACE_EXISTING);
+ }
+ jaasConfFile = jaasConfPath.toFile();
+ jaasConfFile.deleteOnExit();
+ } catch (IOException e) {
+ throw new RuntimeException("unable to generate a JAAS
configuration file", e);
--- End diff --
In this case, I do consider a failure to generate the default config a
programming error; it simply extracts an in-built resource as a temp file. I
definitely agree with your general point.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
