From 755e2c9d57f0517a73d16bfcaed93cc91969bdee Mon Sep 17 00:00:00 2001 From: Ralph Goers Date: Mon, 29 Nov 2021 22:28:07 -0700 Subject: [PATCH] Restrict LDAP access via JNDI --- log4j-core/pom.xml | 5 + .../log4j/core/appender/mom/JmsAppender.java | 31 ++++- .../logging/log4j/core/lookup/JndiLookup.java | 5 + .../logging/log4j/core/net/JndiManager.java | 106 ++++++++++++++- .../logging/log4j/core/util/NetUtils.java | 44 +++++++ .../log4j/core/lookup/JndiExploit.java | 36 +++++ .../log4j/core/lookup/JndiLdapLookupTest.java | 124 ++++++++++++++++++ .../src/test/resources/java-import.ldif | 4 + pom.xml | 6 + 9 files changed, 353 insertions(+), 8 deletions(-) create mode 100644 log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiExploit.java create mode 100644 log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiLdapLookupTest.java create mode 100644 log4j-core/src/test/resources/java-import.ldif diff --git a/log4j-core/pom.xml b/log4j-core/pom.xml index 5d24d6f..3afa014 100644 --- a/log4j-core/pom.xml +++ b/log4j-core/pom.xml @@ -332,6 +332,11 @@ HdrHistogram test + + org.zapodot + embedded-ldap-junit + test + diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/appender/mom/JmsAppender.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/appender/mom/JmsAppender.java index ddac666..f2190ca 100644 --- a/log4j-core/src/main/java/org/apache/logging/log4j/core/appender/mom/JmsAppender.java +++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/appender/mom/JmsAppender.java @@ -88,6 +88,12 @@ public class JmsAppender extends AbstractAppender { @PluginBuilderAttribute private boolean immediateFail; + @PluginBuilderAttribute + private String allowedLdapClasses; + + @PluginBuilderAttribute + private String allowedLdapHosts; + // Programmatic access only for now. private JmsManager jmsManager; @@ -100,8 +106,18 @@ public class JmsAppender extends AbstractAppender { JmsManager actualJmsManager = jmsManager; JmsManagerConfiguration configuration = null; if (actualJmsManager == null) { + Properties additionalProperties = null; + if (allowedLdapClasses != null || allowedLdapHosts != null) { + additionalProperties = new Properties(); + if (allowedLdapHosts != null) { + additionalProperties.put(JndiManager.ALLOWED_HOSTS, allowedLdapHosts); + } + if (allowedLdapClasses != null) { + additionalProperties.put(JndiManager.ALLOWED_CLASSES, allowedLdapClasses); + } + } final Properties jndiProperties = JndiManager.createProperties(factoryName, providerUrl, urlPkgPrefixes, - securityPrincipalName, securityCredentials, null); + securityPrincipalName, securityCredentials, additionalProperties); configuration = new JmsManagerConfiguration(jndiProperties, factoryBindingName, destinationBindingName, userName, password, false, reconnectIntervalMillis); actualJmsManager = AbstractManager.getManager(getName(), JmsManager.FACTORY, configuration); @@ -202,6 +218,16 @@ public class JmsAppender extends AbstractAppender { return this; } + public Builder setAllowedLdapClasses(final String allowedLdapClasses) { + this.allowedLdapClasses = allowedLdapClasses; + return this; + } + + public Builder setAllowedLdapHosts(final String allowedLdapHosts) { + this.allowedLdapHosts = allowedLdapHosts; + return this; + } + /** * Does not include the password. */ @@ -212,7 +238,8 @@ public class JmsAppender extends AbstractAppender { + ", securityCredentials=" + securityCredentials + ", factoryBindingName=" + factoryBindingName + ", destinationBindingName=" + destinationBindingName + ", username=" + userName + ", layout=" + getLayout() + ", filter=" + getFilter() + ", ignoreExceptions=" + isIgnoreExceptions() - + ", jmsManager=" + jmsManager + "]"; + + ", jmsManager=" + jmsManager + ", allowedLdapClasses=" + allowedLdapClasses + + ", allowedLdapHosts=" + allowedLdapHosts + "]"; } } diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/lookup/JndiLookup.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/lookup/JndiLookup.java index 30e65ad..e57d0be 100644 --- a/log4j-core/src/main/java/org/apache/logging/log4j/core/lookup/JndiLookup.java +++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/lookup/JndiLookup.java @@ -16,6 +16,11 @@ */ package org.apache.logging.log4j.core.lookup; +import java.net.MalformedURLException; +import java.net.URI; +import java.net.URISyntaxException; +import java.util.ArrayList; +import java.util.List; import java.util.Objects; import javax.naming.NamingException; diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/net/JndiManager.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/net/JndiManager.java index 2670857..8a0e68d 100644 --- a/log4j-core/src/main/java/org/apache/logging/log4j/core/net/JndiManager.java +++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/net/JndiManager.java @@ -17,31 +17,76 @@ package org.apache.logging.log4j.core.net; +import java.io.Serializable; +import java.net.URI; +import java.net.URISyntaxException; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.List; import java.util.Properties; import java.util.concurrent.TimeUnit; import javax.naming.Context; -import javax.naming.InitialContext; +import javax.naming.NameClassPair; +import javax.naming.NamingEnumeration; import javax.naming.NamingException; +import javax.naming.Referenceable; +import javax.naming.directory.Attribute; +import javax.naming.directory.Attributes; +import javax.naming.directory.DirContext; +import javax.naming.directory.InitialDirContext; import org.apache.logging.log4j.core.appender.AbstractManager; import org.apache.logging.log4j.core.appender.ManagerFactory; import org.apache.logging.log4j.core.util.JndiCloser; +import org.apache.logging.log4j.core.util.NetUtils; +import org.apache.logging.log4j.util.PropertiesUtil; /** - * Manages a JNDI {@link javax.naming.Context}. + * Manages a JNDI {@link javax.naming.directory.DirContext}. * * @since 2.1 */ public class JndiManager extends AbstractManager { + public static final String ALLOWED_HOSTS = "allowedLdapHosts"; + public static final String ALLOWED_CLASSES = "allowedLdapClasses"; + private static final JndiManagerFactory FACTORY = new JndiManagerFactory(); + private static final String PREFIX = "log4j2."; + private static final List permanentAllowedHosts = new ArrayList<>(); + private static final List permanentAllowedClasses = new ArrayList<>(); + private static final String LDAP = "ldap"; + private static final String SERIALIZED_DATA = "javaserializeddata"; + private static final String CLASS_NAME = "javaclassname"; + private static final String REFERENCE_ADDRESS = "javareferenceaddress"; + private static final String OBJECT_FACTORY = "javafactory"; + private final List allowedHosts; + private final List allowedClasses; + + static { + permanentAllowedHosts.addAll(NetUtils.getLocalIps()); + permanentAllowedClasses.add(Boolean.class.getName()); + permanentAllowedClasses.add(Byte.class.getName()); + permanentAllowedClasses.add(Character.class.getName()); + permanentAllowedClasses.add(Double.class.getName()); + permanentAllowedClasses.add(Float.class.getName()); + permanentAllowedClasses.add(Integer.class.getName()); + permanentAllowedClasses.add(Long.class.getName()); + permanentAllowedClasses.add(Number.class.getName()); + permanentAllowedClasses.add(Short.class.getName()); + permanentAllowedClasses.add(String.class.getName()); + } - private final Context context; - private JndiManager(final String name, final Context context) { + private final DirContext context; + + private JndiManager(final String name, final DirContext context, final List allowedHosts, + final List allowedClasses) { super(null, name); this.context = context; + this.allowedHosts = allowedHosts; + this.allowedClasses = allowedClasses; } /** @@ -168,7 +213,37 @@ public class JndiManager extends AbstractManager { * @throws NamingException if a naming exception is encountered */ @SuppressWarnings("unchecked") - public T lookup(final String name) throws NamingException { + public synchronized T lookup(final String name) throws NamingException { + try { + URI uri = new URI(name); + if (LDAP.equalsIgnoreCase(uri.getScheme())) { + if (!allowedHosts.contains(uri.getHost())) { + LOGGER.warn("Attempt to access ldap server not in allowed list"); + return null; + } + Attributes attributes = this.context.getAttributes(name); + if (attributes != null) { + Attribute classNameAttr = attributes.get(CLASS_NAME); + if (attributes.get(SERIALIZED_DATA) != null) { + if (classNameAttr != null) { + String className = classNameAttr.get().toString(); + if (!allowedClasses.contains(className)) { + LOGGER.warn("Deserialization of {} is not allowed", className); + return null; + } + } else { + LOGGER.warn("No class name provided for {}", name); + return null; + } + } else if (attributes.get(REFERENCE_ADDRESS) != null || attributes.get(OBJECT_FACTORY) != null){ + LOGGER.warn("Referenceable class is not allowed for {}", name); + return null; + } + } + } + } catch (URISyntaxException ex) { + // This is OK. + } return (T) this.context.lookup(name); } @@ -176,13 +251,32 @@ public class JndiManager extends AbstractManager { @Override public JndiManager createManager(final String name, final Properties data) { + String hosts = data != null ? data.getProperty(ALLOWED_HOSTS) : null; + String classes = data != null ? data.getProperty(ALLOWED_CLASSES) : null; + List allowedHosts = new ArrayList<>(); + List allowedClasses = new ArrayList<>(); + addAll(hosts, allowedHosts, permanentAllowedHosts, ALLOWED_HOSTS, data); + addAll(classes, allowedClasses, permanentAllowedClasses, ALLOWED_CLASSES, data); try { - return new JndiManager(name, new InitialContext(data)); + return new JndiManager(name, new InitialDirContext(data), allowedHosts, allowedClasses); } catch (final NamingException e) { LOGGER.error("Error creating JNDI InitialContext.", e); return null; } } + + private void addAll(String toSplit, List list, List permanentList, String propertyName, + Properties data) { + if (toSplit != null) { + list.addAll(Arrays.asList(toSplit.split("\\s*,\\s*"))); + data.remove(propertyName); + } + toSplit = PropertiesUtil.getProperties().getStringProperty(PREFIX + propertyName); + if (toSplit != null) { + list.addAll(Arrays.asList(toSplit.split("\\s*,\\s*"))); + } + list.addAll(permanentList); + } } @Override diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/util/NetUtils.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/util/NetUtils.java index e848822..b9a01ae 100644 --- a/log4j-core/src/main/java/org/apache/logging/log4j/core/util/NetUtils.java +++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/util/NetUtils.java @@ -17,6 +17,8 @@ package org.apache.logging.log4j.core.util; import java.io.File; +import java.net.Inet4Address; +import java.net.Inet6Address; import java.net.InetAddress; import java.net.MalformedURLException; import java.net.NetworkInterface; @@ -25,11 +27,14 @@ import java.net.URI; import java.net.URISyntaxException; import java.net.URL; import java.net.UnknownHostException; +import java.util.ArrayList; import java.util.Arrays; import java.util.Enumeration; +import java.util.List; import org.apache.logging.log4j.Logger; import org.apache.logging.log4j.status.StatusLogger; +import org.apache.logging.log4j.util.Strings; /** * Networking-related convenience methods. @@ -78,6 +83,45 @@ public final class NetUtils { } } + public static List getLocalIps() { + List localIps = new ArrayList<>(); + localIps.add("localhost"); + localIps.add("127.0.0.1"); + try { + final InetAddress addr = Inet4Address.getLocalHost(); + setHostName(addr, localIps); + } catch (final UnknownHostException ex) { + // Ignore this. + } + try { + final Enumeration interfaces = NetworkInterface.getNetworkInterfaces(); + if (interfaces != null) { + while (interfaces.hasMoreElements()) { + final NetworkInterface nic = interfaces.nextElement(); + final Enumeration addresses = nic.getInetAddresses(); + while (addresses.hasMoreElements()) { + final InetAddress address = addresses.nextElement(); + setHostName(address, localIps); + } + } + } + } catch (final SocketException se) { + // ignore. + } + return localIps; + } + + private static void setHostName(InetAddress address, List localIps) { + String[] parts = address.toString().split("\\s*/\\s*"); + if (parts.length > 0) { + for (String part : parts) { + if (Strings.isNotBlank(part) && !localIps.contains(part)) { + localIps.add(part); + } + } + } + } + /** * Returns the local network interface's MAC address if possible. The local network interface is defined here as * the {@link java.net.NetworkInterface} that is both up and not a loopback interface. diff --git a/log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiExploit.java b/log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiExploit.java new file mode 100644 index 0000000..7b0ae46 --- /dev/null +++ b/log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiExploit.java @@ -0,0 +1,36 @@ +/* + * 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.logging.log4j.core.lookup; + +import javax.naming.Context; +import javax.naming.Name; +import javax.naming.spi.ObjectFactory; +import java.util.Hashtable; + +import static org.junit.jupiter.api.Assertions.fail; + +/** + * Test LDAP object + */ +public class JndiExploit implements ObjectFactory { + @Override + public Object getObjectInstance(Object obj, Name name, Context nameCtx, Hashtable environment) + throws Exception { + fail("getObjectInstance must not be allowed"); + return null; + } +} diff --git a/log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiLdapLookupTest.java b/log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiLdapLookupTest.java new file mode 100644 index 0000000..73129f5 --- /dev/null +++ b/log4j-core/src/test/java/org/apache/logging/log4j/core/lookup/JndiLdapLookupTest.java @@ -0,0 +1,124 @@ +/* + * 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.logging.log4j.core.lookup; + +import javax.naming.Context; +import javax.naming.NamingException; +import javax.naming.Reference; +import javax.naming.Referenceable; +import javax.naming.StringRefAddr; + +import org.apache.logging.log4j.Level; +import org.apache.logging.log4j.message.SimpleMessage; +import org.junit.BeforeClass; +import org.junit.Rule; +import org.junit.Test; +import org.zapodot.junit.ldap.EmbeddedLdapRule; +import org.zapodot.junit.ldap.EmbeddedLdapRuleBuilder; + +import static org.junit.Assert.assertEquals; +import static org.junit.Assert.fail; + +/** + * JndiLookupTest + */ +public class JndiLdapLookupTest { + + private static final String LDAP_URL = "ldap://127.0.0.1:"; + private static final String RESOURCE = "JndiExploit"; + private static final String TEST_STRING = "TestString"; + private static final String TEST_MESSAGE = "TestMessage"; + private static final String LEVEL = "TestLevel"; + public static final String DOMAIN_DSN = "dc=apache,dc=org"; + + @Rule + public EmbeddedLdapRule embeddedLdapRule = EmbeddedLdapRuleBuilder.newInstance().usingDomainDsn(DOMAIN_DSN) + .importingLdifs("java-import.ldif").build(); + + @BeforeClass + public static void beforeClass() { + System.setProperty("log4j2.allowedLdapClasses", Level.class.getName()); + } + + @Test + public void testReferenceLookup() throws Exception { + int port = embeddedLdapRule.embeddedServerPort(); + Context context = embeddedLdapRule.context(); + context.bind( "cn=" + RESOURCE +"," + DOMAIN_DSN, new Fruit("Test Message")); + final StrLookup lookup = new JndiLookup(); + String result = lookup.lookup(LDAP_URL + port + "/" + "cn=" + RESOURCE + "," + DOMAIN_DSN); + if (result != null) { + fail("Lookup returned an object"); + } + } + + @Test + public void testSerializableLookup() throws Exception { + int port = embeddedLdapRule.embeddedServerPort(); + Context context = embeddedLdapRule.context(); + context.bind( "cn=" + TEST_STRING +"," + DOMAIN_DSN, "Test Message"); + final StrLookup lookup = new JndiLookup(); + String result = lookup.lookup(LDAP_URL + port + "/" + "cn=" + TEST_STRING + "," + DOMAIN_DSN); + if (result == null) { + fail("Lookup failed to return the test string"); + } + assertEquals("Incorrect message returned", "Test Message", result); + } + + @Test + public void testBadSerializableLookup() throws Exception { + int port = embeddedLdapRule.embeddedServerPort(); + Context context = embeddedLdapRule.context(); + context.bind( "cn=" + TEST_MESSAGE +"," + DOMAIN_DSN, new SimpleMessage("Test Message")); + final StrLookup lookup = new JndiLookup(); + String result = lookup.lookup(LDAP_URL + port + "/" + "cn=" + TEST_MESSAGE + "," + DOMAIN_DSN); + if (result != null) { + fail("Lookup returned an object"); + } + } + + @Test + public void testSpecialSerializableLookup() throws Exception { + int port = embeddedLdapRule.embeddedServerPort(); + Context context = embeddedLdapRule.context(); + context.bind( "cn=" + LEVEL +"," + DOMAIN_DSN, Level.ERROR); + final StrLookup lookup = new JndiLookup(); + String result = lookup.lookup(LDAP_URL + port + "/" + "cn=" + LEVEL + "," + DOMAIN_DSN); + if (result == null) { + fail("Lookup failed to return the level"); + } + assertEquals("Incorrect level returned", Level.ERROR.toString(), result); + } + + class Fruit implements Referenceable { + String fruit; + public Fruit(String f) { + fruit = f; + } + + public Reference getReference() throws NamingException { + + return new Reference(Fruit.class.getName(), new StringRefAddr("fruit", + fruit), JndiExploit.class.getName(), null); // factory location + } + + public String toString() { + return fruit; + } + } + +} diff --git a/log4j-core/src/test/resources/java-import.ldif b/log4j-core/src/test/resources/java-import.ldif new file mode 100644 index 0000000..35daf43 --- /dev/null +++ b/log4j-core/src/test/resources/java-import.ldif @@ -0,0 +1,4 @@ +dn: dc=apache,dc=org +objectClass: domain +objectClass: top +dc: apache \ No newline at end of file diff --git a/pom.xml b/pom.xml index d74175d..6fd99f1 100644 --- a/pom.xml +++ b/pom.xml @@ -868,6 +868,12 @@ 2.2.0 test + + + org.zapodot + embedded-ldap-junit + 0.8.1 + -- 2.27.0