wolfSSL JSSE Provider and JNI Wrapper

This package provides Java support for the wolfSSL embedded SSL/TLS library, giving applications support for SSL/TLS up to the current TLS 1.3 protocol level. It contains both a wolfSSL JSSE (Java Secure Socket Extension) provider, called wolfJSSE, and a thin JNI-based interface that wraps the native C library.

wolfSSL also provides a JCE (Java Cryptography Extension) provider that wraps native wolfCrypt. This can be found in a separate repository, located here.

Why use wolfJSSE?

This interface gives Java applications access to all the benefits of using wolfSSL, including current SSL/TLS standards up to TLS 1.3, FIPS 140-2 and 140-3 support, performance optimizations, hardware cryptography support, commercial support, and more!

User Manual

The wolfSSL JNI/JSSE Manual is available on the wolfSSL website: wolfSSL JNI Manual.

For additional build instructions and more detailed comments, please reference the manual.

Building

wolfJSSE currently supports compilation on the following platforms:

• Linux/Unix
• Mac OSX
• Windows (Visual Studio)
• Android Studio
• Android AOSP

To build wolfJSSE on Windows using Visual Studio, please reference the Windows README.md.

Building Native wolfSSL (Dependency)

To compile the wolfSSL JNI wrapper and JSSE provider, first the native (C) wolfSSL library must be compiled and installed.

To build wolfJSSE in Linux/Unix environments, first download, compile, and install wolfSSL. wolfSSL can be downloaded from the wolfSSL download page or cloned from GitHub.

$ unzip wolfssl-X.X.X.zip
$ cd wolfssl-X.X.X
$ ./configure --enable-jni
$ make check
$ sudo make install

If building a wolfSSL FIPS or FIPS Ready release bundle, additional configure options may be required. Reference the wolfSSL Manual and build documentation for exact build instructions.

Building with ant

wolfSSL JNI/JSSE's ant build is the most stable and well-tested. Newer support for building with Maven has also been added. See section below for instructions on building with Maven.

Note 1) The java.sh script uses a common location for the Java install location. If your Java install location is different, this could lead to an error when running java.sh. In this case, you should modify java.sh to match your environment.

Build targets for ant are :

• ant build (ant) (only builds the jar necessary for an app to use)
• ant test (builds the jar and tests then runs the tests, requires JUNIT setup)
• ant examples (builds the jar and example cases)
• ant clean (cleans all Java artifacts)
• ant cleanjni (cleans native artifacts)

To build wolfJSSE:

$ cd wolfssljni
$ ./java.sh
$ ant
$ export JUNIT_HOME=/path/to/junit/jars
$ ant test

To compile and run the examples, use the ant examples target:

$ ant examples

Then, run the examples from the root directory using the provided wrapper scripts:

$ ./examples/provider/ServerJSSE.sh
$ ./examples/provider/ClientJSSE.sh

Building with Maven

wolfJSSE supports building and packaging with Maven, for those projects that are already set up to use and consume Maven packages.

wolfJSSE's Maven build configuration is defined in the included pom.xml.

First, compile the native JNI shared library (libwolfssljni.so/dylib) same as above. This will create the native JNI shared library under the ./lib directory:

$ ./java.sh

Compile the Java sources, where Maven will place the compiled .class files under the ./target/classes directory:

$ mvn compile

Compile and run JUnit tests using:

$ mvn test

Package up the wolfSSL JNI/JSSE JAR file using the following command. This will run the JUnit tests then create a .jar file located under the ./target directory, similar to target/wolfssl-jsse-X.X.X-SNAPSHOT.jar:

$ mvn package

To build the Javadoc API reference for wolfSSL JNI/JSSE run the following. This will generate Javadoc HTML under the ./docs/apidocs directory:

$ mvn javadoc:javadoc

To install the wolfSSL JNI/JSSE JAR file, run the following. This will install the JAR into the local Maven repository:

$ mvn install

The local Maven repository installation location will be similar to:

~/.m2/repository/com/wolfssl/wolfssl-jsse/X.X.X-SNAPSHOT/wolfssl-jsse-X.X.X-SNAPSHOT.jar

The wolfSSL JNI shared library (libwolfssljni.so/dylib) created with the java.sh script will need to be "installed" by being placed on your native library search path. For example, copied into /usr/local/lib, /usr/lib, or other location. Alternatively, append the ./libs directory to your native library search path by exporting LD_LIBRARY_PATH (Linux) or DYLD_LIBRARY_PATH (OSX):

$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/wolfssljni/lib

After wolfSSL JNI/JSSE has been installed into the local Maven repository, an application can include this as a dependency in the application's pom.xml file, similar to:

<project ...>
    ...
    <dependencies>
        <dependency>
            <groupId>com.wolfssl</groupId>
            <artifactId>wolfssl-jsse</artifactId>
            <version>1.14.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
    ...
</project>

Examples

Examples of using wolfssljni can be found in the ./examples subdirectory. See examples/README.md for more details.

Examples of using the wolfJSSE provider can be found in the ./examples/provider subdirectory. See examples/provider/README.md for more details.

Example certificates and keys are included in this bundle. These should only be used for testing and prototyping. Example certificates included here are duplicates of the ones that ship with standard wolfSSL. If needed, certificates can be easily updated from an existing wolfSSL directory by using the script examples/certs/update-certs.sh. This should be run from the examples/certs directory and given one argument which is the path to a wolfSSL certs directory.

Debugging

wolfSSL JNI/JSSE supports several System properties for enabling debug logging. The table below describes the currently-supported debug properties and what each enables.

System Property	Default	To Enable	Description
wolfssl.debug	"false"	"true"	Enables native wolfSSL debug logging
wolfjsse.debug	"false"	"true	Enables wolfJSSE debug logging
wolfjsse.debugFormat		"JSON"	Switches debug output format
wolfsslengine.debug	"false"	"true"	Enables SSLEngine debug logging
wolfsslengine.io.debug	"false"	"true"	Enables SSLEngine I/O bytes log

Native wolfSSL logging (wolfssl.debug) will only output messages if native wolfSSL has been configured with --enable-debug.

These System properties can be defined at runtime, ie:

java -Dwolfjsse.debug=true App

Or these system properties can also be set programmatically at runtime, ie:

System.setProperty("wolfjsse.debug", "true");
System.setProperty("wolfsslengine.debug", "true);

JDK debug logging can be enabled using the -Djavax.net.debug=all option.

JSON Log Message Format

Debug messages can be output in JSON format for consumption by tools such as DataDog. Setting the following System property to "JSON" will cause all debug messages to print in JSON instead of the default text output:

System.setProperty("wolfjsse.debugFormat", "JSON");

This can also be specified at runtime on the command line like so:

-Dwolfjsse.debug=true -Dwolfjsse.debugFormat=JSON

Debug messages will look similar to the following when output in JSON format:

{
    "@timestamp": "2024-04-05 11:13:07.193",
    "level": "INFO",
    "logger_name": "wolfJSSE",
    "message": "[ WolfSSLTrustManager] entered engineInit()",
    "thread_name": "main",:
    "thread_id": "1"
}

Building for Android

wolfSSL JNI and JSSE can be built and used on the Android platform, either at the application-level or installed inside a modified version of the Android AOSP at the system-level.

Android Application Level Usage

An example Android Studio application is included in this package, to show users how they could include the wolfSSL native and wolfSSL JNI/JSSE sources in an Android Studio application. For more details, see the Android Studio project and README.md located in the ./IDE/Android directory.

Using wolfJSSE at the application level will allow developers to register wolfJSSE as a Security provider at the application scope. The application can use the Java Security API for SSL/TLS operations which will then use the underlying wolfJSSE provider (and subsequently native wolfSSL).

Applications can register the wolfJSSE provider using:

import com.wolfssl.provider.jsse.WolfSSLProvider;
...
Security.addProvider(new WolfSSLProvider());

To instead insert the WolfSSLProvider as the top priority provider, or at a specified index (note: indexing starts at 1):

import com.wolfssl.provider.jsse.WolfSSLProvider;
...
Security.insertProviderAt(new WolfSSLProvider(), 1);

There are also additional Android examples using wolfSSL JNI in the wolfssl-examples repository.

Android AOSP System Level Installation

wolfJSSE can be installed inside an Android AOSP build and registered at the OS/system level. This will allow wolfJSSE to be registered as the highest priority JSSE provider on Android, thus allowing any application using the Java Security API to automatically use wolfJSSE and wolfSSL.

For details on how to install wolfJSSE in Android AOSP, see the README located in the ./platform/android_aosp directory.

Additional instructions can be found on the wolfSSL.com website: Installing a JSSE Provider in Android OSP.

Behavior and Functionality Notes

JSSE Class Implementation Support

wolfJSSE extends or implements the following JSSE classes:

• javax.net.ssl.SSLContextSpi
  • SSL, TLS, DEFAULT, TLSv1, TLSv1.1, TLSv1.2, TLSv1.3
• javax.net.ssl.KeyManagerFactorySpi
  • PKIX, X509, SunX509
• javax.net.ssl.TrustManagerFactorySpi
  • PKIX, X509, SunX509
• javax.net.ssl.SSLEngine
• javax.net.ssl.SSLSession / ExtendedSSLSession
• javax.net.ssl.X509KeyManager / X509ExtendedKeyManager
• javax.net.ssl.X509TrustManager / X509ExtendedTrustManager
• javax.net.ssl.SSLServerSocket
• javax.net.ssl.SSLServerSocketFactory
• javax.net.ssl.SSLSocket
• javax.net.ssl.SSLSocketFactory
• javax.net.ssl.SSLSessionContext
• java.security.cert.X509Certificate
• javax.security.cert.X509Certificate

Secure Renegotiation Support

wolfSSL JNI and JSSE provider wrap native wolfSSL APIs to enable and conduct secure renegotiation. For secure renegotiation functionality to be available in wolfSSL JNI, and enabled for use in wolfJSSE, native wolfSSL must be compiled with secure renegotiation support:

$ ./configure --enable-secure-renegotiation

Or by defining -DHAVE_SECURE_RENEGOTIATION.

Native File Descriptor Events

wolfSSL JNI/JSSE internally makes several calls that operate on native file descriptors inside Java Socket objects. These native file descriptors are watched for read and write events with either select() or poll().

By default poll() will be used, unless WOLFJNI_USE_IO_SELECT is defined or added to CFLAGS when compiling the native JNI sources (see java.sh). Windows builds will also default to using select() since poll() is not available there.

wolfSSL JNI/JSSE does not select/poll on a large number of file descriptors (typically just one). Although if used in applications that make lots of connections, when using select() the FD_ISSET and other related macros result in undefined behavior when the file descriptor number is larger than FD_SETSIZE (defaults to 1024 on most systems). For this reason, poll() is used as the default descriptor monitoring function.

Security Property Support

wolfJSSE allows for some customization through the java.security file and use of Security properties.

Support is included for the following pre-existing Java Security properties.

keystore.type (String) - Specifies the default KeyStore type. This defaults to JKS, but could be set to something else if desired.

jdk.tls.disabledAlgorithms (String) - Can be used to disable algorithms, TLS protocol versions, and key lengths, among other things. This should be a comma-delimited String. wolfJSSE includes partial support for this property, with supported items including disabling SSL/TLS protocol versions and setting minimum RSA/ECC/DH key sizes. An example of potential use:

jdk.tls.disabledAlgorithms=SSLv3, TLSv1.1, DH keySize < 1024, EC keySize < 224, RSA keySize < 1024

The following custom wolfJSSE-specific Security property settings are supported. These can be placed into the java.security file and will be parsed and used by wolfJSSE.

wolfjsse.enabledCipherSuites (String) - Allows restriction of the enabled cipher suiets to those listed in this Security property. When set, applications wil not be able to override or add additional suites at runtime without changing this property. This should be a comma-delimited String. Example use:

wolfjsse.enabledCipherSuites=TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256

wolfjsse.enabledSupportedCurves (String) - Allows setting of specific ECC curves to be enabled for SSL/TLS connections. This propogates down to the native wolfSSL API wolfSSL_UseSupportedCurve(). If invalid/bad values are found when processing this property, connection establishment will fail with an SSLException. This should be a comma-delimited String. Example use:

wolfjsse.enabledSupportedCurves=secp256r1, secp521r1

wolfjsse.enabledSignatureAlgorithms (String) - Allows restriction of the signature algorithms sent in the TLS ClientHello Signature Algorithms Extension. By using/setting this property, native wolfSSL will not populate the extension with default values, which are based on what algorithms have been compiled into the native wolfSSL library. This should be a comma-delimited String of signature algorithm + MAC combinations. Example use:

wolfjsse.enabledSignatureAlgorithms=RSA+SHA256:ECDSA+SHA256

wolfjsse.keystore.type.required (String) - Can be used to specify a KeyStore type that is required to be used. If this is set, wolfJSSE will not allow use of any KeyStore instances that are not of this type. One use of this option is when using wolfCrypt FIPS 140-2/3 with wolfJCE registered as a JCE provider. This option can be used to restrict use of the wolfJCE "WKS" KeyStore type to help ensure conformance to using FIPS-validated cryptography. Other non-wolfJCE KeyStore implementations may not use/consume FIPS validated crypto.

wolfjsse.clientSessionCache.disabled (String) - Can be used to disable the Java client session cache. Disabling this will cause client-side session resumption to no longer resume, making all connections fall back to a full handshake. This should be set to the String "true" if you want to disable the Java client session cache. This does not need to be set to "enable" the cache. The Java client cache is enabled by default.

wolfjsse.clientSessionCache.disabled=true

If there are other Security properties you would like to use with wolfJSSE, please contact [email protected].

System Property Support

wolfJSSE allows some customization through the use of System properties. Since these are System properties and not Security properties, they will not get picked up if placed in the java.security file. That file is only used with/for Security properties (see section above).

javax.net.ssl.keyStore (String) - Can be used to specify the KeyStore file to use for KeyManager objects. An alternative to passing in the KeyStore file programatically at runtime.

javax.net.ssl.keyStoreType (String) - Can be used to specify the KeyStore type to use when getting KeyStore instances inside KeyManager objects.

javax.net.ssl.keyStorePassword (String) - Can be used to specify the KeyStore password to use for initializing KeyManager instances.

javax.net.ssl.trustStore (String) - Can be used to specify the KeyStore file to use with TrustManager objects. An alternative to passing in the KeyStore file programatically at runtime.

javax.net.ssl.trustStoreType (String) - Can be used to specify the KeyStore type to use when loading KeyStore inside TrustManager objects.

javax.net.ssl.trustStorePassword (String) - Can be used to specify the KeyStore password to use when loading KeyStore inside TrustManager objects.

jdk.tls.client.enableSessionTicketExtension (boolean) - Session tickets are enabled in different ways depending on the JDK implementation. For Oracle/OpenJDK and variants, this System property enables session tickets and was added in Java 13. Should be set to "true" to enable.

If there are other System properties you would like to use with wolfJSSE, please contact [email protected].

Release Notes

Release notes can be found in ChangeLog.md.

Support

For support inquiries and feedback please contact [email protected].