Quarkus - Using SSL With Native Executables

Prerequisites
Looks like it works out of the box?!?
Let’s disable SSL and see how it goes
Let’s start again with a clean slate
The TrustStore path
- Working with containers
Conclusion

We are quickly moving to an SSL-everywhere world so being able to use SSL is crucial.

In this guide, we will discuss how you can get your native executables to support SSL, as native executables don’t support it out of the box.

If you don’t plan on using native executables, you can pass your way as in JDK mode, SSL is supported without further manipulations.

Prerequisites

To complete this guide, you need:

less than 20 minutes
an IDE
GraalVM installed with JAVA_HOME and GRAALVM_HOME configured appropriately
Apache Maven 3.6.2+

This guide is based on the REST client guide so you should get this Maven project first.

Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive.

The project is located in the rest-client-quickstart directory.

Looks like it works out of the box?!?

If you open the application’s configuration file (src/main/resources/application.properties), you can see the following line:

org.acme.restclient.CountriesService/mp-rest/url=https://restcountries.eu/rest

which configures our REST client to connect to an SSL REST service.

Now let’s build the application as a native executable and run the tests:

./mvnw clean install -Pnative

And we obtain the following result:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

So, yes, it appears it works out of the box and this guide is pretty useless.

It’s not. The magic happens when building the native executable:

[INFO] [io.quarkus.creator.phase.nativeimage.NativeImagePhase] /opt/graalvm/bin/native-image -J-Djava.util.logging.manager=org.jboss.logmanager.LogManager -J-Dcom.sun.xml.internal.bind.v2.bytecode.ClassTailor.noOptimize=true -H:InitialCollectionPolicy=com.oracle.svm.core.genscavenge.CollectionPolicy$BySpaceAndTime -jar rest-client-1.0-SNAPSHOT-runner.jar -J-Djava.util.concurrent.ForkJoinPool.common.parallelism=1 -H:+PrintAnalysisCallTree -H:EnableURLProtocols=http,https --enable-all-security-services -H:-SpawnIsolates -H:+JNI --no-server -H:-UseServiceLoaderFeature -H:+StackTrace

The important elements are these 3 options:

-H:EnableURLProtocols=http,https --enable-all-security-services -H:+JNI

They enable the native SSL support for your native executable.

As SSL is de facto the standard nowadays, we decided to enable its support automatically for some of our extensions:

the Agroal connection pooling extension (quarkus-agroal),
the Amazon DynamoDB extension (quarkus-amazon-dynamodb),
the Hibernate Search Elasticsearch extension (quarkus-hibernate-search-elasticsearch),
the Infinispan Client extension (quarkus-infinispan-client).
the Jaeger extension (quarkus-jaeger),
the JGit extension (quarkus-jgit),
the Keycloak extension (quarkus-keycloak),
the Kubernetes client extension (quarkus-kubernetes-client),
the Mailer extension (quarkus-mailer),
the MongoDB extension (quarkus-mongodb-client),
the Neo4j extension (quarkus-neo4j),
the OAuth2 extension (quarkus-elytron-security-oauth2),
the REST client extension (quarkus-rest-client).

As long as you have one of those extensions in your project, the SSL support will be enabled by default.

Now, let’s just check the size of our native executable as it will be useful later:

$ ls -lh target/rest-client-1.0-SNAPSHOT-runner
-rwxrwxr-x. 1 gsmet gsmet 34M Feb 22 15:27 target/rest-client-1.0-SNAPSHOT-runner

Let’s disable SSL and see how it goes

Quarkus has an option to disable the SSL support entirely. Why? Because it comes at a certain cost. So if you are sure you don’t need it, you can disable it entirely.

First, let’s disable it without changing the REST service URL and see how it goes.

Open src/main/resources/application.properties and add the following line:

quarkus.ssl.native=false

And let’s try to build again:

./mvnw clean install -Pnative

The native executable tests will fail with the following error:

Exception handling request to /country/name/greece: com.oracle.svm.core.jdk.UnsupportedFeatureError: Accessing an URL protocol that was not enabled. The URL protocol https is supported but not enabled by default. It must be enabled by adding the --enable-url-protocols=https option to the native-image command.

This error is the one you obtain when trying to use SSL while it was not explicitly enabled in your native executable.

Now, let’s change the REST service URL to not use SSL in src/main/resources/application.properties:

org.acme.restclient.CountriesService/mp-rest/url=http://restcountries.eu/rest

And build again:

./mvnw clean install -Pnative

If you check carefully the native executable build options, you can see that the SSL related options are gone:

[INFO] [io.quarkus.creator.phase.nativeimage.NativeImagePhase] /opt/graalvm/bin/native-image -J-Djava.util.logging.manager=org.jboss.logmanager.LogManager -J-Dcom.sun.xml.internal.bind.v2.bytecode.ClassTailor.noOptimize=true -H:InitialCollectionPolicy=com.oracle.svm.core.genscavenge.CollectionPolicy$BySpaceAndTime -jar rest-client-1.0-SNAPSHOT-runner.jar -J-Djava.util.concurrent.ForkJoinPool.common.parallelism=1 -H:+PrintAnalysisCallTree -H:EnableURLProtocols=http -H:-SpawnIsolates -H:+JNI --no-server -H:-UseServiceLoaderFeature -H:+StackTrace

And we end up with:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

You remember we checked the size of the native executable with SSL enabled? Let’s check again with SSL support entirely disabled:

$ ls -lh target/rest-client-1.0-SNAPSHOT-runner
-rwxrwxr-x. 1 gsmet gsmet 25M Feb 22 15:19 target/rest-client-1.0-SNAPSHOT-runner

Yes, it is now 25 MB whereas it used to be 34 MB. SSL comes with a 9 MB overhead in native executable size.

And there’s more to it.

Let’s start again with a clean slate

Let’s revert the changes we made to the configuration file and go back to SSL with the following command:

git checkout -- src/main/resources/application.properties

And let’s build the native executable again:

./mvnw clean install -Pnative

The TrustStore path

You haven’t noticed anything but, while building the image, Quarkus has automatically set javax.net.ssl.trustStore to point to the cacerts file bundled in the GraalVM distribution. This file contains the root certificates.

This is useful when running tests but, obviously, it is not portable as this path is hardcoded.

You can check that pretty easily:

move your GraalVM directory to another place (let’s call it <new-graalvm-home>)
run the native executable ./target/rest-client-1.0-SNAPSHOT-runner
in a browser, go to http://localhost:8080/country/name/greece
you will have an Internal Server Error
in your terminal, you should have an exception: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty
hit Ctrl+C to stop the application

To make it work, you need to manually set javax.net.ssl.trustStore to point to the new GraalVM home:

./target/rest-client-1.0-SNAPSHOT-runner -Djavax.net.ssl.trustStore=<new-graalvm-home>/jre/lib/security/cacerts

Now, the application should work as expected:

in a browser, go to http://localhost:8080/country/name/greece
you should see a JSON output with some information about Greece
hit Ctrl+C to stop the application

The root certificates file of GraalVM might not be totally up to date. If you have issues with some certificates, your best bet is to include the cacerts file of a regular JDK instead.

Don’t forget to move your GraalVM directory back to where it was.

Working with containers

When working with containers, the idea is to bundle the certificates in the container and to point your binary to them using the system property mentioned above.

You can for example modify your Dockerfile.native as follows to copy the required files to your final image:

FROM quay.io/quarkus/ubi-quarkus-native-image:19.3.1-java11 as nativebuilder
RUN mkdir -p /tmp/ssl \
  && cp /opt/graalvm/lib/security/cacerts /tmp/ssl/

FROM registry.access.redhat.com/ubi8/ubi-minimal
WORKDIR /work/
COPY --from=nativebuilder /tmp/ssl/ /work/
COPY target/*-runner /work/application

# set up permissions for user `1001`
RUN chmod 775 /work /work/application \
  && chown -R 1001 /work \
  && chmod -R "g+rwX" /work \
  && chown -R 1001:root /work

EXPOSE 8080
USER 1001

CMD ["./application", "-Dquarkus.http.host=0.0.0.0", "-Djavax.net.ssl.trustStore=/work/cacerts"]

Conclusion

We make building native executable easy and, even if the SSL support in GraalVM is still requiring some serious thinking, it should be mostly transparent when using Quarkus.

Hopefully, the situation will improve in the future: the native executables size overhead will be reduced and the SunCE library might not be needed anymore.

We track GraalVM progress on a regular basis so we will promptly integrate in Quarkus any improvement with respect to SSL support.