Image Overview: zookeeper-fips

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ZooKeeper FIPS

SASL should not be enabled without additional configuration when running in FIPS mode due to its use of DIGEST-MD5 for authentication

A Wolfi-based image tailored for ZooKeeper, incorporating the required bouncycastle FIPS modules (bcfips) to facilitate ZooKeeper’s operation in FIPS mode.

Both OpenJDK and ZooKeeper have been configured to harness the BouncyCastle FIPS API at their core. The included bcfips module meets FIPS 140-2 compliance requirements and is accredited under: FIPS certificate 4616.

Disclaimer

If SASL authentication is enabled, Zookeeper will default to using DIGEST-MD5 which is not FIPS compliant. Instead, configure Zookeeper to use mTLS, or GSSAPI and Kerberos for authentication. Note that the Kerberos KDC server will need to be configured to run with FIPS approved algorithms.

This image is equipped with the essential components for ZooKeeper to operate in FIPS mode. However, it’s important for users to ensure they use it in line with FIPS compliance standards.

This includes tasks such as KeyStore generation, configuration, and launching ZooKeeper with the correct configuration parameters. More guidance is provided in the sections below.

KeyStore

ZooKeeper requires a bcfips-compatible KeyStore to manage its SSL/TLS certificates.

Although ZooKeeper supports various KeyStore types, only BCKFS offers the capability to operate in approved (strict) mode under FIPS standards, ensuring only approved ciphers are used.

BCKFS KeyStore creation

Refer to the official documentation for information on how to create and configure a KeyStore.

Note: The KeyStore needs to be generated on a seperate image, as the keytool application will not operate when bcfips is running in approved mode. keytool is hard coded to pass a new SecureRandom(), which will always fail the approved RNG test. However, the generated KeyStore will use FIPS compliant ciphers and will operate correctly in a FIPS enabled environment.

Below is an example, using a wolfi-base container to generate a bckfs KeyStore:

docker run -v $(pwd):/tmp/keystore -it cgr.dev/chainguard/wolfi-base:latest sh
...

apk update && apk add curl openjdk-17-default-jvm

# https://www.bouncycastle.org/fips-java for latest `bc-fips` version
curl https://downloads.bouncycastle.org/fips-java/bc-fips-<VERSION>.jar \
-o bc-fips.jar

keytool -v -keystore /tmp/keystore/server.keystore \
  -J--add-exports=java.base/sun.security.provider=ALL-UNNAMED \
  -storetype bcfks \
  -providername BCFIPS \
  -providerclass org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider \
  -providerpath bc-fips.jar \
  -alias "localhost" \
  -genkeypair -sigalg SHA512withRSA -keyalg RSA \
  -dname CN="localhost" \
  -storepass "<YOUR TLS KEYSTORE PASSWORD>"

Run image

This image aligns with the current Bitnami image regarding its entrypoint and command-line arguments. Also see the ZooKeeper GitHub repository

Running in a production environment

Deploy with Helm

To deploy ZooKeeper FIPS using Helm, open a terminal and run the following command:

helm install -n zookeeper zookeeper oci://registry-1.docker.io/bitnamicharts/zookeeper \
  --set image.registry=cgr.dev,image.repository=<REGISTRY>/zookeeper,image.tag=latest

For additional configuration options provided in the chart, please see Bitnami’s documentation here.

The KeyStore will need to be passed through as a volume (via extraVolumes), and TLS will need to be configured to match your environment.

Deploy with Docker

Alternatively, ZooKeeper FIPS can be deployed with Docker. Create a config file for ZooKeeper:

# ZooKeeper config
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/tmp/zookeeper
clientPort=2181

# Use BCFKS
ssl.keyStore.location=/usr/share/java/zookeeper/conf/server.keystore
ssl.keyStore.type=bcfks

This uses a standard ZooKeeper configuration with the default KeyStore format set to BCFKS. In this example, we’ve set the path for the KeyStore to /usr/share/java/zookeeper/conf/server.keystore.

Run it with Docker:

docker run \
  -v /path/to/server.keystore:/usr/share/java/zookeeper/conf/server.keystore \
  -v /path/to/your/zoo.cfg:/usr/share/java/zookeeper/conf/zoo.cfg \
  -p <YOUR PORT>:2181 \
  -e JDK_JAVA_OPTIONS="-Djavax.net.ssl.trustStoreType=FIPS -Dzookeeper.ssl.keyStore.password=<KEYSTORE PASSWORD>" \
  --entrypoint zkServer.sh \
  cgr.dev/<REGISTRY>/zookeeper-fips:latest \
  start-foreground

Where <YOUR PORT> is the port on the host you’d like to forward to.

Note that if you’ve configured a secure port for ZooKeeper FIPS, you’ll forward that instead of the standard port.

ZooKeeper will likely need additional configuration depending on your environment. For more resources, please see ZooKeeper’s admin guide.

FIPS validation

ZooKeeper itself does not provide any verbosity on systems running in FIPS mode. However, when ZooKeeper starts the BC FIPS libraries should be visible.

You can check bcfips is enforcing minimum password lengths, by running the container with a non-compliant ZooKeeper KeyStore password, such as 1234:

Caused by: org.bouncycastle.crypto.fips.FipsUnapprovedOperationError:
password must be at least 112 bits

Debugging

KeyStore corrupted error upon launch

Error Message:

BCFKS KeyStore corrupted: MAC calculation failed.

Solution: The error indicates that a KeyStore was detected, but there was an issue parsing it. Usually this means that the password used to create the KeyStore does not match what was provided to ZooKeeper.

Password must be at least 112 bits

Error Message:

Exception in thread "main" java.security.GeneralSecurityException: Error generating an encryption key from the provided password
...
Caused by: org.bouncycastle.crypto.fips.FipsUnapprovedOperationError: password must be at least 112 bits

Solution: This is expected whenever ZooKeeper is running in strict (approved) mode for FIPS. Choose a KeyStore password which is compliant.