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Prow (beta)


NOTE: ClusterFuzzLite for Prow is in beta. If there are any issues please file at github.com/google/clusterfuzzlite/issues

This document explains how to set up ClusterFuzzLite on Prow. This document assumes the reader has set up Prow on their repo.

First, you must create a Google Cloud Storage Bucket. This will be refered to as <your-cloud-bucket> in the config examples in this document. The bucket will be used to store crashes, builds, corpora, and coverage reports.

Then you must create a service account with access to both <your-cloud-bucket> and the Prow Results Bucket. To do this:

  1. Create a Cloud Service account in your Project
    gcloud beta iam service-accounts create `<sa-name>` --project=`<project-id>` --description=`<sa-description>` --display-name=`<sa-display-name>`
    
  2. Give the Cloud Service account access to BOTH the k8s Prow Results Bucket AND <your-cloud-bucket> using these commands:
  gsutil iam ch "serviceAccount:<sa-name>:roles/storage.objectAdmin" "<your-cloud-bucket>"
  gsutil iam ch "serviceAccount:<sa-name>:roles/storage.objectAdmin" "<k8s-Prow-results-bucket>"
  1. Create a new K8s service account with a distinct name (referred <K8s-SA> for the rest of this document):

  2. Add the Google Cloud Service account to the annotations for the K8s service account like so:
    apiVersion: v1
    kind: ServiceAccount
    metadata:
      annotations:
        iam.gke.io/gcp-service-account: <your-cloud-service-account>
      name: `<K8s-SA>`
      namespace: test-pods
    
  3. Run bind-service-accounts.sh to bind <K8s-SA> to your Google Cloud Service Account.

Note that the configuration examples set the environment variable CFL_PLATFORM this value is general for all prow users. Do not change it.

Presubmit/Postsubmit fuzzing

To add a fuzzing workflow that runs on all pull requests to your project, add the following to your job config under either Presubmits or Postsubmits:

- name: <your-prowjob-name>
  labels:
    preset-dind-enabled: "true"
  decorate: true
  spec:
    serviceAccountName: <K8s-SA>
    containers:
    - image: gcr.io/k8s-testimages/clusterfuzzlite:latest
      command:
        - runner.sh
      args:
        - python3
        - "/opt/oss-fuzz/infra/cifuzz/cifuzz_combined_entrypoint.py"
      # docker-in-docker needs privileged mode
      securityContext:
        privileged: true
      env:
      - name: MODE
        value: code-change
      - name: SANITIZER
        value: address # Change this to whatever sanitizer you want to use.
      - name: CLOUD_BUCKET
        value: <your-cloud-bucket>
      - name: CFL_PLATFORM
        value: prow

You can copy and paste this example, but make sure to set <your-prowjob-name>, <K8s-SA>, and <your-cloud-bucket> to the appropriate values.

You can set the FUZZ_SECONDS env var to change the amount of time ClusterFuzzLite will fuzz PRs for. You can modify the SANITIZER env var to pick the sanitizer you want to use.

Batch Fuzzing

To enable batch fuzzing, add the following to your prow job config for periodic jobs:

- name: <your-prowjob-name>
  labels:
    preset-dind-enabled: "true"
  decorate: true
  extra_refs:
  - org: <org>
    repo: <repo>
    base_ref: <branch> # This should be the branch you want to fuzz.
  interval: 24h  # This can be a cron as well.
  spec:
    serviceAccountName: <K8s-SA>
    containers:
    - image: gcr.io/k8s-testimages/clusterfuzzlite:latest
      command:
        - runner.sh
      args:
        - python3
        - "/opt/oss-fuzz/infra/cifuzz/cifuzz_combined_entrypoint.py"
      # docker-in-docker needs privileged mode
      securityContext:
        privileged: true
      env:
      - name: MODE
        value: batch
      - name: SANITIZER
        value: address # Change this to whatever sanitizer you want to use.
      - name: CLOUD_BUCKET
        value: <your-cloud-bucket>
      - name: FUZZ_SECONDS
        value: 3600  # 1 Hour. You  can change this.
      - name: CFL_PLATFORM
        value: prow

You can copy and paste this example, but make sure to set <your-prowjob-name>, <K8s-SA>, <your-cloud-bucket>, <org>, <repo> and <branch> to the appropriate values.

You can modify the FUZZ_SECONDS env var to change the amount of time ClusterFuzzLite will fuzz for. You can modify the SANITIZER env var to pick the sanitizer you want to use.

Corpus pruning

Corpus pruning minimizes a corpus by removing redundant items while keeping the same code coverage. To enable this, add the following to your prow job config for periodic jobs.

- name: <your-prowjob-name>
  labels:
    preset-dind-enabled: "true"
  decorate: true
  extra_refs:
  - org: <org>
    repo: <repo>
    base_ref: <branch> # This should be the branch you want to fuzz.
  interval: 24h # This can be a cron as well.
  spec:
    serviceAccountName: <K8s-SA>
    containers:
    - image: gcr.io/k8s-testimages/clusterfuzzlite:latest
      command:
        - runner.sh
      args:
        - python3
        - "/opt/oss-fuzz/infra/cifuzz/cifuzz_combined_entrypoint.py"
      # docker-in-docker needs privileged mode
      securityContext:
        privileged: true
      env:
      - name: MODE
        value: prune
      - name: CLOUD_BUCKET
        value: <your-cloud-bucket>
      - name: CFL_PLATFORM
        value: prow

You can copy and paste this example, but make sure to set <your-prowjob-name>, <K8s-SA>, <your-cloud-bucket>, <org>, <repo> and <branch> to the appropriate values. We recommend scheduling pruning to run once a day.

Coverage reports

Periodic coverage reports can also be generated using the latest corpus. To enable this, add the following to your prow job config for periodic jobs:

- name: <your-prowjob-name>
  labels:
    preset-dind-enabled: "true"
  decorate: true
  extra_refs:
  - org: <org>
    repo: <repo>
    base_ref: <branch> # This should be the branch you want to fuzz.
  interval: 24h # Note: this can be a cron as well.
  spec:
    serviceAccountName: <K8s-SA>
    containers:
    - image: gcr.io/k8s-testimages/clusterfuzzlite:latest
      command:
        - runner.sh
      args:
        - python3
        - "/opt/oss-fuzz/infra/cifuzz/cifuzz_combined_entrypoint.py"
      # docker-in-docker needs privileged mode
      securityContext:
        privileged: true
      env:
      - name: MODE
        value: coverage
      - name: SANITIZER
        value: coverage
      - name: CLOUD_BUCKET
        value: <your-cloud-bucket>
      - name: CFL_PLATFORM
        value: prow

You can copy and paste this example, but make sure to set <your-prowjob-name>, <K8s-SA>, <your-cloud-bucket>, <org>, <repo> and <branch> to the appropriate values. We recommend scheduling coverage reports to run once a day.

Testing it Out

You can test each of the workflows by Running the Prowjob Locally.

Storage Layout

Artifacts produced by ClusterFuzzLite are stored in <your-cloud-bucket>. The bucket has the following layout.

  1. Coverage report: /coverage/latest/report/linux/index.html
  2. Builds: /build/-/
  3. Corpora: /corpus//
  4. Crashes: /crashes/// and /crashes///.summary (output from crash).

Viewing Crashes

You can view your crashes on Deck by clicking the Artifacts button on the top of the page for your prowjob run. Crashes will be located in artifacts/out/artifacts/fuzzer/.