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reference, howto |
Container Scanning (ULTIMATE)
Introduced in GitLab Ultimate 10.4.
Overview
If you are using GitLab CI/CD, you can check your Docker images (or more precisely the containers) for known vulnerabilities by using Clair and klar, two open source tools for Vulnerability Static Analysis for containers.
You can take advantage of Container Scanning by either including the CI job in
your existing .gitlab-ci.yml
file or by implicitly using
Auto Container Scanning
that is provided by Auto DevOps.
GitLab checks the Container Scanning report, compares the found vulnerabilities between the source and target branches, and shows the information right on the merge request.
Use cases
If you distribute your application with Docker, then there's a great chance that your image is based on other Docker images that may in turn contain some known vulnerabilities that could be exploited.
Having an extra job in your pipeline that checks for those vulnerabilities, and the fact that they are displayed inside a merge request, makes it very easy to perform audits for your Docker-based apps.
Requirements
To enable Container Scanning in your pipeline, you need:
-
A GitLab Runner with the
docker
orkubernetes
executor running in privileged mode. If you're using the shared Runners on GitLab.com, this is enabled by default. -
Docker
18.09.03
or higher installed on the machine where the Runners are running. If you're using the shared Runners on GitLab.com, this is already the case. -
To build and push your Docker image to your project's Container Registry. The name of the Docker image should match the following scheme:
$CI_REGISTRY_IMAGE/$CI_COMMIT_REF_SLUG:$CI_COMMIT_SHA
The variables above can be found in the predefined environment variables document.
Configuration
For GitLab 11.9 and later, to enable Container Scanning, you must
include the
Container-Scanning.gitlab-ci.yml
template
that's provided as a part of your GitLab installation.
For GitLab versions earlier than 11.9, you can copy and use the job as defined
in that template.
Add the following to your .gitlab-ci.yml
file:
include:
template: Container-Scanning.gitlab-ci.yml
The included template will:
- Create a
container_scanning
job in your CI/CD pipeline. - Pull the already built Docker image from your project's Container Registry (see requirements) and scan it for possible vulnerabilities.
The results will be saved as a Container Scanning report artifact that you can later download and analyze. Due to implementation limitations, we always take the latest Container Scanning artifact available. Behind the scenes, the GitLab Klar analyzer is used and runs the scans.
Example
The following is a sample .gitlab-ci.yml
that will build your Docker Image, push it to the container registry and run Container Scanning.
variables:
DOCKER_DRIVER: overlay2
services:
- docker:stable-dind
stages:
- build
- test
include:
- template: Container-Scanning.gitlab-ci.yml
build:
image: docker:stable
stage: build
variables:
IMAGE: $CI_REGISTRY_IMAGE/$CI_COMMIT_REF_SLUG:$CI_COMMIT_SHA
script:
- docker info
- docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
- docker build -t $IMAGE .
- docker push $IMAGE
Vulnerability Whitelisting
If you want to whitelist specific vulnerabilities, you'll need to:
- Set
GIT_STRATEGY: fetch
in your.gitlab-ci.yml
file by following the instructions described in the overriding the Container Scanning template section of this document. - Define the whitelisted vulnerabilities in a YAML file named
clair-whitelist.yml
which must use the format described in the following whitelist example file. - Add the
clair-whitelist.yml
file to the git repository of your project
Overriding the Container Scanning template
If you want to override the job definition (for example, change properties like
variables
), you need to declare a container_scanning
job after the
template inclusion and specify any additional keys under it. For example:
include:
- template: Container-Scanning.gitlab-ci.yml
container_scanning:
variables:
GIT_STRATEGY: fetch
Available variables
Container Scanning can be configured using environment variables.
Environment Variable | Description | Default |
---|---|---|
KLAR_TRACE |
Set to true to enable more verbose output from klar. | "false" |
DOCKER_USER |
Username for accessing a Docker registry requiring authentication. | $CI_REGISTRY_USER |
DOCKER_PASSWORD |
Password for accessing a Docker registry requiring authentication. | $CI_REGISTRY_PASSWORD |
CLAIR_OUTPUT |
Severity level threshold. Vulnerabilities with severity level higher than or equal to this threshold will be outputted. Supported levels are Unknown , Negligible , Low , Medium , High , Critical and Defcon1 . |
Unknown |
REGISTRY_INSECURE |
Allow Klar to access insecure registries (HTTP only). Should only be set to true when testing the image locally. |
"false" |
CLAIR_VULNERABILITIES_DB_URL |
This variable is explicitly set in the services section of the Container-Scanning.gitlab-ci.yml file and defaults to clair-vulnerabilities-db . This value represents the address that the postgres server hosting the vulnerabilities definitions is running on and shouldn't be changed unless you're running the image locally as described in the Running the scanning tool section of the klar readme. |
clair-vulnerabilities-db |
CI_APPLICATION_REPOSITORY |
Docker repository URL for the image to be scanned. | $CI_REGISTRY_IMAGE/$CI_COMMIT_REF_SLUG |
CI_APPLICATION_TAG |
Docker respository tag for the image to be scanned. | $CI_COMMIT_SHA |
CLAIR_DB_IMAGE_TAG |
The Docker image tag for the postgres server hosting the vulnerabilities definitions. It can be useful to override this value with a specific version, for example, to provide a consistent set of vulnerabilities for integration testing purposes. | latest |
Security Dashboard
The Security Dashboard is a good place to get an overview of all the security vulnerabilities in your groups, projects and pipelines. Read more about the Security Dashboard.
Interacting with the vulnerabilities
Once a vulnerability is found, you can interact with it. Read more on how to interact with the vulnerabilities.
Vulnerabilities database update
For more information about the vulnerabilities database update, check the maintenance table.
Troubleshooting
docker: Error response from daemon: failed to copy xattrs
When the GitLab Runner uses the Docker executor and NFS is used
(e.g., /var/lib/docker
is on an NFS mount), Container Scanning might fail with
an error like the following:
docker: Error response from daemon: failed to copy xattrs: failed to set xattr "security.selinux" on /path/to/file: operation not supported.
This is a result of a bug in Docker which is now fixed.
To prevent the error, ensure the Docker version that the Runner is using is
18.09.03
or higher. For more information, see
issue #10241.