Pushkar Joglekar
ba6776b2a6
* Add container image signing docs Signed-off-by: Sascha Grunert <sgrunert@redhat.com> * Creates a task page to verify signed control plane container images * Added info about cosigned and why we need cosign in experimental mode Updates based on PR review Apply suggestions from code review Co-authored-by: Tim Bannister <tim@scalefactory.com> * Uses K8s SBoM to get list of signed images Apply suggestions from code review Co-authored-by: Qiming Teng <tengqm@outlook.com> Co-authored-by: Chris Negus <cnegus@redhat.com> * Add current scope of sign/verify Co-authored-by: Sascha Grunert <sgrunert@redhat.com> Co-authored-by: Tim Bannister <tim@scalefactory.com> Co-authored-by: Qiming Teng <tengqm@outlook.com> Co-authored-by: Chris Negus <cnegus@redhat.com>
73 lines
2.5 KiB
Markdown
73 lines
2.5 KiB
Markdown
---
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title: Verify Signed Container Images
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content_type: task
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min-kubernetes-server-version: v1.24
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---
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<!-- overview -->
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{{< feature-state state="alpha" for_k8s_version="v1.24" >}}
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## {{% heading "prerequisites" %}}
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These instructions are for Kubernetes {{< skew currentVersion >}}. If you want
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to check the integrity of components for a different version of Kubernetes,
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check the documentation for that Kubernetes release.
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You will need to have the following tools installed:
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- `cosign` ([install guide](https://docs.sigstore.dev/cosign/installation/))
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- `curl` (often provided by your operating system)
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## Verifying image signatures
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For a complete list of images that are signed please refer
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to [Releases](/releases/download/).
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Let's pick one image from this list and verify its signature using
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the `cosign verify` command:
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```shell
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COSIGN_EXPERIMENTAL=1 cosign verify k8s.gcr.io/kube-apiserver-amd64:v1.24.0
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```
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{{< note >}}
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`COSIGN_EXPERIMENTAL=1` is used to allow verification of images signed
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in `KEYLESS` mode. To learn more about keyless signing, please refer to
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[Keyless Signatures](https://github.com/sigstore/cosign/blob/main/KEYLESS.md#keyless-signatures)
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. {{< /note >}}
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### Verifying images for all control plane components
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To verify all signed control plane images, please run this command:
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```shell
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curl -Ls https://sbom.k8s.io/$(curl -Ls https://dl.k8s.io/release/latest.txt)/release | grep 'PackageName: k8s.gcr.io/' | awk '{print $2}' > images.txt
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input=images.txt
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while IFS= read -r image
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do
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COSIGN_EXPERIMENTAL=1 cosign verify "$image"
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done < "$input"
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```
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Once you have verified an image, specify that image by its digest in your Pod
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manifests as per this
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example: `registry-url/image-name@sha256:45b23dee08af5e43a7fea6c4cf9c25ccf269ee113168c19722f87876677c5cb2`
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.
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For more information, please refer
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to [Image Pull Policy](/docs/concepts/containers/images/#image-pull-policy)
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section.
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## Verifying Image Signatures with Admission Controller
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For non-control plane images (
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e.g. [conformance image](https://github.com/kubernetes/kubernetes/blob/master/test/conformance/image/README.md))
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, signatures can also be verified at deploy time using
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[cosigned](https://docs.sigstore.dev/cosign/kubernetes/#cosigned-admission-controller)
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admission controller. To get started with `cosigned` here are a few helpful
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resources:
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* [Installation](https://github.com/sigstore/helm-charts/tree/main/charts/cosigned)
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* [Configuration Options](https://github.com/sigstore/cosign/tree/main/config)
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