Explicitly reduce user to the same as defined in the container

[RichardoC]

What this PR does / why we need it:
This reduces the pod user permissions to the same defined in Dockerfile:23
This makes it easier for administrators and security tooling to tell this workload is running as non-root

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: RichardoC
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[RichardoC]

Looks like https://github.com/kubernetes/community/blob/master/contributors/guide/pull-requests.md#run-local-verifications needs updating

$ make test-integration
++ cat version.txt
+ VERSION=dev
+ [[ ! dev =~ ^([0-9]+[.][0-9]+)[.]([0-9]+)(-(alpha|beta)[.]([0-9]+))?$ ]]
+ printerr 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
+ echo 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
Version dev must be 'X.Y.Z', 'X.Y.Z-alpha.N', or 'X.Y.Z-beta.N'
+ exit 1
++ cat version.txt
+ VERSION=dev
+ [[ ! dev =~ ^([0-9]+[.][0-9]+)[.]([0-9]+)(-(alpha|beta)[.]([0-9]+))?$ ]]
+ printerr 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
+ echo 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
Version dev must be 'X.Y.Z', 'X.Y.Z-alpha.N', or 'X.Y.Z-beta.N'
+ exit 1
make: *** No rule to make target 'test-integration'.  Stop.
$ make verify
++ cat version.txt
+ VERSION=dev
+ [[ ! dev =~ ^([0-9]+[.][0-9]+)[.]([0-9]+)(-(alpha|beta)[.]([0-9]+))?$ ]]
+ printerr 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
+ echo 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
Version dev must be 'X.Y.Z', 'X.Y.Z-alpha.N', or 'X.Y.Z-beta.N'
+ exit 1
++ cat version.txt
+ VERSION=dev
+ [[ ! dev =~ ^([0-9]+[.][0-9]+)[.]([0-9]+)(-(alpha|beta)[.]([0-9]+))?$ ]]
+ printerr 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
+ echo 'Version dev must be '\''X.Y.Z'\'', '\''X.Y.Z-alpha.N'\'', or '\''X.Y.Z-beta.N'\'''
Version dev must be 'X.Y.Z', 'X.Y.Z-alpha.N', or 'X.Y.Z-beta.N'
+ exit 1
make: *** No rule to make target 'verify'.  Stop.

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/lifecycle stale

[RichardoC]

/remove-lifecycle stale

[k8s-triage-robot]

The Kubernetes project currently lacks enough contributors to adequately respond to all PRs.

This bot triages PRs according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the PR is closed

You can:

• Mark this PR as fresh with /remove-lifecycle stale
• Close this PR with /close
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/lifecycle stale

[RichardoC]

/remove-lifecycle stale

[micahhausler]

Hey sorry for the late review, I see a RUN chown 65532 _output/bin/aws-iam-authenticator in the Dockerfile, but no USER directive. Also when using --generate-kubeconfig the containerized server needs to write a kubeconfig formatted file for the API to consume. Unless that host directory is mounted as writable by 65532, this would break that functionality right?

[RichardoC]

Hey sorry for the late review, I see a RUN chown 65532 _output/bin/aws-iam-authenticator in the Dockerfile, but no USER directive. Also when using --generate-kubeconfig the containerized server needs to write a kubeconfig formatted file for the API to consume. Unless that host directory is mounted as writable by 65532, this would break that functionality right?

You're right, I'd thought https://github.com/kubernetes-sigs/aws-iam-authenticator/blob/2596d17f99149e9ce518e8bc4447e404aa655a57/Dockerfile#L26C59-L26C79 was a container running as 65532 with that user directive but based on https://github.com/kubernetes/kubernetes/blob/1c93be24ee8a607f6add6bb1869d5d2006ffa783/build/go-runner/Dockerfile it isn't.

I can add the USER directive, but you're right about that host volume needing to be mounted as the correct group. We could default to the current group, and update the docs that this folder needs to be owned by that gid, or the manifest updated?

[micahhausler]

I can add the USER directive, but you're right about that host volume needing to be mounted as the correct group. We could default to the current group, and update the docs that this folder needs to be owned by that gid, or the manifest updated?

Altering the USER would be a breaking change to the resulting image and anyone deploying from it. Given that .spec.securityContext.runAsNonRoot and .spec.securityContext.runAsUser can be used to override the USER value, its probably not needed for most use cases.

Given that the file here is just an example (deploy/example.yaml) is this change necessary? If we had a helm chart, I could see the need to set or configure these values.