fix(auth-proxy-set-headers): Validate authorization header values

[jkroepke]

What this PR does / why we need it:

Validate the values inside a config map linked by the auth-proxy-set-headers annotation.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• CVE Report (Scanner found CVE and adding report)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation only

Which issue/s this PR fixes

How Has This Been Tested?

Locally, manually.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added unit and/or e2e tests to cover my changes.
• All new and existing tests passed.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: jkroepke
Once this PR has been reviewed and has the lgtm label, please assign cpanato for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

Hi @jkroepke. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[netlify]

✅ Deploy Preview for kubernetes-ingress-nginx canceled.

Name	Link
🔨 Latest commit	41b04f2
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-ingress-nginx/deploys/68225ab65ddc8c000847c8da

[netlify]

✅ Deploy Preview for kubernetes-ingress-nginx canceled.

Name	Link
🔨 Latest commit	3c574c9
🔍 Latest deploy log	https://app.netlify.com/projects/kubernetes-ingress-nginx/deploys/6881c696f3897d00099de10d

[Gacko]

/triage accepted
/kind bug
/priority backlog
/hold

If you're concerned about code injection, I'd rather quote the value here as we already did here. Annotation validation is optional and can be turned off. Also your regular expression might break existing deployments, which then leads to people turning off annotation validation.