fix: include validation for forbidden namespaces

[anithapriyanatarajan]

Changes

This pull request introduces a new validation to prevent namespace-level configuration from being created in certain forbidden namespaces, specifically those prefixed with kube-, openshift-, or tekton-. The changes include the implementation of the validation logic, updates to the admission webhook, and tests to ensure correct enforcement.

• Added a new function validateNamespaceForConfig in pkg/webhook/configmapvalidation.go that checks if a namespace starts with kube-, openshift-, or tekton- and returns an error if so. This prevents creation of namespace-level configs in these forbidden namespaces.
• Updated the Admit method in ValidateConfigMap to invoke validateNamespaceForConfig for namespace-level configs and reject requests in forbidden namespaces, returning a detailed error response.

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps
• Has Tests included if any functionality added or changed
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Release Notes

NONE

/kind fix

[tekton-robot]

@anithapriyanatarajan: The label(s) kind/fix cannot be applied, because the repository doesn't have them.

Details

In response to this:

Changes

This pull request introduces a new validation to prevent namespace-level configuration from being created in certain forbidden namespaces, specifically those prefixed with kube-, openshift-, or tekton-. The changes include the implementation of the validation logic, updates to the admission webhook, and tests to ensure correct enforcement.

• Added a new function validateNamespaceForConfig in pkg/webhook/configmapvalidation.go that checks if a namespace starts with kube-, openshift-, or tekton- and returns an error if so. This prevents creation of namespace-level configs in these forbidden namespaces.
• Updated the Admit method in ValidateConfigMap to invoke validateNamespaceForConfig for namespace-level configs and reject requests in forbidden namespaces, returning a detailed error response.

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps
• Has Tests included if any functionality added or changed
• pre-commit Passed
• Follows the commit message standard
• Meets the Tekton contributor standards (including functionality, content, code)
• Has a kind label. You can add one by adding a comment on this PR that contains /kind <type>. Valid types are bug, cleanup, design, documentation, feature, flake, misc, question, tep
• Release notes block below has been updated with any user facing changes (API changes, bug fixes, changes requiring upgrade notices or deprecation warnings). See some examples of good release notes.
• Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

NONE

/kind fix

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[infernus01]

/retest

[infernus01]

/lgtm

[infernus01]

There's a contradiction between the webhook configuration and validation code. This means the validation logic never executes because the webhook is never called. Let's remove tekton-pipelines and default from the exclusion list to allow code-level validation to properly reject these configs with appropriate error messages.
Edit: you already did, thanks

[infernus01]

/approve

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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[infernus01]

/lgtm