fix: validate that a method and a wildcard won't appear together

[EyalPazz]

What type of PR is this?
/kind bug

Which issue(s) this PR fixes:

Fixes #3647

Does this PR introduce a user-facing change?:

Doesn't allow a user to provide both an asterisk and another method/s along with it in `HTTPCORSFilter.AllowMethods`

[k8s-ci-robot]

Hi @EyalPazz. Thanks for your PR.

I'm waiting for a kubernetes-sigs 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.

[robscott]

Thanks @EyalPazz! There's been some good discussion about this in Slack, where there is conflicting guidance from MDN and the Fetch Living Standard, where the first suggests that this is an invalid combination and the second has been summarized well by @elizabeth-dev:

For Access-Control-Expose-Headers, Access-Control-Allow-Methods, and Access-Control-Allow-Headers response headers, the value * counts as a wildcard for requests without credentials.

with credentials being defined as:

Credentials are HTTP cookies, TLS client certificates, and authentication entries (for HTTP authentication).

Given the ambiguity here, my preference is to start with the tightest possible reasonable validation, and loosen if/when needed, since it would be very difficult (a backwards incompatible change) to tighten this validation in the future. So with all of the above context, my vote is to merge this PR. Open to other opinions.

/cc @howardjohn @youngnick @elizabeth-dev
/ok-to-test
/approve

[k8s-ci-robot]

@robscott: GitHub didn't allow me to request PR reviews from the following users: elizabeth-dev.

Note that only kubernetes-sigs members and repo collaborators can review this PR, and authors cannot review their own PRs.

In response to this:

Thanks @EyalPazz! There's been some good discussion about this in Slack, where there is conflicting guidance from MDN and the Fetch Living Standard, where the first suggests that this is an invalid combination and the second has been summarized well by @elizabeth-dev:

For Access-Control-Expose-Headers, Access-Control-Allow-Methods, and Access-Control-Allow-Headers response headers, the value * counts as a wildcard for requests without credentials.

with credentials being defined as:

Credentials are HTTP cookies, TLS client certificates, and authentication entries (for HTTP authentication).

Given the ambiguity here, my preference is to start with the tightest possible reasonable validation, and loosen if/when needed, since it would be very difficult (a backwards incompatible change) to tighten this validation in the future. So with all of the above context, my vote is to merge this PR. Open to other opinions.

/cc @howardjohn @youngnick @elizabeth-dev
/ok-to-test
/approve

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.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: EyalPazz, robscott

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

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [robscott]

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

[youngnick]

Agreed that starting with the tightest validation is better here.

[elizabeth-dev]

+1 to @robscott's conclusion. I wonder if we could find people from MDN to weigh in on why their docs seem to differ from the standard.

[robscott]

@EyalPazz this LGTM if you can get the tests to pass.

[youngnick]

Looks like this just needs a make generate run.

[EyalPazz]

/retest

[EyalPazz]

The problem was with contains, it's only for strings

[EyalPazz]

@robscott

[youngnick]

/lgtm