Feature/crytpo pbkdf2

[rahulmedicharla]

What

This PR implements the PBKDF2 support in the webcrypto module following the WebCrypto Api specification.

Why?

Having support of the PBKDF2 makes our implementation compliant with web crypto API

Checklist

• I have performed a self-review of my code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have added tests for my changes.
• I have run linter and tests locally (make check) and all pass.

Checklist: Documentation (only for k6 maintainers and if relevant)

Please do not merge this PR until the following items are filled out.

• I have added the correct milestone and labels to the PR.
• I have updated the release notes: link
• I have updated or added an issue to the k6-documentation: grafana/k6-docs#NUMBER if applicable
• I have updated or added an issue to the TypeScript definitions: grafana/k6-DefinitelyTyped#NUMBER if applicable

Related PR(s)/Issue(s)

Closes #4267

[CLAassistant]

All committers have signed the CLA.

[oleiade]

I've left a couple of nits behind, but overall, this looks good to me 👍🏻

Great work there, and really happy to see this feature move forward 🙇🏻

[oleiade]

This is a nit

I'm not sure where they got it from (I couldn't get a hold of that specific requirement in the specification), but the mozilla web api documentation for the PBKDF2 Params struct indicates it should be at least 16 bytes long, which makes sense to me: https://developer.mozilla.org/en-US/docs/Web/API/Pbkdf2Params#salt.

I remember the IV for encryption/decryption with AES should be 16 bytes though, maybe that's linked.

Even though there is no specific test for it in WPT, I think it would make sense to add that guardrail nonetheless, and add a unit test of our own, and document that behavior?

  byteSalt, err := common.ToBytes(salt.Export())
  if err != nil {
      return nil, err
  }
  if len(byteSalt) < 16 {
      return nil, NewError(OperationError, "salt must be at least 16 bytes")  // Similar error as when the iv is not 16 bytes in AES
  }

[rahulmedicharla]

@oleiade some WPT pbkdf2 tests use a 4 byte salt. I can update the tests to make them at min 16, but wanted to run it by you first if you wanted to me to change the actual test cases.

[oleiade]

@rahulmedicharla I wouldn't, we really want to keep the WPT tests as close as possible to the originals 🙇🏻

The Web Platform Tests are currently red though (I did not notice) was it always the case or did it just happen?

[rahulmedicharla]

@oleiade no that just happened, it's because the WPT tests have valid test cases where the salt length is 4 bytes, so if I add the 16 byte restriction they are failing. If we don't want to change the WPT tests, we may have to revert that change.

[oleiade]

@rahulmedicharla I see, then apologies for the useless round-trip. Please revert the 16 bytes restriction. Our top priority should be for the WPT suite to pass. Sorry again for making you lose time.

I poked the k6 maintainers team on this PR, and once the tests are green again, I'll make sure we merge it as soon as possible 🙇🏻

[rahulmedicharla]

@oleiade, no worries, I reverted the changes so it should pass now.

[AgnesToulet]

LGTM! Thanks for your contribution 🚀

[oleiade]

Thanks a ton for you contribution @rahulmedicharla 🙇🏻