feat: Add digest validation support to HTTP resolver

[zakisk]

This commit introduces content hash verification for the HTTP resolver by adding support for optional digest validation using SHA256 and SHA512 algorithms.

Changes:

• Add new 'digest' parameter accepting ':' format where algorithm can be 'sha256' or 'sha512'
• Implement digest validation logic using constant-time comparison to prevent timing-based side-channel attacks
• Add comprehensive unit tests covering valid matches, mismatches, invalid formats, and unsupported algorithms
• Add E2E tests to verify digest validation in real cluster scenarios
• Enable 'enable-http-resolver' feature flag in default configuration
• Update documentation with digest parameter description, usage examples, and commands to calculate SHA256/SHA512 hashes

Security considerations:

• Uses constant-time comparison to prevent timing attacks
• Digest validation is optional to maintain backward compatibility
• Digest values are logged for debugging

Fixes: #8759

Changes

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

The HTTP resolver now supports optional content integrity verification through a new `digest` parameter. Users can provide a cryptographic hash in the format `<algorithm>:<hash>` (where algorithm is either `sha256` or `sha512`) to verify that the fetched content matches the expected value. For example, `digest: sha256:f37cdd0e8611932bca52eed219c2b273161501510b37218fb79ca0a6a4487cff`. This parameter is optional and currently enabled by default, ensuring backward compatibility with existing HTTP resolver configurations.

[zakisk]

/kind feature

[zakisk]

I think that one E2E job failure is flake because before there was three jobs were failing

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: vdemeester

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

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [vdemeester]

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

[zakisk]

@vdemeester I guess E2E failure is flake because they are not consistent, yeah?

[vdemeester]

@vdemeester I guess E2E failure is flake because they are not consistent, yeah?

Yes, working on fixing it but it might take some times. One thing as well, e2e tests that change the configmaps are making the things flaky (because most things run in parallels) - I am working on fixing this as well.

[zakisk]

Yes, working on fixing it but it might take some times. One thing as well, e2e tests that change the configmaps are making the things flaky (because most things run in parallels) - I am working on fixing this as well.

@vdemeester I think #9224 fixes that, right?

[vdemeester]

Yes, working on fixing it but it might take some times. One thing as well, e2e tests that change the configmaps are making the things flaky (because most things run in parallels) - I am working on fixing this as well.

@vdemeester I think #9224 fixes that, right?

It is trying yes.

[waveywaves]

/retest

[waveywaves]

Added suggestions with a doc update and early validations to fail fast before a comparatively compute heavy call

[vdemeester]

ah @zakisk

Running tests with 'go test -race -v  -count=1 -tags=e2e -timeout=40m ./test/... '
Error: found 2 test(s) without @test:execution annotation:
  - TestHttpResolver (resolvers_test.go:474)
  - TestHttpResolver_Failure (resolvers_test.go:510)

You need to mark those tests, see here.