[pimlock]

Summary

Validate the HTTP session API proposed in NVIDIA/OpenShell#4359 with AWS SigV4 signing. External request middleware can transform the body first; the supervisor then signs the final request with credentials that never enter the external middleware protocol.

This draft lives in the personal fork as a validation example. Its base is frozen at upstream PR head 0dc751b086dd3a2190b9b87fba956e2ea36fd6c7, so the diff contains only this use case.

Related Issue

Validation for NVIDIA/OpenShell#4359, part of NVIDIA/OpenShell#2431. This fork has issues disabled; this validation draft does not close an upstream issue.

Changes

• Move SigV4 signing and its AWS dependencies into the built-ins crate behind a typed, trusted in-process API.
• Keep signing after external request middleware completes and credentials are resolved, with existing endpoint configuration and the 10 MiB signing limit.
• Preserve the network crate's public signing exports for existing Rust callers.
• Extend the relay regression test to verify the final payload hash after body transformation, secret omission from middleware preflights, and rejection above the signing limit.

Testing

• All 32 built-in tests pass.
• All 1,587 network unit tests pass, with two existing tests ignored.
• mise run pre-commit passes.

Shared runtime validation: the Docker HTTP session content-guard E2E suite passed with both signing implementations applied. No live AWS requests were tested. The full repository suite stopped at endpoint_selector_single_star_crosses_path_separators; the same prover failure reproduces on the unchanged upstream PR head.

Checklist

• Follows Conventional Commits.
• Commits are signed off for DCO.
• Crate and user documentation explain the credential boundary and endpoint configuration.

The trusted signer is selected by endpoint signing fields. It is not an externally registered service or a network_middlewares binding. This validates composition with the session API without adding a public credential-visible hook.

Companion validation: Git signing, based independently on the same frozen API head.