Async crypto: RNG

[bigbrett]

Async support for RNG.

• Adds the non-blocking Request() / Response() split to RNG generate, following the pattern established by the SHA async PR.
• Blocking wh_Client_RngGenerate{,Dma} are retained as thin wrappers over the new primitives, so existing callers (including the wolfCrypt RNG callback path) are unchanged.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #344

Scan targets checked: wolfhsm-crypto-bugs, wolfhsm-src

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Findings are non-blocking.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds asynchronous (split Request/Response) APIs for RNG generation, including a DMA variant, and updates docs/tests to cover the new async behavior.

Changes:

• Introduces async RNG Request/Response APIs (non-DMA and DMA) and refactors blocking wrappers to use them.
• Defines a max inline RNG payload size for single comm-buffer replies and documents caller-driven chunking.
• Extends crypto tests to directly exercise async RNG flows (including DMA).

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
wolfhsm/wh_message_crypto.h	Adds inline payload size cap macro for RNG responses.
wolfhsm/wh_client_crypto.h	Declares new async RNG APIs and documents usage/constraints.
wolfhsm/wh_client.h	Adds per-operation async DMA stash for RNG to support POST cleanup.
src/wh_client_crypto.c	Implements async RNG APIs, refactors blocking wrappers; adds DMA async request/response split.
test/wh_test_crypto.c	Adds direct async RNG and async DMA RNG tests.
docs/draft/async-crypto.md	Documents RNG async design, chunking policy, and API reference.

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