Add compile-time crypto callback async poll for record ciphers

[julek-wolfssl]

Summary

• Adds WOLF_CRYPTO_CB_ASYNC_POLL, giving crypto callback devices a QAT/Nitrox-style "poll to fill output" completion model for TLS record ciphers (AES and 3DES) instead of the re-invoke model, fixing silent record corruption when a callback returns WC_PENDING_E.
• Without the feature (and without a software/QAT/Cavium backend), a pending bulk cipher op now errors out with ASYNC_OP_E instead of corrupting the record.

Test plan

• tests/api/test_async.c covers direct AES-GCM/CBC/CCM and 3DES poll completion at multiple pend depths
• Negative cases for cipher types defined but not dispatched (ChaCha, single DES)
• Full TLS 1.3 handshake+echo including the no-poll failure path

[Copilot]

Pull request overview

This PR introduces a compile-time “poll to fill output” completion model for crypto-callback–backed async TLS record ciphers (AES + 3DES) via WOLF_CRYPTO_CB_ASYNC_POLL, aiming to prevent silent record corruption when a callback returns WC_PENDING_E by ensuring completion happens during async polling (or fails loudly when no completion path exists).

Changes:

• Adds a new crypto-callback algo type (WC_ALGO_TYPE_ASYNC_POLL) and wc_CryptoCb_Poll() entry point to support poll-based completion.
• Routes selected async operations through callback polling during wolfSSL_AsyncPoll() / async event polling, and converts “pending but no completion path” into ASYNC_OP_E for TLS record ciphers.
• Adds a dedicated async test suite (tests/api/test_async.c) plus CI coverage to exercise poll completion and negative paths.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
wolfssl/wolfcrypt/types.h	Adds WC_ALGO_TYPE_ASYNC_POLL to identify callback poll re-entry.
wolfssl/wolfcrypt/settings.h	Adds a config-time guard for WOLF_CRYPTO_CB_ASYNC_POLL vs. WC_ASYNC_NO_CRYPT.
wolfssl/wolfcrypt/cryptocb.h	Declares wc_CryptoCb_Poll() for callback poll completion.
wolfssl/wolfcrypt/async.h	Extends WC_ASYNC_DEV to track a callback device ID for polling.
wolfcrypt/src/cryptocb.c	Implements wc_CryptoCb_Poll() to re-enter the callback with WC_ALGO_TYPE_ASYNC_POLL.
wolfcrypt/src/async.c	Integrates callback polling into async event polling/queue polling and sets routing state.
tests/api/test_async.h	Declares new async poll-completion unit tests and registration macro.
tests/api/test_async.c	Adds unit + TLS 1.3 integration tests for poll completion and negative cases.
tests/api/include.am	Adds new async test sources to the unit test build and dist list.
tests/api.c	Registers the new “async” test group in the test runner.
src/tls13.c	Fails fast with ASYNC_OP_E when a bulk cipher pends but no completion path exists.
src/internal.c	Applies the same “no completion path” failure for TLS 1.2 record ciphers; adjusts async pop logic for poll-completed events; preserves ssl->error on send failures.
examples/async/user_settings.h	Silences the new async-crypt + cryptocb TLS warning for the async example config.
configure.ac	Adds a configure-time warning about cryptocb+async TLS limitations and silences source-level warnings.
.wolfssl_known_macro_extras	Registers WOLF_CRYPTO_CB_ASYNC_POLL as a recognized macro.
.github/workflows/async-examples.yml	Adds CI job to build with WOLF_CRYPTO_CB_ASYNC_POLL and run the async test group.

Comments suppressed due to low confidence (1)

wolfcrypt/src/async.c:772

• In wolfAsync_EventQueuePoll(), the callback poll is performed whenever cryptocb.devId is set, regardless of the event’s current ret value. Polling a non-pending event can incorrectly overwrite a successful completion with WC_NO_PENDING_E (or another error) depending on the device’s behavior. This should only poll when event->ret is still WC_PENDING_E.

                    if (asyncDev->cryptocb.devId != INVALID_DEVID) {
                        /* Re-enter the crypto callback to complete the job
                         * and fill the output buffer. */
                        event->ret =
                            wc_CryptoCb_Poll(asyncDev->cryptocb.devId);

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[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (2)

wolfcrypt/src/cryptocb.c:481

• wc_CryptoCb_Poll() currently lets WC_NO_PENDING_E propagate from the device callback. That contradicts the intent to never report “no pending” for an in-flight job and can also leave a DONE event with ret==WC_NO_PENDING_E, which wolfSSL_AsyncPop() treats specially (doesn’t clear ssl->asyncDev), potentially leaving stale async state. Consider mapping WC_NO_PENDING_E to a hard failure (WC_HW_E) like other unsupported polling cases.

        ret = dev->cb(devId, &info, dev->ctx);
        if (ret == WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE) ||
            ret == WC_NO_ERR_TRACE(NOT_COMPILED_IN)) {
            /* Device does not implement polling: job can never complete. */
            ret = WC_NO_ERR_TRACE(WC_HW_E);
        }

wolfcrypt/src/async.c:433

• wolfAsync_DevCtxInit() stamps asyncDev->cryptocb.devId for AES/3DES whenever WOLF_CRYPTO_CB_ASYNC_POLL is enabled. In builds that also enable a hardware async backend (Intel QAT / Cavium / async SW), this can cause wolfAsync_EventPoll() to attempt wc_CryptoCb_Poll() for a non-crypto-callback devId, overriding the real backend’s pending state and potentially forcing WC_HW_E. Consider only enabling the poll-routing stamp when crypto callbacks are the active async backend for bulk ciphers (i.e., not HAVE_INTEL_QA/HAVE_CAVIUM/WOLFSSL_ASYNC_CRYPT_SW).

#if defined(WOLF_CRYPTO_CB) && defined(WOLF_CRYPTO_CB_ASYNC_POLL)

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.