Add X25519 non-blocking support and async example improvements by dgarske · Pull Request #9721 · wolfSSL/wolfssl

dgarske · 2026-01-29T00:04:33Z

Description

Add non-blocking (non-blocking crypto) support for Curve25519 (X25519) key generation and shared secret. This enables WC_X25519_NONBLOCK for use with TLS, similar to the existing WC_ECC_NONBLOCK support. Requires CURVE25519_SMALL (the small fe_low_mem.c implementation).

New Features

X25519 non-blocking key gen (wc_curve25519_make_key) and shared secret (wc_curve25519_shared_secret) using FP_WOULDBLOCK yield pattern.
Non-blocking curve25519_nb() function in fe_low_mem.c with state machine for iterative scalar multiplication.
TLS integration: WC_X25519_NONBLOCK support in src/tls.c and src/internal.c for key gen and ECDH during handshake.
New async TLS client/server examples (examples/async/) with standalone Makefile (no configure needed).
user_settings_curve25519nonblock.h example config.
Async examples CI workflow (.github/workflows/async-examples.yml).
WOLFSSL_STATIC_MEMORY support in async examples using wolfSSL_CTX_load_static_memory.

Fixes

Fix async SW guard in curve25519.c — require WOLFSSL_ASYNC_CRYPT_SW for software async simulation symbols.
Fix mutual auth in async examples — server loads self-signed client certs (ECC/ED25519) as their own CA.
Fix C90 mixed-declaration violations in SP ECC non-blocking code (sp_c32.c, sp_c64.c, sp_x86_64.c, sp_arm32.c, sp_arm64.c, sp_armthumb.c, sp_cortexm.c) — move typedef before statements.
Fix register ... asm() pedantic warning on macOS in sp_x86_64.c with __APPLE__ && __MACH__ guard.
Add missing user_settings_curve25519nonblock.h to examples/configs/include.am.

Testing

CI matrix tests async examples with: default, WOLFSSL_SMALL_CERT_VERIFY, WOLFSSL_STATIC_MEMORY.
8 TLS test combinations per matrix entry: ECC/X25519 x TLS 1.2/1.3 x normal/mutual auth.
Validates WC_PENDING_E count >= 100 per test to confirm async crypto is exercised.
Static memory prints per-connection memory stats (peak mem, allocs, frees).
wolfcrypt/test/test.c updated with X25519 non-blocking test cases.
Tested: ./configure --enable-curve25519=small CFLAGS="-DWC_X25519_NONBLOCK" and ./configure CFLAGS="-DWC_X25519_NONBLOCK" --enable-curve25519=small --enable-asynccrypt.

ZD 21093

night1rider · 2026-02-03T22:22:08Z

Jenkins retest this please - CI issue PRB-Master-Job

dgarske · 2026-02-04T17:59:21Z

Jenkins retest this please

## Summary - Add non-blocking (incremental) Curve25519 key generation and shared secret via `WC_X25519_NONBLOCK`, modeled after the existing ECC non-blocking pattern (`WC_ECC_NONBLOCK`) - Implement `curve25519_nb()` and `fe_inv__distinct_nb()` in `fe_low_mem.c` as state-machine variants that return `FP_WOULDBLOCK` to yield after each field multiply - Add `wc_curve25519_set_nonblock()` API to attach/detach non-blocking context to a key - Integrate X25519 non-blocking with TLS 1.2/1.3 key share generation and shared secret in `tls.c` and `internal.c` (behind `WC_X25519_NONBLOCK && WOLFSSL_ASYNC_CRYPT_SW`) - Add `--enable-curve25519=nonblock` configure option (auto-enables `--enable-asynccrypt` and `--enable-asynccrypt-sw`) - Add X25519 async software dispatch cases in `async.c` and types in `async.h` - Fix async guard in `curve25519.c` to require `WOLFSSL_ASYNC_CRYPT_SW` (matching other algorithms) - Overhaul `examples/async/` client/server: non-blocking I/O via `WOLFSSL_USER_IO`, standalone `Makefile`, X25519/ECC mode selection, CI-friendly ready-file sync - Add `examples/configs/user_settings_curve25519nonblock.h` and CI coverage in `os-check.yml` and new `async-examples.yml` workflow - Add wolfcrypt test and API test coverage for X25519 non-blocking

…ion in SP ECC non-blocking.

dgarske · 2026-02-05T19:27:52Z

Jenkins retest this please: "EOFException"

Copilot

Pull request overview

This pull request adds non-blocking (async crypto) support for Curve25519 (X25519) key generation and shared secret operations, enabling WC_X25519_NONBLOCK for use with TLS. The implementation requires CURVE25519_SMALL and follows the existing WC_ECC_NONBLOCK pattern using an FP_WOULDBLOCK yield mechanism.

Changes:

Adds X25519 non-blocking API (wc_curve25519_set_nonblock) and implementation with state machine for iterative scalar multiplication in fe_low_mem.c
Integrates non-blocking X25519 into TLS layer for key share generation and ECDH operations during handshake
Fixes C90 mixed-declaration violations in SP ECC non-blocking code across multiple architecture files by moving typedef declarations before statements
Adds new standalone async TLS client/server examples with Makefile, user settings, and CI workflow
Updates ED25519 certificate keys to use proper PKCS#8 private key format instead of SubjectPublicKeyInfo

Reviewed changes

Copilot reviewed 37 out of 37 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
wolfssl/wolfcrypt/fe_operations.h	Declares non-blocking function prototypes for fe_inv and curve25519
wolfssl/wolfcrypt/curve25519.h	Defines non-blocking context structures and API
wolfssl/wolfcrypt/async.h	Adds X25519 async device support structures and markers
wolfcrypt/src/fe_low_mem.c	Implements non-blocking state machine for curve25519 scalar multiplication
wolfcrypt/src/curve25519.c	Adds non-blocking key gen and shared secret wrappers with async integration
wolfcrypt/src/async.c	Implements async device handlers for X25519 operations
wolfcrypt/test/test.c	Adds X25519 non-blocking test cases and updates existing tests for async support
src/tls.c	Integrates X25519 non-blocking support in key share generation and ECDH processing
src/internal.c	Allocates non-blocking contexts for X25519 keys and updates cleanup
src/ssl.c	Maps MP_WOULDBLOCK error to WC_PENDING_E
wolfcrypt/src/sp_*.c	Fixes C90 compliance by moving typedef before statements
tests/utils.c, tests/api.c	Handles MP_WOULDBLOCK errors in handshake loops
wolfcrypt/src/asn.c	Fixes non-blocking context allocation to only occur with valid async device
wolfssl/certs_test.h	Updates ED25519 keys to proper PKCS#8 private key format
gencertbuf.pl	Updates certificate paths to use -priv.der files
examples/async/*	New standalone async examples with user settings and Makefile
.github/workflows/async-examples.yml	CI workflow testing async examples with multiple configurations
configure.ac	Adds --enable-curve25519=nonblock option
examples/configs/user_settings_curve25519nonblock.h	Example configuration for X25519 non-blocking
.wolfssl_known_macro_extras	Adds NET_GETDEVRANDOM and WC_ASYNC_NO_X25519 macros

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Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dgarske · 2026-02-07T00:27:15Z

Jenkins retest this please "ChannelClosedException"

The non-blocking setup for X25519 and ECC in TLS was unconditionally setting up nbCtx, which caused functions to return FP_WOULDBLOCK. However, with INVALID_DEVID (the default), TLS has no async loop to handle FP_WOULDBLOCK, only WC_PENDING_E via the async framework. The fix follows the pattern used in asn.c: only set up nbCtx when the async device is active (devId != INVALID_DEVID). With INVALID_DEVID, the code now uses the blocking fallback (WC_ECC_NONBLOCK_ONLY) instead. This prevents unit test timeouts when built with --enable-curve25519=nonblock or --enable-ecc=nonblock. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

dgarske · 2026-02-09T18:38:24Z

Jenkins retest this please" FIPS v2 "RequestAbortedException"

dgarske self-assigned this Jan 29, 2026

dgarske force-pushed the x25519_nb branch from 3050cc4 to 07c9154 Compare January 29, 2026 19:58

dgarske marked this pull request as ready for review January 29, 2026 20:06

dgarske assigned wolfSSL-Bot Jan 29, 2026

dgarske force-pushed the x25519_nb branch 4 times, most recently from e8fc0a8 to 50dea8f Compare February 2, 2026 17:40

dgarske unassigned wolfSSL-Bot Feb 3, 2026

dgarske force-pushed the x25519_nb branch from 5814a8e to 3ee9f87 Compare February 4, 2026 17:18

dgarske added 2 commits February 4, 2026 21:28

Tests for mutual authentication

e9b711e

dgarske force-pushed the x25519_nb branch from 3ee9f87 to e9b711e Compare February 5, 2026 05:29

Add tests for async with static memory. Fix issue with mixed-declarat…

8c30cfb

…ion in SP ECC non-blocking.

dgarske changed the title ~~Support for Curve25519 non-blocking cryptography (based on PR #5764)~~ Add X25519 non-blocking support and async example improvements Feb 5, 2026

Fix for TLS with WOLFSSL_SMALL_CERT_VERIFY

78bba7e

dgarske requested a review from Copilot February 6, 2026 06:15

Copilot started reviewing on behalf of dgarske February 6, 2026 06:21 View session

Copilot AI reviewed Feb 6, 2026

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Peer review fixes

19bb719

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dgarske force-pushed the x25519_nb branch from 7df5bca to 19bb719 Compare February 6, 2026 18:27

dgarske assigned wolfSSL-Bot and unassigned wolfSSL-Bot Feb 7, 2026

dgarske assigned wolfSSL-Bot Feb 9, 2026

dgarske removed their assignment Feb 9, 2026

dgarske requested a review from SparkiDev February 9, 2026 20:51

SparkiDev requested changes Feb 10, 2026

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Comment thread src/internal.c

SparkiDev assigned dgarske Feb 10, 2026

Peer review improvements

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dgarske requested a review from SparkiDev February 11, 2026 16:37

dgarske removed their assignment Feb 11, 2026

SparkiDev approved these changes Feb 11, 2026

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SparkiDev self-assigned this Feb 11, 2026

SparkiDev merged commit 1847c6e into wolfSSL:master Feb 11, 2026
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Add X25519 non-blocking support and async example improvements#9721

Add X25519 non-blocking support and async example improvements#9721
SparkiDev merged 7 commits intowolfSSL:masterfrom
dgarske:x25519_nb

dgarske commented Jan 29, 2026 •

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Description

New Features

Fixes

Testing

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dgarske commented Jan 29, 2026 •

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