Add crypto callback only mode for ed25519

[padelsbach]

Description

Expand existing ed25519 crypto callback to support the "only" mode which strips the software implementation for use with HSM or other hardware accelerators.

make_key, sign_msg and verify_msg supported. No streaming support.

Testing

Added unit test and updated CI workflow

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[padelsbach]

Semi-related change to add these missing guards. The cb find mechanism would have failed here.

[padelsbach]

Jenkins retest this please

[github-actions]

retest this please

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #10830

Scan targets checked: wolfcrypt-bugs, wolfcrypt-rs-bugs, wolfcrypt-src, wolfssl-bugs, wolfssl-src

No new issues found in the changed files. ✅

[github-actions]

MemBrowse Memory Report

stm32-sim-stm32h753

• FLASH: .text +64 B (+0.0%, 183,140 B / 2,097,152 B, total: 9% used)
  No memory changes detected for:
• gcc-arm-cortex-m0plus
• gcc-arm-cortex-m3
• gcc-arm-cortex-m4
• gcc-arm-cortex-m4-baremetal
• gcc-arm-cortex-m4-crypto-only
• gcc-arm-cortex-m4-dtls13
• gcc-arm-cortex-m4-min-ecc
• gcc-arm-cortex-m4-openssl-compat
• gcc-arm-cortex-m4-pkcs7
• gcc-arm-cortex-m4-pq
• gcc-arm-cortex-m4-rsa-only
• gcc-arm-cortex-m4-sp-math
• gcc-arm-cortex-m4-tls12
• gcc-arm-cortex-m4-tls13
• gcc-arm-cortex-m7
• gcc-arm-cortex-m7-pq
• gcc-arm-cortex-m7-tls13
• linuxkm-pie
• linuxkm-standard

[padelsbach]

jenkins retest this please

[rizlik]

Great work, but the problem is that make_public and check-key survives and so ge_operations can't be removed from the build.
Given that the main goal of ONLY_ED25519 is to reduce code/data size, we should aim at removing all the software math.

I see two options:

1. Gating out the make_public and check_key with new gating macros
2. Adding two crypto callbacks for make_public and check_key

[rizlik]

To me it looks like that the priv check must be inside the software blocks, not outside. So this is a bug that predate the PR. Probably a good idea to move it inside that software block instead of gating on !ONLY_ED25519, or just ignore it in this PR.

[Frauschi]

🐺 Skoll Code Review

Overall recommendation: COMMENT
Findings: 1 total — 1 posted, 0 skipped

Posted findings

• [Low] Sign CB_ONLY path omits (void)ed25519Ctx suppression present in verify path — wolfcrypt/src/ed25519.c:445

Review generated by Skoll via Claude/Codex

[Frauschi]

🔵 [Low] Sign CB_ONLY path omits (void)ed25519Ctx suppression present in verify path
🔧 NIT convention

The WOLF_CRYPTO_CB_ONLY_ED25519 branch of wc_ed25519_verify_msg_ex adds (void)ed25519Ctx; to suppress an unused-const-variable warning, but the equivalent WOLF_CRYPTO_CB_ONLY_ED25519 branch of wc_ed25519_sign_msg_ex does not. ed25519Ctx is defined whenever HAVE_ED25519_SIGN || HAVE_ED25519_VERIFY. In a narrow configuration built with HAVE_ED25519_SIGN but without HAVE_ED25519_VERIFY under WOLF_CRYPTO_CB_ONLY_ED25519, ed25519Ctx is never referenced (both the sign software path and the streaming-verify code that use it are compiled out), which can trigger -Wunused-const-variable under -Werror. The default/CI configs enable both sign and verify, so this does not fire in the added CI job.

Recommendation: For symmetry with the verify branch and to avoid a possible unused-const warning in sign-only configurations, add (void)ed25519Ctx; at the top of the sign CB_ONLY branch.