[JacobBarthelmeh]

F-13114

[Copilot]

🟡 Changes recommended

Successful START/FINISH-only calls leave output lengths unchanged despite producing no bytes, risking stale-buffer consumption, and the README contradicts the new length-handling contract.

2 open issues

• Zero output length for successful calls without UPDATE · New
• Update README to document output-length and E_SMALL_BUFFER behavior · New

What changed in this PR

This PR updates wolfCrypt’s AUTOSAR AES-CBC services to treat output length as an input capacity and return the number of bytes produced.

Changes:

• Validate output buffers and length pointers, rejecting insufficient capacity.
• Report the output length after successful CBC processing.
• Update tests to supply buffer capacities and check returned lengths and invalid inputs.

File	Description
wolfcrypt/​src/​port/​autosar/​test.c	Supplies output capacities and adds length and error assertions.
wolfcrypt/​src/​port/​autosar/​crypto.c	Validates CBC output capacity, reports produced length, and updates a CMAC comment.

_{Review effort: Balanced}

[github-actions]

MemBrowse Memory Report · Explore what changed →

zephyr-frdm_rw612

• FLASH: log_const_area -8 B, rodata -8 B, text +1,592 B (+0.6%, 284,040 B / 67,108,864 B, total: 0% 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
• stm32-sim-stm32h753

---

_{Catch memory regressions in CI with MemBrowse. Free for open source.}

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11995

Scan targets checked: wolfcrypt-port-bugs
Not reviewed (no scan target covers them): wolfcrypt/src/port/autosar/README.md
Coverage: 1 of 2 in-scope changed file(s) opened by the reviewer; not opened: wolfcrypt/src/port/autosar/test.c

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

This review was generated automatically by Fenrir. Reported findings require changes before merge.

Review tier: Lite

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11995

Scan targets checked: wolfcrypt-port-bugs
Not reviewed (no scan target covers them): wolfcrypt/src/port/autosar/README.md
Coverage: 2 of 2 in-scope changed file(s) opened by the reviewer

Fenrir result: Approved ✅

No new issues found in the changed files.

Advisory only — this automated result does not count as a GitHub approval.

Review tier: Lite

Fenrir's latest completed scan found no issues; clearing the prior automated change request.