Zeroizations, code reinforcements, ECC key size fixes

[danielinux]

F/845 - Variable shadowing cleanup in psa_copy_key (4647472)
F/857 - Reject wrapped AEAD multipart lengths (024cf0d)
F/856 - Zero key agreement secrets before free (436714a)
F/855 - Zero ECDH secret before free (a4f407d)
F/854 - Zero derived key buffer before free (3772e4d)
F/853 - Scrub PBKDF2 CMAC stack buffers (2138fbf)
F/852 - Scrub TLS 1.2 PSK premaster buffer (f35207c)
F/851 - Zero HKDF PRK stack buffer (4ff8496)
F/850 - Zero DES3 expanded keys after setup (f1d0585)
F/846 - Reject oversized PSA random requests (cecfc2a)
F/844 - Fix ECC key bit inference for non-byte-aligned curves (c48ec68)
F/843 - Fix ECC curve IDs for 192-bit and 224-bit curves (454e830)
F/849 - Zeroize generated keys after import (19d7da8)
F/848 - Zeroize volatile keys on destroy (f1e9958)
F/847 - Zeroize key data before freeing (aec0647)

[Copilot]

Pull request overview

This PR hardens wolfPSA’s crypto/key-handling by adding systematic zeroization of sensitive buffers, tightening length validation to prevent overflows/wraps, and fixing ECC curve/key-size inference for non-byte-aligned curves.

Changes:

• Replace key-data frees with a new zeroizing free routine and add explicit scrubbing for multiple secret-bearing buffers (KDF, key agreement, key generation, volatile key storage, DES3 expanded keys).
• Reject oversized RNG requests and reject AEAD multipart accumulated-length wraparounds.
• Fix ECC curve ID selection for 192/224-bit curves and correct ECC key-bit inference for 521-bit curves; add targeted tests and CI wiring for ECC tests.

Reviewed changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
wolfpsa/psa_key_storage.h	Renames the public key-data free API to a force-zeroing variant.
src/psa_key_storage.c	Adds ECC bit inference mapping and widespread key buffer scrubbing (volatile keys, generated keys, exports/copy).
src/psa_key_derivation.c	Scrubs HKDF PRK, TLS1.2 PSK premaster, PBKDF2-CMAC stack buffers, and key-agreement secrets.
src/psa_asymmetric_api.c	Scrubs ECDH/key-agreement secret buffers before free.
src/psa_cipher.c	Scrubs DES3 expanded key material on stack and key_data on free paths.
src/psa_mac.c	Uses zeroizing free for key buffers across validation/setup error paths.
src/psa_aead.c	Adds overflow-safe accumulated-length checks for multipart AEAD update paths.
src/psa_asymmetric.c	Corrects curve ID mapping for 192/224-bit curves with feature guards.
src/psa_random.c	Rejects psa_generate_random() sizes larger than UINT32_MAX.
test/psa_server/psa_random_size_test.c	New test exercising oversized RNG request rejection.
test/psa_server/psa_ecc_curve_id_test.c	New test verifying ECC curve ID mapping for 192/224-bit curves.
test/psa_server/psa_ecc_bit_inference_test.c	New test verifying 521-bit ECC key-size inference for pub/priv imports.
test/psa_server/psa_des3_stack_scrub_test.c	New smoke test for DES3 setup/abort path.
test/psa_server/psa_api_test.c	Adds AEAD multipart length wraparound regression test.
test/Makefile	Builds new test binaries; links curve-id test with internal objects.
.github/workflows/test-psa-api.yml	Builds/runs ECC-focused new tests in CI.
.gitignore	Ignores newly built test binaries.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.

[Copilot]

Pull request overview

This PR hardens wolfPSA’s cryptographic handling by adding comprehensive zeroization on key/secret buffers, tightening input length validation (random and AEAD multipart), and correcting ECC curve ID/bit-size inference (including non-byte-aligned curves).

Changes:

• Replace key-data free paths with forced-zeroization and scrub additional sensitive stack/heap buffers across MAC/cipher/derivation/asymmetric/key storage flows.
• Add overflow/oversize validation for PSA random generation and AEAD multipart length accumulation.
• Fix ECC curve ID selection for 192/224-bit curves and improve ECC key bit inference; add corresponding regression tests and CI steps.

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
wolfpsa/psa_key_storage.h	Updates key-data free API to support zeroization with length.
src/psa_key_storage.c	Adds ECC bit inference mapping, zeroizes volatile key material and generated/import buffers, implements forcezero-free helper.
src/psa_key_derivation.c	Scrubs HKDF PRK, TLS12 premaster, PBKDF2 CMAC intermediates, and zeroizes key agreement secrets.
src/psa_cipher.c	Zeroizes DES3 expanded key material and forcezero-frees key buffers in error/cleanup paths.
src/psa_mac.c	Forcezero-frees key buffers across MAC validation/setup error paths.
src/psa_asymmetric_api.c	Forcezero-frees key buffers and zeroizes ECDH/key agreement secret buffers on failure/success paths.
src/psa_asymmetric.c	Corrects ECC curve IDs for 192/224-bit curves with feature guards.
src/psa_random.c	Rejects oversized random requests (> UINT32_MAX).
src/psa_aead.c	Moves AEAD ctx definition to internal header and rejects wrapped multipart accumulated lengths.
src/psa_aead_internal.h	Introduces internal AEAD ctx accessor for tests/internal use.
test/psa_server/psa_api_test.c	Adds regression test for AEAD multipart accumulated-length wrap rejection.
test/psa_server/psa_random_size_test.c	New test ensuring oversized random requests are rejected.
test/psa_server/psa_ecc_curve_id_test.c	New test validating ECC curve IDs for 192/224-bit secp r1/k1.
test/psa_server/psa_ecc_bit_inference_test.c	New test validating ECC bit inference for P-521 sized material.
test/psa_server/psa_des3_stack_scrub_test.c	New test covering DES3 setup path (for scrub behavior).
test/Makefile	Builds new test binaries and adds include path for internal header usage.
.github/workflows/test-psa-api.yml	Builds and runs the new tests in CI.
.gitignore	Ignores newly built test binaries.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.