Translate the key wrap metadata trailer

[yosuke-wolfssl]

Problem

The key wrap protocol carries a whNvmMetadata as a raw struct trailer
after the fixed request/response headers, but the server translated only the
headers. whNvmMetadata is four uint16_t fields (id, access, flags,
len), so every one is byte-swapped for a cross-endian client/server pair:

Path	Trailer	Symptom for a swapped client
WH_KEY_KEYWRAP request	whNvmMetadata + key	id 0x4025 (TYPE=WRAPPED) read as 0x2540 (TYPE=SHE) → valid wrap rejected WH_ERROR_BADARGS
WH_KEY_KEYUNWRAPEXPORT response	whNvmMetadata + key	id, access, flags, len returned byte-swapped

Every other NVM message flattens the struct into message fields and translates
each one; key wrap is the only place the raw struct crosses the boundary.

Addressed by f_5469.

Fix (src/wh_server_keystore.c)

Server-side only: clients always send native byte order, and the server
translates both directions from the comm-header magic.

• wh_MessageNvm_TranslateMetadata() — new helper in wh_message_nvm.[ch],
  in-place safe, label copied verbatim.
• _HandleKeyWrapRequest translates on ingress before any field is
  inspected, establishing the invariant that blobs always store metadata in
  server-native order.
• _HandleKeyUnwrapAndExportRequest translates on egress last, after every
  policy check has run on native values.

Both handlers are static with one call site each, so they gain a magic
parameter. No client, wire-format, or struct change.

Also fixed, found while auditing the failure paths: *out_resp_size for
KEYUNWRAPEXPORT unconditionally counts a whNvmMetadata trailer, so a failed
unwrap shipped up to 32 bytes of stale comm-buffer content to the client. The
handler now zeroes the trailer and any decrypted key with wh_Utils_ForceZero()
on every failure exit, and the dispatcher scrubs as a backstop. In-switch
returns became ret = X; break; so one epilogue covers them all.
_HandleKeyWrapRequest also sets resp->cipherType before its first failure
exit — the client checks cipherType ahead of rc, so an early return
previously surfaced as WH_ERROR_ABORTED instead of the real error.

Tests

Reworked on review: 1,179 test lines removed, 128 added. Both original
files were shapes a real peer cannot produce — wh_test_keywrap_endian.c (720)
drove whServerContext* internals with synthetic magics, and
wh_test_keywrap_endian_e2e.c (459) hand-built packets and pushed them at the
transport, because wh_CommClient only ever sends native magic. Their two
wh_test_list.c entries and the README.md coverage-gap bullet go with them.

Replaced by test-refactor/misc/wh_test_message_nvm.c, following #468: a
loopback pair structurally cannot observe a byte-order bug, so the test calls
wh_MessageNvm_TranslateMetadata() directly with WH_COMM_MAGIC_SWAP. No
packet crafting, no new entry point registered beyond the one parent function.
It asserts native magic is a no-op, all four scalars swap, the label byte
array does not move, translation is its own inverse, in-place (src == dest)
matches out-of-place, and NULL args give WH_ERROR_BADARGS. Expected values are
written out as literals rather than derived from wh_Translate16(), so the
oracle does not share the code under test. The helper is ungated, so the test
runs in every configuration.

The whNvmMetadata entry added to wh_test_check_struct_padding.c stays — it
is what keeps the raw wire struct padding-free.

Coverage dropped with the harness, none of it reachable from a real client:
foreign-magic acceptance at the comm layer, the req_packet/resp_packet
aliasing that makes egress translation an in-place swap, wrap/unwrap policy
negatives already covered by client-server/wh_test_keywrap.c, and the
malformed-request residue check for the scrub described above. The new
"keep in step with wh_MessageNvm_TranslateAddObjectRequest" comment likewise
has no test behind it; the twin is pre-existing code this PR does not touch.

Verification

On merge base 237bfbc, clean under -std=c90 -Werror -Wall -Wextra, zero
warnings in all four configurations:

Config	Result
test-refactor default	46 passed / 26 skipped / 0 failed of 72
test-refactor DMA=1	50/22/0
test-refactor SHE=1	52/20/0
test-refactor NOCRYPTO=1	17/55/0

whTest_MessageNvmTranslate passes in all four. Two negative controls, each
rebuilt and re-run: dropping the access WH_T16 fails the test, and dropping
the label memcpy fails it; restoring both returns 46/26/0.

[Copilot]

Pull request overview

This PR fixes cross-endian interoperability for the key-wrap protocol by translating the whNvmMetadata “raw struct trailer” that follows the fixed key-wrap request/response headers. It introduces a dedicated metadata translation helper and applies it in the server handlers so policy checks and storage always operate on native-order metadata, while the wire-facing trailer is translated appropriately.

Changes:

• Add wh_MessageNvm_TranslateMetadata() to translate whNvmMetadata trailers (including in-place translation support).
• Update key wrap / unwrap-and-export server handlers to translate the metadata trailer on ingress/egress based on the request magic.
• Add a dedicated endianness regression test for key-wrap metadata trailers and register it in the server test list.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
wolfhsm/wh_message_nvm.h	Declares the new wh_MessageNvm_TranslateMetadata() helper for raw-struct metadata trailers.
src/wh_message_nvm.c	Implements wh_MessageNvm_TranslateMetadata() using existing translation macros and label passthrough.
src/wh_server_keystore.c	Translates key-wrap metadata trailer on request ingest and on unwrap-and-export response egress using magic.
test-refactor/server/wh_test_keywrap_endian.c	Adds endianness coverage: helper property checks plus wrap→unwrap/export round-trips under native/swapped magic.
test-refactor/wh_test_list.c	Registers the new whTest_KeyWrapEndian server test.

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[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #472

Scan targets checked: wolfhsm-core-bugs, wolfhsm-crypto-bugs, wolfhsm-src

No new issues found in the changed files. ✅

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #472

Scan targets checked: wolfhsm-core-bugs, wolfhsm-crypto-bugs, wolfhsm-src

No new issues found in the changed files. ✅

[yosuke-wolfssl]

Hello @AlexLanzano ,
I fixed issues you mentioned with some additional stuff I found during rework.
The PR description is also updated accordingly.
Could you review this again ?

[AlexLanzano]

@yosuke-wolfssl Looks like you have some failing test cases with your new changes? Could you take a look?

[AlexLanzano]

Looks good. Passing off to you @bigbrett