feat(tbor): implement SdRestoreRemoteBackup (remote SD recovery)

[vsonims]

What

Implements SdRestoreRemoteBackup (opcode 0x0C, manticore §3.3.8) — the peer/migration recovery path for a security domain. It is SdResealRemoteBackup's HPKE-open front-end + SdRestoreLocalBackup's provisioning back-end.

Stacked on #566 (sd/restore-local-backup). Review/merge that first; this PR's diff is only the remote-restore delta.

Flow

1. Gate to a Crypto-Officer Active session on an Initialized partition; fail-fast one-shot (SdAlreadyInitialized).
2. Bind the caller policy to the partition policy_hash, then verify the sender evidence: cert chains validated + anchored to the policy SATA key, report v2 policy_hash == SHA-384(policy) → recover SndrPub.
3. Unmask masked_sealing_key → RcvrPriv (must be SdSealing); derive RcvrPub on-device.
4. HPKE-Auth-open src_remote_backup (sender-auth SndrPub) → BKS3.
5. reprovision_sd_from_bks3: recover SDMK from prev_sd_mk_backup, re-mask both backups at the current {svn, owner}, vault SDMK, mark the partition SD-initialized — undo-guarded. RcvrPriv, BKS3, SDMK, SDBMK are zeroized on every exit path.

Changes

• Handler fw/core/lib/src/ddi/tbor/sd_restore_remote_backup.rs (new).
• Wire schema reworked (was a stale placeholder): masked_sealing_key(180) · policy(484) · sender_evidence · src_remote_backup(161) · prev_sd_mk_backup(164, required). Host + fw schemas + round-trip unit tests.
• Shared back-end: extracted reprovision_sd_from_bks3 into sd_backup.rs (recover SDMK + anti-rollback + re-mask + vault-commit); refactored SdRestoreLocalBackup to reuse it — both restores now share one provisioning path.
• Dispatch wiring for 0x0C: mod.rs (dispatch arm + is_known_opcode/is_in_session/needs_session_id_cross_check) and op.rs from_tbor_opcode (required, else the SQE session-flag check rejects it as InvalidArg).
• Docs: full docs/tbor-ddi/commands/sd_restore_remote_backup.md + README table row (drops "schema-only").

Tests

New emu integration tests (ddi/tbor/types/tests/commands/sd_restore_remote_backup.rs):

• Round-trip — device 1 finalize + CreateSD → reboot → device 2 PartFinal(prev_local_mk_backup) restores PartLocalMK (so the captured sealing key unmasks) → HPKE-open restore returns non-zero refreshed local backups.
• One-shot — restore onto an already-initialized SD → SdAlreadyInitialized.
• Reject before finalize → InvalidArg.

Validation

• cargo xtask nextest --features emu -p azihsm_ddi_tbor_types → 113/113 pass (109 prior + 4 new, no regression).
• cargo xtask build -p azihsm_fw_hsm_std ✓ · uno cargo xtask clippy (core lib + uno PAL) ✓ · main cargo xtask clippy (full workspace) ✓.
• cargo +nightly fmt + cargo xtask copyright clean.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com
Copilot-Session: 0b09e50a-a9be-4bae-b347-d42dc775a258

[Copilot]

Pull request overview

Implements firmware + host support for TBOR SdRestoreRemoteBackup (opcode 0x0C), enabling security-domain recovery from a remote HPKE-authenticated backup by combining sender-evidence verification with the existing SD provisioning/restore mechanics.

Changes:

• Added the SdRestoreRemoteBackup handler, wired opcode/dispatch/session classification, and updated the wire schema to use masked_sealing_key, src_remote_backup, and required prev_sd_mk_backup.
• Refactored SD restore provisioning into a shared sd_backup::reprovision_sd_from_bks3 path, and updated local restore to reuse it.
• Added docs and emu integration tests for remote restore, plus minor test harness visibility adjustments.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
fw/core/lib/src/op.rs	Adds SD_RESTORE_REMOTE_BACKUP to the in-session opcode classification.
fw/core/lib/src/ddi/tbor/sd_restore_remote_backup.rs	New handler implementing remote SD restore: evidence verification + HPKE open + provisioning.
fw/core/lib/src/ddi/tbor/sd_restore_local_backup.rs	Refactors local restore to reuse the shared provisioning function.
fw/core/lib/src/ddi/tbor/sd_backup.rs	Extracts shared SD reprovisioning logic (reprovision_sd_from_bks3).
fw/core/lib/src/ddi/tbor/mod.rs	Wires new opcode constant, dispatch arm, and opcode classifiers.
fw/core/ddi/tbor/types/src/sd_restore_remote_backup.rs	Updates firmware-side TBOR wire schema and schema unit tests.
docs/tbor-ddi/README.md	Updates command table entry to reflect handler is implemented (not schema-only).
docs/tbor-ddi/commands/sd_restore_remote_backup.md	Adds full command documentation for remote restore flow, schema, and errors.
ddi/tbor/types/tests/commands/sd_restore_remote_backup.rs	Adds new emu integration tests for remote restore (round-trip, one-shot, pre-finalize reject).
ddi/tbor/types/tests/commands/sd_create_remote_backup.rs	Exposes evidence fields for reuse by remote restore tests.
ddi/tbor/types/tests/commands/mod.rs	Registers the new remote restore integration test module.
ddi/tbor/types/src/sd_restore_remote_backup.rs	Updates host-side request/response wrapper to match the new schema.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated no new comments.

The base branch was changed.