feat(tbor): implement SdCreate/RestorePeerBackup (peer SD cloning)

[vsonims]

What

Implements the security-domain peer-cloning command pair — SdCreatePeerBackup (opcode 0x0E, §3.3.10) and SdRestorePeerBackup (0x0F, §3.3.11) — gated by the SD policy's allow_peer_cloning flag.

Stacked on #567 (sd/restore-remote-backup). Review/merge that first; this PR's diff is only the peer-backup delta.

Both commands use masked SD-sealing keys (unmasked on-device via SdSealingKeyGen), not vault handles — matching the rest of the SD backup family. The stale schema-only stubs (key_id + a 180-byte pok_peer_backup) are reworked to masked_sealing_key and a 161-byte HPKE-Auth seal.

SdCreatePeerBackup (0x0E) — stateless

Recover BKS3 from the caller's pok_local_backup (unmask under PartLocalMK) and HPKE-Auth-seal it to a destination peer named by dst_evidence, authenticated by the sender's masked sealing key → pok_peer_backup (161 B). It is SdCreateRemoteBackup's seal front-end over a recovered (not minted) BKS3. Not one-shot and does not touch SDMK, so a rebooted partition can clone to a peer after PartFinal without first restoring the SD locally.

SdRestorePeerBackup (0x0F) — stateful, one-shot

= SdRestoreRemoteBackup + an allow_peer_cloning gate. HPKE-Auth-open pok_peer_backup with the masked receiver key (authenticated by the sender peer's attested key), then reprovision_sd_from_bks3(prev_sd_mk_backup) → device-local backups + vault SDMK + mark SD-initialized (undo-guarded).

Shared refactor

• Extracted recover_bks3_from_pok_local into sd_backup.rs (BKS3 unmask under PartLocalMK + SdPartitionOwnerSeed kind + anti-rollback); SdRestoreLocalBackup refactored to reuse it, and SdCreatePeerBackup shares it.
• New error HsmError::SdPeerCloningNotAllowed = 0x0870010A + TborStatus mirror.
• Opcodes 0x0E/0x0F wired through dispatch, op.rs from_tbor_opcode, and the mod.rs classifiers.

Tests

New emu integration tests (self-peer, sender == receiver):

• create-peer: self-seal round-trip (161-byte pok_peer_backup), reject-no-peer-cloning, reject-before-finalize.
• restore-peer: create-peer → reboot → PartFinal(prev_local_mk_backup) restores PartLocalMK → HPKE-open restore returns non-zero refreshed backups; one-shot (SdAlreadyInitialized); no-peer-cloning (SdPeerCloningNotAllowed); reject-before-finalize.

Validation

• cargo xtask nextest --features emu -p azihsm_ddi_tbor_types → 121/121 (114 prior + 7 new, no regression).
• cargo xtask build -p azihsm_fw_hsm_std ✓ · uno cargo xtask clippy ✓ · main cargo xtask clippy ✓ · fw types unit tests 35/35 ✓.
• cargo +nightly fmt + cargo xtask copyright clean.

Docs

Rewrites both command docs and the README table rows (drops "schema-only").

Note: this PR's base (#567) was amended to fix a latent sd_restore_remote_backup fw unit-test buffer overflow (1024→2048) that the non-main-targeting CI didn't surface.

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

[Copilot]

Pull request overview

This PR implements TBOR security-domain peer cloning by adding the SdCreatePeerBackup (0x0E) and SdRestorePeerBackup (0x0F) command pair, gated by the SD policy’s allow_peer_cloning flag, and aligns the wire schema/docs/tests accordingly.

Changes:

• Add firmware handlers for SdCreatePeerBackup (stateless HPKE-Auth seal of recovered BKS3) and SdRestorePeerBackup (stateful HPKE-Auth open + reprovision flow).
• Refactor shared SD-backup logic by extracting recover_bks3_from_pok_local into sd_backup.rs and reusing it from SdRestoreLocalBackup and SdCreatePeerBackup.
• Extend error/status surface and wiring: new SdPeerCloningNotAllowed error, opcode classification/dispatch, updated host wrappers, docs, and new emu integration tests.

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
fw/pal/traits/src/error.rs	Adds HsmError::SdPeerCloningNotAllowed for policy-gated peer cloning.
fw/core/lib/src/op.rs	Marks 0x0E/0x0F as InSession via SessionCtrl::from_tbor_opcode.
fw/core/lib/src/ddi/tbor/sd_create_peer_backup.rs	New handler: recover BKS3 from local backup and HPKE-Auth-seal to a peer (policy-gated).
fw/core/lib/src/ddi/tbor/sd_restore_peer_backup.rs	New handler: HPKE-Auth-open peer backup and reprovision SD (policy-gated, one-shot).
fw/core/lib/src/ddi/tbor/sd_restore_local_backup.rs	Refactors to reuse shared BKS3 recovery helper.
fw/core/lib/src/ddi/tbor/sd_backup.rs	Extracts shared recover_bks3_from_pok_local helper used by restore/local + create/peer.
fw/core/lib/src/ddi/tbor/mod.rs	Wires opcodes 0x0E/0x0F through module exports, dispatch, and opcode classifiers.
fw/core/ddi/tbor/types/src/sd_create_peer_backup.rs	Updates firmware-side wire schema for masked sealing key + HPKE peer backup (161B).
fw/core/ddi/tbor/types/src/sd_restore_peer_backup.rs	Updates firmware-side wire schema for masked sealing key + HPKE peer backup + prev_sd_mk_backup.
ddi/tbor/types/src/status.rs	Adds TborStatus::SdPeerCloningNotAllowed mirror status code.
ddi/tbor/types/src/sd_create_peer_backup.rs	Updates host-side wrapper types to match new schema (masked key + fixed-size peer backup).
ddi/tbor/types/src/sd_restore_peer_backup.rs	Updates host-side wrapper types to match new schema (masked key + fixed-size peer backup + prev backup).
ddi/tbor/types/tests/commands/mod.rs	Registers new integration test modules.
ddi/tbor/types/tests/commands/sd_create_peer_backup.rs	New emu integration tests for create-peer (roundtrip + policy/lifecycle rejects).
ddi/tbor/types/tests/commands/sd_restore_peer_backup.rs	New emu integration tests for restore-peer (roundtrip + one-shot + policy/lifecycle rejects).
docs/tbor-ddi/README.md	Updates command table rows to remove “schema-only” for 0x0E/0x0F.
docs/tbor-ddi/commands/sd_create_peer_backup.md	Rewrites command documentation to reflect the implemented handler and updated schema/flow.
docs/tbor-ddi/commands/sd_restore_peer_backup.md	Rewrites command documentation to reflect the implemented handler and updated schema/flow.

[Copilot]

Pull request overview

Copilot reviewed 18 out of 18 changed files in this pull request and generated no new comments.

The base branch was changed.