feat(tbor): implement SdSealingKeyGen (masked sealing key)

[vsonims]

Summary

Implement the firmware TBOR SdSealingKeyGen command (previously schema-only). Within an active Crypto-Officer session on an Initialized partition, it generates a fresh P-384 ECC sealing keypair for ECDH key agreement and returns the masked private key plus the public key. Maps to manticore CreateSDSealingKey -> ..., MaskedSDSealingKey.

The private key is not stored on the device: it is masked (AEAD-GCM-256) under the masking key associated with the requested KeyScope, and the masked blob is returned so the caller re-imports it (unmask-on-use) when the key is later needed. Because nothing is persisted, the command records no rollback (no undo-log dependency).

Handler (fw/core/lib/src/ddi/tbor/sd_sealing_key_gen.rs)

• Gate: Crypto-Officer-only (InvalidPermissions); session Active; partition Initialized (the scope masking keys are provisioned by PartFinal).
• Scope → masking key: Ephemeral → PartitionEphemeralMaskingKey, Local → PartitionLocalMaskingKey. Session and SecurityDomain (and any other) are rejected with the new UnsupportedKeyScope error until their masking keys exist (session-key masking / CreateSD's SDKMK).
• Generate the P-384 keypair (KeyAgreement PCT), mask the private scalar under the scope's key, and return (masked_key 180 B, pub_key 96 B). The SdSealing vault kind is retained as the masked blob's metadata key_kind; it is no longer stored.
• Structured into focused helpers: generate_sealing_keypair / mask_sealing_private_key / encode_sealing_response.

Schema + dispatch

• Response masked_key (180 B AEAD envelope) replaces key_handle in both the firmware and host crates; add MASKED_SEALING_KEY_LEN.
• Add HsmError::UnsupportedKeyScope (0x08700102) + TborStatus mirror.
• Wire SD_SEALING_KEY_GEN (0x09) into the opcode table, dispatcher, is_known_opcode / is_in_session / session-id cross-check classifiers.
• Add the SdSealing vault key kind (P-384 private) to the PAL traits enum, std PAL, and Uno key_vault length tables.

Tests + docs

• emu tests (ddi/tbor/types): happy-path roundtrip for Ephemeral + Local (distinct keypair per call, non-zero 180 B masked key + 96 B pub key), unsupported-scope reject (Session/SecurityDomain), before-finalize reject (InvalidArg), CU-session reject (InvalidPermissions), and default-PSK gate reject.
• Update docs/tbor-ddi/commands/sd_sealing_key_gen.md.

Notes

• Rebased onto current main (PartFinal feat(tbor): add PartFinal command handler (FinalizePart) #497 / SD schemas feat(tbor): Security-Domain command schemas (SdCreate/Reseal/Restore) #496 / key-masking are all merged); no undo-log (feat(undo): unified lock-free rollback for host commands #504) dependency.

Validation

• Full host workspace build + Uno firmware (thumbv7em) build.
• tbor-emu suite: 88/88 (7 SdSealingKeyGen tests).
• clippy -D warnings + nightly fmt clean.

[Copilot]

Pull request overview

Implements the firmware-side TBOR SdSealingKeyGen command (opcode 0x09) end-to-end across firmware, host types, docs, and emu tests. The command generates a fresh P-384 sealing keypair and returns a masked private key blob plus the public key (with scope-gated masking key selection), rather than persisting the private key on-device.

Changes:

• Add the firmware handler and wire the opcode into session control classification + TBOR dispatcher known/in-session/cross-check gates.
• Update TBOR schemas/host wrappers to return (masked_key[180], pub_key[96]) and introduce UnsupportedKeyScope status/error for unimplemented scope backing keys.
• Extend vault key-kind enums + key length tables (std PAL + Uno key_vault) and add emu integration tests and documentation updates.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
fw/core/lib/src/ddi/tbor/sd_sealing_key_gen.rs	New firmware handler that generates a P-384 keypair, masks the private scalar under a scope MK, and encodes the response.
fw/core/lib/src/ddi/tbor/mod.rs	Registers the new handler and classifies the opcode as known/in-session/needs session-id cross-check.
fw/core/lib/src/op.rs	Classifies SD_SEALING_KEY_GEN as SessionCtrl::InSession.
fw/pal/traits/src/error.rs	Adds HsmError::UnsupportedKeyScope for well-formed but not-yet-supported scopes.
ddi/tbor/types/src/status.rs	Adds TborStatus::UnsupportedKeyScope mirroring the new firmware error.
fw/core/ddi/tbor/types/src/sd_sealing_key_gen.rs	Updates firmware-side TBOR schema to return masked key + public key; exports pinned length consts and tests them.
ddi/tbor/types/src/sd_sealing_key_gen.rs	Updates host-side wrapper schema/response to return fixed-size masked key + public key arrays.
fw/pal/traits/src/vault.rs	Adds HsmVaultKeyKind::SdSealing and documents the sealing-key kind.
fw/plat/std/pal/src/drivers/vault.rs	Adds size mapping + tests for SdSealing (48-byte P-384 scalar).
fw/plat/uno/fw/crates/key_vault/src/kind.rs	Extends Uno key-kind length table + tests for SdSealing.
ddi/tbor/types/tests/commands/sd_sealing_key_gen.rs	Adds emulator integration tests covering happy paths, unsupported scopes, pre-finalize reject, CU reject, and default-PSK gate.
ddi/tbor/types/tests/commands/mod.rs	Exposes the new command test module.
docs/tbor-ddi/README.md	Marks SdSealingKeyGen as implemented (not schema-only).
docs/tbor-ddi/commands/sd_sealing_key_gen.md	Updates command documentation to match masked-key response and new gating/errors.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 4 comments.

[radutta99]

Looks good.

[vsonims]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved the merge conflict and merged origin/main into this branch in baf44c10.

[vsonims]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved the new merge conflicts and merged the current origin/main into this branch in c1b9b67.