Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[0.48.0] - 2026-04-17

Changed

• Secure crypto: central allowlist check in derive_domain_key() and derive_leb_key() — all domains and both read/write paths validated before key derivation.

• Secure backend: monotonic AEAD counters for EC and device-header domains — recovered from flash during init, incremented per write.

• Secure backend: VID counter overflow check (COUNTER_MAX) with KEY_ROTATE_NOW event.

• Secure backend: overflow guards in ec_hdr_write, vid_hdr_write, and res_peb_commit.

• Secure backend: eager reserved-PEB key upgrade during attach — when requested_write_key_version differs from flash, res_peb_commit rewrites device and volume headers under the new key immediately, with graceful fallback if the key is not yet provisioned.

• Secure backend: reserved-PEB refcount tracking via reserved_key_version field — KEY_RETIRABLE blocked while reserved PEBs still depend on old key version.

Added

• Test: VID counter floor survives remove→create→reboot sequence (2 cycles).

• Test: refcount E2E lifecycle with key rotation (kv=1→kv=2), volume ops, unmap, resize, erase cycles, and KEY_RETIRABLE verification.

• Tests: counter overflow boundary tests for EC, VID, and reserved-PEB AEAD counters.

• Tests: allowlist rejection tests for derive_domain_key and derive_leb_key.

[0.47.0] - 2026-04-17

Changed

• Plain backend: renamed 7 .c and 2 .h files to ubi_plain_* prefix; updated all includes and CMake.

• Secure backend: replaced ubi_secure_zeroize volatile-loop with mbedtls_platform_zeroize.

• Secure backend: added LOG_ERR to silent error returns in volume, LEB, runtime, and crypto modules.

• Secure backend: removed § references from comments; fixed ubi_secure_anchor_create section label.

• Tests: normalized section divider comments to 100-char centered format.

[0.46.0] - 2026-04-17

Added

• Secure error-handling test suite (74 tests): device init/deinit, volume CRUD, LEB I/O, resize, and edge-case contract enforcement mirrored from the plain backend.

• Secure fault-injection test suite (2 tests): transactional safety under allocation failures and overwrite faults.

• Secure mutation-gate test suite (1 test): write-shutdown gate enforcement via ubi_test_set_write_shutdown().

• Secure vol-id-watermark test suite (3 tests): persistent volume-ID high-watermark across remove, reinit, and slot re-indexing.

[0.45.0] - 2026-04-16

Changed

• Documentation aligned with secure backend implementation: updated flash footprint, struct sizes, test counts, coverage numbers, and Kconfig reference across all docs.

• Merged README Design Trade-offs into Key Properties; added authenticated encryption and dynamic resize entries.

• Removed completed crypto layer from roadmap (only shell commands remain as planned).

Fixed

• CI format-check: clang-format version-dependent goto label formatting resolved with off/on guards.

• CI cross-build nRF5340 secure: added test random generator for builds without BLE IPC.

• CI cross-build STM32U5 secure: ubi_device size BUILD_ASSERT guarded for ARM vs POSIX k_mutex layout difference.

[0.44.0] - 2026-04-16

Added

• Forensic scan test suite (5 tests): verifies no plaintext data, volume names, or key material appear on flash after secure writes.

• Host-side Python forensic scanner and test docblock checker scripts.

• CI jobs: format-check, forensic-scan, cross-build secure dimension for STM32U5 and nRF5340.

• Init-time anchor re-creation: orphaned volumes automatically get a new hidden anchor at attach.

Changed

• Test and coverage scripts accept mode parameter (plain/secure/chunked).

[0.43.0] - 2026-04-16

Added

• Chunked secure LEB mode: LEB records split into independently authenticated chunks for partial-read support. Configurable chunk size (256-65536 B).

• Chunked partial-read authentication: only touched chunks are verified, reducing read latency and RAM.

• Chunked geometry validation at init and budget accounting for chunked writes.

• Secure recovery test suite (8 tests): interrupted writes, anchor rewrites, reserved PEB commit faults, generation replay rejection.

• Flash write fault injection wired into the secure backend.

[0.42.0] - 2026-04-15

Added

• Sticky crypto read-only mode: event callback can escalate to device-wide write block (-EROFS); reads remain functional.

• Security event infrastructure: 10 event types (AUTH_FAILURE, FORMAT_VIOLATION, KEY_ROTATE_SOON/NOW, KEY_RETIRABLE, RNG_FAILURE, etc.) delivered through application callback.

• Freshness sync after every commit-visible mutation with configurable cadence.

• Key-version PEB refcount tracking with KEY_RETIRABLE signalling when a key version is fully erased.

• LEB usage budget tracking with soft/hard thresholds and pre-write rejection.

• Read-path key-version allowlist enforcement.

• Sensitive buffer zeroization (compiler-safe volatile memset).

• Runtime policy test suite (15 tests): read-only transitions, event escalation, budget thresholds, key retirement, allowlist rejection, mixed-key rotation.

[0.41.0] - 2026-04-15

Added

• Hidden per-volume anchor PEBs: each secure volume reserves one internal PEB preserving monotonic counter state across unmap, shrink, and erase.

• VID-domain counter floor: monotonic VID counter persisted in secure device header, reconstructed at attach.

• Last-writable-witness check: erase path rewrites anchor before erasing the last carrier of a volume’s counter floor.

• Emergency free-PEB reserve: write path reclaims a dirty PEB before consuming the last free PEB.

Changed

• Volume create rolls back on anchor allocation failure.

• Tests updated for anchor PEB overhead and wear-leveling participation.

• New docs: secure volume lifecycle and secure recovery scenarios.

[0.40.0] - 2026-04-15

Added

• Complete secure data-PEB runtime: volume create/resize/remove, LEB write/read/map/unmap, erase — all with authenticated encryption.

• Data-PEB scan pipeline: classifies PEBs into free/dirty/bad pools with full AEAD verification.

• Secure parity test suites (26 tests across 7 suites): functional parity with plain backend on encrypted flash.

• Flash geometry overlays for nRF5340 (4 KB erase) and STM32U5 (8 KB erase) on native_sim.

• Multi-geometry CI: tests run against three flash geometries (default, nRF5340, STM32U5).

Fixed

• LEB write/nonce counters recovered from existing VID header (were hardcoded to 0).

• Write-block alignment padding for secure ciphertext+tag buffer.

• Missing bad-block torture and degraded-mode recovery in secure runtime.

• Geometry validation for erase/write block alignment.

[0.39.0] - 2026-04-14

Added

• Secure data-PEB I/O: authenticated read/write for EC headers, VID headers, and LEB data in single-tag mode.

• Domain-separated AAD serialization for all record types.

Changed

• Key derivation centralized; parent authentication passed via typed context structs.

[0.38.0] - 2026-04-15

Added

• Secure reserved-PEB attach path: format-on-blank, attach-to-existing, mode mismatch detection.

• PSA Crypto integration: HKDF-SHA-256 key derivation, AES-128-CCM AEAD, salt generation.

• Encrypted dual-bank reserved PEB commit and authentication.

• Secure attach test suite (8 tests): format, re-attach, mode mismatch, freshness rejection, callback validation.

[0.37.0] - 2026-04-14

Added

• Secure public API types: crypto config, event types (tagged union), freshness descriptor, policy struct, and callback typedefs.

• Secure Kconfig surface: master enable, budget limits, rotation thresholds, chunked mode, PEB cache, freshness sync, strict RO policies.

• Crypto fault injection hooks (7 stages) for integration tests.

• Secure test profiles and board configs with Mbed TLS PSA.

[0.36.0] - 2026-04-14

Changed

• Full backend ops dispatch: all public API functions route through a vtable (11 ops). Plain backend functions renamed to ubi_plain_*.

• Internal headers decoupled from plain-specific includes, making them backend-agnostic.

[0.35.0] - 2026-04-14

Changed

• Unified init API: ubi_device_init(mtd, crypto_cfg, &ubi). Passing NULL selects plain; non-NULL selects secure. Runtime backend dispatch via ops vtable.

[0.34.0] - 2026-04-13

Changed

• Secure architecture spec: per-device runtime mode selection (not per-build), tagged-union events, check_freshness confirmed as attach-time only.

• Repository layout split into common/, plain/, secure/ namespaces for library and test sources.

• Format script made recursive with --check mode for CI.

[0.33.0] - 2026-04-11

Changed

• design_proposal_crypto.md promoted to secure_architecture.md as a first-class architecture document.

• architecture.md renamed to plain_architecture.md.

• All doc navigation updated for the new names.

[0.32.0] - 2026-04-11

Changed

• Secure architecture spec rewrite (v6): hidden per-volume anchor PEBs, secure device header with crypto metadata, full counter continuity framework, renamed child keys to domain names, simplified chunked mode (no per-chunk subkeys), expanded write-budget enforcement, precise AAD byte layouts for all record types, tagged-union events with verdicts.

[0.31.0] - 2026-04-10

Changed

• Secure architecture spec rewrite (v5): mode detection rules, normative KDF labels, single-tag CCM payload limit, zero-length LEB encoding, tail-padding rules, parent EC key_version in VID and LEB AAD, release checklist (Appendix C).

[0.30.0] - 2026-04-09

Added

• “Why UBI for Zephyr” positioning document: gap analysis, comparison with FCB/NVS/ZMS/LittleFS.

Changed

• Secure architecture spec rewrite (v4): plain-core baseline assumptions, application boundary clarification, expanded key derivation and freshness-sync.

[0.29.0] - 2026-04-09

Added

• Persistent vol_id high-watermark: volume IDs are never reused across the device lifetime. Overflow returns -ENOSPC.

• Test suite (4 tests): reuse prevention, cross-reboot persistence, slot stability, overflow.

Changed

• Volume matching by vol_id instead of positional index; re-index loop eliminated.

[0.28.0] - 2026-04-09

Added

• Central mutation gate: per-device read-only flag checked before every public mutator. Three mutation classes (reserved metadata, data path, maintenance).

• Runtime degradation detection and self-healing via reserved PEB bank recovery.

• Test-only write-shutdown API.

• Test suite (5 tests): write-shutdown, degradation, transparent recovery, bank recovery.

[0.27.0] - 2026-04-10

Changed

• Data PEB commit order changed to EC -> DATA -> VID. VID header is now the sole commit-visible record.

• Init scan distinguishes free PEBs from uncommitted writes by probing the data area.

Fixed

• Uncommitted writes were misclassified as free under the new write order.

[0.26.0] - 2026-04-09

Changed

• Erased-state detection uses hardware-reported erase value instead of hardcoded 0xFF.

[0.25.0] - 2026-04-08

Changed

• Secure architecture spec rewrite (v3): init classification, write/read/erase paths, key lifecycle with refcount retirement, events and policy, cost model, illustrative API (Appendix A).

[0.24.0] - 2026-04-03

Added

• Secure architecture design proposal (v2): AES-128-CCM for all on-flash structures, ESSIV nonces, per-domain key derivation, anti-rollback, crash-safe key rotation, external AAD callback.

[0.23.0] - 2026-04-03

Added

• nRF5340 DK board support (64 KB UBI partition, 4 KB erase blocks).

Changed

• CI split into parallel jobs: native-tests, cross-build, coverage.

• Concurrency control, least-privilege permissions, path filters, SHA-pinned actions.

[0.22.0] - 2026-04-02

Added

• Flash I/O fault injection: controllable write and erase failures.

• Test suite ubi_io_faults (24 tests): flash I/O and malloc fault sweeps.

• Test suite ubi_init_errors (33 tests): geometry validation, partition guard, format/header corruption at init.

• 34 new error-handling tests and 6 new recovery tests.

• Long-term EC counter equality test (500 cycles, max deviation <= 2).

[0.21.1] - 2026-04-02

Fixed

• Sphinx -W flag: warnings now fail the doc build.

• Breathe + Doxygen 1.9.8 compatibility: switched to doxygengroup directives.

[0.21.0] - 2026-04-02

Added

• Static memory backend (default): all allocations via k_mem_slab pools instead of global heap.

• Memory abstraction layer with Kconfig-selectable backend (static/heap).

• Init-time validation: static backend verifies flash geometry fits configured pools.

• Dual-backend CI runs.

Changed

• PEB tracking items share a union for in-place retyping during state transitions.

• Fault injection routed through memory abstraction layer.

[0.20.1] - 2026-04-02

Changed

• Removed read-write lock from roadmap (per-device mutex is sufficient).

• Renamed “User-space tools” to “Shell commands” in roadmap.

Fixed

• Test API functions visible in Doxygen output.

[0.20.0] - 2026-04-01

Added

• Single-handle-per-partition guard: prevents two device handles for the same flash partition.

• Concurrency test suite (5 tests): multi-threaded readers/writers, deinit quiescence, double-init guard.

Fixed

• ubi_device_deinit() acquires mutex before teardown, preventing races with in-flight operations.

[0.19.0] - 2026-04-01

Added

• Volume config validation, device/volume header semantic checks.

• Invariant checker API for tests.

• Allocation fault injection via Kconfig.

• Shared test fixtures and raw flash write helpers.

Changed

• Transactional ubi_volume_create() and shrink: RAM state consistent with flash on failure.

• Copy-on-write leb_write(): old mapping preserved until new PEB is fully written.

• ubi_leb_unmap() is idempotent; ubi_leb_map() is a no-op when already mapped.

Fixed

• PEB tracking loss on allocation failure during bad-block handling.

[0.18.0] - 2026-04-01

Added

• Overview doc with mental model, six-step lifecycle, and Mermaid diagrams.

• Architecture guide expanded: core invariants, Mermaid flowcharts, degraded-mode table.

Changed

• README rewritten as landing page with stack diagram, key properties, quality metrics.

• All doc pages restructured with “what this page covers” framing.

[0.17.1] - 2026-03-31

Fixed

• Doc source file table and test counts aligned with Phase 3 file splits.

• Sample app expanded to demonstrate full lifecycle.

Changed

• Removed per-file Doxygen version/date tags; replaced Yoda conditions with idiomatic style.

[0.17.0] - 2026-03-31

Changed

• Split ubi_core.c into init and runtime modules; split ubi_io.c into metadata and data modules. No functional changes.

[0.16.0] - 2026-03-31

Added

• read_only_degraded exposed in device info struct.

• Cached geometry in device struct (no flash I/O for get_info()).

• Thread-safety notes and precise \retval docs on all public functions.

Changed

• allocated_peb_count renamed to reserved_peb_count.

• -EROFS propagated from degraded reserved PEB scan through init and mutators.

[0.15.0] - 2026-03-31

Added

• Volume name validation helpers (bounded, NUL-safe).

• Semantic validation of on-flash device headers.

• Flash geometry validation at init.

Fixed

• Eliminated strlen() on raw flash fields (memory safety).

• Sequence number monotonicity: global_sqnum set to max + 1 after scan.

• Volume headers always read from highest-revision reserved PEB.

• Reclaim error paths no longer leak PEBs.

[0.14.0] - 2026-03-30

Changed

• Reserved PEB module renamed with ubi_flash_res_peb_* prefix.

• Volume module deduplicated with shared helpers.

[0.13.0] - 2026-03-30

Added

• Bad block torture test with configurable cycles and per-PEB erase attempts.

• Runtime average erase counter tracking.

Fixed

• Use-after-free in leb_write() write-fail path.

• Bad-block paths now update erase counter averages.

[0.12.0] - 2026-03-30

Added

• Configurable write retry count for data PEBs.

Fixed

• Write failure in leb_write() now properly marks PEB as bad.

[0.11.0] - 2026-03-27

Added

• Initial crypto layer design proposal (AES-128-CCM via PSA Crypto API).

[0.10.0] - 2026-03-27

Added

• Reserved PEB management extracted into dedicated module.

• Configurable reserved PEB count (2-4) for cold spare support.

• 12 new tests (recovery, data_size boundary).

[0.9.0] - 2026-03-26

Changed

• Monolithic source restructured into core, volume, LEB, I/O, and cache modules.

• Init scan decomposed into 5 helpers.

• Overhauled Doxygen and Kconfig.

Fixed

• 11 bugs from code quality audit.

• Memory leak in duplicate-LEB resolution.

[0.8.0] - 2026-03-25

Added

• Sphinx documentation with Read the Docs theme, deployed to GitHub Pages.

• Doxygen + Breathe auto-generated API reference.

• Architecture guide, getting started, configuration reference, contributing guide.

[0.7.0] - 2026-03-25

Added

• native_sim board support.

• Test suites: error handling, boundary, recovery, stress — 87 tests total.

• GitHub Actions CI with build, test, and Codecov.

• Coverage infrastructure and CI scripts.

• Test strategy documentation.

Fixed

• west.yml: cmsis_6 renamed to cmsis for Zephyr v4.0.0.

[0.6.0] - 2026-03-24

Added

• Architecture guide with ASCII diagrams (on-flash layout, PEB lifecycle, init flow, wear-leveling).

• Development roadmap and contributor guide.

Fixed

• EBA table corruption during init when resolving sequence number conflicts.

[0.5.0] - 2025-09-25

Added

• Mutex-based synchronization for thread-safe operations.

[0.4.0] - 2025-09-24

Added

• Sample application for STM32U5.

Changed

• Optimized flash I/O and improved logging.

[0.3.0] - 2025-09-21

Added

• .clang-format configuration.

Changed

• Migrated from low-level flash APIs to Zephyr Flash Map (Flash Area API).

[0.2.0] - 2025-09-10

Added

• Volume support with static and dynamic types.

• Runtime resizing, write block alignment, partial dual-bank support.

• Hardware tests on STM32U5.

[0.1.0] - 2025-07-25

Added

• Initial release: device init/deinit, LEB I/O (map, unmap, read, write), PEB statistics.

• Hardware integration tests and sample application for STM32U5.

• Environment setup documentation.