Post-read verify gate (new src/disc/verify.rs): UnitVerifier buffers/aligns the disc-absolute read stream into clip-file 6144-byte units, then makes one decryptability() decision per unit (CPI gate -> held keys -> key_fetch -> strict TS). POST_READ_VERIFY const kill-switch; fail-safe contract (only ever downgrades units it is confident are undecryptable; every doubt skips). Hooked into Disc::sweep (producer observes ciphertext -> WorkItem::MarkBad after the Good, FIFO-ordered) and Disc::patch (post-loop reverify_iso reads recovered units whole from the patched ISO). extract::clip_layouts enumerates AACS clips for the gate.
Standards-correct AACS verify: aacs::unit_is_clean_ts is a strict port of libaacs _verify_ts (all 32 TS syncs, not a majority vote); decrypt_unit accepts a key only on it; the majority verify_ts is removed. Deleted the Disc::verify_clips post-pass bolt-on (its primitive is absorbed by the read-path gate).
libaacs/DVD audit fixes: content-cert bus_encryption flag now read from bit 7 (was bit 0 - defeated the bus-key fail-loud gate); cc_id read from offset 14; title_cps_unit range-validated + 1->0 index-converted per libaacs. Corrected attack_crib ("functionally-equivalent" not "exact" port) and read_disc_key (READ DVD STRUCTURE 0xAD, not REPORT KEY) doc comments.
Also includes accumulated uncommitted work: key-fetch seam and TrueHD/DTS audio fix.
Surgical fixes (each with a regression test that fails without the change):
mux/mkv.rs, mux/demux_sink.rs: drive the clip-boundary timeline epoch
off the resolved PRIMARY VIDEO track, not the literal stream index 0.
An M2TS/PMT title can list an audio ES before video, so streams[0] may
be audio; a non-video epoch driver ratchets the frontier and inflates
the timeline. mkv cluster-opening falls back to track 0 for audio-only
titles so they still open clusters.
mux/codec/ac3.rs: correct ACMOD_CHANNELS — acmod=5 (3/1) is 4 channels,
not 3 (was undercounting a 3/1 stream); fix the A/52 Table 5.8 doc.
disc/mod.rs: HDMV coding_type 0x91 (Interactive Graphics / menus) no
longer maps to PGS subtitle — it falls through to Unknown so the PMT/STN
walker drops it instead of surfacing a bogus subtitle track.
mux/videomap.rs + mux/mkv.rs: FVI colour now mirrors the MKV muxer's CICP
precedence (measured CICP authoritative; HDR-driven PQ/HLG transfer
override) via a shared cicp_for_video helper, so the two sinks can't
disagree (HDR10 BT.2020 no longer emits SDR transfer 14).
mux/mkvstream.rs: saturating_add on cluster_ts + rel_ts so an adversarial
CLUSTER_TIMESTAMP near i64::MAX can't overflow/panic before the existing
saturating_mul.
mux/timeline.rs: tighten the tail-straggler clamp so a normal new-epoch
non-video frame leading the sparse video frontier by >3s is not demoted
into the previous clip's epoch.
mux/m2ts_mux/mod.rs: re-stamp PCR per video TS packet (mid-PES), not only
at PES boundaries, so a large UHD I-frame can't open a multi-second PCR
gap; modular 33-bit PTS rebasing so a real 90 kHz clock wrap is not
collapsed to PTS 0 (pre-base frames still floor to 0).
io/byte_prefetcher.rs, sector/prefetched.rs: wrap the producer feed loop
in catch_unwind and emit a typed error sentinel on panic, so a mid-stream
producer panic is not read as a clean EOF at the demux boundary (which
would silently truncate the mux).
mux/codec/h264.rs: extend HIGH_PROFILES to the full ISO/IEC 14496-15 set
that mandates the avcC chroma/bit-depth extension (adds 244 et al.).
Doc/comment accuracy: css/mod.rs (50000 sectors, not scrambled-sectors),
aacs/decrypt.rs (decrypt_unit already-clear path), ifo.rs (TT_SRPT at
0xC4), css/lfsr.rs (LFSR0 24-bit; TAB1-then-XOR cipher; real scramble-flag
predicate), disc/read_error.rs (for_sweep does bounded transient retries).
Skipped: keydb.rs SSRF guard (low/latent, no live caller) — a hard
loopback block breaks an existing behavioral test that exercises the
header-EOF path over a loopback server; a clean fix needs a resolver test
seam beyond this surgical pass. The sibling keydb_fetch.rs comment fix is
out of scope (freemkv crate).
mux/mkv: assert emitted CODEC_PRIVATE bytes verbatim for H.264/HEVC/VC-1/
MPEG-2 (direct TrackEntry child, not nested in Video) and DefaultDuration ns
for all eight frame rates, read back out of a real MkvMuxer.
disc/sweep: end-to-end Disc::sweep against a synthetic MockReader with an
injected bad region, asserting the resulting mapfile marks the clean lead
Finished and the failed batch + zero-filled skip-ahead gap NonTrimmed,
proving the Pass-1 damage-jump engaged.
disc/patch: introduce a minimal clock seam (fn() -> Instant on the internal
PatchLoopState, defaulting to Instant::now) so the per-range and whole-pass
watchdogs are deterministically testable; public API and callers unchanged,
production behavior identical. Add tests that advance a fake clock to trip the
range budget and whole-pass stall predicate.
aacs: add an AES-128-CBC known-answer test for aes_cbc_decrypt using the
published NIST SP 800-38A F.2.2 vector (blocks 1..3 exact; block 0 via the
documented fixed-AACS-IV substitution).
1. HEVC CRA->BLA false-trigger on 33-bit PTS wraparound
(src/mux/codec/hevc.rs): the clip-boundary auto-detect compared the
RAW 33-bit PES PTS against the high-water mark, so a single-clip title
crossing 2^33->0 (~26.5h) false-armed pending_clip_boundary and rewrote
a legitimate in-clip CRA(21)->BLA_W_LP(16), dropping valid RASL pictures
(visible corruption) and breaking the single-clip byte-identical
guarantee. Now unwrap the PTS onto a monotonic 64-bit timeline first
(a near-full-period backstep is a wrap: add 2^33, update the watermark,
do not arm). Regression test cra_after_33bit_pts_wrap_not_rewritten;
the genuine-clip-join test still passes.
2. Single-pass recovery read bypassed the transport-failure abort
(src/mux/disc.rs): the line-442 short-circuit only inspected the 10s
read res. A transport failure (status 0xFF, wedged USB bridge) on the
60s recovery read fell into the skip_errors branch and zero-filled/
advanced, marching the disc at one bridge-recovery per probe
(run-forever, hard rule #2). Re-check the recovery error for
is_scsi_transport_failure() before the skip block and abort with
Error::DiscRead. Test transport_failure_on_recovery_read_aborts_even_with_skip_errors.
3. Recovery-read SUCCESS branch had no coverage (src/mux/disc.rs tests):
added RecoverableReader (errors when recovery=false, succeeds when
recovery=true) and test recovery_read_success_muxes_recovered_data_no_skip
driving fill_extents to the size-1 bottom-out and asserting the recovered
data is muxed (counters advance, no skip).
4. TrueHD channel-correction probe omitted set_unit_base
(src/disc/mod.rs correct_truehd_channels): the probe read via a
DecryptingSectorSource without anchoring the AACS unit-alignment gate,
so it degraded to absolute start_lba % 3 and returned DecryptFailed on a
non-3-aligned extent, silently understating Atmos/7.1 as 5.1. Now call
set_unit_base(ext.start_lba) before the probe read (no-op for CSS/None).
5. is_unit_aligned lba<unit_base latent trap (src/aacs/decrypt.rs):
wrapping_sub mis-gated when lba < unit_base (2^32 == 1 mod 3). Switched
to saturating_sub (clamps offset to 0, a unit boundary) and pinned the
contract with is_unit_aligned_lba_below_base_is_well_defined plus
is_unit_aligned_relative_to_base.
cargo +1.86 fmt --check / clippy -D warnings / test --tests all green.
The AACS unit-alignment gate measured `lba % 3` against absolute disc LBA 0,
but aligned units are anchored at each clip's encrypted-region start. A clip
whose start_lba is not 3-aligned had its readable units wrongly rejected with
"Decryption failed" (the big-title-only failure on some Blu-rays). One
canonical clip-anchored helper (`aacs::is_unit_aligned`) is now the single
source of truth for the decrypt-on-read gate; both mux read paths set the
per-extent `unit_base = start_lba` via a new `SectorSource::set_unit_base`.
Also moves key *mechanism* into the library: the encrypted sample reader
(`read_encrypted_units`) and the candidate-key resolution loop
(`resolve_and_apply`) now live here, so a key source is purely a lookup.
Regression test covers a clip based at a non-3-aligned LBA.
Test-hardening release, no runtime changes. Adds spec-grounded unit tests
across the silent-corruption surfaces — UDF/MPLS/CLPI/IFO parsing, BD/DVD
title + extent assembly, AACS/CSS key handling, TS/PS demux + codec parsers,
MKV/EBML container output, the mux pipeline, sector prefetch + decrypt
decorator, drive/SCSI sense decoding, label extraction, and core I/O. Each
test is grounded in the format spec or real on-disc behavior and verified to
fail under a targeted source mutation. No behavior changed.
Library-wide review-and-fix pass: tightened AACS keydb/handshake/variant
handling and trailing-partial-unit policy, corrected MPLS mark offset and
added UDF allocation bounds, hardened the mux/codec framing and M2TS paths,
guarded SCSI READ CAPACITY short transfers and unified error mapping, added
overflow guards on untrusted disc input, and made prefetch shutdown
deterministic. Release profile now builds with thin LTO + single codegen unit.
Fight Club redefines PPS id 0 mid-title; the parser froze the first PPS into
codecPrivate and stripped the rest, so the redefined segment decoded against
the wrong PPS (CABAC/cu_qp_delta desync, intact framing). Now any VPS/SPS/PPS
whose body differs from the codecPrivate copy is emitted in-band at every
occurrence, overriding the hvcC copy a player re-applies per keyframe. Proven:
Fight Club re-mux decode errors 320+ -> 0 across all corrupt regions.
Also adds aacs::unit_key_validates (1-block early-reject UK validation) and
ts_sync_count/ts_packet_total helpers.
Audit-driven fixes (rounds 1–3):
- hevc: correct hvcC profile/level SPS offsets (HEVC has a 2-byte NAL header)
- mkv: map all DTS variants to the registered A_DTS codec id; force a new
cluster before the i16 cluster-relative timestamp can overflow
- ebml/mkvstream: bound untrusted EBML sizes (no multi-GB allocs); reject
uint>8 (was an OOB panic) and non-{0,4,8} float widths (were a desync)
- ts: skip PES-header bytes that span a TS packet boundary; add the PMT
section_len/prog_info_len bounds the PAT parser already had
- ac3: preserve a 0x0B77 syncword split across a PES boundary; cap buffer
- dts: validate each next-core boundary by decoded core size (a 0x7FFE8001
pattern inside XLL payload no longer false-splits/drops the lossless
extension); reject sub-minimum core frames; fix forced-emit PTS base
- lpcm: DVD program-stream PCM no longer double-strips the BD LPCM header
- vc1/mpeg2: do not emit a parameter-set-only PES as a standalone frame
- pgs/truehd: cap the pending reassembly buffer (parity with ac3/dts)
- aacs: ts_syncs_intact uses the exact packet count
- prefetched: capacity-guard the recycled-buffer set_len
- Cargo.toml: exclude project docs from the published crate
Convergence: a third independent audit pass found no remaining material
(CRITICAL/HIGH/MEDIUM) issues. Full precommit (fmt + clippy -D + tests,
Rust 1.86) green.
Rename is_unit_encrypted -> is_aacs_scrambled and decide encryption from the unit's MPEG-TS sync bytes (destroyed by the encrypted body) instead of the TP_extra copy-control (byte 0) or TS scrambling-control (byte 7) flags, which discs do not set reliably. One shared predicate now backs the decrypt gate and out-of-band key validation, so callers agree on what 'encrypted' means. Decryption restores the syncs, so a decrypted unit reads as clear and there is no flag to clear.
is_unit_encrypted read the TP_extra copy-control bits (byte 0), which are a
copy-permission flag, not an encryption flag. On discs whose sampled units are
clear navigation packets (PAT/PMT) those bits can be set while the unit is not
scrambled, so a correct Unit Key was used to 'decrypt' already-plaintext data,
produced garbage, and the key was wrongly treated as failing.
Read the actual flag instead: the TS transport_scrambling_control bits (top two
of TS-header byte 3 = byte 7 of the aligned unit, inside the clear seed). AACS
encrypts whole aligned units, so this one packet's TSC reflects the unit.
decrypt_unit now clears the TSC bits of every packet on the way out so the
result is valid unscrambled TS. Tests updated to the TSC flag.
Matthew Jackson