The same scrub as the previous commit, over the files it did not reach:
the variant-MKB layout notes, the 2.1 segment index observations, the
PPS-revert regressions and the playlist-twin tiebreak.
Measurements keep their numbers — "a v70 `0x2d` body = 46_100*2 + 16"
is the useful part, and the title it came from never was.
The key map is now purely "these sectors use this key": entry_for returns
Option and an LBA in no range is left untouched (no default-decrypt-
everything fallback). resolve_mux_key_map builds explicit content ranges
for every case — single-CPS keys each content extent, multi-CPS keys each
extent with the key that opens it, and FMTS fills the non-segment content
with the base Unit Key so a whole-disc read decrypts content and passes
nav/filesystem through. Combined with the fail-loud resolve, a map can
never silently apply a wrong key, and clear sectors are never scrambled.
decrypt_sectors_mapped skips a unit with no map entry; read_plan keeps an
unmapped unit (pass-through content) and drops only alternate-phase
forensic units. Tests updated to the Option semantics.
mp4 demuxer (untrusted input): bound every allocation sized from a box
field (stsz/stco/stsc counts, stts/ctts run-lengths, per-sample and moov
sizes, plus an absolute cap so a sparse file can't inflate file_len);
guard the parse_stsd slice and a zero mdhd timescale; cap track count so
the per-track PID can't overflow; rewrite read_moov to handle size==0 /
size<8 / 64-bit largesize; parse esds/AudioSpecificConfig for AAC; write
tkhd duration in the movie timescale.
decrypt: resolve_mux_key_map now fails loud on an extent no key can
classify instead of inheriting the previous extent's key, so a keymap
never silently carries a wrong key; the sweep/patch key-fetch recovery
fails loud when a unit is still unresolved after the retry.
AACS: reject inverted forensic segments in both range builders; compare
the forensic index in u16 space so an out-of-range value can't truncate
onto a valid u8 index. RECOVERED_ERROR no longer latches the damage zone,
preserving the 30s wedge cooldown for a following hard error.
audio: AAC/MP2/MP3/FLAC carry the last PTS across a PES with no timestamp;
the DTS-HD extension-sync search is bounded to after the core; the MP4
16.16 sample-rate field saturates. demux_sink records the video reference
before the kind filter so audio:// / sub:// keep multi-clip PTS continuity
and the DELAY tag.
Remove a dead error variant and the AACS-unsupported-video code; codec
comments cite the primary format specs; assorted doc/naming fixes and
regression tests throughout.
FMTS (AACS 2.1) now decodes per (LBA, phase): Phase enum + AacsKeyMap::
from_ranges_phased, decrypt only the variant's parity half. resolve_fmts_key_map
does a 2-phase index-1 anchor then per-index phase probe, and sizes the forensic
set to whatever the source returns (no hardcoded 32). KeyFetch is now two explicit
operations (unit_keys / fmts_indexes) and KeySource splits get_uk into
get_unit_keys + get_fmts_indexes. BYPASS_FMTS_KEY gate removed (first-class format).
Teed up for 1.4.5. Local WIP baseline.
The keyserver protocol now returns all 32 index keys as an array for a
forensic content sample (and a single-element array for plain content).
resolve_fmts_key_map sends one forensic batch and maps array element i to
segment index i+1, replacing the per-index blind-probe collection loop
that repeatedly hit the key service. Segment/index parsing and the
aligned-unit content classification are reworked to support this:
- rename variant_select -> index_select (per-index, not per-variant)
- content classification moves to is_clean(buf, ContentFormat) so the
unit selector emits only units the key service accepts
- segment.rs: parse IndividualSegment.tbl index tags + SPN ranges,
build contiguous LBA key ranges from the resolved 32-key array
- decrypt/decorator plumbing for the resolved per-index keys
Fail loud (FmtsKeyMissing) when the forensic query returns < 32 keys or
any segment index stays unresolved.
Add UnitKey.variant_number (0 = ordinary, 1..32 = forensic variant) with new/variant constructors, and aacs::variant_select — resolve a disc's single variant and classify each aligned unit (default / variant / drop foreign / conceal keyless). Correct IndividualSegment.tbl: the per-record field is the variant (cycles 1..32 on a retail disc), not a segment number — Segment.number -> Segment.variant.
Replace the AACS-specific inline key-fetch in the decrypt decorator with
a scheme-neutral recovery seam: the input stream (L3) installs a Recover
closure (none / AACS key-fetch) and the decorator (L2) runs it at the
single decrypt-miss point. FMTS (AACS 2.1) forensic-segment units that no
key opens are just undecryptable units, concealed and counted as ordinary
decrypt loss with no FMTS-specific branch ("a loss is a loss"), so the
separate bytes_undecryptable bucket collapses into one loss count.
- sector/recovery.rs: the seam (MissOutcome, none/key_fetch factories),
naming no encryption scheme in its type.
- FMTS: segment routing primitives + BYPASS_FMTS_KEY, and an upfront
ensure_forensic_segments_decryptable gate (Error::FmtsKeyMissing) in
the mux input path, parallel to the unit-key gate.
- CSS descramble/rekey moves from decrypt_sectors into
css::descramble_region: CSS self-recovers from the data itself, so it
stays OFF the seam (which is only for external inputs).
- disc/mod.rs also: main-title selection aligned to largest physical
size; is_regular read from the open file handle, not metadata(path),
fixing a swallowed sync_all on a fresh-rip ISO. decrypt_threads()
resolved once via OnceLock off the per-buffer hot path.
New aacs::segment: parses the AACS 2.1 IndividualSegment.tbl into the source-packet ranges of the forensic variant segments (validated against a retail disc: 792 segments, 2560 packets each). First piece of the FMTS variant decoder — the segments' variants are encrypted under segment keys, not the unit key, so a unit-key rip corrupts them (broken HEVC refs).
Matthew Jackson