Matthew Jackson
a7bd574c34
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.
1160 lines
49 KiB
Rust
1160 lines
49 KiB
Rust
//! AACS content decryption — AES primitives, unit decryption, bus encryption.
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use aes::Aes128;
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use aes::cipher::{BlockDecrypt, BlockEncrypt, KeyInit, generic_array::GenericArray};
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// ── AACS constants ──────────────────────────────────────────────────────────
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/// Fixed IV used by AACS for all AES-CBC operations.
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pub(crate) const AACS_IV: [u8; 16] = [
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0x0B, 0xA0, 0xF8, 0xDD, 0xFE, 0xA6, 0x1F, 0xB3, 0xD8, 0xDF, 0x9F, 0x56, 0x6A, 0x05, 0x0F, 0x78,
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];
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/// Size of an AACS aligned unit (3 × 2048-byte sectors).
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pub const ALIGNED_UNIT_LEN: usize = 6144;
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/// An AACS aligned unit spans this many 2048-byte sectors (3).
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pub const ALIGNED_UNIT_SECTORS: u32 = (ALIGNED_UNIT_LEN / SECTOR_BYTES) as u32;
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/// Whether `lba` sits on an AACS aligned-unit boundary, measured **relative to
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/// the encrypted region's base LBA** (`unit_base` = the clip/extent `start_lba`,
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/// NOT absolute disc LBA 0).
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///
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/// AACS aligned units (6144 B / 3 sectors) are anchored at the start of each
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/// clip's encrypted region, so a read must begin a whole number of units past
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/// that base for `decrypt_sectors` (which anchors units at buffer offset 0) to
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/// align the CBC correctly. This is the SINGLE source of truth for the test —
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/// the decrypt-on-read gate, the inline and highway mux read paths, and the
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/// key-validation sample reader all key off this, never absolute `lba % 3`. A
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/// disc whose clip `start_lba` is not itself 3-aligned would otherwise mis-gate
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/// (reject readable units, then report "Decryption failed") on exactly the
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/// titles whose clips land off a 3-boundary.
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///
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/// `lba` is always `>= unit_base` by contract (a read never begins before the
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/// extent base it is measured against). `saturating_sub` makes the `lba <
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/// unit_base` case well-defined anyway — it clamps the offset to 0, which is a
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/// unit boundary — rather than the latent `wrapping_sub` trap where an
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/// underflow wraps to ~2^32 and, because `2^32 ≡ 1 (mod 3)`, mis-reports the
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/// alignment (e.g. `lba == unit_base - 1` would falsely read as aligned).
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pub fn is_unit_aligned(lba: u32, unit_base: u32) -> bool {
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lba.saturating_sub(unit_base) % ALIGNED_UNIT_SECTORS == 0
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}
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use crate::consts::SECTOR_BYTES;
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use crate::consts::BD_SOURCE_PACKET_BYTES;
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/// TS sync byte.
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const TS_SYNC: u8 = 0x47;
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// ── AES primitives ──────────────────────────────────────────────────────────
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/// AES-128-ECB encrypt a single 16-byte block.
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pub(crate) fn aes_ecb_encrypt(key: &[u8; 16], data: &[u8; 16]) -> [u8; 16] {
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let cipher = Aes128::new(GenericArray::from_slice(key));
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let mut block = GenericArray::clone_from_slice(data);
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cipher.encrypt_block(&mut block);
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let mut out = [0u8; 16];
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out.copy_from_slice(&block);
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out
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}
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/// AES-128-ECB decrypt a single 16-byte block.
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pub(crate) fn aes_ecb_decrypt(key: &[u8; 16], data: &[u8; 16]) -> [u8; 16] {
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let cipher = Aes128::new(GenericArray::from_slice(key));
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let mut block = GenericArray::clone_from_slice(data);
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cipher.decrypt_block(&mut block);
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let mut out = [0u8; 16];
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out.copy_from_slice(&block);
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out
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}
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/// AES-128-CBC decrypt in-place with the fixed AACS IV.
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///
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/// Precondition: `data.len()` is a multiple of 16. Any trailing partial
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/// block is silently ignored; all callers pass aligned regions (6128 and
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/// 2032 bytes), and the assert documents/enforces that contract.
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pub(crate) fn aes_cbc_decrypt(key: &[u8; 16], data: &mut [u8]) {
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debug_assert!(
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data.len() % 16 == 0,
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"aes_cbc_decrypt requires a block-aligned slice"
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);
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let cipher = Aes128::new(GenericArray::from_slice(key));
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let num_blocks = data.len() / 16;
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// Process blocks in reverse to avoid clobbering ciphertext needed for XOR
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for i in (0..num_blocks).rev() {
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let offset = i * 16;
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let prev = if i == 0 {
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AACS_IV
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} else {
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let mut p = [0u8; 16];
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p.copy_from_slice(&data[(i - 1) * 16..i * 16]);
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p
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};
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let mut block = GenericArray::clone_from_slice(&data[offset..offset + 16]);
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cipher.decrypt_block(&mut block);
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for j in 0..16 {
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data[offset + j] = block[j] ^ prev[j];
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}
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}
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}
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// ── Content decryption ──────────────────────────────────────────────────────
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/// True if a 6144-byte aligned unit's MPEG-TS sync structure is DESTROYED — it
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/// lacks the `0x47` sync bytes a clear BD-TS unit carries at offsets 4, 196,
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/// 388, … (one per 192-byte source packet).
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///
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/// This is a pure BYTE heuristic; on its own it does NOT mean "encrypted". A
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/// destroyed sync structure can be AACS ciphertext, uncorrected-ECC garbage, OR
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/// data that was never MPEG-TS at all (UDF filesystem / nav) — those are
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/// byte-indistinguishable. So this answers only *"does this unit look like valid
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/// clear TS, or not"*, nothing about encryption.
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///
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/// The "is this unit AACS-encrypted (and must decrypt)?" decision is COMPOSED by
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/// the caller, because it needs context this function lacks:
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/// `inside an m2ts content extent` AND `ts_sync_destroyed` AND `no key decrypts`
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/// (see [`crate::decrypt::decrypt_sectors_in_content`] and
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/// [`crate::Disc::encrypted_content_ranges`]). Inside known content this
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/// primitive separates an encrypted/garbled unit (destroyed) from a clear
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/// segment (intact); OUTSIDE content it is meaningless — feeding it filesystem
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/// bytes is what produced the first-2 GB false-positive this split fixes.
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///
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/// Flag-independent: it does NOT read the TP_extra copy-control bits (byte 0) or
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/// the TS scrambling-control bits (byte 7) — AACS sets neither reliably.
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pub fn ts_sync_destroyed(unit: &[u8]) -> bool {
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unit.len() >= ALIGNED_UNIT_LEN && !ts_syncs_intact(unit)
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}
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/// The AUTHORITATIVE AACS "is this aligned unit encrypted?" signal — the Copy
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/// Permission Indicator (CPI) in the top 2 bits of byte 0. Byte 0 is the first
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/// byte of the first source packet's `TP_extra_header`, which AACS always leaves
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/// in the clear (the first 16 bytes of every unit are the unencrypted SEED). So
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/// this is readable WITHOUT a key:
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/// * `(buf[0] & 0xC0) == 0` → CPI clear → the unit is plaintext; pass through.
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/// * non-zero → bytes `16..6144` are AES-CBC encrypted; decrypt.
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///
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/// This is exactly libaacs' test (`if (!(buf[0] & 0xc0)) return; /* clear */`)
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/// and is the spec-correct replacement for the [`ts_sync_destroyed`] byte
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/// heuristic. CRITICAL: it is only meaningful when `unit` is read at the correct
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/// clip-FILE-anchored boundary — byte 0 must be the real unit start. A
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/// disc-absolute / mis-aligned read makes byte 0 arbitrary mid-stream data, so
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/// the CPI bits are meaningless (which is precisely why per-unit verify must run
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/// clip-anchored, not in the whole-disc sweep).
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pub fn aacs_unit_encrypted(unit: &[u8]) -> bool {
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unit.len() >= ALIGNED_UNIT_LEN && (unit[0] & 0xC0) != 0
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}
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/// True when an aligned unit is flagged encrypted (CPI set) AND still looks
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/// scrambled (TS syncs not yet restored) — i.e. genuine encrypted content that
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/// has NOT been decrypted yet.
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///
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/// [`aacs_unit_encrypted`] is the authoritative spec gate, but the CPI bits live
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/// in the plaintext header (bytes `0..16`) which decryption never rewrites, so a
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/// successfully decrypted unit still reports CPI-set. Buffer-iterating sites that
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/// may run twice over the same `buf` (the post-fetch re-decrypt, sample
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/// collection, failure diagnosis) need an IDEMPOTENT "does this still need work?"
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/// test, so they compose CPI with the sync-restored check: once a unit decrypts,
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/// its syncs come back and it drops out. Single-shot callers that always operate
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/// on fresh ciphertext (`decrypt_unit`) gate on [`aacs_unit_encrypted`] alone.
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///
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/// Like CPI itself this is only meaningful at the clip-FILE-anchored boundary.
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pub fn aacs_unit_needs_decrypt(unit: &[u8]) -> bool {
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aacs_unit_encrypted(unit) && ts_sync_destroyed(unit)
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}
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/// Count the MPEG-TS sync bytes (`0x47`) present at the BD-TS packet stride
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/// (offset 4 and every 192 bytes after — 4-byte TP_extra_header + 188-byte
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/// TS packet). A clear or correctly-decrypted m2ts unit shows ~one per
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/// packet; an encrypted unit, or a non-content unit decrypted under a key
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/// that doesn't apply, shows ~none.
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pub fn ts_sync_count(unit: &[u8]) -> usize {
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let mut count = 0;
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let mut offset = 4;
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while offset < unit.len() {
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if unit[offset] == TS_SYNC {
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count += 1;
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}
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offset += BD_SOURCE_PACKET_BYTES;
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}
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count
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}
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/// Number of BD-TS packets in the unit — the maximum possible sync count.
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pub fn ts_packet_total(unit: &[u8]) -> usize {
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// One sync byte per 192-byte BD-TS packet (at offset 4 of each). The old
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// `(len - 4) / BD_SOURCE_PACKET_BYTES + 1` over-counted by one for lengths of the
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// form `4 + k·192`.
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unit.len() / BD_SOURCE_PACKET_BYTES
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}
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fn ts_syncs_intact(unit: &[u8]) -> bool {
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ts_sync_count(unit) > ts_packet_total(unit) / 2
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}
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/// STRICT, standards-correct "is this a clean MPEG-TS aligned unit?" check —
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/// byte-for-byte libaacs' `_verify_ts` (`aacs.c`): EVERY one of the 32 BD source
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/// packets (192-byte stride) must carry its TS sync `0x47` at offset 4; the first
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/// miss fails. This is the authoritative gate for the POST-READ verify stage,
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/// independent of (and not coupled to) `decrypt_unit`.
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///
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/// It is deliberately stricter than the majority-vote `ts_syncs_intact`
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/// scramble *heuristic*: a wrong-key decrypt that coincidentally restores >16
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/// syncs passes the majority test and would silently corrupt content, but fails
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/// here. Non-mutating — purely a verdict; it neither decrypts nor clears the CPI
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/// bits (those stay the concern of the unchanged `decrypt_unit`).
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pub fn unit_is_clean_ts(unit: &[u8]) -> bool {
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if unit.len() < ALIGNED_UNIT_LEN {
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return false;
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}
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let mut i = 0;
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while i < ALIGNED_UNIT_LEN {
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if unit[i + 4] != TS_SYNC {
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return false;
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}
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i += BD_SOURCE_PACKET_BYTES;
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}
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true
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}
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/// Decrypt one AACS aligned unit (6144 bytes) in-place.
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/// Returns true if the unit is now clear MPEG-TS: either it was already
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/// unscrambled (returned untouched, no key used) or it was decrypted and
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/// verified by its TS sync bytes. Returns false only when the unit was
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/// scrambled and this key failed verification.
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///
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/// Algorithm:
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/// 1. AES-128-ECB encrypt first 16 bytes with unit_key → derived
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/// 2. XOR derived with original 16 bytes → unit_decrypt_key
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/// 3. AES-128-CBC decrypt bytes 16..6143 with unit_decrypt_key and AACS IV
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///
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/// Decryption restores the TS sync bytes, so the unit reads as clear afterward;
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/// there is no flag to clear.
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pub fn decrypt_unit(unit: &mut [u8], unit_key: &[u8; 16]) -> bool {
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if unit.len() < ALIGNED_UNIT_LEN {
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return false;
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}
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if !aacs_unit_encrypted(unit) {
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return true; // CPI flag clear → plaintext, pass through untouched
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}
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// Save original first 16 bytes (they're plaintext TP_extra_header)
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let mut header = [0u8; 16];
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header.copy_from_slice(&unit[..16]);
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// Step 1: Encrypt header with unit key to derive per-unit key
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let derived = aes_ecb_encrypt(unit_key, &header);
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// Step 2: XOR to get the actual decryption key
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let mut decrypt_key = [0u8; 16];
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for i in 0..16 {
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decrypt_key[i] = derived[i] ^ header[i];
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}
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// Step 3: Decrypt bytes 16..6143 with AES-CBC
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aes_cbc_decrypt(&decrypt_key, &mut unit[16..ALIGNED_UNIT_LEN]);
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// Decryption restored the TS syncs; accept the key only if the unit is now
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// STRICTLY clean MPEG-TS (all 32 syncs) — the standards-correct gate, shared
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// with the post-read verify stage. A wrong key that coincidentally restores
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// a majority of syncs is rejected here, not silently accepted.
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unit_is_clean_ts(unit)
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}
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/// Fast, NON-MUTATING unit-key validation for the brute-force key search.
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///
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/// `decrypt_unit` pays a full 6128-byte (383-block) CBC decrypt before
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/// `verify_ts` can reject a wrong key — but in a brute scan ~every candidate is
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/// wrong. In CBC the plaintext of block *i* is `AES_dec(C_i) XOR C_{i-1}`, so
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/// the FIRST restored TS sync byte (payload offset 196, which lands in CBC
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/// block 11 of the `unit[16..]` region) can be recovered with a SINGLE block
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/// decrypt instead of 383. A wrong key fails this 1-byte gate ~255/256 of the
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/// time for the cost of one AES block; the rare survivor is then confirmed with
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/// the full [`decrypt_unit`], so the set of accepted keys is bit-for-bit
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/// identical to the slow path.
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///
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/// The caller MUST pass an aligned, already-[`ts_sync_destroyed`] unit
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/// (`unit.len() >= ALIGNED_UNIT_LEN`). The brute pre-filters its units, so the
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/// per-candidate scramble re-scan is intentionally skipped here.
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///
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/// NOTE: this is a search accelerator — it never writes the input and never
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/// participates in the content decrypt path. Aggregate correctness (does a key
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/// validate against *any* of the disc's units) is preserved because a true key
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/// restores offset-196 on every standard BD-TS unit.
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pub fn unit_key_validates(unit: &[u8], unit_key: &[u8; 16]) -> bool {
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if unit.len() < ALIGNED_UNIT_LEN {
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return false;
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}
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// Per-unit decrypt key: AES-ECB-encrypt the 16-byte plaintext header with
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// the unit key, XOR with the header (same derivation as `decrypt_unit`).
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let mut header = [0u8; 16];
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header.copy_from_slice(&unit[..16]);
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let derived = aes_ecb_encrypt(unit_key, &header);
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let mut decrypt_key = [0u8; 16];
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for i in 0..16 {
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decrypt_key[i] = derived[i] ^ header[i];
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}
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// Cheap gate: recover ONLY payload byte 196 (the 2nd BD-TS packet's sync).
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// The CBC region is `unit[16..]`; payload offset 196 → region offset 180 =
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// block 11, byte 4. P[11] = AES_dec(C[11]) XOR C[10]; C[10] is raw
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// ciphertext (no decrypt needed). Constant offsets for the fixed 6144 unit.
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const SYNC_PAYLOAD_OFF: usize = 196;
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let region_off = SYNC_PAYLOAD_OFF - 16; // 180
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let blk = region_off / 16; // 11
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let byte = region_off % 16; // 4
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let c11 = 16 + blk * 16; // absolute offset of C[11] in `unit` (=192)
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let cipher = Aes128::new(GenericArray::from_slice(&decrypt_key));
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let mut b = GenericArray::clone_from_slice(&unit[c11..c11 + 16]);
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cipher.decrypt_block(&mut b);
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let prev = unit[c11 - 16 + byte]; // C[10] byte (region block 10)
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if b[byte] ^ prev != TS_SYNC {
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return false;
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}
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// Survivor (~1/256 of candidates): confirm with the authoritative full
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// decrypt + verify, so the verdict matches `decrypt_unit` exactly.
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let mut full = [0u8; ALIGNED_UNIT_LEN];
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full.copy_from_slice(&unit[..ALIGNED_UNIT_LEN]);
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decrypt_unit(&mut full, unit_key)
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}
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/// Outcome of [`decrypt_unit_try_keys`].
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///
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/// Distinguishes "the unit was already clear, no key was consumed" from "key
|
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/// at index `i` decrypted it" — the bare `Option<usize>` form conflated the two
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/// (a clear unit reported `Some(0)`, indistinguishable from key index 0, and
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/// possibly out of range when `unit_keys` is empty).
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub enum UnitKeyResult {
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/// The unit was not scrambled; it was left untouched and no key was used.
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AlreadyClear,
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/// The unit was decrypted in place by `unit_keys[index]`.
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DecryptedWith(usize),
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}
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/// Decrypt one aligned unit trying multiple unit keys.
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///
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/// Returns [`UnitKeyResult::AlreadyClear`] if the unit was not scrambled (no key
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/// consumed), [`UnitKeyResult::DecryptedWith(i)`] if key `i` decrypted it, or
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/// `None` if no key worked (the unit is restored to its original bytes).
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pub fn decrypt_unit_try_keys(unit: &mut [u8], unit_keys: &[[u8; 16]]) -> Option<UnitKeyResult> {
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if !aacs_unit_encrypted(unit) {
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return Some(UnitKeyResult::AlreadyClear);
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}
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|
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// Save original for retry. Stack-backed buffer — no heap allocation, and the
|
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// restore-on-failure contract holds uniformly regardless of key count.
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let mut original = [0u8; ALIGNED_UNIT_LEN];
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original.copy_from_slice(&unit[..ALIGNED_UNIT_LEN]);
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|
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for (i, key) in unit_keys.iter().enumerate() {
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unit[..ALIGNED_UNIT_LEN].copy_from_slice(&original);
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if decrypt_unit(unit, key) {
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return Some(UnitKeyResult::DecryptedWith(i));
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}
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}
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// Restore original on failure
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unit[..ALIGNED_UNIT_LEN].copy_from_slice(&original);
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None
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}
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/// Remove bus encryption from an aligned unit (AACS 2.0 / UHD).
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/// Bus encryption uses read_data_key, decrypting bytes 16..2047 of each 2048-byte sector.
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pub fn decrypt_bus(unit: &mut [u8], read_data_key: &[u8; 16]) {
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for sector_start in (0..ALIGNED_UNIT_LEN).step_by(SECTOR_BYTES) {
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if sector_start + SECTOR_BYTES > unit.len() {
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break;
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}
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// First 16 bytes of each sector are plaintext
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aes_cbc_decrypt(
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read_data_key,
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&mut unit[sector_start + 16..sector_start + SECTOR_BYTES],
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||
);
|
||
}
|
||
}
|
||
|
||
/// Full decrypt of an aligned unit: bus decrypt (if needed) then AACS decrypt.
|
||
pub fn decrypt_unit_full(
|
||
unit: &mut [u8],
|
||
unit_key: &[u8; 16],
|
||
read_data_key: Option<&[u8; 16]>,
|
||
) -> bool {
|
||
if !ts_sync_destroyed(unit) {
|
||
return true;
|
||
}
|
||
if let Some(rdk) = read_data_key {
|
||
decrypt_bus(unit, rdk);
|
||
}
|
||
decrypt_unit(unit, unit_key)
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
|
||
#[test]
|
||
fn test_aes_ecb_roundtrip() {
|
||
let key = [
|
||
0x15u8, 0x66, 0x5F, 0x98, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A,
|
||
0x0B, 0x0C,
|
||
];
|
||
let plain = [0x41u8; 16];
|
||
let enc = aes_ecb_encrypt(&key, &plain);
|
||
let dec = aes_ecb_decrypt(&key, &enc);
|
||
assert_eq!(dec, plain);
|
||
}
|
||
|
||
#[test]
|
||
fn is_unit_aligned_relative_to_base() {
|
||
// Aligned at the base and every 3 sectors above it; misaligned between.
|
||
assert!(is_unit_aligned(100, 100), "base itself is aligned");
|
||
assert!(is_unit_aligned(103, 100), "one unit past base is aligned");
|
||
assert!(is_unit_aligned(106, 100));
|
||
assert!(!is_unit_aligned(101, 100));
|
||
assert!(!is_unit_aligned(102, 100));
|
||
// Non-3-aligned base: alignment is RELATIVE to the base, not absolute.
|
||
assert!(is_unit_aligned(101, 101), "non-3-aligned base is aligned");
|
||
assert!(is_unit_aligned(104, 101));
|
||
assert!(!is_unit_aligned(102, 101));
|
||
}
|
||
|
||
#[test]
|
||
fn is_unit_aligned_lba_below_base_is_well_defined() {
|
||
// Latent-trap contract (rc.5.2 audit #5): a read never starts before its
|
||
// extent base, but if `lba < unit_base` the result must be well-defined,
|
||
// NOT the `wrapping_sub` underflow that — because 2^32 ≡ 1 (mod 3) —
|
||
// would falsely report alignment. `saturating_sub` clamps to offset 0,
|
||
// which is a unit boundary, so any `lba <= unit_base` reads as aligned.
|
||
assert!(
|
||
is_unit_aligned(99, 100),
|
||
"lba just below base must not wrap"
|
||
);
|
||
assert!(is_unit_aligned(98, 100));
|
||
assert!(is_unit_aligned(0, 100));
|
||
// The specific wrapping_sub trap value: unit_base - 1. With wrapping_sub
|
||
// this is 0xFFFF_FFFF % 3 == 0 → falsely "aligned" by underflow; with
|
||
// saturating_sub it is genuinely 0 → aligned, for the right reason.
|
||
assert!(is_unit_aligned(u32::MAX, u32::MAX)); // base == lba, trivially aligned
|
||
assert!(
|
||
is_unit_aligned(0, u32::MAX),
|
||
"max base, lba 0 must saturate to 0"
|
||
);
|
||
}
|
||
|
||
#[test]
|
||
fn test_decrypt_unit_unencrypted() {
|
||
// A clear unit (TS syncs intact) is not scrambled → passes through.
|
||
let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
|
||
let mut off = 4;
|
||
while off < ALIGNED_UNIT_LEN {
|
||
unit[off] = TS_SYNC;
|
||
off += BD_SOURCE_PACKET_BYTES;
|
||
}
|
||
let key = [0u8; 16];
|
||
assert!(!ts_sync_destroyed(&unit));
|
||
assert!(decrypt_unit(&mut unit, &key));
|
||
}
|
||
|
||
#[test]
|
||
fn ts_packet_total_no_off_by_one() {
|
||
// The maximum sync count is exactly the number of stride
|
||
// positions the counting loop visits (offset 4, 196, ...), i.e.
|
||
// len / 192, NOT (len - 4) / 192 + 1. For the 6144-byte aligned unit
|
||
// the loop checks offsets 4..=5956 → 32 positions.
|
||
let unit = vec![0u8; ALIGNED_UNIT_LEN];
|
||
assert_eq!(ts_packet_total(&unit), 32);
|
||
// Confirm the loop visits exactly that many stride positions.
|
||
let visited = (4..ALIGNED_UNIT_LEN)
|
||
.step_by(BD_SOURCE_PACKET_BYTES)
|
||
.count();
|
||
assert_eq!(visited, ts_packet_total(&unit));
|
||
}
|
||
|
||
#[test]
|
||
fn scramble_detection_at_16_32_boundary() {
|
||
// With 32 stride positions the majority threshold is
|
||
// total/2 = 16. A unit with EXACTLY half its syncs intact (16) must
|
||
// NOT be over-counted into the "scrambled" bucket by an inflated
|
||
// total: 16 > 16 is false → not-intact → scrambled. 17 intact → clear.
|
||
// The fix is that `total` is 32 (not 33), so the boundary sits cleanly
|
||
// at the real midpoint.
|
||
let set_syncs = |n: usize| {
|
||
let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
|
||
let mut off = 4;
|
||
let mut placed = 0;
|
||
while off < ALIGNED_UNIT_LEN && placed < n {
|
||
unit[off] = TS_SYNC;
|
||
off += BD_SOURCE_PACKET_BYTES;
|
||
placed += 1;
|
||
}
|
||
unit
|
||
};
|
||
|
||
assert_eq!(ts_sync_count(&set_syncs(16)), 16);
|
||
assert_eq!(ts_sync_count(&set_syncs(17)), 17);
|
||
|
||
// Exactly half intact → classified scrambled (16 > 16 is false).
|
||
assert!(ts_sync_destroyed(&set_syncs(16)));
|
||
// One past half → classified clear.
|
||
assert!(!ts_sync_destroyed(&set_syncs(17)));
|
||
}
|
||
|
||
#[test]
|
||
fn scramble_detection_extremes() {
|
||
// Detection semantics for the clear-cut cases must be preserved:
|
||
// a fully-clear unit (all 32 syncs) is NOT scrambled; a unit with no
|
||
// syncs (fully scrambled body) IS scrambled.
|
||
let mut clear = vec![0u8; ALIGNED_UNIT_LEN];
|
||
let mut off = 4;
|
||
while off < ALIGNED_UNIT_LEN {
|
||
clear[off] = TS_SYNC;
|
||
off += BD_SOURCE_PACKET_BYTES;
|
||
}
|
||
assert_eq!(ts_sync_count(&clear), 32);
|
||
assert!(
|
||
!ts_sync_destroyed(&clear),
|
||
"fully-clear unit → not scrambled"
|
||
);
|
||
|
||
let scrambled = vec![0u8; ALIGNED_UNIT_LEN];
|
||
assert_eq!(ts_sync_count(&scrambled), 0);
|
||
assert!(ts_sync_destroyed(&scrambled), "no syncs → scrambled");
|
||
}
|
||
|
||
#[test]
|
||
fn test_aes_cbc_roundtrip() {
|
||
let key = [
|
||
0x11u8, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE,
|
||
0xFF, 0x00,
|
||
];
|
||
let original = vec![0x42u8; 128]; // 8 blocks
|
||
let mut data = original.clone();
|
||
|
||
// Encrypt with CBC manually (forward direction)
|
||
fn aes_cbc_encrypt(key: &[u8; 16], data: &mut [u8]) {
|
||
let cipher = Aes128::new(GenericArray::from_slice(key));
|
||
let mut prev = super::AACS_IV;
|
||
let num_blocks = data.len() / 16;
|
||
for i in 0..num_blocks {
|
||
let offset = i * 16;
|
||
for j in 0..16 {
|
||
data[offset + j] ^= prev[j];
|
||
}
|
||
let mut block = GenericArray::clone_from_slice(&data[offset..offset + 16]);
|
||
cipher.encrypt_block(&mut block);
|
||
data[offset..offset + 16].copy_from_slice(&block);
|
||
prev.copy_from_slice(&data[offset..offset + 16]);
|
||
}
|
||
}
|
||
|
||
aes_cbc_encrypt(&key, &mut data);
|
||
assert_ne!(data, original); // should be different after encrypt
|
||
|
||
super::aes_cbc_decrypt(&key, &mut data);
|
||
assert_eq!(data, original); // should match after roundtrip
|
||
}
|
||
|
||
#[test]
|
||
fn test_decrypt_unit_synthetic() {
|
||
// Build a fake 6144-byte aligned unit with known TS sync pattern,
|
||
// encrypt it with the AACS algorithm, then decrypt and verify.
|
||
let unit_key = [0xAAu8; 16];
|
||
|
||
// Build plaintext unit with TS sync bytes every 192 bytes starting at offset 4
|
||
let mut plain = vec![0u8; ALIGNED_UNIT_LEN];
|
||
let mut offset = 4;
|
||
while offset < ALIGNED_UNIT_LEN {
|
||
plain[offset] = TS_SYNC;
|
||
offset += BD_SOURCE_PACKET_BYTES;
|
||
}
|
||
// Flag the unit encrypted via the CPI bits (byte 0) — the authoritative
|
||
// gate `decrypt_unit` now consults. Set before key derivation so the
|
||
// recovered plaintext header matches.
|
||
plain[0] |= 0xC0;
|
||
|
||
// Now encrypt bytes 16..6143 using the AACS algorithm (reverse of decrypt)
|
||
let header: [u8; 16] = plain[..16].try_into().unwrap();
|
||
let derived = aes_ecb_encrypt(&unit_key, &header);
|
||
let mut encrypt_key = [0u8; 16];
|
||
for i in 0..16 {
|
||
encrypt_key[i] = derived[i] ^ header[i];
|
||
}
|
||
|
||
// CBC encrypt bytes 16..6143
|
||
let cipher = Aes128::new(GenericArray::from_slice(&encrypt_key));
|
||
let mut prev = AACS_IV;
|
||
let num_blocks = (ALIGNED_UNIT_LEN - 16) / 16;
|
||
for i in 0..num_blocks {
|
||
let off = 16 + i * 16;
|
||
for j in 0..16 {
|
||
plain[off + j] ^= prev[j];
|
||
}
|
||
let mut block = GenericArray::clone_from_slice(&plain[off..off + 16]);
|
||
cipher.encrypt_block(&mut block);
|
||
plain[off..off + 16].copy_from_slice(&block);
|
||
prev.copy_from_slice(&plain[off..off + 16]);
|
||
}
|
||
|
||
// Now plain contains encrypted data. Decrypt it.
|
||
let mut unit = plain;
|
||
assert!(ts_sync_destroyed(&unit));
|
||
assert!(decrypt_unit(&mut unit, &unit_key));
|
||
assert!(!ts_sync_destroyed(&unit)); // decrypted: TS syncs restored
|
||
|
||
// Verify TS sync bytes
|
||
let mut count = 0;
|
||
let mut off = 4;
|
||
while off < ALIGNED_UNIT_LEN {
|
||
if unit[off] == TS_SYNC {
|
||
count += 1;
|
||
}
|
||
off += BD_SOURCE_PACKET_BYTES;
|
||
}
|
||
// Assert against the single canonical packet count, not the old
|
||
// `(len - 4) / 192 + 1` form that `ts_packet_total` corrected away from.
|
||
assert_eq!(count, ts_packet_total(&unit));
|
||
}
|
||
|
||
// ── Helpers for the hardening tests below ──────────────────────────────
|
||
|
||
/// Encrypt an aligned unit in place with the AACS unit-decrypt
|
||
/// algorithm run in reverse, so [`decrypt_unit`] with the same
|
||
/// `unit_key` recovers the plaintext. This is the exact inverse of
|
||
/// the production decrypt: derive `decrypt_key = AES-ECB-E(unit_key,
|
||
/// header) XOR header`, then CBC-encrypt bytes 16..6144 under the
|
||
/// fixed AACS IV.
|
||
fn aacs_encrypt_unit(unit: &mut [u8], unit_key: &[u8; 16]) {
|
||
// Set the CPI bits (top 2 of byte 0) so the unit reads as encrypted under
|
||
// `aacs_unit_encrypted` — done BEFORE key derivation so the plaintext
|
||
// header the real decrypt recovers matches what we encrypt under.
|
||
unit[0] |= 0xC0;
|
||
let header: [u8; 16] = unit[..16].try_into().unwrap();
|
||
let derived = aes_ecb_encrypt(unit_key, &header);
|
||
let mut k = [0u8; 16];
|
||
for i in 0..16 {
|
||
k[i] = derived[i] ^ header[i];
|
||
}
|
||
let cipher = Aes128::new(GenericArray::from_slice(&k));
|
||
let mut prev = AACS_IV;
|
||
let num_blocks = (ALIGNED_UNIT_LEN - 16) / 16;
|
||
for i in 0..num_blocks {
|
||
let off = 16 + i * 16;
|
||
for j in 0..16 {
|
||
unit[off + j] ^= prev[j];
|
||
}
|
||
let mut block = GenericArray::clone_from_slice(&unit[off..off + 16]);
|
||
cipher.encrypt_block(&mut block);
|
||
unit[off..off + 16].copy_from_slice(&block);
|
||
prev.copy_from_slice(&unit[off..off + 16]);
|
||
}
|
||
}
|
||
|
||
/// Build a clear aligned unit with TS sync bytes at offset 4 + k*192.
|
||
fn clear_unit() -> Vec<u8> {
|
||
let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
|
||
let mut off = 4;
|
||
while off < ALIGNED_UNIT_LEN {
|
||
unit[off] = TS_SYNC;
|
||
off += BD_SOURCE_PACKET_BYTES;
|
||
}
|
||
unit
|
||
}
|
||
|
||
// ── AES-ECB KAT (FIPS-197 Appendix C.1) ────────────────────────────────
|
||
|
||
#[test]
|
||
fn aes_ecb_matches_fips197_known_answer() {
|
||
// FIPS-197 Appendix C.1 AES-128 KAT:
|
||
// key = 000102030405060708090a0b0c0d0e0f
|
||
// plaintext = 00112233445566778899aabbccddeeff
|
||
// ciphertext= 69c4e0d86a7b0430d8cdb78070b4c55a
|
||
// This pins the AES primitive against a published vector — a wrong
|
||
// cipher (or a key/plaintext byte-order slip) fails it.
|
||
let key = [
|
||
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D,
|
||
0x0E, 0x0F,
|
||
];
|
||
let pt = [
|
||
0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD,
|
||
0xEE, 0xFF,
|
||
];
|
||
let expected = [
|
||
0x69, 0xC4, 0xE0, 0xD8, 0x6A, 0x7B, 0x04, 0x30, 0xD8, 0xCD, 0xB7, 0x80, 0x70, 0xB4,
|
||
0xC5, 0x5A,
|
||
];
|
||
assert_eq!(aes_ecb_encrypt(&key, &pt), expected);
|
||
// And decrypt is the exact inverse.
|
||
assert_eq!(aes_ecb_decrypt(&key, &expected), pt);
|
||
}
|
||
|
||
// ── CBC decrypt: first-block uses fixed AACS IV ────────────────────────
|
||
|
||
#[test]
|
||
fn cbc_decrypt_first_block_xors_aacs_iv() {
|
||
// CBC: P[0] = AES-D(K, C[0]) XOR IV, and the IV is the fixed AACS
|
||
// constant (not zero). Encrypt a single block forward with IV, then
|
||
// confirm aes_cbc_decrypt recovers it — proving the IV used on block
|
||
// 0 is exactly AACS_IV. A mutation that swaps AACS_IV for [0u8;16]
|
||
// makes the recovered block wrong.
|
||
let key = [0x24u8; 16];
|
||
let plain = [0x5Au8; 16];
|
||
// Forward CBC for one block: C = AES-E(K, P XOR IV).
|
||
let mut x = plain;
|
||
for j in 0..16 {
|
||
x[j] ^= AACS_IV[j];
|
||
}
|
||
let ct = aes_ecb_encrypt(&key, &x);
|
||
let mut buf = ct;
|
||
aes_cbc_decrypt(&key, &mut buf);
|
||
assert_eq!(buf, plain, "block-0 CBC must XOR the fixed AACS IV");
|
||
}
|
||
|
||
// ── CBC decrypt KAT (NIST SP 800-38A F.2.2, AES-128-CBC) ───────────────
|
||
|
||
#[test]
|
||
fn aes_cbc_decrypt_matches_nist_sp800_38a_f2_2() {
|
||
// NIST SP 800-38A Appendix F.2.2 (CBC-AES128.Decrypt) published vector:
|
||
// Key = 2b7e151628aed2a6abf7158809cf4f3c
|
||
// IV = 000102030405060708090a0b0c0d0e0f
|
||
// CT = 7649abac8119b246cee98e9b12e9197d (block 0)
|
||
// 5086cb9b507219ee95db113a917678b2 (block 1)
|
||
// 73bed6b8e3c1743b7116e69e22229516 (block 2)
|
||
// 3ff1caa1681fac09120eca307586e1a7 (block 3)
|
||
// PT = 6bc1bee22e409f96e93d7e117393172a (block 0)
|
||
// ae2d8a571e03ac9c9eb76fac45af8e51 (block 1)
|
||
// 30c81c46a35ce411e5fbc1191a0a52ef (block 2)
|
||
// f69f2445df4f9b17ad2b417be66c3710 (block 3)
|
||
//
|
||
// `aes_cbc_decrypt` hardwires the fixed AACS IV for block 0 (it never
|
||
// takes a caller IV), so:
|
||
// * Blocks 1..=3 are independent of the IV — they MUST equal the NIST
|
||
// plaintext byte-for-byte (P[i] = AES-D(K, C[i]) XOR C[i-1]). This
|
||
// pins the real reverse-order CBC chaining against a published KAT.
|
||
// * Block 0 = AES-D(K, C[0]) XOR AACS_IV = NIST_PT[0] XOR NIST_IV
|
||
// XOR AACS_IV — the documented IV substitution. Asserting this exact
|
||
// relation pins both the AES decrypt of C[0] AND that block 0 uses
|
||
// AACS_IV (a swap to [0u8;16] or a chaining bug fails it).
|
||
let key = [
|
||
0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF,
|
||
0x4F, 0x3C,
|
||
];
|
||
let nist_iv = [
|
||
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D,
|
||
0x0E, 0x0F,
|
||
];
|
||
// Byte arrays kept narrow (≤14 bytes/line) so the secret-scanner's
|
||
// 32-nibble-per-line heuristic doesn't flag these published vectors as
|
||
// key material (same layout the existing FIPS-197 / CMAC KATs use).
|
||
let ciphertext: [u8; 64] = [
|
||
0x76, 0x49, 0xAB, 0xAC, 0x81, 0x19, 0xB2, 0x46, 0xCE, 0xE9, 0x8E, 0x9B, 0x12, 0xE9,
|
||
0x19, 0x7D, 0x50, 0x86, 0xCB, 0x9B, 0x50, 0x72, 0x19, 0xEE, 0x95, 0xDB, 0x11, 0x3A,
|
||
0x91, 0x76, 0x78, 0xB2, 0x73, 0xBE, 0xD6, 0xB8, 0xE3, 0xC1, 0x74, 0x3B, 0x71, 0x16,
|
||
0xE6, 0x9E, 0x22, 0x22, 0x95, 0x16, 0x3F, 0xF1, 0xCA, 0xA1, 0x68, 0x1F, 0xAC, 0x09,
|
||
0x12, 0x0E, 0xCA, 0x30, 0x75, 0x86, 0xE1, 0xA7,
|
||
];
|
||
let nist_plaintext: [u8; 64] = [
|
||
0x6B, 0xC1, 0xBE, 0xE2, 0x2E, 0x40, 0x9F, 0x96, 0xE9, 0x3D, 0x7E, 0x11, 0x73, 0x93,
|
||
0x17, 0x2A, 0xAE, 0x2D, 0x8A, 0x57, 0x1E, 0x03, 0xAC, 0x9C, 0x9E, 0xB7, 0x6F, 0xAC,
|
||
0x45, 0xAF, 0x8E, 0x51, 0x30, 0xC8, 0x1C, 0x46, 0xA3, 0x5C, 0xE4, 0x11, 0xE5, 0xFB,
|
||
0xC1, 0x19, 0x1A, 0x0A, 0x52, 0xEF, 0xF6, 0x9F, 0x24, 0x45, 0xDF, 0x4F, 0x9B, 0x17,
|
||
0xAD, 0x2B, 0x41, 0x7B, 0xE6, 0x6C, 0x37, 0x10,
|
||
];
|
||
|
||
let mut buf = ciphertext;
|
||
aes_cbc_decrypt(&key, &mut buf);
|
||
|
||
// Blocks 1..=3: exact match against the published NIST plaintext.
|
||
assert_eq!(
|
||
&buf[16..64],
|
||
&nist_plaintext[16..64],
|
||
"CBC chaining (blocks 1..3) must match NIST SP 800-38A F.2.2 plaintext"
|
||
);
|
||
|
||
// Block 0: NIST_PT[0] XOR NIST_IV XOR AACS_IV (the fixed-IV substitution).
|
||
let mut expected_block0 = [0u8; 16];
|
||
for i in 0..16 {
|
||
expected_block0[i] = nist_plaintext[i] ^ nist_iv[i] ^ AACS_IV[i];
|
||
}
|
||
assert_eq!(
|
||
&buf[0..16],
|
||
&expected_block0,
|
||
"block-0 plaintext must equal NIST PT XOR NIST IV XOR AACS_IV (fixed-IV path)"
|
||
);
|
||
}
|
||
|
||
// ── decrypt_unit: full round trip restores TS syncs ────────────────────
|
||
|
||
#[test]
|
||
fn decrypt_unit_roundtrip_restores_all_syncs() {
|
||
// Encrypt a clear unit, confirm it reads as scrambled, then decrypt
|
||
// and confirm every TS sync byte at the 192-byte stride is restored.
|
||
let unit_key = [0x37u8; 16];
|
||
let mut unit = clear_unit();
|
||
aacs_encrypt_unit(&mut unit, &unit_key);
|
||
assert!(
|
||
ts_sync_destroyed(&unit),
|
||
"encrypted unit must look scrambled"
|
||
);
|
||
|
||
assert!(decrypt_unit(&mut unit, &unit_key));
|
||
// All 32 stride positions carry sync after decrypt.
|
||
assert_eq!(ts_sync_count(&unit), ts_packet_total(&unit));
|
||
assert!(!ts_sync_destroyed(&unit));
|
||
}
|
||
|
||
#[test]
|
||
fn decrypt_unit_wrong_key_fails_and_does_not_falsely_clear() {
|
||
// A wrong unit key fails verify_ts (the body stays scrambled), so
|
||
// decrypt_unit returns false. Grounds the brute-force gate: a bad key
|
||
// must NOT report success.
|
||
let good = [0x11u8; 16];
|
||
let bad = [0x22u8; 16];
|
||
let mut unit = clear_unit();
|
||
aacs_encrypt_unit(&mut unit, &good);
|
||
assert!(!decrypt_unit(&mut unit, &bad), "wrong key must not verify");
|
||
}
|
||
|
||
#[test]
|
||
fn decrypt_unit_rejects_short_unit() {
|
||
// unit.len() < ALIGNED_UNIT_LEN → false (no panic on the 16.. slice).
|
||
let mut short = vec![0u8; ALIGNED_UNIT_LEN - 1];
|
||
assert!(!decrypt_unit(&mut short, &[0u8; 16]));
|
||
}
|
||
|
||
#[test]
|
||
fn decrypt_unit_only_touches_bytes_16_onward() {
|
||
// The first 16 bytes are the plaintext TP_extra header and must be
|
||
// left untouched by decrypt (only unit[16..] is CBC-processed).
|
||
let unit_key = [0x9Au8; 16];
|
||
let mut clear = clear_unit();
|
||
// Put a distinctive header so we can confirm it survives. Byte 0 carries
|
||
// both CPI bits (0xE0) so it is stable under the fixture's `|= 0xC0`.
|
||
clear[..16].copy_from_slice(&[
|
||
0xE0, 0xA1, 0xA2, 0xA3, 0x47, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD,
|
||
0xAE, 0xAF,
|
||
]);
|
||
let header_before: [u8; 16] = clear[..16].try_into().unwrap();
|
||
let mut unit = clear;
|
||
aacs_encrypt_unit(&mut unit, &unit_key);
|
||
// Encryption also leaves the header untouched (only 16.. is encrypted).
|
||
assert_eq!(&unit[..16], &header_before);
|
||
decrypt_unit(&mut unit, &unit_key);
|
||
assert_eq!(
|
||
&unit[..16],
|
||
&header_before,
|
||
"header bytes must be preserved"
|
||
);
|
||
}
|
||
|
||
// ── decrypt_unit_try_keys: AlreadyClear vs DecryptedWith vs None ───────
|
||
|
||
#[test]
|
||
fn try_keys_reports_already_clear_without_consuming_a_key() {
|
||
// A clear unit returns AlreadyClear even with an empty key list — the
|
||
// old Option<usize> form conflated this with Some(0). Grounds the
|
||
// UnitKeyResult enum distinction.
|
||
let mut unit = clear_unit();
|
||
assert_eq!(
|
||
decrypt_unit_try_keys(&mut unit, &[]),
|
||
Some(UnitKeyResult::AlreadyClear)
|
||
);
|
||
}
|
||
|
||
#[test]
|
||
fn try_keys_reports_correct_index_among_several() {
|
||
// Three keys, only the 3rd (index 2) decrypts → DecryptedWith(2).
|
||
let real = [0x44u8; 16];
|
||
let mut unit = clear_unit();
|
||
aacs_encrypt_unit(&mut unit, &real);
|
||
let keys = [[0x01u8; 16], [0x02u8; 16], real];
|
||
assert_eq!(
|
||
decrypt_unit_try_keys(&mut unit, &keys),
|
||
Some(UnitKeyResult::DecryptedWith(2))
|
||
);
|
||
assert!(
|
||
!ts_sync_destroyed(&unit),
|
||
"unit must be clear after the hit"
|
||
);
|
||
}
|
||
|
||
#[test]
|
||
fn try_keys_restores_original_bytes_on_total_failure() {
|
||
// When no key works, the unit must be byte-identical to the input
|
||
// (the function CBC-mangles it per attempt, then restores). A buggy
|
||
// restore would leave the unit corrupted — silent data damage.
|
||
let real = [0x55u8; 16];
|
||
let mut unit = clear_unit();
|
||
aacs_encrypt_unit(&mut unit, &real);
|
||
let snapshot = unit.clone();
|
||
let wrong = [[0xAAu8; 16], [0xBBu8; 16]];
|
||
assert_eq!(decrypt_unit_try_keys(&mut unit, &wrong), None);
|
||
assert_eq!(unit, snapshot, "failed try must restore the original bytes");
|
||
}
|
||
|
||
// ── CPI gate: the authoritative encrypted-vs-clear decision ────────────
|
||
|
||
#[test]
|
||
fn cpi_gate_clear_flag_passes_through_even_when_body_looks_scrambled() {
|
||
// THE false-fail fix: a unit whose CPI bits are clear (byte 0 & 0xC0 == 0)
|
||
// is plaintext by spec, even if its body has no TS syncs (non-TS clear
|
||
// data, or a mis-probed body). `decrypt_unit` must pass it through
|
||
// untouched and report success — never attempt a decrypt that would fail.
|
||
let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
|
||
// Body looks scrambled (no syncs at the stride) but byte 0 stays 0x00.
|
||
for (i, b) in unit.iter_mut().enumerate().skip(16) {
|
||
*b = (i as u8).wrapping_mul(31) | 1; // never 0x47 at the sync stride
|
||
}
|
||
assert!(ts_sync_destroyed(&unit), "body has no syncs");
|
||
assert!(!aacs_unit_encrypted(&unit), "CPI clear");
|
||
assert!(
|
||
!aacs_unit_needs_decrypt(&unit),
|
||
"CPI-clear ⇒ no decrypt attempt"
|
||
);
|
||
let snapshot = unit.clone();
|
||
// Any key: passthrough success, bytes untouched (no false DecryptFailed).
|
||
assert!(decrypt_unit(&mut unit, &[0xABu8; 16]));
|
||
assert_eq!(unit, snapshot, "CPI-clear unit must be left byte-identical");
|
||
assert_eq!(
|
||
decrypt_unit_try_keys(&mut unit, &[[0xABu8; 16]]),
|
||
Some(UnitKeyResult::AlreadyClear),
|
||
"CPI-clear unit consumes no key"
|
||
);
|
||
}
|
||
|
||
#[test]
|
||
fn cpi_gate_set_flag_decrypts_and_needs_decrypt_is_idempotent() {
|
||
// A CPI-set encrypted unit decrypts with the right key. CPI lives in the
|
||
// plaintext header, so it survives decryption — `aacs_unit_encrypted`
|
||
// still reports true afterward, but `aacs_unit_needs_decrypt` flips to
|
||
// false (syncs restored), keeping the re-decrypt paths idempotent.
|
||
let key = [0x5au8; 16];
|
||
let mut unit = clear_unit();
|
||
aacs_encrypt_unit(&mut unit, &key); // sets CPI + scrambles body
|
||
assert!(aacs_unit_encrypted(&unit), "CPI set");
|
||
assert!(aacs_unit_needs_decrypt(&unit), "flagged + still scrambled");
|
||
|
||
assert!(decrypt_unit(&mut unit, &key), "right key decrypts");
|
||
assert!(
|
||
aacs_unit_encrypted(&unit),
|
||
"CPI bits live in the preserved header ⇒ still set post-decrypt"
|
||
);
|
||
assert!(
|
||
!aacs_unit_needs_decrypt(&unit),
|
||
"syncs restored ⇒ no further decrypt attempt (idempotent re-decrypt)"
|
||
);
|
||
}
|
||
|
||
// ── unit_key_validates: matches decrypt_unit's verdict exactly ─────────
|
||
|
||
#[test]
|
||
fn unit_key_validates_agrees_with_decrypt_unit() {
|
||
// The fast 1-byte gate's accept/reject set must be identical to the
|
||
// authoritative decrypt_unit. Confirm: correct key → true on both;
|
||
// wrong key → false on both.
|
||
let good = [0x6Au8; 16];
|
||
let bad = [0x6Bu8; 16];
|
||
let mut enc = clear_unit();
|
||
aacs_encrypt_unit(&mut enc, &good);
|
||
|
||
assert!(unit_key_validates(&enc, &good));
|
||
let mut probe = enc.clone();
|
||
assert!(decrypt_unit(&mut probe, &good));
|
||
|
||
assert!(!unit_key_validates(&enc, &bad));
|
||
let mut probe2 = enc.clone();
|
||
assert!(!decrypt_unit(&mut probe2, &bad));
|
||
}
|
||
|
||
#[test]
|
||
fn unit_is_clean_ts_is_strict_all_32_syncs() {
|
||
// Standards-correct gate (libaacs `_verify_ts`): EVERY one of the 32
|
||
// packet syncs is required. A fully-synced clear unit passes.
|
||
let clear = clear_unit();
|
||
assert!(unit_is_clean_ts(&clear), "all-32-sync unit is clean");
|
||
|
||
// Drop a SINGLE sync (packet 17 of 32). 31/32 remain, so the majority
|
||
// heuristic still passes — that is exactly the silent-corruption hole.
|
||
// The strict gate must REJECT it.
|
||
let mut one_missing = clear_unit();
|
||
one_missing[17 * BD_SOURCE_PACKET_BYTES + 4] = 0x00;
|
||
assert!(
|
||
ts_syncs_intact(&one_missing),
|
||
"majority heuristic still passes one missing sync (the hole)"
|
||
);
|
||
assert!(
|
||
!unit_is_clean_ts(&one_missing),
|
||
"strict gate rejects even one missing sync"
|
||
);
|
||
|
||
// A correctly decrypted unit is clean; a wrong-key decrypt is not.
|
||
let key = [0x33u8; 16];
|
||
let mut enc = clear_unit();
|
||
aacs_encrypt_unit(&mut enc, &key);
|
||
let mut good = enc.clone();
|
||
decrypt_unit(&mut good, &key);
|
||
assert!(unit_is_clean_ts(&good), "right-key decrypt yields clean TS");
|
||
let mut wrong = enc.clone();
|
||
decrypt_unit(&mut wrong, &[0x34u8; 16]);
|
||
assert!(
|
||
!unit_is_clean_ts(&wrong),
|
||
"wrong-key decrypt must fail the strict gate"
|
||
);
|
||
|
||
// Short buffer is never vacuously clean.
|
||
assert!(!unit_is_clean_ts(&clear[..ALIGNED_UNIT_LEN - 1]));
|
||
}
|
||
|
||
#[test]
|
||
fn unit_key_validates_is_non_mutating() {
|
||
// The accelerator must never write its input (it operates on the
|
||
// ciphertext and confirms on a copy). A mutation that decrypted in
|
||
// place would corrupt the caller's buffer.
|
||
let good = [0x7Cu8; 16];
|
||
let mut enc = clear_unit();
|
||
aacs_encrypt_unit(&mut enc, &good);
|
||
let snapshot = enc.clone();
|
||
let _ = unit_key_validates(&enc, &good);
|
||
assert_eq!(enc, snapshot, "unit_key_validates must not mutate input");
|
||
}
|
||
|
||
#[test]
|
||
fn unit_key_validates_rejects_short_unit() {
|
||
let short = vec![0u8; ALIGNED_UNIT_LEN - 16];
|
||
assert!(!unit_key_validates(&short, &[0u8; 16]));
|
||
}
|
||
|
||
// ── bus decryption (AACS 2.0 / UHD) ────────────────────────────────────
|
||
|
||
#[test]
|
||
fn decrypt_bus_roundtrips_per_sector_skipping_first_16_bytes() {
|
||
// Bus encryption CBC-encrypts bytes 16..2048 of EACH 2048-byte sector
|
||
// (3 sectors per aligned unit), leaving the first 16 plaintext. Build
|
||
// the forward transform, then confirm decrypt_bus inverts it and
|
||
// leaves each sector's first 16 bytes untouched.
|
||
let rdk = [0x13u8; 16];
|
||
let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
|
||
// Fill with a recognisable pattern.
|
||
for (i, b) in unit.iter_mut().enumerate() {
|
||
*b = (i % 251) as u8;
|
||
}
|
||
let plain = unit.clone();
|
||
|
||
// Forward: CBC-encrypt unit[s+16 .. s+2048] per sector under AACS IV.
|
||
let cipher = Aes128::new(GenericArray::from_slice(&rdk));
|
||
for s in (0..ALIGNED_UNIT_LEN).step_by(SECTOR_BYTES) {
|
||
let mut prev = AACS_IV;
|
||
let body = s + 16;
|
||
let end = s + SECTOR_BYTES;
|
||
let nblocks = (end - body) / 16;
|
||
for i in 0..nblocks {
|
||
let off = body + i * 16;
|
||
for j in 0..16 {
|
||
unit[off + j] ^= prev[j];
|
||
}
|
||
let mut blk = GenericArray::clone_from_slice(&unit[off..off + 16]);
|
||
cipher.encrypt_block(&mut blk);
|
||
unit[off..off + 16].copy_from_slice(&blk);
|
||
prev.copy_from_slice(&unit[off..off + 16]);
|
||
}
|
||
}
|
||
assert_ne!(unit, plain, "forward bus-encrypt must change the body");
|
||
|
||
decrypt_bus(&mut unit, &rdk);
|
||
assert_eq!(
|
||
unit, plain,
|
||
"decrypt_bus must invert per-sector bus encrypt"
|
||
);
|
||
// Each sector's first 16 bytes equal the original (never touched).
|
||
for s in (0..ALIGNED_UNIT_LEN).step_by(SECTOR_BYTES) {
|
||
assert_eq!(&unit[s..s + 16], &plain[s..s + 16]);
|
||
}
|
||
}
|
||
|
||
// ── decrypt_unit_full: bus-then-AACS ordering, and clear passthrough ───
|
||
|
||
#[test]
|
||
fn decrypt_unit_full_passthrough_when_already_clear() {
|
||
// A clear unit returns true and is not modified, regardless of keys.
|
||
let mut unit = clear_unit();
|
||
let snapshot = unit.clone();
|
||
assert!(decrypt_unit_full(
|
||
&mut unit,
|
||
&[0u8; 16],
|
||
Some(&[0xFFu8; 16])
|
||
));
|
||
assert_eq!(unit, snapshot, "clear unit must pass through untouched");
|
||
}
|
||
|
||
#[test]
|
||
fn decrypt_unit_full_applies_bus_then_aacs() {
|
||
// AACS 2.0 pipeline: content is first AACS-unit-encrypted, then
|
||
// bus-encrypted on top. Decrypt must undo bus FIRST, then AACS.
|
||
// Build that exact two-layer ciphertext and confirm full recovery.
|
||
let unit_key = [0x21u8; 16];
|
||
let rdk = [0x84u8; 16];
|
||
|
||
let mut unit = clear_unit();
|
||
// Layer 1: AACS unit-encrypt.
|
||
aacs_encrypt_unit(&mut unit, &unit_key);
|
||
// Layer 2: bus-encrypt on top (per-sector, bytes 16..2048).
|
||
let cipher = Aes128::new(GenericArray::from_slice(&rdk));
|
||
for s in (0..ALIGNED_UNIT_LEN).step_by(SECTOR_BYTES) {
|
||
let mut prev = AACS_IV;
|
||
for i in 0..((SECTOR_BYTES - 16) / 16) {
|
||
let off = s + 16 + i * 16;
|
||
for j in 0..16 {
|
||
unit[off + j] ^= prev[j];
|
||
}
|
||
let mut blk = GenericArray::clone_from_slice(&unit[off..off + 16]);
|
||
cipher.encrypt_block(&mut blk);
|
||
unit[off..off + 16].copy_from_slice(&blk);
|
||
prev.copy_from_slice(&unit[off..off + 16]);
|
||
}
|
||
}
|
||
assert!(ts_sync_destroyed(&unit));
|
||
assert!(decrypt_unit_full(&mut unit, &unit_key, Some(&rdk)));
|
||
assert_eq!(ts_sync_count(&unit), ts_packet_total(&unit));
|
||
}
|
||
|
||
// ── ts_sync_destroyed / ts_sync_count edge cases ───────────────────────
|
||
|
||
#[test]
|
||
fn ts_sync_destroyed_false_for_sub_unit_length() {
|
||
// The function guards on `len >= ALIGNED_UNIT_LEN` first; anything
|
||
// shorter is reported NOT scrambled (so the decrypt gate skips it)
|
||
// rather than indexing past the end.
|
||
assert!(!ts_sync_destroyed(&[]));
|
||
assert!(!ts_sync_destroyed(&vec![0u8; ALIGNED_UNIT_LEN - 1]));
|
||
// A scrambled-looking buffer that is one byte short is still "not
|
||
// scrambled" by the length guard.
|
||
let mut almost = vec![0u8; ALIGNED_UNIT_LEN - 1];
|
||
almost[4] = 0x00; // no syncs
|
||
assert!(!ts_sync_destroyed(&almost));
|
||
}
|
||
|
||
#[test]
|
||
fn ts_sync_count_only_samples_the_192_byte_stride() {
|
||
// A 0x47 placed OFF the stride (e.g. offset 5) must not be counted —
|
||
// the detector samples exactly offset 4, 196, 388, ... A mutation that
|
||
// scanned every byte would over-count and misclassify scrambled units.
|
||
let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
|
||
unit[5] = TS_SYNC; // off-stride
|
||
unit[197] = TS_SYNC; // off-stride
|
||
assert_eq!(ts_sync_count(&unit), 0, "off-stride 0x47 must not count");
|
||
unit[4] = TS_SYNC; // on-stride
|
||
assert_eq!(ts_sync_count(&unit), 1);
|
||
}
|
||
|
||
#[test]
|
||
fn ts_packet_total_for_various_lengths() {
|
||
// total = len / 192 (BD-TS packet size). Pin a few lengths.
|
||
assert_eq!(ts_packet_total(&[0u8; 192]), 1);
|
||
assert_eq!(ts_packet_total(&[0u8; 384]), 2);
|
||
assert_eq!(ts_packet_total(&[0u8; 191]), 0);
|
||
// 6144 = 32 packets.
|
||
assert_eq!(ts_packet_total(&[0u8; ALIGNED_UNIT_LEN]), 32);
|
||
}
|
||
}
|