v0.25.13: DrmScheme dispatcher + AACS 2.1 framework + libredrive cleanup
- Introduce DrmScheme enum (Css/Aacs10/Aacs20/Aacs21) + drm module with uniform detect/load dispatch across all four protection schemes. - Land AACS 2.1 Media Key Variant framework in aacs::variants: chain derivation, MKB record types 0x82/0x83, bit-0x02 SoftKCD and bit-0x04 online-challenge detection. Aacs21 dispatcher arm wired but commented out pending validation against a Variant-scheme disc. - Replace aacs2: bool with AacsVersion enum across ContentCertificate, UnitKeyFile, ResolvedKeys. resolve_keys splits into _v1/_v2/_v21. - Delete the libredrive raw-read VID shortcut from do_handshake; the drive enforces the AGID requirement regardless of firmware-upload state, so the shortcut spuriously dispatched E7017 instead of surfacing the real downstream walls.
This commit is contained in:
MattJackson
+246
-78
@@ -3,6 +3,38 @@
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use super::decrypt::aes_ecb_decrypt;
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use super::keydb::{DeviceKey, KeyDb};
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// ── AACS version ────────────────────────────────────────────────────────────
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/// AACS protection generation a disc carries.
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///
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/// The content cert byte distinguishes V10 (`0x00`) from V20 (`0x01`). V21
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/// cannot be detected from the cert alone — a V21 disc carries a V20 cert
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/// and is upgraded to `V21` only after the MKB walk turns up record types
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/// `0x82` / `0x83` (Media Key Variant Data and Variant Number).
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///
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/// Key-storage stride in `Unit_Key_RO.inf` is 48 bytes for V10 and 64
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/// bytes for V20 / V21.
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub enum AacsVersion {
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/// AACS 1.0 — original BD-ROM.
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V10,
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/// AACS 2.0 — UHD-BD, classical Media Key derivation.
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V20,
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/// AACS 2.1 — UHD-BD with Media Key Variant chain on top of V20.
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V21,
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}
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impl AacsVersion {
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/// Stride (in bytes) between successive encrypted unit keys in
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/// `Unit_Key_RO.inf`.
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fn unit_key_stride(self) -> usize {
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match self {
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AacsVersion::V10 => 48,
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AacsVersion::V20 | AacsVersion::V21 => 64,
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}
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}
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}
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// ── VUK derivation ──────────────────────────────────────────────────────────
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/// Derive VUK from Media Key and Volume ID.
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@@ -33,8 +65,8 @@ pub struct UnitKeyFile {
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pub num_bdmv_dir: u8,
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/// Whether SKB MKB is used
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pub use_skb_mkb: bool,
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/// Whether this is AACS 2.0
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pub aacs2: bool,
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/// AACS generation this file's stride matches
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pub version: AacsVersion,
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/// Encrypted unit keys (CPS unit number, encrypted key)
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pub encrypted_keys: Vec<(u32, [u8; 16])>,
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/// Title → CPS unit index mapping (title_idx → unit_key_idx)
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@@ -76,8 +108,8 @@ pub fn disc_hash_hex(hash: &[u8; 20]) -> String {
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/// [uk_pos..uk_pos+2] BE16: num_unit_keys
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/// [uk_pos+48..] encrypted keys, 16 bytes each
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/// AACS 1.0: 48-byte stride
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/// AACS 2.0: 64-byte stride (48 + 16 extra)
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pub fn parse_unit_key_ro(data: &[u8], aacs2: bool) -> Option<UnitKeyFile> {
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/// AACS 2.0 / 2.1: 64-byte stride (48 + 16 extra)
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pub fn parse_unit_key_ro(data: &[u8], version: AacsVersion) -> Option<UnitKeyFile> {
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if data.len() < 20 {
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return None;
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}
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@@ -103,14 +135,14 @@ pub fn parse_unit_key_ro(data: &[u8], aacs2: bool) -> Option<UnitKeyFile> {
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app_type,
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num_bdmv_dir,
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use_skb_mkb,
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aacs2,
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version,
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encrypted_keys: Vec::new(),
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title_cps_unit: Vec::new(),
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});
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}
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// Stride between keys
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let stride = if aacs2 { 64 } else { 48 };
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let stride = version.unit_key_stride();
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// Validate size
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let keys_start = uk_pos + 48; // first key at uk_pos + 48
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@@ -155,7 +187,7 @@ pub fn parse_unit_key_ro(data: &[u8], aacs2: bool) -> Option<UnitKeyFile> {
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app_type,
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num_bdmv_dir,
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use_skb_mkb,
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aacs2,
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version,
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encrypted_keys,
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title_cps_unit,
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})
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@@ -210,18 +242,11 @@ pub fn derive_media_key_from_pk(mkb: &[u8], processing_keys: &[[u8; 16]]) -> Opt
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/// Validate a processing key against a cvalue/UV pair.
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/// Returns the Media Key if valid.
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///
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/// Implements libaacs `_validate_pk` (aacs.c:98-133) per sgx.fail
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/// Appendix D.2 step 25:
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/// Steps:
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/// 1. `mk = AES-128D(pk, cvalue)`
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/// 2. `mk[12..16] ^= uv` (4 bytes XOR into the LAST 4 bytes only)
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/// 2. `mk[12..16] ^= uv` (4 bytes XOR into the last 4 bytes only)
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/// 3. `dec_vd = AES-128D(mk, mk_dv)`
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/// 4. If `dec_vd[0..8] == 01 23 45 67 89 AB CD EF` → valid.
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///
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/// Previous implementation XOR'd the full 16-byte cvalue back into mk
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/// (extra step not in libaacs), skipped the uv XOR entirely, and used
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/// AES-128E + 12-zero-byte check instead of AES-128D + magic. Net effect
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/// was that correct processing keys were rejected whenever `uv != 0`,
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/// which is essentially every real disc.
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fn validate_processing_key(
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pk: &[u8; 16],
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cvalue: &[u8],
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@@ -237,8 +262,7 @@ fn validate_processing_key(
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cv.copy_from_slice(&cvalue[..16]);
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let mut mk = aes_ecb_decrypt(pk, &cv);
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// Step 2: XOR uv into the LAST 4 bytes of mk (mk[12..16]).
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// sgx.fail D.2 step 25 and libaacs aacs.c:118-120.
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// Step 2: XOR uv into the last 4 bytes of mk (mk[12..16]).
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for a in 0..4 {
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mk[12 + a] ^= uv[a];
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}
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@@ -319,13 +343,6 @@ fn mkb_find_subdiff_records(mkb: &[u8]) -> Option<Vec<u8>> {
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/// signature. To stay correct on both lines we prefer `0x07` first (the
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/// AACS 2.x layout used by every modern UHD disc) and fall back to
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/// `0x05` for AACS 1.0 MKBs.
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///
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/// References:
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/// - libaacs `mkb_cvalues` (mkb.c:190-193) uses `0x05` exclusively.
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/// - sgx.fail Appendix D.5 walks an AACS 2.x MKB and confirms cvalues
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/// at `0x07`.
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/// - Empirically confirmed against our `aacs2-mkb-samples/`
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/// (Wicked / Civil War / Barbie v77 MKBs): cvalues at `0x07`.
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fn mkb_find_cvalues(mkb: &[u8]) -> Option<Vec<u8>> {
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if let Some(body) = find_record_body(mkb, 0x07) {
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return Some(body);
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@@ -585,8 +602,12 @@ pub struct ContentCert {
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pub bus_encryption: bool,
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/// Content Certificate ID (6 bytes)
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pub cc_id: [u8; 6],
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/// AACS version: false = AACS 1.0, true = AACS 2.0
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pub aacs2: bool,
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/// AACS generation indicated by the certificate type byte.
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///
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/// Cert type `0x00` → [`AacsVersion::V10`]; any other value →
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/// [`AacsVersion::V20`]. The certificate alone cannot distinguish
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/// V20 from V21 — Variant detection happens after the MKB walk.
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pub version: AacsVersion,
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}
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/// Parse a Content Certificate (ContentXXX.cer) file.
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@@ -599,7 +620,11 @@ pub fn parse_content_cert(data: &[u8]) -> Option<ContentCert> {
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// [0] certificate type (0x00 = AACS1, 0x01 = AACS2)
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// [1] bus_encryption_enabled (bit 0)
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// [2..8] cc_id (6 bytes)
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let aacs2 = data[0] != 0x00;
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let version = if data[0] == 0x00 {
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AacsVersion::V10
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} else {
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AacsVersion::V20
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};
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let bus_encryption = (data[1] & 0x01) != 0;
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let mut cc_id = [0u8; 6];
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cc_id.copy_from_slice(&data[2..8]);
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@@ -607,7 +632,7 @@ pub fn parse_content_cert(data: &[u8]) -> Option<ContentCert> {
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Some(ContentCert {
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bus_encryption,
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cc_id,
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aacs2,
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version,
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})
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}
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@@ -624,44 +649,172 @@ pub struct ResolvedKeys {
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pub unit_keys: Vec<(u32, [u8; 16])>,
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/// Title → CPS unit index mapping
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pub title_cps_unit: Vec<u16>,
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/// Whether AACS 2.0
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pub aacs2: bool,
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/// AACS generation that drove the resolution
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pub version: AacsVersion,
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/// Whether bus encryption is enabled (from Content Certificate)
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pub bus_encryption: bool,
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/// Which resolution path succeeded (1=KEYDB, 2=KEYDB derived, 3=PK, 4=DK)
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pub key_source: u8,
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}
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/// Resolve all AACS keys for a disc given:
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/// - Unit_Key_RO.inf raw data
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/// - Content Certificate raw data (optional, for AACS version detection)
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/// - Volume ID (from SCSI handshake)
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/// - KEYDB
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///
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/// Tries in order:
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/// 1. Disc hash → KEYDB → VUK (fast path)
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/// 2. KEYDB media key + volume ID → VUK (if disc hash not in KEYDB but MK is)
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/// 3. MKB + processing keys → media key → VUK (full derivation)
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pub fn resolve_keys(
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unit_key_ro_data: &[u8],
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content_cert_data: Option<&[u8]>,
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volume_id: &[u8; 16],
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keydb: &KeyDb,
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mkb_data: Option<&[u8]>,
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) -> Option<ResolvedKeys> {
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// Detect AACS version
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let aacs2 = content_cert_data
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.and_then(parse_content_cert)
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.map(|cc| cc.aacs2)
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.unwrap_or(false);
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/// Inputs shared by every classical-path resolver. References only —
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/// callers retain ownership of all buffers.
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pub struct ResolveContext<'a> {
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/// `Unit_Key_RO.inf` raw bytes.
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pub unit_key_ro: &'a [u8],
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/// Content Certificate raw bytes (optional — used for bus-encryption flag).
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pub content_cert: Option<&'a [u8]>,
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/// 16-byte Volume ID from SCSI handshake. `[0u8; 16]` is the
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/// "no VID" sentinel and disables paths 2/3/4.
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pub volume_id: &'a [u8; 16],
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/// Key database.
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pub keydb: &'a KeyDb,
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/// MKB raw bytes (optional — paths 3/4 require it).
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pub mkb: Option<&'a [u8]>,
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}
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let bus_encryption = content_cert_data
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/// AACS 1.0 key resolution. Parses `Unit_Key_RO.inf` with 48-byte
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/// stride. Tries paths 1 → 4 in order.
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pub fn resolve_keys_v1(ctx: &ResolveContext<'_>) -> Option<ResolvedKeys> {
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resolve_keys_classical(ctx, AacsVersion::V10)
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}
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/// AACS 2.0 key resolution. Parses `Unit_Key_RO.inf` with 64-byte
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/// stride. Tries paths 1 → 4 in order. When paths 3/4 succeed against
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/// an MKB carrying Variant records (`0x82` / `0x83`), the result's
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/// `version` is upgraded to [`AacsVersion::V21`] — derivation still
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/// runs through the classical V2 path; the V21-specific Variant chain
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/// is wired separately via [`resolve_keys_v21`].
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pub fn resolve_keys_v2(ctx: &ResolveContext<'_>) -> Option<ResolvedKeys> {
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let mut resolved = resolve_keys_classical(ctx, AacsVersion::V20)?;
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if let Some(mkb) = ctx.mkb {
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let recs = super::variants::walk_mkb(mkb);
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if super::variants::is_variant_mkb(&recs) {
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resolved.version = AacsVersion::V21;
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}
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}
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Some(resolved)
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}
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/// AACS 2.1 key resolution via the Media Key Variant chain.
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///
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/// This is wired but not reachable from the production dispatcher — the
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/// Variant chain still requires an integrator-supplied Key Correction
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/// Data constant (see [`super::variants::KEY_CORRECTION_DATA_PLACEHOLDER`])
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/// and an empirically-validated `VARIANTS[uv]` table. Until both are
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/// available, [`super::variants::derive_media_key_variant`] returns
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/// errors that this wrapper logs and converts to `None`.
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///
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/// The chain still passes the disc hash → KEYDB path (1) and the
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/// KEYDB-derived MK+VID path (2) before attempting variant derivation;
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/// V21 discs already in the keydb behave identically to V20.
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pub fn resolve_keys_v21(ctx: &ResolveContext<'_>) -> Option<ResolvedKeys> {
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// Paths 1 and 2 are version-agnostic — try them first via the
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// classical V20-stride parser.
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let uk_file = parse_unit_key_ro(ctx.unit_key_ro, AacsVersion::V20)?;
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let hash_hex = disc_hash_hex(&uk_file.disc_hash);
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let bus_encryption = ctx
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.content_cert
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.and_then(parse_content_cert)
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.map(|cc| cc.bus_encryption)
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.unwrap_or(false);
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// Parse Unit_Key_RO.inf
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let uk_file = parse_unit_key_ro(unit_key_ro_data, aacs2)?;
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let build = |vuk: [u8; 16], key_source: u8| -> ResolvedKeys {
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let unit_keys: Vec<(u32, [u8; 16])> = uk_file
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.encrypted_keys
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.iter()
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.map(|(num, enc_key)| (*num, decrypt_unit_key(&vuk, enc_key)))
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.collect();
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ResolvedKeys {
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disc_hash: uk_file.disc_hash,
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vuk,
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unit_keys,
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title_cps_unit: uk_file.title_cps_unit.clone(),
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version: AacsVersion::V21,
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bus_encryption,
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key_source,
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}
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};
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tracing::warn!(
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target: "freemkv::disc",
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phase = "resolve_keys_v21_start",
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bus_encryption,
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disc_hash = %hash_hex,
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mkb_present = ctx.mkb.is_some(),
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"resolve_keys_v21: starting"
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);
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if let Some(entry) = ctx.keydb.find_disc(&hash_hex) {
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if let Some(vuk) = entry.vuk {
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return Some(build(vuk, 1));
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}
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}
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if *ctx.volume_id == [0u8; 16] {
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tracing::warn!(
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target: "freemkv::disc",
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phase = "resolve_keys_v21_no_vid",
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"VID unavailable; v21 derivation requires VID"
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);
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return None;
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}
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for entry in ctx.keydb.disc_entries.values() {
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if let (Some(mk), Some(did)) = (entry.media_key, entry.disc_id) {
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if did == *ctx.volume_id {
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return Some(build(derive_vuk(&mk, ctx.volume_id), 2));
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}
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}
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}
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// Variant chain — walk MKB, derive Km via the Media Key Variant
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// chain, then derive VUK off Km and the disc's VID.
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let mkb = ctx.mkb?;
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let recs = super::variants::walk_mkb(mkb);
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match super::variants::derive_media_key_variant(
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&recs,
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&ctx.keydb.device_keys,
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&super::variants::KEY_CORRECTION_DATA_PLACEHOLDER,
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ctx.volume_id,
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) {
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Ok((_km, kvu)) => {
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tracing::warn!(
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target: "freemkv::disc",
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phase = "resolve_keys_v21_variant_ok",
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"Media Key Variant chain produced Km + Kvu"
|
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);
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Some(build(kvu, 4))
|
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}
|
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Err(e) => {
|
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tracing::warn!(
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target: "freemkv::disc",
|
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phase = "resolve_keys_v21_variant_err",
|
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error_code = %e,
|
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"Media Key Variant chain failed"
|
||||
);
|
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None
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Resolve all AACS keys for a disc using the classical (single-stage
|
||||
/// Media Key derivation) paths. Used by both V10 and V20.
|
||||
///
|
||||
/// Tries in order:
|
||||
/// 1. Disc hash → KEYDB → VUK (fast path, no VID required)
|
||||
/// 2. KEYDB media key + volume ID → VUK
|
||||
/// 3. MKB + processing keys → media key → VUK
|
||||
/// 4. MKB + device keys → processing key → media key → VUK
|
||||
fn resolve_keys_classical(ctx: &ResolveContext<'_>, version: AacsVersion) -> Option<ResolvedKeys> {
|
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let bus_encryption = ctx
|
||||
.content_cert
|
||||
.and_then(parse_content_cert)
|
||||
.map(|cc| cc.bus_encryption)
|
||||
.unwrap_or(false);
|
||||
|
||||
// Parse Unit_Key_RO.inf at the version-appropriate stride.
|
||||
let uk_file = parse_unit_key_ro(ctx.unit_key_ro, version)?;
|
||||
|
||||
let hash_hex = disc_hash_hex(&uk_file.disc_hash);
|
||||
|
||||
@@ -677,7 +830,7 @@ pub fn resolve_keys(
|
||||
vuk,
|
||||
unit_keys,
|
||||
title_cps_unit: uk_file.title_cps_unit.clone(),
|
||||
aacs2,
|
||||
version,
|
||||
bus_encryption,
|
||||
key_source,
|
||||
}
|
||||
@@ -686,15 +839,15 @@ pub fn resolve_keys(
|
||||
tracing::warn!(
|
||||
target: "freemkv::disc",
|
||||
phase = "resolve_keys_start",
|
||||
aacs2,
|
||||
version = ?version,
|
||||
bus_encryption,
|
||||
disc_hash = %hash_hex,
|
||||
mkb_present = mkb_data.is_some(),
|
||||
mkb_present = ctx.mkb.is_some(),
|
||||
"resolve_keys: starting"
|
||||
);
|
||||
|
||||
// Path 1: Look up VUK by disc hash in KEYDB
|
||||
if let Some(entry) = keydb.find_disc(&hash_hex) {
|
||||
if let Some(entry) = ctx.keydb.find_disc(&hash_hex) {
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path1_hit_entry", "disc hash found in keydb");
|
||||
if let Some(vuk) = entry.vuk {
|
||||
return Some(build(vuk, 1));
|
||||
@@ -710,7 +863,7 @@ pub fn resolve_keys(
|
||||
// sentinel "no VID" — short-circuit here so we don't surface a
|
||||
// misleading "all paths failed" log when really the math is
|
||||
// structurally impossible.
|
||||
if *volume_id == [0u8; 16] {
|
||||
if *ctx.volume_id == [0u8; 16] {
|
||||
tracing::warn!(
|
||||
target: "freemkv::disc",
|
||||
phase = "resolve_keys_no_vid",
|
||||
@@ -721,19 +874,19 @@ pub fn resolve_keys(
|
||||
|
||||
// Path 2: Find entry with matching VID → derive VUK from MK + VID
|
||||
let mut path2_mk_did_count = 0usize;
|
||||
for entry in keydb.disc_entries.values() {
|
||||
for entry in ctx.keydb.disc_entries.values() {
|
||||
if let (Some(mk), Some(did)) = (entry.media_key, entry.disc_id) {
|
||||
path2_mk_did_count += 1;
|
||||
if did == *volume_id {
|
||||
if did == *ctx.volume_id {
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_hit", "MK+VID entry matched volume_id");
|
||||
return Some(build(derive_vuk(&mk, volume_id), 2));
|
||||
return Some(build(derive_vuk(&mk, ctx.volume_id), 2));
|
||||
}
|
||||
}
|
||||
}
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_miss", mk_did_entries = path2_mk_did_count, "no MK+VID entry matched volume_id");
|
||||
|
||||
// Path 3: MKB + processing keys → media key → VUK
|
||||
if let Some(mkb) = mkb_data {
|
||||
if let Some(mkb) = ctx.mkb {
|
||||
let mk_dv = mkb_find_mk_dv(mkb);
|
||||
let subdiff = mkb_find_subdiff_records(mkb);
|
||||
let cvalues = mkb_find_cvalues(mkb);
|
||||
@@ -748,18 +901,18 @@ pub fn resolve_keys(
|
||||
"MKB record scan results"
|
||||
);
|
||||
|
||||
if let Some(mk) = derive_media_key_from_pk(mkb, &keydb.processing_keys) {
|
||||
if let Some(mk) = derive_media_key_from_pk(mkb, &ctx.keydb.processing_keys) {
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path3_hit", "media key derived from processing key");
|
||||
return Some(build(derive_vuk(&mk, volume_id), 3));
|
||||
return Some(build(derive_vuk(&mk, ctx.volume_id), 3));
|
||||
}
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path3_miss", pk_count = keydb.processing_keys.len(), "PK derivation failed");
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path3_miss", pk_count = ctx.keydb.processing_keys.len(), "PK derivation failed");
|
||||
|
||||
// Path 4: MKB + device keys → processing key → media key → VUK
|
||||
if let Some(mk) = derive_media_key_from_dk(mkb, &keydb.device_keys) {
|
||||
if let Some(mk) = derive_media_key_from_dk(mkb, &ctx.keydb.device_keys) {
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path4_hit", "media key derived from device key");
|
||||
return Some(build(derive_vuk(&mk, volume_id), 4));
|
||||
return Some(build(derive_vuk(&mk, ctx.volume_id), 4));
|
||||
}
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path4_miss", dk_count = keydb.device_keys.len(), "DK derivation failed");
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path4_miss", dk_count = ctx.keydb.device_keys.len(), "DK derivation failed");
|
||||
} else {
|
||||
tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_no_mkb", "no MKB data available; paths 3/4 skipped");
|
||||
}
|
||||
@@ -974,10 +1127,10 @@ mod tests {
|
||||
data[key2_pos + i] = 0xBB;
|
||||
}
|
||||
|
||||
let parsed = parse_unit_key_ro(&data, false).unwrap();
|
||||
let parsed = parse_unit_key_ro(&data, AacsVersion::V10).unwrap();
|
||||
assert_eq!(parsed.app_type, 1);
|
||||
assert_eq!(parsed.num_bdmv_dir, 1);
|
||||
assert!(!parsed.aacs2);
|
||||
assert_eq!(parsed.version, AacsVersion::V10);
|
||||
assert_eq!(parsed.encrypted_keys.len(), 2);
|
||||
assert_eq!(parsed.encrypted_keys[0].0, 1); // CPS unit 1
|
||||
assert_eq!(parsed.encrypted_keys[0].1, [0xAA; 16]);
|
||||
@@ -1197,7 +1350,14 @@ mod tests {
|
||||
);
|
||||
keydb.processing_keys.push([0u8; 16]);
|
||||
|
||||
let result = resolve_keys(&uk_ro, None, &zero_vid, &keydb, None);
|
||||
let ctx = ResolveContext {
|
||||
unit_key_ro: &uk_ro,
|
||||
content_cert: None,
|
||||
volume_id: &zero_vid,
|
||||
keydb: &keydb,
|
||||
mkb: None,
|
||||
};
|
||||
let result = resolve_keys_v1(&ctx);
|
||||
assert!(
|
||||
result.is_none(),
|
||||
"resolve_keys with VID=0 and no matching disc-hash entry must return None"
|
||||
@@ -1230,8 +1390,16 @@ mod tests {
|
||||
},
|
||||
);
|
||||
|
||||
let resolved = resolve_keys(&uk_ro, None, &[0u8; 16], &keydb, None)
|
||||
.expect("path 1 must run regardless of VID availability");
|
||||
let vid = [0u8; 16];
|
||||
let ctx = ResolveContext {
|
||||
unit_key_ro: &uk_ro,
|
||||
content_cert: None,
|
||||
volume_id: &vid,
|
||||
keydb: &keydb,
|
||||
mkb: None,
|
||||
};
|
||||
let resolved =
|
||||
resolve_keys_v1(&ctx).expect("path 1 must run regardless of VID availability");
|
||||
assert_eq!(resolved.vuk, known_vuk);
|
||||
assert_eq!(resolved.key_source, 1);
|
||||
}
|
||||
@@ -1243,14 +1411,14 @@ mod tests {
|
||||
data[0] = 0x00; // AACS 1.0
|
||||
data[1] = 0x00; // no bus encryption
|
||||
let cc = parse_content_cert(&data).unwrap();
|
||||
assert!(!cc.aacs2);
|
||||
assert_eq!(cc.version, AacsVersion::V10);
|
||||
assert!(!cc.bus_encryption);
|
||||
|
||||
// AACS 2.0 with bus encryption
|
||||
data[0] = 0x01; // AACS 2.0
|
||||
data[1] = 0x01; // bus encryption enabled
|
||||
let cc = parse_content_cert(&data).unwrap();
|
||||
assert!(cc.aacs2);
|
||||
assert_eq!(cc.version, AacsVersion::V20);
|
||||
assert!(cc.bus_encryption);
|
||||
}
|
||||
}
|
||||
|
||||
+10
-3
@@ -17,6 +17,7 @@ pub mod decrypt;
|
||||
pub mod handshake;
|
||||
pub mod keydb;
|
||||
pub mod keys;
|
||||
pub mod variants;
|
||||
|
||||
// Explicit re-exports — only items needed by external consumers and sibling crate modules.
|
||||
// AES primitives (aes_ecb_encrypt, aes_ecb_decrypt, aes_cbc_decrypt) are pub(crate) in decrypt.rs.
|
||||
@@ -26,7 +27,13 @@ pub use decrypt::{
|
||||
};
|
||||
pub use keydb::{DeviceKey, DiscEntry, HostCert, KeyDb};
|
||||
pub use keys::{
|
||||
ContentCert, ResolvedKeys, UnitKeyFile, decrypt_unit_key, derive_media_key_from_dk,
|
||||
derive_media_key_from_pk, derive_vuk, disc_hash, disc_hash_hex, mkb_version,
|
||||
parse_content_cert, parse_unit_key_ro, read_mkb_from_drive, resolve_keys,
|
||||
AacsVersion, ContentCert, ResolveContext, ResolvedKeys, UnitKeyFile, decrypt_unit_key,
|
||||
derive_media_key_from_dk, derive_media_key_from_pk, derive_vuk, disc_hash, disc_hash_hex,
|
||||
mkb_version, parse_content_cert, parse_unit_key_ro, read_mkb_from_drive, resolve_keys_v1,
|
||||
resolve_keys_v2, resolve_keys_v21,
|
||||
};
|
||||
pub use variants::{
|
||||
KEY_CORRECTION_DATA_PLACEHOLDER, MediaKeyVariantError, MkbRecord, ProcessingKeyMatch,
|
||||
derive_media_key_variant, is_variant_mkb, variant_data_record, variant_key_data, variant_nonce,
|
||||
walk_mkb, walk_processing_key,
|
||||
};
|
||||
|
||||
@@ -0,0 +1,679 @@
|
||||
//! AACS Media Key Variant chain.
|
||||
//!
|
||||
//! On AACS 2.1 the Media Key derivation gains a second stage on top of
|
||||
//! the classical subset-difference walk. The classical walk yields a
|
||||
//! Media Key Precursor (Kmp) rather than the final Media Key; the
|
||||
//! Precursor combines with disc-supplied Variant Key Data (VKD) and an
|
||||
//! integrator-supplied Key Correction Data (KCD) constant to produce
|
||||
//! the Media Key.
|
||||
//!
|
||||
//! This module is wiring only — `resolve_keys` is not aware of it. The
|
||||
//! entry point is [`derive_media_key_variant`]. The Variant scheme is
|
||||
//! detected via the new MKB record types `0x82` (Encrypted Media Key
|
||||
//! Variant Data + Variant Key Data) and `0x83` (Variant Number). When
|
||||
//! a disc carries neither, callers should fall back to the classical
|
||||
//! single-stage derivation in [`super::keys`].
|
||||
//!
|
||||
//! The chain follows the published spec:
|
||||
//!
|
||||
//! ```text
|
||||
//! Kmp = AES-128D(Kp, C) XOR uv
|
||||
//! Kpnew = Kmp XOR KCD
|
||||
//! Kvn = AES-G(Kp, Nonce) & 0xFFFF (low 16 bits, BE)
|
||||
//! VKD_idx = Kvn XOR VARIANTS[uv]
|
||||
//! VKD = vkd_table[VKD_idx * 16 .. +16]
|
||||
//! Km = AES-128D(Kpnew, VKD) XOR uv
|
||||
//! ```
|
||||
//!
|
||||
//! Two condition bits on `Kmp[15]` route off the hardcoded-KCD path
|
||||
//! (Soft Correction and Online Challenge). The chain refuses to run in
|
||||
//! either case — callers must handle those modes out of band.
|
||||
|
||||
use super::decrypt::aes_ecb_decrypt;
|
||||
use super::keydb::DeviceKey;
|
||||
|
||||
// ── Public constants ──────────────────────────────────────────────────────
|
||||
|
||||
/// Placeholder Key Correction Data. Sixteen zero bytes.
|
||||
///
|
||||
/// Integrators MUST supply a non-placeholder KCD via the `kcd` argument
|
||||
/// to [`derive_media_key_variant`]; the chain refuses to operate when
|
||||
/// the supplied KCD compares equal to this placeholder.
|
||||
pub const KEY_CORRECTION_DATA_PLACEHOLDER: [u8; 16] = [0u8; 16];
|
||||
|
||||
// ── MKB record walking ────────────────────────────────────────────────────
|
||||
|
||||
/// A single MKB record produced by [`walk_mkb`].
|
||||
#[derive(Debug, Clone)]
|
||||
pub struct MkbRecord {
|
||||
/// Byte offset of the record within the MKB.
|
||||
pub offset: usize,
|
||||
/// Record type byte.
|
||||
pub rec_type: u8,
|
||||
/// Record length in bytes (includes the 4-byte header).
|
||||
pub rec_len: usize,
|
||||
/// Record body (the bytes after the 4-byte header).
|
||||
pub body: Vec<u8>,
|
||||
}
|
||||
|
||||
/// Walk an MKB into a flat list of records.
|
||||
///
|
||||
/// MKB record framing per AACS: 1 byte type, 3 bytes BE length
|
||||
/// INCLUDING the 4-byte header, followed by payload. The walker stops
|
||||
/// at the first `(type=0, len=0)` end marker or at end of buffer.
|
||||
pub fn walk_mkb(mkb: &[u8]) -> Vec<MkbRecord> {
|
||||
let mut out = Vec::new();
|
||||
let mut pos = 0;
|
||||
while pos + 4 <= mkb.len() {
|
||||
let rec_type = mkb[pos];
|
||||
let rec_len = ((mkb[pos + 1] as usize) << 16)
|
||||
| ((mkb[pos + 2] as usize) << 8)
|
||||
| (mkb[pos + 3] as usize);
|
||||
if rec_type == 0 && rec_len == 0 {
|
||||
break;
|
||||
}
|
||||
if rec_len < 4 || pos + rec_len > mkb.len() {
|
||||
break;
|
||||
}
|
||||
let body = mkb[pos + 4..pos + rec_len].to_vec();
|
||||
out.push(MkbRecord {
|
||||
offset: pos,
|
||||
rec_type,
|
||||
rec_len,
|
||||
body,
|
||||
});
|
||||
pos += rec_len;
|
||||
}
|
||||
out
|
||||
}
|
||||
|
||||
/// True iff `records` contains at least one Media Key Variant record
|
||||
/// (type `0x82` or `0x83`).
|
||||
pub fn is_variant_mkb(records: &[MkbRecord]) -> bool {
|
||||
records.iter().any(|r| matches!(r.rec_type, 0x82 | 0x83))
|
||||
}
|
||||
|
||||
/// Body of the Encrypted Media Key Variant Data record (type `0x82`).
|
||||
pub fn variant_data_record(records: &[MkbRecord]) -> Option<&[u8]> {
|
||||
records
|
||||
.iter()
|
||||
.find(|r| r.rec_type == 0x82)
|
||||
.map(|r| r.body.as_slice())
|
||||
}
|
||||
|
||||
/// 16-byte Nonce from the Variant Number record (type `0x83`). Returns
|
||||
/// the first 16 bytes of the body.
|
||||
pub fn variant_nonce(records: &[MkbRecord]) -> Option<[u8; 16]> {
|
||||
let r = records.iter().find(|r| r.rec_type == 0x83)?;
|
||||
if r.body.len() < 16 {
|
||||
return None;
|
||||
}
|
||||
let mut out = [0u8; 16];
|
||||
out.copy_from_slice(&r.body[..16]);
|
||||
Some(out)
|
||||
}
|
||||
|
||||
/// Body of the Variant Key Data record. Returns the first `0x82` body
|
||||
/// that is a non-empty multiple of 16 bytes.
|
||||
pub fn variant_key_data(records: &[MkbRecord]) -> Option<&[u8]> {
|
||||
records
|
||||
.iter()
|
||||
.find(|r| r.rec_type == 0x82 && !r.body.is_empty() && r.body.len() % 16 == 0)
|
||||
.map(|r| r.body.as_slice())
|
||||
}
|
||||
|
||||
// ── AES-G ────────────────────────────────────────────────────────────────
|
||||
|
||||
/// AES-G(x1, x2) = AES-128D(x1, x2) XOR x2.
|
||||
///
|
||||
/// The Media Key Variant chain uses AES-G to derive both the variant
|
||||
/// number (`Kvn = AES-G(Kp, Nonce)`) and the Volume Unique Key
|
||||
/// (`Kvu = AES-G(Km, VID)`). See [`super::keys::derive_vuk`] for the
|
||||
/// classical VUK form — the math is identical, this exposes it as a
|
||||
/// neutral primitive for the variant chain.
|
||||
fn aes_g(x1: &[u8; 16], x2: &[u8; 16]) -> [u8; 16] {
|
||||
let mut out = aes_ecb_decrypt(x1, x2);
|
||||
for i in 0..16 {
|
||||
out[i] ^= x2[i];
|
||||
}
|
||||
out
|
||||
}
|
||||
|
||||
// ── Subset-difference walk that exposes (Kp, uv) ──────────────────────────
|
||||
|
||||
/// AES-G3 seed register initial value.
|
||||
const AESG3_SEED: [u8; 16] = [
|
||||
0x7B, 0x10, 0x3C, 0x5D, 0xCB, 0x08, 0xC4, 0xE5, 0x1A, 0x27, 0xB0, 0x17, 0x99, 0x05, 0x3B, 0xD9,
|
||||
];
|
||||
|
||||
/// AES-G3 single step: AES-G against the seed register at offset `inc`.
|
||||
fn aesg3_step(key: &[u8; 16], inc: u8) -> [u8; 16] {
|
||||
let mut seed = AESG3_SEED;
|
||||
seed[15] = seed[15].wrapping_add(inc);
|
||||
aes_g(key, &seed)
|
||||
}
|
||||
|
||||
fn calc_v_mask(uv: u32) -> u32 {
|
||||
let mut v_mask: u32 = 0xFFFF_FFFF;
|
||||
while (uv & !v_mask) == 0 && v_mask != 0 {
|
||||
v_mask <<= 1;
|
||||
}
|
||||
v_mask
|
||||
}
|
||||
|
||||
fn calc_pk_from_dk(dk: &[u8; 16], uv: u32, v_mask: u32, dev_key_v_mask: u32) -> [u8; 16] {
|
||||
let mut left_child = aesg3_step(dk, 0);
|
||||
let mut pk = aesg3_step(dk, 1);
|
||||
let mut right_child = aesg3_step(dk, 2);
|
||||
let mut current_v_mask = dev_key_v_mask;
|
||||
|
||||
while current_v_mask != v_mask {
|
||||
let mut bit_pos: i32 = -1;
|
||||
for i in (0..32).rev() {
|
||||
if (current_v_mask & (1u32 << i)) == 0 {
|
||||
bit_pos = i;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
let curr_key = if bit_pos < 0 || (uv & (1u32 << bit_pos as u32)) == 0 {
|
||||
left_child
|
||||
} else {
|
||||
right_child
|
||||
};
|
||||
|
||||
left_child = aesg3_step(&curr_key, 0);
|
||||
pk = aesg3_step(&curr_key, 1);
|
||||
right_child = aesg3_step(&curr_key, 2);
|
||||
|
||||
current_v_mask = ((current_v_mask as i32) >> 1) as u32;
|
||||
}
|
||||
|
||||
pk
|
||||
}
|
||||
|
||||
/// Outcome of a subset-difference walk against an MKB. Carries the
|
||||
/// processing key and the matching `uv` slot — both needed as inputs
|
||||
/// to the variant chain.
|
||||
#[derive(Debug, Clone, Copy)]
|
||||
pub struct ProcessingKeyMatch {
|
||||
/// Processing Key.
|
||||
pub kp: [u8; 16],
|
||||
/// Subset-difference node number that matched.
|
||||
pub uv: u32,
|
||||
/// 16-byte cvalue that the matched uv selected.
|
||||
pub cvalue: [u8; 16],
|
||||
/// Index of the matching cvalue within the cvalues record.
|
||||
pub cvalue_index: usize,
|
||||
}
|
||||
|
||||
fn mkb_find_body(records: &[MkbRecord], rec_type: u8) -> Option<&[u8]> {
|
||||
records
|
||||
.iter()
|
||||
.find(|r| r.rec_type == rec_type && !r.body.is_empty())
|
||||
.map(|r| r.body.as_slice())
|
||||
}
|
||||
|
||||
fn mkb_find_mk_dv(records: &[MkbRecord]) -> Option<[u8; 16]> {
|
||||
let r = records
|
||||
.iter()
|
||||
.find(|r| (r.rec_type == 0x81 || r.rec_type == 0x86) && r.body.len() >= 16)?;
|
||||
let mut out = [0u8; 16];
|
||||
out.copy_from_slice(&r.body[..16]);
|
||||
Some(out)
|
||||
}
|
||||
|
||||
/// Walk an MKB and return the first `(Kp, uv, cvalue)` that
|
||||
/// `device_keys` covers. Returns `None` if no DK walks any uv.
|
||||
pub fn walk_processing_key(
|
||||
records: &[MkbRecord],
|
||||
device_keys: &[DeviceKey],
|
||||
) -> Option<ProcessingKeyMatch> {
|
||||
let mk_dv = mkb_find_mk_dv(records)?;
|
||||
let uvs = mkb_find_body(records, 0x04)?;
|
||||
let cvalues = mkb_find_body(records, 0x07).or_else(|| mkb_find_body(records, 0x05))?;
|
||||
|
||||
let num_uvs = uvs
|
||||
.chunks(5)
|
||||
.take_while(|c| c.len() == 5 && (c[0] & 0xC0) == 0)
|
||||
.count();
|
||||
|
||||
for dk in device_keys {
|
||||
let device_number = dk.node as u32;
|
||||
|
||||
for uvs_idx in 0..num_uvs {
|
||||
let p_uv = &uvs[1 + 5 * uvs_idx..];
|
||||
let u_mask_shift = uvs[5 * uvs_idx];
|
||||
|
||||
if u_mask_shift & 0xC0 != 0 {
|
||||
break;
|
||||
}
|
||||
|
||||
let uv = u32::from_be_bytes([p_uv[0], p_uv[1], p_uv[2], p_uv[3]]);
|
||||
if uv == 0 {
|
||||
continue;
|
||||
}
|
||||
|
||||
let u_mask: u32 = 0xFFFF_FFFFu32.wrapping_shl(u_mask_shift as u32);
|
||||
let v_mask = calc_v_mask(uv);
|
||||
|
||||
if ((device_number & u_mask) == (uv & u_mask))
|
||||
&& ((device_number & v_mask) != (uv & v_mask))
|
||||
{
|
||||
let dev_key_v_mask = calc_v_mask(dk.uv);
|
||||
let dev_key_u_mask: u32 = 0xFFFF_FFFFu32.wrapping_shl(dk.u_mask_shift as u32);
|
||||
|
||||
if u_mask == dev_key_u_mask && (uv & dev_key_v_mask) == (dk.uv & dev_key_v_mask) {
|
||||
let pk = calc_pk_from_dk(&dk.key, uv, v_mask, dev_key_v_mask);
|
||||
|
||||
if uvs_idx >= cvalues.len() / 16 {
|
||||
continue;
|
||||
}
|
||||
let mut cv = [0u8; 16];
|
||||
cv.copy_from_slice(&cvalues[uvs_idx * 16..(uvs_idx + 1) * 16]);
|
||||
|
||||
// Validate: AES-D(Kp, cv), XOR uv into low 4 bytes,
|
||||
// then AES-D(.., mk_dv) must reveal the verify magic.
|
||||
let mut km_candidate = aes_ecb_decrypt(&pk, &cv);
|
||||
let uv_bytes = uv.to_be_bytes();
|
||||
for i in 0..4 {
|
||||
km_candidate[12 + i] ^= uv_bytes[i];
|
||||
}
|
||||
let dec_vd = aes_ecb_decrypt(&km_candidate, &mk_dv);
|
||||
const VERIFY_MAGIC: [u8; 8] = [0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF];
|
||||
// On a classical (non-variant) MKB this magic must
|
||||
// match. On a variant MKB it won't — `km_candidate`
|
||||
// is really Kmp and the magic check is moot. We
|
||||
// still gate the walk on cvalue indexing being
|
||||
// sane; the chain itself enforces the variant
|
||||
// semantics downstream.
|
||||
let classical_ok = dec_vd[..8] == VERIFY_MAGIC;
|
||||
let variant_present = is_variant_mkb(records);
|
||||
if !(classical_ok || variant_present) {
|
||||
continue;
|
||||
}
|
||||
|
||||
return Some(ProcessingKeyMatch {
|
||||
kp: pk,
|
||||
uv,
|
||||
cvalue: cv,
|
||||
cvalue_index: uvs_idx,
|
||||
});
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
None
|
||||
}
|
||||
|
||||
// ── Error reporting ───────────────────────────────────────────────────────
|
||||
|
||||
/// Outcome of [`derive_media_key_variant`] when the chain cannot
|
||||
/// produce a Media Key. Every variant is a classification only — no
|
||||
/// strings, no Display impl beyond the error code.
|
||||
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
|
||||
pub enum MediaKeyVariantError {
|
||||
/// MKB carries no Variant records. Caller should fall back to the
|
||||
/// classical single-stage derivation.
|
||||
NotVariantMkb,
|
||||
/// MKB is missing a required record (mk_dv, subset-difference,
|
||||
/// cvalues, variant data, or variant nonce).
|
||||
MkbIncomplete,
|
||||
/// `device_keys` did not cover any uv slot in this MKB.
|
||||
ProcessingKeyUnavailable,
|
||||
/// `Kmp[15]` carries bit `0x02`: the soft-correction path applies
|
||||
/// for this Precursor. Out of scope for the hardcoded-KCD chain.
|
||||
SoftCorrectionRequired,
|
||||
/// `Kmp[15]` carries bit `0x04`: the online-challenge path applies
|
||||
/// for this Precursor. Out of scope for the hardcoded-KCD chain.
|
||||
OnlineChallengeRequired,
|
||||
/// Supplied KCD equals [`KEY_CORRECTION_DATA_PLACEHOLDER`]. The
|
||||
/// derivation refuses to run with the all-zero placeholder.
|
||||
KcdNotProvided,
|
||||
/// `VARIANTS[uv]` lookup for the matched uv is not implemented.
|
||||
VariantsTableUnavailable,
|
||||
/// VKD index resolved out of the supplied `vkd_table`.
|
||||
VkdIndexOutOfRange,
|
||||
}
|
||||
|
||||
impl std::fmt::Display for MediaKeyVariantError {
|
||||
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
||||
let code: u16 = match self {
|
||||
MediaKeyVariantError::NotVariantMkb => 7100,
|
||||
MediaKeyVariantError::MkbIncomplete => 7101,
|
||||
MediaKeyVariantError::ProcessingKeyUnavailable => 7102,
|
||||
MediaKeyVariantError::SoftCorrectionRequired => 7103,
|
||||
MediaKeyVariantError::OnlineChallengeRequired => 7104,
|
||||
MediaKeyVariantError::KcdNotProvided => 7105,
|
||||
MediaKeyVariantError::VariantsTableUnavailable => 7106,
|
||||
MediaKeyVariantError::VkdIndexOutOfRange => 7107,
|
||||
};
|
||||
write!(f, "E{code}")
|
||||
}
|
||||
}
|
||||
|
||||
impl std::error::Error for MediaKeyVariantError {}
|
||||
|
||||
// ── Chain ─────────────────────────────────────────────────────────────────
|
||||
|
||||
/// Look up `VARIANTS[uv]` for the matched uv. The byte layout of the
|
||||
/// per-uv slot in the Variant Number record is undocumented and is
|
||||
/// disc-specific; this helper returns `None` until a Variant disc is
|
||||
/// available to fix the layout against.
|
||||
fn variants_for_uv(_records: &[MkbRecord], _uv_index: usize) -> Option<u16> {
|
||||
None
|
||||
}
|
||||
|
||||
/// Run the Media Key Variant chain on an MKB.
|
||||
///
|
||||
/// Inputs:
|
||||
///
|
||||
/// - `mkb_records` : MKB pre-walked via [`walk_mkb`].
|
||||
/// - `device_keys` : pool of device keys; the chain runs against the
|
||||
/// first uv slot any DK covers.
|
||||
/// - `kcd` : integrator-supplied Key Correction Data. Must not
|
||||
/// equal [`KEY_CORRECTION_DATA_PLACEHOLDER`].
|
||||
/// - `vid` : 16-byte Volume ID for the disc. Used to derive
|
||||
/// the final VUK alongside the Media Key.
|
||||
///
|
||||
/// Returns `(Km, Kvu)` on success.
|
||||
pub fn derive_media_key_variant(
|
||||
mkb_records: &[MkbRecord],
|
||||
device_keys: &[DeviceKey],
|
||||
kcd: &[u8; 16],
|
||||
vid: &[u8; 16],
|
||||
) -> Result<([u8; 16], [u8; 16]), MediaKeyVariantError> {
|
||||
if !is_variant_mkb(mkb_records) {
|
||||
return Err(MediaKeyVariantError::NotVariantMkb);
|
||||
}
|
||||
|
||||
let pkm = walk_processing_key(mkb_records, device_keys)
|
||||
.ok_or(MediaKeyVariantError::ProcessingKeyUnavailable)?;
|
||||
|
||||
let nonce = variant_nonce(mkb_records).ok_or(MediaKeyVariantError::MkbIncomplete)?;
|
||||
let vkd_table = variant_key_data(mkb_records).ok_or(MediaKeyVariantError::MkbIncomplete)?;
|
||||
let c_value = variant_data_record(mkb_records).ok_or(MediaKeyVariantError::MkbIncomplete)?;
|
||||
if c_value.len() < 16 {
|
||||
return Err(MediaKeyVariantError::MkbIncomplete);
|
||||
}
|
||||
let mut c_block = [0u8; 16];
|
||||
c_block.copy_from_slice(&c_value[..16]);
|
||||
|
||||
// Step: Kmp = AES-128D(Kp, C) XOR uv (uv into low 4 bytes).
|
||||
let mut kmp = aes_ecb_decrypt(&pkm.kp, &c_block);
|
||||
let uv_bytes = pkm.uv.to_be_bytes();
|
||||
for i in 0..4 {
|
||||
kmp[12 + i] ^= uv_bytes[i];
|
||||
}
|
||||
|
||||
// Condition bits on Kmp[15] route off the hardcoded-KCD path.
|
||||
if kmp[15] & 0b0000_0010 != 0 {
|
||||
return Err(MediaKeyVariantError::SoftCorrectionRequired);
|
||||
}
|
||||
if kmp[15] & 0b0000_0100 != 0 {
|
||||
return Err(MediaKeyVariantError::OnlineChallengeRequired);
|
||||
}
|
||||
if kcd == &KEY_CORRECTION_DATA_PLACEHOLDER {
|
||||
return Err(MediaKeyVariantError::KcdNotProvided);
|
||||
}
|
||||
|
||||
// Step: Kpnew = Kmp XOR KCD.
|
||||
let mut kpnew = [0u8; 16];
|
||||
for i in 0..16 {
|
||||
kpnew[i] = kmp[i] ^ kcd[i];
|
||||
}
|
||||
|
||||
// Step: Kvn = AES-G(Kp, Nonce) & 0xFFFF (low 16 bits, BE).
|
||||
let kvn_block = aes_g(&pkm.kp, &nonce);
|
||||
let kvn = u16::from_be_bytes([kvn_block[14], kvn_block[15]]);
|
||||
|
||||
// Step: VKD_idx = Kvn XOR VARIANTS[uv].
|
||||
let v_for_uv = variants_for_uv(mkb_records, pkm.cvalue_index)
|
||||
.ok_or(MediaKeyVariantError::VariantsTableUnavailable)?;
|
||||
let vkd_idx = kvn ^ v_for_uv;
|
||||
|
||||
// Step: VKD = vkd_table[VKD_idx * 16 .. +16].
|
||||
let off = (vkd_idx as usize) * 16;
|
||||
if off + 16 > vkd_table.len() {
|
||||
return Err(MediaKeyVariantError::VkdIndexOutOfRange);
|
||||
}
|
||||
let mut vkd = [0u8; 16];
|
||||
vkd.copy_from_slice(&vkd_table[off..off + 16]);
|
||||
|
||||
// Step: Km = AES-128D(Kpnew, VKD) XOR uv.
|
||||
let mut km = aes_ecb_decrypt(&kpnew, &vkd);
|
||||
for i in 0..4 {
|
||||
km[12 + i] ^= uv_bytes[i];
|
||||
}
|
||||
|
||||
// Step: Kvu = AES-G(Km, VID).
|
||||
let kvu = aes_g(&km, vid);
|
||||
|
||||
Ok((km, kvu))
|
||||
}
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
|
||||
// ── Helpers ──
|
||||
|
||||
fn synthetic_mkb_classical() -> Vec<u8> {
|
||||
// Minimal MKB: type/version record + cvalues + mk_dv. No variant
|
||||
// records.
|
||||
let mut mkb = vec![
|
||||
0x10, 0x00, 0x00, 0x0C, 0x48, 0x14, 0x10, 0x03, 0x00, 0x00, 0x00, 0x4D,
|
||||
];
|
||||
mkb.extend_from_slice(&[0x07, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&[0xAB; 16]);
|
||||
mkb.extend_from_slice(&[0x86, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&[0xCD; 16]);
|
||||
mkb
|
||||
}
|
||||
|
||||
fn synthetic_mkb_with_variant() -> Vec<u8> {
|
||||
let mut mkb = synthetic_mkb_classical();
|
||||
// 0x82 — 16-byte body (Variant data / VKD slot).
|
||||
mkb.extend_from_slice(&[0x82, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&[0xEE; 16]);
|
||||
// 0x83 — 16-byte body (Variant Nonce).
|
||||
mkb.extend_from_slice(&[0x83, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&[0x55; 16]);
|
||||
mkb
|
||||
}
|
||||
|
||||
// ── Walker / record detection ──
|
||||
|
||||
#[test]
|
||||
fn walker_parses_synthetic_mkb() {
|
||||
let mkb = synthetic_mkb_classical();
|
||||
let recs = walk_mkb(&mkb);
|
||||
assert_eq!(recs.len(), 3);
|
||||
assert_eq!(recs[0].rec_type, 0x10);
|
||||
assert_eq!(recs[1].rec_type, 0x07);
|
||||
assert_eq!(recs[2].rec_type, 0x86);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn variant_detection_negative_on_classical() {
|
||||
let recs = walk_mkb(&synthetic_mkb_classical());
|
||||
assert!(!is_variant_mkb(&recs));
|
||||
assert!(variant_nonce(&recs).is_none());
|
||||
assert!(variant_key_data(&recs).is_none());
|
||||
assert!(variant_data_record(&recs).is_none());
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn variant_detection_positive_on_variant() {
|
||||
let recs = walk_mkb(&synthetic_mkb_with_variant());
|
||||
assert!(is_variant_mkb(&recs));
|
||||
assert_eq!(variant_nonce(&recs), Some([0x55; 16]));
|
||||
assert_eq!(variant_key_data(&recs), Some(&[0xEE; 16][..]));
|
||||
assert_eq!(variant_data_record(&recs), Some(&[0xEE; 16][..]));
|
||||
}
|
||||
|
||||
// ── Chain entry-point classification ──
|
||||
|
||||
#[test]
|
||||
fn chain_rejects_non_variant_mkb() {
|
||||
let recs = walk_mkb(&synthetic_mkb_classical());
|
||||
let err = derive_media_key_variant(&recs, &[], &[0xAA; 16], &[0u8; 16])
|
||||
.expect_err("classical MKB must be rejected");
|
||||
assert_eq!(err, MediaKeyVariantError::NotVariantMkb);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn chain_rejects_placeholder_kcd() {
|
||||
// To reach the KCD check we need a complete variant MKB AND a
|
||||
// DK that walks it. We construct both via the synthetic
|
||||
// fixture below.
|
||||
let (recs, dk, _kp, _expected_kmp) = synthetic_variant_setup(/*kmp15*/ 0x00);
|
||||
let err =
|
||||
derive_media_key_variant(&recs, &[dk], &KEY_CORRECTION_DATA_PLACEHOLDER, &[0u8; 16])
|
||||
.expect_err("placeholder KCD must be rejected");
|
||||
assert_eq!(err, MediaKeyVariantError::KcdNotProvided);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn chain_detects_soft_correction_bit() {
|
||||
let (recs, dk, _, _) = synthetic_variant_setup(/*kmp15*/ 0x02);
|
||||
let err = derive_media_key_variant(&recs, &[dk], &[0xAA; 16], &[0u8; 16])
|
||||
.expect_err("bit 0x02 must surface SoftCorrectionRequired");
|
||||
assert_eq!(err, MediaKeyVariantError::SoftCorrectionRequired);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn chain_detects_online_challenge_bit() {
|
||||
let (recs, dk, _, _) = synthetic_variant_setup(/*kmp15*/ 0x04);
|
||||
let err = derive_media_key_variant(&recs, &[dk], &[0xAA; 16], &[0u8; 16])
|
||||
.expect_err("bit 0x04 must surface OnlineChallengeRequired");
|
||||
assert_eq!(err, MediaKeyVariantError::OnlineChallengeRequired);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn chain_surfaces_variants_table_gap_on_clean_kmp() {
|
||||
// With both condition bits clear and a non-placeholder KCD, the
|
||||
// chain advances to the per-uv VARIANTS[uv] lookup, which is
|
||||
// not yet wired. That returns VariantsTableUnavailable —
|
||||
// proving the bit checks and KCD check all passed.
|
||||
let (recs, dk, _, _) = synthetic_variant_setup(/*kmp15*/ 0x00);
|
||||
let err = derive_media_key_variant(&recs, &[dk], &[0xAA; 16], &[0u8; 16])
|
||||
.expect_err("expected VariantsTableUnavailable at the per-uv lookup");
|
||||
assert_eq!(err, MediaKeyVariantError::VariantsTableUnavailable);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn error_display_is_code_only() {
|
||||
// No English in Display — every variant emits "E7xxx" and
|
||||
// nothing else.
|
||||
let cases = [
|
||||
MediaKeyVariantError::NotVariantMkb,
|
||||
MediaKeyVariantError::MkbIncomplete,
|
||||
MediaKeyVariantError::ProcessingKeyUnavailable,
|
||||
MediaKeyVariantError::SoftCorrectionRequired,
|
||||
MediaKeyVariantError::OnlineChallengeRequired,
|
||||
MediaKeyVariantError::KcdNotProvided,
|
||||
MediaKeyVariantError::VariantsTableUnavailable,
|
||||
MediaKeyVariantError::VkdIndexOutOfRange,
|
||||
];
|
||||
for e in cases {
|
||||
let s = e.to_string();
|
||||
assert!(
|
||||
s.starts_with('E') && s.len() == 5,
|
||||
"error display must be E#### only, got {s:?}"
|
||||
);
|
||||
assert!(
|
||||
s.chars().skip(1).all(|c| c.is_ascii_digit()),
|
||||
"error display must be E + digits, got {s:?}"
|
||||
);
|
||||
}
|
||||
}
|
||||
|
||||
// ── Fixture construction ──
|
||||
|
||||
/// Build a synthetic variant MKB plus a DK that walks the single
|
||||
/// subset-difference slot it carries. `kmp15` is the value of the
|
||||
/// low byte of `Kmp[15]` that the chain will land on — pick `0x02`
|
||||
/// to exercise the SoftCorrection bit, `0x04` to exercise
|
||||
/// OnlineChallenge, `0x00` otherwise.
|
||||
///
|
||||
/// The fixture pins:
|
||||
/// - MKB subset-difference: `u_mask_shift=3, uv=2`. With these
|
||||
/// masks the discriminator bit (u_mask=1, v_mask=0) is bit 2.
|
||||
/// - one DK at `node=4, uv=2, u_mask_shift=3`. node 4 has bit 2 set
|
||||
/// (differs from uv=2 on bit 2 → disagrees on v_mask) while
|
||||
/// agreeing with uv on bits 3+ (the u_mask=1 region). dk.uv ==
|
||||
/// MKB.uv and dk.u_mask_shift == MKB.u_mask_shift make
|
||||
/// `dev_key_v_mask == v_mask`, so `calc_pk_from_dk` loops zero
|
||||
/// times — Kp = aesg3_step(dk, 1).
|
||||
/// - one cvalue in record 0x07 chosen so AES-D(Kp, C) ⊕ uv produces a
|
||||
/// Kmp whose byte-15 is exactly `kmp15`.
|
||||
/// - record 0x82 with a 16-byte body (acts as both Variant Data
|
||||
/// and Variant Key Data; satisfies the parser heuristics).
|
||||
/// - record 0x83 with a 16-byte Nonce.
|
||||
///
|
||||
/// Returns (records, dk, planted_kp, planted_kmp).
|
||||
fn synthetic_variant_setup(kmp15: u8) -> (Vec<MkbRecord>, DeviceKey, [u8; 16], [u8; 16]) {
|
||||
use crate::aacs::decrypt::aes_ecb_encrypt;
|
||||
|
||||
// Build header.
|
||||
let mut mkb = vec![
|
||||
0x10, 0x00, 0x00, 0x0C, 0x48, 0x14, 0x10, 0x03, 0x00, 0x00, 0x00, 0x4D,
|
||||
];
|
||||
|
||||
// Subset-difference (0x04): u_mask_shift=3, uv=00 00 00 02.
|
||||
mkb.extend_from_slice(&[0x04, 0x00, 0x00, 0x09]);
|
||||
mkb.extend_from_slice(&[0x03, 0x00, 0x00, 0x00, 0x02]);
|
||||
|
||||
// Pick a known DK; with dk.uv == MKB.uv (==2) and
|
||||
// dk.u_mask_shift == MKB.u_mask_shift (==1), dev_key_v_mask
|
||||
// equals the MKB's v_mask and the calc_pk_from_dk loop is a
|
||||
// no-op — Kp = aesg3_step(dk, 1).
|
||||
let dk_bytes: [u8; 16] = [
|
||||
0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE,
|
||||
0xFF, 0x00,
|
||||
];
|
||||
let kp = aesg3_step(&dk_bytes, 1);
|
||||
|
||||
// Plant Kmp with chosen byte-15, then compute C such that
|
||||
// AES-D(Kp, C) ⊕ uv == Kmp. uv=2 → low-4 bytes XOR is 00 00 00 02.
|
||||
let mut kmp = [0x42u8; 16];
|
||||
kmp[15] = kmp15;
|
||||
let mut aes_d_result = kmp;
|
||||
aes_d_result[15] ^= 0x02;
|
||||
let c_block = aes_ecb_encrypt(&kp, &aes_d_result);
|
||||
|
||||
// cvalues record (0x07): one 16-byte cvalue. The walker
|
||||
// indexes it for the magic-check step; on a variant MKB the
|
||||
// magic check fails but `variant_present` is true so the
|
||||
// walker still returns the match. Content is don't-care.
|
||||
mkb.extend_from_slice(&[0x07, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&[0xAB; 16]);
|
||||
|
||||
// Verify Media Key (0x86): body content is don't-care.
|
||||
mkb.extend_from_slice(&[0x86, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&[0xCD; 16]);
|
||||
|
||||
// 0x82 record: holds C (Encrypted Media Key Variant Data) AND
|
||||
// doubles as the VKD table (single 16-byte entry → VKDidx must
|
||||
// resolve to 0 for `chain_surfaces_variants_table_gap` test —
|
||||
// but the test never reaches the VKD lookup since the
|
||||
// VARIANTS[uv] helper is not yet wired).
|
||||
mkb.extend_from_slice(&[0x82, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&c_block);
|
||||
|
||||
// 0x83 record: 16-byte Nonce.
|
||||
mkb.extend_from_slice(&[0x83, 0x00, 0x00, 0x14]);
|
||||
mkb.extend_from_slice(&[0x77; 16]);
|
||||
|
||||
let recs = walk_mkb(&mkb);
|
||||
|
||||
let dk = DeviceKey {
|
||||
key: dk_bytes,
|
||||
node: 4,
|
||||
uv: 2,
|
||||
u_mask_shift: 3,
|
||||
};
|
||||
(recs, dk, kp, kmp)
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user