Fix rc5 audit findings: keydb doc, pipeline ordering, hot-loop Arc, tests

- keydb.rs: separate default_path()/no_home_dir() doc blocks; correct the
  false XDG lock-step claim (Linux write path uses $HOME, ignores
  XDG_CONFIG_HOME; read-side search also checks XDG_CONFIG_HOME).
- io/pipeline.rs: use Release/Acquire on the abandoned flag so a leaked
  consumer reliably skips close() on weak memory models (ARM64/POWER),
  not just x86 TSO.
- mux/disc.rs: cache the decrypt-loss Arc at construction; lost_bytes()
  no longer clones an Arc per frame on the mux hot path.
- disc/dvd.rs: assert display_aspect mapping for both 16:9 (PAL test) and
  4:3 (NTSC test).
- mux/resolve.rs: extract css_error_aborts() helper and unit-test the
  scrambled-but-uncracked CSS guard (Fix 6) incl. the --raw exemption.
- aacs/keys.rs: add unit tests for mkb_type_raw/mkb_type/mkb_is_uhd and
  MkbType (Category C 2.0 UHD, prerecorded 1.0, no-0x10-record None).
- release.yml: publish job needs [verify, test] so a failing test suite
  blocks crates.io publication.

src/aacs/keys.rs

@@ -2650,6 +2650,46 @@ mod tests {
         assert_eq!(mkb_version(&mkb), Some(0x0102_0304));
     }
 
+    #[test]
+    fn mkb_type_category_c_20_is_uhd() {
+        // Type 0x10 record, BE24 length 0x0C (12). MKBType field (body
+        // offset 0 = pos+4) = MKB_20_CATEGORY_C (0x48141003).
+        let mkb = [
+            0x10, 0x00, 0x00, 0x0C, 0x48, 0x14, 0x10, 0x03, 0x00, 0x00, 0x00, 0x01,
+        ];
+        assert_eq!(mkb_type_raw(&mkb), Some(MKB_20_CATEGORY_C));
+        assert_eq!(mkb_type(&mkb), Some(MkbType::CategoryC20));
+        assert_eq!(mkb_is_uhd(&mkb), Some(true));
+        assert!(MkbType::CategoryC20.is_uhd());
+        assert_eq!(MkbType::CategoryC20.generation(), AacsVersion::V20);
+        // Sanity on the 2.1 sibling.
+        assert_eq!(MkbType::from_raw(MKB_21_CATEGORY_C), MkbType::CategoryC21);
+        assert_eq!(MkbType::CategoryC21.generation(), AacsVersion::V21);
+    }
+
+    #[test]
+    fn mkb_type_prerecorded_is_bluray_v10() {
+        // Type 0x10 record with MKB_TYPE_4_PRERECORDED (0x00041003) — a
+        // standard Blu-ray (AACS 1.0) block, not UHD.
+        let mkb = [
+            0x10, 0x00, 0x00, 0x0C, 0x00, 0x04, 0x10, 0x03, 0x00, 0x00, 0x00, 0x01,
+        ];
+        assert_eq!(mkb_type(&mkb), Some(MkbType::Prerecorded));
+        assert_eq!(mkb_is_uhd(&mkb), Some(false));
+        assert!(!MkbType::Prerecorded.is_uhd());
+        assert_eq!(MkbType::Prerecorded.generation(), AacsVersion::V10);
+    }
+
+    #[test]
+    fn mkb_type_none_when_no_0x10_record() {
+        // A buffer whose only record is a 0x81 (verify-media-key) record and
+        // no 0x10 Type-and-Version record → mkb_type_raw returns None.
+        let mkb = [0x81, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00];
+        assert_eq!(mkb_type_raw(&mkb), None);
+        assert_eq!(mkb_type(&mkb), None);
+        assert_eq!(mkb_is_uhd(&mkb), None);
+    }
+
     #[test]
     fn mkb_find_mk_dv_skips_short_verify_record() {
         // A 0x81 record with rec_len < 20 carries no full mk_dv; the finder

src/disc/dvd.rs

@@ -542,7 +542,7 @@ mod tests {
         let vmg = build_vmg(&[(1, 1, 1)]);
         let vts = build_vts(
             0,
-            crate::ifo::v_atr_byte(crate::ifo::VIDEO_FORMAT_PAL, crate::ifo::ASPECT_4X3),
+            crate::ifo::v_atr_byte(crate::ifo::VIDEO_FORMAT_PAL, crate::ifo::ASPECT_16X9),
             &[],
             &[],
             &[(0, 9)],
@@ -582,6 +582,11 @@ mod tests {
             ColorSpace::Bt470bg,
             "PAL DVD is SD BT.470BG, not BT.709"
         );
+        assert_eq!(
+            v.display_aspect,
+            Some((16, 9)),
+            "ASPECT_16X9 IFO byte must map to a 16:9 display aspect"
+        );
     }
 
     /// NTSC DVD video is SD SMPTE-170M colorimetry (not BT.709). Mirror of the
@@ -631,6 +636,11 @@ mod tests {
             ColorSpace::Smpte170m,
             "NTSC DVD is SD SMPTE-170M, not BT.709"
         );
+        assert_eq!(
+            v.display_aspect,
+            Some((4, 3)),
+            "ASPECT_4X3 IFO byte must map to a 4:3 display aspect"
+        );
     }
 
     /// AC-3 audio gets sub_stream_id 0x80 → PID routed via dvd_audio_pid

src/io/pipeline.rs

@@ -150,7 +150,11 @@ fn finish_with_grace<R: Send + 'static>(
     // observes it the moment its wedged syscall returns: it then skips
     // any further `apply` and skips `close()`, rather than running on to
     // finalise the abandoned output file.
-    abandoned.store(true, Ordering::Relaxed);
+    // `Release` here pairs with the `Acquire` loads in the consumer loop so
+    // the leaked consumer reliably observes the flag the moment its wedged
+    // syscall returns, even on weak memory models (ARM64/POWER) where
+    // `Relaxed` gives no cross-thread visibility guarantee.
+    abandoned.store(true, Ordering::Release);
     tracing::warn!(
         target: "freemkv::pipeline",
         phase = "finish_with_halt_grace_expired",
@@ -299,7 +303,7 @@ impl<I: Send + 'static, R: Send + 'static> Pipeline<I, R> {
                     // dead receiver, but we touch the output no further. The
                     // final post-loop abandonment check returns the error
                     // and skips `close()`.
-                    if abandoned_consumer.load(Ordering::Relaxed) {
+                    if abandoned_consumer.load(Ordering::Acquire) {
                         continue;
                     }
 
@@ -359,7 +363,7 @@ impl<I: Send + 'static, R: Send + 'static> Pipeline<I, R> {
                 // MKV Cues + patching the segment header) on a file the
                 // caller already reported as failed is exactly the
                 // write race we must not run.
-                if abandoned_consumer.load(Ordering::Relaxed) {
+                if abandoned_consumer.load(Ordering::Acquire) {
                     return Err(Error::Halted);
                 }
 

src/keydb.rs

@@ -43,17 +43,6 @@ fn read_capped_to_string<R: Read>(reader: R) -> Result<String> {
     String::from_utf8(buf).map_err(|_| Error::KeydbParse)
 }
 
-/// Standard keydb storage path — the canonical location to write the keydb to.
-///
-/// On Windows this is the idiomatic per-user roaming dir
-/// `%APPDATA%\freemkv\keydb.cfg`, falling back to the legacy
-/// `%USERPROFILE%\.config\freemkv\keydb.cfg` only if `APPDATA` is unset. On
-/// Linux/macOS it stays the long-standing `$HOME/.config/freemkv/keydb.cfg`.
-///
-/// The CLI's read-side search (first existing of several locations) lives in
-/// `freemkv-keysources::keydb_search_paths`; this function is the single
-/// *write* default used by `save`/`update`, kept in lock-step with that crate's
-/// `default_keydb_path` for the same OS.
 /// Build the error returned when no home directory can be determined
 /// (`HOME`/`USERPROFILE` unset). This is an *environment* failure — the
 /// process has no home dir, which typically signals a stripped container
@@ -66,6 +55,23 @@ fn no_home_dir() -> Error {
     }
 }
 
+/// Standard keydb storage path — the canonical location to write the keydb to.
+///
+/// On Windows this is the idiomatic per-user roaming dir
+/// `%APPDATA%\freemkv\keydb.cfg`, falling back to the legacy
+/// `%USERPROFILE%\.config\freemkv\keydb.cfg` only if `APPDATA` is unset. On
+/// Linux/macOS it stays the long-standing `$HOME/.config/freemkv/keydb.cfg`.
+///
+/// The CLI's read-side search (first existing of several locations) lives in
+/// `freemkv-keysources::keydb_search_paths`; this function is the single
+/// *write* default used by `save`/`update`. On Windows the two agree. On
+/// Linux they can diverge: this write path always uses
+/// `$HOME/.config/freemkv/keydb.cfg` and ignores `XDG_CONFIG_HOME`, whereas
+/// the read-side search additionally checks `$XDG_CONFIG_HOME/freemkv` first.
+/// A user who sets `XDG_CONFIG_HOME` to a non-`$HOME/.config` location will
+/// therefore have `update-keys` write to the `$HOME` path while the read-side
+/// search may prefer the `XDG_CONFIG_HOME` location — the `$HOME` path is still
+/// in the search list, so the freshly-written keydb is found, just not first.
 pub fn default_path() -> Result<PathBuf> {
     #[cfg(windows)]
     {

src/mux/disc.rs

@@ -108,6 +108,11 @@ pub struct DiscStream {
     /// inline `decrypt::decrypt_sectors` step. `DecryptKeys::None`
     /// (raw / unencrypted disc) makes the decorator a pass-through.
     reader: DecryptingSectorSource<Box<dyn SectorSource>>,
+    /// Shared decrypt-loss counter, cloned once at construction from
+    /// `reader.decrypt_loss()`. `lost_bytes()` loads it directly so the
+    /// per-frame hot path performs no per-call `Arc::clone` (matching the
+    /// `PipelinedPesStream` pattern).
+    decrypt_loss: std::sync::Arc<std::sync::atomic::AtomicU64>,
     title: DiscTitle,
     /// Mirror of the keys handed in at construction. The decorator
     /// owns the cryptographic state; this field is kept for
@@ -253,12 +258,17 @@ impl DiscStream {
             _ => 1,
         };
 
+        // Wrap the input reader in DecryptingSectorSource so the internal
+        // fill_extents path sees plaintext bytes. For DecryptKeys::None
+        // (unencrypted / raw / test fixtures) the decorator is a pass-through.
+        let reader = DecryptingSectorSource::new(reader, decrypt_keys.clone());
+        // Clone the shared loss counter once here so `lost_bytes()` never
+        // clones an Arc per frame on the mux hot path.
+        let decrypt_loss = reader.decrypt_loss();
+
         Self {
-            // Wrap the input reader in DecryptingSectorSource so the
-            // internal fill_extents path sees plaintext bytes. For
-            // DecryptKeys::None (unencrypted / raw / test fixtures)
-            // the decorator is a pass-through.
-            reader: DecryptingSectorSource::new(reader, decrypt_keys.clone()),
+            reader,
+            decrypt_loss,
             title,
             decrypt_keys,
             unit_align,
@@ -802,11 +812,8 @@ impl crate::pes::Stream for DiscStream {
         // them). Both are real missing content the abort gate must see; without
         // the decrypt term a partial key failure reports lost_bytes=0 and a rip
         // missing segments passes even under abort_on_lost_secs=0.
-        self.lost_bytes.saturating_add(
-            self.reader
-                .decrypt_loss()
-                .load(std::sync::atomic::Ordering::Relaxed),
-        )
+        self.lost_bytes
+            .saturating_add(self.decrypt_loss.load(std::sync::atomic::Ordering::Relaxed))
     }
 }
 

src/mux/resolve.rs

@@ -249,6 +249,17 @@ fn css_key_missing(raw: bool, has_css: bool, keys: &crate::decrypt::DecryptKeys)
     !raw && has_css && matches!(keys, crate::decrypt::DecryptKeys::None)
 }
 
+/// Scrambled-but-uncracked CSS guard (Fix 6). Returns `true` when decryption
+/// is requested (`!raw`) and the scan recorded a hard CSS error
+/// (`has_css_error` — `disc.css_error.is_some()`), meaning the content is
+/// scrambled but no title key was recovered (so `disc.css` is `None`). Muxing
+/// that case would pass scrambled MPEG through as plaintext, so the caller
+/// fails fast with [`Error::CssKeyMissing`]. `--raw` is exempt (skips
+/// decryption), so it always returns `false`.
+fn css_error_aborts(raw: bool, has_css_error: bool) -> bool {
+    !raw && has_css_error
+}
+
 /// Open a PES input stream (produces PES frames).
 pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::Stream>> {
     let parsed = parse_url(url);
@@ -290,7 +301,7 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
             // as "unencrypted" and the scrambled MPEG would mux as plaintext
             // garbage at exit 0. Surface the recorded hard error instead.
             // `--raw` skips decryption, so it is exempt.
-            if !opts.raw && disc.css_error.is_some() {
+            if css_error_aborts(opts.raw, disc.css_error.is_some()) {
                 return Err(crate::error::Error::CssKeyMissing.into());
             }
             // No-key guard: if decryption is requested (not --raw) and the disc
@@ -658,6 +669,7 @@ fn build_m2ts_pipeline<R: std::io::Read + Send + 'static>(
 mod tests {
     use super::StreamUrl;
     use super::aacs_key_missing;
+    use super::css_error_aborts;
     use super::css_key_missing;
     use super::parse_url;
     use super::validate_network_addr;
@@ -779,6 +791,18 @@ mod tests {
         assert!(!css_key_missing(false, false, &DecryptKeys::None));
     }
 
+    #[test]
+    fn css_error_field_aborts_unless_raw() {
+        // Fix 6: a scrambled-but-uncracked DVD records a hard error in
+        // `disc.css_error` (css is None). With decryption requested the
+        // input() guard must abort with CssKeyMissing.
+        assert!(css_error_aborts(false, true));
+        // --raw skips decryption → never aborts on the css_error field.
+        assert!(!css_error_aborts(true, true));
+        // No recorded css_error → the guard does not fire.
+        assert!(!css_error_aborts(false, false));
+    }
+
     #[test]
     fn raw_never_aborts() {
         // --raw skips decryption — must never hit the no-key abort, even on an