If the iloc size is corrupt, return an Err rather than asserting

See https://bugzilla.mozilla.org/show_bug.cgi?id=1655846

Author: baumanj

mp4parse/src/lib.rs

@@ -1603,9 +1603,11 @@ fn read_iloc<T: Read>(src: &mut BMFFBox<T>) -> Result<TryVec<ItemLocationBoxItem
         })?;
     }
 
-    debug_assert_eq!(iloc.remaining(), 0);
-
-    Ok(items)
+    if iloc.remaining() == 0 {
+        Ok(items)
+    } else {
+        Err(Error::InvalidData("invalid iloc size"))
+    }
 }
 
 /// Read the contents of a box, including sub boxes.

mp4parse/tests/bug-1655846.avif

@@ -28,6 +28,7 @@ static AUDIO_EME_CBCS_MP4: &str = "tests/bipbop_cbcs_audio_init.mp4";
 static VIDEO_EME_CBCS_MP4: &str = "tests/bipbop_cbcs_video_init.mp4";
 static VIDEO_AV1_MP4: &str = "tests/tiny_av1.mp4";
 static IMAGE_AVIF: &str = "av1-avif/testFiles/Microsoft/Monochrome.avif";
+static IMAGE_AVIF_CORRUPT: &str = "tests/bug-1655846.avif";
 static IMAGE_AVIF_GRID: &str = "av1-avif/testFiles/Microsoft/Summer_in_Tomsk_720p_5x4_grid.avif";
 static AVIF_TEST_DIR: &str = "av1-avif/testFiles";
 
@@ -627,6 +628,13 @@ fn public_avif_primary_item() {
     assert_eq!(context.primary_item[0..4], [0x12, 0x00, 0x0a, 0x0a]);
 }
 
+#[test]
+fn public_avif_bug_1655846() {
+    let context = &mut mp4::AvifContext::new();
+    let input = &mut File::open(IMAGE_AVIF_CORRUPT).expect("Unknown file");
+    assert!(mp4::read_avif(input, context).is_err());
+}
+
 #[test]
 #[ignore] // Remove when we add support; see https://github.com/mozilla/mp4parse-rust/issues/198
 fn public_avif_primary_item_is_grid() {