Merge pull request #345 from mozilla/hdlr-name-multiple-nul

Check for multiple nul bytes in `hdlr` box `name` field

Author: baumanj

mp4parse/src/lib.rs

@@ -4514,12 +4514,23 @@ fn read_hdlr<T: Read>(src: &mut BMFFBox<T>, strictness: ParseStrictness) -> Resu
 
     match std::str::from_utf8(src.read_into_try_vec()?.as_slice()) {
         Ok(name) => {
-            if name.bytes().last() != Some(b'\0') {
-                fail_if(
+            match name.bytes().filter(|&b| b == b'\0').count() {
+                0 => fail_if(
                     strictness != ParseStrictness::Permissive,
                     "The HandlerBox 'name' field shall be null-terminated \
                      per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2",
-                )?
+                )?,
+                1 => (),
+                _ =>
+                // See https://github.com/MPEGGroup/FileFormat/issues/35
+                {
+                    fail_if(
+                        strictness == ParseStrictness::Strict,
+                        "The HandlerBox 'name' field shall have a NUL byte \
+                         only in the final position \
+                         per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2",
+                    )?
+                }
             }
         }
         Err(_) => fail_if(

mp4parse/src/tests.rs

@@ -475,6 +475,24 @@ fn read_hdlr() {
     assert_eq!(parsed.handler_type, b"vide");
 }
 
+#[test]
+fn read_hdlr_multiple_nul_in_name() {
+    let mut stream = make_fullbox(BoxSize::Short(45), b"hdlr", 0, |s| {
+        s.B32(0)
+            .append_bytes(b"vide")
+            .B32(0)
+            .B32(0)
+            .B32(0)
+            .append_bytes(b"Vide\0Handler")
+            .B8(0) // null-terminate string
+    });
+    let mut iter = super::BoxIter::new(&mut stream);
+    let mut stream = iter.next_box().unwrap().unwrap();
+    assert_eq!(stream.head.name, BoxType::HandlerBox);
+    assert_eq!(stream.head.size, 45);
+    assert!(super::read_hdlr(&mut stream, ParseStrictness::Strict).is_err());
+}
+
 #[test]
 fn read_hdlr_short_name() {
     let mut stream = make_fullbox(BoxSize::Short(33), b"hdlr", 0, |s| {