fix: Fix an issue where the central directory could be incorrectly detected

src/read.rs

@@ -442,7 +442,7 @@ impl<R: Read + Seek> ZipArchive<R> {
             )?;
             /* This is only ever used internally to cache metadata lookups (it's not part of the
              * zip spec), and 0 is the sentinel value. */
-            f.central_header_start = 0;
+            // f.central_header_start = 0;
             /* This is an atomic variable so it can be updated from another thread in the
              * implementation (which is good!). */
             if let Some(old_data_start) = f.data_start.take() {
@@ -727,7 +727,7 @@ impl<R: Read + Seek> ZipArchive<R> {
         }
         let shared = ok_results
             .into_iter()
-            .max_by_key(|shared| shared.dir_start)
+            .max_by_key(|shared| shared.dir_start - shared.offset)
             .unwrap();
         reader.seek(io::SeekFrom::Start(shared.dir_start))?;
         Ok(shared)

src/write.rs

@@ -2495,4 +2495,44 @@ mod test {
         let _ = ZipArchive::new(first_writer.finish()?)?;
         Ok(())
     }
+
+    #[cfg(feature = "bzip2")]
+    #[test]
+    fn test_fuzz_failure_2024_06_08() -> ZipResult<()> {
+        use crate::write::ExtendedFileOptions;
+        use CompressionMethod::Bzip2;
+
+        let mut writer = ZipWriter::new(Cursor::new(Vec::new()));
+        writer.set_flush_on_finish_file(false);
+        const SYMLINK_PATH: &'static str = "PK\u{6}\u{6}K\u{6}\u{6}\u{6}\0\0\0\0\u{18}\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\u{1}\0\0\0\0\0\0\0\0\u{1}\0\0PK\u{1}\u{2},\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\u{1}\0\0PK\u{1}\u{2},\0\0\0\0\0\0\0\0\0\0l\0\0\0\0\0\0PK\u{6}\u{7}P\0\0\0\0\0\0\0\0\0\0\0\0\u{1}\0\0";
+        let sub_writer = {
+            let mut writer = ZipWriter::new(Cursor::new(Vec::new()));
+            writer.set_flush_on_finish_file(false);
+            let options = FileOptions {
+                compression_method: Bzip2,
+                compression_level: None,
+                last_modified_time: DateTime::from_date_and_time(1980, 5, 20, 21, 0, 57)?,
+                permissions: None,
+                large_file: false,
+                encrypt_with: None,
+                extended_options: ExtendedFileOptions {
+                    extra_data: vec![].into(),
+                    central_extra_data: vec![].into(),
+                },
+                alignment: 2048,
+                zopfli_buffer_size: None,
+            };
+            writer.add_symlink_from_path(SYMLINK_PATH, "||\0\0\0\0", options)?;
+            writer = ZipWriter::new_append(writer.finish_into_readable()?.into_inner())?;
+            writer.deep_copy_file_from_path(SYMLINK_PATH, "")?;
+            writer = ZipWriter::new_append(writer.finish_into_readable()?.into_inner())?;
+            writer.abort_file()?;
+            writer
+        };
+        writer.merge_archive(sub_writer.finish_into_readable()?)?;
+        writer = ZipWriter::new_append(writer.finish_into_readable()?.into_inner())?;
+        writer.deep_copy_file_from_path(SYMLINK_PATH, "foo")?;
+        let _ = writer.finish_into_readable()?;
+        Ok(())
+    }
 }