File modes for DOS archives not correctly mapped to unix modes

[JellyWX]

Describe the bug

9e9badde appears to have broken permissions on extracted DOS zips. I noticed this when trying to extract Bandcamp downloads (not attached due to copyright note) on COSMIC, which is compiled against zip 7.2.0

I'm still investigating a bit, but seems to be related to #471, #470

The COSMIC issue pop-os/cosmic-epoch#2525 looks related, but pre-dates this.

To Reproduce

Take this file: unix_mode_0x081A4000.zip

Calling unix_mode() against the file in this zip returns 2074. Prior to the linked commit, this would return 33204.

use std::io::Cursor;
use zip::ZipArchive;

#[test]
fn unix_mode_dos() {
    let data = include_bytes!("data/unix_mode_0x081A4000.zip");
    let mut archive = ZipArchive::new(Cursor::new(data)).unwrap();
    for i in 0..archive.len() {
        let file = archive.by_index(i).unwrap();
        assert_eq!(
            file.unix_mode(),
            Some(33204),
            "file {:?} has unix_mode {:?}",
            file.name(),
            file.unix_mode()
        );
    }
}

The result in COSMIC is files with permission set as ---S-wx-w-

jude@xxx:~/Downloads/unix_mode_0x081A4000$ ls -lah
total 12K
drwxrwxr-x 2 jude jude 4.0K Mar 20 09:12 .
drwxr-xr-x 8 jude jude 4.0K Mar 20 09:12 ..
---S-wx-w- 1 jude jude   11 Jan  1  1980 test_file.txt

Desktop

• OS: Pop!_OS 24.04

I've also tested this with the latest version of the library. The commit above was picked out with a bisection. I've confirmed that compiling COSMIC files with zip=7.1.0 resolves this issue

[JellyWX]

Occurs to me that possibly Bandcamp are also using an older version of this package or something, which could cause issues. I think the main benchmark though is that the linux unzip command handles these files correctly