iso9660 file isn't a supported "archive" type in Files.app, i.e. cros-disks doesn't service a request to mount a .iso file in Downloads folder

The current iso9660 support is for mounting a CD/DVD on an external CD/DVD drive as a filesystem.

gotcha, so WGU is already the way to mount an ISO image in the Files app.  we still have the same attack surface, but it's a little bit harder (burn the malformed image, then plug it in via USB).

replumbing the raw device node to chronos/Files app is probably not an improvement (due to ioctl exposure).

so is the best we can do here is move to a fuse implementation like archivemount ?
  http://www.cybernoia.de/software/archivemount/
it uses libarchive to parse iso9660 images.

Is this issue still valid? We need iso9660 kernel support for physical CD disks (not images). I can't see a good way (I can see bad ways) or reason to remove it.

it's still valid in the sense that we're exposing the kernel directly to removable media which is bad for security.  we shouldn't have a system where inserting a CD-ROM into a USB drive can result in immediate & full system exploit.  i'm not saying there are any such known bugs today, but if there were, we have 0 layers of defense here.

We do this for FAT32, ext2/3/4, UDF, and HFS+. Is iso9660 any different from those?

every user that hits the kernel directly is a problem. we should have a bug per filesystem to migrate them as needed.

I started with iso9660 as I had hoped to just delete it and be done.