RFC: baseline requirements for Ubuntu rootfs: xattrs and fscaps

[Kees Cook]

On Wed, Aug 01, 2018 at 05:58:56PM -0700, Steve Langasek wrote:
>  - Where root filesystems are distributed as tarballs, they are not
>    currently created with --xattrs; this will need to be changed.

What about initramfs? CPIO doesn't support xattr:
https://lkml.kernel.org/r/1516850875-25066-1-git-send-email-takondra@cisco.com

>  - Users who are unpacking root tarballs need to take care to pass
>    --xattrs-include=* to tar.
>  - Users who are backing up or streaming Ubuntu root filesystems with tar or
>    rsync will need to take care to pass non-default xattr-preserving options
>    (tar --xattrs; rsync -X).

How about making these default-enabled? Hoping people will remember seems
fragile.

>  - GNU tar's xattrs format incompatible with other unpack implementations
>    (e.g. libarchive)[1].  Anyone using another unpacker will necessarily
>    end up without fscaps.

Seems like these unpackers should be fixed?

-Kees

-- 
Kees Cook