Re: [PATCH RFC 0/1] mount: universally disallow mounting over symlinks

On 2020-01-01, Al Viro viro@zeniv.linux.org.uk wrote:

On Thu, Jan 02, 2020 at 01:44:07AM +1100, Aleksa Sarai wrote:

...

Thanks, this fixes the issue for me (and also fixes another reproducer I found -- mounting a symlink on top of itself then trying to umount it).

Reported-by: Aleksa Sarai cyphar@cyphar.com Tested-by: Aleksa Sarai cyphar@cyphar.com

Pushed into #fixes.

Thanks. One other thing I noticed is that umount applies to the underlying symlink rather than the mountpoint on top. So, for example (using the same scripts I posted in the thread):

# ln -s /tmp/foo link # ./mount_to_symlink /etc/passwd link # umount -l link # will attempt to unmount "/tmp/foo"

Is that intentional?