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

- From: Aleksa Sarai \<hidden\>
- Date: 2020-01-02 03:59:42 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2020/01/169810
- Thread: https://ratatoskr.run/stable/2019/12/169751/t.md

```text
On 2020-01-01, Al Viro [ref] 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 <redacted>
> > Tested-by: Aleksa Sarai <redacted>
> 
> 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?

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>
```

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