Re: [RFC][PATCH 0/3] vfs: Detach mounts on unlink.

[Linus Torvalds]

On Sat, Oct 5, 2013 at 4:17 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> So learn this pattern: every time you use chroot, add a simple
>
>   chdir("/");
>
> immediately after the chroot call.

.. btw, also make sure that you close all non-essential file
descriptors. Having any open directory file descriptors pointing to
outside the chroot is also a classic escape.

Even then, escaping chroot is usually fairly easy. Making a
escape-proof chroot is really quite hard. Basically impossible if you
allow root.

                 Linus
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