[PATCH bpf-next 3/4] bpf: Introduce path iterator

[Song Liu]

On Thu, May 29, 2025 at 9:57 AM Alexei Starovoitov
<alexei.starovoitov at gmail.com> wrote:
[...]
> >
> > How about we describe this as:
> >
> > Introduce a path iterator, which safely (no crash) walks a struct path.
> > Without malicious parallel modifications, the walk is guaranteed to
> > terminate. The sequence of dentries maybe surprising in presence
> > of parallel directory or mount tree modifications and the iteration may
> > not ever finish in face of parallel malicious directory tree manipulations.
>
> Hold on. If it's really the case then is the landlock susceptible
> to this type of attack already ?
> landlock may infinitely loop in the kernel ?

I think this only happens if the attacker can modify the mount or
directory tree as fast as the walk, which is probably impossible
in reality.

Thanks,
Song