Re: [PATCH net-next v4 2/4] net: socket: add sockopts blacklist for BPF cgroup hook

[Stanislav Fomichev]

On Thu, Apr 13, 2023 at 7:38 AM Aleksandr Mikhalitsyn
<aleksandr.mikhalitsyn@xxxxxxxxxxxxx> wrote:
>
> On Thu, Apr 13, 2023 at 4:22 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
> >
> > On Thu, Apr 13, 2023 at 3:35 PM Alexander Mikhalitsyn
> > <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> wrote:
> > >
> > > During work on SO_PEERPIDFD, it was discovered (thanks to Christian),
> > > that bpf cgroup hook can cause FD leaks when used with sockopts which
> > > install FDs into the process fdtable.
> > >
> > > After some offlist discussion it was proposed to add a blacklist of
> >
> > We try to replace this word by either denylist or blocklist, even in changelogs.
>
> Hi Eric,
>
> Oh, I'm sorry about that. :( Sure.
>
> >
> > > socket options those can cause troubles when BPF cgroup hook is enabled.
> > >
> >
> > Can we find the appropriate Fixes: tag to help stable teams ?
>
> Sure, I will add next time.
>
> Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks")
>
> I think it's better to add Stanislav Fomichev to CC.

Can we use 'struct proto' bpf_bypass_getsockopt instead? We already
use it for tcp zerocopy, I'm assuming it should work in this case as
well?

> Kind regards,
> Alex
>
> >
> > > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> > > Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> > > Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> > > Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> > > Cc: Leon Romanovsky <leon@xxxxxxxxxx>
> > > Cc: David Ahern <dsahern@xxxxxxxxxx>
> > > Cc: Arnd Bergmann <arnd@xxxxxxxx>
> > > Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> > > Cc: Christian Brauner <brauner@xxxxxxxxxx>
> > > Cc: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
> > > Cc: Lennart Poettering <mzxreary@xxxxxxxxxxx>
> > > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > > Cc: netdev@xxxxxxxxxxxxxxx
> > > Cc: linux-arch@xxxxxxxxxxxxxxx
> > > Suggested-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > > Suggested-by: Christian Brauner <brauner@xxxxxxxxxx>
> > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
> >
> > Thanks.