From: Andy Lutomirski <luto@amacapital.net>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: "Andy Lutomirski" <luto@kernel.org>,
"Daniel Mack" <daniel@zonque.org>,
"Mickaël Salaün" <mic@digikod.net>,
"Kees Cook" <keescook@chromium.org>, "Jann Horn" <jann@thejh.net>,
"Tejun Heo" <tj@kernel.org>, "David Ahern" <dsahern@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
"Thomas Graf" <tgraf@suug.ch>,
"Michael Kerrisk" <mtk.manpages@gmail.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Linux API" <linux-api@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Network Development" <netdev@vger.kernel.org>
Subject: Re: Potential issues (security and otherwise) with the current cgroup-bpf API
Date: Mon, 19 Dec 2016 17:43:43 -0800 [thread overview]
Message-ID: <CALCETrUhJbc90xnNJJyWEMTdah4_C4qaf+tFu5-OJSvJgwZtMA@mail.gmail.com> (raw)
In-Reply-To: <CALCETrU1_bDVLfokQ7zasHVmeq7S-R+603GEw59V_wuj4eE1hw@mail.gmail.com>
On Mon, Dec 19, 2016 at 4:25 PM, Andy Lutomirski <luto@amacapital.net> wrote:
> On Mon, Dec 19, 2016 at 4:02 PM, Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
>> you're ignoring use cases I described earlier.
>> In vrf case there is only one ifindex it needs to bind to.
>
> I'm totally lost. Can you explain what this has to do with the cgroup
> hierarchy?
>
Okay, I figured out what you mean, I think. You have a handful of vrf
devices. Let's say they have ifindexes 1 and 2 (and maybe more).
The interesting case happens when you set up /cgroup/a with a bpf
program that binds new sockets to ifindex 1 and /cgroup/a/b with a bpf
program that binds new sockets to ifindex 2. The question is: what
should happen if you're in /cgroup/a/b? Presumably, if you do this,
you wanted to end up with ifindex 2.
I think the way it should actually work is that the kernel evaluates
/cgroup/a/b's hook and then /cgroup/a's hook. Then /cgroup/a (which
is the more privileged hook) gets to make the choice. If it wants
ifindex 2 to win, it can do (pseudocode):
if (!sk->sk_bound_if)
sk->sk_bound_if = 1;
next prev parent reply other threads:[~2016-12-20 1:44 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-17 18:18 Potential issues (security and otherwise) with the current cgroup-bpf API Andy Lutomirski
2016-12-17 19:26 ` Mickaël Salaün
2016-12-17 20:02 ` Andy Lutomirski
2016-12-19 20:56 ` Alexei Starovoitov
2016-12-19 21:23 ` Andy Lutomirski
2016-12-20 0:02 ` Alexei Starovoitov
2016-12-20 0:25 ` Andy Lutomirski
2016-12-20 1:43 ` Andy Lutomirski [this message]
2016-12-20 1:44 ` David Ahern
2016-12-20 1:56 ` Andy Lutomirski
2016-12-20 2:52 ` David Ahern
2016-12-20 3:12 ` Andy Lutomirski
2016-12-20 4:44 ` Alexei Starovoitov
2016-12-20 5:27 ` Andy Lutomirski
2016-12-20 5:32 ` Alexei Starovoitov
2016-12-20 9:11 ` Peter Zijlstra
2017-01-03 10:25 ` Michal Hocko
2017-01-16 1:19 ` Tejun Heo
2017-01-17 13:03 ` Michal Hocko
2017-01-17 13:32 ` Peter Zijlstra
2017-01-17 13:58 ` Michal Hocko
2017-01-17 20:23 ` Andy Lutomirski
2017-01-18 22:18 ` Tejun Heo
2017-01-19 9:00 ` Michal Hocko
2016-12-20 3:18 ` Alexei Starovoitov
2016-12-20 3:50 ` Andy Lutomirski
2016-12-20 4:41 ` Alexei Starovoitov
2016-12-20 10:21 ` Daniel Mack
2016-12-20 17:23 ` Andy Lutomirski
2016-12-20 18:36 ` Daniel Mack
2016-12-20 18:49 ` Andy Lutomirski
2016-12-21 4:01 ` Alexei Starovoitov
2016-12-20 1:34 ` David Miller
2016-12-20 1:40 ` Andy Lutomirski
2016-12-20 4:51 ` Alexei Starovoitov
2016-12-20 5:26 ` Andy Lutomirski
2017-01-17 5:18 Andy Lutomirski
2017-01-18 22:41 ` Potential issues (security and otherwise) with the current cgroup-bpf API Tejun Heo
2017-01-19 0:18 ` Andy Lutomirski
2017-01-19 0:59 ` Tejun Heo
2017-01-19 2:29 ` Andy Lutomirski
2017-01-20 2:39 ` Alexei Starovoitov
2017-01-20 4:04 ` Andy Lutomirski
2017-01-23 4:31 ` Alexei Starovoitov
2017-01-23 20:20 ` Andy Lutomirski
2017-02-03 21:07 ` Andy Lutomirski
2017-02-03 23:21 ` Alexei Starovoitov
2017-02-04 17:10 ` Andy Lutomirski
2017-01-19 1:01 ` Mickaël Salaün
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