From: Andrey Ignatov <rdna@fb.com>
To: Kees Cook <keescook@chromium.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Network Development <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
Roman Gushchin <guro@fb.com>, Kernel Team <Kernel-team@fb.com>,
Luis Chamberlain <mcgrof@kernel.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
Jann Horn <jannh@google.com>
Subject: Re: [PATCH v3 bpf-next 00/21] bpf: Sysctl hook
Date: Tue, 9 Apr 2019 23:17:31 +0000 [thread overview]
Message-ID: <20190409231729.GB59615@rdna-mbp> (raw)
In-Reply-To: <CAGXu5jJTCjE6FiqPgnSZbp1rzNs35RV-bXXg=+Nu5bO7v1Ac0g@mail.gmail.com>
Kees Cook <keescook@chromium.org> [Tue, 2019-04-09 09:51 -0700]:
> On Sat, Apr 6, 2019 at 10:03 AM Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
> >
> > On Sat, Apr 06, 2019 at 09:43:50AM -0700, Kees Cook wrote:
> > > On Fri, Apr 5, 2019 at 12:36 PM Andrey Ignatov <rdna@fb.com> wrote:
> > > Can the BPF be removed (or rather,
> > > what's the lifetime of such BPF?)
> >
> > same as all other cgroup-bpf hooks.
> > Do you have a specific concern or just asking how life time of programs
> > is managed?
> > High level description of lifetime is here:
> > https://urldefense.proofpoint.com/v2/url?u=https-3A__facebookmicrosites.github.io_bpf_blog_2018_08_31_object-2Dlifetime.html&d=DwIBaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=3jAokpHyGuCuJ834j-tttQ&m=ZJJ4QMXnksL1b4VPoBM0NJ0i6OWysGc2Om26pcoJpxA&s=6dIZ788hOzoDWVif5XQ-9Mqf9ijko9O7TOWArLzblxU&e=
>
> I'm mostly curious about the access control stacking. i.e. can
> in-container root add new eBPF to its own cgroup, and if so, can it
> undo the restrictions already present? (I assume it can't, but figured
> I'd ask...)
Since I answered similar question from Jann below, I'll answer it here
as well (even though it was addressed to Alexei).
Stacking can be controlled by attach flags (NONE, BPF_F_ALLOW_OVERRIDE,
BPF_F_ALLOW_MULTI) described in include/uapi/linux/bpf.h.
Basically if one attaches a program to a cgroup with
`bpf_attr.attach_flags = 0` (0 is "NONE"), then nobody can override it
by their own programs of same type in any sub-cgroup. It can be hardened
further by cgroup namespace so that in-container root doesn't even see
part of cgroup hierarchy where cgroup-bpf program is attached to with
attach flags NONE.
--
Andrey Ignatov
next prev parent reply other threads:[~2019-04-09 23:18 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-05 19:35 [PATCH v3 bpf-next 00/21] bpf: Sysctl hook Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 01/21] bpf: Add base proto function for cgroup-bpf programs Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 02/21] bpf: Sysctl hook Andrey Ignatov
2019-04-09 16:54 ` Kees Cook
2019-04-09 20:16 ` Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 03/21] bpf: Introduce bpf_sysctl_get_name helper Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 04/21] bpf: Introduce bpf_sysctl_get_current_value helper Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 05/21] bpf: Introduce bpf_sysctl_{get,set}_new_value helpers Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 06/21] bpf: Add file_pos field to bpf_sysctl ctx Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 07/21] bpf: Sync bpf.h to tools/ Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 08/21] libbpf: Support sysctl hook Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 09/21] selftests/bpf: Test sysctl section name Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 10/21] selftests/bpf: Test BPF_CGROUP_SYSCTL Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 11/21] selftests/bpf: Test bpf_sysctl_get_name helper Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 12/21] selftests/bpf: Test sysctl_get_current_value helper Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 13/21] selftests/bpf: Test bpf_sysctl_{get,set}_new_value helpers Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 14/21] selftests/bpf: Test file_pos field in bpf_sysctl ctx Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 15/21] bpf: Introduce ARG_PTR_TO_{INT,LONG} arg types Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 16/21] bpf: Introduce bpf_strtol and bpf_strtoul helpers Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 17/21] bpf: Sync bpf.h to tools/ Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 18/21] selftests/bpf: Add sysctl and strtoX helpers to bpf_helpers.h Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 19/21] selftests/bpf: Test ARG_PTR_TO_LONG arg type Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 20/21] selftests/bpf: Test bpf_strtol and bpf_strtoul helpers Andrey Ignatov
2019-04-05 19:35 ` [PATCH v3 bpf-next 21/21] selftests/bpf: C based test for sysctl and strtoX Andrey Ignatov
2019-04-06 16:43 ` [PATCH v3 bpf-next 00/21] bpf: Sysctl hook Kees Cook
2019-04-06 17:02 ` Alexei Starovoitov
2019-04-09 16:50 ` Kees Cook
2019-04-09 23:17 ` Andrey Ignatov [this message]
2019-04-09 20:41 ` Jann Horn
2019-04-09 23:04 ` Andrey Ignatov
2019-04-09 23:22 ` Jann Horn
2019-04-09 23:34 ` Alexei Starovoitov
2019-04-12 21:27 ` Alexei Starovoitov
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