From: Kees Cook <keescook@chromium.org>
To: Andrey Ignatov <rdna@fb.com>
Cc: 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: Sat, 6 Apr 2019 09:43:50 -0700 [thread overview]
Message-ID: <CAGXu5jJGC1kB-0e3DimBSprcgEBnWRB=i287g-9T5a-RidFqBg@mail.gmail.com> (raw)
In-Reply-To: <cover.1554485409.git.rdna@fb.com>
On Fri, Apr 5, 2019 at 12:36 PM Andrey Ignatov <rdna@fb.com> wrote:
>
> v2->v3:
> - simplify C based selftests by relying on variable offset stack access.
>
> v1->v2:
> - add fs/proc/proc_sysctl.c mainteners to Cc:.
>
> The patch set introduces new BPF hook for sysctl.
>
> It adds new program type BPF_PROG_TYPE_CGROUP_SYSCTL and attach type
> BPF_CGROUP_SYSCTL.
>
> BPF_CGROUP_SYSCTL hook is placed before calling to sysctl's proc_handler so
> that accesses (read/write) to sysctl can be controlled for specific cgroup
> and either allowed or denied, or traced.
>
> The hook has access to sysctl name, current sysctl value and (on write
> only) to new sysctl value via corresponding helpers. New sysctl value can
> be overridden by program. Both name and values (current/new) are
> represented as strings same way they're visible in /proc/sys/. It is up to
> program to parse these strings.
>
> To help with parsing the most common kind of sysctl value, vector of
> integers, two new helpers are provided: bpf_strtol and bpf_strtoul with
> semantic similar to user space strtol(3) and strtoul(3).
>
> The hook also provides bpf_sysctl context with two fields:
> * @write indicates whether sysctl is being read (= 0) or written (= 1);
> * @file_pos is sysctl file position to read from or write to, can be
> overridden.
>
> The hook allows to make better isolation for containerized applications
> that are run as root so that one container can't change a sysctl and affect
> all other containers on a host, make changes to allowed sysctl in a safer
> way and simplify sysctl tracing for cgroups.
This sounds more like an LSM than BPF. So sysctls can get blocked when
new BPF is added to a cgroup? Can the BPF be removed (or rather,
what's the lifetime of such BPF?)
--
Kees Cook
next prev parent reply other threads:[~2019-04-06 16:44 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 ` Kees Cook [this message]
2019-04-06 17:02 ` [PATCH v3 bpf-next 00/21] bpf: Sysctl hook Alexei Starovoitov
2019-04-09 16:50 ` Kees Cook
2019-04-09 23:17 ` Andrey Ignatov
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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