From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jann Horn <jannh@google.com>
Cc: "KP Singh" <kpsingh@chromium.org>,
"kernel list" <linux-kernel@vger.kernel.org>,
bpf <bpf@vger.kernel.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
"Brendan Jackman" <jackmanb@google.com>,
"Florent Revest" <revest@google.com>,
"Thomas Garnier" <thgarnie@google.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"James Morris" <jmorris@namei.org>,
"Kees Cook" <keescook@chromium.org>,
"Thomas Garnier" <thgarnie@chromium.org>,
"Michael Halcrow" <mhalcrow@google.com>,
"Paul Turner" <pjt@google.com>,
"Brendan Gregg" <brendan.d.gregg@gmail.com>,
"Matthew Garrett" <mjg59@google.com>,
"Christian Brauner" <christian@brauner.io>,
"Mickaël Salaün" <mic@digikod.net>,
"Florent Revest" <revest@chromium.org>,
"Brendan Jackman" <jackmanb@chromium.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
"Mauro Carvalho Chehab" <mchehab+samsung@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Kernel Team" <kernel-team@fb.com>
Subject: Re: BPF LSM and fexit [was: [PATCH bpf-next v3 04/10] bpf: lsm: Add mutable hooks list for the BPF LSM]
Date: Tue, 11 Feb 2020 15:26:12 -0800 [thread overview]
Message-ID: <CAADnVQLsiWgSBXbuxmpkC9TS8d1aQRw2zDHG8J6E=kfcRoXtKQ@mail.gmail.com> (raw)
In-Reply-To: <20200211213819.j4ltrjjkuywihpnv@ast-mbp>
On Tue, Feb 11, 2020 at 1:38 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Tue, Feb 11, 2020 at 09:33:49PM +0100, Jann Horn wrote:
> > >
> > > Got it. Then let's whitelist them ?
> > > All error injection points are marked with ALLOW_ERROR_INJECTION().
> > > We can do something similar here, but let's do it via BTF and avoid
> > > abusing yet another elf section for this mark.
> > > I think BTF_TYPE_EMIT() should work. Just need to pick explicit enough
> > > name and extensive comment about what is going on.
> >
> > Sounds reasonable to me. :)
>
> awesome :)
Looks like the kernel already provides this whitelisting.
$ bpftool btf dump file /sys/kernel/btf/vmlinux |grep FUNC|grep '\<security_'
gives the list of all LSM hooks that lsm-bpf will be able to attach to.
There are two exceptions there security_add_hooks() and security_init().
Both are '__init'. Too late for lsm-bpf to touch.
So filtering BTF funcs by 'security_' prefix will be enough.
It should be documented though.
The number of attachable funcs depends on kconfig which is
a nice property and further strengthen the point that
lsm-bpf is very much kernel specific.
We probably should blacklist security_bpf*() hooks though.
Otherwise inception fans will have a field day.
Disallowing bpf with bpf :)
next prev parent reply other threads:[~2020-02-11 23:26 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 15:24 [PATCH bpf-next v3 00/10] MAC and Audit policy using eBPF (KRSI) KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 01/10] bpf: btf: Add btf_type_by_name_kind KP Singh
2020-01-23 20:06 ` Andrii Nakryiko
2020-01-24 14:12 ` KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 02/10] bpf: lsm: Add a skeleton and config options KP Singh
2020-02-10 23:52 ` Alexei Starovoitov
2020-02-11 12:45 ` KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 03/10] bpf: lsm: Introduce types for eBPF based LSM KP Singh
2020-02-10 23:58 ` Alexei Starovoitov
2020-02-11 12:44 ` KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 04/10] bpf: lsm: Add mutable hooks list for the BPF LSM KP Singh
2020-01-23 17:03 ` Casey Schaufler
2020-01-23 17:59 ` KP Singh
2020-01-23 19:09 ` Casey Schaufler
2020-01-23 22:24 ` KP Singh
2020-01-23 23:50 ` Casey Schaufler
2020-01-24 1:25 ` KP Singh
2020-01-24 21:55 ` James Morris
2020-02-11 3:12 ` Alexei Starovoitov
2020-02-11 12:43 ` KP Singh
2020-02-11 17:58 ` Alexei Starovoitov
2020-02-11 18:44 ` BPF LSM and fexit [was: [PATCH bpf-next v3 04/10] bpf: lsm: Add mutable hooks list for the BPF LSM] Jann Horn
2020-02-11 19:09 ` Alexei Starovoitov
2020-02-11 19:36 ` Jann Horn
2020-02-11 20:10 ` Alexei Starovoitov
2020-02-11 20:33 ` Jann Horn
2020-02-11 21:32 ` Jann Horn
2020-02-11 21:38 ` Alexei Starovoitov
2020-02-11 23:26 ` Alexei Starovoitov [this message]
2020-02-12 0:09 ` Daniel Borkmann
2020-02-12 2:45 ` Alexei Starovoitov
2020-02-12 13:27 ` Daniel Borkmann
2020-02-12 16:04 ` KP Singh
2020-02-12 15:52 ` Casey Schaufler
2020-02-12 16:26 ` KP Singh
2020-02-12 18:59 ` Casey Schaufler
2020-01-23 15:24 ` [PATCH bpf-next v3 05/10] bpf: lsm: BTF API for LSM hooks KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 06/10] bpf: lsm: Implement attach, detach and execution KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 07/10] bpf: lsm: Make the allocated callback RO+X KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 08/10] tools/libbpf: Add support for BPF_PROG_TYPE_LSM KP Singh
2020-01-23 18:00 ` Andrii Nakryiko
2020-01-24 14:16 ` KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 09/10] bpf: lsm: Add selftests " KP Singh
2020-01-23 15:24 ` [PATCH bpf-next v3 10/10] bpf: lsm: Add Documentation KP Singh
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