From: KP Singh <kpsingh@chromium.org>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Linux Security Module list
<linux-security-module@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
James Morris <jmorris@namei.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH bpf-next v4 0/8] MAC and Audit policy using eBPF (KRSI)
Date: Fri, 21 Feb 2020 20:41:49 +0100 [thread overview]
Message-ID: <20200221194149.GA9207@chromium.org> (raw)
In-Reply-To: <85e89b0c-5f2c-a4b1-17d3-47cc3bdab38b@schaufler-ca.com>
On 21-Feb 11:19, Casey Schaufler wrote:
> On 2/20/2020 9:52 AM, KP Singh wrote:
> > From: KP Singh <kpsingh@google.com>
>
> Again, apologies for the CC list trimming.
>
> >
> > # v3 -> v4
> >
> > https://lkml.org/lkml/2020/1/23/515
> >
> > * Moved away from allocating a separate security_hook_heads and adding a
> > new special case for arch_prepare_bpf_trampoline to using BPF fexit
> > trampolines called from the right place in the LSM hook and toggled by
> > static keys based on the discussion in:
> >
> > https://lore.kernel.org/bpf/CAG48ez25mW+_oCxgCtbiGMX07g_ph79UOJa07h=o_6B6+Q-u5g@mail.gmail.com/
> >
> > * Since the code does not deal with security_hook_heads anymore, it goes
> > from "being a BPF LSM" to "BPF program attachment to LSM hooks".
>
> I've finally been able to review the entire patch set.
> I can't imagine how it can make sense to add this much
> complexity to the LSM infrastructure in support of this
> feature. There is macro magic going on that is going to
> break, and soon. You are introducing dependencies on BPF
> into the infrastructure, and that's unnecessary and most
> likely harmful.
We will be happy to document each of the macros in detail. Do note a
few things here:
* There is really nothing magical about them though, the LSM hooks are
collectively declared in lsm_hook_names.h and are used to delcare
the security_list_options and security_hook_heads for the LSM
framework (this was previously maitained in two different places):
For BPF, they declare:
* bpf_lsm_<name> attachment points and their prototypes.
* A static key (bpf_lsm_key_<name>) to enable and disable these
hooks with a function to set its value i.e.
(bpf_lsm_<name>_set_enabled).
* We have kept the BPF related macros out of security/.
* All the BPF calls in the LSM infrastructure are guarded by
CONFIG_BPF_LSM (there are only two main calls though, i.e.
call_int_hook, call_void_hook).
Honestly, the macros aren't any more complicated than
call_int_progs/call_void_progs.
- KP
>
> Would you please drop the excessive optimization? I understand
> that there's been a lot of discussion and debate about it,
> but this implementation is out of control, disruptive, and
> dangerous to the code around it.
>
>
next prev parent reply other threads:[~2020-02-21 19:41 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 17:52 [PATCH bpf-next v4 0/8] MAC and Audit policy using eBPF (KRSI) KP Singh
2020-02-20 17:52 ` [PATCH bpf-next v4 1/8] bpf: Introduce BPF_PROG_TYPE_LSM KP Singh
2020-02-20 17:52 ` [PATCH bpf-next v4 2/8] security: Refactor declaration of LSM hooks KP Singh
2020-02-20 17:52 ` [PATCH bpf-next v4 3/8] bpf: lsm: provide attachment points for BPF LSM programs KP Singh
2020-02-20 23:49 ` Casey Schaufler
2020-02-21 11:44 ` KP Singh
2020-02-21 18:23 ` Casey Schaufler
2020-02-22 4:22 ` Kees Cook
2020-02-23 22:08 ` Alexei Starovoitov
2020-02-24 16:32 ` Casey Schaufler
2020-02-24 17:13 ` KP Singh
2020-02-24 18:45 ` Casey Schaufler
2020-02-24 21:41 ` Kees Cook
2020-02-24 22:29 ` Casey Schaufler
2020-02-25 5:41 ` Alexei Starovoitov
2020-02-25 15:31 ` Kees Cook
2020-02-25 19:31 ` KP Singh
2020-02-26 0:30 ` Casey Schaufler
2020-02-26 5:15 ` KP Singh
2020-02-26 15:35 ` Casey Schaufler
2020-02-25 19:29 ` KP Singh
2020-02-24 16:09 ` Casey Schaufler
2020-02-24 17:23 ` KP Singh
2020-02-21 2:25 ` Alexei Starovoitov
2020-02-21 11:47 ` KP Singh
2020-02-20 17:52 ` [PATCH bpf-next v4 4/8] bpf: lsm: Add support for enabling/disabling BPF hooks KP Singh
2020-02-21 18:57 ` Casey Schaufler
2020-02-21 19:11 ` James Morris
2020-02-22 4:26 ` Kees Cook
2020-02-20 17:52 ` [PATCH bpf-next v4 5/8] bpf: lsm: Implement attach, detach and execution KP Singh
2020-02-21 2:17 ` Alexei Starovoitov
2020-02-21 12:02 ` KP Singh
2020-02-20 17:52 ` [PATCH bpf-next v4 6/8] tools/libbpf: Add support for BPF_PROG_TYPE_LSM KP Singh
2020-02-25 6:45 ` Andrii Nakryiko
2020-02-20 17:52 ` [PATCH bpf-next v4 7/8] bpf: lsm: Add selftests " KP Singh
2020-02-20 17:52 ` [PATCH bpf-next v4 8/8] bpf: lsm: Add Documentation KP Singh
2020-02-21 19:19 ` [PATCH bpf-next v4 0/8] MAC and Audit policy using eBPF (KRSI) Casey Schaufler
2020-02-21 19:41 ` KP Singh [this message]
2020-02-21 22:31 ` Casey Schaufler
2020-02-21 23:09 ` KP Singh
2020-02-21 23:49 ` Casey Schaufler
2020-02-22 0:22 ` Kees Cook
2020-02-22 1:04 ` Casey Schaufler
2020-02-22 3:36 ` Kees Cook
2020-02-27 18:40 ` Dr. Greg
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