From: Stephen Smalley <stephen.smalley.work@gmail.com>
To: KP Singh <kpsingh@chromium.org>
Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
LSM List <linux-security-module@vger.kernel.org>,
Brendan Jackman <jackmanb@google.com>,
Florent Revest <revest@google.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
James Morris <jmorris@namei.org>,
Kees Cook <keescook@chromium.org>, Paul Turner <pjt@google.com>,
Jann Horn <jannh@google.com>,
Florent Revest <revest@chromium.org>,
Brendan Jackman <jackmanb@chromium.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Paul Moore <paul@paul-moore.com>
Subject: Re: [PATCH bpf-next v5 4/7] bpf: lsm: Implement attach, detach and execution
Date: Tue, 24 Mar 2020 10:58:12 -0400 [thread overview]
Message-ID: <CAEjxPJ4YnCCeQUTK36Ao550AWProHrkrW1a6K5RKuKYcPcfhyA@mail.gmail.com> (raw)
In-Reply-To: <20200324145003.GA2685@chromium.org>
On Tue, Mar 24, 2020 at 10:50 AM KP Singh <kpsingh@chromium.org> wrote:
>
> On 24-Mär 10:35, Stephen Smalley wrote:
> > On Mon, Mar 23, 2020 at 12:46 PM KP Singh <kpsingh@chromium.org> wrote:
> > >
> > > From: KP Singh <kpsingh@google.com>
> > > diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
> > > index 530d137f7a84..2a8131b640b8 100644
> > > --- a/kernel/bpf/bpf_lsm.c
> > > +++ b/kernel/bpf/bpf_lsm.c
> > > @@ -9,6 +9,9 @@
> > > #include <linux/btf.h>
> > > #include <linux/lsm_hooks.h>
> > > #include <linux/bpf_lsm.h>
> > > +#include <linux/jump_label.h>
> > > +#include <linux/kallsyms.h>
> > > +#include <linux/bpf_verifier.h>
> > >
> > > /* For every LSM hook that allows attachment of BPF programs, declare a NOP
> > > * function where a BPF program can be attached as an fexit trampoline.
> > > @@ -27,6 +30,32 @@ noinline __weak void bpf_lsm_##NAME(__VA_ARGS__) {}
> > > #include <linux/lsm_hook_names.h>
> > > #undef LSM_HOOK
> > >
> > > +#define BPF_LSM_SYM_PREFX "bpf_lsm_"
> > > +
> > > +int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
> > > + const struct bpf_prog *prog)
> > > +{
> > > + /* Only CAP_MAC_ADMIN users are allowed to make changes to LSM hooks
> > > + */
> > > + if (!capable(CAP_MAC_ADMIN))
> > > + return -EPERM;
> >
> > I had asked before, and will ask again: please provide an explicit LSM
> > hook for mediating whether one can make changes to the LSM hooks.
> > Neither CAP_MAC_ADMIN nor CAP_SYS_ADMIN suffices to check this for SELinux.
>
> What do you think about:
>
> int security_check_mutable_hooks(void)
>
> Do you have any suggestions on the signature of this hook? Does this
> hook need to be BPF specific?
I'd do something like int security_bpf_prog_attach_security(const
struct bpf_prog *prog) or similar.
Then the security module can do a check based on the current task
and/or the prog. We already have some bpf-specific hooks.
next prev parent reply other threads:[~2020-03-24 14:57 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 16:44 [PATCH bpf-next v5 0/8] MAC and Audit policy using eBPF (KRSI) KP Singh
2020-03-23 16:44 ` [PATCH bpf-next v5 1/7] bpf: Introduce BPF_PROG_TYPE_LSM KP Singh
2020-03-23 19:02 ` Yonghong Song
2020-03-23 16:44 ` [PATCH bpf-next v5 2/7] security: Refactor declaration of LSM hooks KP Singh
2020-03-23 19:33 ` Kees Cook
2020-03-23 19:56 ` Andrii Nakryiko
2020-03-24 16:06 ` KP Singh
2020-03-23 16:44 ` [PATCH bpf-next v5 3/7] bpf: lsm: provide attachment points for BPF LSM programs KP Singh
2020-03-23 19:04 ` Yonghong Song
2020-03-23 19:33 ` Kees Cook
2020-03-23 19:59 ` Andrii Nakryiko
2020-03-24 10:39 ` KP Singh
2020-03-24 16:12 ` KP Singh
2020-03-24 21:26 ` Andrii Nakryiko
2020-03-24 22:39 ` KP Singh
2020-03-23 16:44 ` [PATCH bpf-next v5 4/7] bpf: lsm: Implement attach, detach and execution KP Singh
2020-03-23 19:16 ` Yonghong Song
2020-03-23 19:44 ` KP Singh
2020-03-23 20:18 ` Andrii Nakryiko
2020-03-24 19:00 ` KP Singh
2020-03-24 14:35 ` Stephen Smalley
2020-03-24 14:50 ` KP Singh
2020-03-24 14:58 ` Stephen Smalley [this message]
2020-03-24 16:25 ` Casey Schaufler
2020-03-24 17:49 ` Stephen Smalley
2020-03-24 18:01 ` Kees Cook
2020-03-24 18:06 ` KP Singh
2020-03-24 18:21 ` Stephen Smalley
2020-03-24 18:27 ` KP Singh
2020-03-24 18:31 ` KP Singh
2020-03-24 18:34 ` Kees Cook
2020-03-24 18:33 ` Kees Cook
2020-03-23 16:44 ` [PATCH bpf-next v5 5/7] bpf: lsm: Initialize the BPF LSM hooks KP Singh
2020-03-23 19:44 ` Kees Cook
2020-03-23 19:47 ` KP Singh
2020-03-23 20:21 ` Andrii Nakryiko
2020-03-23 20:47 ` Casey Schaufler
2020-03-23 21:44 ` Kees Cook
2020-03-23 21:58 ` Casey Schaufler
2020-03-23 22:12 ` Kees Cook
2020-03-23 23:39 ` Casey Schaufler
2020-03-24 1:53 ` KP Singh
2020-03-25 14:35 ` KP Singh
2020-03-24 1:13 ` Casey Schaufler
2020-03-24 1:52 ` KP Singh
2020-03-24 14:37 ` Stephen Smalley
2020-03-24 14:42 ` KP Singh
2020-03-24 14:51 ` Stephen Smalley
2020-03-24 14:51 ` KP Singh
2020-03-24 17:57 ` Kees Cook
2020-03-23 16:44 ` [PATCH bpf-next v5 6/7] tools/libbpf: Add support for BPF_PROG_TYPE_LSM KP Singh
2020-03-23 19:21 ` Yonghong Song
2020-03-23 20:25 ` Andrii Nakryiko
2020-03-24 1:57 ` KP Singh
2020-03-23 16:44 ` [PATCH bpf-next v5 7/7] bpf: lsm: Add selftests " KP Singh
2020-03-23 20:04 ` Yonghong Song
2020-03-24 20:04 ` KP Singh
2020-03-24 23:54 ` Andrii Nakryiko
2020-03-25 0:36 ` KP Singh
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