Messages in this thread | | | Date | Wed, 25 Mar 2020 12:28:59 -0700 | From | Kees Cook <> | Subject | Re: [PATCH bpf-next v6 3/8] bpf: lsm: provide attachment points for BPF LSM programs |
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On Wed, Mar 25, 2020 at 04:26:24PM +0100, KP Singh wrote: > From: KP Singh <kpsingh@google.com> > > When CONFIG_BPF_LSM is enabled, nop functions, bpf_lsm_<hook_name>, are > generated for each LSM hook. These functions are initialized as LSM > hooks in a subsequent patch. > > Signed-off-by: KP Singh <kpsingh@google.com> > Reviewed-by: Brendan Jackman <jackmanb@google.com> > Reviewed-by: Florent Revest <revest@google.com> > Reviewed-by: Kees Cook <keescook@chromium.org> > Acked-by: Yonghong Song <yhs@fb.com> > --- > include/linux/bpf_lsm.h | 22 ++++++++++++++++++++++ > kernel/bpf/bpf_lsm.c | 14 ++++++++++++++ > 2 files changed, 36 insertions(+) > create mode 100644 include/linux/bpf_lsm.h > > diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h > new file mode 100644 > index 000000000000..83b96895829f > --- /dev/null > +++ b/include/linux/bpf_lsm.h > @@ -0,0 +1,22 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +/* > + * Copyright (C) 2020 Google LLC. > + */ > + > +#ifndef _LINUX_BPF_LSM_H > +#define _LINUX_BPF_LSM_H > + > +#include <linux/bpf.h> > +#include <linux/lsm_hooks.h> > + > +#ifdef CONFIG_BPF_LSM > + > +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ > + RET bpf_lsm_##NAME(__VA_ARGS__); > +#include <linux/lsm_hook_defs.h> > +#undef LSM_HOOK > + > +#endif /* CONFIG_BPF_LSM */ > + > +#endif /* _LINUX_BPF_LSM_H */ > diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c > index 82875039ca90..1210a819ca52 100644 > --- a/kernel/bpf/bpf_lsm.c > +++ b/kernel/bpf/bpf_lsm.c > @@ -7,6 +7,20 @@ > #include <linux/filter.h> > #include <linux/bpf.h> > #include <linux/btf.h> > +#include <linux/lsm_hooks.h> > +#include <linux/bpf_lsm.h> > + > +/* For every LSM hook that allows attachment of BPF programs, declare a nop > + * function where a BPF program can be attached. > + */ > +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ > +noinline __weak RET bpf_lsm_##NAME(__VA_ARGS__) \
I don't think the __weak is needed any more here?
> +{ \ > + return DEFAULT; \
I'm impressed that LSM_RET_VOID actually works. :)
-Kees
> +} > + > +#include <linux/lsm_hook_defs.h> > +#undef LSM_HOOK > > const struct bpf_prog_ops lsm_prog_ops = { > }; > -- > 2.20.1 >
-- Kees Cook
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