Re: [PATCH v13 05/10] bpf: Add bpf_lookup_*_key() and bpf_key_put() kfuncs

From: Song Liu <song@kernel.org>
To: Roberto Sassu <roberto.sassu@huaweicloud.com>
Cc: "Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Martin KaFai Lau" <martin.lau@linux.dev>,
	"Yonghong Song" <yhs@fb.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"KP Singh" <kpsingh@kernel.org>,
	"Stanislav Fomichev" <sdf@google.com>,
	"Hao Luo" <haoluo@google.com>, "Jiri Olsa" <jolsa@kernel.org>,
	"Mykola Lysenko" <mykolal@fb.com>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"David Howells" <dhowells@redhat.com>,
	"Jarkko Sakkinen" <jarkko@kernel.org>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com,
	"Shuah Khan" <shuah@kernel.org>, bpf <bpf@vger.kernel.org>,
	"Linux Doc Mailing List" <linux-doc@vger.kernel.org>,
	keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	"open list" <linux-kernel@vger.kernel.org>,
	"Daniel Müller" <deso@posteo.net>,
	"Roberto Sassu" <roberto.sassu@huawei.com>
Subject: Re: [PATCH v13 05/10] bpf: Add bpf_lookup_*_key() and bpf_key_put() kfuncs
Date: Fri, 26 Aug 2022 00:25:41 -0700	[thread overview]
Message-ID: <CAPhsuW76kwaX2mhDtp3_5cC+gxsB3tnVQ00CUrjAR6bFKBcFtQ@mail.gmail.com> (raw)
In-Reply-To: <67c4a5e7cf363a6c9b79a436690c4c3f469652de.camel@huaweicloud.com>

On Fri, Aug 26, 2022 at 12:22 AM Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
>
> On Thu, 2022-08-25 at 22:56 -0700, Song Liu wrote:
> > On Tue, Aug 23, 2022 at 8:02 AM Roberto Sassu
> > <roberto.sassu@huaweicloud.com> wrote:
> > > From: Roberto Sassu <roberto.sassu@huawei.com>
> > >
> > > Add the bpf_lookup_user_key(), bpf_lookup_system_key() and
> > > bpf_key_put()
> > > kfuncs, to respectively search a key with a given key handle serial
> > > number
> > > and flags, obtain a key from a pre-determined ID defined in
> > > include/linux/verification.h, and cleanup.
> > >
> > > Introduce system_keyring_id_check() to validate the keyring ID
> > > parameter of
> > > bpf_lookup_system_key().
> > >
> > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > > ---
> > >  include/linux/bpf.h          |   6 ++
> > >  include/linux/verification.h |   8 +++
> > >  kernel/trace/bpf_trace.c     | 135
> > > +++++++++++++++++++++++++++++++++++
> > >  3 files changed, 149 insertions(+)
> > >
> > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > > index 6041304b402e..991da09a5858 100644
> > > --- a/include/linux/bpf.h
> > > +++ b/include/linux/bpf.h
> > > @@ -2586,4 +2586,10 @@ static inline void bpf_cgroup_atype_get(u32
> > > attach_btf_id, int cgroup_atype) {}
> > >  static inline void bpf_cgroup_atype_put(int cgroup_atype) {}
> > >  #endif /* CONFIG_BPF_LSM */
> > >
> > > +#ifdef CONFIG_KEYS
> >
> > Do we need to declare struct key here?
> >
> > > +struct bpf_key {
> > > +       struct key *key;
> > > +       bool has_ref;
> > > +};
> > > +#endif /* CONFIG_KEYS */
> > >  #endif /* _LINUX_BPF_H */
> > >
>
> If there is a better place, I will move there.

I guess you misunderstood. I meant we need

struct key;

struct bpf_key {
       struct key *key;
       bool has_ref;
};

Otherwise, we may get some warning with certain config.

Thanks,
Song