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References: <20220909120736.1027040-1-roberto.sassu@huaweicloud.com> <20220909120736.1027040-8-roberto.sassu@huaweicloud.com>
In-Reply-To: <20220909120736.1027040-8-roberto.sassu@huaweicloud.com>
From:   Song Liu <song@kernel.org>
Date:   Fri, 9 Sep 2022 17:06:15 +0100
Message-ID: <CAPhsuW6zhrUJBfht7RCiUGWWCaWwpcjzAq-R4W-YmpU+YZyMXg@mail.gmail.com>
Subject: Re: [PATCH v17 07/12] bpf: Add bpf_verify_pkcs7_signature() kfunc
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>,
        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>, keyrings@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        open list <linux-kernel@vger.kernel.org>,
        =?UTF-8?Q?Daniel_M=C3=BCller?= <deso@posteo.net>,
        Kumar Kartikeya Dwivedi <memxor@gmail.com>,
        Roberto Sassu <roberto.sassu@huawei.com>
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On Fri, Sep 9, 2022 at 1:09 PM Roberto Sassu
<roberto.sassu@huaweicloud.com> wrote:
>
> From: Roberto Sassu <roberto.sassu@huawei.com>
>
> Add the bpf_verify_pkcs7_signature() kfunc, to give eBPF security modules
> the ability to check the validity of a signature against supplied data, by
> using user-provided or system-provided keys as trust anchor.
>
> The new kfunc makes it possible to enforce mandatory policies, as eBPF
> programs might be allowed to make security decisions only based on data
> sources the system administrator approves.
>
> The caller should provide the data to be verified and the signature as eBPF
> dynamic pointers (to minimize the number of parameters) and a bpf_key
> structure containing a reference to the keyring with keys trusted for
> signature verification, obtained from bpf_lookup_user_key() or
> bpf_lookup_system_key().
>
> For bpf_key structures obtained from the former lookup function,
> bpf_verify_pkcs7_signature() completes the permission check deferred by
> that function by calling key_validate(). key_task_permission() is already
> called by the PKCS#7 code.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> Acked-by: KP Singh <kpsingh@kernel.org>

Acked-by: Song Liu <song@kernel.org>

[...]