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References: <20220610135916.1285509-1-roberto.sassu@huawei.com> <20220610135916.1285509-2-roberto.sassu@huawei.com>
In-Reply-To: <20220610135916.1285509-2-roberto.sassu@huawei.com>
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Fri, 10 Jun 2022 09:30:26 -0700
Message-ID: <CAADnVQKWS5kQ-ekzDFV=2+y9kkCYCKaAStNJhAr6G2G-N6Q+9w@mail.gmail.com>
Subject: Re: [PATCH v3 1/2] bpf: Add bpf_verify_signature() helper
To:     Roberto Sassu <roberto.sassu@huawei.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        KP Singh <kpsingh@kernel.org>, bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kernel test robot <lkp@intel.com>
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On Fri, Jun 10, 2022 at 6:59 AM Roberto Sassu <roberto.sassu@huawei.com> wrote:
> +       keyring = (keyring_id == U16_MAX) ?
> +                 cred->session_keyring : (struct key *)keyring_id;

This is too limiting.
bpf prog should be able to do what *key syscalls can do.
By doing lookup_user_key(id) -> keyring.
Maybe it's ok to have a special reserved id that does
cred->sessions_keyring as a shortcut, but that's an optimization.