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Date:   Thu, 28 Oct 2021 07:34:02 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        antonio.gomez.iglesias@intel.com, tony.luck@intel.com,
        dave.hansen@linux.intel.com
Subject: Re: [PATCH ebpf v2 2/2] bpf: Make unprivileged bpf depend on
 CONFIG_CPU_SPECTRE
Message-ID: <YXo2SpgjcsDzsD9O@kroah.com>
References: <cover.1635383031.git.pawan.kumar.gupta@linux.intel.com>
 <882f5c31f48bac75ebaede2a0ec321ec67128229.1635383031.git.pawan.kumar.gupta@linux.intel.com>
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On Wed, Oct 27, 2021 at 06:35:44PM -0700, Pawan Gupta wrote:
> Disabling unprivileged BPF would help prevent unprivileged users from
> creating the conditions required for potential speculative execution
> side-channel attacks on affected hardware. A deep dive on such attacks
> and mitigation is available here [1].
> 
> If an architecture selects CONFIG_CPU_SPECTRE, disable unprivileged BPF
> by default. An admin can enable this at runtime, if necessary.
> 
> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> 
> [1] https://ebpf.io/summit-2021-slides/eBPF_Summit_2021-Keynote-Daniel_Borkmann-BPF_and_Spectre.pdf

This should go above the signed-off-by line, in the changelog text, not
below it, otherwise our tools get confused when trying to apply it.

thanks,

greg k-h