From: Mark Rutland <mark.rutland@arm.com>
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,
gregkh@linuxfoundation.org, linux@armlinux.org.uk
Subject: Re: [PATCH ebpf v3] bpf: Disallow unprivileged bpf by default
Date: Mon, 1 Nov 2021 11:57:29 +0000 [thread overview]
Message-ID: <YX/WKa4qYamp1ml9@FVFF77S0Q05N> (raw)
In-Reply-To: <0ace9ce3f97656d5f62d11093ad7ee81190c3c25.1635535215.git.pawan.kumar.gupta@linux.intel.com>
On Fri, Oct 29, 2021 at 12:43:54PM -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].
>
> Sync with what many distros are currently applying, disable unprivileged
> BPF by default. An admin can enable this at runtime, if necessary.
>
> [1] https://ebpf.io/summit-2021-slides/eBPF_Summit_2021-Keynote-Daniel_Borkmann-BPF_and_Spectre.pdf
>
> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
FWIW:
Acked-by: Mark Rutland <mark.rutland@arm.com>
Mark.
> ---
> v3:
> - Drop the conditional default for CONFIG_BPF_UNPRIV_DEFAULT_OFF until
> we have an arch generic way to determine arch-common spectre type bugs.
> [Mark Rutland, Daniel Borkmann].
> - Also drop the patch to Generalize ARM's CONFIG_CPU_SPECTRE.
> - Minor changes to commit message.
>
> v2: https://lore.kernel.org/lkml/cover.1635383031.git.pawan.kumar.gupta@linux.intel.com/
> - Generalize ARM's CONFIG_CPU_SPECTRE to be available for all architectures.
> - Make CONFIG_BPF_UNPRIV_DEFAULT_OFF depend on CONFIG_CPU_SPECTRE.
> - Updated commit message to reflect the dependency on CONFIG_CPU_SPECTRE.
> - Add reference to BPF spectre presentation in commit message.
>
> v1: https://lore.kernel.org/all/d37b01e70e65dced2659561ed5bc4b2ed1a50711.1635367330.git.pawan.kumar.gupta@linux.intel.com/
>
> kernel/bpf/Kconfig | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
> index a82d6de86522..73d446294455 100644
> --- a/kernel/bpf/Kconfig
> +++ b/kernel/bpf/Kconfig
> @@ -64,6 +64,7 @@ config BPF_JIT_DEFAULT_ON
>
> config BPF_UNPRIV_DEFAULT_OFF
> bool "Disable unprivileged BPF by default"
> + default y
> depends on BPF_SYSCALL
> help
> Disables unprivileged BPF by default by setting the corresponding
> @@ -72,6 +73,10 @@ config BPF_UNPRIV_DEFAULT_OFF
> disable it by setting it to 1 (from which no other transition to
> 0 is possible anymore).
>
> + Unprivileged BPF can be used to exploit potential speculative
> + execution side-channel vulnerabilities on affected hardware. If you
> + are concerned about it, answer Y.
> +
> source "kernel/bpf/preload/Kconfig"
>
> config BPF_LSM
> --
> 2.31.1
>
prev parent reply other threads:[~2021-11-01 11:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-29 19:43 [PATCH ebpf v3] bpf: Disallow unprivileged bpf by default Pawan Gupta
2021-11-01 11:57 ` Mark Rutland [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YX/WKa4qYamp1ml9@FVFF77S0Q05N \
--to=mark.rutland@arm.com \
--cc=andrii@kernel.org \
--cc=antonio.gomez.iglesias@intel.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=dave.hansen@linux.intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kpsingh@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=netdev@vger.kernel.org \
--cc=pawan.kumar.gupta@linux.intel.com \
--cc=songliubraving@fb.com \
--cc=tony.luck@intel.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).