From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: 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
Subject: [PATCH ebpf] bpf: Disallow unprivileged bpf by default
Date: Wed, 27 Oct 2021 13:51:49 -0700 [thread overview]
Message-ID: <d37b01e70e65dced2659561ed5bc4b2ed1a50711.1635367330.git.pawan.kumar.gupta@linux.intel.com> (raw)
Disabling unprivileged BPF by default would help prevent unprivileged
users from creating the conditions required for potential speculative
execution side-channel attacks on affected hardware as demonstrated by
[1][2][3].
This will sync mainline with what most distros are currently applying.
An admin can enable this at runtime if necessary.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
[1] https://access.redhat.com/security/cve/cve-2019-7308
[2] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3490
[3] https://bugzilla.redhat.com/show_bug.cgi?id=1672355#c5
---
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
next reply other threads:[~2021-10-27 21:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-27 20:51 Pawan Gupta [this message]
2021-10-27 21:21 ` [PATCH ebpf] bpf: Disallow unprivileged bpf by default Daniel Borkmann
2021-10-27 23:39 ` Pawan Gupta
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