Message-ID: <2025050215-CVE-2023-53076-d1a7@gregkh>
Date: Fri,  2 May 2025 17:55:41 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53076: bpf: Adjust insufficient default bpf_jit_limit

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

bpf: Adjust insufficient default bpf_jit_limit

We've seen recent AWS EKS (Kubernetes) user reports like the following:

  After upgrading EKS nodes from v20230203 to v20230217 on our 1.24 EKS
  clusters after a few days a number of the nodes have containers stuck
  in ContainerCreating state or liveness/readiness probes reporting the
  following error:

    Readiness probe errored: rpc error: code = Unknown desc = failed to
    exec in container: failed to start exec "4a11039f730203ffc003b7[...]":
    OCI runtime exec failed: exec failed: unable to start container process:
    unable to init seccomp: error loading seccomp filter into kernel:
    error loading seccomp filter: errno 524: unknown

  However, we had not been seeing this issue on previous AMIs and it only
  started to occur on v20230217 (following the upgrade from kernel 5.4 to
  5.10) with no other changes to the underlying cluster or workloads.

  We tried the suggestions from that issue (sysctl net.core.bpf_jit_limit=452534528)
  which helped to immediately allow containers to be created and probes to
  execute but after approximately a day the issue returned and the value
  returned by cat /proc/vmallocinfo | grep bpf_jit | awk '{s+=$2} END {print s}'
  was steadily increasing.

I tested bpf tree to observe bpf_jit_charge_modmem, bpf_jit_uncharge_modmem
their sizes passed in as well as bpf_jit_current under tcpdump BPF filter,
seccomp BPF and native (e)BPF programs, and the behavior all looks sane
and expected, that is nothing "leaking" from an upstream perspective.

The bpf_jit_limit knob was originally added in order to avoid a situation
where unprivileged applications loading BPF programs (e.g. seccomp BPF
policies) consuming all the module memory space via BPF JIT such that loading
of kernel modules would be prevented. The default limit was defined back in
2018 and while good enough back then, we are generally seeing far more BPF
consumers today.

Adjust the limit for the BPF JIT pool from originally 1/4 to now 1/2 of the
module memory space to better reflect today's needs and avoid more users
running into potentially hard to debug issues.

The Linux kernel CVE team has assigned CVE-2023-53076 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 4.14.140 with commit 2d45c6f193789c6b610d734997a2f4cdebec4e37 and fixed in 4.14.312 with commit 374ed036309fce73f9db04c3054018a71912d46b
	Issue introduced in 4.19.58 with commit 54e8cf41b20b9e9952c7e563794efcbc5d47e891 and fixed in 4.19.280 with commit 42049e65d338870e93732b0b80c6c41faf6aa781
	Issue introduced in 4.20 with commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 and fixed in 5.4.240 with commit d69c2ded95b17d51cc6632c7848cbd476381ecd6
	Issue introduced in 4.20 with commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 and fixed in 5.10.177 with commit a4bbab27c4bf69486f5846d44134eb31c37e9b22
	Issue introduced in 4.20 with commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 and fixed in 5.15.105 with commit 54869daa6a437887614274f65298ba44a3fac63a
	Issue introduced in 4.20 with commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 and fixed in 6.1.22 with commit 9cda812c76067c8a771eae43bb6943481cc7effc
	Issue introduced in 4.20 with commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 and fixed in 6.2.9 with commit 68ed00a37d2d1c932ff7be40be4b90c4bec48c56
	Issue introduced in 4.20 with commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 and fixed in 6.3 with commit 10ec8ca8ec1a2f04c4ed90897225231c58c124a7
	Issue introduced in 4.9.190 with commit 6c1dc8f96b54ad9e63ef3becac73750a588abe6e

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2023-53076
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	kernel/bpf/core.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/374ed036309fce73f9db04c3054018a71912d46b
	https://git.kernel.org/stable/c/42049e65d338870e93732b0b80c6c41faf6aa781
	https://git.kernel.org/stable/c/d69c2ded95b17d51cc6632c7848cbd476381ecd6
	https://git.kernel.org/stable/c/a4bbab27c4bf69486f5846d44134eb31c37e9b22
	https://git.kernel.org/stable/c/54869daa6a437887614274f65298ba44a3fac63a
	https://git.kernel.org/stable/c/9cda812c76067c8a771eae43bb6943481cc7effc
	https://git.kernel.org/stable/c/68ed00a37d2d1c932ff7be40be4b90c4bec48c56
	https://git.kernel.org/stable/c/10ec8ca8ec1a2f04c4ed90897225231c58c124a7

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