linux-cve-announce - CVE-2023-54173: bpf: Disable preemption in bpf_event

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Message-ID: <2025123021-CVE-2023-54173-2f44@gregkh>
Date: Tue, 30 Dec 2025 13:09:41 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-54173: bpf: Disable preemption in bpf_event_output

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

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

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

bpf: Disable preemption in bpf_event_output

We received report [1] of kernel crash, which is caused by
using nesting protection without disabled preemption.

The bpf_event_output can be called by programs executed by
bpf_prog_run_array_cg function that disabled migration but
keeps preemption enabled.

This can cause task to be preempted by another one inside the
nesting protection and lead eventually to two tasks using same
perf_sample_data buffer and cause crashes like:

  BUG: kernel NULL pointer dereference, address: 0000000000000001
  #PF: supervisor instruction fetch in kernel mode
  #PF: error_code(0x0010) - not-present page
  ...
  ? perf_output_sample+0x12a/0x9a0
  ? finish_task_switch.isra.0+0x81/0x280
  ? perf_event_output+0x66/0xa0
  ? bpf_event_output+0x13a/0x190
  ? bpf_event_output_data+0x22/0x40
  ? bpf_prog_dfc84bbde731b257_cil_sock4_connect+0x40a/0xacb
  ? xa_load+0x87/0xe0
  ? __cgroup_bpf_run_filter_sock_addr+0xc1/0x1a0
  ? release_sock+0x3e/0x90
  ? sk_setsockopt+0x1a1/0x12f0
  ? udp_pre_connect+0x36/0x50
  ? inet_dgram_connect+0x93/0xa0
  ? __sys_connect+0xb4/0xe0
  ? udp_setsockopt+0x27/0x40
  ? __pfx_udp_push_pending_frames+0x10/0x10
  ? __sys_setsockopt+0xdf/0x1a0
  ? __x64_sys_connect+0xf/0x20
  ? do_syscall_64+0x3a/0x90
  ? entry_SYSCALL_64_after_hwframe+0x72/0xdc

Fixing this by disabling preemption in bpf_event_output.

[1] https://github.com/cilium/cilium/issues/26756

The Linux kernel CVE team has assigned CVE-2023-54173 to this issue.


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

	Issue introduced in 5.7 with commit 2a916f2f546ca1c1e3323e2a4269307f6d9890eb and fixed in 5.10.190 with commit 3048cb0dc0cc9dc74ed93690dffef00733bcad5b
	Issue introduced in 5.7 with commit 2a916f2f546ca1c1e3323e2a4269307f6d9890eb and fixed in 5.15.126 with commit c81bdf8f9f2b002d217c3d5357cdea9f2b82ff90
	Issue introduced in 5.7 with commit 2a916f2f546ca1c1e3323e2a4269307f6d9890eb and fixed in 6.1.45 with commit 36dd8ca330b76585640ed32255a3c99f901e1502
	Issue introduced in 5.7 with commit 2a916f2f546ca1c1e3323e2a4269307f6d9890eb and fixed in 6.4.10 with commit 063c9ce8e74e07bf94f99cd13146f42867875e8b
	Issue introduced in 5.7 with commit 2a916f2f546ca1c1e3323e2a4269307f6d9890eb and fixed in 6.5 with commit d62cc390c2e99ae267ffe4b8d7e2e08b6c758c32

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-2023-54173
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/trace/bpf_trace.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/3048cb0dc0cc9dc74ed93690dffef00733bcad5b
	https://git.kernel.org/stable/c/c81bdf8f9f2b002d217c3d5357cdea9f2b82ff90
	https://git.kernel.org/stable/c/36dd8ca330b76585640ed32255a3c99f901e1502
	https://git.kernel.org/stable/c/063c9ce8e74e07bf94f99cd13146f42867875e8b
	https://git.kernel.org/stable/c/d62cc390c2e99ae267ffe4b8d7e2e08b6c758c32