linux-cve-announce - CVE-2023-54181: bpf: Fix issue in verifying allow_ptr

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Message-ID: <2025123024-CVE-2023-54181-ef94@gregkh>
Date: Tue, 30 Dec 2025 13:09:49 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-54181: bpf: Fix issue in verifying allow_ptr_leaks

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

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

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

bpf: Fix issue in verifying allow_ptr_leaks

After we converted the capabilities of our networking-bpf program from
cap_sys_admin to cap_net_admin+cap_bpf, our networking-bpf program
failed to start. Because it failed the bpf verifier, and the error log
is "R3 pointer comparison prohibited".

A simple reproducer as follows,

SEC("cls-ingress")
int ingress(struct __sk_buff *skb)
{
	struct iphdr *iph = (void *)(long)skb->data + sizeof(struct ethhdr);

	if ((long)(iph + 1) > (long)skb->data_end)
		return TC_ACT_STOLEN;
	return TC_ACT_OK;
}

Per discussion with Yonghong and Alexei [1], comparison of two packet
pointers is not a pointer leak. This patch fixes it.

Our local kernel is 6.1.y and we expect this fix to be backported to
6.1.y, so stable is CCed.

[1]. https://lore.kernel.org/bpf/CAADnVQ+Nmspr7Si+pxWn8zkE7hX-7s93ugwC+94aXSy4uQ9vBg@mail.gmail.com/

The Linux kernel CVE team has assigned CVE-2023-54181 to this issue.


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

	Fixed in 6.1.53 with commit c96c67991aac6401b4c6996093bccb704bb2ea4b
	Fixed in 6.4.16 with commit 5927f0172d2809d8fc09c1ba667280b0387e9f73
	Fixed in 6.5.3 with commit acfdc8b77016c8e648aadc283177546c88083dd3
	Fixed in 6.6 with commit d75e30dddf73449bc2d10bb8e2f1a2c446bc67a2

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-2023-54181
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/verifier.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/c96c67991aac6401b4c6996093bccb704bb2ea4b
	https://git.kernel.org/stable/c/5927f0172d2809d8fc09c1ba667280b0387e9f73
	https://git.kernel.org/stable/c/acfdc8b77016c8e648aadc283177546c88083dd3
	https://git.kernel.org/stable/c/d75e30dddf73449bc2d10bb8e2f1a2c446bc67a2