linux-cve-announce - CVE-2025-37948: arm64: bpf: Add BHB mitigation to the epilogue for cBPF programs

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Message-ID: <2025052000-CVE-2025-37948-2f8d@gregkh>
Date: Tue, 20 May 2025 18:02:02 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-37948: arm64: bpf: Add BHB mitigation to the epilogue for cBPF programs

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

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

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

arm64: bpf: Add BHB mitigation to the epilogue for cBPF programs

A malicious BPF program may manipulate the branch history to influence
what the hardware speculates will happen next.

On exit from a BPF program, emit the BHB mititgation sequence.

This is only applied for 'classic' cBPF programs that are loaded by
seccomp.

The Linux kernel CVE team has assigned CVE-2025-37948 to this issue.


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

	Fixed in 6.1.139 with commit 8fe5c37b0e08a97cf0210bb75970e945aaaeebab
	Fixed in 6.6.91 with commit 42a20cf51011788f04cf2adbcd7681f02bdb6c27
	Fixed in 6.12.29 with commit 38c345fd54afd9d6ed8d3fcddf3f6ea23887bf78
	Fixed in 6.14.7 with commit 852b8ae934b5cbdc62496fa56ce9969aa2edda7f
	Fixed in 6.15-rc7 with commit 0dfefc2ea2f29ced2416017d7e5b1253a54c2735

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-2025-37948
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:
	arch/arm64/include/asm/spectre.h
	arch/arm64/kernel/proton-pack.c
	arch/arm64/net/bpf_jit_comp.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/8fe5c37b0e08a97cf0210bb75970e945aaaeebab
	https://git.kernel.org/stable/c/42a20cf51011788f04cf2adbcd7681f02bdb6c27
	https://git.kernel.org/stable/c/38c345fd54afd9d6ed8d3fcddf3f6ea23887bf78
	https://git.kernel.org/stable/c/852b8ae934b5cbdc62496fa56ce9969aa2edda7f
	https://git.kernel.org/stable/c/0dfefc2ea2f29ced2416017d7e5b1253a54c2735