linux-cve-announce - CVE-2022-49610: KVM: VMX: Prevent RSB underflow before vmenter

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Message-ID: <2025022613-CVE-2022-49610-5628@gregkh>
Date: Wed, 26 Feb 2025 03:22:53 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49610: KVM: VMX: Prevent RSB underflow before vmenter

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

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

KVM: VMX: Prevent RSB underflow before vmenter

On VMX, there are some balanced returns between the time the guest's
SPEC_CTRL value is written, and the vmenter.

Balanced returns (matched by a preceding call) are usually ok, but it's
at least theoretically possible an NMI with a deep call stack could
empty the RSB before one of the returns.

For maximum paranoia, don't allow *any* returns (balanced or otherwise)
between the SPEC_CTRL write and the vmenter.

  [ bp: Fix 32-bit build. ]

The Linux kernel CVE team has assigned CVE-2022-49610 to this issue.


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

	Fixed in 5.18.14 with commit afd743f6dde87296c6f3414706964c491bb85862
	Fixed in 5.19 with commit 07853adc29a058c5fd143c14e5ac528448a72ed9

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-2022-49610
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/x86/kernel/asm-offsets.c
	arch/x86/kernel/cpu/bugs.c
	arch/x86/kvm/vmx/capabilities.h
	arch/x86/kvm/vmx/vmenter.S
	arch/x86/kvm/vmx/vmx.c
	arch/x86/kvm/vmx/vmx.h
	arch/x86/kvm/vmx/vmx_ops.h


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/afd743f6dde87296c6f3414706964c491bb85862
	https://git.kernel.org/stable/c/07853adc29a058c5fd143c14e5ac528448a72ed9