linux-cve-announce - CVE-2022-49568: KVM: Don't null dereference ops->destroy

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Message-ID: <2025022606-CVE-2022-49568-e2f5@gregkh>
Date: Wed, 26 Feb 2025 03:22:11 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49568: KVM: Don't null dereference ops->destroy

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

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

KVM: Don't null dereference ops->destroy

A KVM device cleanup happens in either of two callbacks:
1) destroy() which is called when the VM is being destroyed;
2) release() which is called when a device fd is closed.

Most KVM devices use 1) but Book3s's interrupt controller KVM devices
(XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during
the machine execution. The error handling in kvm_ioctl_create_device()
assumes destroy() is always defined which leads to NULL dereference as
discovered by Syzkaller.

This adds a checks for destroy!=NULL and adds a missing release().

This is not changing kvm_destroy_devices() as devices with defined
release() should have been removed from the KVM devices list by then.

The Linux kernel CVE team has assigned CVE-2022-49568 to this issue.

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

	Fixed in 5.4.210 with commit 170465715a60cbb7876e6b961b21bd3225469da8
	Fixed in 5.10.134 with commit 3616776bc51cd3262bb1be60cc01c72e0a1959cf
	Fixed in 5.15.58 with commit e91665fbbf3ccb268b268a7d71a6513538d813ac
	Fixed in 5.18.15 with commit d4a5a79b780891c5cbdfdc6124d46fdf8d13dba1
	Fixed in 5.19 with commit e8bc2427018826e02add7b0ed0fc625a60390ae5

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-2022-49568
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:
	virt/kvm/kvm_main.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/170465715a60cbb7876e6b961b21bd3225469da8
	https://git.kernel.org/stable/c/3616776bc51cd3262bb1be60cc01c72e0a1959cf
	https://git.kernel.org/stable/c/e91665fbbf3ccb268b268a7d71a6513538d813ac
	https://git.kernel.org/stable/c/d4a5a79b780891c5cbdfdc6124d46fdf8d13dba1
	https://git.kernel.org/stable/c/e8bc2427018826e02add7b0ed0fc625a60390ae5