Subject: CVE-2024-27079: iommu/vt-d: Fix NULL domain on device release

From: Greg Kroah-Hartman <[email-masked]>

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

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

iommu/vt-d: Fix NULL domain on device release

In the kdump kernel, the IOMMU operates in deferred_attach mode. In this
mode, info->domain may not yet be assigned by the time the release_device
function is called. It leads to the following crash in the crash kernel:

    BUG: kernel NULL pointer dereference, address: 000000000000003c
    ...
    RIP: 0010:do_raw_spin_lock+0xa/0xa0
    ...
    _raw_spin_lock_irqsave+0x1b/0x30
    intel_iommu_release_device+0x96/0x170
    iommu_deinit_device+0x39/0xf0
    __iommu_group_remove_device+0xa0/0xd0
    iommu_bus_notifier+0x55/0xb0
    notifier_call_chain+0x5a/0xd0
    blocking_notifier_call_chain+0x41/0x60
    bus_notify+0x34/0x50
    device_del+0x269/0x3d0
    pci_remove_bus_device+0x77/0x100
    p2sb_bar+0xae/0x1d0
    ...
    i801_probe+0x423/0x740

Use the release_domain mechanism to fix it. The scalable mode context
entry which is not part of release domain should be cleared in
release_device().

The Linux kernel CVE team has assigned CVE-2024-27079 to this issue.

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

	Issue introduced in 5.18 with commit 586081d3f6b1 and fixed in 6.8.2 with commit 333fe8696848
	Issue introduced in 5.18 with commit 586081d3f6b1 and fixed in 6.9 with commit 81e921fd3216

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-2024-27079
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:
	drivers/iommu/intel/iommu.c
	drivers/iommu/intel/pasid.c
	drivers/iommu/intel/pasid.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/333fe86968482ca701c609af590003bcea450e8f
	https://git.kernel.org/stable/c/81e921fd321614c2ad8ac333b041aae1da7a1c6d