CVE-2024-56668

/// Technical description

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

iommu/vt-d: Fix qi_batch NULL pointer with nested parent domain

The qi_batch is allocated when assigning cache tag for a domain. While

for nested parent domain, it is missed. Hence, when trying to map pages

to the nested parent, NULL dereference occurred. Also, there is potential

memleak since there is no lock around domain->qi_batch allocation.

To solve it, add a helper for qi_batch allocation, and call it in both

the __cache_tag_assign_domain() and __cache_tag_assign_parent_domain().

BUG: kernel NULL pointer dereference, address: 0000000000000200

#PF: supervisor read access in kernel mode

#PF: error_code(0x0000) - not-present page

PGD 8104795067 P4D 0

Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI

CPU: 223 UID: 0 PID: 4357 Comm: qemu-system-x86 Not tainted 6.13.0-rc1-00028-g4b50c3c3b998-dirty #2632

Call Trace:

? __die+0x24/0x70

? page_fault_oops+0x80/0x150

? do_user_addr_fault+0x63/0x7b0

? exc_

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References