CVE-2024-35843 Affecting kernel-rt package, versions *

Note: Versions mentioned in the description apply only to the upstream kernel-rt package and not the kernel-rt package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

iommu/vt-d: Use device rbtree in iopf reporting path

The existing I/O page fault handler currently locates the PCI device by calling pci_get_domain_bus_and_slot(). This function searches the list of all PCI devices until the desired device is found. To improve lookup efficiency, replace it with device_rbtree_find() to search the device within the probed device rbtree.

The I/O page fault is initiated by the device, which does not have any synchronization mechanism with the software to ensure that the device stays in the probed device tree. Theoretically, a device could be released by the IOMMU subsystem after device_rbtree_find() and before iopf_get_dev_fault_param(), which would cause a use-after-free problem.

Add a mutex to synchronize the I/O page fault reporting path and the IOMMU release device path. This lock doesn't introduce any performance overhead, as the conflict between I/O page fault reporting and device releasing is very rare.

• https://access.redhat.com/security/cve/CVE-2024-35843
• https://git.kernel.org/stable/c/3d39238991e745c5df85785604f037f35d9d1b15
• https://git.kernel.org/stable/c/def054b01a867822254e1dda13d587f5c7a99e2a