CVE-2024-35957

/// Technical description

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

iommu/vt-d: Fix WARN_ON in iommu probe path

Commit 1a75cc710b95 ("iommu/vt-d: Use rbtree to track iommu probed

devices") adds all devices probed by the iommu driver in a rbtree

indexed by the source ID of each device. It assumes that each device

has a unique source ID. This assumption is incorrect and the VT-d

spec doesn't state this requirement either.

The reason for using a rbtree to track devices is to look up the device

with PCI bus and devfunc in the paths of handling ATS invalidation time

out error and the PRI I/O page faults. Both are PCI ATS feature related.

Only track the devices that have PCI ATS capabilities in the rbtree to

avoid unnecessary WARN_ON in the iommu probe path. Otherwise, on some

platforms below kernel splat will be displayed and the iommu probe results

in failure.

WARNING: CPU: 3 PID: 166 at drivers/iommu/intel/iommu.c:158 intel_iommu_probe_device+0x319/0xd90

Call Trace:

<TASK>

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/// 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