CVE-2024-53071 drm/panthor: Be stricter about IO mapping flags

What is CVE-2024-53071?

CVE-2024-53071 is a medium-severity vulnerability in Linux kernel, published on 19 Nov 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

drm/panthor: Be stricter about IO mapping flags

The current panthor_device_mmap_io() implementation has two issues:

1. For mapping DRM_PANTHOR_USER_FLUSH_ID_MMIO_OFFSET, panthor_device_mmap_io() bails if VM_WRITE is set, but does not clear VM_MAYWRITE. That means userspace can use mprotect() to make the mapping writable later on. This is a classic Linux driver gotcha. I don't think this actually has any impact in practice: When the GPU is powered, writes to the FLUSH_ID seem to be ignored; and when the GPU is not powered, the dummy_latest_flush page provided by the driver is deliberately designed to not do any flushes, so the only thing writing to the dummy_latest_flush could achieve would be to make *more* flushes happen.

2. panthor_device_mmap_io() does not block MAP_PRIVATE mappings (which are mappings without the VM_SHARED flag). MAP_PRIVATE in combination with VM_MAYWRITE indicates that the VMA has copy-on-write semantics, which for VM_PFNMAP are semi-supported but fairly cursed. In particular, in such a mapping, the driver can only install PTEs during mmap() by calling remap_pfn_range() (because remap_pfn_range() wants to **store the physical address of the mapped physical memory into the vm_pgoff of the VMA**); installing PTEs later on with a fault handler (as panthor does) is not supported in private mappings, and so if you try to fault in such a mapping, vmf_insert_pfn_prot() splats when it hits a BUG() check.

Fix it by clearing the VM_MAYWRITE flag (userspace writing to the FLUSH_ID doesn't make sense) and requiring VM_SHARED (copy-on-write semantics for the FLUSH_ID don't make sense).

Reproducers for both scenarios are in the notes of my patch on the mailing list; I tested that these bugs exist on a Rock 5B machine.

Note that I only compile-tested the patch, I haven't tested it; I don't have a working kernel build setup for the test machine yet. Please test it before applying it.

Which versions are affected by CVE-2024-53071?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-53071?

Apply the vendor's patch.

Is CVE-2024-53071 being exploited?

There is no known exploitation of CVE-2024-53071 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2024-53071, DEBIAN-CVE-2024-53071, GHSA-42c7-w7r7-3v3m, UBUNTU-CVE-2024-53071.