CVE-2023-52659 x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type

What is CVE-2023-52659?

CVE-2023-52659 is a medium-severity vulnerability in Linux kernel, published on 17 May 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:

x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type

On 64-bit platforms, the pfn_to_kaddr() macro requires that the input value is 64 bits in order to ensure that valid address bits don't get lost when shifting that input by PAGE_SHIFT to calculate the physical address to provide a virtual address for.

One such example is in pvalidate_pages() (used by SEV-SNP guests), where the GFN in the struct used for page-state change requests is a 40-bit bit-field, so attempts to pass this GFN field directly into pfn_to_kaddr() ends up causing guest crashes when dealing with addresses above the 1TB range due to the above.

Fix this issue with SEV-SNP guests, as well as any similar cases that might cause issues in current/future code, by using an inline function, instead of a macro, so that the input is implicitly cast to the expected 64-bit input type prior to performing the shift operation.

While it might be argued that the issue is on the caller side, other archs/macros have taken similar approaches to deal with instances like this, such as ARM explicitly casting the input to phys_addr_t:

e48866647b48 ("ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()")

A C inline function is even better though.

[ mingo: Refined the changelog some more & added __always_inline. ]

Which versions are affected by CVE-2023-52659?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2023-52659?

Apply the vendor's patch.

Is CVE-2023-52659 being exploited?

There is no known exploitation of CVE-2023-52659 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-2023-52659, DEBIAN-CVE-2023-52659, GHSA-jpp4-rwwf-g5qm, UBUNTU-CVE-2023-52659.