Bug 2393196 (CVE-2025-38688)

Summary: CVE-2025-38688 kernel: iommufd: Prevent ALIGN() overflow
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-09-04 16:04:19 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iommufd: Prevent ALIGN() overflow

When allocating IOVA the candidate range gets aligned to the target
alignment. If the range is close to ULONG_MAX then the ALIGN() can
wrap resulting in a corrupted iova.

Open code the ALIGN() using get_add_overflow() to prevent this.
This simplifies the checks as we don't need to check for length earlier
either.

Consolidate the two copies of this code under a single helper.

This bug would allow userspace to create a mapping that overlaps with some
other mapping or a reserved range.
Comment 1 Jon Moroney 2025-09-04 17:31:15 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025090448-CVE-2025-38688-6e94@gregkh/T