Bug 2348649 (CVE-2025-21724)

Summary: CVE-2025-21724 kernel: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-02-27 03:06:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index()

Resolve a UBSAN shift-out-of-bounds issue in iova_bitmap_offset_to_index()
where shifting the constant "1" (of type int) by bitmap->mapped.pgshift
(an unsigned long value) could result in undefined behavior.

The constant "1" defaults to a 32-bit "int", and when "pgshift" exceeds
31 (e.g., pgshift = 63) the shift operation overflows, as the result
cannot be represented in a 32-bit type.

To resolve this, the constant is updated to "1UL", promoting it to an
unsigned long type to match the operand's type.
Comment 1 Mauro Matteo Cascella 2025-02-27 19:44:27 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022647-CVE-2025-21724-f4b1@gregkh/T