Shift-Out-of-Bounds Vulnerability in Linux Kernel Affecting iommufd

CVE-2025-21724

Summary

A vulnerability in the Linux kernel's iommufd component could lead to undefined behavior due to a shift-out-of-bounds issue in the iova_bitmap_offset_to_index() function. When the variable bitmap->mapped.pgshift is greater than 31, the shift operation can overflow, resulting in unpredictable behavior. This was addressed by promoting the constant '1' to '1UL' to align with the operand type and prevent such shifts from occurring. Maintaining awareness of this vulnerability is crucial for users of the affected Linux kernel versions.

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