Bug 2492731 (CVE-2026-53171)

Summary: CVE-2026-53171 kernel: accel/ethosu: fix arithmetic issues in dma_length()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's accel/ethosu driver. The dma_length() function, responsible for calculating Direct Memory Access (DMA) region usage, contains several arithmetic issues. These issues, including potential underflows and overflows during calculations, can lead to an under-reporting of memory region sizes. This under-reporting can bypass crucial bounds validation checks, potentially allowing an attacker to access memory outside of its intended boundaries.
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Description OSIDB Bzimport 2026-06-25 10:02:47 UTC
In the Linux kernel, the following vulnerability has been resolved:

accel/ethosu: fix arithmetic issues in dma_length()

dma_length() derives DMA region usage from command stream values and
updates region_size[]:

    len = ((len + stride[0]) * size0 + stride[1]) * size1
    region_size[region] = max(..., len + dma->offset)

Several arithmetic issues can corrupt the derived region size:

- signed stride values may underflow when added to len
- intermediate multiplications may overflow
- len + dma->offset may overflow during region_size updates
- dma_length() error returns were not validated by the caller

region_size[] is later used by ethosu_job.c to validate command stream
accesses against GEM buffer sizes. Arithmetic wraparound can therefore
under-report region usage and bypass the bounds validation.

Fix by validating signed additions, using overflow helpers for
multiplications and offset updates, and propagating dma_length()
failures to the caller.