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.