Description

In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: disallow non-power of two min_region_sz on damon_start() Commit d8f867fa0825 ("mm/damon: add damon_ctx->min_sz_region") introduced a bug that allows unaligned DAMON region address ranges. Commit c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz") fixed it, but only for damon_commit_ctx() use case. Still, DAMON sysfs interface can emit non-power of two min_region_sz via damon_start(). Fix the path by adding the is_power_of_2() check on damon_start(). The issue was discovered by sashiko [1].

References 3

• git.kernel.org https://git.kernel.org/stable/c/1de2db19a6028abe7d905875922faef5b873de67
• git.kernel.org https://git.kernel.org/stable/c/89b6226b6c2a4add3939f361653a47c212d6ab75
• git.kernel.org https://git.kernel.org/stable/c/95093e5cb4c5b50a5b1a4b79f2942b62744bd66a

Remediation