Re: [PATCH] f2fs: prevent possible int overflow in dir_block_index()

On 2024/7/25 1:05, Nikita Zhandarovich wrote:

The result of multiplication between values derived from functions dir_buckets() and bucket_blocks() *could* technically reach 2^30 * 2^2 = 2^32.

While unlikely to happen, it is prudent to ensure that it will not lead to integer overflow. Thus, use mul_u32_u32() as it's more appropriate to mitigate the issue.

Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE.

Fixes: 3843154598a0 ("f2fs: introduce large directory support") Cc: stable@vger.kernel.org Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru

Reviewed-by: Chao Yu chao@kernel.org

Thanks,