On Thu, Oct 18, 2018 at 10:02:58AM +0200, Gustavo A. R. Silva wrote:
> Cast *max_num_sg* to u64 in order to give the compiler complete
> information about the proper arithmetic to use.
>
> Notice that such variable is used in a context that expects an
> expression of type u64 (64 bits, unsigned) and the following
> expression is currently being evaluated using 32-bit
> arithmetic:
>
> length = max_num_sg * page_size;
>
> Addresses-Coverity-ID: 1474517 ("Unintentional integer overflow")
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> drivers/infiniband/hw/hns/hns_roce_mr.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c b/drivers/infiniband/hw/hns/hns_roce_mr.c
> index 521ad2a..d479d5e 100644
> +++ b/drivers/infiniband/hw/hns/hns_roce_mr.c
> @@ -1219,7 +1219,7 @@ struct ib_mr *hns_roce_alloc_mr(struct ib_pd *pd, enum ib_mr_type mr_type,
> int ret;
>
> page_size = 1 << (hr_dev->caps.pbl_buf_pg_sz + PAGE_SHIFT);
> - length = max_num_sg * page_size;
> + length = (u64)max_num_sg * page_size;
This should be done with check_mul_overflow() which will also force
the input types to the correct thing.
alloc_mr is callable from userspace so the potential overflow here
should not be ignored.
Jason
