Re: [PATCH][net-next] sfc: fix an off-by-one compare on an array size

[Edward Cree]

On 31/01/17 16:30, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> encap_type should be checked to see if it is greater or equal to
> the size of array map to fix an off-by-one array size check. This
> fixes an array overrun read as detected by static analysis by
> CoverityScan, CID#1398883 ("Out-of-bounds-read")
>
> Fixes: 9b41080125176841e ("sfc: insert catch-all filters for encapsulated traffic")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Good catch.

Acked-by: Edward Cree <ecree@xxxxxxxxxxxxxx>
> ---
>  drivers/net/ethernet/sfc/ef10.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
> index 8bec938..0475f18 100644
> --- a/drivers/net/ethernet/sfc/ef10.c
> +++ b/drivers/net/ethernet/sfc/ef10.c
> @@ -5080,7 +5080,7 @@ static int efx_ef10_filter_insert_def(struct efx_nic *efx,
>  
>  		/* quick bounds check (BCAST result impossible) */
>  		BUILD_BUG_ON(EFX_EF10_BCAST != 0);
> -		if (encap_type > ARRAY_SIZE(map) || map[encap_type] == 0) {
> +		if (encap_type >= ARRAY_SIZE(map) || map[encap_type] == 0) {
>  			WARN_ON(1);
>  			return -EINVAL;
>  		}