Re: [PATCH][next] netdevsim: fix sa_idx out of bounds check

[Shannon Nelson]

On 6/30/2018 1:39 PM, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Currently if sa_idx is equal to NSIM_IPSEC_MAX_SA_COUNT then
> an out-of-bounds read on ipsec->sa will occur. Fix the
> incorrect bounds check by using >= rather than >.
>
> Detected by CoverityScan, CID#1470226 ("Out-of-bounds-read")
>
> Fixes: 7699353da875 ("netdevsim: add ipsec offload testing")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>   drivers/net/netdevsim/ipsec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/netdevsim/ipsec.c b/drivers/net/netdevsim/ipsec.c
> index ceff544510b9..2dcf6cc269d0 100644
> --- a/drivers/net/netdevsim/ipsec.c
> +++ b/drivers/net/netdevsim/ipsec.c
> @@ -249,7 +249,7 @@ bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
>   	}
>   
>   	sa_idx = xs->xso.offload_handle & ~NSIM_IPSEC_VALID;
> -	if (unlikely(sa_idx > NSIM_IPSEC_MAX_SA_COUNT)) {
> +	if (unlikely(sa_idx >= NSIM_IPSEC_MAX_SA_COUNT)) {
>   		netdev_err(ns->netdev, "bad sa_idx=%d max=%d\n",
>   			   sa_idx, NSIM_IPSEC_MAX_SA_COUNT);
>   		return false;

Good catch - thanks!

Acked-by: Shannon Nelson <shannon.nelson@xxxxxxxxxx>