Re: [PATCH v2 1/4] net: tun: fix tun_xdp_one() for IFF_TUN mode

[David Woodhouse <dwmw2@infradead.org>]

[-- Attachment #1: Type: text/plain, Size: 1010 bytes --]

On Wed, 2021-06-23 at 14:52 +0100, David Woodhouse wrote:
> @@ -2343,6 +2351,17 @@ static int tun_xdp_one(struct tun_struct *tun,
>         if (tun->flags & IFF_VNET_HDR)
>                 gso = &hdr->gso;
>  
> +       if (!(tun->flags & IFF_NO_PI)) {
> +               struct tun_pi *pi = xdp->data;
> +               if (datasize < sizeof(*pi)) {
> +                       atomic_long_inc(&tun->rx_frame_errors);
> +                       return  -EINVAL;
> +               }
> +               proto = pi->proto;
> +               reservelen += sizeof(*pi);
> +               datasize -= sizeof(*pi);
> +       }
> +
>         xdp_prog = rcu_dereference(tun->xdp_prog);
>         if (xdp_prog) {
>                 if (gso && gso->gso_type) {

Joy... that's wrong because when tun does both the PI and the vnet
headers, the PI header comes *first*. When tun does only PI and vhost
does the vnet headers, they come in the other order.

Will fix (and adjust the test cases to cope).


[-- Attachment #2: smime.p7s --]
[-- Type: application/x-pkcs7-signature, Size: 5174 bytes --]