netdev - Re: [PATCH net 3/3] net: sched: ife: check on metadata length

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Date:   Thu, 19 Apr 2018 08:37:36 +0300
From:   yotam gigi <yotam.gi@...il.com>
To:     Alexander Aring <aring@...atatu.com>
Cc:     Jamal Hadi Salim <jhs@...atatu.com>, davem@...emloft.net,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiří Pírko <jiri@...nulli.us>,
        Yuval Mintz <yuvalm@...lanox.com>, netdev@...r.kernel.org,
        kernel@...atatu.com
Subject: Re: [PATCH net 3/3] net: sched: ife: check on metadata length

On Thu, Apr 19, 2018 at 12:35 AM, Alexander Aring <aring@...atatu.com> wrote:
> This patch checks if sk buffer is available to dererence ife header. If
> not then NULL will returned to signal an malformed ife packet. This
> avoids to crashing the kernel from outside.
>
> Signed-off-by: Alexander Aring <aring@...atatu.com>

Reviewed-by: Yotam Gigi <yotam.gi@...il.com>

> ---
>  net/ife/ife.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/net/ife/ife.c b/net/ife/ife.c
> index 8632d2685efb..7c100034fbee 100644
> --- a/net/ife/ife.c
> +++ b/net/ife/ife.c
> @@ -70,6 +70,9 @@ void *ife_decode(struct sk_buff *skb, u16 *metalen)
>         u16 ifehdrln;
>
>         ifehdr = (struct ifeheadr *) (skb->data + skb->dev->hard_header_len);
> +       if (skb->len < skb->dev->hard_header_len + IFE_METAHDRLEN)
> +               return NULL;
> +
>         ifehdrln = ntohs(ifehdr->metalen);
>         total_pull = skb->dev->hard_header_len + ifehdrln;
>
> --
> 2.11.0
>