Re: [PATCH ipvs-next] ipvs: ip_vs_sh: ip_vs_sh_get_port: check skb_header_pointer for NULL

[Julian Anastasov <ja@xxxxxx>]

        Hello,

On Tue, 6 Aug 2013, Daniel Borkmann wrote:

> skb_header_pointer could return NULL, so check for it as we do it
> everywhere else in ipvs code. This fixes a coverity warning.
> 
> Signed-off-by: Daniel Borkmann <dborkman@xxxxxxxxxx>
> ---
>  I'd consider the case of NULL quite unlikely, therefore ipvs-next should
>  be sufficient.

        Agreed, to avoid confusion...

Acked-by: Julian Anastasov <ja@xxxxxx>

        At the time when SH patch was submitted I ignored
it as problem because this code is part of the scheduling
lookup and we already passed such skb_header_pointer()
checks at top of tcp_conn_schedule().

>  net/netfilter/ipvs/ip_vs_sh.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_sh.c b/net/netfilter/ipvs/ip_vs_sh.c
> index f16c027..3588fae 100644
> --- a/net/netfilter/ipvs/ip_vs_sh.c
> +++ b/net/netfilter/ipvs/ip_vs_sh.c
> @@ -269,14 +269,20 @@ ip_vs_sh_get_port(const struct sk_buff *skb, struct 
> ip_vs_iphdr *iph)
>       switch (iph->protocol) {
>       case IPPROTO_TCP:
>               th = skb_header_pointer(skb, iph->len, sizeof(_tcph), &_tcph);
> +             if (unlikely(th == NULL))
> +                     return 0;
>               port = th->source;
>               break;
>       case IPPROTO_UDP:
>               uh = skb_header_pointer(skb, iph->len, sizeof(_udph), &_udph);
> +             if (unlikely(uh == NULL))
> +                     return 0;
>               port = uh->source;
>               break;
>       case IPPROTO_SCTP:
>               sh = skb_header_pointer(skb, iph->len, sizeof(_sctph), &_sctph);
> +             if (unlikely(sh == NULL))
> +                     return 0;
>               port = sh->source;
>               break;
>       default:
> -- 
> 1.7.11.7

Regards

--
Julian Anastasov <ja@xxxxxx>
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