Subject: Re: [3/3] gso: Handle malicious GRO packets without crashing

From: Sergei Shtylyov <[email-masked]>
Date: Thu, 07 Nov 2013 22:13:29 +0300

Hello.

On 11/07/2013 10:08 AM, Herbert Xu wrote:

> As virtio_net can now generate GRO frag_list packets without
> sufficient verification, we need to handle malicious GRO packets
> thrown at us.

> This patch converts to affected BUG_ONs in skb_segment to rate-
> limited warnings.

> Signed-off-by: Herbert Xu <[email-masked]>

> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index bcc3f1c..fb1106d 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -2881,7 +2881,15 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
>   			while (tail->next)
>   				tail = tail->next;
>
> -			BUG_ON(fskb && tail->len != len + doffset);
> +			if (fskb && tail->len != len + doffset) {
> +				net_warn_ratelimited(
> +					"skb_segment: "
> +					"illegal GSO fragment: %u %u\n",

    Don't break up the message -- chekpatch.pl should allow that...

> @@ -2929,7 +2937,15 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
>   		if (pos < offset + len) {
>   			struct sk_buff *fskb2 = fskb;
>
> -			BUG_ON(pos + fskb->len != offset + len);
> +			if (pos + fskb->len != offset + len) {
> +				net_warn_ratelimited(
> +					"skb_segment: "
> +					"illegal GSO trailer: %u %u\n",

    Same here.

WBR, Sergei