Re: [PATCH 2/2] ehea: Receive SKB Aggregation

From: Stephen Hemminger
Date: Thu May 31 2007 - 12:48:54 EST



>
>
> +static int try_get_ip_tcp_hdr(struct ehea_cqe *cqe, struct sk_buff *skb,
> + struct iphdr **iph, struct tcphdr **tcph)
> +{
> + int ip_len;
> +
> + /* non tcp/udp packets */
> + if (!cqe->header_length)
> + return -1;
> +
> + /* non tcp packet */
> + *iph = (struct iphdr *)(skb->data);

Why the indirection, copying of headers..

> + if ((*iph)->protocol != IPPROTO_TCP)
> + return -1;
> +
> + ip_len = (u8)((*iph)->ihl);
> + ip_len <<= 2;
> + *tcph = (struct tcphdr *)(((u64)*iph) + ip_len);
> +
> + return 0;
> +}
> +
>

This code seems to be duplicating a lot (but not all) of the TCP/IP
input path validation checks. This is a security problem if nothing else...

Also, how do you prevent DoS attacks from hostile TCP senders that send
huge number of back to back frames?

--
Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx>
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