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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: David Miller <davem@davemloft.net>,
	kaber@trash.net, pablo@netfilter.org,
	netfilter-devel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH] net: check the length of the data before dereferencing it
Date: Mon, 02 Apr 2012 06:54:27 +0200	[thread overview]
Message-ID: <1333342467.2325.6739.camel@edumazet-glaptop> (raw)
In-Reply-To: <CABa6K_Hc7ZVVR6XvhEXKHNf_YNnrMNQLBTbxksvAJwAV9fer6w@mail.gmail.com>

On Mon, 2012-04-02 at 12:47 +0800, Changli Gao wrote:

> Got it. Thanks. FYI, the tcp options are copied to the stack before
> being parsed.
> 

What do you mean ?

code looks like :

const struct tcphdr *th = tcp_hdr(skb);
int length = (th->doff * 4) - sizeof(struct tcphdr);

ptr = (const unsigned char *)(th + 1);



Therefore ptr points somewhere in skb->head ... 




  reply	other threads:[~2012-04-02  4:54 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-02  3:10 [PATCH] net: check the length of the data before dereferencing it Changli Gao
2012-04-02  3:19 ` Eric Dumazet
2012-04-02  3:29   ` David Miller
2012-04-02  3:45     ` Changli Gao
2012-04-02  3:53       ` Eric Dumazet
2012-04-02  3:57         ` David Miller
2012-04-02  3:59           ` Eric Dumazet
2012-04-02  4:47         ` Changli Gao
2012-04-02  4:54           ` Eric Dumazet [this message]
2012-04-02  6:27             ` Changli Gao
2012-04-02  6:43               ` Eric Dumazet
2012-04-02  3:45     ` Eric Dumazet
2012-04-02  3:55       ` David Miller
2012-04-02  3:58         ` Eric Dumazet
2012-04-02  4:14           ` David Miller
2012-04-02  3:19 ` David Miller

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