netdev - Re: TCP_COOKIE_TRANSACTIONS synack data

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Message-ID: <1268064070.6148.104.camel@edumazet-laptop>
Date:	Mon, 08 Mar 2010 17:01:10 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Penttilä Mika <mika.penttila@...nos.com>
Cc:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	William Allen Simpson <william.allen.simpson@...il.com>
Subject: Re: TCP_COOKIE_TRANSACTIONS synack data

Le lundi 08 mars 2010 à 16:27 +0200, Penttilä Mika a écrit :
> The TCP_COOKIE_TRANSACTIONS synack data seems pretty unsafe atm. 
> >From tcp_make_synack():
> 
> 
> 	u8 *buf = skb_put(skb, cvp->s_data_desired);
> 
> 	/* copy data directly from the listening socket. */
>     	memcpy(buf, cvp->s_data_payload, cvp->s_data_desired);
> 
> 
> The skb here is allocated for MAX_TCP_HEADER + 15 and synack data could be as long as TCP_MSS_DEFAULT, panic():ing at the skb_put().
> 

Indeed, since start of december 2009.

Do you plan to provide a patch do you prefer someone else take care of
it ?

Thanks


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