netdev - RE: TCP_COOKIE_TRANSACTIONS synack data

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Date:	Mon, 8 Mar 2010 18:33:28 +0200
From:	Penttilä Mika <mika.penttila@...nos.com>
To:	Eric Dumazet <eric.dumazet@...il.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 ?
> 

I'm not planning to provide a patch at least very soon so I think someone else can provide a quicker fix.


> Thanks
> 
>