From: Florian Westphal <fw@strlen.de>
To: David Miller <davem@davemloft.net>
Cc: brouer@redhat.com, eric.dumazet@gmail.com,
hans.schillstrom@ericsson.com, subramanian.vijay@gmail.com,
dave.taht@gmail.com, netdev@vger.kernel.org,
ncardwell@google.com, therbert@google.com, mph@hoth.dk
Subject: Re: [PATCH v2 net-next] tcp: avoid tx starvation by SYNACK packets
Date: Wed, 27 Jun 2012 21:50:32 +0200 [thread overview]
Message-ID: <20120627195032.GI1269@breakpoint.cc> (raw)
In-Reply-To: <20120626.235423.588696200884989114.davem@davemloft.net>
David Miller <davem@davemloft.net> wrote:
> From: Jesper Dangaard Brouer <brouer@redhat.com>
> Date: Wed, 27 Jun 2012 08:32:13 +0200
>
> > Using it as default, might be "dangerous" and open an attack vector
> > on SYN cookies in Linux.
>
> If it's dangerous for syncookies then it's just as dangerous for
> the routing hash and the socket hashes where we use it already.
> Therefore, this sounds like a baseless claim to me.
I doubt using jhash is safe for syncookies.
There a several differences to other uses in kernel:
- all hash input except u32 cookie_secret[2] is known
- we transmit hash result (i.e, its visible to 3rd party)
- we do not re-seed the secret, ever
it should be quite easy to recompute cookie_secret[] from known syncookie
values?
next prev parent reply other threads:[~2012-06-27 19:50 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-31 21:56 [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Eric Dumazet
2012-05-31 23:03 ` David Miller
2012-06-01 4:48 ` Eric Dumazet
2012-06-01 17:46 ` David Miller
2012-06-01 7:00 ` [PATCH] tcp: do not create inetpeer on SYNACK message Eric Dumazet
2012-06-01 18:24 ` David Miller
2012-06-01 21:34 ` Hans Schillström
2012-06-02 6:56 ` Eric Dumazet
2012-06-01 7:36 ` [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Hans Schillstrom
2012-06-01 9:34 ` Eric Dumazet
2012-06-02 1:28 ` Dave Taht
2012-06-02 5:46 ` Eric Dumazet
2012-06-23 7:34 ` Vijay Subramanian
2012-06-23 8:42 ` [PATCH v2 " Eric Dumazet
2012-06-25 6:24 ` Hans Schillstrom
2012-06-25 22:43 ` David Miller
2012-06-26 4:51 ` Eric Dumazet
2012-06-26 4:55 ` David Miller
2012-06-26 5:34 ` Hans Schillstrom
2012-06-26 7:11 ` David Miller
2012-06-26 7:27 ` Hans Schillstrom
2012-06-26 17:02 ` Eric Dumazet
2012-06-27 5:23 ` Hans Schillstrom
2012-06-27 8:22 ` David Miller
2012-06-27 8:25 ` Jesper Dangaard Brouer
2012-06-27 8:30 ` Hans Schillstrom
2012-06-27 8:40 ` Eric Dumazet
2012-06-27 8:48 ` David Miller
2012-06-27 6:32 ` Jesper Dangaard Brouer
2012-06-27 6:54 ` David Miller
2012-06-27 7:24 ` Jesper Dangaard Brouer
2012-06-27 7:30 ` Eric Dumazet
2012-06-27 7:54 ` Jesper Dangaard Brouer
2012-06-27 8:02 ` Eric Dumazet
2012-06-27 8:21 ` Jesper Dangaard Brouer
2012-06-27 8:45 ` Eric Dumazet
2012-06-27 9:23 ` Jesper Dangaard Brouer
2012-06-27 8:13 ` David Miller
2012-06-27 19:50 ` Florian Westphal [this message]
2012-06-27 21:39 ` Eric Dumazet
2012-06-27 22:23 ` David Miller
2012-06-27 22:23 ` David Miller
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