From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: ycao009@ucr.edu, netdev@vger.kernel.org, zhiyunq@cs.ucr.edu,
torvalds@linux-foundation.org, ycheng@google.com,
ncardwell@google.com
Subject: Re: [PATCH v2 net] tcp: make challenge acks less predictable
Date: Mon, 11 Jul 2016 13:34:00 -0700 (PDT) [thread overview]
Message-ID: <20160711.133400.1349480895641773377.davem@davemloft.net> (raw)
In-Reply-To: <1468137842.30694.58.camel@edumazet-glaptop3.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 10 Jul 2016 10:04:02 +0200
> From: Eric Dumazet <edumazet@google.com>
>
> Yue Cao claims that current host rate limiting of challenge ACKS
> (RFC 5961) could leak enough information to allow a patient attacker
> to hijack TCP sessions. He will soon provide details in an academic
> paper.
>
> This patch increases the default limit from 100 to 1000, and adds
> some randomization so that the attacker can no longer hijack
> sessions without spending a considerable amount of probes.
>
> Based on initial analysis and patch from Linus.
>
> Note that we also have per socket rate limiting, so it is tempting
> to remove the host limit in the future.
>
> v2: randomize the count of challenge acks per second, not the period.
>
> Fixes: 282f23c6ee34 ("tcp: implement RFC 5961 3.2")
> Reported-by: Yue Cao <ycao009@ucr.edu>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Applied and queued up for -stable, thanks Eric.
prev parent reply other threads:[~2016-07-11 20:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-08 16:33 [PATCH net] tcp: make challenge acks less predictable Eric Dumazet
[not found] ` <CAPzkZjz1R_T8q75LXLBc91j7YrngxdPc-o2Hpz+4YYyoWLantA@mail.gmail.com>
2016-07-09 8:16 ` Eric Dumazet
2016-07-10 8:04 ` [PATCH v2 " Eric Dumazet
2016-07-10 12:55 ` Neal Cardwell
2016-07-10 18:28 ` Yue Cao
2016-07-11 8:02 ` Eric Dumazet
2016-07-13 18:54 ` Yue Cao
2016-07-11 16:40 ` Yuchung Cheng
2016-07-11 20:34 ` David Miller [this message]
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