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From: Hannes Frederic Sowa <hannes@stressinduktion•org>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail•com>,
	Cong Wang <xiyou.wangcong@gmail•com>,
	netdev@vger•kernel.org, Eric Dumazet <edumazet@google•com>,
	Yuchung Cheng <ycheng@google•com>,
	Neal Cardwell <ncardwell@google•com>,
	Martin KaFai Lau <kafai@fb•com>,
	Brendan Gregg <brendan.d.gregg@gmail•com>,
	Song Liu <songliubraving@fb•com>
Subject: Re: [Patch net-next] tcp: add a tracepoint for tcp_retransmit_skb()
Date: Thu, 12 Oct 2017 11:39:57 +0200	[thread overview]
Message-ID: <87a80wd7rm.fsf@stressinduktion.org> (raw)
In-Reply-To: <1507747095.31614.26.camel@edumazet-glaptop3.roam.corp.google.com> (Eric Dumazet's message of "Wed, 11 Oct 2017 11:38:15 -0700")

Eric Dumazet <eric.dumazet@gmail•com> writes:

[...]

> Since this sock_gen_cookie() is lock-free and IRQ ready, it should be
> not be a problem to pretend it works with a const socket.
>
> I am a bit unsure about revealing in socket cookie a precise count of
> sockets created on a netns. Some attackers might use this in a side
> channel attack.

That is true. We expose this information already via the inode number
allocator for sockets. It is a bit imprecise because of using CPU
batches.

      reply	other threads:[~2017-10-12  9:40 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-10  5:35 [Patch net-next] tcp: add a tracepoint for tcp_retransmit_skb() Cong Wang
2017-10-10 11:21 ` Eric Dumazet
2017-10-10 17:16   ` Cong Wang
2017-10-10 17:38 ` Alexei Starovoitov
2017-10-10 21:37   ` Cong Wang
2017-10-11  2:53     ` Alexei Starovoitov
2017-10-10 21:58   ` Hannes Frederic Sowa
2017-10-11  2:56     ` Alexei Starovoitov
2017-10-11 13:31       ` Eric Dumazet
2017-10-11 18:21         ` Alexei Starovoitov
2017-10-11 18:38           ` Eric Dumazet
2017-10-12  9:39             ` Hannes Frederic Sowa [this message]

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