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From: Florian Westphal <fw at strlen.de>
To: mptcp at lists.01.org
Subject: [MPTCP] Re: [syzkaller] KASAN: use-after-free Write in __lock_sock
Date: Tue, 04 Feb 2020 11:46:17 +0100	[thread overview]
Message-ID: <20200204104617.GF15904@breakpoint.cc> (raw)
In-Reply-To: 5b235b4f2636c7621be6a8526e8b6f5cfb7852de.camel@redhat.com

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Paolo Abeni <pabeni(a)redhat.com> wrote:
> On Tue, 2020-02-04 at 00:59 +0100, Florian Westphal wrote:
> > AFAICS we need to revert to a state we had very early on:
> > proxy tcp fallback case everywhere: msk is left alone and
> > sendmsg/recvmsg and so on invoke the tcp versions on the (only) ssk.
> 
> That is unfortunated, I liked the fact that a fallback socket got the
> same performances of a plain TCP socket (could encourage MPTCP adoption
> - not sure that is good thing, anyway ;)

Heh.

> On the plus side, __mptcp_tcp_fallback() should be already hooked in
> every place where we need special/single subflow handling. Should be
> just a matter of simplify __mptcp_tcp_fallback() to just return the
> subflow sk.

Yes, I can confirm that I don't get a crash when i dumb-down the
fallback to always proxy.

> I guess/hope we can still call mptcp_subflow_tcp_fallback() - so that
> at least we get no overhead in the BH processing for the fall-back sk.

Right, I will have a look to see if we can repair it somehow.

If we have to go with always-proxy we will still have the server-side
mostly covered hwoever, mptcp accept will still return plain tcp sk for
non-mptcp syn case.

             reply	other threads:[~2020-02-04 10:46 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-04 10:46 Florian Westphal [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-02-04 12:34 [MPTCP] Re: [syzkaller] KASAN: use-after-free Write in __lock_sock Matthieu Baerts
2020-02-04  9:12 Paolo Abeni
2020-02-04  6:55 Florian Westphal
2020-02-04  0:24 Christoph Paasch
2020-02-03 23:59 Florian Westphal
2020-02-03 20:52 Christoph Paasch
2020-02-03 10:49 Paolo Abeni
2020-02-01  1:12 Christoph Paasch

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