From: Florian Westphal <fw@strlen.de>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Florian Westphal <fw@strlen.de>,
Dmitry Vyukov <dvyukov@google.com>,
"David S. Miller" <davem@davemloft.net>,
Herbert Xu <herbert@gondor.apana.org.au>,
Thomas Graf <tgraf@suug.ch>,
Ken-ichirou MATSUZAWA <chamaken@gmail.com>,
Eric Dumazet <edumazet@google.com>,
David Herrmann <dh.herrmann@gmail.com>,
Nicolas Dichtel <nicolas.dichtel@6wind.com>,
netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
syzkaller <syzkaller@googlegroups.com>,
Kostya Serebryany <kcc@google.com>,
Alexander Potapenko <glider@google.com>,
Sasha Levin <sasha.levin@oracle.com>,
netfilter-devel@vger.kernel.org
Subject: Re: net: GPF in netlink_getsockbyportid
Date: Sun, 24 Jan 2016 01:11:03 +0100 [thread overview]
Message-ID: <20160124001103.GA2748@breakpoint.cc> (raw)
In-Reply-To: <56A3DCF7.7000404@iogearbox.net>
Daniel Borkmann <daniel@iogearbox.net> wrote:
> On 01/23/2016 08:25 PM, Florian Westphal wrote:
> >Dmitry Vyukov <dvyukov@google.com> wrote:
> >
> >[ CC nf-devel, not sure if its nfnetlink fault or NETLINK_MMAP ]
> >
> >>The following program causes GPF in netlink_getsockbyportid:
[..]
> >CONFIG_NETLINK_MMAP and nfnetlink batching strike in unison :-/
> >
> >root cause is in nfnetlink_rcv_batch():
> >
> >296 replay:
> >297 status = 0;
> >298
> >299 skb = netlink_skb_clone(oskb, GFP_KERNEL);
> >
> >The clone op doesn't copy oskb->sk, so we oops in
> >__netlink_alloc_skb -> netlink_getsockbyportid() when nfnetlink_rcv_batch
> >tries to send netlink ack.
>
> If indeed oskb is the mmap'ed netlink skb, then it's not even allowed
> to call into skb_clone()
Right, but in this case there is no mmap'd netlink sk involved -- we
crash when we try to look up dst netlink socket to see if there is an
mmap'd ring attached.
[ and that code isn't there with CONFIG_NETLINK_MMAP=n ].
next prev parent reply other threads:[~2016-01-24 0:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-23 18:24 net: GPF in netlink_getsockbyportid Dmitry Vyukov
2016-01-23 19:25 ` Florian Westphal
2016-01-23 20:05 ` Daniel Borkmann
2016-01-24 0:11 ` Florian Westphal [this message]
2016-01-25 10:03 ` Herbert Xu
2016-01-25 10:17 ` Pablo Neira Ayuso
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