From: Florian Westphal <fw@strlen.de>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Herbert Xu <herbert@gondor.apana.org.au>,
Thomas Graf <tgraf@suug.ch>,
Daniel Borkmann <daniel@iogearbox.net>,
Ken-ichirou MATSUZAWA <chamaken@gmail.com>,
Eric Dumazet <edumazet@google.com>,
David Herrmann <dh.herrmann@gmail.com>,
Nicolas Dichtel <nicolas.dichtel@6wind.com>,
Florian Westphal <fw@strlen.de>, 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: Sat, 23 Jan 2016 20:25:02 +0100 [thread overview]
Message-ID: <20160123192502.GB17729@breakpoint.cc> (raw)
In-Reply-To: <CACT4Y+Zmwr0VbfB5RAoLTCJJAF7epZWbbMkHxtXUwvF3tXbrgQ@mail.gmail.com>
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:
>
> // autogenerated by syzkaller (http://github.com/google/syzkaller)
> #include <pthread.h>
> #include <stdint.h>
> #include <string.h>
> #include <sys/syscall.h>
> #include <unistd.h>
>
> int main()
> {
> syscall(SYS_mmap, 0x20000000ul, 0xe65000ul, 0x3ul, 0x32ul,
> 0xfffffffffffffffful, 0x0ul);
> int fd = syscall(SYS_socket, 0x10ul, 0x803ul, 0xcul, 0, 0, 0);
> *(uint32_t*)0x20e64000 = (uint32_t)0x28;
> *(uint32_t*)0x20e64004 = (uint32_t)0x10;
> *(uint64_t*)0x20e64008 = (uint64_t)0x0;
> *(uint64_t*)0x20e64010 = (uint64_t)0x3;
> *(uint64_t*)0x20e64018 = (uint64_t)0xfff;
> *(uint16_t*)0x20e64020 = (uint16_t)0x5;
> syscall(SYS_write, fd, 0x20e64000ul, 0x28ul, 0, 0, 0);
> return 0;
> }
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.
next prev parent reply other threads:[~2016-01-23 19:25 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 [this message]
2016-01-23 20:05 ` Daniel Borkmann
2016-01-24 0:11 ` Florian Westphal
2016-01-25 10:03 ` Herbert Xu
2016-01-25 10:17 ` Pablo Neira Ayuso
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