From: Tycho Andersen <tycho@tycho.ws>
To: Kees Cook <keescook@chromium.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
bpf@vger.kernel.org, coreteam@netfilter.org,
Daniel Borkmann <daniel@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
Florian Westphal <fw@strlen.de>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
Martin KaFai Lau <kafai@fb.com>,
LKML <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Network Development <netdev@vger.kernel.org>,
netfilter-devel@vger.kernel.org,
Pablo Neira Ayuso <pablo@netfilter.org>,
Song Liu <songliubraving@fb.com>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Will Drewry <wad@chromium.org>,
wenxu@ucloud.cn, Yonghong Song <yhs@fb.com>,
syzbot <syzbot+b562969adb2e04af3442@syzkaller.appspotmail.com>
Subject: Re: KASAN: use-after-free Read in seccomp_notify_release (2)
Date: Tue, 23 Apr 2019 15:51:27 -0600 [thread overview]
Message-ID: <20190423215127.GJ3758@cisco> (raw)
In-Reply-To: <CAGXu5jLBd-u=ywxiEjmrLMj9TMRVnLOHHKfWKQ_fEosDFjPoog@mail.gmail.com>
On Tue, Apr 23, 2019 at 02:39:52PM -0700, Kees Cook wrote:
> On Mon, Mar 25, 2019 at 1:02 AM syzbot
> <syzbot+b562969adb2e04af3442@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit: 1bdd3dbf Merge tag 'io_uring-20190323' of git://git.kernel..
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=12ae5b93200000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=9a31fb246de2a622
> > dashboard link: https://syzkaller.appspot.com/bug?extid=b562969adb2e04af3442
> > compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162ca25d200000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1733b53b200000
> >
> > The bug was bisected to:
> >
> > commit a799aea0988ea0d1b1f263e996fdad2f6133c680
> > Author: wenxu <wenxu@ucloud.cn>
> > Date: Wed Jan 9 02:40:11 2019 +0000
> >
> > netfilter: nft_flow_offload: Fix reverse route lookup
>
> This bisection looks bogus?
>
> However, I _can_ trigger the problem on this kernel version with this
> config. (And not with Linus's latest tree.)
>
> The PoC is identical to the prior report[1] that we thought was fixed.
> Perhaps the fix didn't actually fix it? (I mean
> a811dc61559e0c8003f1086c2a4dc8e4d5ae4cb8) But it's been silent for 29
> days now, so I'm not sure what's going on.
>
> Tycho are you able to reproduce this on the older tree?
It looks like this case is using TSYNC and NEW_LISTENER together:
syscall(__NR_seccomp, 1, 0xb, 0x20000140);
and I did fix a uaf with TSYNC and NEW_LISTENER in this series:
https://lore.kernel.org/lkml/20190306201413.14153-2-tycho@tycho.ws/T/#u
which seems like it's probably related. I don't think the above ever
got applied though?
Tycho
next prev parent reply other threads:[~2019-04-23 21:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-25 8:02 KASAN: use-after-free Read in seccomp_notify_release (2) syzbot
2019-04-23 21:39 ` Kees Cook
2019-04-23 21:51 ` Tycho Andersen [this message]
2019-04-23 22:06 ` Kees Cook
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