From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Peter Oskolkov <posk@posk.io>
Cc: Jiri Benc <jbenc@redhat.com>, bpf <bpf@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
Peter Oskolkov <posk@google.com>,
Stanislav Fomichev <sdf@google.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH bpf] bpf: lwtunnel: fix reroute supplying invalid dst
Date: Mon, 14 Oct 2019 11:44:52 -0700 [thread overview]
Message-ID: <CAADnVQ+vHYwZGdmeKJRiTXkoOuu+6DNmT1F3RsAOCxhkhsOnSg@mail.gmail.com> (raw)
In-Reply-To: <CAFTs51WM7yC3Z2HDGy9APSgqy1LCczQtFVG_y+X0WdxY9WSd9Q@mail.gmail.com>
On Mon, Oct 14, 2019 at 10:39 AM Peter Oskolkov <posk@posk.io> wrote:
>
> On Sat, Oct 12, 2019 at 9:59 AM Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
> >
> > On Wed, Oct 9, 2019 at 1:31 AM Jiri Benc <jbenc@redhat.com> wrote:
> > >
> > > The dst in bpf_input() has lwtstate field set. As it is of the
> > > LWTUNNEL_ENCAP_BPF type, lwtstate->data is struct bpf_lwt. When the bpf
> > > program returns BPF_LWT_REROUTE, ip_route_input_noref is directly called on
> > > this skb. This causes invalid memory access, as ip_route_input_slow calls
> > > skb_tunnel_info(skb) that expects the dst->lwstate->data to be
> > > struct ip_tunnel_info. This results to struct bpf_lwt being accessed as
> > > struct ip_tunnel_info.
> > >
> > > Drop the dst before calling the IP route input functions (both for IPv4 and
> > > IPv6).
> > >
> > > Reported by KASAN.
> > >
> > > Fixes: 3bd0b15281af ("bpf: add handling of BPF_LWT_REROUTE to lwt_bpf.c")
> > > Cc: Peter Oskolkov <posk@google.com>
> > > Signed-off-by: Jiri Benc <jbenc@redhat.com>
> >
> > Peter and other google folks,
> > please review.
>
> selftests/bpf/test_lwt_ip_encap.sh passes. Seems OK.
>
> Acked-by: Peter Oskolkov <posk@google.com>
Applied to bpf tree. Thanks
prev parent reply other threads:[~2019-10-14 18:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 8:31 [PATCH bpf] bpf: lwtunnel: fix reroute supplying invalid dst Jiri Benc
2019-10-12 16:56 ` Alexei Starovoitov
2019-10-14 17:39 ` Peter Oskolkov
2019-10-14 18:44 ` Alexei Starovoitov [this message]
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