From: David Ahern <dsahern@gmail.com>
To: Peter Oskolkov <posk@google.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
netdev@vger.kernel.org
Cc: Peter Oskolkov <posk@posk.io>, Willem de Bruijn <willemb@google.com>
Subject: Re: [PATCH bpf-next v10 5/7] bpf: add handling of BPF_LWT_REROUTE to lwt_bpf.c
Date: Tue, 12 Feb 2019 19:58:07 -0700 [thread overview]
Message-ID: <681aca28-b4e5-eb0d-46cd-94db7a2c368c@gmail.com> (raw)
In-Reply-To: <20190212173247.121342-6-posk@google.com>
On 2/12/19 10:32 AM, Peter Oskolkov wrote:
> @@ -148,6 +174,87 @@ static int xmit_check_hhlen(struct sk_buff *skb)
> return 0;
> }
>
> +static int bpf_lwt_xmit_reroute(struct sk_buff *skb)
> +{
> + struct net_device *l3mdev = l3mdev_master_dev_rcu(skb_dst(skb)->dev);
> + int oif = l3mdev ? l3mdev->ifindex : 0;
> + struct dst_entry *dst = NULL;
> + struct sock *sk;
> + struct net *net;
> + bool ipv4;
> + int err;
> +
> + if (skb->protocol == htons(ETH_P_IP))
> + ipv4 = true;
> + else if (skb->protocol == htons(ETH_P_IPV6))
> + ipv4 = false;
> + else
> + return -EAFNOSUPPORT;
> +
> + sk = sk_to_full_sk(skb->sk);
> + if (sk) {
> + if (sk->sk_bound_dev_if)
> + oif = sk->sk_bound_dev_if;
> + net = sock_net(sk);
> + } else {
> + net = dev_net(skb_dst(skb)->dev);
> + }
> +
> + if (ipv4) {
> + struct iphdr *iph = ip_hdr(skb);
> + struct flowi4 fl4 = {};
> + struct rtable *rt;
> +
> + fl4.flowi4_oif = oif;
> + fl4.flowi4_mark = skb->mark;
> + fl4.flowi4_uid = sock_net_uid(net, sk);
> + fl4.flowi4_tos = RT_TOS(iph->tos);
> + fl4.flowi4_flags = FLOWI_FLAG_ANYSRC;
> + fl4.flowi4_proto = iph->protocol;
> + fl4.daddr = iph->daddr;
> + fl4.saddr = iph->saddr;
> +
> + rt = ip_route_output_key(net, &fl4);
> + if (IS_ERR(rt) || rt->dst.error)
> + return -EINVAL;
I think you have a dst leak here if rt is valid but the lookup is a
reject (e.g., unreachable or blackhole).
> + dst = &rt->dst;
> + } else {
> + struct ipv6hdr *iph6 = ipv6_hdr(skb);
> + struct flowi6 fl6 = {};
> +
> + fl6.flowi6_oif = oif;
> + fl6.flowi6_mark = skb->mark;
> + fl6.flowi6_uid = sock_net_uid(net, sk);
> + fl6.flowlabel = ip6_flowinfo(iph6);
> + fl6.flowi6_proto = iph6->nexthdr;
> + fl6.daddr = iph6->daddr;
> + fl6.saddr = iph6->saddr;
> +
> + err = ipv6_stub->ipv6_dst_lookup(net, skb->sk, &dst, &fl6);
> + if (err || IS_ERR(dst) || dst->error)
> + return -EINVAL;
same here.
You could check this by adding a route with unreachable as the target in
your tests. Test cleanup and namespace teardown will tell you pretty quick.
next prev parent reply other threads:[~2019-02-13 2:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-12 17:32 [PATCH bpf-next v10 0/7] bpf: add BPF_LWT_ENCAP_IP option to bpf_lwt_push_encap Peter Oskolkov
2019-02-12 17:32 ` [PATCH bpf-next v10 1/7] bpf: add plumbing for BPF_LWT_ENCAP_IP in bpf_lwt_push_encap Peter Oskolkov
2019-02-12 17:32 ` [PATCH bpf-next v10 2/7] bpf: implement BPF_LWT_ENCAP_IP mode " Peter Oskolkov
2019-02-12 17:32 ` [PATCH bpf-next v10 3/7] bpf: handle GSO " Peter Oskolkov
2019-02-12 17:32 ` [PATCH bpf-next v10 4/7] ipv6_stub: add ipv6_route_input stub/proxy Peter Oskolkov
2019-02-12 17:32 ` [PATCH bpf-next v10 5/7] bpf: add handling of BPF_LWT_REROUTE to lwt_bpf.c Peter Oskolkov
2019-02-13 2:58 ` David Ahern [this message]
2019-02-13 19:57 ` Peter Oskolkov
2019-02-13 20:11 ` David Ahern
2019-02-13 20:41 ` Peter Oskolkov
2019-02-12 17:32 ` [PATCH bpf-next v10 6/7] bpf: sync <kdir>/include/.../bpf.h with tools/include/.../bpf.h Peter Oskolkov
2019-02-12 17:32 ` [PATCH bpf-next v10 7/7] selftests: bpf: add test_lwt_ip_encap selftest Peter Oskolkov
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