From: John Fastabend <john.fastabend@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>, netdev@vger.kernel.org
Cc: bpf@vger.kernel.org, Cong Wang <cong.wang@bytedance.com>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Lorenz Bauer <lmb@cloudflare.com>,
Jakub Sitnicki <jakub@cloudflare.com>
Subject: RE: [Patch bpf] udp: validate checksum in udp_read_sock()
Date: Mon, 11 Oct 2021 22:06:01 -0700 [thread overview]
Message-ID: <616517b9b7336_2215c208b2@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20211008204604.38014-1-xiyou.wangcong@gmail.com>
Cong Wang wrote:
> From: Cong Wang <cong.wang@bytedance.com>
>
> It turns out the skb's in sock receive queue could have
> bad checksums, as both ->poll() and ->recvmsg() validate
> checksums. We have to do the same for ->read_sock() path
> too before they are redirected in sockmap.
>
> Fixes: d7f571188ecf ("udp: Implement ->read_sock() for sockmap")
> Reported-by: Daniel Borkmann <daniel@iogearbox.net>
> Reported-by: John Fastabend <john.fastabend@gmail.com>
> Cc: Lorenz Bauer <lmb@cloudflare.com>
> Cc: Jakub Sitnicki <jakub@cloudflare.com>
> Signed-off-by: Cong Wang <cong.wang@bytedance.com>
> ---
> net/ipv4/udp.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> index 8536b2a7210b..0ae8ab5e05b4 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -1808,6 +1808,17 @@ int udp_read_sock(struct sock *sk, read_descriptor_t *desc,
> skb = skb_recv_udp(sk, 0, 1, &err);
> if (!skb)
> return err;
> +
> + if (udp_lib_checksum_complete(skb)) {
> + __UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
> + IS_UDPLITE(sk));
> + __UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
> + IS_UDPLITE(sk));
> + atomic_inc(&sk->sk_drops);
> + kfree_skb(skb);
We could use sock_drop() here? Otherwise looks good thanks.
> + continue;
> + }
> +
> used = recv_actor(desc, skb, 0, skb->len);
> if (used <= 0) {
> if (!copied)
> --
> 2.30.2
>
next prev parent reply other threads:[~2021-10-12 5:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-08 20:46 [Patch bpf] udp: validate checksum in udp_read_sock() Cong Wang
2021-10-12 5:06 ` John Fastabend [this message]
2021-10-13 16:38 ` Cong Wang
2021-10-13 16:51 ` John Fastabend
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