From: Cong Wang <xiyou.wangcong@gmail.com>
To: 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: [Patch bpf] udp: validate checksum in udp_read_sock()
Date: Fri, 8 Oct 2021 13:46:04 -0700 [thread overview]
Message-ID: <20211008204604.38014-1-xiyou.wangcong@gmail.com> (raw)
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);
+ continue;
+ }
+
used = recv_actor(desc, skb, 0, skb->len);
if (used <= 0) {
if (!copied)
--
2.30.2
next reply other threads:[~2021-10-08 20:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-08 20:46 Cong Wang [this message]
2021-10-12 5:06 ` [Patch bpf] udp: validate checksum in udp_read_sock() John Fastabend
2021-10-13 16:38 ` Cong Wang
2021-10-13 16:51 ` John Fastabend
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