From: Cong Wang <cong.wang@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Reported-by: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
Cc: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
---
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
