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udp: Validate checksum in udp_read_sock()

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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>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20211115044006.26068-1-xiyou.wangcong@gmail.com
This commit is contained in:
Cong Wang 2021-11-14 20:40:06 -08:00 committed by Daniel Borkmann
parent 353050be4c
commit 099f896f49
1 changed files with 11 additions and 0 deletions
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11
net/ipv4/udp.c
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@ -1807,6 +1807,17 @@ int udp_read_sock(struct sock *sk, read_descriptor_t *desc,
skb = skb_recv_udp(sk, 0, 1, &err); skb = skb_recv_udp(sk, 0, 1, &err);
if (!skb) if (!skb)
return err; 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); used = recv_actor(desc, skb, 0, skb->len);
if (used <= 0) { if (used <= 0) {
if (!copied) if (!copied)