From: Cong Wang cong.wang@bytedance.com
[ Upstream commit 099f896f498a2b26d84f4ddae039b2c542c18b48 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/udp.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 2fffcf2b54f3f..2ce3fca545d37 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)