Commit c64c9c28 authored Jul 26, 2020 by Jakub Sitnicki Committed by Daniel Borkmann Jul 31, 2020

udp, bpf: Ignore connections in reuseport group after BPF sk lookup

When BPF sk lookup invokes reuseport handling for the selected socket, it
should ignore the fact that reuseport group can contain connected UDP
sockets. With BPF sk lookup this is not relevant as we are not scoring
sockets to find the best match, which might be a connected UDP socket.

Fix it by unconditionally accepting the socket selected by reuseport.

This fixes the following two failures reported by test_progs.

  # ./test_progs -t sk_lookup
  ...
  #73/14 UDP IPv4 redir and reuseport with conns:FAIL
  ...
  #73/20 UDP IPv6 redir and reuseport with conns:FAIL
  ...

Fixes: a57066b1 ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net"

)
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200726120228.1414348-1-jakub@cloudflare.com

parent 50450fc7

net/ipv4/udp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -473,7 +473,7 @@ static struct sock udp4_lookup_run_bpf(struct net net,
		return sk;

		reuse_sk = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
		if (reuse_sk && !reuseport_has_conns(sk, false))
		if (reuse_sk)
		sk = reuse_sk;
		return sk;
		}

net/ipv6/udp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -208,7 +208,7 @@ static inline struct sock udp6_lookup_run_bpf(struct net net,
		return sk;

		reuse_sk = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
		if (reuse_sk && !reuseport_has_conns(sk, false))
		if (reuse_sk)
		sk = reuse_sk;
		return sk;
		}

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