From: Kuniyuki Iwashima <kuniyu@amazon.co.jp> [ Upstream commit f2b2c55e512879a05456eaf5de4d1ed2f7757509 ] If an unconnected socket in a UDP reuseport group connect()s, has_conns is set to 1. Then, when a packet is received, udp[46]_lib_lookup2() scans all sockets in udp_hslot looking for the connected socket with the highest score. However, when the number of sockets bound to the port exceeds max_socks, reuseport_grow() resets has_conns to 0. It can cause udp[46]_lib_lookup2() to return without scanning all sockets, resulting in that packets sent to connected sockets may be distributed to unconnected sockets. Therefore, reuseport_grow() should copy has_conns. Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets") CC: Willem de Bruijn <willemb@google.com> Reviewed-by: Benjamin Herrenschmidt <benh@amazon.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/core/sock_reuseport.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c index fd38cf1d2b02..9c85ef2b7e1d 100644 --- a/net/core/sock_reuseport.c +++ b/net/core/sock_reuseport.c @@ -112,6 +112,7 @@ static struct sock_reuseport *reuseport_grow(struct sock_reuseport *reuse) more_reuse->prog = reuse->prog; more_reuse->reuseport_id = reuse->reuseport_id; more_reuse->bind_inany = reuse->bind_inany; + more_reuse->has_conns = reuse->has_conns; memcpy(more_reuse->socks, reuse->socks, reuse->num_socks * sizeof(struct sock *)); -- 2.25.1