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 <will...@google.com>
Reviewed-by: Benjamin Herrenschmidt <b...@amazon.com>
Signed-off-by: Kuniyuki Iwashima <kun...@amazon.co.jp>
---
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 adcb3aea576d..bbdd3c7b6cb5 100644
--- a/net/core/sock_reuseport.c
+++ b/net/core/sock_reuseport.c
@@ -101,6 +101,7 @@ 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 *));
--
2.17.2 (Apple Git-113)
