| Message ID | 20200721061531.94236-2-kuniyu@amazon.co.jp |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | udp: Fix reuseport selection with connected sockets. | expand |
On Tue, Jul 21, 2020 at 2:16 AM Kuniyuki Iwashima <kuniyu@amazon.co.jp> wrote: > > 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> Thanks. Yes, I missed this resize operation when adding the field.
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 *));
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> --- net/core/sock_reuseport.c | 1 + 1 file changed, 1 insertion(+)