If "udp_cmsg_send()" returned 0 (i.e. only UDP cmsg), "connected" should not be set to 0. Otherwise it stops the connected socket from using the cached route.

Fixes: 2e8de8576343 ("udp: add gso segment cmsg") Signed-off-by: Yick Xie yick.xie@gmail.com Cc: stable@vger.kernel.org --- v3: Fix the IPV6 counterpart and revise the subject v2: Add Fixes tag v1: https://lore.kernel.org/netdev/20240414195213.106209-1-yick.xie@gmail.com/ --- net/ipv4/udp.c | 5 +++-- net/ipv6/udp.c | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index c02bf011d4a6..420905be5f30 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1123,16 +1123,17 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)

if (msg->msg_controllen) { err = udp_cmsg_send(sk, msg, &ipc.gso_size); - if (err > 0) + if (err > 0) { err = ip_cmsg_send(sk, msg, &ipc, sk->sk_family == AF_INET6); + connected = 0; + } if (unlikely(err < 0)) { kfree(ipc.opt); return err; } if (ipc.opt) free = 1; - connected = 0; } if (!ipc.opt) { struct ip_options_rcu *inet_opt; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 8b1dd7f51249..1a4cccdd40c9 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1474,9 +1474,11 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) ipc6.opt = opt;

err = udp_cmsg_send(sk, msg, &ipc6.gso_size); - if (err > 0) + if (err > 0) { err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, fl6, &ipc6); + connected = false; + } if (err < 0) { fl6_sock_release(flowlabel); return err; @@ -1488,7 +1490,6 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) } if (!(opt->opt_nflen|opt->opt_flen)) opt = NULL; - connected = false; } if (!opt) { opt = txopt_get(np);