[PATCH net-next v3 2/4] udp: Remove disconnected sockets from the 4-tuple hash
From: Jordan Rife <hidden>
Date: 2026-03-30 21:57:13
Also in:
bpf
Subsystem:
networking [general], the rest, user datagram protocol (udp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Willem de Bruijn
Currently, previously connected sockets stay in the 4-tuple hash after __udp_disconnect if the socket was bound to a specific port or port:addr pair. This is benign if inet_daddr/inet_dport are cleared as well, since lookups matching the old 4-tuple will not find this socket in the hash. To maintain the same behavior as before if inet_daddr/inet_dport are not cleared in __udp_disconnect, always remove a socket from the hash on disconnect or abort to prevent a lookup for the original 4-tuple from finding the socket. Signed-off-by: Jordan Rife <redacted> --- net/ipv4/udp.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d91c587c3657..6e5ba2ce9314 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c@@ -2235,10 +2235,20 @@ int __udp_disconnect(struct sock *sk, int flags) } EXPORT_SYMBOL(__udp_disconnect); +static int udp_disconnect_unhash4(struct sock *sk, int flags) +{ + struct udp_table *udptable = udp_get_table_prot(sk); + + udp_unhash4(udptable, sk); + __udp_disconnect(sk, flags); + + return 0; +} + int udp_disconnect(struct sock *sk, int flags) { lock_sock(sk); - __udp_disconnect(sk, flags); + udp_disconnect_unhash4(sk, flags); release_sock(sk); return 0; }
@@ -3254,7 +3264,7 @@ int udp_abort(struct sock *sk, int err) sk->sk_err = err; sk_error_report(sk); - __udp_disconnect(sk, 0); + udp_disconnect_unhash4(sk, 0); out: if (!has_current_bpf_ctx())
--
2.53.0.1118.gaef5881109-goog