netdev - [PATCH net] udp: drop secpath before storing an skb in a receive queue

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Message-ID: <20251014060454.1841122-1-edumazet@google.com>
Date: Tue, 14 Oct 2025 06:04:54 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>
Cc: Simon Horman <horms@...nel.org>, Willem de Bruijn <willemb@...gle.com>, netdev@...r.kernel.org, 
	eric.dumazet@...il.com, Eric Dumazet <edumazet@...gle.com>, 
	Michal Kubecek <mkubecek@...e.cz>, Sabrina Dubroca <sd@...asysnail.net>
Subject: [PATCH net] udp: drop secpath before storing an skb in a receive queue

Michal reported and bisected an issue after recent adoption
of skb_attempt_defer_free() in UDP.

We had the same issue for TCP, that Sabrina fixed in commit 9b6412e6979f
("tcp: drop secpath at the same time as we currently drop dst")

Many thanks to Michal and Sabrina.

Fixes: 6471658dc66c ("udp: use skb_attempt_defer_free()")
Reported-and-bisected-by: Michal Kubecek <mkubecek@...e.cz>
Closes: https://lore.kernel.org/netdev/gpjh4lrotyephiqpuldtxxizrsg6job7cvhiqrw72saz2ubs3h@g6fgbvexgl3r/
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Sabrina Dubroca <sd@...asysnail.net>
---
 net/ipv4/udp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 95241093b7f0..3f05ee70029c 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1709,6 +1709,8 @@ int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
 	int dropcount;
 	int nb = 0;
 
+	secpath_reset(skb);
+
 	rmem = atomic_read(&sk->sk_rmem_alloc);
 	rcvbuf = READ_ONCE(sk->sk_rcvbuf);
 	size = skb->truesize;
-- 
2.51.0.788.g6d19910ace-goog