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xfrm: input: hold netns during deferred transport reinjection

PATCH Applied Ren Wei 2 participants 2 messages May 22 – May 26 1 message not in the archive

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A message that is not in the archive (sent off-list or not yet received): [email protected]

Ren Wei

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#1 lore raw

PATCH 1/1 xfrm: input: hold netns during deferred transport reinjection

From: Zhengchuan Liang <[email protected]>

Transport-mode reinjection stores a struct net pointer in skb->cb and uses it later from xfrm_trans_reinject(). That pointer must stay valid until the deferred callback runs.

Take a netns reference when queueing deferred reinjection work and drop it after the callback completes. Use maybe_get_net() so the queueing path does not revive a namespace that is already being torn down.

This keeps the existing workqueue design and fixes the netns lifetime handling in one place for all users of xfrm_trans_queue_net().

Fixes 7b3801927e52 ("xfrm: introduce xfrm_trans_queue_net")
Cc [email protected]
Reported-by Yuan Tan <[email protected]>
Reported-by Xin Liu <[email protected]>
Co-developed-by Luxing Yin <[email protected]>
Signed-off-by Luxing Yin <[email protected]>
Signed-off-by Zhengchuan Liang <[email protected]>
Signed-off-by Ren Wei <[email protected]>
Assisted-by Codex:gpt-5.4
---
 net/xfrm/xfrm_input.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)
net/xfrm/xfrm_input.c +12 -4
index f65291eba1f6..cd7036a7d5c8 100644
@@ -797,9 +797,12 @@ static void xfrm_trans_reinject(struct work_struct *work)
 	spin_unlock_bh(&trans->queue_lock);
 
 	local_bh_disable();
-	while ((skb = __skb_dequeue(&queue)))
-		XFRM_TRANS_SKB_CB(skb)->finish(XFRM_TRANS_SKB_CB(skb)->net,
-					       NULL, skb);
+	while ((skb = __skb_dequeue(&queue))) {
+		struct net *net = XFRM_TRANS_SKB_CB(skb)->net;
+
+		XFRM_TRANS_SKB_CB(skb)->finish(net, NULL, skb);
+		put_net(net);
+	}
 	local_bh_enable();
 }
 

@@ -807,6 +810,7 @@ int xfrm_trans_queue_net(struct net *net, struct sk_buff *skb,
 			 int (*finish)(struct net *, struct sock *,
 				       struct sk_buff *))
 {
 	struct xfrm_trans_tasklet *trans;
+	struct net *hold_net;
 
 	trans = this_cpu_ptr(&xfrm_trans_tasklet);

@@ -816,8 +820,12 @@ int xfrm_trans_queue_net(struct net *net, struct sk_buff *skb,
 
 	BUILD_BUG_ON(sizeof(struct xfrm_trans_cb) > sizeof(skb->cb));
 
+	hold_net = maybe_get_net(net);
+	if (!hold_net)
+		return -ENODEV;
+
 	XFRM_TRANS_SKB_CB(skb)->finish = finish;
-	XFRM_TRANS_SKB_CB(skb)->net = net;
+	XFRM_TRANS_SKB_CB(skb)->net = hold_net;
 	spin_lock_bh(&trans->queue_lock);
 	__skb_queue_tail(&trans->queue, skb);
 	spin_unlock_bh(&trans->queue_lock);
Signature · 1 line
2.47.3
maintainer Applied
#2 lore raw
Quoted 13 lines · Ren Wei

From: Zhengchuan Liang <[email protected]>

Transport-mode reinjection stores a struct net pointer in skb->cb and uses it later from xfrm_trans_reinject(). That pointer must stay valid until the deferred callback runs.

Take a netns reference when queueing deferred reinjection work and drop it after the callback completes. Use maybe_get_net() so the queueing path does not revive a namespace that is already being torn down.

This keeps the existing workqueue design and fixes the netns lifetime handling in one place for all users of xfrm_trans_queue_net().

Quoted 9 lines
Fixes 7b3801927e52 ("xfrm: introduce xfrm_trans_queue_net")
Cc [email protected]
Reported-by Yuan Tan <[email protected]>
Reported-by Xin Liu <[email protected]>
Co-developed-by Luxing Yin <[email protected]>
Signed-off-by Luxing Yin <[email protected]>
Signed-off-by Zhengchuan Liang <[email protected]>
Signed-off-by Ren Wei <[email protected]>
Assisted-by Codex:gpt-5.4

Applied, thanks a lot!