From: Sabrina Dubroca <sd@queasysnail.net>
Date: Mon, 25 Nov 2019 14:48:58 +0100
Subject: xfrm: introduce xfrm_trans_queue_net
Patch-mainline: v5.6-rc1
Git-commit: 7b3801927e52f8621de311277f7fc727635019e7
References: bsc#1176447

This will be used by TCP encapsulation to write packets to the encap
socket without holding the user socket's lock. Without this reinjection,
we're already holding the lock of the user socket, and then try to lock
the encap socket as well when we enqueue the encrypted packet.

While at it, add a BUILD_BUG_ON like we usually do for skb->cb, since
it's missing for struct xfrm_trans_cb.

Co-developed-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/net/xfrm.h    |    3 +++
 net/xfrm/xfrm_input.c |   21 +++++++++++++++++----
 2 files changed, 20 insertions(+), 4 deletions(-)

--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1547,6 +1547,9 @@ int __xfrm_init_state(struct xfrm_state
 int xfrm_init_state(struct xfrm_state *x);
 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type);
 int xfrm_input_resume(struct sk_buff *skb, int nexthdr);
+int xfrm_trans_queue_net(struct net *net, struct sk_buff *skb,
+			 int (*finish)(struct net *, struct sock *,
+				       struct sk_buff *));
 int xfrm_trans_queue(struct sk_buff *skb,
 		     int (*finish)(struct net *, struct sock *,
 				   struct sk_buff *));
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -36,6 +36,7 @@ struct xfrm_trans_cb {
 #endif
 	} header;
 	int (*finish)(struct net *net, struct sock *sk, struct sk_buff *skb);
+	struct net *net;
 };
 
 #define XFRM_TRANS_SKB_CB(__skb) ((struct xfrm_trans_cb *)&((__skb)->cb[0]))
@@ -766,12 +767,13 @@ static void xfrm_trans_reinject(unsigned
 	skb_queue_splice_init(&trans->queue, &queue);
 
 	while ((skb = __skb_dequeue(&queue)))
-		XFRM_TRANS_SKB_CB(skb)->finish(dev_net(skb->dev), NULL, skb);
+		XFRM_TRANS_SKB_CB(skb)->finish(XFRM_TRANS_SKB_CB(skb)->net,
+					       NULL, skb);
 }
 
-int xfrm_trans_queue(struct sk_buff *skb,
-		     int (*finish)(struct net *, struct sock *,
-				   struct sk_buff *))
+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;
 
@@ -780,11 +782,22 @@ int xfrm_trans_queue(struct sk_buff *skb
 	if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
 		return -ENOBUFS;
 
+	BUILD_BUG_ON(sizeof(struct xfrm_trans_cb) > sizeof(skb->cb));
+
 	XFRM_TRANS_SKB_CB(skb)->finish = finish;
+	XFRM_TRANS_SKB_CB(skb)->net = net;
 	__skb_queue_tail(&trans->queue, skb);
 	tasklet_schedule(&trans->tasklet);
 	return 0;
 }
+EXPORT_SYMBOL(xfrm_trans_queue_net);
+
+int xfrm_trans_queue(struct sk_buff *skb,
+		     int (*finish)(struct net *, struct sock *,
+				   struct sk_buff *))
+{
+	return xfrm_trans_queue_net(dev_net(skb->dev), skb, finish);
+}
 EXPORT_SYMBOL(xfrm_trans_queue);
 
 void __init xfrm_input_init(void)