[PATCH net v2 2/3] xfrm: Add an activate() offload dev op

[avivh@mellanox.com]

From: Aviv Heller <avivh@mellanox.com>

Adding the state to the offload device prior to replay init in
xfrm_state_construct() will result in NULL dereference if a matching
ESP packet is received in between.

In order to inhibit driver offload logic from processing the state's
packets prior to the xfrm_state object being completely initialized and
added to the SADBs, a new activate() operation was added to inform the
driver the aforementioned conditions have been met.

Signed-off-by: Aviv Heller <avivh@mellanox.com>
Signed-off-by: Yossi Kuperman <yossiku@mellanox.com>
---
v1 -> v2:
	- Separate to state addition and then activation, instead
	  of relocating dev state addition call.
---
 include/linux/netdevice.h |  1 +
 include/net/xfrm.h        | 12 ++++++++++++
 net/xfrm/xfrm_user.c      |  5 +++++
 3 files changed, 18 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2eaac7d..c6ca356 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -819,6 +819,7 @@ struct netdev_xdp {
 #ifdef CONFIG_XFRM_OFFLOAD
 struct xfrmdev_ops {
 	int	(*xdo_dev_state_add) (struct xfrm_state *x);
+	void	(*xdo_dev_state_activate) (struct xfrm_state *x);
 	void	(*xdo_dev_state_delete) (struct xfrm_state *x);
 	void	(*xdo_dev_state_free) (struct xfrm_state *x);
 	bool	(*xdo_dev_offload_ok) (struct sk_buff *skb,
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index e015e16..324374e 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1877,6 +1877,14 @@ static inline bool xfrm_dst_offload_ok(struct dst_entry *dst)
 	return false;
 }
 
+static inline void xfrm_dev_state_activate(struct xfrm_state *x)
+{
+	struct xfrm_state_offload *xso = &x->xso;
+
+	if (xso->dev && xso->dev->xfrmdev_ops->xdo_dev_state_activate)
+		xso->dev->xfrmdev_ops->xdo_dev_state_activate(x);
+}
+
 static inline void xfrm_dev_state_delete(struct xfrm_state *x)
 {
 	struct xfrm_state_offload *xso = &x->xso;
@@ -1907,6 +1915,10 @@ static inline int xfrm_dev_state_add(struct net *net, struct xfrm_state *x, stru
 	return 0;
 }
 
+static inline void xfrm_dev_state_activate(struct xfrm_state *x)
+{
+}
+
 static inline void xfrm_dev_state_delete(struct xfrm_state *x)
 {
 }
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index e44a0fe..d06f579 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -662,6 +662,11 @@ static int xfrm_add_sa(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto out;
 	}
 
+	spin_lock_bh(&x->lock);
+	if (x->km.state == XFRM_STATE_VALID)
+		xfrm_dev_state_activate(x);
+	spin_unlock_bh(&x->lock);
+
 	c.seq = nlh->nlmsg_seq;
 	c.portid = nlh->nlmsg_pid;
 	c.event = nlh->nlmsg_type;
-- 
1.8.3.1