bonding: Add struct bond_ipesc to manage SA

bonding has been supporting ipsec offload.
When SA is added, bonding just passes SA to its own active real interface.
But it doesn't manage SA.
So, when events(add/del real interface, active real interface change, etc)
occur, bonding can't handle that well because It doesn't manage SA.
So some problems(panic, UAF, refcnt leak)occur.

In order to make it stable, it should manage SA.
That's the reason why struct bond_ipsec is added.
When a new SA is added to bonding interface, it is stored in the
bond_ipsec list. And the SA is passed to a current active real interface.
If events occur, it uses bond_ipsec data to handle these events.
bond->ipsec_list is protected by bond->ipsec_lock.

If a current active real interface is changed, the following logic works.
1. delete all SAs from old active real interface
2. Add all SAs to the new active real interface.
3. If a new active real interface doesn't support ipsec offload or SA's
option, it sets real_dev to NULL.

Fixes: 18cb261a ("bonding: support hardware encryption offload to slaves")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -401,6 +401,7 @@ static int bond_vlan_rx_kill_vid(struct net_device *bond_dev,
 static int bond_ipsec_add_sa(struct xfrm_state *xs)
 {
 	struct net_device *bond_dev = xs->xso.dev;
+	struct bond_ipsec *ipsec;
 	struct bonding *bond;
 	struct slave *slave;
 	int err;
@@ -416,9 +417,6 @@ static int bond_ipsec_add_sa(struct xfrm_state *xs)
 		return -ENODEV;
 	}
 
-	xs->xso.real_dev = slave->dev;
-	bond->xs = xs;
-
 	if (!slave->dev->xfrmdev_ops ||
 	    !slave->dev->xfrmdev_ops->xdo_dev_state_add ||
 	    netif_is_bond_master(slave->dev)) {
@@ -427,11 +425,63 @@ static int bond_ipsec_add_sa(struct xfrm_state *xs)
 		return -EINVAL;
 	}
 
+	ipsec = kmalloc(sizeof(*ipsec), GFP_ATOMIC);
+	if (!ipsec) {
+		rcu_read_unlock();
+		return -ENOMEM;
+	}
+	xs->xso.real_dev = slave->dev;
+
 	err = slave->dev->xfrmdev_ops->xdo_dev_state_add(xs);
+	if (!err) {
+		ipsec->xs = xs;
+		INIT_LIST_HEAD(&ipsec->list);
+		spin_lock_bh(&bond->ipsec_lock);
+		list_add(&ipsec->list, &bond->ipsec_list);
+		spin_unlock_bh(&bond->ipsec_lock);
+	} else {
+		kfree(ipsec);
+	}
 	rcu_read_unlock();
 	return err;
 }
 
+static void bond_ipsec_add_sa_all(struct bonding *bond)
+{
+	struct net_device *bond_dev = bond->dev;
+	struct bond_ipsec *ipsec;
+	struct slave *slave;
+
+	rcu_read_lock();
+	slave = rcu_dereference(bond->curr_active_slave);
+	if (!slave)
+		goto out;
+
+	if (!slave->dev->xfrmdev_ops ||
+	    !slave->dev->xfrmdev_ops->xdo_dev_state_add ||
+	    netif_is_bond_master(slave->dev)) {
+		spin_lock_bh(&bond->ipsec_lock);
+		if (!list_empty(&bond->ipsec_list))
+			slave_warn(bond_dev, slave->dev,
+				   "%s: no slave xdo_dev_state_add\n",
+				   __func__);
+		spin_unlock_bh(&bond->ipsec_lock);
+		goto out;
+	}
+
+	spin_lock_bh(&bond->ipsec_lock);
+	list_for_each_entry(ipsec, &bond->ipsec_list, list) {
+		ipsec->xs->xso.real_dev = slave->dev;
+		if (slave->dev->xfrmdev_ops->xdo_dev_state_add(ipsec->xs)) {
+			slave_warn(bond_dev, slave->dev, "%s: failed to add SA\n", __func__);
+			ipsec->xs->xso.real_dev = NULL;
+		}
+	}
+	spin_unlock_bh(&bond->ipsec_lock);
+out:
+	rcu_read_unlock();
+}
+
 /**
  * bond_ipsec_del_sa - clear out this specific SA
  * @xs: pointer to transformer state struct
@@ -439,6 +489,7 @@ static int bond_ipsec_add_sa(struct xfrm_state *xs)
 static void bond_ipsec_del_sa(struct xfrm_state *xs)
 {
 	struct net_device *bond_dev = xs->xso.dev;
+	struct bond_ipsec *ipsec;
 	struct bonding *bond;
 	struct slave *slave;
 
@@ -452,7 +503,10 @@ static void bond_ipsec_del_sa(struct xfrm_state *xs)
 	if (!slave)
 		goto out;
 
-	xs->xso.real_dev = slave->dev;
+	if (!xs->xso.real_dev)
+		goto out;
+
+	WARN_ON(xs->xso.real_dev != slave->dev);
 
 	if (!slave->dev->xfrmdev_ops ||
 	    !slave->dev->xfrmdev_ops->xdo_dev_state_delete ||
@@ -463,6 +517,48 @@ static void bond_ipsec_del_sa(struct xfrm_state *xs)
 
 	slave->dev->xfrmdev_ops->xdo_dev_state_delete(xs);
 out:
+	spin_lock_bh(&bond->ipsec_lock);
+	list_for_each_entry(ipsec, &bond->ipsec_list, list) {
+		if (ipsec->xs == xs) {
+			list_del(&ipsec->list);
+			kfree(ipsec);
+			break;
+		}
+	}
+	spin_unlock_bh(&bond->ipsec_lock);
+	rcu_read_unlock();
+}
+
+static void bond_ipsec_del_sa_all(struct bonding *bond)
+{
+	struct net_device *bond_dev = bond->dev;
+	struct bond_ipsec *ipsec;
+	struct slave *slave;
+
+	rcu_read_lock();
+	slave = rcu_dereference(bond->curr_active_slave);
+	if (!slave) {
+		rcu_read_unlock();
+		return;
+	}
+
+	spin_lock_bh(&bond->ipsec_lock);
+	list_for_each_entry(ipsec, &bond->ipsec_list, list) {
+		if (!ipsec->xs->xso.real_dev)
+			continue;
+
+		if (!slave->dev->xfrmdev_ops ||
+		    !slave->dev->xfrmdev_ops->xdo_dev_state_delete ||
+		    netif_is_bond_master(slave->dev)) {
+			slave_warn(bond_dev, slave->dev,
+				   "%s: no slave xdo_dev_state_delete\n",
+				   __func__);
+		} else {
+			slave->dev->xfrmdev_ops->xdo_dev_state_delete(ipsec->xs);
+		}
+		ipsec->xs->xso.real_dev = NULL;
+	}
+	spin_unlock_bh(&bond->ipsec_lock);
 	rcu_read_unlock();
 }
 
@@ -474,22 +570,27 @@ static void bond_ipsec_del_sa(struct xfrm_state *xs)
 static bool bond_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
 {
 	struct net_device *bond_dev = xs->xso.dev;
-	struct bonding *bond = netdev_priv(bond_dev);
-	struct slave *curr_active = rcu_dereference(bond->curr_active_slave);
-	struct net_device *slave_dev = curr_active->dev;
+	struct net_device *real_dev;
+	struct slave *curr_active;
+	struct bonding *bond;
+
+	bond = netdev_priv(bond_dev);
+	curr_active = rcu_dereference(bond->curr_active_slave);
+	real_dev = curr_active->dev;
 
 	if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP)
 		return true;
 
-	if (!slave_dev->xfrmdev_ops ||
-	    !slave_dev->xfrmdev_ops->xdo_dev_offload_ok ||
-	    netif_is_bond_master(slave_dev)) {
-		slave_warn(bond_dev, slave_dev, "%s: no slave xdo_dev_offload_ok\n", __func__);
+	if (!xs->xso.real_dev)
+		return false;
+
+	if (!real_dev->xfrmdev_ops ||
+	    !real_dev->xfrmdev_ops->xdo_dev_offload_ok ||
+	    netif_is_bond_master(real_dev)) {
 		return false;
 	}
 
-	xs->xso.real_dev = slave_dev;
-	return slave_dev->xfrmdev_ops->xdo_dev_offload_ok(skb, xs);
+	return real_dev->xfrmdev_ops->xdo_dev_offload_ok(skb, xs);
 }
 
 static const struct xfrmdev_ops bond_xfrmdev_ops = {
@@ -1006,8 +1107,7 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
 		return;
 
 #ifdef CONFIG_XFRM_OFFLOAD
-	if (old_active && bond->xs)
-		bond_ipsec_del_sa(bond->xs);
+	bond_ipsec_del_sa_all(bond);
 #endif /* CONFIG_XFRM_OFFLOAD */
 
 	if (new_active) {
@@ -1082,10 +1182,7 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
 	}
 
 #ifdef CONFIG_XFRM_OFFLOAD
-	if (new_active && bond->xs) {
-		xfrm_dev_state_flush(dev_net(bond->dev), bond->dev, true);
-		bond_ipsec_add_sa(bond->xs);
-	}
+	bond_ipsec_add_sa_all(bond);
 #endif /* CONFIG_XFRM_OFFLOAD */
 
 	/* resend IGMP joins since active slave has changed or
@@ -3343,6 +3440,7 @@ static int bond_master_netdev_event(unsigned long event,
 		return bond_event_changename(event_bond);
 	case NETDEV_UNREGISTER:
 		bond_remove_proc_entry(event_bond);
+		xfrm_dev_state_flush(dev_net(bond_dev), bond_dev, true);
 		break;
 	case NETDEV_REGISTER:
 		bond_create_proc_entry(event_bond);
@@ -4910,7 +5008,8 @@ void bond_setup(struct net_device *bond_dev)
 #ifdef CONFIG_XFRM_OFFLOAD
 	/* set up xfrm device ops (only supported in active-backup right now) */
 	bond_dev->xfrmdev_ops = &bond_xfrmdev_ops;
-	bond->xs = NULL;
+	INIT_LIST_HEAD(&bond->ipsec_list);
+	spin_lock_init(&bond->ipsec_lock);
 #endif /* CONFIG_XFRM_OFFLOAD */
 
 	/* don't acquire bond device's netif_tx_lock when transmitting */

include/net/bonding.h

@@ -201,6 +201,11 @@ struct bond_up_slave {
  */
 #define BOND_LINK_NOCHANGE -1
 
+struct bond_ipsec {
+	struct list_head list;
+	struct xfrm_state *xs;
+};
+
 /*
  * Here are the locking policies for the two bonding locks:
  * Get rcu_read_lock when reading or RTNL when writing slave list.
@@ -249,7 +254,9 @@ struct bonding {
 #endif /* CONFIG_DEBUG_FS */
 	struct rtnl_link_stats64 bond_stats;
 #ifdef CONFIG_XFRM_OFFLOAD
-	struct xfrm_state *xs;
+	struct list_head ipsec_list;
+	/* protecting ipsec_list */
+	spinlock_t ipsec_lock;
 #endif /* CONFIG_XFRM_OFFLOAD */
 };