bonding: fix null pointer deref in bond_ipsec_offload_ok

jira LE-3201
cve CVE-2024-44990
Rebuild_History Non-Buildable kernel-rt-4.18.0-553.27.1.rt7.368.el8_10
commit-author Nikolay Aleksandrov <[email protected]>
commit 95c90e4

We must check if there is an active slave before dereferencing the pointer.

Fixes: 18cb261 ("bonding: support hardware encryption offload to slaves")
	Signed-off-by: Nikolay Aleksandrov <[email protected]>
	Reviewed-by: Hangbin Liu <[email protected]>
	Reviewed-by: Eric Dumazet <[email protected]>
	Signed-off-by: Paolo Abeni <[email protected]>

(cherry picked from commit 95c90e4)
	Signed-off-by: Jonathan Maple <[email protected]>

Author: PlaidCat

drivers/net/bonding/bond_main.c

@@ -579,6 +579,8 @@ static bool bond_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
 	bond = netdev_priv(bond_dev);
 	rcu_read_lock();
 	curr_active = rcu_dereference(bond->curr_active_slave);
+	if (!curr_active)
+		goto out;
 	real_dev = curr_active->dev;
 
 	if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {