bond: Check length of IFLA_BOND_ARP_IP_TARGET attributes

Fixes: 7f28fa10 ("bonding: add arp_ip_target netlink support")
Reported-by: NJohn Fastabend <john.fastabend@gmail.com>
Cc: Scott Feldman <sfeldma@cumulusnetworks.com>
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_netlink.c

@@ -225,7 +225,12 @@ static int bond_changelink(struct net_device *bond_dev,
 
 		bond_option_arp_ip_targets_clear(bond);
 		nla_for_each_nested(attr, data[IFLA_BOND_ARP_IP_TARGET], rem) {
-			__be32 target = nla_get_be32(attr);
+			__be32 target;
+
+			if (nla_len(attr) < sizeof(target))
+				return -EINVAL;
+
+			target = nla_get_be32(attr);
 
 			bond_opt_initval(&newval, (__force u64)target);
 			err = __bond_opt_set(bond, BOND_OPT_ARP_TARGETS,