netfilter: ipset: refactor deprecated strncpy

Use `strscpy_pad` instead of `strncpy`.

Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

net/netfilter/ipset/ip_set_core.c

@@ -872,7 +872,7 @@ ip_set_name_byindex(struct net *net, ip_set_id_t index, char *name)
 	BUG_ON(!set);
 
 	read_lock_bh(&ip_set_ref_lock);
-	strncpy(name, set->name, IPSET_MAXNAMELEN);
+	strscpy_pad(name, set->name, IPSET_MAXNAMELEN);
 	read_unlock_bh(&ip_set_ref_lock);
 }
 EXPORT_SYMBOL_GPL(ip_set_name_byindex);
@@ -1326,7 +1326,7 @@ static int ip_set_rename(struct sk_buff *skb, const struct nfnl_info *info,
 			goto out;
 		}
 	}
-	strncpy(set->name, name2, IPSET_MAXNAMELEN);
+	strscpy_pad(set->name, name2, IPSET_MAXNAMELEN);
 
 out:
 	write_unlock_bh(&ip_set_ref_lock);
@@ -1380,9 +1380,9 @@ static int ip_set_swap(struct sk_buff *skb, const struct nfnl_info *info,
 		return -EBUSY;
 	}
 
-	strncpy(from_name, from->name, IPSET_MAXNAMELEN);
-	strncpy(from->name, to->name, IPSET_MAXNAMELEN);
-	strncpy(to->name, from_name, IPSET_MAXNAMELEN);
+	strscpy_pad(from_name, from->name, IPSET_MAXNAMELEN);
+	strscpy_pad(from->name, to->name, IPSET_MAXNAMELEN);
+	strscpy_pad(to->name, from_name, IPSET_MAXNAMELEN);
 
 	swap(from->ref, to->ref);
 	ip_set(inst, from_id) = to;