netfilter: ipset: Fix extension alignment

The data extensions in ipset lacked the proper memory alignment and
thus could lead to kernel crash on several architectures. Therefore
the structures have been reorganized and alignment attributes added
where needed. The patch was tested on armv7h by Gerhard Wiesinger and
on x86_64, sparc64 by Jozsef Kadlecsik.

Reported-by: Gerhard Wiesinger <lists@wiesinger.com>
Tested-by: Gerhard Wiesinger <lists@wiesinger.com>
Tested-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
diff --git a/net/netfilter/ipset/ip_set_bitmap_gen.h b/net/netfilter/ipset/ip_set_bitmap_gen.h
index d05e759..b0bc475 100644
--- a/net/netfilter/ipset/ip_set_bitmap_gen.h
+++ b/net/netfilter/ipset/ip_set_bitmap_gen.h
@@ -33,7 +33,7 @@
 #define mtype_gc		IPSET_TOKEN(MTYPE, _gc)
 #define mtype			MTYPE
 
-#define get_ext(set, map, id)	((map)->extensions + (set)->dsize * (id))
+#define get_ext(set, map, id)	((map)->extensions + ((set)->dsize * (id)))
 
 static void
 mtype_gc_init(struct ip_set *set, void (*gc)(unsigned long ul_set))
@@ -67,12 +67,9 @@
 		del_timer_sync(&map->gc);
 
 	ip_set_free(map->members);
-	if (set->dsize) {
-		if (set->extensions & IPSET_EXT_DESTROY)
-			mtype_ext_cleanup(set);
-		ip_set_free(map->extensions);
-	}
-	kfree(map);
+	if (set->dsize && set->extensions & IPSET_EXT_DESTROY)
+		mtype_ext_cleanup(set);
+	ip_set_free(map);
 
 	set->data = NULL;
 }
@@ -92,16 +89,14 @@
 {
 	const struct mtype *map = set->data;
 	struct nlattr *nested;
+	size_t memsize = sizeof(*map) + map->memsize;
 
 	nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
 	if (!nested)
 		goto nla_put_failure;
 	if (mtype_do_head(skb, map) ||
 	    nla_put_net32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1)) ||
-	    nla_put_net32(skb, IPSET_ATTR_MEMSIZE,
-			  htonl(sizeof(*map) +
-				map->memsize +
-				set->dsize * map->elements)))
+	    nla_put_net32(skb, IPSET_ATTR_MEMSIZE, htonl(memsize)))
 		goto nla_put_failure;
 	if (unlikely(ip_set_put_flags(skb, set)))
 		goto nla_put_failure;