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>

1 files changed, 7 insertions, 11 deletions

diff --git a/net/netfilter/ipset/ip_set_bitmap_port.c b/net/netfilter/ipset/ip_set_bitmap_port.c
index 5338ccd5da46..7f0c733358a4 100644
--- a/net/netfilter/ipset/ip_set_bitmap_port.c
+++ b/net/netfilter/ipset/ip_set_bitmap_port.c
@@ -35,12 +35,13 @@ MODULE_ALIAS("ip_set_bitmap:port");
 /* Type structure */
 struct bitmap_port {
 	void *members;		/* the set members */
-	void *extensions;	/* data extensions */
 	u16 first_port;		/* host byte order, included in range */
 	u16 last_port;		/* host byte order, included in range */
 	u32 elements;		/* number of max elements in the set */
 	size_t memsize;		/* members size */
 	struct timer_list gc;	/* garbage collection */
+	unsigned char extensions[0]	/* data extensions */
+		__aligned(__alignof__(u64));
 };
 
 /* ADT structure for generic function args */
@@ -209,13 +210,6 @@ init_map_port(struct ip_set *set, struct bitmap_port *map,
 	map->members = ip_set_alloc(map->memsize);
 	if (!map->members)
 		return false;
-	if (set->dsize) {
-		map->extensions = ip_set_alloc(set->dsize * map->elements);
-		if (!map->extensions) {
-			kfree(map->members);
-			return false;
-		}
-	}
 	map->first_port = first_port;
 	map->last_port = last_port;
 	set->timeout = IPSET_NO_TIMEOUT;
@@ -232,6 +226,7 @@ bitmap_port_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
 {
 	struct bitmap_port *map;
 	u16 first_port, last_port;
+	u32 elements;
 
 	if (unlikely(!ip_set_attr_netorder(tb, IPSET_ATTR_PORT) ||
 		     !ip_set_attr_netorder(tb, IPSET_ATTR_PORT_TO) ||
@@ -248,14 +243,15 @@ bitmap_port_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
 		last_port = tmp;
 	}
 
-	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	elements = last_port - first_port + 1;
+	set->dsize = ip_set_elem_len(set, tb, 0, 0);
+	map = ip_set_alloc(sizeof(*map) + elements * set->dsize);
 	if (!map)
 		return -ENOMEM;
 
-	map->elements = last_port - first_port + 1;
+	map->elements = elements;
 	map->memsize = bitmap_bytes(0, map->elements);
 	set->variant = &bitmap_port;
-	set->dsize = ip_set_elem_len(set, tb, 0);
 	if (!init_map_port(set, map, first_port, last_port)) {
 		kfree(map);
 		return -ENOMEM;