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, 29 insertions, 35 deletions

diff --git a/kernel/net/netfilter/ipset/ip_set_bitmap_ipmac.c b/kernel/net/netfilter/ipset/ip_set_bitmap_ipmac.c
index 61264da..0f1cf29 100644
--- a/kernel/net/netfilter/ipset/ip_set_bitmap_ipmac.c
+++ b/kernel/net/netfilter/ipset/ip_set_bitmap_ipmac.c
@@ -47,24 +47,26 @@ enum {
 /* Type structure */
 struct bitmap_ipmac {
 	void *members;		/* the set members */
-	void *extensions;	/* MAC + data extensions */
 	u32 first_ip;		/* host byte order, included in range */
 	u32 last_ip;		/* 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 collector */
+	unsigned char extensions[0]	/* MAC + data extensions */
+		__aligned(__alignof__(u64));
 };
 
 /* ADT structure for generic function args */
 struct bitmap_ipmac_adt_elem {
+	unsigned char ether[ETH_ALEN] __aligned(2);
 	u16 id;
-	unsigned char *ether;
+	u16 add_mac;
 };
 
 struct bitmap_ipmac_elem {
 	unsigned char ether[ETH_ALEN];
 	unsigned char filled;
-} __aligned(8);
+} __aligned(__alignof__(u64));
 
 static inline u32
 ip_to_id(const struct bitmap_ipmac *m, u32 ip)
@@ -72,11 +74,11 @@ ip_to_id(const struct bitmap_ipmac *m, u32 ip)
 	return ip - m->first_ip;
 }
 
-static inline struct bitmap_ipmac_elem *
-get_elem(void *extensions, u16 id, size_t dsize)
-{
-	return (struct bitmap_ipmac_elem *)(extensions + id * dsize);
-}
+#define get_elem(extensions, id, dsize)		\
+	(struct bitmap_ipmac_elem *)(extensions + (id) * (dsize))
+
+#define get_const_elem(extensions, id, dsize)	\
+	(const struct bitmap_ipmac_elem *)(extensions + (id) * (dsize))
 
 /* Common functions */
 
@@ -88,10 +90,9 @@ bitmap_ipmac_do_test(const struct bitmap_ipmac_adt_elem *e,
 
 	if (!test_bit(e->id, map->members))
 		return 0;
-	elem = get_elem(map->extensions, e->id, dsize);
-	if (elem->filled == MAC_FILLED)
-		return !e->ether ||
-		       ether_addr_equal(e->ether, elem->ether);
+	elem = get_const_elem(map->extensions, e->id, dsize);
+	if (e->add_mac && elem->filled == MAC_FILLED)
+		return ether_addr_equal(e->ether, elem->ether);
 	/* Trigger kernel to fill out the ethernet address */
 	return -EAGAIN;
 }
@@ -103,7 +104,7 @@ bitmap_ipmac_gc_test(u16 id, const struct bitmap_ipmac *map, size_t dsize)
 
 	if (!test_bit(id, map->members))
 		return 0;
-	elem = get_elem(map->extensions, id, dsize);
+	elem = get_const_elem(map->extensions, id, dsize);
 	/* Timer not started for the incomplete elements */
 	return elem->filled == MAC_FILLED;
 }
@@ -133,7 +134,7 @@ bitmap_ipmac_add_timeout(unsigned long *timeout,
 		 * and we can reuse it later when MAC is filled out,
 		 * possibly by the kernel
 		 */
-		if (e->ether)
+		if (e->add_mac)
 			ip_set_timeout_set(timeout, t);
 		else
 			*timeout = t;
@@ -150,7 +151,7 @@ bitmap_ipmac_do_add(const struct bitmap_ipmac_adt_elem *e,
 	elem = get_elem(map->extensions, e->id, dsize);
 	if (test_bit(e->id, map->members)) {
 		if (elem->filled == MAC_FILLED) {
-			if (e->ether &&
+			if (e->add_mac &&
 			    (flags & IPSET_FLAG_EXIST) &&
 			    !ether_addr_equal(e->ether, elem->ether)) {
 				/* memcpy isn't atomic */
@@ -159,7 +160,7 @@ bitmap_ipmac_do_add(const struct bitmap_ipmac_adt_elem *e,
 				ether_addr_copy(elem->ether, e->ether);
 			}
 			return IPSET_ADD_FAILED;
-		} else if (!e->ether)
+		} else if (!e->add_mac)
 			/* Already added without ethernet address */
 			return IPSET_ADD_FAILED;
 		/* Fill the MAC address and trigger the timer activation */
@@ -168,7 +169,7 @@ bitmap_ipmac_do_add(const struct bitmap_ipmac_adt_elem *e,
 		ether_addr_copy(elem->ether, e->ether);
 		elem->filled = MAC_FILLED;
 		return IPSET_ADD_START_STORED_TIMEOUT;
-	} else if (e->ether) {
+	} else if (e->add_mac) {
 		/* We can store MAC too */
 		ether_addr_copy(elem->ether, e->ether);
 		elem->filled = MAC_FILLED;
@@ -191,7 +192,7 @@ bitmap_ipmac_do_list(struct sk_buff *skb, const struct bitmap_ipmac *map,
 		     u32 id, size_t dsize)
 {
 	const struct bitmap_ipmac_elem *elem =
-		get_elem(map->extensions, id, dsize);
+		get_const_elem(map->extensions, id, dsize);
 
 	return nla_put_ipaddr4(skb, IPSET_ATTR_IP,
 			       htonl(map->first_ip + id)) ||
@@ -213,7 +214,7 @@ bitmap_ipmac_kadt(struct ip_set *set, const struct sk_buff *skb,
 {
 	struct bitmap_ipmac *map = set->data;
 	ipset_adtfn adtfn = set->variant->adt[adt];
-	struct bitmap_ipmac_adt_elem e = { .id = 0 };
+	struct bitmap_ipmac_adt_elem e = { .id = 0, .add_mac = 1  };
 	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
 	u32 ip;
 
@@ -231,7 +232,7 @@ bitmap_ipmac_kadt(struct ip_set *set, const struct sk_buff *skb,
 		return -EINVAL;
 
 	e.id = ip_to_id(map, ip);
-	e.ether = eth_hdr(skb)->h_source;
+	memcpy(e.ether, eth_hdr(skb)->h_source, ETH_ALEN);
 
 	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
 }
@@ -265,11 +266,10 @@ bitmap_ipmac_uadt(struct ip_set *set, struct nlattr *tb[],
 		return -IPSET_ERR_BITMAP_RANGE;
 
 	e.id = ip_to_id(map, ip);
-	if (tb[IPSET_ATTR_ETHER])
-		e.ether = nla_data(tb[IPSET_ATTR_ETHER]);
-	else
-		e.ether = NULL;
-
+	if (tb[IPSET_ATTR_ETHER]) {
+		memcpy(e.ether, nla_data(tb[IPSET_ATTR_ETHER]), ETH_ALEN);
+		e.add_mac = 1;
+	}
 	ret = adtfn(set, &e, &ext, &ext, flags);
 
 	return ip_set_eexist(ret, flags) ? 0 : ret;
@@ -300,13 +300,6 @@ init_map_ipmac(struct ip_set *set, struct bitmap_ipmac *map,
 	map->members = ip_set_alloc(map->memsize);
 	if (!map->members)
 		return false;
-	if (set->dsize) {
-		map->extensions = ip_set_alloc(set->dsize * elements);
-		if (!map->extensions) {
-			kfree(map->members);
-			return false;
-		}
-	}
 	map->first_ip = first_ip;
 	map->last_ip = last_ip;
 	map->elements = elements;
@@ -361,14 +354,15 @@ bitmap_ipmac_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
 	if (elements > IPSET_BITMAP_MAX_RANGE + 1)
 		return -IPSET_ERR_BITMAP_RANGE_SIZE;
 
-	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	set->dsize = ip_set_elem_len(set, tb,
+				     sizeof(struct bitmap_ipmac_elem),
+				     __alignof__(struct bitmap_ipmac_elem));
+	map = ip_set_alloc(sizeof(*map) + elements * set->dsize);
 	if (!map)
 		return -ENOMEM;
 
 	map->memsize = bitmap_bytes(0, elements - 1);
 	set->variant = &bitmap_ipmac;
-	set->dsize = ip_set_elem_len(set, tb,
-				     sizeof(struct bitmap_ipmac_elem));
 	if (!init_map_ipmac(set, map, first_ip, last_ip, elements)) {
 		kfree(map);
 		return -ENOMEM;