[PATCH 1/1] netfilter: ipset: use bitmap infrastructure completely

[PATCH 1/1] netfilter: ipset: use bitmap infrastructure completely

[Kadlecsik József]

The bitmap allocation did not use full unsigned long sizes
when calculating the required size and that was triggered by KASAN
as slab-out-of-bounds read in several places. The patch fixes all
of them.

Reported-by: syzbot+fabca5cbf5e54f3fe2de@syzkaller.appspotmail.com
Reported-by: syzbot+827ced406c9a1d9570ed@syzkaller.appspotmail.com
Reported-by: syzbot+190d63957b22ef673ea5@syzkaller.appspotmail.com
Reported-by: syzbot+dfccdb2bdb4a12ad425e@syzkaller.appspotmail.com
Reported-by: syzbot+df0d0f5895ef1f41a65b@syzkaller.appspotmail.com
Reported-by: syzbot+b08bd19bb37513357fd4@syzkaller.appspotmail.com
Reported-by: syzbot+53cdd0ec0bbabd53370a@syzkaller.appspotmail.com
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
---
 include/linux/netfilter/ipset/ip_set.h    | 7 -------
 net/netfilter/ipset/ip_set_bitmap_gen.h   | 2 +-
 net/netfilter/ipset/ip_set_bitmap_ip.c    | 6 +++---
 net/netfilter/ipset/ip_set_bitmap_ipmac.c | 6 +++---
 net/netfilter/ipset/ip_set_bitmap_port.c  | 6 +++---
 5 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/include/linux/netfilter/ipset/ip_set.h b/include/linux/netfilter/ipset/ip_set.h
index 4d8b1eaf7708..908d38dbcb91 100644
--- a/include/linux/netfilter/ipset/ip_set.h
+++ b/include/linux/netfilter/ipset/ip_set.h
@@ -426,13 +426,6 @@ ip6addrptr(const struct sk_buff *skb, bool src, struct in6_addr *addr)
 	       sizeof(*addr));
 }
 
-/* Calculate the bytes required to store the inclusive range of a-b */
-static inline int
-bitmap_bytes(u32 a, u32 b)
-{
-	return 4 * ((((b - a + 8) / 8) + 3) / 4);
-}
-
 /* How often should the gc be run by default */
 #define IPSET_GC_TIME			(3 * 60)
 
diff --git a/net/netfilter/ipset/ip_set_bitmap_gen.h b/net/netfilter/ipset/ip_set_bitmap_gen.h
index 077a2cb65fcb..26ab0e9612d8 100644
--- a/net/netfilter/ipset/ip_set_bitmap_gen.h
+++ b/net/netfilter/ipset/ip_set_bitmap_gen.h
@@ -75,7 +75,7 @@ mtype_flush(struct ip_set *set)
 
 	if (set->extensions & IPSET_EXT_DESTROY)
 		mtype_ext_cleanup(set);
-	memset(map->members, 0, map->memsize);
+	bitmap_zero(map->members, map->elements);
 	set->elements = 0;
 	set->ext_size = 0;
 }
diff --git a/net/netfilter/ipset/ip_set_bitmap_ip.c b/net/netfilter/ipset/ip_set_bitmap_ip.c
index abe8f77d7d23..0a2196f59106 100644
--- a/net/netfilter/ipset/ip_set_bitmap_ip.c
+++ b/net/netfilter/ipset/ip_set_bitmap_ip.c
@@ -37,7 +37,7 @@ MODULE_ALIAS("ip_set_bitmap:ip");
 
 /* Type structure */
 struct bitmap_ip {
-	void *members;		/* the set members */
+	unsigned long *members;	/* the set members */
 	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 */
@@ -220,7 +220,7 @@ init_map_ip(struct ip_set *set, struct bitmap_ip *map,
 	    u32 first_ip, u32 last_ip,
 	    u32 elements, u32 hosts, u8 netmask)
 {
-	map->members = ip_set_alloc(map->memsize);
+	map->members = bitmap_zalloc(elements, GFP_KERNEL | __GFP_NOWARN);
 	if (!map->members)
 		return false;
 	map->first_ip = first_ip;
@@ -322,7 +322,7 @@ bitmap_ip_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
 	if (!map)
 		return -ENOMEM;
 
-	map->memsize = bitmap_bytes(0, elements - 1);
+	map->memsize = BITS_TO_LONGS(elements) * sizeof(unsigned long);
 	set->variant = &bitmap_ip;
 	if (!init_map_ip(set, map, first_ip, last_ip,
 			 elements, hosts, netmask)) {
diff --git a/net/netfilter/ipset/ip_set_bitmap_ipmac.c b/net/netfilter/ipset/ip_set_bitmap_ipmac.c
index b618713297da..739e343efaf6 100644
--- a/net/netfilter/ipset/ip_set_bitmap_ipmac.c
+++ b/net/netfilter/ipset/ip_set_bitmap_ipmac.c
@@ -42,7 +42,7 @@ enum {
 
 /* Type structure */
 struct bitmap_ipmac {
-	void *members;		/* the set members */
+	unsigned long *members;	/* the set members */
 	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 */
@@ -299,7 +299,7 @@ static bool
 init_map_ipmac(struct ip_set *set, struct bitmap_ipmac *map,
 	       u32 first_ip, u32 last_ip, u32 elements)
 {
-	map->members = ip_set_alloc(map->memsize);
+	map->members = bitmap_zalloc(elements, GFP_KERNEL | __GFP_NOWARN);
 	if (!map->members)
 		return false;
 	map->first_ip = first_ip;
@@ -360,7 +360,7 @@ bitmap_ipmac_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
 	if (!map)
 		return -ENOMEM;
 
-	map->memsize = bitmap_bytes(0, elements - 1);
+	map->memsize = BITS_TO_LONGS(elements) * sizeof(unsigned long);
 	set->variant = &bitmap_ipmac;
 	if (!init_map_ipmac(set, map, first_ip, last_ip, elements)) {
 		kfree(map);
diff --git a/net/netfilter/ipset/ip_set_bitmap_port.c b/net/netfilter/ipset/ip_set_bitmap_port.c
index 23d6095cb196..b49978dd810d 100644
--- a/net/netfilter/ipset/ip_set_bitmap_port.c
+++ b/net/netfilter/ipset/ip_set_bitmap_port.c
@@ -30,7 +30,7 @@ MODULE_ALIAS("ip_set_bitmap:port");
 
 /* Type structure */
 struct bitmap_port {
-	void *members;		/* the set members */
+	unsigned long *members;	/* the set members */
 	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 */
@@ -231,7 +231,7 @@ static bool
 init_map_port(struct ip_set *set, struct bitmap_port *map,
 	      u16 first_port, u16 last_port)
 {
-	map->members = ip_set_alloc(map->memsize);
+	map->members = bitmap_zalloc(map->elements, GFP_KERNEL | __GFP_NOWARN);
 	if (!map->members)
 		return false;
 	map->first_port = first_port;
@@ -271,7 +271,7 @@ bitmap_port_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
 		return -ENOMEM;
 
 	map->elements = elements;
-	map->memsize = bitmap_bytes(0, map->elements);
+	map->memsize = BITS_TO_LONGS(elements) * sizeof(unsigned long);
 	set->variant = &bitmap_port;
 	if (!init_map_port(set, map, first_port, last_port)) {
 		kfree(map);
-- 
2.20.1

Re: [PATCH 1/1] netfilter: ipset: use bitmap infrastructure completely

[Pablo Neira Ayuso]

On Sun, Jan 19, 2020 at 10:06:49PM +0100, Kadlecsik József wrote:
> The bitmap allocation did not use full unsigned long sizes
> when calculating the required size and that was triggered by KASAN
> as slab-out-of-bounds read in several places. The patch fixes all
> of them.

Applied, thanks Jozsef.