netfilter: ipset: Add support for new bitmask parameter

Add a new parameter to complement the existing 'netmask' option. The
main difference between netmask and bitmask is that bitmask takes any
arbitrary ip address as input, it does not have to be a valid netmask.

The name of the new parameter is 'bitmask'. This lets us mask out
arbitrary bits in the ip address, for example:
ipset create set1 hash:ip bitmask 255.128.255.0
ipset create set2 hash:ip,port family inet6 bitmask ffff::ff80
Signed-off-by: NVishwanath Pai <vpai@akamai.com>
Signed-off-by: NJoshua Hunt <johunt@akamai.com>
Signed-off-by: NJozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

include/linux/netfilter/ipset/ip_set.h

@@ -515,6 +515,16 @@ ip_set_init_skbinfo(struct ip_set_skbinfo *skbinfo,
 	*skbinfo = ext->skbinfo;
 }
 
+static inline void
+nf_inet_addr_mask_inplace(union nf_inet_addr *a1,
+			  const union nf_inet_addr *mask)
+{
+	a1->all[0] &= mask->all[0];
+	a1->all[1] &= mask->all[1];
+	a1->all[2] &= mask->all[2];
+	a1->all[3] &= mask->all[3];
+}
+
 #define IP_SET_INIT_KEXT(skb, opt, set)			\
 	{ .bytes = (skb)->len, .packets = 1, .target = true,\
 	  .timeout = ip_set_adt_opt_timeout(opt, set) }

include/uapi/linux/netfilter/ipset/ip_set.h

@@ -85,6 +85,7 @@ enum {
 	IPSET_ATTR_CADT_LINENO = IPSET_ATTR_LINENO,	/* 9 */
 	IPSET_ATTR_MARK,	/* 10 */
 	IPSET_ATTR_MARKMASK,	/* 11 */
+	IPSET_ATTR_BITMASK,	/* 12 */
 	/* Reserve empty slots */
 	IPSET_ATTR_CADT_MAX = 16,
 	/* Create-only specific attributes */
@@ -153,6 +154,7 @@ enum ipset_errno {
 	IPSET_ERR_COMMENT,
 	IPSET_ERR_INVALID_MARKMASK,
 	IPSET_ERR_SKBINFO,
+	IPSET_ERR_BITMASK_NETMASK_EXCL,
 
 	/* Type specific error codes */
 	IPSET_ERR_TYPE_SPECIFIC = 4352,

net/netfilter/ipset/ip_set_hash_gen.h

@@ -159,6 +159,17 @@ htable_size(u8 hbits)
 	(SET_WITH_TIMEOUT(set) &&	\
 	 ip_set_timeout_expired(ext_timeout(d, set)))
 
+#if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
+static const union nf_inet_addr onesmask = {
+	.all[0] = 0xffffffff,
+	.all[1] = 0xffffffff,
+	.all[2] = 0xffffffff,
+	.all[3] = 0xffffffff
+};
+
+static const union nf_inet_addr zeromask = {};
+#endif
+
 #endif /* _IP_SET_HASH_GEN_H */
 
 #ifndef MTYPE
@@ -283,8 +294,9 @@ struct htype {
 	u32 markmask;		/* markmask value for mark mask to store */
 #endif
 	u8 bucketsize;		/* max elements in an array block */
-#ifdef IP_SET_HASH_WITH_NETMASK
+#if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
 	u8 netmask;		/* netmask value for subnets to store */
+	union nf_inet_addr bitmask;	/* stores bitmask */
 #endif
 	struct list_head ad;	/* Resize add|del backlist */
 	struct mtype_elem next; /* temporary storage for uadd */
@@ -459,8 +471,8 @@ mtype_same_set(const struct ip_set *a, const struct ip_set *b)
 	/* Resizing changes htable_bits, so we ignore it */
 	return x->maxelem == y->maxelem &&
 	       a->timeout == b->timeout &&
-#ifdef IP_SET_HASH_WITH_NETMASK
-	       x->netmask == y->netmask &&
+#if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
+	       nf_inet_addr_cmp(&x->bitmask, &y->bitmask) &&
 #endif
 #ifdef IP_SET_HASH_WITH_MARKMASK
 	       x->markmask == y->markmask &&
@@ -1264,9 +1276,21 @@ mtype_head(struct ip_set *set, struct sk_buff *skb)
 			  htonl(jhash_size(htable_bits))) ||
 	    nla_put_net32(skb, IPSET_ATTR_MAXELEM, htonl(h->maxelem)))
 		goto nla_put_failure;
+#ifdef IP_SET_HASH_WITH_BITMASK
+	/* if netmask is set to anything other than HOST_MASK we know that the user supplied netmask
+	 * and not bitmask. These two are mutually exclusive. */
+	if (h->netmask == HOST_MASK && !nf_inet_addr_cmp(&onesmask, &h->bitmask)) {
+		if (set->family == NFPROTO_IPV4) {
+			if (nla_put_ipaddr4(skb, IPSET_ATTR_BITMASK, h->bitmask.ip))
+				goto nla_put_failure;
+		} else if (set->family == NFPROTO_IPV6) {
+			if (nla_put_ipaddr6(skb, IPSET_ATTR_BITMASK, &h->bitmask.in6))
+				goto nla_put_failure;
+		}
+	}
+#endif
 #ifdef IP_SET_HASH_WITH_NETMASK
-	if (h->netmask != HOST_MASK &&
-	    nla_put_u8(skb, IPSET_ATTR_NETMASK, h->netmask))
+	if (h->netmask != HOST_MASK && nla_put_u8(skb, IPSET_ATTR_NETMASK, h->netmask))
 		goto nla_put_failure;
 #endif
 #ifdef IP_SET_HASH_WITH_MARKMASK
@@ -1429,8 +1453,10 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 	u32 markmask;
 #endif
 	u8 hbits;
-#ifdef IP_SET_HASH_WITH_NETMASK
-	u8 netmask;
+#if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
+	int ret __attribute__((unused)) = 0;
+	u8 netmask = set->family == NFPROTO_IPV4 ? 32 : 128;
+	union nf_inet_addr bitmask = onesmask;
 #endif
 	size_t hsize;
 	struct htype *h;
@@ -1468,7 +1494,6 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 #endif
 
 #ifdef IP_SET_HASH_WITH_NETMASK
-	netmask = set->family == NFPROTO_IPV4 ? 32 : 128;
 	if (tb[IPSET_ATTR_NETMASK]) {
 		netmask = nla_get_u8(tb[IPSET_ATTR_NETMASK]);
 
@@ -1476,6 +1501,33 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 		    (set->family == NFPROTO_IPV6 && netmask > 128) ||
 		    netmask == 0)
 			return -IPSET_ERR_INVALID_NETMASK;
+
+		/* we convert netmask to bitmask and store it */
+		if (set->family == NFPROTO_IPV4)
+			bitmask.ip = ip_set_netmask(netmask);
+		else
+			ip6_netmask(&bitmask, netmask);
+	}
+#endif
+
+#ifdef IP_SET_HASH_WITH_BITMASK
+	if (tb[IPSET_ATTR_BITMASK]) {
+		/* bitmask and netmask do the same thing, allow only one of these options */
+		if (tb[IPSET_ATTR_NETMASK])
+			return -IPSET_ERR_BITMASK_NETMASK_EXCL;
+
+		if (set->family == NFPROTO_IPV4) {
+			ret = ip_set_get_ipaddr4(tb[IPSET_ATTR_BITMASK], &bitmask.ip);
+			if (ret || !bitmask.ip)
+				return -IPSET_ERR_INVALID_NETMASK;
+		} else if (set->family == NFPROTO_IPV6) {
+			ret = ip_set_get_ipaddr6(tb[IPSET_ATTR_BITMASK], &bitmask);
+			if (ret || ipv6_addr_any(&bitmask.in6))
+				return -IPSET_ERR_INVALID_NETMASK;
+		}
+
+		if (nf_inet_addr_cmp(&bitmask, &zeromask))
+			return -IPSET_ERR_INVALID_NETMASK;
 	}
 #endif
 
@@ -1518,7 +1570,8 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 	for (i = 0; i < ahash_numof_locks(hbits); i++)
 		spin_lock_init(&t->hregion[i].lock);
 	h->maxelem = maxelem;
-#ifdef IP_SET_HASH_WITH_NETMASK
+#if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
+	h->bitmask = bitmask;
 	h->netmask = netmask;
 #endif
 #ifdef IP_SET_HASH_WITH_MARKMASK

net/netfilter/ipset/ip_set_hash_ip.c

@@ -24,7 +24,8 @@
 /*				2	   Comments support */
 /*				3	   Forceadd support */
 /*				4	   skbinfo support */
-#define IPSET_TYPE_REV_MAX	5	/* bucketsize, initval support  */
+/*				5	   bucketsize, initval support  */
+#define IPSET_TYPE_REV_MAX	6	/* bitmask support  */
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@netfilter.org>");
@@ -34,6 +35,7 @@ MODULE_ALIAS("ip_set_hash:ip");
 /* Type specific function prefix */
 #define HTYPE		hash_ip
 #define IP_SET_HASH_WITH_NETMASK
+#define IP_SET_HASH_WITH_BITMASK
 
 /* IPv4 variant */
 
@@ -86,7 +88,7 @@ hash_ip4_kadt(struct ip_set *set, const struct sk_buff *skb,
 	__be32 ip;
 
 	ip4addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &ip);
-	ip &= ip_set_netmask(h->netmask);
+	ip &= h->bitmask.ip;
 	if (ip == 0)
 		return -EINVAL;
 
@@ -119,7 +121,7 @@ hash_ip4_uadt(struct ip_set *set, struct nlattr *tb[],
 	if (ret)
 		return ret;
 
-	ip &= ip_set_hostmask(h->netmask);
+	ip &= ntohl(h->bitmask.ip);
 	e.ip = htonl(ip);
 	if (e.ip == 0)
 		return -IPSET_ERR_HASH_ELEM;
@@ -187,12 +189,6 @@ hash_ip6_data_equal(const struct hash_ip6_elem *ip1,
 	return ipv6_addr_equal(&ip1->ip.in6, &ip2->ip.in6);
 }
 
-static void
-hash_ip6_netmask(union nf_inet_addr *ip, u8 prefix)
-{
-	ip6_netmask(ip, prefix);
-}
-
 static bool
 hash_ip6_data_list(struct sk_buff *skb, const struct hash_ip6_elem *e)
 {
@@ -229,7 +225,7 @@ hash_ip6_kadt(struct ip_set *set, const struct sk_buff *skb,
 	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
 
 	ip6addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip.in6);
-	hash_ip6_netmask(&e.ip, h->netmask);
+	nf_inet_addr_mask_inplace(&e.ip, &h->bitmask);
 	if (ipv6_addr_any(&e.ip.in6))
 		return -EINVAL;
 
@@ -268,7 +264,7 @@ hash_ip6_uadt(struct ip_set *set, struct nlattr *tb[],
 	if (ret)
 		return ret;
 
-	hash_ip6_netmask(&e.ip, h->netmask);
+	nf_inet_addr_mask_inplace(&e.ip, &h->bitmask);
 	if (ipv6_addr_any(&e.ip.in6))
 		return -IPSET_ERR_HASH_ELEM;
 
@@ -295,6 +291,7 @@ static struct ip_set_type hash_ip_type __read_mostly = {
 		[IPSET_ATTR_RESIZE]	= { .type = NLA_U8  },
 		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
 		[IPSET_ATTR_NETMASK]	= { .type = NLA_U8  },
+		[IPSET_ATTR_BITMASK]	= { .type = NLA_NESTED },
 		[IPSET_ATTR_CADT_FLAGS]	= { .type = NLA_U32 },
 	},
 	.adt_policy	= {

net/netfilter/ipset/ip_set_hash_ipport.c

@@ -26,7 +26,8 @@
 /*				3    Comments support added */
 /*				4    Forceadd support added */
 /*				5    skbinfo support added */
-#define IPSET_TYPE_REV_MAX	6 /* bucketsize, initval support added */
+/*				6    bucketsize, initval support added */
+#define IPSET_TYPE_REV_MAX	7 /* bitmask support added */
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@netfilter.org>");
@@ -35,6 +36,8 @@ MODULE_ALIAS("ip_set_hash:ip,port");
 
 /* Type specific function prefix */
 #define HTYPE		hash_ipport
+#define IP_SET_HASH_WITH_NETMASK
+#define IP_SET_HASH_WITH_BITMASK
 
 /* IPv4 variant */
 
@@ -92,12 +95,16 @@ hash_ipport4_kadt(struct ip_set *set, const struct sk_buff *skb,
 	ipset_adtfn adtfn = set->variant->adt[adt];
 	struct hash_ipport4_elem e = { .ip = 0 };
 	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
+	const struct MTYPE *h = set->data;
 
 	if (!ip_set_get_ip4_port(skb, opt->flags & IPSET_DIM_TWO_SRC,
 				 &e.port, &e.proto))
 		return -EINVAL;
 
 	ip4addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip);
+	e.ip &= h->bitmask.ip;
+	if (e.ip == 0)
+		return -EINVAL;
 	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
 }
 
@@ -129,6 +136,10 @@ hash_ipport4_uadt(struct ip_set *set, struct nlattr *tb[],
 	if (ret)
 		return ret;
 
+	e.ip &= h->bitmask.ip;
+	if (e.ip == 0)
+		return -EINVAL;
+
 	e.port = nla_get_be16(tb[IPSET_ATTR_PORT]);
 
 	if (tb[IPSET_ATTR_PROTO]) {
@@ -253,12 +264,17 @@ hash_ipport6_kadt(struct ip_set *set, const struct sk_buff *skb,
 	ipset_adtfn adtfn = set->variant->adt[adt];
 	struct hash_ipport6_elem e = { .ip = { .all = { 0 } } };
 	struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
+	const struct MTYPE *h = set->data;
 
 	if (!ip_set_get_ip6_port(skb, opt->flags & IPSET_DIM_TWO_SRC,
 				 &e.port, &e.proto))
 		return -EINVAL;
 
 	ip6addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip.in6);
+	nf_inet_addr_mask_inplace(&e.ip, &h->bitmask);
+	if (ipv6_addr_any(&e.ip.in6))
+		return -EINVAL;
+
 	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
 }
 
@@ -298,6 +314,10 @@ hash_ipport6_uadt(struct ip_set *set, struct nlattr *tb[],
 	if (ret)
 		return ret;
 
+	nf_inet_addr_mask_inplace(&e.ip, &h->bitmask);
+	if (ipv6_addr_any(&e.ip.in6))
+		return -EINVAL;
+
 	e.port = nla_get_be16(tb[IPSET_ATTR_PORT]);
 
 	if (tb[IPSET_ATTR_PROTO]) {
@@ -356,6 +376,8 @@ static struct ip_set_type hash_ipport_type __read_mostly = {
 		[IPSET_ATTR_PROTO]	= { .type = NLA_U8 },
 		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
 		[IPSET_ATTR_CADT_FLAGS]	= { .type = NLA_U32 },
+		[IPSET_ATTR_NETMASK]	= { .type = NLA_U8 },
+		[IPSET_ATTR_BITMASK]	= { .type = NLA_NESTED },
 	},
 	.adt_policy	= {
 		[IPSET_ATTR_IP]		= { .type = NLA_NESTED },

net/netfilter/ipset/ip_set_hash_netnet.c

@@ -23,7 +23,8 @@
 #define IPSET_TYPE_REV_MIN	0
 /*				1	   Forceadd support added */
 /*				2	   skbinfo support added */
-#define IPSET_TYPE_REV_MAX	3	/* bucketsize, initval support added */
+/*				3	   bucketsize, initval support added */
+#define IPSET_TYPE_REV_MAX	4	/* bitmask support added */
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Oliver Smith <oliver@8.c.9.b.0.7.4.0.1.0.0.2.ip6.arpa>");
@@ -33,6 +34,8 @@ MODULE_ALIAS("ip_set_hash:net,net");
 /* Type specific function prefix */
 #define HTYPE		hash_netnet
 #define IP_SET_HASH_WITH_NETS
+#define IP_SET_HASH_WITH_NETMASK
+#define IP_SET_HASH_WITH_BITMASK
 #define IPSET_NET_COUNT 2
 
 /* IPv4 variants */
@@ -153,8 +156,8 @@ hash_netnet4_kadt(struct ip_set *set, const struct sk_buff *skb,
 
 	ip4addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip[0]);
 	ip4addrptr(skb, opt->flags & IPSET_DIM_TWO_SRC, &e.ip[1]);
-	e.ip[0] &= ip_set_netmask(e.cidr[0]);
-	e.ip[1] &= ip_set_netmask(e.cidr[1]);
+	e.ip[0] &= (ip_set_netmask(e.cidr[0]) & h->bitmask.ip);
+	e.ip[1] &= (ip_set_netmask(e.cidr[1]) & h->bitmask.ip);
 
 	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
 }
@@ -213,8 +216,8 @@ hash_netnet4_uadt(struct ip_set *set, struct nlattr *tb[],
 
 	if (adt == IPSET_TEST || !(tb[IPSET_ATTR_IP_TO] ||
 				   tb[IPSET_ATTR_IP2_TO])) {
-		e.ip[0] = htonl(ip & ip_set_hostmask(e.cidr[0]));
-		e.ip[1] = htonl(ip2_from & ip_set_hostmask(e.cidr[1]));
+		e.ip[0] = htonl(ip & ntohl(h->bitmask.ip) & ip_set_hostmask(e.cidr[0]));
+		e.ip[1] = htonl(ip2_from & ntohl(h->bitmask.ip) & ip_set_hostmask(e.cidr[1]));
 		ret = adtfn(set, &e, &ext, &ext, flags);
 		return ip_set_enomatch(ret, flags, adt, set) ? -ret :
 		       ip_set_eexist(ret, flags) ? 0 : ret;
@@ -404,6 +407,11 @@ hash_netnet6_kadt(struct ip_set *set, const struct sk_buff *skb,
 	ip6_netmask(&e.ip[0], e.cidr[0]);
 	ip6_netmask(&e.ip[1], e.cidr[1]);
 
+	nf_inet_addr_mask_inplace(&e.ip[0], &h->bitmask);
+	nf_inet_addr_mask_inplace(&e.ip[1], &h->bitmask);
+	if (e.cidr[0] == HOST_MASK && ipv6_addr_any(&e.ip[0].in6))
+		return -EINVAL;
+
 	return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
 }
 
@@ -414,6 +422,7 @@ hash_netnet6_uadt(struct ip_set *set, struct nlattr *tb[],
 	ipset_adtfn adtfn = set->variant->adt[adt];
 	struct hash_netnet6_elem e = { };
 	struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
+	const struct hash_netnet6 *h = set->data;
 	int ret;
 
 	if (tb[IPSET_ATTR_LINENO])
@@ -453,6 +462,11 @@ hash_netnet6_uadt(struct ip_set *set, struct nlattr *tb[],
 	ip6_netmask(&e.ip[0], e.cidr[0]);
 	ip6_netmask(&e.ip[1], e.cidr[1]);
 
+	nf_inet_addr_mask_inplace(&e.ip[0], &h->bitmask);
+	nf_inet_addr_mask_inplace(&e.ip[1], &h->bitmask);
+	if (e.cidr[0] == HOST_MASK && ipv6_addr_any(&e.ip[0].in6))
+		return -IPSET_ERR_HASH_ELEM;
+
 	if (tb[IPSET_ATTR_CADT_FLAGS]) {
 		u32 cadt_flags = ip_set_get_h32(tb[IPSET_ATTR_CADT_FLAGS]);
 
@@ -484,6 +498,8 @@ static struct ip_set_type hash_netnet_type __read_mostly = {
 		[IPSET_ATTR_RESIZE]	= { .type = NLA_U8  },
 		[IPSET_ATTR_TIMEOUT]	= { .type = NLA_U32 },
 		[IPSET_ATTR_CADT_FLAGS]	= { .type = NLA_U32 },
+		[IPSET_ATTR_NETMASK]    = { .type = NLA_U8 },
+		[IPSET_ATTR_BITMASK]	= { .type = NLA_NESTED },
 	},
 	.adt_policy	= {
 		[IPSET_ATTR_IP]		= { .type = NLA_NESTED },