netfilter: ipset: Limit the maximal range of consecutive elements to add/delete

[ Upstream commit 5f7b51bf09baca8e4f80cbe879536842bafb5f31 ]

The range size of consecutive elements were not limited. Thus one could
define a huge range which may result soft lockup errors due to the long
execution time. Now the range size is limited to 2^20 entries.

Reported-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stable-dep-of: c7aa1a76d4a0 ("netfilter: ipset: regression in ip_set_hash_ip.c")
Signed-off-by: Sasha Levin <sashal@kernel.org>

include/linux/netfilter/ipset/ip_set.h

@@ -198,6 +198,9 @@ struct ip_set_region {
 	u32 elements;		/* Number of elements vs timeout */
 };
 
+/* Max range where every element is added/deleted in one step */
+#define IPSET_MAX_RANGE		(1<<20)
+
 /* The core set type structure */
 struct ip_set_type {
 	struct list_head list;