[PATCH net v2] netfilter: ipset: add missing range check in bitmap_ip_uadt

[Jeongjun Park <aha310510@gmail.com>]

When tb[IPSET_ATTR_IP_TO] is not present but tb[IPSET_ATTR_CIDR] exists,
the values of ip and ip_to are slightly swapped. Therefore, the range check
for ip should be done later, but this part is missing and it seems that the
vulnerability occurs.

So we should add missing range checks and remove unnecessary range checks.

Cc: <stable@vger.kernel.org>
Reported-by: syzbot+58c872f7790a4d2ac951@syzkaller.appspotmail.com
Fixes: 72205fc68bd1 ("netfilter: ipset: bitmap:ip set type support")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
---
 net/netfilter/ipset/ip_set_bitmap_ip.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_bitmap_ip.c b/net/netfilter/ipset/ip_set_bitmap_ip.c
index e4fa00abde6a..5988b9bb9029 100644
--- a/net/netfilter/ipset/ip_set_bitmap_ip.c
+++ b/net/netfilter/ipset/ip_set_bitmap_ip.c
@@ -163,11 +163,8 @@ bitmap_ip_uadt(struct ip_set *set, struct nlattr *tb[],
 		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP_TO], &ip_to);
 		if (ret)
 			return ret;
-		if (ip > ip_to) {
+		if (ip > ip_to)
 			swap(ip, ip_to);
-			if (ip < map->first_ip)
-				return -IPSET_ERR_BITMAP_RANGE;
-		}
 	} else if (tb[IPSET_ATTR_CIDR]) {
 		u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
 
@@ -178,7 +175,7 @@ bitmap_ip_uadt(struct ip_set *set, struct nlattr *tb[],
 		ip_to = ip;
 	}
 
-	if (ip_to > map->last_ip)
+	if (ip < map->first_ip || ip_to > map->last_ip)
 		return -IPSET_ERR_BITMAP_RANGE;
 
 	for (; !before(ip_to, ip); ip += map->hosts) {
--