netfilter: ipset: ipset list may return wrong member count for set with timeout

Simple testcase:

$ ipset create test hash:ip timeout 5
$ ipset add test 1.2.3.4
$ ipset add test 1.2.2.2
$ sleep 5

$ ipset l
Name: test
Type: hash:ip
Revision: 5
Header: family inet hashsize 1024 maxelem 65536 timeout 5
Size in memory: 296
References: 0
Number of entries: 2
Members:

We return "Number of entries: 2" but no members are listed. That is
because mtype_list runs "ip_set_timeout_expired" and does not list the
expired entries, but set->elements is never upated (until mtype_gc
cleans it up later).

Reviewed-by: Joshua Hunt <johunt@akamai.com>
Signed-off-by: Vishwanath Pai <vpai@akamai.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Vishwanath Pai 2017-09-11 21:52:40 +02:00 committed by Pablo Neira Ayuso
parent b0ade85165
commit 7f4f7dd441
1 changed files with 13 additions and 1 deletions

View File

@ -1041,12 +1041,24 @@ out:
static int
mtype_head(struct ip_set *set, struct sk_buff *skb)
{
const struct htype *h = set->data;
struct htype *h = set->data;
const struct htable *t;
struct nlattr *nested;
size_t memsize;
u8 htable_bits;
/* If any members have expired, set->elements will be wrong
* mytype_expire function will update it with the right count.
* we do not hold set->lock here, so grab it first.
* set->elements can still be incorrect in the case of a huge set,
* because elements might time out during the listing.
*/
if (SET_WITH_TIMEOUT(set)) {
spin_lock_bh(&set->lock);
mtype_expire(set, h);
spin_unlock_bh(&set->lock);
}
rcu_read_lock_bh();
t = rcu_dereference_bh_nfnl(h->table);
memsize = mtype_ahash_memsize(h, t) + set->ext_size;