Kyle Zeng reported that there is a race between IPSET_CMD_ADD and IPSET_CMD_SWAP
in netfilter/ip_set, which can lead to the invocation of `__ip_set_put` on a wrong
`set`, triggering the `BUG_ON(set->ref == 0);` check in it.
The race is caused by using the wrong reference counter, i.e. the ref counter instead
of ref_netlink.
Fixes: 24e227896bbf ("netfilter: ipset: Add schedule point in call_ad().")
Reported-by: Kyle Zeng <zengyhkyle@xxxxxxxxx>
Tested-by: Kyle Zeng <zengyhkyle@xxxxxxxxx>
Signed-off-by: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>
---
net/netfilter/ipset/ip_set_core.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index e564b5174261..35d2f9c9ada0 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -682,6 +682,14 @@ __ip_set_put(struct ip_set *set)
/* set->ref can be swapped out by ip_set_swap, netlink events (like dump) need
* a separate reference counter
*/
+static void
+__ip_set_get_netlink(struct ip_set *set)
+{
+ write_lock_bh(&ip_set_ref_lock);
+ set->ref_netlink++;
+ write_unlock_bh(&ip_set_ref_lock);
+}
+
static void
__ip_set_put_netlink(struct ip_set *set)
{
@@ -1693,11 +1701,11 @@ call_ad(struct net *net, struct sock *ctnl, struct sk_buff *skb,
do {
if (retried) {
- __ip_set_get(set);
+ __ip_set_get_netlink(set);
nfnl_unlock(NFNL_SUBSYS_IPSET);
cond_resched();
nfnl_lock(NFNL_SUBSYS_IPSET);
- __ip_set_put(set);
+ __ip_set_put_netlink(set);
}
ip_set_lock(set);
--
2.30.2
