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netfilter: ipset: Fix race between IPSET_CMD_CREATE and IPSET_CMD_SWAP

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[ Upstream commit 7433b6d2af ]

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: 24e227896b ("netfilter: ipset: Add schedule point in call_ad().")
Reported-by: Kyle Zeng <zengyhkyle@gmail.com>
Closes: https://lore.kernel.org/netfilter-devel/ZPZqetxOmH+w%2Fmyc@westworld/#r
Tested-by: Kyle Zeng <zengyhkyle@gmail.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jozsef Kadlecsik 2023-09-19 20:04:45 +02:00 committed by Greg Kroah-Hartman
parent 0dcc9b4097
commit a70dbdede0
1 changed files with 10 additions and 2 deletions
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12
net/netfilter/ipset/ip_set_core.c
View file

@ -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)
{
@ -1695,11 +1703,11 @@ 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);