Merge: netfilter: ipset: Fix race between IPSET_CMD_CREATE and IPSET_CMD_SWAP

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/3400

JIRA: https://issues.redhat.com/browse/RHEL-5434
Upstream Status: commit 7433b6d
CVE: CVE-2023-42756

commit 7433b6d
Author: Jozsef Kadlecsik <kadlec@netfilter.org>
Date:   Tue Sep 19 20:04:45 2023 +0200

    netfilter: ipset: Fix race between IPSET_CMD_CREATE and IPSET_CMD_SWAP

    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: 24e2278 ("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: Phil Sutter <psutter@redhat.com>

Approved-by: Antoine Tenart <atenart@redhat.com>
Approved-by: Michal Schmidt <mschmidt@redhat.com>

Signed-off-by: Scott Weaver <scweaver@redhat.com>

Author: swvrrh

net/netfilter/ipset/ip_set_core.c

@@ -684,6 +684,14 @@ __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)
 {
@@ -1697,11 +1705,11 @@ 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);