From c63afc87e554f3742b7c2cd9c401cefb632bb38a Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Mon, 18 Sep 2023 23:10:51 +0200 Subject: 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. Reported-by: Kyle Zeng Tested-by: Kyle Zeng Signed-off-by: Jozsef Kadlecsik --- kernel/net/netfilter/ipset/ip_set_core.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/net/netfilter/ipset/ip_set_core.c b/kernel/net/netfilter/ipset/ip_set_core.c index 1a647c5..484e798 100644 --- a/kernel/net/netfilter/ipset/ip_set_core.c +++ b/kernel/net/netfilter/ipset/ip_set_core.c @@ -683,6 +683,14 @@ __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) { @@ -1749,11 +1757,11 @@ 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); -- cgit v1.2.3