5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jozsef Kadlecsik kadlec@netfilter.org
[ Upstream commit 7433b6d2afd512d04398c73aa984d1e285be125b ]
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@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 --- 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 1cf143f5df2e9..d3be0d0b0bdad 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -530,6 +530,14 @@ __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 inline void __ip_set_put_netlink(struct ip_set *set) { @@ -1529,11 +1537,11 @@ call_ad(struct sock *ctnl, struct sk_buff *skb, struct ip_set *set,
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);