From: Jozsef Kadlecsik <kad...@blackhole.kfki.hu>

The ip_set() macro is called when either ip_set_ref_lock held only
or no lock/nfnl mutex is held at dumping. Take this into account
properly. Also, use Pablo's suggestion to use rcu_dereference_raw(),
the ref_netlink protects the set.

Signed-off-by: Jozsef Kadlecsik <kad...@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>

(cherry-picked from commit 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7)
https://jira.sw.ru/browse/PSBM-122965
Signed-off-by: Vasily Averin <v...@virtuozzo.com>
---
 net/netfilter/ipset/ip_set_core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_core.c 
b/net/netfilter/ipset/ip_set_core.c
index a22af3e..b067879 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -55,11 +55,15 @@ MODULE_AUTHOR("Jozsef Kadlecsik 
<kad...@blackhole.kfki.hu>");
 MODULE_DESCRIPTION("core IP set support");
 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_IPSET);
 
-/* When the nfnl mutex is held: */
+/* When the nfnl mutex or ip_set_ref_lock is held: */
 #define ip_set_dereference(p)          \
-       rcu_dereference_protected(p, lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET))
+       rcu_dereference_protected(p,    \
+               lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET) || \
+               lockdep_is_held(&ip_set_ref_lock))
 #define ip_set(inst, id)               \
        ip_set_dereference((inst)->ip_set_list)[id]
+#define ip_set_ref_netlink(inst,id)    \
+       rcu_dereference_raw((inst)->ip_set_list)[id]
 
 /* The set types are implemented in modules and registered set types
  * can be found in ip_set_type_list. Adding/deleting types is
@@ -1261,7 +1265,7 @@ ip_set_dump_done(struct netlink_callback *cb)
                struct ip_set_net *inst =
                        (struct ip_set_net *)cb->args[IPSET_CB_NET];
                ip_set_id_t index = (ip_set_id_t)cb->args[IPSET_CB_INDEX];
-               struct ip_set *set = ip_set(inst, index);
+               struct ip_set *set = ip_set_ref_netlink(inst, index);
 
                if (set->variant->uref)
                        set->variant->uref(set, cb, false);
@@ -1457,7 +1461,7 @@ ip_set_dump_do(struct sk_buff *skb, struct 
netlink_callback *cb)
 release_refcount:
        /* If there was an error or set is done, release set */
        if (ret || !cb->args[IPSET_CB_ARG0]) {
-               set = ip_set(inst, index);
+               set = ip_set_ref_netlink(inst, index);
                if (set->variant->uref)
                        set->variant->uref(set, cb, false);
                pr_debug("release set %s\n", set->name);
-- 
1.8.3.1

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