netfilter: ipset: Fix calling ip_set() macro at dumping

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 <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 68db946df151..1577f2f76060 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 <kadlec@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
@@ -1251,7 +1255,7 @@ 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);
@@ -1440,7 +1444,7 @@ next_set:
 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);