[PATCH AUTOSEL 4.18 17/59] netfilter: ipset: Fix calling ip_set() macro at dumping

Sasha Levin
2018-11-14T22:24:18Z

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

[ Upstream commit 8a02bdd50b2ecb6d62121d2958d3ea186cc88ce7 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 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 @@ ip_set_dump_start(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);
--
2.17.1