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Message-Id: <1458005282-24665-2-git-send-email-pablo@netfilter.org>
Date: Tue, 15 Mar 2016 02:27:45 +0100
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 01/18] netfilter: ipset: Fix set:list type crash when flush/dump set in parallel
From: Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>
Flushing/listing entries was not RCU safe, so parallel flush/dump
could lead to kernel crash. Bug reported by Deniz Eren.
Fixes netfilter bugzilla id #1050.
Signed-off-by: Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>
---
net/netfilter/ipset/ip_set_core.c | 3 ++
net/netfilter/ipset/ip_set_list_set.c | 55 ++++++++++++++++-------------------
2 files changed, 28 insertions(+), 30 deletions(-)
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 95db43f..7e6568c 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -985,6 +985,9 @@ static int ip_set_destroy(struct net *net, struct sock *ctnl,
if (unlikely(protocol_failed(attr)))
return -IPSET_ERR_PROTOCOL;
+ /* Must wait for flush to be really finished in list:set */
+ rcu_barrier();
+
/* Commands are serialized and references are
* protected by the ip_set_ref_lock.
* External systems (i.e. xt_set) must call
diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
index bbede95..24c6c19 100644
--- a/net/netfilter/ipset/ip_set_list_set.c
+++ b/net/netfilter/ipset/ip_set_list_set.c
@@ -30,6 +30,7 @@ MODULE_ALIAS("ip_set_list:set");
struct set_elem {
struct rcu_head rcu;
struct list_head list;
+ struct ip_set *set; /* Sigh, in order to cleanup reference */
ip_set_id_t id;
} __aligned(__alignof__(u64));
@@ -151,30 +152,29 @@ list_set_kadt(struct ip_set *set, const struct sk_buff *skb,
/* Userspace interfaces: we are protected by the nfnl mutex */
static void
-__list_set_del(struct ip_set *set, struct set_elem *e)
+__list_set_del_rcu(struct rcu_head * rcu)
{
+ struct set_elem *e = container_of(rcu, struct set_elem, rcu);
+ struct ip_set *set = e->set;
struct list_set *map = set->data;
ip_set_put_byindex(map->net, e->id);
- /* We may call it, because we don't have a to be destroyed
- * extension which is used by the kernel.
- */
ip_set_ext_destroy(set, e);
- kfree_rcu(e, rcu);
+ kfree(e);
}
static inline void
list_set_del(struct ip_set *set, struct set_elem *e)
{
list_del_rcu(&e->list);
- __list_set_del(set, e);
+ call_rcu(&e->rcu, __list_set_del_rcu);
}
static inline void
-list_set_replace(struct ip_set *set, struct set_elem *e, struct set_elem *old)
+list_set_replace(struct set_elem *e, struct set_elem *old)
{
list_replace_rcu(&old->list, &e->list);
- __list_set_del(set, old);
+ call_rcu(&old->rcu, __list_set_del_rcu);
}
static void
@@ -244,9 +244,6 @@ list_set_uadd(struct ip_set *set, void *value, const struct ip_set_ext *ext,
struct set_elem *e, *n, *prev, *next;
bool flag_exist = flags & IPSET_FLAG_EXIST;
- if (SET_WITH_TIMEOUT(set))
- set_cleanup_entries(set);
-
/* Find where to add the new entry */
n = prev = next = NULL;
list_for_each_entry(e, &map->members, list) {
@@ -301,10 +298,11 @@ list_set_uadd(struct ip_set *set, void *value, const struct ip_set_ext *ext,
if (!e)
return -ENOMEM;
e->id = d->id;
+ e->set = set;
INIT_LIST_HEAD(&e->list);
list_set_init_extensions(set, ext, e);
if (n)
- list_set_replace(set, e, n);
+ list_set_replace(e, n);
else if (next)
list_add_tail_rcu(&e->list, &next->list);
else if (prev)
@@ -431,6 +429,7 @@ list_set_destroy(struct ip_set *set)
if (SET_WITH_TIMEOUT(set))
del_timer_sync(&map->gc);
+
list_for_each_entry_safe(e, n, &map->members, list) {
list_del(&e->list);
ip_set_put_byindex(map->net, e->id);
@@ -450,8 +449,10 @@ list_set_head(struct ip_set *set, struct sk_buff *skb)
struct set_elem *e;
u32 n = 0;
- list_for_each_entry(e, &map->members, list)
+ rcu_read_lock();
+ list_for_each_entry_rcu(e, &map->members, list)
n++;
+ rcu_read_unlock();
nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
if (!nested)
@@ -483,33 +484,25 @@ list_set_list(const struct ip_set *set,
atd = ipset_nest_start(skb, IPSET_ATTR_ADT);
if (!atd)
return -EMSGSIZE;
- list_for_each_entry(e, &map->members, list) {
- if (i == first)
- break;
- i++;
- }
rcu_read_lock();
- list_for_each_entry_from(e, &map->members, list) {
- i++;
- if (SET_WITH_TIMEOUT(set) &&
- ip_set_timeout_expired(ext_timeout(e, set)))
+ list_for_each_entry_rcu(e, &map->members, list) {
+ if (i < first ||
+ (SET_WITH_TIMEOUT(set) &&
+ ip_set_timeout_expired(ext_timeout(e, set)))) {
+ i++;
continue;
+ }
nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
- if (!nested) {
- if (i == first) {
- nla_nest_cancel(skb, atd);
- ret = -EMSGSIZE;
- goto out;
- }
+ if (!nested)
goto nla_put_failure;
- }
if (nla_put_string(skb, IPSET_ATTR_NAME,
ip_set_name_byindex(map->net, e->id)))
goto nla_put_failure;
if (ip_set_put_extensions(skb, set, e, true))
goto nla_put_failure;
ipset_nest_end(skb, nested);
+ i++;
}
ipset_nest_end(skb, atd);
@@ -520,10 +513,12 @@ list_set_list(const struct ip_set *set,
nla_put_failure:
nla_nest_cancel(skb, nested);
if (unlikely(i == first)) {
+ nla_nest_cancel(skb, atd);
cb->args[IPSET_CB_ARG0] = 0;
ret = -EMSGSIZE;
+ } else {
+ cb->args[IPSET_CB_ARG0] = i;
}
- cb->args[IPSET_CB_ARG0] = i - 1;
ipset_nest_end(skb, atd);
out:
rcu_read_unlock();
--
2.1.4
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