From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
This patch fixes an oops that can be triggered following this recipe:
0) make sure nf_conntrack_netlink and nf_conntrack_ipv4 are loaded.
1) container is started.
2) connect to it via lxc-console.
3) generate some traffic with the container to create some conntrack
entries in its table.
4) stop the container: you hit one oops because the conntrack table
cleanup tries to report the destroy event to user-space but the
per-netns nfnetlink socket has already gone (as the nfnetlink
socket is per-netns but event callback registration is global).
To fix this situation, we make the ctnl_notifier per-netns so the
callback is registered/unregistered if the container is
created/destroyed.
Alex Bligh and Alexey Dobriyan originally proposed one small patch to
check if the nfnetlink socket is gone in nfnetlink_has_listeners,
but this is a very visited path for events, thus, it may reduce
performance and it looks a bit hackish to check for the nfnetlink
socket only to workaround this situation. As a result, I decided
to follow the bigger path choice, which seems to look nicer to me.
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Reported-by: Alex Bligh <alex@xxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/net/netfilter/nf_conntrack_ecache.h | 19 ++++---
include/net/netns/conntrack.h | 2 +
net/netfilter/nf_conntrack_ecache.c | 37 +++++++-------
net/netfilter/nf_conntrack_netlink.c | 73 +++++++++++++++++++--------
4 files changed, 82 insertions(+), 49 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_ecache.h b/include/net/netfilter/nf_conntrack_ecache.h
index 4283508..a88fb69 100644
--- a/include/net/netfilter/nf_conntrack_ecache.h
+++ b/include/net/netfilter/nf_conntrack_ecache.h
@@ -67,18 +67,18 @@ struct nf_ct_event_notifier {
int (*fcn)(unsigned int events, struct nf_ct_event *item);
};
-extern struct nf_ct_event_notifier __rcu *nf_conntrack_event_cb;
-extern int nf_conntrack_register_notifier(struct nf_ct_event_notifier *nb);
-extern void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *nb);
+extern int nf_conntrack_register_notifier(struct net *net, struct nf_ct_event_notifier *nb);
+extern void nf_conntrack_unregister_notifier(struct net *net, struct nf_ct_event_notifier *nb);
extern void nf_ct_deliver_cached_events(struct nf_conn *ct);
static inline void
nf_conntrack_event_cache(enum ip_conntrack_events event, struct nf_conn *ct)
{
+ struct net *net = nf_ct_net(ct);
struct nf_conntrack_ecache *e;
- if (nf_conntrack_event_cb == NULL)
+ if (net->ct.nf_conntrack_event_cb == NULL)
return;
e = nf_ct_ecache_find(ct);
@@ -95,11 +95,12 @@ nf_conntrack_eventmask_report(unsigned int eventmask,
int report)
{
int ret = 0;
+ struct net *net = nf_ct_net(ct);
struct nf_ct_event_notifier *notify;
struct nf_conntrack_ecache *e;
rcu_read_lock();
- notify = rcu_dereference(nf_conntrack_event_cb);
+ notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
if (notify == NULL)
goto out_unlock;
@@ -164,9 +165,8 @@ struct nf_exp_event_notifier {
int (*fcn)(unsigned int events, struct nf_exp_event *item);
};
-extern struct nf_exp_event_notifier __rcu *nf_expect_event_cb;
-extern int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *nb);
-extern void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *nb);
+extern int nf_ct_expect_register_notifier(struct net *net, struct nf_exp_event_notifier *nb);
+extern void nf_ct_expect_unregister_notifier(struct net *net, struct nf_exp_event_notifier *nb);
static inline void
nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
@@ -174,11 +174,12 @@ nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
u32 pid,
int report)
{
+ struct net *net = nf_ct_exp_net(exp);
struct nf_exp_event_notifier *notify;
struct nf_conntrack_ecache *e;
rcu_read_lock();
- notify = rcu_dereference(nf_expect_event_cb);
+ notify = rcu_dereference(net->ct.nf_expect_event_cb);
if (notify == NULL)
goto out_unlock;
diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h
index 0249399..7a911ec 100644
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -18,6 +18,8 @@ struct netns_ct {
struct hlist_nulls_head unconfirmed;
struct hlist_nulls_head dying;
struct ip_conntrack_stat __percpu *stat;
+ struct nf_ct_event_notifier __rcu *nf_conntrack_event_cb;
+ struct nf_exp_event_notifier __rcu *nf_expect_event_cb;
int sysctl_events;
unsigned int sysctl_events_retry_timeout;
int sysctl_acct;
diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c
index 6b368be..b62c414 100644
--- a/net/netfilter/nf_conntrack_ecache.c
+++ b/net/netfilter/nf_conntrack_ecache.c
@@ -27,22 +27,17 @@
static DEFINE_MUTEX(nf_ct_ecache_mutex);
-struct nf_ct_event_notifier __rcu *nf_conntrack_event_cb __read_mostly;
-EXPORT_SYMBOL_GPL(nf_conntrack_event_cb);
-
-struct nf_exp_event_notifier __rcu *nf_expect_event_cb __read_mostly;
-EXPORT_SYMBOL_GPL(nf_expect_event_cb);
-
/* deliver cached events and clear cache entry - must be called with locally
* disabled softirqs */
void nf_ct_deliver_cached_events(struct nf_conn *ct)
{
+ struct net *net = nf_ct_net(ct);
unsigned long events;
struct nf_ct_event_notifier *notify;
struct nf_conntrack_ecache *e;
rcu_read_lock();
- notify = rcu_dereference(nf_conntrack_event_cb);
+ notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
if (notify == NULL)
goto out_unlock;
@@ -83,19 +78,20 @@ out_unlock:
}
EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
-int nf_conntrack_register_notifier(struct nf_ct_event_notifier *new)
+int nf_conntrack_register_notifier(struct net *net,
+ struct nf_ct_event_notifier *new)
{
int ret = 0;
struct nf_ct_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
- notify = rcu_dereference_protected(nf_conntrack_event_cb,
+ notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
lockdep_is_held(&nf_ct_ecache_mutex));
if (notify != NULL) {
ret = -EBUSY;
goto out_unlock;
}
- RCU_INIT_POINTER(nf_conntrack_event_cb, new);
+ RCU_INIT_POINTER(net->ct.nf_conntrack_event_cb, new);
mutex_unlock(&nf_ct_ecache_mutex);
return ret;
@@ -105,32 +101,34 @@ out_unlock:
}
EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
-void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *new)
+void nf_conntrack_unregister_notifier(struct net *net,
+ struct nf_ct_event_notifier *new)
{
struct nf_ct_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
- notify = rcu_dereference_protected(nf_conntrack_event_cb,
+ notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
lockdep_is_held(&nf_ct_ecache_mutex));
BUG_ON(notify != new);
- RCU_INIT_POINTER(nf_conntrack_event_cb, NULL);
+ RCU_INIT_POINTER(net->ct.nf_conntrack_event_cb, NULL);
mutex_unlock(&nf_ct_ecache_mutex);
}
EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier);
-int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *new)
+int nf_ct_expect_register_notifier(struct net *net,
+ struct nf_exp_event_notifier *new)
{
int ret = 0;
struct nf_exp_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
- notify = rcu_dereference_protected(nf_expect_event_cb,
+ notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
lockdep_is_held(&nf_ct_ecache_mutex));
if (notify != NULL) {
ret = -EBUSY;
goto out_unlock;
}
- RCU_INIT_POINTER(nf_expect_event_cb, new);
+ RCU_INIT_POINTER(net->ct.nf_expect_event_cb, new);
mutex_unlock(&nf_ct_ecache_mutex);
return ret;
@@ -140,15 +138,16 @@ out_unlock:
}
EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier);
-void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *new)
+void nf_ct_expect_unregister_notifier(struct net *net,
+ struct nf_exp_event_notifier *new)
{
struct nf_exp_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
- notify = rcu_dereference_protected(nf_expect_event_cb,
+ notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
lockdep_is_held(&nf_ct_ecache_mutex));
BUG_ON(notify != new);
- RCU_INIT_POINTER(nf_expect_event_cb, NULL);
+ RCU_INIT_POINTER(net->ct.nf_expect_event_cb, NULL);
mutex_unlock(&nf_ct_ecache_mutex);
}
EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index e58aa9b..ef21b22 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -4,7 +4,7 @@
* (C) 2001 by Jay Schulist <jschlst@xxxxxxxxx>
* (C) 2002-2006 by Harald Welte <laforge@xxxxxxxxxxxx>
* (C) 2003 by Patrick Mchardy <kaber@xxxxxxxxx>
- * (C) 2005-2008 by Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
+ * (C) 2005-2011 by Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
*
* Initial connection tracking via netlink development funded and
* generally made possible by Network Robots, Inc. (www.networkrobots.com)
@@ -2163,6 +2163,54 @@ MODULE_ALIAS("ip_conntrack_netlink");
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK);
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_EXP);
+static int __net_init ctnetlink_net_init(struct net *net)
+{
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+ int ret;
+
+ ret = nf_conntrack_register_notifier(net, &ctnl_notifier);
+ if (ret < 0) {
+ pr_err("ctnetlink_init: cannot register notifier.\n");
+ goto err_out;
+ }
+
+ ret = nf_ct_expect_register_notifier(net, &ctnl_notifier_exp);
+ if (ret < 0) {
+ pr_err("ctnetlink_init: cannot expect register notifier.\n");
+ goto err_unreg_notifier;
+ }
+#endif
+ return 0;
+
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+err_unreg_notifier:
+ nf_conntrack_unregister_notifier(net, &ctnl_notifier);
+err_out:
+ return ret;
+#endif
+}
+
+static void ctnetlink_net_exit(struct net *net)
+{
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+ nf_ct_expect_unregister_notifier(net, &ctnl_notifier_exp);
+ nf_conntrack_unregister_notifier(net, &ctnl_notifier);
+#endif
+}
+
+static void __net_exit ctnetlink_net_exit_batch(struct list_head *net_exit_list)
+{
+ struct net *net;
+
+ list_for_each_entry(net, net_exit_list, exit_list)
+ ctnetlink_net_exit(net);
+}
+
+static struct pernet_operations ctnetlink_net_ops = {
+ .init = ctnetlink_net_init,
+ .exit_batch = ctnetlink_net_exit_batch,
+};
+
static int __init ctnetlink_init(void)
{
int ret;
@@ -2180,28 +2228,15 @@ static int __init ctnetlink_init(void)
goto err_unreg_subsys;
}
-#ifdef CONFIG_NF_CONNTRACK_EVENTS
- ret = nf_conntrack_register_notifier(&ctnl_notifier);
- if (ret < 0) {
- pr_err("ctnetlink_init: cannot register notifier.\n");
+ if (register_pernet_subsys(&ctnetlink_net_ops)) {
+ pr_err("ctnetlink_init: cannot register pernet operations\n");
goto err_unreg_exp_subsys;
}
- ret = nf_ct_expect_register_notifier(&ctnl_notifier_exp);
- if (ret < 0) {
- pr_err("ctnetlink_init: cannot expect register notifier.\n");
- goto err_unreg_notifier;
- }
-#endif
-
return 0;
-#ifdef CONFIG_NF_CONNTRACK_EVENTS
-err_unreg_notifier:
- nf_conntrack_unregister_notifier(&ctnl_notifier);
err_unreg_exp_subsys:
nfnetlink_subsys_unregister(&ctnl_exp_subsys);
-#endif
err_unreg_subsys:
nfnetlink_subsys_unregister(&ctnl_subsys);
err_out:
@@ -2213,11 +2248,7 @@ static void __exit ctnetlink_exit(void)
pr_info("ctnetlink: unregistering from nfnetlink.\n");
nf_ct_remove_userspace_expectations();
-#ifdef CONFIG_NF_CONNTRACK_EVENTS
- nf_ct_expect_unregister_notifier(&ctnl_notifier_exp);
- nf_conntrack_unregister_notifier(&ctnl_notifier);
-#endif
-
+ unregister_pernet_subsys(&ctnetlink_net_ops);
nfnetlink_subsys_unregister(&ctnl_exp_subsys);
nfnetlink_subsys_unregister(&ctnl_subsys);
}
--
1.7.2.5
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