From 70e9942f17a6193e9172a804e6569a8806633d6b Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 22 Nov 2011 00:16:51 +0100 Subject: netfilter: nf_conntrack: make event callback registration per-netns 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 Reported-by: Alex Bligh Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_ecache.h | 19 ++++++++++--------- include/net/netns/conntrack.h | 2 ++ 2 files changed, 12 insertions(+), 9 deletions(-) (limited to 'include/net') diff --git a/include/net/netfilter/nf_conntrack_ecache.h b/include/net/netfilter/nf_conntrack_ecache.h index 4283508b3e18..a88fb6939387 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 0249399e51a7..7a911eca0f18 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; -- cgit v1.2.3