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authorPablo Neira Ayuso <pablo@netfilter.org>2012-08-29 16:25:49 +0000
committerBen Hutchings <ben@decadent.org.uk>2012-10-30 23:27:08 +0000
commitcc1b75d796ad050c83c95733c4220aaa04fa1304 (patch)
treeaca917b1aa12dfc78c34727fffb5b09bdf766b1b
parent8c812dca4d68f3c11e6f6d28cd8e92b4282909a6 (diff)
netfilter: nf_conntrack: fix racy timer handling with reliable events
commit 5b423f6a40a0327f9d40bc8b97ce9be266f74368 upstream. Existing code assumes that del_timer returns true for alive conntrack entries. However, this is not true if reliable events are enabled. In that case, del_timer may return true for entries that were just inserted in the dying list. Note that packets / ctnetlink may hold references to conntrack entries that were just inserted to such list. This patch fixes the issue by adding an independent timer for event delivery. This increases the size of the ecache extension. Still we can revisit this later and use variable size extensions to allocate this area on demand. Tested-by: Oliver Smith <olipro@8.c.9.b.0.7.4.0.1.0.0.2.ip6.arpa> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--include/net/netfilter/nf_conntrack_ecache.h1
-rw-r--r--net/netfilter/nf_conntrack_core.c16
2 files changed, 12 insertions, 5 deletions
diff --git a/include/net/netfilter/nf_conntrack_ecache.h b/include/net/netfilter/nf_conntrack_ecache.h
index a88fb6939387..ea6f8a48ffe5 100644
--- a/include/net/netfilter/nf_conntrack_ecache.h
+++ b/include/net/netfilter/nf_conntrack_ecache.h
@@ -18,6 +18,7 @@ struct nf_conntrack_ecache {
u16 ctmask; /* bitmask of ct events to be delivered */
u16 expmask; /* bitmask of expect events to be delivered */
u32 pid; /* netlink pid of destroyer */
+ struct timer_list timeout;
};
static inline struct nf_conntrack_ecache *
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 1d15193a2513..7489bd301da5 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -247,12 +247,15 @@ static void death_by_event(unsigned long ul_conntrack)
{
struct nf_conn *ct = (void *)ul_conntrack;
struct net *net = nf_ct_net(ct);
+ struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct);
+
+ BUG_ON(ecache == NULL);
if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
/* bad luck, let's retry again */
- ct->timeout.expires = jiffies +
+ ecache->timeout.expires = jiffies +
(random32() % net->ct.sysctl_events_retry_timeout);
- add_timer(&ct->timeout);
+ add_timer(&ecache->timeout);
return;
}
/* we've got the event delivered, now it's dying */
@@ -266,6 +269,9 @@ static void death_by_event(unsigned long ul_conntrack)
void nf_ct_insert_dying_list(struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
+ struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct);
+
+ BUG_ON(ecache == NULL);
/* add this conntrack to the dying list */
spin_lock_bh(&nf_conntrack_lock);
@@ -273,10 +279,10 @@ void nf_ct_insert_dying_list(struct nf_conn *ct)
&net->ct.dying);
spin_unlock_bh(&nf_conntrack_lock);
/* set a new timer to retry event delivery */
- setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
- ct->timeout.expires = jiffies +
+ setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct);
+ ecache->timeout.expires = jiffies +
(random32() % net->ct.sysctl_events_retry_timeout);
- add_timer(&ct->timeout);
+ add_timer(&ecache->timeout);
}
EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);