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authorJozsef Kadlecsik <kadlec@blackhole.kfki.hu>2012-02-24 11:45:49 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2012-02-24 12:24:15 +0100
commit7d367e06688dc7a2cc98c2ace04e1296e1d987e2 (patch)
treebf4a9a6497dec37fdd4a31999cb218277e2ba656 /net
parent279072882dc0149e5740dace075e1a49f087046d (diff)
downloadlinux-linaro-stable-7d367e06688dc7a2cc98c2ace04e1296e1d987e2.tar.gz
netfilter: ctnetlink: fix soft lockup when netlink adds new entries (v2)
Marcell Zambo and Janos Farago noticed and reported that when new conntrack entries are added via netlink and the conntrack table gets full, soft lockup happens. This is because the nf_conntrack_lock is held while nf_conntrack_alloc is called, which is in turn wants to lock nf_conntrack_lock while evicting entries from the full table. The patch fixes the soft lockup with limiting the holding of the nf_conntrack_lock to the minimum, where it's absolutely required. It required to extend (and thus change) nf_conntrack_hash_insert so that it makes sure conntrack and ctnetlink do not add the same entry twice to the conntrack table. Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_conntrack_core.c38
-rw-r--r--net/netfilter/nf_conntrack_netlink.c46
2 files changed, 50 insertions, 34 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 76613f5a55c0..ed86a3be678e 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -404,19 +404,49 @@ static void __nf_conntrack_hash_insert(struct nf_conn *ct,
&net->ct.hash[repl_hash]);
}
-void nf_conntrack_hash_insert(struct nf_conn *ct)
+int
+nf_conntrack_hash_check_insert(struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
unsigned int hash, repl_hash;
+ struct nf_conntrack_tuple_hash *h;
+ struct hlist_nulls_node *n;
u16 zone;
zone = nf_ct_zone(ct);
- hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
- repl_hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+ hash = hash_conntrack(net, zone,
+ &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+ repl_hash = hash_conntrack(net, zone,
+ &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+
+ spin_lock_bh(&nf_conntrack_lock);
+ /* See if there's one in the list already, including reverse */
+ hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
+ if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
+ &h->tuple) &&
+ zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
+ goto out;
+ hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
+ if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
+ &h->tuple) &&
+ zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
+ goto out;
+
+ add_timer(&ct->timeout);
+ nf_conntrack_get(&ct->ct_general);
__nf_conntrack_hash_insert(ct, hash, repl_hash);
+ NF_CT_STAT_INC(net, insert);
+ spin_unlock_bh(&nf_conntrack_lock);
+
+ return 0;
+
+out:
+ NF_CT_STAT_INC(net, insert_failed);
+ spin_unlock_bh(&nf_conntrack_lock);
+ return -EEXIST;
}
-EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
+EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
/* Confirm a connection given skb; places it in hash table */
int
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 9307b033c0c9..30c9d4ca0218 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1367,15 +1367,12 @@ ctnetlink_create_conntrack(struct net *net, u16 zone,
nf_ct_protonum(ct));
if (helper == NULL) {
rcu_read_unlock();
- spin_unlock_bh(&nf_conntrack_lock);
#ifdef CONFIG_MODULES
if (request_module("nfct-helper-%s", helpname) < 0) {
- spin_lock_bh(&nf_conntrack_lock);
err = -EOPNOTSUPP;
goto err1;
}
- spin_lock_bh(&nf_conntrack_lock);
rcu_read_lock();
helper = __nf_conntrack_helper_find(helpname,
nf_ct_l3num(ct),
@@ -1468,8 +1465,10 @@ ctnetlink_create_conntrack(struct net *net, u16 zone,
if (tstamp)
tstamp->start = ktime_to_ns(ktime_get_real());
- add_timer(&ct->timeout);
- nf_conntrack_hash_insert(ct);
+ err = nf_conntrack_hash_check_insert(ct);
+ if (err < 0)
+ goto err2;
+
rcu_read_unlock();
return ct;
@@ -1490,6 +1489,7 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
struct nf_conntrack_tuple otuple, rtuple;
struct nf_conntrack_tuple_hash *h = NULL;
struct nfgenmsg *nfmsg = nlmsg_data(nlh);
+ struct nf_conn *ct;
u_int8_t u3 = nfmsg->nfgen_family;
u16 zone;
int err;
@@ -1510,27 +1510,22 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
return err;
}
- spin_lock_bh(&nf_conntrack_lock);
if (cda[CTA_TUPLE_ORIG])
- h = __nf_conntrack_find(net, zone, &otuple);
+ h = nf_conntrack_find_get(net, zone, &otuple);
else if (cda[CTA_TUPLE_REPLY])
- h = __nf_conntrack_find(net, zone, &rtuple);
+ h = nf_conntrack_find_get(net, zone, &rtuple);
if (h == NULL) {
err = -ENOENT;
if (nlh->nlmsg_flags & NLM_F_CREATE) {
- struct nf_conn *ct;
enum ip_conntrack_events events;
ct = ctnetlink_create_conntrack(net, zone, cda, &otuple,
&rtuple, u3);
- if (IS_ERR(ct)) {
- err = PTR_ERR(ct);
- goto out_unlock;
- }
+ if (IS_ERR(ct))
+ return PTR_ERR(ct);
+
err = 0;
- nf_conntrack_get(&ct->ct_general);
- spin_unlock_bh(&nf_conntrack_lock);
if (test_bit(IPS_EXPECTED_BIT, &ct->status))
events = IPCT_RELATED;
else
@@ -1545,23 +1540,19 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
ct, NETLINK_CB(skb).pid,
nlmsg_report(nlh));
nf_ct_put(ct);
- } else
- spin_unlock_bh(&nf_conntrack_lock);
+ }
return err;
}
/* implicit 'else' */
- /* We manipulate the conntrack inside the global conntrack table lock,
- * so there's no need to increase the refcount */
err = -EEXIST;
+ ct = nf_ct_tuplehash_to_ctrack(h);
if (!(nlh->nlmsg_flags & NLM_F_EXCL)) {
- struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
-
+ spin_lock_bh(&nf_conntrack_lock);
err = ctnetlink_change_conntrack(ct, cda);
+ spin_unlock_bh(&nf_conntrack_lock);
if (err == 0) {
- nf_conntrack_get(&ct->ct_general);
- spin_unlock_bh(&nf_conntrack_lock);
nf_conntrack_eventmask_report((1 << IPCT_REPLY) |
(1 << IPCT_ASSURED) |
(1 << IPCT_HELPER) |
@@ -1570,15 +1561,10 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
(1 << IPCT_MARK),
ct, NETLINK_CB(skb).pid,
nlmsg_report(nlh));
- nf_ct_put(ct);
- } else
- spin_unlock_bh(&nf_conntrack_lock);
-
- return err;
+ }
}
-out_unlock:
- spin_unlock_bh(&nf_conntrack_lock);
+ nf_ct_put(ct);
return err;
}