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authorXin Long <lucien.xin@gmail.com>2016-12-20 19:14:34 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2016-12-23 15:20:01 +0100
commit6c5d5cfbe3c59429e6d6f66477a7609aacf69751 (patch)
tree19435ae7ae7d2fe3d802de8672a535597eca32ab /net
parent053d20f5712529016eae10356e0dea9b360325bd (diff)
downloadlinux-6c5d5cfbe3c59429e6d6f66477a7609aacf69751.tar.bz2
netfilter: ipt_CLUSTERIP: check duplicate config when initializing
Now when adding an ipt_CLUSTERIP rule, it only checks duplicate config in clusterip_config_find_get(). But after that, there may be still another thread to insert a config with the same ip, then it leaves proc_create_data to do duplicate check. It's more reasonable to check duplicate config by ipt_CLUSTERIP itself, instead of checking it by proc fs duplicate file check. Before, when proc fs allowed duplicate name files in a directory, It could even crash kernel because of use-after-free. This patch is to check duplicate config under the protection of clusterip net lock when initializing a new config and correct the return err. Note that it also moves proc file node creation after adding new config, as proc_create_data may sleep, it couldn't be called under the clusterip_net lock. clusterip_config_find_get returns NULL if c->pde is null to make sure it can't be used until the proc file node creation is done. Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/netfilter/ipt_CLUSTERIP.c34
1 files changed, 23 insertions, 11 deletions
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 21db00d0362b..a6b8c1a4102b 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -144,7 +144,7 @@ clusterip_config_find_get(struct net *net, __be32 clusterip, int entry)
rcu_read_lock_bh();
c = __clusterip_config_find(net, clusterip);
if (c) {
- if (unlikely(!atomic_inc_not_zero(&c->refcount)))
+ if (!c->pde || unlikely(!atomic_inc_not_zero(&c->refcount)))
c = NULL;
else if (entry)
atomic_inc(&c->entries);
@@ -166,14 +166,15 @@ clusterip_config_init_nodelist(struct clusterip_config *c,
static struct clusterip_config *
clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
- struct net_device *dev)
+ struct net_device *dev)
{
+ struct net *net = dev_net(dev);
struct clusterip_config *c;
- struct clusterip_net *cn = net_generic(dev_net(dev), clusterip_net_id);
+ struct clusterip_net *cn = net_generic(net, clusterip_net_id);
c = kzalloc(sizeof(*c), GFP_ATOMIC);
if (!c)
- return NULL;
+ return ERR_PTR(-ENOMEM);
c->dev = dev;
c->clusterip = ip;
@@ -185,6 +186,17 @@ clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
atomic_set(&c->refcount, 1);
atomic_set(&c->entries, 1);
+ spin_lock_bh(&cn->lock);
+ if (__clusterip_config_find(net, ip)) {
+ spin_unlock_bh(&cn->lock);
+ kfree(c);
+
+ return ERR_PTR(-EBUSY);
+ }
+
+ list_add_rcu(&c->list, &cn->configs);
+ spin_unlock_bh(&cn->lock);
+
#ifdef CONFIG_PROC_FS
{
char buffer[16];
@@ -195,16 +207,16 @@ clusterip_config_init(const struct ipt_clusterip_tgt_info *i, __be32 ip,
cn->procdir,
&clusterip_proc_fops, c);
if (!c->pde) {
+ spin_lock_bh(&cn->lock);
+ list_del_rcu(&c->list);
+ spin_unlock_bh(&cn->lock);
kfree(c);
- return NULL;
+
+ return ERR_PTR(-ENOMEM);
}
}
#endif
- spin_lock_bh(&cn->lock);
- list_add_rcu(&c->list, &cn->configs);
- spin_unlock_bh(&cn->lock);
-
return c;
}
@@ -410,9 +422,9 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
config = clusterip_config_init(cipinfo,
e->ip.dst.s_addr, dev);
- if (!config) {
+ if (IS_ERR(config)) {
dev_put(dev);
- return -ENOMEM;
+ return PTR_ERR(config);
}
dev_mc_add(config->dev, config->clustermac);
}