diff options
author | Xin Long <lucien.xin@gmail.com> | 2016-12-20 19:14:34 +0800 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-12-23 15:20:01 +0100 |
commit | 6c5d5cfbe3c59429e6d6f66477a7609aacf69751 (patch) | |
tree | 19435ae7ae7d2fe3d802de8672a535597eca32ab /net | |
parent | 053d20f5712529016eae10356e0dea9b360325bd (diff) | |
download | op-kernel-dev-6c5d5cfbe3c59429e6d6f66477a7609aacf69751.zip op-kernel-dev-6c5d5cfbe3c59429e6d6f66477a7609aacf69751.tar.gz |
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.c | 34 |
1 files changed, 23 insertions, 11 deletions
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 21db00d..a6b8c1a 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); } |