From 9e2f6c5d78db6647eb9d7bfeb20b9e0f9ff2c56c Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Thu, 29 Mar 2018 17:03:35 +0300 Subject: [PATCH] netfilter: Rework xt_TEE netdevice notifier Register netdevice notifier for every iptable entry is not good, since this breaks modularity, and the hidden synchronization is based on rtnl_lock(). This patch reworks the synchronization via new lock, while the rest of logic remains as it was before. This is required for the next patch. Tested via: while :; do unshare -n iptables -t mangle -A OUTPUT -j TEE --gateway 1.1.1.2 --oif lo; done Signed-off-by: Kirill Tkhai Acked-by: Pablo Neira Ayuso Signed-off-by: David S. Miller --- net/netfilter/xt_TEE.c | 73 ++++++++++++++++++++++++++---------------- 1 file changed, 46 insertions(+), 27 deletions(-) diff --git a/net/netfilter/xt_TEE.c b/net/netfilter/xt_TEE.c index 86b0580b2216..475957cfcf50 100644 --- a/net/netfilter/xt_TEE.c +++ b/net/netfilter/xt_TEE.c @@ -20,7 +20,7 @@ #include struct xt_tee_priv { - struct notifier_block notifier; + struct list_head list; struct xt_tee_tginfo *tginfo; int oif; }; @@ -51,29 +51,35 @@ tee_tg6(struct sk_buff *skb, const struct xt_action_param *par) } #endif +static DEFINE_MUTEX(priv_list_mutex); +static LIST_HEAD(priv_list); + static int tee_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) { struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct xt_tee_priv *priv; - priv = container_of(this, struct xt_tee_priv, notifier); - switch (event) { - case NETDEV_REGISTER: - if (!strcmp(dev->name, priv->tginfo->oif)) - priv->oif = dev->ifindex; - break; - case NETDEV_UNREGISTER: - if (dev->ifindex == priv->oif) - priv->oif = -1; - break; - case NETDEV_CHANGENAME: - if (!strcmp(dev->name, priv->tginfo->oif)) - priv->oif = dev->ifindex; - else if (dev->ifindex == priv->oif) - priv->oif = -1; - break; + mutex_lock(&priv_list_mutex); + list_for_each_entry(priv, &priv_list, list) { + switch (event) { + case NETDEV_REGISTER: + if (!strcmp(dev->name, priv->tginfo->oif)) + priv->oif = dev->ifindex; + break; + case NETDEV_UNREGISTER: + if (dev->ifindex == priv->oif) + priv->oif = -1; + break; + case NETDEV_CHANGENAME: + if (!strcmp(dev->name, priv->tginfo->oif)) + priv->oif = dev->ifindex; + else if (dev->ifindex == priv->oif) + priv->oif = -1; + break; + } } + mutex_unlock(&priv_list_mutex); return NOTIFY_DONE; } @@ -89,8 +95,6 @@ static int tee_tg_check(const struct xt_tgchk_param *par) return -EINVAL; if (info->oif[0]) { - int ret; - if (info->oif[sizeof(info->oif)-1] != '\0') return -EINVAL; @@ -100,14 +104,11 @@ static int tee_tg_check(const struct xt_tgchk_param *par) priv->tginfo = info; priv->oif = -1; - priv->notifier.notifier_call = tee_netdev_event; info->priv = priv; - ret = register_netdevice_notifier(&priv->notifier); - if (ret) { - kfree(priv); - return ret; - } + mutex_lock(&priv_list_mutex); + list_add(&priv->list, &priv_list); + mutex_unlock(&priv_list_mutex); } else info->priv = NULL; @@ -120,7 +121,9 @@ static void tee_tg_destroy(const struct xt_tgdtor_param *par) struct xt_tee_tginfo *info = par->targinfo; if (info->priv) { - unregister_netdevice_notifier(&info->priv->notifier); + mutex_lock(&priv_list_mutex); + list_del(&info->priv->list); + mutex_unlock(&priv_list_mutex); kfree(info->priv); } static_key_slow_dec(&xt_tee_enabled); @@ -153,13 +156,29 @@ static struct xt_target tee_tg_reg[] __read_mostly = { #endif }; +static struct notifier_block tee_netdev_notifier = { + .notifier_call = tee_netdev_event, +}; + static int __init tee_tg_init(void) { - return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); + int ret; + + ret = xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); + if (ret) + return ret; + ret = register_netdevice_notifier(&tee_netdev_notifier); + if (ret) { + xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); + return ret; + } + + return 0; } static void __exit tee_tg_exit(void) { + unregister_netdevice_notifier(&tee_netdev_notifier); xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); } -- 2.30.2