diff options
Diffstat (limited to 'net/netfilter/nfnetlink.c')
| -rw-r--r-- | net/netfilter/nfnetlink.c | 88 |
1 files changed, 84 insertions, 4 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index 7e2c8dd01408..6d18fb346868 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -44,6 +44,10 @@ MODULE_DESCRIPTION("Netfilter messages via netlink socket"); static unsigned int nfnetlink_pernet_id __read_mostly; +#ifdef CONFIG_NF_CONNTRACK_EVENTS +static DEFINE_SPINLOCK(nfnl_grp_active_lock); +#endif + struct nfnl_net { struct sock *nfnl; }; @@ -290,6 +294,7 @@ replay: nfnl_lock(subsys_id); if (nfnl_dereference_protected(subsys_id) != ss || nfnetlink_find_client(type, ss) != nc) { + nfnl_unlock(subsys_id); err = -EAGAIN; break; } @@ -626,7 +631,7 @@ static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh) nfgenmsg = nlmsg_data(nlh); skb_pull(skb, msglen); /* Work around old nft using host byte order */ - if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES) + if (nfgenmsg->res_id == (__force __be16)NFNL_SUBSYS_NFTABLES) res_id = NFNL_SUBSYS_NFTABLES; else res_id = ntohs(nfgenmsg->res_id); @@ -654,7 +659,44 @@ static void nfnetlink_rcv(struct sk_buff *skb) netlink_rcv_skb(skb, nfnetlink_rcv_msg); } -#ifdef CONFIG_MODULES +static void nfnetlink_bind_event(struct net *net, unsigned int group) +{ +#ifdef CONFIG_NF_CONNTRACK_EVENTS + int type, group_bit; + u8 v; + + /* All NFNLGRP_CONNTRACK_* group bits fit into u8. + * The other groups are not relevant and can be ignored. + */ + if (group >= 8) + return; + + type = nfnl_group2type[group]; + + switch (type) { + case NFNL_SUBSYS_CTNETLINK: + break; + case NFNL_SUBSYS_CTNETLINK_EXP: + break; + default: + return; + } + + group_bit = (1 << group); + + spin_lock(&nfnl_grp_active_lock); + v = READ_ONCE(net->ct.ctnetlink_has_listener); + if ((v & group_bit) == 0) { + v |= group_bit; + + /* read concurrently without nfnl_grp_active_lock held. */ + WRITE_ONCE(net->ct.ctnetlink_has_listener, v); + } + + spin_unlock(&nfnl_grp_active_lock); +#endif +} + static int nfnetlink_bind(struct net *net, int group) { const struct nfnetlink_subsystem *ss; @@ -670,9 +712,48 @@ static int nfnetlink_bind(struct net *net, int group) rcu_read_unlock(); if (!ss) request_module_nowait("nfnetlink-subsys-%d", type); + + nfnetlink_bind_event(net, group); return 0; } + +static void nfnetlink_unbind(struct net *net, int group) +{ +#ifdef CONFIG_NF_CONNTRACK_EVENTS + int type, group_bit; + + if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) + return; + + type = nfnl_group2type[group]; + + switch (type) { + case NFNL_SUBSYS_CTNETLINK: + break; + case NFNL_SUBSYS_CTNETLINK_EXP: + break; + default: + return; + } + + /* ctnetlink_has_listener is u8 */ + if (group >= 8) + return; + + group_bit = (1 << group); + + spin_lock(&nfnl_grp_active_lock); + if (!nfnetlink_has_listeners(net, group)) { + u8 v = READ_ONCE(net->ct.ctnetlink_has_listener); + + v &= ~group_bit; + + /* read concurrently without nfnl_grp_active_lock held. */ + WRITE_ONCE(net->ct.ctnetlink_has_listener, v); + } + spin_unlock(&nfnl_grp_active_lock); #endif +} static int __net_init nfnetlink_net_init(struct net *net) { @@ -680,9 +761,8 @@ static int __net_init nfnetlink_net_init(struct net *net) struct netlink_kernel_cfg cfg = { .groups = NFNLGRP_MAX, .input = nfnetlink_rcv, -#ifdef CONFIG_MODULES .bind = nfnetlink_bind, -#endif + .unbind = nfnetlink_unbind, }; nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); |