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ae2d708ed8
The object and module refcounts are updated for each conntrack template, however, if we delete the iptables rules and we flush the timeout database, we may end up with invalid references to timeout object that are just gone. Resolve this problem by setting the timeout reference to NULL when the custom timeout entry is removed from our base. This patch requires some RCU trickery to ensure safe pointer handling. This handling is similar to what we already do with conntrack helpers, the idea is to avoid bumping the timeout object reference counter from the packet path to avoid the cost of atomic ops. Reported-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
111 lines
2.4 KiB
C
111 lines
2.4 KiB
C
#ifndef _NF_CONNTRACK_TIMEOUT_H
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#define _NF_CONNTRACK_TIMEOUT_H
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#include <net/net_namespace.h>
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#include <linux/netfilter/nf_conntrack_common.h>
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#include <linux/netfilter/nf_conntrack_tuple_common.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_extend.h>
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#define CTNL_TIMEOUT_NAME_MAX 32
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struct ctnl_timeout {
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struct list_head head;
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struct rcu_head rcu_head;
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atomic_t refcnt;
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char name[CTNL_TIMEOUT_NAME_MAX];
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__u16 l3num;
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struct nf_conntrack_l4proto *l4proto;
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char data[0];
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};
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struct nf_conn_timeout {
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struct ctnl_timeout __rcu *timeout;
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};
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static inline unsigned int *
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nf_ct_timeout_data(struct nf_conn_timeout *t)
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{
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struct ctnl_timeout *timeout;
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timeout = rcu_dereference(t->timeout);
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if (timeout == NULL)
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return NULL;
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return (unsigned int *)timeout->data;
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}
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static inline
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struct nf_conn_timeout *nf_ct_timeout_find(const struct nf_conn *ct)
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{
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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return nf_ct_ext_find(ct, NF_CT_EXT_TIMEOUT);
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#else
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return NULL;
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#endif
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}
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static inline
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struct nf_conn_timeout *nf_ct_timeout_ext_add(struct nf_conn *ct,
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struct ctnl_timeout *timeout,
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gfp_t gfp)
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{
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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struct nf_conn_timeout *timeout_ext;
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timeout_ext = nf_ct_ext_add(ct, NF_CT_EXT_TIMEOUT, gfp);
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if (timeout_ext == NULL)
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return NULL;
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rcu_assign_pointer(timeout_ext->timeout, timeout);
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return timeout_ext;
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#else
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return NULL;
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#endif
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};
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static inline unsigned int *
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nf_ct_timeout_lookup(struct net *net, struct nf_conn *ct,
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struct nf_conntrack_l4proto *l4proto)
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{
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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struct nf_conn_timeout *timeout_ext;
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unsigned int *timeouts;
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timeout_ext = nf_ct_timeout_find(ct);
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if (timeout_ext) {
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timeouts = nf_ct_timeout_data(timeout_ext);
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if (unlikely(!timeouts))
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timeouts = l4proto->get_timeouts(net);
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} else {
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timeouts = l4proto->get_timeouts(net);
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}
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return timeouts;
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#else
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return l4proto->get_timeouts(net);
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#endif
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}
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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int nf_conntrack_timeout_init(void);
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void nf_conntrack_timeout_fini(void);
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#else
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static inline int nf_conntrack_timeout_init(void)
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{
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return 0;
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}
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static inline void nf_conntrack_timeout_fini(void)
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{
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return;
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}
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#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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extern struct ctnl_timeout *(*nf_ct_timeout_find_get_hook)(const char *name);
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extern void (*nf_ct_timeout_put_hook)(struct ctnl_timeout *timeout);
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#endif
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#endif /* _NF_CONNTRACK_TIMEOUT_H */
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