Patrick McHardy
ec68e97ded
Fix {nf,ip}_ct_iterate_cleanup unconfirmed list handling:
- unconfirmed entries can not be killed manually, they are removed on
confirmation or final destruction of the conntrack entry, which means
we might iterate forever without making forward progress.
This can happen in combination with the conntrack event cache, which
holds a reference to the conntrack entry, which is only released when
the packet makes it all the way through the stack or a different
packet is handled.
- taking references to an unconfirmed entry and using it outside the
locked section doesn't work, the list entries are not refcounted and
another CPU might already be waiting to destroy the entry
What the code really wants to do is make sure the references of the hash
table to the selected conntrack entries are released, so they will be
destroyed once all references from skbs and the event cache are dropped.
Since unconfirmed entries haven't even entered the hash yet, simply mark
them as dying and skip confirmation based on that.
Reported and tested by Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
62 lines
1.8 KiB
C
62 lines
1.8 KiB
C
#ifndef _IP_CONNTRACK_CORE_H
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#define _IP_CONNTRACK_CORE_H
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#include <linux/netfilter.h>
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#define MAX_IP_CT_PROTO 256
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extern struct ip_conntrack_protocol *ip_ct_protos[MAX_IP_CT_PROTO];
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/* This header is used to share core functionality between the
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standalone connection tracking module, and the compatibility layer's use
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of connection tracking. */
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extern unsigned int ip_conntrack_in(unsigned int hooknum,
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struct sk_buff **pskb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *));
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extern int ip_conntrack_init(void);
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extern void ip_conntrack_cleanup(void);
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struct ip_conntrack_protocol;
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extern int
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ip_ct_get_tuple(const struct iphdr *iph,
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const struct sk_buff *skb,
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unsigned int dataoff,
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struct ip_conntrack_tuple *tuple,
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const struct ip_conntrack_protocol *protocol);
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extern int
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ip_ct_invert_tuple(struct ip_conntrack_tuple *inverse,
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const struct ip_conntrack_tuple *orig,
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const struct ip_conntrack_protocol *protocol);
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/* Find a connection corresponding to a tuple. */
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struct ip_conntrack_tuple_hash *
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ip_conntrack_find_get(const struct ip_conntrack_tuple *tuple,
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const struct ip_conntrack *ignored_conntrack);
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extern int __ip_conntrack_confirm(struct sk_buff **pskb);
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/* Confirm a connection: returns NF_DROP if packet must be dropped. */
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static inline int ip_conntrack_confirm(struct sk_buff **pskb)
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{
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struct ip_conntrack *ct = (struct ip_conntrack *)(*pskb)->nfct;
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int ret = NF_ACCEPT;
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if (ct) {
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if (!is_confirmed(ct) && !is_dying(ct))
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ret = __ip_conntrack_confirm(pskb);
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ip_ct_deliver_cached_events(ct);
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}
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return ret;
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}
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extern void ip_ct_unlink_expect(struct ip_conntrack_expect *exp);
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extern struct list_head *ip_conntrack_hash;
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extern struct list_head ip_conntrack_expect_list;
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extern rwlock_t ip_conntrack_lock;
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#endif /* _IP_CONNTRACK_CORE_H */
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