From ec68e97dedacc1c7fb20a4b23b7fa76bee56b5ff Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Sun, 4 Mar 2007 15:57:01 -0800 Subject: [PATCH] [NETFILTER]: conntrack: fix {nf,ip}_ct_iterate_cleanup endless loops 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 Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/linux/netfilter_ipv4/ip_conntrack_core.h | 2 +- include/net/netfilter/nf_conntrack_core.h | 2 +- net/ipv4/netfilter/ip_conntrack_core.c | 2 +- net/netfilter/nf_conntrack_core.c | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/netfilter_ipv4/ip_conntrack_core.h b/include/linux/netfilter_ipv4/ip_conntrack_core.h index 907d4f5ca5..e3a6df07aa 100644 --- a/include/linux/netfilter_ipv4/ip_conntrack_core.h +++ b/include/linux/netfilter_ipv4/ip_conntrack_core.h @@ -45,7 +45,7 @@ static inline int ip_conntrack_confirm(struct sk_buff **pskb) int ret = NF_ACCEPT; if (ct) { - if (!is_confirmed(ct)) + if (!is_confirmed(ct) && !is_dying(ct)) ret = __ip_conntrack_confirm(pskb); ip_ct_deliver_cached_events(ct); } diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h index 7fdc72c013..85634e1865 100644 --- a/include/net/netfilter/nf_conntrack_core.h +++ b/include/net/netfilter/nf_conntrack_core.h @@ -64,7 +64,7 @@ static inline int nf_conntrack_confirm(struct sk_buff **pskb) int ret = NF_ACCEPT; if (ct) { - if (!nf_ct_is_confirmed(ct)) + if (!nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct)) ret = __nf_conntrack_confirm(pskb); nf_ct_deliver_cached_events(ct); } diff --git a/net/ipv4/netfilter/ip_conntrack_core.c b/net/ipv4/netfilter/ip_conntrack_core.c index 07ba1dd136..23b99ae2cc 100644 --- a/net/ipv4/netfilter/ip_conntrack_core.c +++ b/net/ipv4/netfilter/ip_conntrack_core.c @@ -1254,7 +1254,7 @@ get_next_corpse(int (*iter)(struct ip_conntrack *i, void *data), list_for_each_entry(h, &unconfirmed, list) { ct = tuplehash_to_ctrack(h); if (iter(ct, data)) - goto found; + set_bit(IPS_DYING_BIT, &ct->status); } write_unlock_bh(&ip_conntrack_lock); return NULL; diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 32891ebc9e..4fdf4849ba 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1070,7 +1070,7 @@ get_next_corpse(int (*iter)(struct nf_conn *i, void *data), list_for_each_entry(h, &unconfirmed, list) { ct = nf_ct_tuplehash_to_ctrack(h); if (iter(ct, data)) - goto found; + set_bit(IPS_DYING_BIT, &ct->status); } write_unlock_bh(&nf_conntrack_lock); return NULL; -- 2.39.5