From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: [NETFILTER 01/10]: conntrack: fix {nf, ip}_ct_iterate_cleanup endless loops Date: Sun, 4 Mar 2007 21:19:59 +0100 (MET) Message-ID: <20070304201907.28582.32005.sendpatchset@localhost.localdomain> References: <20070304201906.28582.51903.sendpatchset@localhost.localdomain> Cc: netfilter-devel@lists.netfilter.org, Patrick McHardy To: davem@davemloft.net Return-path: In-Reply-To: <20070304201906.28582.51903.sendpatchset@localhost.localdomain> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-devel-bounces@lists.netfilter.org Errors-To: netfilter-devel-bounces@lists.netfilter.org List-Id: netfilter-devel.vger.kernel.org [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 --- commit 3b0f1308568d67be761a89c95354cce8617e6715 tree ab83a08e8daa26e2bb1051314e36da6a76cb0219 parent 2ff7354fe888f46f6629b57e463b0a1eb956c02b author Patrick McHardy Thu, 01 Mar 2007 15:15:49 +0100 committer Patrick McHardy Thu, 01 Mar 2007 15:15:49 +0100 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 907d4f5..e3a6df0 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(s 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 7fdc72c..85634e1 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(s 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 07ba1dd..23b99ae 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_co 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 32891eb..4fdf484 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_co 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;