From 5b3501faa8741d50617ce4191c20061c6ef36cb3 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 8 Feb 2010 11:16:56 -0800 Subject: netfilter: nf_conntrack: per netns nf_conntrack_cachep nf_conntrack_cachep is currently shared by all netns instances, but because of SLAB_DESTROY_BY_RCU special semantics, this is wrong. If we use a shared slab cache, one object can instantly flight between one hash table (netns ONE) to another one (netns TWO), and concurrent reader (doing a lookup in netns ONE, 'finding' an object of netns TWO) can be fooled without notice, because no RCU grace period has to be observed between object freeing and its reuse. We dont have this problem with UDP/TCP slab caches because TCP/UDP hashtables are global to the machine (and each object has a pointer to its netns). If we use per netns conntrack hash tables, we also *must* use per netns conntrack slab caches, to guarantee an object can not escape from one namespace to another one. Signed-off-by: Eric Dumazet [Patrick: added unique slab name allocation] Cc: stable@kernel.org Signed-off-by: Patrick McHardy --- include/net/netns/conntrack.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/net') diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h index ba1ba0c5efd..aed23b6c847 100644 --- a/include/net/netns/conntrack.h +++ b/include/net/netns/conntrack.h @@ -11,6 +11,7 @@ struct nf_conntrack_ecache; struct netns_ct { atomic_t count; unsigned int expect_count; + struct kmem_cache *nf_conntrack_cachep; struct hlist_nulls_head *hash; struct hlist_head *expect_hash; struct hlist_nulls_head unconfirmed; @@ -28,5 +29,6 @@ struct netns_ct { #endif int hash_vmalloc; int expect_vmalloc; + char *slabname; }; #endif -- cgit v1.2.3 From d696c7bdaa55e2208e56c6f98e6bc1599f34286d Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 8 Feb 2010 11:18:07 -0800 Subject: netfilter: nf_conntrack: fix hash resizing with namespaces As noticed by Jon Masters , the conntrack hash size is global and not per namespace, but modifiable at runtime through /sys/module/nf_conntrack/hashsize. Changing the hash size will only resize the hash in the current namespace however, so other namespaces will use an invalid hash size. This can cause crashes when enlarging the hashsize, or false negative lookups when shrinking it. Move the hash size into the per-namespace data and only use the global hash size to initialize the per-namespace value when instanciating a new namespace. Additionally restrict hash resizing to init_net for now as other namespaces are not handled currently. Cc: stable@kernel.org Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/net/netns/conntrack.h | 1 + include/net/netns/ipv4.h | 1 + 2 files changed, 2 insertions(+) (limited to 'include/net') diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h index aed23b6c847..63d449807d9 100644 --- a/include/net/netns/conntrack.h +++ b/include/net/netns/conntrack.h @@ -11,6 +11,7 @@ struct nf_conntrack_ecache; struct netns_ct { atomic_t count; unsigned int expect_count; + unsigned int htable_size; struct kmem_cache *nf_conntrack_cachep; struct hlist_nulls_head *hash; struct hlist_head *expect_hash; diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index 2eb3814d625..9a4b8b71407 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -40,6 +40,7 @@ struct netns_ipv4 { struct xt_table *iptable_security; struct xt_table *nat_table; struct hlist_head *nat_bysource; + unsigned int nat_htable_size; int nat_vmalloced; #endif -- cgit v1.2.3