aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorEric Dumazet <eric.dumazet@gmail.com>2010-02-08 11:16:56 -0800
committerDavid S. Miller <davem@davemloft.net>2010-02-08 11:16:56 -0800
commit5b3501faa8741d50617ce4191c20061c6ef36cb3 (patch)
treefd3ac41baea9db5d795144da48cef46aca3e01f6
parent9edd7ca0a3e3999c260642c92fa008892d82ca6e (diff)
downloadlinux-linaro-stable-5b3501faa8741d50617ce4191c20061c6ef36cb3.tar.gz
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 <eric.dumazet@gmail.com> [Patrick: added unique slab name allocation] Cc: stable@kernel.org Signed-off-by: Patrick McHardy <kaber@trash.net>
-rw-r--r--include/net/netns/conntrack.h2
-rw-r--r--net/netfilter/nf_conntrack_core.c39
2 files changed, 25 insertions, 16 deletions
diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h
index ba1ba0c5efd1..aed23b6c8478 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
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 37e2b88313f2..9de4bd4c0dd7 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -63,8 +63,6 @@ EXPORT_SYMBOL_GPL(nf_conntrack_max);
struct nf_conn nf_conntrack_untracked __read_mostly;
EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
-static struct kmem_cache *nf_conntrack_cachep __read_mostly;
-
static int nf_conntrack_hash_rnd_initted;
static unsigned int nf_conntrack_hash_rnd;
@@ -572,7 +570,7 @@ struct nf_conn *nf_conntrack_alloc(struct net *net,
* Do not use kmem_cache_zalloc(), as this cache uses
* SLAB_DESTROY_BY_RCU.
*/
- ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
+ ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
if (ct == NULL) {
pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
atomic_dec(&net->ct.count);
@@ -611,7 +609,7 @@ void nf_conntrack_free(struct nf_conn *ct)
nf_ct_ext_destroy(ct);
atomic_dec(&net->ct.count);
nf_ct_ext_free(ct);
- kmem_cache_free(nf_conntrack_cachep, ct);
+ kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
}
EXPORT_SYMBOL_GPL(nf_conntrack_free);
@@ -1119,7 +1117,6 @@ static void nf_conntrack_cleanup_init_net(void)
nf_conntrack_helper_fini();
nf_conntrack_proto_fini();
- kmem_cache_destroy(nf_conntrack_cachep);
}
static void nf_conntrack_cleanup_net(struct net *net)
@@ -1137,6 +1134,8 @@ static void nf_conntrack_cleanup_net(struct net *net)
nf_conntrack_ecache_fini(net);
nf_conntrack_acct_fini(net);
nf_conntrack_expect_fini(net);
+ kmem_cache_destroy(net->ct.nf_conntrack_cachep);
+ kfree(net->ct.slabname);
free_percpu(net->ct.stat);
}
@@ -1272,15 +1271,6 @@ static int nf_conntrack_init_init_net(void)
NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
nf_conntrack_max);
- nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
- sizeof(struct nf_conn),
- 0, SLAB_DESTROY_BY_RCU, NULL);
- if (!nf_conntrack_cachep) {
- printk(KERN_ERR "Unable to create nf_conn slab cache\n");
- ret = -ENOMEM;
- goto err_cache;
- }
-
ret = nf_conntrack_proto_init();
if (ret < 0)
goto err_proto;
@@ -1302,8 +1292,6 @@ static int nf_conntrack_init_init_net(void)
err_helper:
nf_conntrack_proto_fini();
err_proto:
- kmem_cache_destroy(nf_conntrack_cachep);
-err_cache:
return ret;
}
@@ -1325,6 +1313,21 @@ static int nf_conntrack_init_net(struct net *net)
ret = -ENOMEM;
goto err_stat;
}
+
+ net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
+ if (!net->ct.slabname) {
+ ret = -ENOMEM;
+ goto err_slabname;
+ }
+
+ net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
+ sizeof(struct nf_conn), 0,
+ SLAB_DESTROY_BY_RCU, NULL);
+ if (!net->ct.nf_conntrack_cachep) {
+ printk(KERN_ERR "Unable to create nf_conn slab cache\n");
+ ret = -ENOMEM;
+ goto err_cache;
+ }
net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
&net->ct.hash_vmalloc, 1);
if (!net->ct.hash) {
@@ -1352,6 +1355,10 @@ err_expect:
nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
nf_conntrack_htable_size);
err_hash:
+ kmem_cache_destroy(net->ct.nf_conntrack_cachep);
+err_cache:
+ kfree(net->ct.slabname);
+err_slabname:
free_percpu(net->ct.stat);
err_stat:
return ret;