[ovs-dev] [patch v2 4/6] conntrack: Tighten nat_clean.
Darrell Ball
dlu998 at gmail.com
Wed Sep 5 05:14:48 UTC 2018
nat_clean has a defunct optimization for calculating a hash outside the
scope of a bucket lock which potentially 'might' lead to referencing freed
memory. There is little point to this optimization, so just remove it.
Needs backporting to 2.8.
Signed-off-by: Darrell Ball <dlu998 at gmail.com>
---
lib/conntrack.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/lib/conntrack.c b/lib/conntrack.c
index 15e0a62..065c337 100644
--- a/lib/conntrack.c
+++ b/lib/conntrack.c
@@ -778,20 +778,22 @@ nat_clean(struct conntrack *ct, struct conn *conn,
{
ct_rwlock_wrlock(&ct->resources_lock);
nat_conn_keys_remove(&ct->nat_conn_keys, &conn->rev_key, ct->hash_basis);
- ct_rwlock_unlock(&ct->resources_lock);
- ct_lock_unlock(&ctb->lock);
unsigned bucket_rev_conn =
hash_to_bucket(conn_key_hash(&conn->rev_key, ct->hash_basis));
+ struct conn_key rev_key = conn->rev_key;
+ ct_rwlock_unlock(&ct->resources_lock);
+ ct_lock_unlock(&ctb->lock);
+
ct_lock_lock(&ct->buckets[bucket_rev_conn].lock);
ct_rwlock_wrlock(&ct->resources_lock);
long long now = time_msec();
- struct conn *rev_conn = conn_lookup(ct, &conn->rev_key, now);
+ struct conn *rev_conn = conn_lookup(ct, &rev_key, now);
struct nat_conn_key_node *nat_conn_key_node =
- nat_conn_keys_lookup(&ct->nat_conn_keys, &conn->rev_key,
+ nat_conn_keys_lookup(&ct->nat_conn_keys, &rev_key,
ct->hash_basis);
- /* In the unlikely event, rev conn was recreated, then skip
- * rev_conn cleanup. */
+ /* In the unlikely event, 'rev_conn' was recreated, then skip
+ * 'rev_conn' cleanup. */
if (rev_conn && (!nat_conn_key_node ||
conn_key_cmp(&nat_conn_key_node->value,
&rev_conn->rev_key))) {
--
1.9.1
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