[NETNS]: Double free in netlink_release.
Netlink protocol table is global for all namespaces. Some netlink
protocols have been virtualized, i.e. they have per/namespace netlink
socket. This difference can easily lead to double free if more than 1
namespace is started. Count the number of kernel netlink sockets to
track that this table is not used any more.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Tested-by: Alexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 21f9e30..29fef55 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -498,9 +498,12 @@
netlink_table_grab();
if (netlink_is_kernel(sk)) {
- kfree(nl_table[sk->sk_protocol].listeners);
- nl_table[sk->sk_protocol].module = NULL;
- nl_table[sk->sk_protocol].registered = 0;
+ BUG_ON(nl_table[sk->sk_protocol].registered == 0);
+ if (--nl_table[sk->sk_protocol].registered == 0) {
+ kfree(nl_table[sk->sk_protocol].listeners);
+ nl_table[sk->sk_protocol].module = NULL;
+ nl_table[sk->sk_protocol].registered = 0;
+ }
} else if (nlk->subscriptions)
netlink_update_listeners(sk);
netlink_table_ungrab();
@@ -1389,6 +1392,7 @@
nl_table[unit].registered = 1;
} else {
kfree(listeners);
+ nl_table[unit].registered++;
}
netlink_table_ungrab();