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@xxxxxxxxxx>
Tested-by: Alexey Dobriyan <adobriyan@xxxxxxxxxx>
---
net/netlink/af_netlink.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
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 @@ static int netlink_release(struct socket *sock)
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 @@ netlink_kernel_create(struct net *net, int unit, unsigned int groups,
nl_table[unit].registered = 1;
} else {
kfree(listeners);
+ nl_table[unit].registered++;
}
netlink_table_ungrab();
--
1.5.3.rc5
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