6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jakub Kicinski <kuba@xxxxxxxxxx>
commit 1a83f4a7c156fa6bbd6b530e89fa3270bf3d9d1b upstream.
Altnames are accessed under RCU (dev_get_by_name_rcu())
but freed by kfree() with no synchronization point.
Each node has one or two allocations (node and a variable-size
name, sometimes the name is netdev->name). Adding rcu_heads
here is a bit tedious. Besides most code which unlists the names
already has rcu barriers - so take the simpler approach of adding
synchronize_rcu(). Note that the one on the unregistration path
(which matters more) is removed by the next fix.
Fixes: ff92741270bf ("net: introduce name_node struct to be used in hashlist")
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/dev.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -343,7 +343,6 @@ int netdev_name_node_alt_create(struct n
static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node)
{
list_del(&name_node->list);
- netdev_name_node_del(name_node);
kfree(name_node->name);
netdev_name_node_free(name_node);
}
@@ -362,6 +361,8 @@ int netdev_name_node_alt_destroy(struct
if (name_node == dev->name_node || name_node->dev != dev)
return -EINVAL;
+ netdev_name_node_del(name_node);
+ synchronize_rcu();
__netdev_name_node_alt_destroy(name_node);
return 0;
@@ -10838,6 +10839,7 @@ void unregister_netdevice_many_notify(st
synchronize_net();
list_for_each_entry(dev, head, unreg_list) {
+ struct netdev_name_node *name_node;
struct sk_buff *skb = NULL;
/* Shutdown queueing discipline. */
@@ -10865,6 +10867,9 @@ void unregister_netdevice_many_notify(st
dev_uc_flush(dev);
dev_mc_flush(dev);
+ netdev_for_each_altname(dev, name_node)
+ netdev_name_node_del(name_node);
+ synchronize_rcu();
netdev_name_node_alt_flush(dev);
netdev_name_node_free(dev->name_node);
