[PATCH 5.16 087/164] udp_tunnel: Fix end of loop test in udp_tunnel_nic_unregister()

Greg Kroah-Hartman
2022-02-28T18:06:58Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit de7b2efacf4e83954aed3f029d347dfc0b7a4f49 upstream.

This test is checking if we exited the list via break or not. However
if it did not exit via a break then "node" does not point to a valid
udp_tunnel_nic_shared_node struct. It will work because of the way
the structs are laid out it's the equivalent of
"if (info->shared->udp_tunnel_nic_info != dev)" which will always be
true, but it's not the right way to test.

Fixes: 74cc6d182d03 ("udp_tunnel: add the ability to share port tables")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/udp_tunnel_nic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv4/udp_tunnel_nic.c
+++ b/net/ipv4/udp_tunnel_nic.c
@@ -846,7 +846,7 @@ udp_tunnel_nic_unregister(struct net_dev
list_for_each_entry(node, &info->shared->devices, list)
if (node->dev == dev)
break;
- if (node->dev != dev)
+ if (list_entry_is_head(node, &info->shared->devices, list))
return;

list_del(&node->list);