[PATCH 1/3] dev: Prevent creating network devices with negative ifindex

[Serhey Popovych]

Interface index is signed integer, we can pass ifm->ifi_index
from userspace via netlink and create network device with
negative ifindex value.

Fixes: 9c7dafbfab15 ("net: Allow to create links with given ifindex")
Signed-off-by: Serhey Popovych <serhe.popov...@gmail.com>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 8658074..dae8010 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7491,7 +7491,7 @@ int register_netdevice(struct net_device *dev)
        }
 
        ret = -EBUSY;
-       if (!dev->ifindex)
+       if (dev->ifindex <= 0)
                dev->ifindex = dev_new_index(net);
        else if (__dev_get_by_index(net, dev->ifindex))
                goto err_uninit;
-- 
1.8.3.1