net: remove ifalias on empty given alias

This patch removes the potentially allocated ifalias when the (new) given alias is empty.

E.g. when setting

echo "" > /sys/class/net/eth0/ifalias

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index e91390533999..a90737fe2472 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -967,6 +967,14 @@ int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
         if (len >= IFALIASZ)
                 return -EINVAL;
 
+        if (!len) {
+                if (dev->ifalias) {
+                        kfree(dev->ifalias);
+                        dev->ifalias = NULL;
+                }
+                return 0;
+        }
+
         dev->ifalias = krealloc(dev->ifalias, len+1, GFP_KERNEL);
         if (!dev->ifalias)
                 return -ENOMEM;