net/core: Fix potential memory leak in dev_set_alias()

Do not leak memory by updating pointer with potentially NULL realloc return value.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index f91abf800161..a39354ee1432 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1055,6 +1055,8 @@ rollback:
  */
 int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
 {
+        char *new_ifalias;
+
         ASSERT_RTNL();
 
         if (len >= IFALIASZ)
@@ -1068,9 +1070,10 @@ int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
                 return 0;
         }
 
-        dev->ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL);
-        if (!dev->ifalias)
+        new_ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL);
+        if (!new_ifalias)
                 return -ENOMEM;
+        dev->ifalias = new_ifalias;
 
         strlcpy(dev->ifalias, alias, len+1);
         return len;