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

[ Upstream commit 7364e445f62825758fa61195d237a5b8ecdd06ec ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/net/core/dev.c b/net/core/dev.c
index 46e2a29b5df3cc062fa8b05c835efc061a0e9786..f4a6e1439963886421e39db4d62e16848249e171 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -967,6 +967,8 @@ rollback:
  */
 int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
 {
+       char *new_ifalias;
+
        ASSERT_RTNL();
 
        if (len >= IFALIASZ)
@@ -980,9 +982,10 @@ 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;