commit d527c860f5a3f0ed687bd03f0cb464612dc23408

Author: Florian Weimer <fweimer@redhat.com>

Date:   Tue Nov 27 16:12:43 2018 +0100

    CVE-2018-19591: if_nametoindex: Fix descriptor for overlong name [BZ #23927]

diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c

index e3d08982d9931108..782fc5e1750e9ead 100644

--- a/sysdeps/unix/sysv/linux/if_index.c

+++ b/sysdeps/unix/sysv/linux/if_index.c

@@ -38,11 +38,6 @@ __if_nametoindex (const char *ifname)

   return 0;

 #else

   struct ifreq ifr;

-  int fd = __opensock ();

-

-  if (fd < 0)

-    return 0;

-

   if (strlen (ifname) >= IFNAMSIZ)

     {

       __set_errno (ENODEV);

@@ -50,6 +45,12 @@ __if_nametoindex (const char *ifname)

     }

   strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));

+

+  int fd = __opensock ();

+

+  if (fd < 0)

+    return 0;

+

   if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0)

     {

       int saved_errno = errno;