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

diff --git a/ChangeLog b/ChangeLog
index 9bf877e..086cbd4 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2018-11-27  Florian Weimer  <fweimer@redhat.com>
+
+       [BZ #23927]
+       CVE-2018-19591
+       * sysdeps/unix/sysv/linux/if_index.c (__if_nametoindex): Avoid
+       descriptor leak in case of ENODEV error.
+
 2018-11-27  Rafael Ávila de Espíndola  <rafael@espindo.la>
 
        [BZ #19767]

diff --git a/NEWS b/NEWS
index f488821..1098be1 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -57,7 +57,9 @@ Changes to build and runtime requirements:
 
 Security related changes:
 
-  [Add security related changes here]
+  CVE-2018-19591: A file descriptor leak in if_nametoindex can lead to a
+  denial of service due to resource exhaustion when processing getaddrinfo
+  calls with crafted host names.  Reported by Guido Vranken.
 
 The following bugs are resolved with this release:
 

diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c
index e3d0898..782fc5e 100644 (file)
--- 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;