From: Florian Weimer <fweimer@redhat.com>
Date: Tue, 27 Nov 2018 15:12:43 +0000 (+0100)
Subject: CVE-2018-19591: if_nametoindex: Fix descriptor for overlong name [BZ #23927]
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ce6ba630dbc96f49eb1f30366aa62261df4792f9;p=thirdparty%2Fglibc.git

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

(cherry picked from commit d527c860f5a3f0ed687bd03f0cb464612dc23408)
---

diff --git a/ChangeLog b/ChangeLog
index 8c92ee77641..a9970036640 100644
--- 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.
+
 2018-11-19  Florian Weimer  <fweimer@redhat.com>
 
 	support: Print timestamps in timeout handler.
diff --git a/NEWS b/NEWS
index e5ca5903ec7..5290e21da9e 100644
--- a/NEWS
+++ b/NEWS
@@ -25,7 +25,13 @@ The following bugs are resolved with this release:
   [23717] Fix stack overflow in stdlib/tst-setcontext9
   [23821] si_band in siginfo_t has wrong type long int on sparc64
   [23822] ia64 static libm.a is missing exp2f, log2f and powf symbols
+  [23927] Linux if_nametoindex() does not close descriptor (CVE-2018-19591)
 
+Security related changes:
+
+  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.
 
 Version 2.28
 
diff --git a/sysdeps/unix/sysv/linux/if_index.c b/sysdeps/unix/sysv/linux/if_index.c
index e3d08982d99..782fc5e1750 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;