From: Mingli Yu <Mingli.Yu@windriver.com>
Date: Thu, 20 Sep 2018 10:02:48 +0000 (+0200)
Subject: Linux gethostid: Check for NULL value from gethostbyname_r [BZ #23679]
X-Git-Tag: glibc-2.29~445
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1214ba06e6771acb953a190091b0f6055c64fd25;p=thirdparty%2Fglibc.git

Linux gethostid: Check for NULL value from gethostbyname_r [BZ #23679]

A NULL value can happen with certain gethostbyname_r failures.
---

diff --git a/ChangeLog b/ChangeLog
index d5becac41c7..4a66ea4c2a1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2018-09-20  Mingli Yu  <Mingli.Yu@windriver.com>
+
+	* sysdeps/unix/sysv/linux/gethostid.c (gethostid): Check for NULL
+	value from gethostbyname_r.
+
 2018-09-19  Carlos O'Donell  <carlos@redhat.com>
 
 	* stdlib/tst-setcontext9.c (f1): Rename to...
diff --git a/sysdeps/unix/sysv/linux/gethostid.c b/sysdeps/unix/sysv/linux/gethostid.c
index 2e20f034dc1..ee0190e7f94 100644
--- a/sysdeps/unix/sysv/linux/gethostid.c
+++ b/sysdeps/unix/sysv/linux/gethostid.c
@@ -102,12 +102,12 @@ gethostid (void)
     {
       int ret = __gethostbyname_r (hostname, &hostbuf,
 				   tmpbuf.data, tmpbuf.length, &hp, &herr);
-      if (ret == 0)
+      if (ret == 0 && hp != NULL)
 	break;
       else
 	{
 	  /* Enlarge the buffer on ERANGE.  */
-	  if (herr == NETDB_INTERNAL && errno == ERANGE)
+	  if (ret != 0 && herr == NETDB_INTERNAL && errno == ERANGE)
 	    {
 	      if (!scratch_buffer_grow (&tmpbuf))
 		return 0;