From 6d0b7b443c9735672bb76d003c3f7263c5292d7d Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Wed, 29 Apr 2015 14:41:25 +0200
Subject: [PATCH 23/27] CVE-2014-8121: Do not close NSS files database during
 iteration [BZ #18007]
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(cherry picked from commit e871e19b5f19d2e6595e911b0a5b1c19cda20cc7)

Fixes:
CVE-2014-8121 - Unexpected closing of nss_files databases after lookups
causes denial of service.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
---
 nss/Makefile              |   2 +-
 nss/nss_files/files-XXX.c |   2 +-
 nss/tst-nss-getpwent.c    | 118 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 120 insertions(+), 2 deletions(-)
 create mode 100644 nss/tst-nss-getpwent.c

diff --git a/nss/Makefile b/nss/Makefile
index d419baf..dc351dd 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -39,7 +39,7 @@ install-bin             := getent makedb
 makedb-modules = xmalloc hash-string
 extra-objs		+= $(makedb-modules:=.o)
 
-tests			= test-netdb tst-nss-test1 test-digits-dots
+tests			= test-netdb tst-nss-test1 test-digits-dots tst-nss-getpwent
 xtests			= bug-erange
 
 # Specify rules for the nss_* modules.  We have some services.
diff --git a/nss/nss_files/files-XXX.c b/nss/nss_files/files-XXX.c
index a7a45e5..a7ce5ea 100644
--- a/nss/nss_files/files-XXX.c
+++ b/nss/nss_files/files-XXX.c
@@ -134,7 +134,7 @@ CONCAT(_nss_files_set,ENTNAME) (int stayopen)
 
   __libc_lock_lock (lock);
 
-  status = internal_setent (stayopen);
+  status = internal_setent (1);
 
   if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0)
     {
diff --git a/nss/tst-nss-getpwent.c b/nss/tst-nss-getpwent.c
new file mode 100644
index 0000000..f2e8abc
--- /dev/null
+++ b/nss/tst-nss-getpwent.c
@@ -0,0 +1,118 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <pwd.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+do_test (void)
+{
+  /* Count the number of entries in the password database, and fetch
+     data from the first and last entries.  */
+  size_t count = 0;
+  struct passwd * pw;
+  char *first_name = NULL;
+  uid_t first_uid = 0;
+  char *last_name = NULL;
+  uid_t last_uid = 0;
+  setpwent ();
+  while ((pw  = getpwent ()) != NULL)
+    {
+      if (first_name == NULL)
+	{
+	  first_name = strdup (pw->pw_name);
+	  if (first_name == NULL)
+	    {
+	      printf ("strdup: %m\n");
+	      return 1;
+	    }
+	  first_uid = pw->pw_uid;
+	}
+
+      free (last_name);
+      last_name = strdup (pw->pw_name);
+      if (last_name == NULL)
+	{
+	  printf ("strdup: %m\n");
+	  return 1;
+	}
+      last_uid = pw->pw_uid;
+      ++count;
+    }
+  endpwent ();
+
+  if (count == 0)
+    {
+      printf ("No entries in the password database.\n");
+      return 0;
+    }
+
+  /* Try again, this time interleaving with name-based and UID-based
+     lookup operations.  The counts do not match if the interleaved
+     lookups affected the enumeration.  */
+  size_t new_count = 0;
+  setpwent ();
+  while ((pw  = getpwent ()) != NULL)
+    {
+      if (new_count == count)
+	{
+	  printf ("Additional entry in the password database.\n");
+	  return 1;
+	}
+      ++new_count;
+      struct passwd *pw2 = getpwnam (first_name);
+      if (pw2 == NULL)
+	{
+	  printf ("getpwnam (%s) failed: %m\n", first_name);
+	  return 1;
+	}
+      pw2 = getpwnam (last_name);
+      if (pw2 == NULL)
+	{
+	  printf ("getpwnam (%s) failed: %m\n", last_name);
+	  return 1;
+	}
+      pw2 = getpwuid (first_uid);
+      if (pw2 == NULL)
+	{
+	  printf ("getpwuid (%llu) failed: %m\n",
+		  (unsigned long long) first_uid);
+	  return 1;
+	}
+      pw2 = getpwuid (last_uid);
+      if (pw2 == NULL)
+	{
+	  printf ("getpwuid (%llu) failed: %m\n",
+		  (unsigned long long) last_uid);
+	  return 1;
+	}
+    }
+  endpwent ();
+  if (new_count < count)
+    {
+      printf ("Missing entry in the password database.\n");
+      return 1;
+    }
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
-- 
2.6.2