_nl_find_locale: Improve handling of crafted locale names [BZ #17137]

Prevent directory traversal in locale-related environment variables
(CVE-2014-0475).

3 files changed, 210 insertions, 1 deletions

diff --git a/localedata/ChangeLog b/localedata/ChangeLog
index 248b009..3c9a37c 100644
--- a/localedata/ChangeLog
+++ b/localedata/ChangeLog
@@ -1,3 +1,9 @@
+2014-07-02  Florian Weimer  <fweimer@redhat.com>
+
+	* tst-setlocale3.c: New file.
+	* Makefile (tests): Add tst-setlocale3.
+	(tst-setlocale3-ENV): New variable.
+
 2012-06-20  Petr Baudis  <pasky@ucw.cz>
 
 	* locales/mag_IN: Fix comment character.
diff --git a/localedata/Makefile b/localedata/Makefile
index 0873a55..214671e 100644
--- a/localedata/Makefile
+++ b/localedata/Makefile
@@ -78,7 +78,7 @@ locale_test_suite := tst_iswalnum tst_iswalpha tst_iswcntrl            \
 
 tests = $(locale_test_suite) tst-digits tst-setlocale bug-iconv-trans \
 	tst-leaks tst-mbswcs6 tst-xlocale1 tst-xlocale2 bug-usesetlocale \
-	tst-strfmon1 tst-sscanf bug-setlocale1 tst-setlocale2
+	tst-strfmon1 tst-sscanf bug-setlocale1 tst-setlocale2 tst-setlocale3
 ifeq (yes,$(build-shared))
 ifneq (no,$(PERL))
 tests: $(objpfx)mtrace-tst-leaks
diff --git a/localedata/tst-setlocale3.c b/localedata/tst-setlocale3.c
new file mode 100644
index 0000000..e3b21a9
--- /dev/null
+++ b/localedata/tst-setlocale3.c
@@ -0,0 +1,203 @@
+/* Regression test for setlocale invalid environment variable handling.
+   Copyright (C) 2014 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 <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* The result of setlocale may be overwritten by subsequent calls, so
+   this wrapper makes a copy.  */
+static char *
+setlocale_copy (int category, const char *locale)
+{
+  const char *result = setlocale (category, locale);
+  if (result == NULL)
+    return NULL;
+  return strdup (result);
+}
+
+static char *de_locale;
+
+static void
+setlocale_fail (const char *envstring)
+{
+  setenv ("LC_CTYPE", envstring, 1);
+  if (setlocale (LC_CTYPE, "") != NULL)
+    {
+      printf ("unexpected setlocale success for \"%s\" locale\n", envstring);
+      exit (1);
+    }
+  const char *newloc = setlocale (LC_CTYPE, NULL);
+  if (strcmp (newloc, de_locale) != 0)
+    {
+      printf ("failed setlocale call \"%s\" changed locale to \"%s\"\n",
+	      envstring, newloc);
+      exit (1);
+    }
+}
+
+static void
+setlocale_success (const char *envstring)
+{
+  setenv ("LC_CTYPE", envstring, 1);
+  char *newloc = setlocale_copy (LC_CTYPE, "");
+  if (newloc == NULL)
+    {
+      printf ("setlocale for \"%s\": %m\n", envstring);
+      exit (1);
+    }
+  if (strcmp (newloc, de_locale) == 0)
+    {
+      printf ("setlocale with LC_CTYPE=\"%s\" left locale at \"%s\"\n",
+	      envstring, de_locale);
+      exit (1);
+    }
+  if (setlocale (LC_CTYPE, de_locale) == NULL)
+    {
+      printf ("restoring locale \"%s\" with LC_CTYPE=\"%s\": %m\n",
+	      de_locale, envstring);
+      exit (1);
+    }
+  char *newloc2 = setlocale_copy (LC_CTYPE, newloc);
+  if (newloc2 == NULL)
+    {
+      printf ("restoring locale \"%s\" following \"%s\": %m\n",
+	      newloc, envstring);
+      exit (1);
+    }
+  if (strcmp (newloc, newloc2) != 0)
+    {
+      printf ("representation of locale \"%s\" changed from \"%s\" to \"%s\"",
+	      envstring, newloc, newloc2);
+      exit (1);
+    }
+  free (newloc);
+  free (newloc2);
+
+  if (setlocale (LC_CTYPE, de_locale) == NULL)
+    {
+      printf ("restoring locale \"%s\" with LC_CTYPE=\"%s\": %m\n",
+	      de_locale, envstring);
+      exit (1);
+    }
+}
+
+/* Checks that a known-good locale still works if LC_ALL contains a
+   value which should be ignored.  */
+static void
+setlocale_ignore (const char *to_ignore)
+{
+  const char *fr_locale = "fr_FR.UTF-8";
+  setenv ("LC_CTYPE", fr_locale, 1);
+  char *expected_locale = setlocale_copy (LC_CTYPE, "");
+  if (expected_locale == NULL)
+    {
+      printf ("setlocale with LC_CTYPE=\"%s\" failed: %m\n", fr_locale);
+      exit (1);
+    }
+  if (setlocale (LC_CTYPE, de_locale) == NULL)
+    {
+      printf ("failed to restore locale: %m\n");
+      exit (1);
+    }
+  unsetenv ("LC_CTYPE");
+
+  setenv ("LC_ALL", to_ignore, 1);
+  setenv ("LC_CTYPE", fr_locale, 1);
+  const char *actual_locale = setlocale (LC_CTYPE, "");
+  if (actual_locale == NULL)
+    {
+      printf ("setlocale with LC_ALL, LC_CTYPE=\"%s\" failed: %m\n",
+	      fr_locale);
+      exit (1);
+    }
+  if (strcmp (actual_locale, expected_locale) != 0)
+    {
+      printf ("setlocale under LC_ALL failed: got \"%s\", expected \"%s\"\n",
+	      actual_locale, expected_locale);
+      exit (1);
+    }
+  unsetenv ("LC_CTYPE");
+  setlocale_success (fr_locale);
+  unsetenv ("LC_ALL");
+  free (expected_locale);
+}
+
+static int
+do_test (void)
+{
+  /* The glibc test harness sets this environment variable
+     uncondionally.  */
+  unsetenv ("LC_ALL");
+
+  de_locale = setlocale_copy (LC_CTYPE, "de_DE.UTF-8");
+  if (de_locale == NULL)
+    {
+      printf ("setlocale (LC_CTYPE, \"de_DE.UTF-8\"): %m\n");
+      return 1;
+    }
+  setlocale_success ("C");
+  setlocale_success ("en_US.UTF-8");
+  setlocale_success ("/en_US.UTF-8");
+  setlocale_success ("//en_US.UTF-8");
+  setlocale_ignore ("");
+
+  setlocale_fail ("does-not-exist");
+  setlocale_fail ("/");
+  setlocale_fail ("/../localedata/en_US.UTF-8");
+  setlocale_fail ("en_US.UTF-8/");
+  setlocale_fail ("en_US.UTF-8/..");
+  setlocale_fail ("en_US.UTF-8/../en_US.UTF-8");
+  setlocale_fail ("../localedata/en_US.UTF-8");
+  {
+    size_t large_length = 1024;
+    char *large_name = malloc (large_length + 1);
+    if (large_name == NULL)
+      {
+	puts ("malloc failure");
+	return 1;
+      }
+    memset (large_name, '/', large_length);
+    const char *suffix = "en_US.UTF-8";
+    strcpy (large_name + large_length - strlen (suffix), suffix);
+    setlocale_fail (large_name);
+    free (large_name);
+  }
+  {
+    size_t huge_length = 64 * 1024 * 1024;
+    char *huge_name = malloc (huge_length + 1);
+    if (huge_name == NULL)
+      {
+	puts ("malloc failure");
+	return 1;
+      }
+    memset (huge_name, 'X', huge_length);
+    huge_name[huge_length] = '\0';
+    /* Construct a composite locale specification. */
+    const char *prefix = "LC_CTYPE=de_DE.UTF-8;LC_TIME=";
+    memcpy (huge_name, prefix, strlen (prefix));
+    setlocale_fail (huge_name);
+    free (huge_name);
+  }
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"