{
struct nss_database_data data;
__libc_lock_define (, lock);
+ /* If "/" changes, we switched into a container and do NOT want to
+ reload anything. This data must be persistent across
+ reloads. */
+ ino64_t root_ino;
+ dev_t root_dev;
};
result->data.initialized = true;
result->data.reload_disabled = false;
__libc_lock_init (result->lock);
+ result->root_ino = 0;
+ result->root_dev = 0;
}
return result;
}
nss_action_list *result,
enum nss_database database_index)
{
+ struct stat64 str;
+
/* Acquire MO is needed because the thread that sets reload_disabled
may have loaded the configuration first, so synchronize with the
Release MO store there. */
__libc_lock_unlock (local->lock);
return true;
}
+
+ /* Before we reload, verify that "/" hasn't changed. We assume that
+ errors here are very unlikely, but the chance that we're entering
+ a container is also very unlikely, so we err on the side of both
+ very unlikely things not happening at the same time. */
+ if (__stat64 ("/", &str) != 0
+ || (local->root_ino != 0
+ && (str.st_ino != local->root_ino
+ || str.st_dev != local->root_dev)))
+ {
+ /* Change detected; disable reloading. */
+ atomic_store_release (&local->data.reload_disabled, 1);
+ __libc_lock_unlock (local->lock);
+ __nss_module_disable_loading ();
+ return true;
+ }
+ local->root_ino = str.st_ino;
+ local->root_dev = str.st_dev;
__libc_lock_unlock (local->lock);
/* Avoid overwriting the global configuration until we have loaded
--- /dev/null
+/* Test that reloading is disabled after a chroot.
+ Copyright (C) 2020-2021 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
+ <https://www.gnu.org/licenses/>. */
+
+#include <nss.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <pwd.h>
+#include <grp.h>
+#include <unistd.h>
+
+#include <support/support.h>
+#include <support/check.h>
+#include <support/xunistd.h>
+
+#include "nss_test.h"
+
+static struct passwd pwd_table1[] =
+ {
+ PWD_N (1234, "test1"),
+ PWD_N (4321, "test2"),
+ PWD_LAST ()
+ };
+
+static const char *group_4[] = {
+ "alpha", "beta", "gamma", "fred", NULL
+};
+
+static struct group group_table_data[] =
+ {
+ GRP (4),
+ GRP_LAST ()
+ };
+
+void
+_nss_test1_init_hook (test_tables *t)
+{
+ t->pwd_table = pwd_table1;
+ t->grp_table = group_table_data;
+}
+
+static struct passwd pwd_table2[] =
+ {
+ PWD_N (5, "test1"),
+ PWD_N (2468, "test2"),
+ PWD_LAST ()
+ };
+
+void
+_nss_test2_init_hook (test_tables *t)
+{
+ t->pwd_table = pwd_table2;
+}
+
+static int
+do_test (void)
+{
+ struct passwd *pw;
+ struct group *gr;
+ char buf1[PATH_MAX];
+ char buf2[PATH_MAX];
+
+ sprintf (buf1, "/subdir%s", support_slibdir_prefix);
+ xmkdirp (buf1, 0777);
+
+ /* Copy this DSO into the chroot so it *could* be loaded. */
+ sprintf (buf1, "%s/libnss_files.so.2", support_slibdir_prefix);
+ sprintf (buf2, "/subdir%s/libnss_files.so.2", support_slibdir_prefix);
+ support_copy_file (buf1, buf2);
+
+ /* Check we're using the "outer" nsswitch.conf. */
+
+ /* This uses the test1 DSO. */
+ pw = getpwnam ("test1");
+ TEST_VERIFY (pw != NULL);
+ if (pw)
+ TEST_COMPARE (pw->pw_uid, 1234);
+
+ /* This just loads the test2 DSO. */
+ gr = getgrnam ("name4");
+
+ /* Change the root dir. */
+
+ TEST_VERIFY (chroot ("/subdir") == 0);
+ chdir ("/");
+
+ /* Check we're NOT using the "inner" nsswitch.conf. */
+
+ /* Both DSOs are loaded, which is used? */
+ pw = getpwnam ("test2");
+ TEST_VERIFY (pw != NULL);
+ if (pw)
+ TEST_VERIFY (pw->pw_uid != 2468);
+
+ /* The "files" DSO should not be loaded. */
+ gr = getgrnam ("test3");
+ TEST_VERIFY (gr == NULL);
+
+ /* We should still be using the old configuration. */
+ pw = getpwnam ("test1");
+ TEST_VERIFY (pw != NULL);
+ if (pw)
+ TEST_COMPARE (pw->pw_uid, 1234);
+
+ return 0;
+}
+
+#include <support/test-driver.c>