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-rw-r--r--nss/Makefile2
-rw-r--r--nss/nss_database.c27
-rw-r--r--nss/nss_module.c13
-rw-r--r--nss/nss_module.h3
-rw-r--r--nss/tst-reload2.c126
-rw-r--r--nss/tst-reload2.root/etc/nsswitch.conf2
-rw-r--r--nss/tst-reload2.root/subdir/etc/group1
-rw-r--r--nss/tst-reload2.root/subdir/etc/nsswitch.conf2
-rw-r--r--nss/tst-reload2.root/tst-reload2.script3
9 files changed, 178 insertions, 1 deletions
diff --git a/nss/Makefile b/nss/Makefile
index 5f6bf598a1..0906202db9 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -67,7 +67,7 @@ tests-container = \
tst-nss-files-hosts-long \
tst-nss-db-endpwent \
tst-nss-db-endgrent \
- tst-reload1
+ tst-reload1 tst-reload2
# Tests which need libdl
ifeq (yes,$(build-shared))
diff --git a/nss/nss_database.c b/nss/nss_database.c
index e719ec0865..cf0306adc4 100644
--- a/nss/nss_database.c
+++ b/nss/nss_database.c
@@ -33,6 +33,11 @@ struct nss_database_state
{
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;
};
@@ -54,6 +59,8 @@ global_state_allocate (void *closure)
result->data.initialized = true;
result->data.reload_disabled = false;
__libc_lock_init (result->lock);
+ result->root_ino = 0;
+ result->root_dev = 0;
}
return result;
}
@@ -356,6 +363,8 @@ nss_database_check_reload_and_get (struct nss_database_state *local,
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. */
@@ -379,6 +388,24 @@ nss_database_check_reload_and_get (struct nss_database_state *local,
__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
diff --git a/nss/nss_module.c b/nss/nss_module.c
index 1a9359930d..6c5f341f3e 100644
--- a/nss/nss_module.c
+++ b/nss/nss_module.c
@@ -349,6 +349,19 @@ __nss_disable_nscd (void (*cb) (size_t, struct traced_file *))
}
#endif
+/* Block attempts to dlopen any module we haven't already opened. */
+void
+__nss_module_disable_loading (void)
+{
+ __libc_lock_lock (nss_module_list_lock);
+
+ for (struct nss_module *p = nss_module_list; p != NULL; p = p->next)
+ if (p->state == nss_module_uninitialized)
+ p->state = nss_module_failed;
+
+ __libc_lock_unlock (nss_module_list_lock);
+}
+
void __libc_freeres_fn_section
__nss_module_freeres (void)
{
diff --git a/nss/nss_module.h b/nss/nss_module.h
index 06e8c29040..05c4791d11 100644
--- a/nss/nss_module.h
+++ b/nss/nss_module.h
@@ -87,6 +87,9 @@ bool __nss_module_load (struct nss_module *module) attribute_hidden;
void *__nss_module_get_function (struct nss_module *module, const char *name)
attribute_hidden;
+/* Block attempts to dlopen any module we haven't already opened. */
+void __nss_module_disable_loading (void);
+
/* Called from __libc_freeres. */
void __nss_module_freeres (void) attribute_hidden;
diff --git a/nss/tst-reload2.c b/nss/tst-reload2.c
new file mode 100644
index 0000000000..128db25ae6
--- /dev/null
+++ b/nss/tst-reload2.c
@@ -0,0 +1,126 @@
+/* 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>
diff --git a/nss/tst-reload2.root/etc/nsswitch.conf b/nss/tst-reload2.root/etc/nsswitch.conf
new file mode 100644
index 0000000000..570795ae22
--- /dev/null
+++ b/nss/tst-reload2.root/etc/nsswitch.conf
@@ -0,0 +1,2 @@
+passwd: test1
+group: test2
diff --git a/nss/tst-reload2.root/subdir/etc/group b/nss/tst-reload2.root/subdir/etc/group
new file mode 100644
index 0000000000..e48646bd47
--- /dev/null
+++ b/nss/tst-reload2.root/subdir/etc/group
@@ -0,0 +1 @@
+test3:x:123:
diff --git a/nss/tst-reload2.root/subdir/etc/nsswitch.conf b/nss/tst-reload2.root/subdir/etc/nsswitch.conf
new file mode 100644
index 0000000000..f1d73f8765
--- /dev/null
+++ b/nss/tst-reload2.root/subdir/etc/nsswitch.conf
@@ -0,0 +1,2 @@
+passwd: test2
+group: files
diff --git a/nss/tst-reload2.root/tst-reload2.script b/nss/tst-reload2.root/tst-reload2.script
new file mode 100644
index 0000000000..c6ee4b8e5e
--- /dev/null
+++ b/nss/tst-reload2.root/tst-reload2.script
@@ -0,0 +1,3 @@
+su
+cp $B/nss/libnss_test1.so $L/libnss_test1.so.2
+cp $B/nss/libnss_test2.so $L/libnss_test2.so.2
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-15 04:08:00 +0000