[LTP] [ltp][PATCH v3] Add ltp pivot_root test
Paul Lawrence
paullawrence@google.com
Tue Mar 5 19:44:55 CET 2019
Fixed too long line
Added const to static struct test_case
Made fail with TCONF when HAVE_LIBCAP not defined
Signed-off-by: Paul Lawrence <paullawrence@google.com>
---
runtest/syscalls | 2 +
testcases/kernel/syscalls/pivot_root/Makefile | 11 +
.../kernel/syscalls/pivot_root/pivot_root01.c | 200 ++++++++++++++++++
3 files changed, 213 insertions(+)
create mode 100644 testcases/kernel/syscalls/pivot_root/Makefile
create mode 100644 testcases/kernel/syscalls/pivot_root/pivot_root01.c
diff --git a/runtest/syscalls b/runtest/syscalls
index 668c87cd1..debda74b8 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -835,6 +835,8 @@ pipe11 pipe11
pipe2_01 pipe2_01
pipe2_02 pipe2_02
+pivot_root01 pivot_root01
+
poll01 poll01
poll02 poll02
diff --git a/testcases/kernel/syscalls/pivot_root/Makefile b/testcases/kernel/syscalls/pivot_root/Makefile
new file mode 100644
index 000000000..a16974d41
--- /dev/null
+++ b/testcases/kernel/syscalls/pivot_root/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright (c) 2019 Google, Inc.
+
+top_srcdir ?= ../../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+
+LDLIBS := $(LDLIBS) $(CAP_LIBS)
+
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/syscalls/pivot_root/pivot_root01.c b/testcases/kernel/syscalls/pivot_root/pivot_root01.c
new file mode 100644
index 000000000..c78428a91
--- /dev/null
+++ b/testcases/kernel/syscalls/pivot_root/pivot_root01.c
@@ -0,0 +1,200 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Copyright (c) 2019 Google, Inc.
+ */
+
+#define _GNU_SOURCE
+
+#include <config.h>
+
+#include <errno.h>
+#include <linux/unistd.h>
+#include <sched.h>
+
+#include <sys/mount.h>
+#include <stdlib.h>
+
+#include "tst_test.h"
+
+#ifdef HAVE_LIBCAP
+#include <sys/capability.h>
+#endif
+
+static const char* chroot_dir = "chroot";
+static const char* new_root = "/new_root";
+static const char* put_old = "/new_root/put_old";
+static const char* put_old_fs = "/put_old_fs";
+static const char* put_old_bad = "/put_old_fs/put_old";
+
+/*
+ * Test consists of a series of steps that allow pivot_root to succeed, which
+ * is run when param is NORMAL. All other values tweak one of the steps to
+ * induce a failure, and check the errno is as expected.
+ */
+#define NORMAL 0
+
+/*
+ * EBUSY
+ * new_root or put_old are on the current root file system
+ */
+#define NEW_ROOT_ON_CURRENT_ROOT 1
+
+/*
+ * EINVAL
+ * put_old is not underneath new_root
+ * Note: if put_old and new_root are on the same fs,
+ * pivot_root fails with EBUSY before testing reachability
+ */
+#define PUT_OLD_NOT_UNDERNEATH_NEW_ROOT 2
+
+/*
+ * ENOTDIR
+ * new_root or put_old is not a directory
+ */
+#define PUT_OLD_NOT_DIR 3
+
+/*
+ * EPERM
+ * The calling process does not have the CAP_SYS_ADMIN capability.
+ */
+#define NO_CAP_SYS_ADMIN 4
+
+static const struct test_case {
+ int test_case;
+ int expected_error;
+} test_cases[] = {
+ {NORMAL, 0},
+ {NEW_ROOT_ON_CURRENT_ROOT, EBUSY},
+ {PUT_OLD_NOT_UNDERNEATH_NEW_ROOT, EINVAL},
+ {PUT_OLD_NOT_DIR, ENOTDIR},
+ {NO_CAP_SYS_ADMIN, EPERM},
+};
+
+#ifdef HAVE_LIBCAP
+static void drop_cap_sys_admin(void)
+{
+ cap_value_t cap_value[] = { CAP_SYS_ADMIN };
+ cap_t cap = cap_get_proc();
+ if (!cap)
+ tst_brk(TFAIL | TERRNO, "cap_get_proc failed");
+
+ if (cap_set_flag(cap, CAP_EFFECTIVE, 1, cap_value, CAP_CLEAR))
+ tst_brk(TFAIL | TERRNO, "cap_set_flag failed");
+
+ if (cap_set_proc(cap))
+ tst_brk(TFAIL | TERRNO, "cap_set_proc failed");
+}
+#endif
+
+#ifdef HAVE_UNSHARE
+static void run(unsigned int test_case)
+{
+ /* Work in child process - needed to undo unshare and chroot */
+ if (SAFE_FORK()) {
+ tst_reap_children();
+ return;
+ }
+
+ /* pivot_root requires no shared mounts exist in process namespace */
+ TEST(unshare(CLONE_NEWNS | CLONE_FS));
+ if (TST_RET == -1)
+ tst_brk(TFAIL | TERRNO, "unshare failed");
+
+ /*
+ * Create an initial root dir. pivot_root doesn't work if the initial root
+ * dir is a initramfs, so use chroot to create a safe environment
+ */
+ SAFE_MOUNT("none", "/", NULL, MS_REC|MS_PRIVATE, NULL);
+ SAFE_MOUNT("none", chroot_dir, "tmpfs", 0, 0);
+ SAFE_CHROOT(chroot_dir);
+
+ /* Create our new root location */
+ SAFE_MKDIR(new_root, 0777);
+
+ /*
+ * pivot_root only works if new_root is a mount point, so mount a tmpfs
+ * unless testing for that fail mode
+ */
+ if (test_cases[test_case].test_case != NEW_ROOT_ON_CURRENT_ROOT)
+ SAFE_MOUNT("none", new_root, "tmpfs", 0, 0);
+
+ /*
+ * Create put_old under new_root, unless testing for that specific fail
+ * mode
+ */
+ const char* actual_put_old = NULL;
+ if (test_cases[test_case].test_case == PUT_OLD_NOT_UNDERNEATH_NEW_ROOT) {
+ actual_put_old = put_old_bad;
+ SAFE_MKDIR(put_old_fs, 0777);
+ SAFE_MOUNT("none", put_old_fs, "tmpfs", 0, 0);
+ SAFE_MKDIR(put_old_bad, 0777);
+ } else {
+ actual_put_old = put_old;
+
+ /* put_old must be a directory for success */
+ if (test_cases[test_case].test_case == PUT_OLD_NOT_DIR)
+ SAFE_CREAT(put_old, 0777);
+ else
+ SAFE_MKDIR(put_old, 0777);
+ }
+
+ if (test_cases[test_case].test_case == NO_CAP_SYS_ADMIN)
+#ifdef HAVE_LIBCAP
+ drop_cap_sys_admin();
+#else
+ tst_brk(TCONF,
+ "System doesn't have POSIX capabilities support");
+#endif
+
+ /* Test the syscall */
+ TEST(syscall(__NR_pivot_root, new_root, actual_put_old));
+
+ /* If NORMAL it should have succeeded */
+ if (test_cases[test_case].test_case == NORMAL) {
+ if (TST_RET) {
+ tst_res(TFAIL | TERRNO, "pivot_root failed");
+ exit(TBROK);
+ } else {
+ tst_res(TPASS, "pivot_root succeeded");
+ exit(TPASS);
+ }
+ }
+
+ /* pivot_root is expected to fail */
+ if (TST_RET == 0) {
+ tst_res(TFAIL, "pivot_root succeeded unexpectedly");
+ exit(TBROK);
+ }
+
+ /* Check error code is correct */
+ if (errno != test_cases[test_case].expected_error) {
+ tst_res(TFAIL | TERRNO, "pivot_root failed with wrong errno");
+ exit(TBROK);
+ }
+
+ tst_res(TPASS, "pivot_root failed as expected with %s",
+ strerror(errno));
+ exit(TPASS);
+}
+
+#else
+static void run(void)
+{
+ tst_brk(TCONF, NULL, "unshare is undefined.");
+}
+#endif
+
+static void setup(void)
+{
+ SAFE_MKDIR(chroot_dir, 0777);
+}
+
+static struct tst_test test = {
+ .test = run,
+ .tcnt = ARRAY_SIZE(test_cases),
+ .needs_tmpdir = 1,
+ .needs_root = 1,
+ .forks_child = 1,
+ .setup = setup,
+};
--
2.21.0.352.gf09ad66450-goog
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