mirror of
https://github.com/torvalds/linux.git
synced 2026-05-13 08:39:31 +02:00
selftests/filesystems: add clone3 tests for empty mount namespaces
Add a test suite for the CLONE_EMPTY_MNTNS flag exercising the empty mount namespace functionality through the clone3() syscall. The clone3() code path is distinct from the unshare() path already tested in empty_mntns_test.c. With clone3(), CLONE_EMPTY_MNTNS (0x400000000ULL) is a 64-bit flag that implies CLONE_NEWNS. The implication happens in kernel_clone() before copy_process(), unlike unshare() where it goes through UNSHARE_EMPTY_MNTNS to CLONE_EMPTY_MNTNS conversion in unshare_nsproxy_namespaces(). The tests cover: - basic functionality: clone3 child gets empty mount namespace with exactly one mount, root and cwd point to the same mount - CLONE_NEWNS implication: CLONE_EMPTY_MNTNS works without explicit CLONE_NEWNS, also works with redundant CLONE_NEWNS - flag interactions: combines correctly with CLONE_NEWUSER, CLONE_NEWPID, CLONE_NEWUTS, CLONE_NEWIPC, CLONE_PIDFD - mutual exclusion: CLONE_EMPTY_MNTNS | CLONE_FS returns EINVAL because the implied CLONE_NEWNS conflicts with CLONE_FS - error paths: EPERM without capabilities, unknown 64-bit flags rejected - parent isolation: parent mount namespace is unchanged after clone - many parent mounts: child still gets exactly one mount - mount properties: root mount is nullfs, is its own parent, is the only listmount entry - overmount workflow: child can mount tmpfs over nullfs root to build a writable filesystem from scratch - repeated clone3: each child gets a distinct mount namespace - setns: parent can join child's empty mount namespace via setns() - regression: plain CLONE_NEWNS via clone3 still copies the full mount tree Link: https://patch.msgid.link/20260306-work-empty-mntns-consolidated-v1-3-6eb30529bbb0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner
parent
32f54f2bbc
commit
5b8ffd63fb
|
|
@ -1,3 +1,4 @@
|
|||
# SPDX-License-Identifier: GPL-2.0-only
|
||||
clone3_empty_mntns_test
|
||||
empty_mntns_test
|
||||
overmount_chroot_test
|
||||
|
|
|
|||
|
|
@ -3,9 +3,10 @@
|
|||
CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
|
||||
LDLIBS += -lcap
|
||||
|
||||
TEST_GEN_PROGS := empty_mntns_test overmount_chroot_test
|
||||
TEST_GEN_PROGS := empty_mntns_test overmount_chroot_test clone3_empty_mntns_test
|
||||
|
||||
include ../../lib.mk
|
||||
|
||||
$(OUTPUT)/empty_mntns_test: ../utils.c
|
||||
$(OUTPUT)/overmount_chroot_test: ../utils.c
|
||||
$(OUTPUT)/clone3_empty_mntns_test: ../utils.c
|
||||
|
|
|
|||
|
|
@ -0,0 +1,938 @@
|
|||
// SPDX-License-Identifier: GPL-2.0-or-later
|
||||
/*
|
||||
* Tests for empty mount namespace creation via clone3() CLONE_EMPTY_MNTNS
|
||||
*
|
||||
* These tests exercise the clone3() code path for creating empty mount
|
||||
* namespaces, which is distinct from the unshare() path tested in
|
||||
* empty_mntns_test.c. With clone3(), CLONE_EMPTY_MNTNS (0x400000000ULL)
|
||||
* is a 64-bit flag that implies CLONE_NEWNS. The implication happens in
|
||||
* kernel_clone() before copy_process(), unlike unshare() where it goes
|
||||
* through UNSHARE_EMPTY_MNTNS -> CLONE_EMPTY_MNTNS conversion in
|
||||
* unshare_nsproxy_namespaces().
|
||||
*
|
||||
* Copyright (c) 2024 Christian Brauner <brauner@kernel.org>
|
||||
*/
|
||||
|
||||
#define _GNU_SOURCE
|
||||
#include <fcntl.h>
|
||||
#include <linux/mount.h>
|
||||
#include <linux/stat.h>
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <sys/mount.h>
|
||||
#include <sys/stat.h>
|
||||
#include <sys/types.h>
|
||||
#include <unistd.h>
|
||||
|
||||
#include "../utils.h"
|
||||
#include "../wrappers.h"
|
||||
#include "clone3/clone3_selftests.h"
|
||||
#include "empty_mntns.h"
|
||||
#include "kselftest_harness.h"
|
||||
|
||||
static pid_t clone3_empty_mntns(uint64_t extra_flags)
|
||||
{
|
||||
struct __clone_args args = {
|
||||
.flags = CLONE_EMPTY_MNTNS | extra_flags,
|
||||
.exit_signal = SIGCHLD,
|
||||
};
|
||||
|
||||
return sys_clone3(&args, sizeof(args));
|
||||
}
|
||||
|
||||
static bool clone3_empty_mntns_supported(void)
|
||||
{
|
||||
pid_t pid;
|
||||
int status;
|
||||
|
||||
pid = fork();
|
||||
if (pid < 0)
|
||||
return false;
|
||||
|
||||
if (pid == 0) {
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
pid = clone3_empty_mntns(0);
|
||||
if (pid < 0)
|
||||
_exit(1);
|
||||
|
||||
if (pid == 0)
|
||||
_exit(0);
|
||||
|
||||
_exit(wait_for_pid(pid) != 0);
|
||||
}
|
||||
|
||||
if (waitpid(pid, &status, 0) != pid)
|
||||
return false;
|
||||
|
||||
if (!WIFEXITED(status))
|
||||
return false;
|
||||
|
||||
return WEXITSTATUS(status) == 0;
|
||||
}
|
||||
|
||||
FIXTURE(clone3_empty_mntns) {};
|
||||
|
||||
FIXTURE_SETUP(clone3_empty_mntns)
|
||||
{
|
||||
if (!clone3_empty_mntns_supported())
|
||||
SKIP(return, "CLONE_EMPTY_MNTNS via clone3 not supported");
|
||||
}
|
||||
|
||||
FIXTURE_TEARDOWN(clone3_empty_mntns) {}
|
||||
|
||||
/*
|
||||
* Basic clone3() with CLONE_EMPTY_MNTNS: child gets empty mount namespace
|
||||
* with exactly 1 mount and root == cwd.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, basic)
|
||||
{
|
||||
pid_t pid, inner;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(2);
|
||||
|
||||
if (inner == 0) {
|
||||
uint64_t root_id, cwd_id;
|
||||
|
||||
if (count_mounts() != 1)
|
||||
_exit(3);
|
||||
|
||||
root_id = get_unique_mnt_id("/");
|
||||
cwd_id = get_unique_mnt_id(".");
|
||||
if (root_id == 0 || cwd_id == 0)
|
||||
_exit(4);
|
||||
|
||||
if (root_id != cwd_id)
|
||||
_exit(5);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* CLONE_EMPTY_MNTNS implies CLONE_NEWNS. Verify that it works without
|
||||
* explicitly setting CLONE_NEWNS (tests fork.c:2627-2630).
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, implies_newns)
|
||||
{
|
||||
pid_t pid, inner;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
ssize_t parent_mounts;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
/* Verify we have mounts in our current namespace. */
|
||||
parent_mounts = count_mounts();
|
||||
if (parent_mounts < 1)
|
||||
_exit(2);
|
||||
|
||||
/* Only CLONE_EMPTY_MNTNS, no explicit CLONE_NEWNS. */
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(3);
|
||||
|
||||
if (inner == 0) {
|
||||
if (count_mounts() != 1)
|
||||
_exit(4);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
/* Parent still has its mounts. */
|
||||
if (count_mounts() != parent_mounts)
|
||||
_exit(5);
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Helper macro: generate a test that clones with CLONE_EMPTY_MNTNS |
|
||||
* @extra_flags and verifies the child has exactly one mount.
|
||||
*/
|
||||
#define TEST_CLONE3_FLAGS(test_name, extra_flags) \
|
||||
TEST_F(clone3_empty_mntns, test_name) \
|
||||
{ \
|
||||
pid_t pid, inner; \
|
||||
\
|
||||
pid = fork(); \
|
||||
ASSERT_GE(pid, 0); \
|
||||
\
|
||||
if (pid == 0) { \
|
||||
if (enter_userns()) \
|
||||
_exit(1); \
|
||||
\
|
||||
inner = clone3_empty_mntns(extra_flags); \
|
||||
if (inner < 0) \
|
||||
_exit(2); \
|
||||
\
|
||||
if (inner == 0) { \
|
||||
if (count_mounts() != 1) \
|
||||
_exit(3); \
|
||||
_exit(0); \
|
||||
} \
|
||||
\
|
||||
_exit(wait_for_pid(inner)); \
|
||||
} \
|
||||
\
|
||||
ASSERT_EQ(wait_for_pid(pid), 0); \
|
||||
}
|
||||
|
||||
/* Redundant CLONE_NEWNS | CLONE_EMPTY_MNTNS should succeed. */
|
||||
TEST_CLONE3_FLAGS(with_explicit_newns, CLONE_NEWNS)
|
||||
|
||||
/* CLONE_EMPTY_MNTNS combined with CLONE_NEWUSER. */
|
||||
TEST_CLONE3_FLAGS(with_newuser, CLONE_NEWUSER)
|
||||
|
||||
/* CLONE_EMPTY_MNTNS combined with other namespace flags. */
|
||||
TEST_CLONE3_FLAGS(with_other_ns_flags, CLONE_NEWUTS | CLONE_NEWIPC)
|
||||
|
||||
/*
|
||||
* CLONE_EMPTY_MNTNS combined with CLONE_NEWPID.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, with_newpid)
|
||||
{
|
||||
pid_t pid, inner;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
inner = clone3_empty_mntns(CLONE_NEWPID);
|
||||
if (inner < 0)
|
||||
_exit(2);
|
||||
|
||||
if (inner == 0) {
|
||||
if (count_mounts() != 1)
|
||||
_exit(3);
|
||||
|
||||
/* In a new PID namespace, getpid() returns 1. */
|
||||
if (getpid() != 1)
|
||||
_exit(4);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* CLONE_EMPTY_MNTNS | CLONE_FS must fail because the implied CLONE_NEWNS
|
||||
* and CLONE_FS are mutually exclusive (fork.c:1981).
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, with_clone_fs_fails)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
struct __clone_args args = {
|
||||
.flags = CLONE_EMPTY_MNTNS | CLONE_FS,
|
||||
.exit_signal = SIGCHLD,
|
||||
};
|
||||
pid_t ret;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
ret = sys_clone3(&args, sizeof(args));
|
||||
if (ret >= 0) {
|
||||
if (ret == 0)
|
||||
_exit(0);
|
||||
wait_for_pid(ret);
|
||||
_exit(2);
|
||||
}
|
||||
|
||||
if (errno != EINVAL)
|
||||
_exit(3);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* CLONE_EMPTY_MNTNS combined with CLONE_PIDFD returns a valid pidfd.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, with_pidfd)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
struct __clone_args args = {
|
||||
.flags = CLONE_EMPTY_MNTNS | CLONE_PIDFD,
|
||||
.exit_signal = SIGCHLD,
|
||||
};
|
||||
int pidfd = -1;
|
||||
pid_t inner;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
args.pidfd = (uintptr_t)&pidfd;
|
||||
|
||||
inner = sys_clone3(&args, sizeof(args));
|
||||
if (inner < 0)
|
||||
_exit(2);
|
||||
|
||||
if (inner == 0) {
|
||||
if (count_mounts() != 1)
|
||||
_exit(3);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
/* Verify we got a valid pidfd. */
|
||||
if (pidfd < 0)
|
||||
_exit(4);
|
||||
|
||||
close(pidfd);
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* clone3 without CAP_SYS_ADMIN must fail with EPERM.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, eperm_without_caps)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
pid_t ret;
|
||||
|
||||
/* Skip if already root. */
|
||||
if (getuid() == 0)
|
||||
_exit(0);
|
||||
|
||||
ret = clone3_empty_mntns(0);
|
||||
if (ret >= 0) {
|
||||
if (ret == 0)
|
||||
_exit(0);
|
||||
wait_for_pid(ret);
|
||||
_exit(1);
|
||||
}
|
||||
|
||||
if (errno != EPERM)
|
||||
_exit(2);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Parent's mount namespace is unaffected after clone3 with CLONE_EMPTY_MNTNS.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, parent_unchanged)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
ssize_t nr_before, nr_after;
|
||||
pid_t inner;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
nr_before = count_mounts();
|
||||
if (nr_before < 1)
|
||||
_exit(2);
|
||||
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(3);
|
||||
|
||||
if (inner == 0)
|
||||
_exit(0);
|
||||
|
||||
if (wait_for_pid(inner) != 0)
|
||||
_exit(4);
|
||||
|
||||
nr_after = count_mounts();
|
||||
if (nr_after != nr_before)
|
||||
_exit(5);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Parent with many mounts: child still gets exactly 1 mount.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, many_parent_mounts)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
char tmpdir[] = "/tmp/clone3_mntns_test.XXXXXX";
|
||||
pid_t inner;
|
||||
int i;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
if (unshare(CLONE_NEWNS))
|
||||
_exit(2);
|
||||
|
||||
if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL))
|
||||
_exit(3);
|
||||
|
||||
if (!mkdtemp(tmpdir))
|
||||
_exit(4);
|
||||
|
||||
if (mount("tmpfs", tmpdir, "tmpfs", 0, "size=1M"))
|
||||
_exit(5);
|
||||
|
||||
for (i = 0; i < 5; i++) {
|
||||
char subdir[256];
|
||||
|
||||
snprintf(subdir, sizeof(subdir), "%s/sub%d", tmpdir, i);
|
||||
if (mkdir(subdir, 0755) && errno != EEXIST)
|
||||
_exit(6);
|
||||
if (mount(subdir, subdir, NULL, MS_BIND, NULL))
|
||||
_exit(7);
|
||||
}
|
||||
|
||||
if (count_mounts() < 5)
|
||||
_exit(8);
|
||||
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(9);
|
||||
|
||||
if (inner == 0) {
|
||||
if (count_mounts() != 1)
|
||||
_exit(10);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Verify the child's root mount is nullfs with expected statmount properties.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, mount_properties)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
pid_t inner;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(2);
|
||||
|
||||
if (inner == 0) {
|
||||
struct statmount *sm;
|
||||
uint64_t root_id;
|
||||
|
||||
root_id = get_unique_mnt_id("/");
|
||||
if (!root_id)
|
||||
_exit(3);
|
||||
|
||||
sm = statmount_alloc(root_id, 0,
|
||||
STATMOUNT_MNT_BASIC |
|
||||
STATMOUNT_MNT_POINT |
|
||||
STATMOUNT_FS_TYPE);
|
||||
if (!sm)
|
||||
_exit(4);
|
||||
|
||||
/* Root mount point is "/". */
|
||||
if (!(sm->mask & STATMOUNT_MNT_POINT))
|
||||
_exit(5);
|
||||
if (strcmp(sm->str + sm->mnt_point, "/") != 0)
|
||||
_exit(6);
|
||||
|
||||
/* Filesystem type is nullfs. */
|
||||
if (!(sm->mask & STATMOUNT_FS_TYPE))
|
||||
_exit(7);
|
||||
if (strcmp(sm->str + sm->fs_type, "nullfs") != 0)
|
||||
_exit(8);
|
||||
|
||||
/* Root mount is its own parent. */
|
||||
if (!(sm->mask & STATMOUNT_MNT_BASIC))
|
||||
_exit(9);
|
||||
if (sm->mnt_parent_id != sm->mnt_id)
|
||||
_exit(10);
|
||||
|
||||
free(sm);
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Listmount returns only the root mount in the child's empty namespace.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, listmount_single_entry)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
pid_t inner;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(2);
|
||||
|
||||
if (inner == 0) {
|
||||
uint64_t list[16];
|
||||
ssize_t nr_mounts;
|
||||
uint64_t root_id;
|
||||
|
||||
nr_mounts = listmount(LSMT_ROOT, 0, 0, list, 16, 0);
|
||||
if (nr_mounts != 1)
|
||||
_exit(3);
|
||||
|
||||
root_id = get_unique_mnt_id("/");
|
||||
if (!root_id)
|
||||
_exit(4);
|
||||
|
||||
if (list[0] != root_id)
|
||||
_exit(5);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Child can mount tmpfs over nullfs root (the primary container use case).
|
||||
*
|
||||
* Uses the new mount API (fsopen/fsmount/move_mount) because resolving
|
||||
* "/" returns the process root directly without following overmounts.
|
||||
* The mount fd from fsmount lets us fchdir + chroot into the new tmpfs.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, child_overmount_tmpfs)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
pid_t inner;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(2);
|
||||
|
||||
if (inner == 0) {
|
||||
struct statmount *sm;
|
||||
uint64_t root_id;
|
||||
int fd, fsfd, mntfd;
|
||||
|
||||
if (count_mounts() != 1)
|
||||
_exit(3);
|
||||
|
||||
/* Verify root is nullfs. */
|
||||
root_id = get_unique_mnt_id("/");
|
||||
if (!root_id)
|
||||
_exit(4);
|
||||
|
||||
sm = statmount_alloc(root_id, 0, STATMOUNT_FS_TYPE);
|
||||
if (!sm)
|
||||
_exit(5);
|
||||
if (!(sm->mask & STATMOUNT_FS_TYPE))
|
||||
_exit(6);
|
||||
if (strcmp(sm->str + sm->fs_type, "nullfs") != 0)
|
||||
_exit(7);
|
||||
free(sm);
|
||||
|
||||
/* Create tmpfs via the new mount API. */
|
||||
fsfd = sys_fsopen("tmpfs", 0);
|
||||
if (fsfd < 0)
|
||||
_exit(8);
|
||||
|
||||
if (sys_fsconfig(fsfd, FSCONFIG_SET_STRING,
|
||||
"size", "1M", 0)) {
|
||||
close(fsfd);
|
||||
_exit(9);
|
||||
}
|
||||
|
||||
if (sys_fsconfig(fsfd, FSCONFIG_CMD_CREATE,
|
||||
NULL, NULL, 0)) {
|
||||
close(fsfd);
|
||||
_exit(10);
|
||||
}
|
||||
|
||||
mntfd = sys_fsmount(fsfd, 0, 0);
|
||||
close(fsfd);
|
||||
if (mntfd < 0)
|
||||
_exit(11);
|
||||
|
||||
/* Attach tmpfs to "/". */
|
||||
if (sys_move_mount(mntfd, "", AT_FDCWD, "/",
|
||||
MOVE_MOUNT_F_EMPTY_PATH)) {
|
||||
close(mntfd);
|
||||
_exit(12);
|
||||
}
|
||||
|
||||
if (count_mounts() != 2) {
|
||||
close(mntfd);
|
||||
_exit(13);
|
||||
}
|
||||
|
||||
/* Enter the tmpfs. */
|
||||
if (fchdir(mntfd)) {
|
||||
close(mntfd);
|
||||
_exit(14);
|
||||
}
|
||||
|
||||
if (chroot(".")) {
|
||||
close(mntfd);
|
||||
_exit(15);
|
||||
}
|
||||
|
||||
close(mntfd);
|
||||
|
||||
/* Verify "/" is now tmpfs. */
|
||||
root_id = get_unique_mnt_id("/");
|
||||
if (!root_id)
|
||||
_exit(16);
|
||||
|
||||
sm = statmount_alloc(root_id, 0, STATMOUNT_FS_TYPE);
|
||||
if (!sm)
|
||||
_exit(17);
|
||||
if (!(sm->mask & STATMOUNT_FS_TYPE))
|
||||
_exit(18);
|
||||
if (strcmp(sm->str + sm->fs_type, "tmpfs") != 0)
|
||||
_exit(19);
|
||||
free(sm);
|
||||
|
||||
/* Verify tmpfs is writable. */
|
||||
fd = open("/testfile", O_CREAT | O_RDWR, 0644);
|
||||
if (fd < 0)
|
||||
_exit(20);
|
||||
|
||||
if (write(fd, "test", 4) != 4) {
|
||||
close(fd);
|
||||
_exit(21);
|
||||
}
|
||||
close(fd);
|
||||
|
||||
if (access("/testfile", F_OK))
|
||||
_exit(22);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Multiple clone3 calls with CLONE_EMPTY_MNTNS produce children with
|
||||
* distinct mount namespace root mount IDs.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, repeated)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
int pipe1[2], pipe2[2];
|
||||
uint64_t id1 = 0, id2 = 0;
|
||||
pid_t inner1, inner2;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
if (pipe(pipe1) || pipe(pipe2))
|
||||
_exit(2);
|
||||
|
||||
inner1 = clone3_empty_mntns(0);
|
||||
if (inner1 < 0)
|
||||
_exit(3);
|
||||
|
||||
if (inner1 == 0) {
|
||||
uint64_t root_id;
|
||||
|
||||
close(pipe1[0]);
|
||||
root_id = get_unique_mnt_id("/");
|
||||
if (write(pipe1[1], &root_id, sizeof(root_id)) != sizeof(root_id))
|
||||
_exit(1);
|
||||
close(pipe1[1]);
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
inner2 = clone3_empty_mntns(0);
|
||||
if (inner2 < 0)
|
||||
_exit(4);
|
||||
|
||||
if (inner2 == 0) {
|
||||
uint64_t root_id;
|
||||
|
||||
close(pipe2[0]);
|
||||
root_id = get_unique_mnt_id("/");
|
||||
if (write(pipe2[1], &root_id, sizeof(root_id)) != sizeof(root_id))
|
||||
_exit(1);
|
||||
close(pipe2[1]);
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
close(pipe1[1]);
|
||||
close(pipe2[1]);
|
||||
|
||||
if (read(pipe1[0], &id1, sizeof(id1)) != sizeof(id1))
|
||||
_exit(5);
|
||||
if (read(pipe2[0], &id2, sizeof(id2)) != sizeof(id2))
|
||||
_exit(6);
|
||||
|
||||
close(pipe1[0]);
|
||||
close(pipe2[0]);
|
||||
|
||||
if (wait_for_pid(inner1) || wait_for_pid(inner2))
|
||||
_exit(7);
|
||||
|
||||
/* Each child must have a distinct root mount ID. */
|
||||
if (id1 == 0 || id2 == 0)
|
||||
_exit(8);
|
||||
if (id1 == id2)
|
||||
_exit(9);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Verify setns() into a child's empty mount namespace works.
|
||||
*/
|
||||
TEST_F(clone3_empty_mntns, setns_into_child_mntns)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
int pipe_fd[2];
|
||||
pid_t inner;
|
||||
char c;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
if (pipe(pipe_fd))
|
||||
_exit(2);
|
||||
|
||||
inner = clone3_empty_mntns(0);
|
||||
if (inner < 0)
|
||||
_exit(3);
|
||||
|
||||
if (inner == 0) {
|
||||
/* Signal parent we're ready. */
|
||||
close(pipe_fd[0]);
|
||||
if (write(pipe_fd[1], "r", 1) != 1)
|
||||
_exit(1);
|
||||
|
||||
/*
|
||||
* Wait for parent to finish. Reading from our
|
||||
* write end will block until the parent closes
|
||||
* its read end, giving us an implicit barrier.
|
||||
*/
|
||||
if (read(pipe_fd[1], &c, 1) < 0)
|
||||
;
|
||||
close(pipe_fd[1]);
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
close(pipe_fd[1]);
|
||||
|
||||
/* Wait for child to be ready. */
|
||||
if (read(pipe_fd[0], &c, 1) != 1)
|
||||
_exit(4);
|
||||
|
||||
/* Open child's mount namespace. */
|
||||
{
|
||||
char path[64];
|
||||
int mntns_fd;
|
||||
|
||||
snprintf(path, sizeof(path), "/proc/%d/ns/mnt", inner);
|
||||
mntns_fd = open(path, O_RDONLY);
|
||||
if (mntns_fd < 0)
|
||||
_exit(5);
|
||||
|
||||
if (setns(mntns_fd, CLONE_NEWNS))
|
||||
_exit(6);
|
||||
|
||||
close(mntns_fd);
|
||||
}
|
||||
|
||||
/* Now we should be in the child's empty mntns. */
|
||||
if (count_mounts() != 1)
|
||||
_exit(7);
|
||||
|
||||
close(pipe_fd[0]);
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Tests below do not require CLONE_EMPTY_MNTNS support.
|
||||
*/
|
||||
|
||||
/*
|
||||
* Unknown 64-bit flags beyond the known set are rejected.
|
||||
*/
|
||||
TEST(unknown_flags_rejected)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
struct __clone_args args = {
|
||||
.flags = 0x800000000ULL,
|
||||
.exit_signal = SIGCHLD,
|
||||
};
|
||||
pid_t ret;
|
||||
|
||||
ret = sys_clone3(&args, sizeof(args));
|
||||
if (ret >= 0) {
|
||||
if (ret == 0)
|
||||
_exit(0);
|
||||
wait_for_pid(ret);
|
||||
_exit(1);
|
||||
}
|
||||
|
||||
if (errno != EINVAL)
|
||||
_exit(2);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Regular clone3 with CLONE_NEWNS (without CLONE_EMPTY_MNTNS) still
|
||||
* copies the full mount tree.
|
||||
*/
|
||||
TEST(clone3_newns_full_copy)
|
||||
{
|
||||
pid_t pid;
|
||||
|
||||
pid = fork();
|
||||
ASSERT_GE(pid, 0);
|
||||
|
||||
if (pid == 0) {
|
||||
struct __clone_args args = {
|
||||
.flags = CLONE_NEWNS,
|
||||
.exit_signal = SIGCHLD,
|
||||
};
|
||||
ssize_t parent_mounts;
|
||||
pid_t inner;
|
||||
|
||||
if (enter_userns())
|
||||
_exit(1);
|
||||
|
||||
parent_mounts = count_mounts();
|
||||
if (parent_mounts < 1)
|
||||
_exit(2);
|
||||
|
||||
inner = sys_clone3(&args, sizeof(args));
|
||||
if (inner < 0)
|
||||
_exit(3);
|
||||
|
||||
if (inner == 0) {
|
||||
/* Full copy should have at least as many mounts. */
|
||||
if (count_mounts() < parent_mounts)
|
||||
_exit(1);
|
||||
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
_exit(wait_for_pid(inner));
|
||||
}
|
||||
|
||||
ASSERT_EQ(wait_for_pid(pid), 0);
|
||||
}
|
||||
|
||||
TEST_HARNESS_MAIN
|
||||
Loading…
Reference in New Issue
Block a user