// SPDX-License-Identifier: GPL-2.0-or-later/* * Author: Aleksa Sarai <cyphar@cyphar.com> * Copyright (C) 2025 SUSE LLC. */ #include <assert.h>#include <errno.h>#include <fcntl.h>#include <sched.h>#include <stdbool.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <stdio.h>#include <sys/mount.h>#include <sys/stat.h>#include <sys/prctl.h> #include "kselftest_harness.h" #define ASSERT_ERRNO(expected, _t, seen)				\	__EXPECT(expected, #expected,					\		({__typeof__(seen) _tmp_seen = (seen);			\		  _tmp_seen >= 0 ? _tmp_seen : -errno; }), #seen, _t, 1) #define ASSERT_ERRNO_EQ(expected, seen) \	ASSERT_ERRNO(expected, ==, seen) #define ASSERT_SUCCESS(seen) \	ASSERT_ERRNO(0, <=, seen) static int touch(char *path){	int fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC, 0644);	if (fd < 0)		return -1;	return close(fd);} FIXTURE(ns){	int host_mntns, host_pidns;	int dummy_pidns;}; FIXTURE_SETUP(ns){	/* Stash the old mntns. */	self->host_mntns = open("/proc/self/ns/mnt", O_RDONLY|O_CLOEXEC);	ASSERT_SUCCESS(self->host_mntns); 	/* Create a new mount namespace and make it private. */	ASSERT_SUCCESS(unshare(CLONE_NEWNS));	ASSERT_SUCCESS(mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL)); 	/*	 * Create a proper tmpfs that we can use and will disappear once we	 * leave this mntns.	 */	ASSERT_SUCCESS(mount("tmpfs", "/tmp", "tmpfs", 0, NULL)); 	/*	 * Create a pidns we can use for later tests. We need to fork off a	 * child so that we get a usable nsfd that we can bind-mount and open.	 */	ASSERT_SUCCESS(mkdir("/tmp/dummy", 0755));	ASSERT_SUCCESS(touch("/tmp/dummy/pidns"));	ASSERT_SUCCESS(mkdir("/tmp/dummy/proc", 0755)); 	self->host_pidns = open("/proc/self/ns/pid", O_RDONLY|O_CLOEXEC);	ASSERT_SUCCESS(self->host_pidns);	ASSERT_SUCCESS(unshare(CLONE_NEWPID)); 	pid_t pid = fork();	ASSERT_SUCCESS(pid);	if (!pid) {		prctl(PR_SET_PDEATHSIG, SIGKILL);		ASSERT_SUCCESS(mount("/proc/self/ns/pid", "/tmp/dummy/pidns", NULL, MS_BIND, NULL));		ASSERT_SUCCESS(mount("proc", "/tmp/dummy/proc", "proc", 0, NULL));		exit(0);	} 	int wstatus;	ASSERT_EQ(waitpid(pid, &wstatus, 0), pid);	ASSERT_TRUE(WIFEXITED(wstatus));	ASSERT_EQ(WEXITSTATUS(wstatus), 0); 	ASSERT_SUCCESS(setns(self->host_pidns, CLONE_NEWPID)); 	self->dummy_pidns = open("/tmp/dummy/pidns", O_RDONLY|O_CLOEXEC);	ASSERT_SUCCESS(self->dummy_pidns);} FIXTURE_TEARDOWN(ns){	ASSERT_SUCCESS(setns(self->host_mntns, CLONE_NEWNS));	ASSERT_SUCCESS(close(self->host_mntns)); 	ASSERT_SUCCESS(close(self->host_pidns));	ASSERT_SUCCESS(close(self->dummy_pidns));} TEST_F(ns, pidns_mount_string_path){	ASSERT_SUCCESS(mkdir("/tmp/proc-host", 0755));	ASSERT_SUCCESS(mount("proc", "/tmp/proc-host", "proc", 0, "pidns=/proc/self/ns/pid"));	ASSERT_SUCCESS(access("/tmp/proc-host/self/", X_OK)); 	ASSERT_SUCCESS(mkdir("/tmp/proc-dummy", 0755));	ASSERT_SUCCESS(mount("proc", "/tmp/proc-dummy", "proc", 0, "pidns=/tmp/dummy/pidns"));	ASSERT_ERRNO_EQ(-ENOENT, access("/tmp/proc-dummy/1/", X_OK));	ASSERT_ERRNO_EQ(-ENOENT, access("/tmp/proc-dummy/self/", X_OK));} TEST_F(ns, pidns_fsconfig_string_path){	int fsfd = fsopen("proc", FSOPEN_CLOEXEC);	ASSERT_SUCCESS(fsfd); 	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_SET_STRING, "pidns", "/tmp/dummy/pidns", 0));	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0)); 	int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);	ASSERT_SUCCESS(mountfd); 	ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "1/", X_OK, 0));	ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "self/", X_OK, 0)); 	ASSERT_SUCCESS(close(fsfd));	ASSERT_SUCCESS(close(mountfd));} TEST_F(ns, pidns_fsconfig_fd){	int fsfd = fsopen("proc", FSOPEN_CLOEXEC);	ASSERT_SUCCESS(fsfd); 	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_SET_FD, "pidns", NULL, self->dummy_pidns));	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0)); 	int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);	ASSERT_SUCCESS(mountfd); 	ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "1/", X_OK, 0));	ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "self/", X_OK, 0)); 	ASSERT_SUCCESS(close(fsfd));	ASSERT_SUCCESS(close(mountfd));} TEST_F(ns, pidns_reconfigure_remount){	ASSERT_SUCCESS(mkdir("/tmp/proc", 0755));	ASSERT_SUCCESS(mount("proc", "/tmp/proc", "proc", 0, "")); 	ASSERT_SUCCESS(access("/tmp/proc/1/", X_OK));	ASSERT_SUCCESS(access("/tmp/proc/self/", X_OK)); 	ASSERT_ERRNO_EQ(-EBUSY, mount(NULL, "/tmp/proc", NULL, MS_REMOUNT, "pidns=/tmp/dummy/pidns")); 	ASSERT_SUCCESS(access("/tmp/proc/1/", X_OK));	ASSERT_SUCCESS(access("/tmp/proc/self/", X_OK));} TEST_F(ns, pidns_reconfigure_fsconfig_string_path){	int fsfd = fsopen("proc", FSOPEN_CLOEXEC);	ASSERT_SUCCESS(fsfd); 	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0)); 	int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);	ASSERT_SUCCESS(mountfd); 	ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));	ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0)); 	ASSERT_ERRNO_EQ(-EBUSY, fsconfig(fsfd, FSCONFIG_SET_STRING, "pidns", "/tmp/dummy/pidns", 0));	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0)); /* noop */ 	ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));	ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0)); 	ASSERT_SUCCESS(close(fsfd));	ASSERT_SUCCESS(close(mountfd));} TEST_F(ns, pidns_reconfigure_fsconfig_fd){	int fsfd = fsopen("proc", FSOPEN_CLOEXEC);	ASSERT_SUCCESS(fsfd); 	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0)); 	int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);	ASSERT_SUCCESS(mountfd); 	ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));	ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0)); 	ASSERT_ERRNO_EQ(-EBUSY, fsconfig(fsfd, FSCONFIG_SET_FD, "pidns", NULL, self->dummy_pidns));	ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0)); /* noop */ 	ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));	ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0)); 	ASSERT_SUCCESS(close(fsfd));	ASSERT_SUCCESS(close(mountfd));} TEST_HARNESS_MAIN