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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Author: Aleksa Sarai <[email protected]>
4 * Copyright (C) 2025 SUSE LLC.
5 */
6
7#include <assert.h>
8#include <errno.h>
9#include <fcntl.h>
10#include <sched.h>
11#include <stdbool.h>
12#include <stdlib.h>
13#include <string.h>
14#include <unistd.h>
15#include <stdio.h>
16#include <sys/mount.h>
17#include <sys/stat.h>
18#include <sys/prctl.h>
19
20#include "kselftest_harness.h"
21
22#define ASSERT_ERRNO(expected, _t, seen) \
23 __EXPECT(expected, #expected, \
24 ({__typeof__(seen) _tmp_seen = (seen); \
25 _tmp_seen >= 0 ? _tmp_seen : -errno; }), #seen, _t, 1)
26
27#define ASSERT_ERRNO_EQ(expected, seen) \
28 ASSERT_ERRNO(expected, ==, seen)
29
30#define ASSERT_SUCCESS(seen) \
31 ASSERT_ERRNO(0, <=, seen)
32
33static int touch(char *path)
34{
35 int fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC, 0644);
36 if (fd < 0)
37 return -1;
38 return close(fd);
39}
40
41FIXTURE(ns)
42{
43 int host_mntns, host_pidns;
44 int dummy_pidns;
45};
46
47FIXTURE_SETUP(ns)
48{
49 /* Stash the old mntns. */
50 self->host_mntns = open("/proc/self/ns/mnt", O_RDONLY|O_CLOEXEC);
51 ASSERT_SUCCESS(self->host_mntns);
52
53 /* Create a new mount namespace and make it private. */
54 ASSERT_SUCCESS(unshare(CLONE_NEWNS));
55 ASSERT_SUCCESS(mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL));
56
57 /*
58 * Create a proper tmpfs that we can use and will disappear once we
59 * leave this mntns.
60 */
61 ASSERT_SUCCESS(mount("tmpfs", "/tmp", "tmpfs", 0, NULL));
62
63 /*
64 * Create a pidns we can use for later tests. We need to fork off a
65 * child so that we get a usable nsfd that we can bind-mount and open.
66 */
67 ASSERT_SUCCESS(mkdir("/tmp/dummy", 0755));
68 ASSERT_SUCCESS(touch("/tmp/dummy/pidns"));
69 ASSERT_SUCCESS(mkdir("/tmp/dummy/proc", 0755));
70
71 self->host_pidns = open("/proc/self/ns/pid", O_RDONLY|O_CLOEXEC);
72 ASSERT_SUCCESS(self->host_pidns);
73 ASSERT_SUCCESS(unshare(CLONE_NEWPID));
74
75 pid_t pid = fork();
76 ASSERT_SUCCESS(pid);
77 if (!pid) {
78 prctl(PR_SET_PDEATHSIG, SIGKILL);
79 ASSERT_SUCCESS(mount("/proc/self/ns/pid", "/tmp/dummy/pidns", NULL, MS_BIND, NULL));
80 ASSERT_SUCCESS(mount("proc", "/tmp/dummy/proc", "proc", 0, NULL));
81 exit(0);
82 }
83
84 int wstatus;
85 ASSERT_EQ(waitpid(pid, &wstatus, 0), pid);
86 ASSERT_TRUE(WIFEXITED(wstatus));
87 ASSERT_EQ(WEXITSTATUS(wstatus), 0);
88
89 ASSERT_SUCCESS(setns(self->host_pidns, CLONE_NEWPID));
90
91 self->dummy_pidns = open("/tmp/dummy/pidns", O_RDONLY|O_CLOEXEC);
92 ASSERT_SUCCESS(self->dummy_pidns);
93}
94
95FIXTURE_TEARDOWN(ns)
96{
97 ASSERT_SUCCESS(setns(self->host_mntns, CLONE_NEWNS));
98 ASSERT_SUCCESS(close(self->host_mntns));
99
100 ASSERT_SUCCESS(close(self->host_pidns));
101 ASSERT_SUCCESS(close(self->dummy_pidns));
102}
103
104TEST_F(ns, pidns_mount_string_path)
105{
106 ASSERT_SUCCESS(mkdir("/tmp/proc-host", 0755));
107 ASSERT_SUCCESS(mount("proc", "/tmp/proc-host", "proc", 0, "pidns=/proc/self/ns/pid"));
108 ASSERT_SUCCESS(access("/tmp/proc-host/self/", X_OK));
109
110 ASSERT_SUCCESS(mkdir("/tmp/proc-dummy", 0755));
111 ASSERT_SUCCESS(mount("proc", "/tmp/proc-dummy", "proc", 0, "pidns=/tmp/dummy/pidns"));
112 ASSERT_ERRNO_EQ(-ENOENT, access("/tmp/proc-dummy/1/", X_OK));
113 ASSERT_ERRNO_EQ(-ENOENT, access("/tmp/proc-dummy/self/", X_OK));
114}
115
116TEST_F(ns, pidns_fsconfig_string_path)
117{
118 int fsfd = fsopen("proc", FSOPEN_CLOEXEC);
119 ASSERT_SUCCESS(fsfd);
120
121 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_SET_STRING, "pidns", "/tmp/dummy/pidns", 0));
122 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
123
124 int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);
125 ASSERT_SUCCESS(mountfd);
126
127 ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "1/", X_OK, 0));
128 ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "self/", X_OK, 0));
129
130 ASSERT_SUCCESS(close(fsfd));
131 ASSERT_SUCCESS(close(mountfd));
132}
133
134TEST_F(ns, pidns_fsconfig_fd)
135{
136 int fsfd = fsopen("proc", FSOPEN_CLOEXEC);
137 ASSERT_SUCCESS(fsfd);
138
139 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_SET_FD, "pidns", NULL, self->dummy_pidns));
140 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
141
142 int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);
143 ASSERT_SUCCESS(mountfd);
144
145 ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "1/", X_OK, 0));
146 ASSERT_ERRNO_EQ(-ENOENT, faccessat(mountfd, "self/", X_OK, 0));
147
148 ASSERT_SUCCESS(close(fsfd));
149 ASSERT_SUCCESS(close(mountfd));
150}
151
152TEST_F(ns, pidns_reconfigure_remount)
153{
154 ASSERT_SUCCESS(mkdir("/tmp/proc", 0755));
155 ASSERT_SUCCESS(mount("proc", "/tmp/proc", "proc", 0, ""));
156
157 ASSERT_SUCCESS(access("/tmp/proc/1/", X_OK));
158 ASSERT_SUCCESS(access("/tmp/proc/self/", X_OK));
159
160 ASSERT_ERRNO_EQ(-EBUSY, mount(NULL, "/tmp/proc", NULL, MS_REMOUNT, "pidns=/tmp/dummy/pidns"));
161
162 ASSERT_SUCCESS(access("/tmp/proc/1/", X_OK));
163 ASSERT_SUCCESS(access("/tmp/proc/self/", X_OK));
164}
165
166TEST_F(ns, pidns_reconfigure_fsconfig_string_path)
167{
168 int fsfd = fsopen("proc", FSOPEN_CLOEXEC);
169 ASSERT_SUCCESS(fsfd);
170
171 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
172
173 int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);
174 ASSERT_SUCCESS(mountfd);
175
176 ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));
177 ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0));
178
179 ASSERT_ERRNO_EQ(-EBUSY, fsconfig(fsfd, FSCONFIG_SET_STRING, "pidns", "/tmp/dummy/pidns", 0));
180 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0)); /* noop */
181
182 ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));
183 ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0));
184
185 ASSERT_SUCCESS(close(fsfd));
186 ASSERT_SUCCESS(close(mountfd));
187}
188
189TEST_F(ns, pidns_reconfigure_fsconfig_fd)
190{
191 int fsfd = fsopen("proc", FSOPEN_CLOEXEC);
192 ASSERT_SUCCESS(fsfd);
193
194 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0));
195
196 int mountfd = fsmount(fsfd, FSMOUNT_CLOEXEC, 0);
197 ASSERT_SUCCESS(mountfd);
198
199 ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));
200 ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0));
201
202 ASSERT_ERRNO_EQ(-EBUSY, fsconfig(fsfd, FSCONFIG_SET_FD, "pidns", NULL, self->dummy_pidns));
203 ASSERT_SUCCESS(fsconfig(fsfd, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0)); /* noop */
204
205 ASSERT_SUCCESS(faccessat(mountfd, "1/", X_OK, 0));
206 ASSERT_SUCCESS(faccessat(mountfd, "self/", X_OK, 0));
207
208 ASSERT_SUCCESS(close(fsfd));
209 ASSERT_SUCCESS(close(mountfd));
210}
211
212TEST_HARNESS_MAIN