1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
|
// 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 <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
|
