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-rw-r--r--tools/testing/selftests/Makefile1
-rw-r--r--tools/testing/selftests/mount/Makefile17
-rw-r--r--tools/testing/selftests/mount/unprivileged-remount-test.c242
3 files changed, 260 insertions, 0 deletions
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 6fd2a4402069..36ff2e4c7b6f 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -5,6 +5,7 @@ TARGETS += kcmp
5TARGETS += memfd 5TARGETS += memfd
6TARGETS += memory-hotplug 6TARGETS += memory-hotplug
7TARGETS += mqueue 7TARGETS += mqueue
8TARGETS += mount
8TARGETS += net 9TARGETS += net
9TARGETS += ptrace 10TARGETS += ptrace
10TARGETS += timers 11TARGETS += timers
diff --git a/tools/testing/selftests/mount/Makefile b/tools/testing/selftests/mount/Makefile
new file mode 100644
index 000000000000..337d853c2b72
--- /dev/null
+++ b/tools/testing/selftests/mount/Makefile
@@ -0,0 +1,17 @@
1# Makefile for mount selftests.
2
3all: unprivileged-remount-test
4
5unprivileged-remount-test: unprivileged-remount-test.c
6 gcc -Wall -O2 unprivileged-remount-test.c -o unprivileged-remount-test
7
8# Allow specific tests to be selected.
9test_unprivileged_remount: unprivileged-remount-test
10 @if [ -f /proc/self/uid_map ] ; then ./unprivileged-remount-test ; fi
11
12run_tests: all test_unprivileged_remount
13
14clean:
15 rm -f unprivileged-remount-test
16
17.PHONY: all test_unprivileged_remount
diff --git a/tools/testing/selftests/mount/unprivileged-remount-test.c b/tools/testing/selftests/mount/unprivileged-remount-test.c
new file mode 100644
index 000000000000..1b3ff2fda4d0
--- /dev/null
+++ b/tools/testing/selftests/mount/unprivileged-remount-test.c
@@ -0,0 +1,242 @@
1#define _GNU_SOURCE
2#include <sched.h>
3#include <stdio.h>
4#include <errno.h>
5#include <string.h>
6#include <sys/types.h>
7#include <sys/mount.h>
8#include <sys/wait.h>
9#include <stdlib.h>
10#include <unistd.h>
11#include <fcntl.h>
12#include <grp.h>
13#include <stdbool.h>
14#include <stdarg.h>
15
16#ifndef CLONE_NEWNS
17# define CLONE_NEWNS 0x00020000
18#endif
19#ifndef CLONE_NEWUTS
20# define CLONE_NEWUTS 0x04000000
21#endif
22#ifndef CLONE_NEWIPC
23# define CLONE_NEWIPC 0x08000000
24#endif
25#ifndef CLONE_NEWNET
26# define CLONE_NEWNET 0x40000000
27#endif
28#ifndef CLONE_NEWUSER
29# define CLONE_NEWUSER 0x10000000
30#endif
31#ifndef CLONE_NEWPID
32# define CLONE_NEWPID 0x20000000
33#endif
34
35#ifndef MS_RELATIME
36#define MS_RELATIME (1 << 21)
37#endif
38#ifndef MS_STRICTATIME
39#define MS_STRICTATIME (1 << 24)
40#endif
41
42static void die(char *fmt, ...)
43{
44 va_list ap;
45 va_start(ap, fmt);
46 vfprintf(stderr, fmt, ap);
47 va_end(ap);
48 exit(EXIT_FAILURE);
49}
50
51static void write_file(char *filename, char *fmt, ...)
52{
53 char buf[4096];
54 int fd;
55 ssize_t written;
56 int buf_len;
57 va_list ap;
58
59 va_start(ap, fmt);
60 buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
61 va_end(ap);
62 if (buf_len < 0) {
63 die("vsnprintf failed: %s\n",
64 strerror(errno));
65 }
66 if (buf_len >= sizeof(buf)) {
67 die("vsnprintf output truncated\n");
68 }
69
70 fd = open(filename, O_WRONLY);
71 if (fd < 0) {
72 die("open of %s failed: %s\n",
73 filename, strerror(errno));
74 }
75 written = write(fd, buf, buf_len);
76 if (written != buf_len) {
77 if (written >= 0) {
78 die("short write to %s\n", filename);
79 } else {
80 die("write to %s failed: %s\n",
81 filename, strerror(errno));
82 }
83 }
84 if (close(fd) != 0) {
85 die("close of %s failed: %s\n",
86 filename, strerror(errno));
87 }
88}
89
90static void create_and_enter_userns(void)
91{
92 uid_t uid;
93 gid_t gid;
94
95 uid = getuid();
96 gid = getgid();
97
98 if (unshare(CLONE_NEWUSER) !=0) {
99 die("unshare(CLONE_NEWUSER) failed: %s\n",
100 strerror(errno));
101 }
102
103 write_file("/proc/self/uid_map", "0 %d 1", uid);
104 write_file("/proc/self/gid_map", "0 %d 1", gid);
105
106 if (setgroups(0, NULL) != 0) {
107 die("setgroups failed: %s\n",
108 strerror(errno));
109 }
110 if (setgid(0) != 0) {
111 die ("setgid(0) failed %s\n",
112 strerror(errno));
113 }
114 if (setuid(0) != 0) {
115 die("setuid(0) failed %s\n",
116 strerror(errno));
117 }
118}
119
120static
121bool test_unpriv_remount(int mount_flags, int remount_flags, int invalid_flags)
122{
123 pid_t child;
124
125 child = fork();
126 if (child == -1) {
127 die("fork failed: %s\n",
128 strerror(errno));
129 }
130 if (child != 0) { /* parent */
131 pid_t pid;
132 int status;
133 pid = waitpid(child, &status, 0);
134 if (pid == -1) {
135 die("waitpid failed: %s\n",
136 strerror(errno));
137 }
138 if (pid != child) {
139 die("waited for %d got %d\n",
140 child, pid);
141 }
142 if (!WIFEXITED(status)) {
143 die("child did not terminate cleanly\n");
144 }
145 return WEXITSTATUS(status) == EXIT_SUCCESS ? true : false;
146 }
147
148 create_and_enter_userns();
149 if (unshare(CLONE_NEWNS) != 0) {
150 die("unshare(CLONE_NEWNS) failed: %s\n",
151 strerror(errno));
152 }
153
154 if (mount("testing", "/tmp", "ramfs", mount_flags, NULL) != 0) {
155 die("mount of /tmp failed: %s\n",
156 strerror(errno));
157 }
158
159 create_and_enter_userns();
160
161 if (unshare(CLONE_NEWNS) != 0) {
162 die("unshare(CLONE_NEWNS) failed: %s\n",
163 strerror(errno));
164 }
165
166 if (mount("/tmp", "/tmp", "none",
167 MS_REMOUNT | MS_BIND | remount_flags, NULL) != 0) {
168 /* system("cat /proc/self/mounts"); */
169 die("remount of /tmp failed: %s\n",
170 strerror(errno));
171 }
172
173 if (mount("/tmp", "/tmp", "none",
174 MS_REMOUNT | MS_BIND | invalid_flags, NULL) == 0) {
175 /* system("cat /proc/self/mounts"); */
176 die("remount of /tmp with invalid flags "
177 "succeeded unexpectedly\n");
178 }
179 exit(EXIT_SUCCESS);
180}
181
182static bool test_unpriv_remount_simple(int mount_flags)
183{
184 return test_unpriv_remount(mount_flags, mount_flags, 0);
185}
186
187static bool test_unpriv_remount_atime(int mount_flags, int invalid_flags)
188{
189 return test_unpriv_remount(mount_flags, mount_flags, invalid_flags);
190}
191
192int main(int argc, char **argv)
193{
194 if (!test_unpriv_remount_simple(MS_RDONLY|MS_NODEV)) {
195 die("MS_RDONLY malfunctions\n");
196 }
197 if (!test_unpriv_remount_simple(MS_NODEV)) {
198 die("MS_NODEV malfunctions\n");
199 }
200 if (!test_unpriv_remount_simple(MS_NOSUID|MS_NODEV)) {
201 die("MS_NOSUID malfunctions\n");
202 }
203 if (!test_unpriv_remount_simple(MS_NOEXEC|MS_NODEV)) {
204 die("MS_NOEXEC malfunctions\n");
205 }
206 if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODEV,
207 MS_NOATIME|MS_NODEV))
208 {
209 die("MS_RELATIME malfunctions\n");
210 }
211 if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODEV,
212 MS_NOATIME|MS_NODEV))
213 {
214 die("MS_STRICTATIME malfunctions\n");
215 }
216 if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODEV,
217 MS_STRICTATIME|MS_NODEV))
218 {
219 die("MS_RELATIME malfunctions\n");
220 }
221 if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODIRATIME|MS_NODEV,
222 MS_NOATIME|MS_NODEV))
223 {
224 die("MS_RELATIME malfunctions\n");
225 }
226 if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODIRATIME|MS_NODEV,
227 MS_NOATIME|MS_NODEV))
228 {
229 die("MS_RELATIME malfunctions\n");
230 }
231 if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODIRATIME|MS_NODEV,
232 MS_STRICTATIME|MS_NODEV))
233 {
234 die("MS_RELATIME malfunctions\n");
235 }
236 if (!test_unpriv_remount(MS_STRICTATIME|MS_NODEV, MS_NODEV,
237 MS_NOATIME|MS_NODEV))
238 {
239 die("Default atime malfunctions\n");
240 }
241 return EXIT_SUCCESS;
242}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-27 04:31:17 -0500