1 /*
2 * Copyright (c) Huawei Technologies Co., Ltd., 2015
3 * This program is free software; you can redistribute it and/or modify it
4 * under the terms of the GNU General Public License as published by the Free
5 * Software Foundation; either version 2 of the License, or (at your option)
6 * any later version. This program is distributed in the hope that it will be
7 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
9 * Public License for more details. You should have received a copy of the GNU
10 * General Public License along with this program.
11 */
12
13 /*
14 * Verify that:
15 * /proc/PID/uid_map and /proc/PID/gid_map contains three values separated by
16 * white space:
17 * ID-inside-ns ID-outside-ns length
18 *
19 * ID-outside-ns is interpreted according to which process is opening the file.
20 * If the process opening the file is in the same user namespace as the process
21 * PID, then ID-outside-ns is defined with respect to the parent user namespace.
22 * If the process opening the file is in a different user namespace, then
23 * ID-outside-ns is defined with respect to the user namespace of the process
24 * opening the file.
25 *
26 * The string "deny" would be written to /proc/self/setgroups before GID
27 * check if setgroups is allowed, see kernel commits:
28 *
29 * commit 9cc46516ddf497ea16e8d7cb986ae03a0f6b92f8
30 * Author: Eric W. Biederman <ebiederm@xmission.com>
31 * Date: Tue Dec 2 12:27:26 2014 -0600
32 * userns: Add a knob to disable setgroups on a per user namespace basis
33 *
34 * commit 66d2f338ee4c449396b6f99f5e75cd18eb6df272
35 * Author: Eric W. Biederman <ebiederm@xmission.com>
36 * Date: Fri Dec 5 19:36:04 2014 -0600
37 * userns: Allow setting gid_maps without privilege when setgroups is disabled
38 *
39 */
40
41 #define _GNU_SOURCE
42 #include <sys/wait.h>
43 #include <assert.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <stdbool.h>
47 #include <unistd.h>
48 #include <string.h>
49 #include <errno.h>
50 #include "userns_helper.h"
51 #include "test.h"
52
53 #define CHILD1UID 0
54 #define CHILD1GID 0
55 #define CHILD2UID 200
56 #define CHILD2GID 200
57 #define UID_MAP 0
58 #define GID_MAP 1
59
60 char *TCID = "user_namespace3";
61 int TST_TOTAL = 1;
62 static int cpid1, parentuid, parentgid;
63
64 /*
65 * child_fn1() - Inside a new user namespace
66 */
child_fn1(void)67 static int child_fn1(void)
68 {
69 TST_SAFE_CHECKPOINT_WAIT(NULL, 0);
70 return 0;
71 }
72
73 /*
74 * child_fn2() - Inside a new user namespace
75 */
child_fn2(void)76 static int child_fn2(void)
77 {
78 int exit_val = 0;
79 int uid, gid;
80 char cpid1uidpath[BUFSIZ];
81 char cpid1gidpath[BUFSIZ];
82 int idinsidens, idoutsidens, length;
83
84 TST_SAFE_CHECKPOINT_WAIT(NULL, 1);
85
86 uid = geteuid();
87 gid = getegid();
88
89 if (uid != CHILD2UID || gid != CHILD2GID) {
90 printf("unexpected uid=%d gid=%d\n", uid, gid);
91 exit_val = 1;
92 }
93
94 /*Get the uid parameters of the child_fn2 process.*/
95 SAFE_FILE_SCANF(NULL, "/proc/self/uid_map", "%d %d %d", &idinsidens,
96 &idoutsidens, &length);
97
98 /* map file format:ID-inside-ns ID-outside-ns length
99 If the process opening the file is in the same user namespace as
100 the process PID, then ID-outside-ns is defined with respect to the
101 parent user namespace.*/
102 if (idinsidens != CHILD2UID || idoutsidens != parentuid) {
103 printf("child_fn2 checks /proc/cpid2/uid_map:\n");
104 printf("unexpected: idinsidens=%d idoutsidens=%d\n",
105 idinsidens, idoutsidens);
106 exit_val = 1;
107 }
108
109 sprintf(cpid1uidpath, "/proc/%d/uid_map", cpid1);
110 SAFE_FILE_SCANF(NULL, cpid1uidpath, "%d %d %d", &idinsidens,
111 &idoutsidens, &length);
112
113 /* If the process opening the file is in a different user namespace,
114 then ID-outside-ns is defined with respect to the user namespace
115 of the process opening the file.*/
116 if (idinsidens != CHILD1UID || idoutsidens != CHILD2UID) {
117 printf("child_fn2 checks /proc/cpid1/uid_map:\n");
118 printf("unexpected: idinsidens=%d idoutsidens=%d\n",
119 idinsidens, idoutsidens);
120 exit_val = 1;
121 }
122
123 sprintf(cpid1gidpath, "/proc/%d/gid_map", cpid1);
124 SAFE_FILE_SCANF(NULL, "/proc/self/gid_map", "%d %d %d",
125 &idinsidens, &idoutsidens, &length);
126
127 if (idinsidens != CHILD2GID || idoutsidens != parentgid) {
128 printf("child_fn2 checks /proc/cpid2/gid_map:\n");
129 printf("unexpected: idinsidens=%d idoutsidens=%d\n",
130 idinsidens, idoutsidens);
131 exit_val = 1;
132 }
133
134 SAFE_FILE_SCANF(NULL, cpid1gidpath, "%d %d %d", &idinsidens,
135 &idoutsidens, &length);
136
137 if (idinsidens != CHILD1GID || idoutsidens != CHILD2GID) {
138 printf("child_fn1 checks /proc/cpid1/gid_map:\n");
139 printf("unexpected: idinsidens=%d idoutsidens=%d\n",
140 idinsidens, idoutsidens);
141 exit_val = 1;
142 }
143
144 TST_SAFE_CHECKPOINT_WAKE(NULL, 0);
145 TST_SAFE_CHECKPOINT_WAKE(NULL, 1);
146 return exit_val;
147 }
148
cleanup(void)149 static void cleanup(void)
150 {
151 tst_rmdir();
152 }
153
setup(void)154 static void setup(void)
155 {
156 check_newuser();
157 tst_tmpdir();
158 TST_CHECKPOINT_INIT(NULL);
159 }
160
main(int argc,char * argv[])161 int main(int argc, char *argv[])
162 {
163 pid_t cpid2;
164 char path[BUFSIZ];
165 int lc;
166 int fd;
167 int ret;
168
169 tst_parse_opts(argc, argv, NULL, NULL);
170 setup();
171
172 for (lc = 0; TEST_LOOPING(lc); lc++) {
173 tst_count = 0;
174
175 parentuid = geteuid();
176 parentgid = getegid();
177
178 cpid1 = ltp_clone_quick(CLONE_NEWUSER | SIGCHLD,
179 (void *)child_fn1, NULL);
180 if (cpid1 < 0)
181 tst_brkm(TBROK | TERRNO, cleanup,
182 "cpid1 clone failed");
183
184 cpid2 = ltp_clone_quick(CLONE_NEWUSER | SIGCHLD,
185 (void *)child_fn2, NULL);
186 if (cpid2 < 0)
187 tst_brkm(TBROK | TERRNO, cleanup,
188 "cpid2 clone failed");
189
190 if (access("/proc/self/setgroups", F_OK) == 0) {
191 sprintf(path, "/proc/%d/setgroups", cpid1);
192 fd = SAFE_OPEN(cleanup, path, O_WRONLY, 0644);
193 SAFE_WRITE(cleanup, 1, fd, "deny", 4);
194 SAFE_CLOSE(cleanup, fd);
195 /* If the setgroups file has the value "deny",
196 * then the setgroups(2) system call can't
197 * subsequently be reenabled (by writing "allow" to
198 * the file) in this user namespace. (Attempts to
199 * do so will fail with the error EPERM.)
200 */
201
202 /* test that setgroups can't be re-enabled */
203 fd = SAFE_OPEN(cleanup, path, O_WRONLY, 0644);
204 ret = write(fd, "allow", 5);
205
206 if (ret != -1) {
207 tst_brkm(TBROK | TERRNO, cleanup,
208 "write action should fail");
209 } else if (errno != EPERM) {
210 tst_brkm(TBROK | TERRNO, cleanup,
211 "unexpected error: \n");
212 }
213 SAFE_CLOSE(cleanup, fd);
214 tst_resm(TPASS, "setgroups can't be re-enabled");
215
216 sprintf(path, "/proc/%d/setgroups", cpid2);
217 fd = SAFE_OPEN(cleanup, path, O_WRONLY, 0644);
218 SAFE_WRITE(cleanup, 1, fd, "deny", 4);
219 SAFE_CLOSE(cleanup, fd);
220 }
221
222 updatemap(cpid1, UID_MAP, CHILD1UID, parentuid, cleanup);
223 updatemap(cpid2, UID_MAP, CHILD2UID, parentuid, cleanup);
224
225 updatemap(cpid1, GID_MAP, CHILD1GID, parentgid, cleanup);
226 updatemap(cpid2, GID_MAP, CHILD2GID, parentgid, cleanup);
227
228 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 1);
229
230 tst_record_childstatus(cleanup, cpid1);
231 tst_record_childstatus(cleanup, cpid2);
232 }
233 cleanup();
234 tst_exit();
235 }
236