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
60char *TCID = "user_namespace3";
61int TST_TOTAL = 1;
62static int cpid1, parentuid, parentgid;
63
64/*
65 * child_fn1() - Inside a new user namespace
66 */
67static 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 */
76static 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
149static void cleanup(void)
150{
151	tst_rmdir();
152}
153
154static void setup(void)
155{
156	check_newuser();
157	tst_tmpdir();
158	TST_CHECKPOINT_INIT(NULL);
159}
160
161int 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