1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) International Business Machines  Corp., 2001
4 * 07/2001 Ported by Wayne Boyer
5 */
6
7/*\
8 * [Description]
9 *
10 * Verify that, chown(2) succeeds to change the group of a file specified
11 * by path when called by non-root user with the following constraints:
12 *
13 * - euid of the process is equal to the owner of the file.
14 * - the intended gid is either egid, or one of the supplementary gids
15 *   of the process.
16 *
17 * Also verify that chown() clears the setuid/setgid bits set on the file.
18 */
19
20#include <pwd.h>
21
22#include "tst_test.h"
23#include "compat_tst_16.h"
24
25#define FILE_MODE (S_IFREG|S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)
26#define NEW_PERMS (S_IFREG|S_IRWXU|S_IRWXG|S_ISUID|S_ISGID)
27#define FILENAME "chown03_testfile"
28
29static struct passwd *ltpuser;
30
31static void check_owner(struct stat *s, uid_t exp_uid, gid_t exp_gid)
32{
33	if (s->st_uid != exp_uid || s->st_gid != exp_gid)
34		tst_res(TFAIL, "%s: wrong owner set to (uid=%d, gid=%d),"
35			       " expected (uid=%d, gid=%d)",
36			FILENAME, s->st_uid, s->st_gid, exp_uid, exp_gid);
37}
38
39static void check_mode(struct stat *s, mode_t exp_mode)
40{
41	if (s->st_mode != exp_mode)
42	      tst_res(TFAIL, "%s: wrong mode permissions %#o, expected %#o",
43		      FILENAME, s->st_mode, exp_mode);
44}
45
46static void run(void)
47{
48	SAFE_SETEUID(0);
49	SAFE_CHOWN(FILENAME, -1, 0);
50	SAFE_CHMOD(FILENAME, NEW_PERMS);
51	SAFE_SETEUID(ltpuser->pw_uid);
52
53	uid_t uid;
54	gid_t gid;
55	UID16_CHECK((uid = geteuid()), "chown");
56	GID16_CHECK((gid = getegid()), "chown");
57
58	struct stat stat_buf;
59	SAFE_STAT(FILENAME, &stat_buf);
60	check_owner(&stat_buf, uid, 0);
61	check_mode(&stat_buf, NEW_PERMS);
62
63	TST_EXP_PASS(CHOWN(FILENAME, -1, gid), "chown(%s, %d, %d)",
64		     FILENAME, -1, gid);
65	SAFE_STAT(FILENAME, &stat_buf);
66	check_owner(&stat_buf, uid, gid);
67	check_mode(&stat_buf, NEW_PERMS & ~(S_ISUID | S_ISGID));
68}
69
70static void setup(void)
71{
72	int fd;
73
74	ltpuser = SAFE_GETPWNAM("nobody");
75	SAFE_SETEGID(ltpuser->pw_gid);
76	SAFE_SETEUID(ltpuser->pw_uid);
77
78	fd = SAFE_OPEN(FILENAME, O_RDWR | O_CREAT, FILE_MODE);
79	SAFE_CLOSE(fd);
80}
81
82static void cleanup(void)
83{
84	SAFE_SETEGID(0);
85	SAFE_SETEUID(0);
86}
87
88static struct tst_test test = {
89	.needs_root = 1,
90	.needs_tmpdir = 1,
91	.setup = setup,
92	.cleanup = cleanup,
93	.test_all = run,
94};
95