1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) International Business Machines  Corp., 2001
4 *    Ported by John George
5 * Copyright (C) 2021 SUSE LLC <mdoucha@suse.cz>
6 */
7
8/*\
9 * [Description]
10 *
11 * Test the setreuid() feature, verifying the role of the saved-set-uid
12 * and setreuid's effect on it.
13 */
14
15#include <sys/types.h>
16#include <pwd.h>
17#include <stdlib.h>
18
19#include "tst_test.h"
20#include "tst_uid.h"
21#include "compat_tst_16.h"
22
23static uid_t root_uid, nobody_uid, main_uid, other_uid, neg_one = -1;
24
25struct test_data_t {
26	uid_t *real_uid;
27	uid_t *eff_uid;
28	int exp_ret;
29	uid_t *exp_real_uid;
30	uid_t *exp_eff_uid;
31	uid_t *exp_sav_uid;
32	const char *test_msg;
33} test_data[] = {
34	{&nobody_uid, &root_uid, 0, &nobody_uid, &root_uid, &root_uid,
35		"setreuid(nobody, root)"},
36	{&neg_one, &nobody_uid, 0, &nobody_uid, &nobody_uid, &root_uid,
37		"setreuid(-1, nobody)"},
38	{&neg_one, &root_uid, 0, &nobody_uid, &root_uid, &root_uid,
39		"setreuid(-1, root)"},
40	{&main_uid, &neg_one, 0, &main_uid, &root_uid, &root_uid,
41		"setreuid(main, -1)"},
42	{&neg_one, &other_uid, 0, &main_uid, &other_uid, &other_uid,
43		"setreuid(-1, other)"},
44	{&neg_one, &root_uid, -1, &main_uid, &other_uid, &other_uid,
45		"setreuid(-1, root)"},
46	{&neg_one, &nobody_uid, -1, &main_uid, &other_uid, &other_uid,
47		"setreuid(-1, nobody)"},
48	{&neg_one, &main_uid, 0, &main_uid, &main_uid, &other_uid,
49		"setreuid(-1, main)"},
50	{&neg_one, &other_uid, 0, &main_uid, &other_uid, &other_uid,
51		"setreuid(-1, other)"},
52	{&other_uid, &main_uid, 0, &other_uid, &main_uid, &main_uid,
53		"setreuid(other, main)"},
54	{&neg_one, &other_uid, 0, &other_uid, &other_uid, &main_uid,
55		"setreuid(-1, other)"},
56	{&neg_one, &main_uid, 0, &other_uid, &main_uid, &main_uid,
57		"setreuid(-1, main)"},
58	{&main_uid, &neg_one, 0, &main_uid, &main_uid, &main_uid,
59		"setreuid(main, -1)"},
60	{&neg_one, &other_uid, -1, &main_uid, &main_uid, &main_uid,
61		"setreuid(-1, other)"},
62};
63
64static void setup(void)
65{
66	uid_t test_users[3];
67	struct passwd *pw;
68
69	root_uid = getuid();
70	pw = SAFE_GETPWNAM("nobody");
71	nobody_uid = test_users[0] = pw->pw_uid;
72	tst_get_uids(test_users, 1, 3);
73	main_uid = test_users[1];
74	other_uid = test_users[2];
75
76	UID16_CHECK(root_uid, setreuid);
77	UID16_CHECK(nobody_uid, setreuid);
78	UID16_CHECK(main_uid, setreuid);
79	UID16_CHECK(other_uid, setreuid);
80
81	/* Make sure that saved UID is also set to root */
82	SAFE_SETUID(root_uid);
83}
84
85static void run_child(const struct test_data_t *tc)
86{
87	if (tc->exp_ret) {
88		TST_EXP_FAIL(SETREUID(*tc->real_uid, *tc->eff_uid), EPERM,
89			"%s", tc->test_msg);
90	} else {
91		TST_EXP_PASS(SETREUID(*tc->real_uid, *tc->eff_uid), "%s",
92			tc->test_msg);
93	}
94
95	if (!TST_PASS)
96		return;
97
98	tst_check_resuid(tc->test_msg, *tc->exp_real_uid, *tc->exp_eff_uid,
99		*tc->exp_sav_uid);
100}
101
102static void run(void)
103{
104	if (!SAFE_FORK()) {
105		unsigned int i;
106
107		for (i = 0; i < ARRAY_SIZE(test_data); i++)
108			run_child(test_data + i);
109
110		exit(0);
111	}
112
113	tst_reap_children();
114}
115
116static struct tst_test test = {
117	.test_all = run,
118	.setup = setup,
119	.needs_root = 1,
120	.forks_child = 1,
121};
122