1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) International Business Machines Corp., 2001
4 */
5
6/*
7 * DESCRIPTION
8 *	Check if setuid behaves correctly with file permissions. The test
9 *	creates a file as ROOT with permissions 0644, does a setuid and then
10 *	tries to open the file with RDWR permissions. The same test is done
11 *	in a fork to check if new UIDs are correctly passed to the son.
12 */
13
14#include <errno.h>
15#include <pwd.h>
16#include <unistd.h>
17#include <sys/types.h>
18#include <fcntl.h>
19#include "tst_test.h"
20#include "compat_tst_16.h"
21
22#define  FILENAME  "setuid04_testfile"
23
24static void dosetuid(void);
25
26static void verify_setuid(void)
27{
28	pid_t pid;
29
30	pid = SAFE_FORK();
31	if (!pid)
32		dosetuid();
33	else
34		dosetuid();
35}
36
37static void dosetuid(void)
38{
39	int tst_fd;
40
41	TEST(tst_fd = open(FILENAME, O_RDWR));
42	if (TST_RET != -1) {
43		tst_res(TFAIL, "open() succeeded unexpectedly");
44		close(tst_fd);
45		return;
46	}
47
48	if (TST_ERR == EACCES)
49		tst_res(TPASS, "open() returned errno EACCES");
50	else
51		tst_res(TFAIL | TTERRNO, "open() returned unexpected errno");
52}
53
54static void setup(void)
55{
56	struct passwd *pw;
57	uid_t uid;
58
59	pw = SAFE_GETPWNAM("nobody");
60	uid = pw->pw_uid;
61
62	UID16_CHECK(uid, setuid);
63	/* Create test file */
64	SAFE_TOUCH(FILENAME, 0644, NULL);
65
66	if (SETUID(uid) == -1) {
67		tst_brk(TBROK,
68			"setuid() failed to set the effective uid to %d", uid);
69	}
70}
71
72static struct tst_test test = {
73	.setup = setup,
74	.needs_root = 1,
75	.test_all = verify_setuid,
76	.needs_tmpdir = 1,
77	.forks_child = 1,
78};
79