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
24 static void dosetuid(void);
25
verify_setuid(void)26 static 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
dosetuid(void)37 static 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
setup(void)54 static 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
72 static 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