1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2001
4 * Author: Wayne Boyer
5 *
6 * Test Description:
7 * Verify that, fchmod(2) will succeed to change the mode of a directory
8 * but fails to set the setgid bit on it if invoked by non-root (uid != 0)
9 * process with the following constraints,
10 * - the process is the owner of the directory.
11 * - the effective group ID or one of the supplementary group ID's of the
12 * process is not equal to the group ID of the directory.
13 *
14 * Expected Result:
15 * fchmod() should return value 0 on success and though succeeds to change
16 * the mode of a directory but fails to set setgid bit on it.
17 */
18
19 #include <pwd.h>
20 #include <errno.h>
21
22 #include "tst_test.h"
23 #include "fchmod.h"
24
25 #define PERMS_DIR 043777
26
27 static int fd;
28
verify_fchmod(void)29 static void verify_fchmod(void)
30 {
31 struct stat stat_buf;
32 mode_t dir_mode;
33
34 TEST(fchmod(fd, PERMS_DIR));
35 if (TST_RET == -1)
36 tst_res(TFAIL | TTERRNO, "fchmod() failed unexpectly");
37
38 SAFE_FSTAT(fd, &stat_buf);
39 dir_mode = stat_buf.st_mode;
40
41 if ((PERMS_DIR & ~S_ISGID) != dir_mode) {
42 tst_res(TFAIL, "%s: Incorrect modes 0%03o, Expected 0%03o",
43 TESTDIR, dir_mode & ~S_ISGID, PERMS_DIR);
44 } else {
45 tst_res(TPASS, "Functionality of fchmod(%d, %#o) successful",
46 fd, PERMS_DIR);
47 }
48 }
49
setup(void)50 static void setup(void)
51 {
52 struct passwd *ltpuser;
53 struct group *ltpgroup;
54
55 ltpuser = SAFE_GETPWNAM("nobody");
56 ltpgroup = SAFE_GETGRNAM("bin");
57
58 SAFE_MKDIR(TESTDIR, DIR_MODE);
59
60 if (setgroups(1, <puser->pw_gid) == -1) {
61 tst_brk(TBROK, "Couldn't change supplementary group Id: %s",
62 tst_strerrno(TST_ERR));
63 }
64
65 SAFE_CHOWN(TESTDIR, ltpuser->pw_uid, ltpgroup->gr_gid);
66
67 SAFE_SETEGID(ltpuser->pw_gid);
68 SAFE_SETEUID(ltpuser->pw_uid);
69
70 fd = SAFE_OPEN(TESTDIR, O_RDONLY);
71 }
72
cleanup(void)73 static void cleanup(void)
74 {
75 if (fd > 0)
76 SAFE_CLOSE(fd);
77
78 SAFE_SETEGID(0);
79 SAFE_SETEUID(0);
80 }
81
82 static struct tst_test test = {
83 .test_all = verify_fchmod,
84 .needs_root = 1,
85 .setup = setup,
86 .cleanup = cleanup,
87 .needs_tmpdir = 1,
88 };
89