1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) Wipro Technologies Ltd, 2002. All Rights Reserved.
4 * AUTHOR: Madhu T L <madhu.tarikere@wipro.com>
5 * Copyright (C) 2021 SUSE LLC <mdoucha@suse.cz>
6 */
7
8 /*\
9 * [Description]
10 *
11 * Verify that setresgid() fails with EPERM if unprivileged user tries to set
12 * process group ID which requires higher permissions.
13 */
14
15 #include <sys/types.h>
16 #include <pwd.h>
17
18 #include "tst_test.h"
19 #include "tst_uid.h"
20 #include "compat_tst_16.h"
21
22 struct test_case_t {
23 gid_t *rgid;
24 gid_t *egid;
25 gid_t *sgid;
26 gid_t *exp_rgid;
27 gid_t *exp_egid;
28 gid_t *exp_sgid;
29 char *desc;
30 };
31
32 static gid_t nobody_gid, other_gid, neg = -1;
33
34 static struct test_case_t test_cases[] = {
35 {&neg, &neg, &other_gid, &nobody_gid, &nobody_gid, &nobody_gid,
36 "setresgid(-1, -1, other)"},
37 {&neg, &other_gid, &neg, &nobody_gid, &nobody_gid, &nobody_gid,
38 "setresgid(-1, other, -1)"},
39 {&other_gid, &neg, &neg, &nobody_gid, &nobody_gid, &nobody_gid,
40 "setresgid(other, -1, -1)"},
41 {&other_gid, &other_gid, &other_gid, &nobody_gid, &nobody_gid,
42 &nobody_gid, "setresgid(other, other, other)"},
43 };
44
setup(void)45 static void setup(void)
46 {
47 gid_t test_groups[2];
48 struct passwd *pw = SAFE_GETPWNAM("nobody");
49
50 nobody_gid = test_groups[0] = pw->pw_gid;
51 tst_get_gids(test_groups, 1, 2);
52 other_gid = test_groups[1];
53
54 GID16_CHECK(nobody_gid, setresgid);
55 GID16_CHECK(other_gid, setresgid);
56
57 /* Set real/effective/saved gid to nobody */
58 SAFE_SETRESGID(nobody_gid, nobody_gid, nobody_gid);
59 SAFE_SETUID(pw->pw_uid);
60 }
61
run(unsigned int n)62 static void run(unsigned int n)
63 {
64 const struct test_case_t *tc = test_cases + n;
65
66 TST_EXP_FAIL(SETRESGID(*tc->rgid, *tc->egid, *tc->sgid), EPERM, "%s",
67 tc->desc);
68
69 if (!TST_PASS)
70 return;
71
72 tst_check_resgid(tc->desc, *tc->exp_rgid, *tc->exp_egid,
73 *tc->exp_sgid);
74 }
75
76 static struct tst_test test = {
77 .test = run,
78 .tcnt = ARRAY_SIZE(test_cases),
79 .setup = setup,
80 .needs_root = 1,
81 };
82