1/*
2 * Copyright (c) 2001 Proofpoint, Inc. and its suppliers.
3 *	All rights reserved.
4 *
5 * By using this file, you agree to the terms and conditions set
6 * forth in the LICENSE file which can be found at the top level of
7 * the sendmail distribution.
8 *
9 */
10
11/*
12**  This program checks to see if your version of setgid works.
13**  Compile it, make it set-group-ID guest, and run it as yourself (NOT as
14**  root and not as member of the group guest).
15**
16**  Compilation is trivial -- just "cc t_setgid.c".  Make it set-group-ID,
17**  guest and then execute it as a non-root user.
18*/
19
20#include <sys/types.h>
21#include <unistd.h>
22#include <stdio.h>
23
24#ifndef lint
25static char id[] = "@(#)$Id: t_setgid.c,v 1.7 2013-11-22 20:52:01 ca Exp $";
26#endif /* ! lint */
27
28static void
29printgids(str, r, e)
30	char *str;
31	gid_t r, e;
32{
33	printf("%s (should be %d/%d): r/egid=%d/%d\n", str, (int) r, (int) e,
34	       (int) getgid(), (int) getegid());
35}
36
37int
38main(argc, argv)
39	int argc;
40	char **argv;
41{
42	int fail = 0;
43	int res;
44	gid_t realgid = getgid();
45	gid_t effgid = getegid();
46
47	printgids("initial gids", realgid, effgid);
48
49	if (effgid == realgid)
50	{
51		printf("SETUP ERROR: re-run set-group-ID guest\n");
52		exit(1);
53	}
54
55#if SM_CONF_SETREGID
56	res = setregid(effgid, effgid);
57#else /* SM_CONF_SETREGID */
58	res = setgid(effgid);
59#endif /* SM_CONF_SETREGID */
60
61	printf("setgid(%d)=%d %s\n", (int) effgid, res,
62		res < 0 ? "failure" : "ok");
63#if SM_CONF_SETREGID
64	printgids("after setregid()", effgid, effgid);
65#else /* SM_CONF_SETREGID */
66	printgids("after setgid()", effgid, effgid);
67#endif /* SM_CONF_SETREGID */
68
69	if (getegid() != effgid)
70	{
71		fail++;
72		printf("MAYDAY!  Wrong effective gid\n");
73	}
74
75	if (getgid() != effgid)
76	{
77		fail++;
78		printf("MAYDAY!  Wrong real gid\n");
79	}
80
81	/* do activity here */
82	if (setgid(0) == 0)
83	{
84		fail++;
85		printf("MAYDAY!  setgid(0) succeeded (should have failed)\n");
86	}
87	else
88	{
89		printf("setgid(0) failed (this is correct)\n");
90	}
91	printgids("after setgid(0)", effgid, effgid);
92
93	if (getegid() != effgid)
94	{
95		fail++;
96		printf("MAYDAY!  Wrong effective gid\n");
97	}
98	if (getgid() != effgid)
99	{
100		fail++;
101		printf("MAYDAY!  Wrong real gid\n");
102	}
103	printf("\n");
104
105	if (fail > 0)
106	{
107		printf("\nThis system cannot use %s to set the real gid to the effective gid\nand clear the saved gid.\n",
108#if SM_CONF_SETREGID
109			"setregid"
110#else /* SM_CONF_SETREGID */
111			"setgid"
112#endif /* SM_CONF_SETREGID */
113			);
114		exit(1);
115	}
116
117	printf("\nIt is possible to use setgid on this system\n");
118	exit(0);
119}
120