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
25 static char id[] = "@(#)$Id: t_setgid.c,v 1.7 2013-11-22 20:52:01 ca Exp $";
26 #endif /* ! lint */
27
28 static void
printgids(str,r,e)29 printgids(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
37 int
main(argc,argv)38 main(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