t_setreuid.c revision 64562 
1/*
2**  This program checks to see if your version of setreuid works.
3**  Compile it, make it setuid root, and run it as yourself (NOT as
4**  root).  If it won't compile or outputs any MAYDAY messages, don't
5**  define HASSETREUID in conf.h.
6**
7**  Compilation is trivial -- just "cc t_setreuid.c".  Make it setuid,
8**  root and then execute it as a non-root user.
9*/
10
11#include <sys/types.h>
12#include <unistd.h>
13#include <stdio.h>
14
15#ifndef lint
16static char id[] = "@(#)$Id: t_setreuid.c,v 8.4 1999/08/28 00:25:28 gshapiro Exp $";
17#endif /* ! lint */
18
19#ifdef __hpux
20# define setreuid(r, e)	setresuid(r, e, -1)
21#endif /* __hpux */
22
23static void
24printuids(str, r, e)
25	char *str;
26	int r, e;
27{
28	printf("%s (should be %d/%d): r/euid=%d/%d\n", str, r, e,
29		getuid(), geteuid());
30}
31
32int
33main(argc, argv)
34	int argc;
35	char **argv;
36{
37	int fail = 0;
38	uid_t realuid = getuid();
39
40	printuids("initial uids", realuid, 0);
41
42	if (geteuid() != 0)
43	{
44		printf("SETUP ERROR: re-run setuid root\n");
45		exit(1);
46	}
47
48	if (getuid() == 0)
49	{
50		printf("SETUP ERROR: must be run by a non-root user\n");
51		exit(1);
52	}
53
54	if (setreuid(0, 1) < 0)
55	{
56		fail++;
57		printf("setreuid(0, 1) failure\n");
58	}
59	printuids("after setreuid(0, 1)", 0, 1);
60
61	if (geteuid() != 1)
62	{
63		fail++;
64		printf("MAYDAY!  Wrong effective uid\n");
65	}
66
67	/* do activity here */
68
69	if (setreuid(-1, 0) < 0)
70	{
71		fail++;
72		printf("setreuid(-1, 0) failure\n");
73	}
74	printuids("after setreuid(-1, 0)", 0, 0);
75	if (setreuid(realuid, 0) < 0)
76	{
77		fail++;
78		printf("setreuid(%d, 0) failure\n", realuid);
79	}
80	printuids("after setreuid(realuid, 0)", realuid, 0);
81
82	if (geteuid() != 0)
83	{
84		fail++;
85		printf("MAYDAY!  Wrong effective uid\n");
86	}
87	if (getuid() != realuid)
88	{
89		fail++;
90		printf("MAYDAY!  Wrong real uid\n");
91	}
92	printf("\n");
93
94	if (setreuid(0, 2) < 0)
95	{
96		fail++;
97		printf("setreuid(0, 2) failure\n");
98	}
99	printuids("after setreuid(0, 2)", 0, 2);
100
101	if (geteuid() != 2)
102	{
103		fail++;
104		printf("MAYDAY!  Wrong effective uid\n");
105	}
106
107	/* do activity here */
108
109	if (setreuid(-1, 0) < 0)
110	{
111		fail++;
112		printf("setreuid(-1, 0) failure\n");
113	}
114	printuids("after setreuid(-1, 0)", 0, 0);
115	if (setreuid(realuid, 0) < 0)
116	{
117		fail++;
118		printf("setreuid(%d, 0) failure\n", realuid);
119	}
120	printuids("after setreuid(realuid, 0)", realuid, 0);
121
122	if (geteuid() != 0)
123	{
124		fail++;
125		printf("MAYDAY!  Wrong effective uid\n");
126	}
127	if (getuid() != realuid)
128	{
129		fail++;
130		printf("MAYDAY!  Wrong real uid\n");
131	}
132
133	if (fail)
134	{
135		printf("\nThis system cannot use setreuid\n");
136		exit(1);
137	}
138
139	printf("\nIt is safe to define HASSETREUID on this system\n");
140	exit(0);
141}
142