priv_sysctl_write.c revision 162271 
1/*-
2 * Copyright (c) 2006 nCircle Network Security, Inc.
3 * All rights reserved.
4 *
5 * This software was developed by Robert N. M. Watson for the TrustedBSD
6 * Project under contract to nCircle Network Security, Inc.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR, NCIRCLE NETWORK SECURITY,
21 * INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
23 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
24 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
25 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
26 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: head/tools/regression/priv/priv_sysctl_write.c 162271 2006-09-13 09:05:39Z rwatson $
30 */
31
32/*
33 * Test that sysctls can only be written with privilege by trying first with,
34 * then without privilege.  Do this by first reading, then setting the
35 * hostname as a no-op.
36 */
37
38#include <sys/types.h>
39#include <sys/sysctl.h>
40
41#include <err.h>
42#include <errno.h>
43#include <string.h>
44#include <unistd.h>
45
46#include "main.h"
47
48#define KERN_HOSTNAME_STRING	"kern.hostname"
49
50void
51priv_sysctl_write(void)
52{
53	char buffer[1024];
54	size_t len;
55	int error;
56
57	assert_root();
58
59	/*
60	 * First query the current value.
61	 */
62	len = sizeof(buffer);
63	error = sysctlbyname(KERN_HOSTNAME_STRING, buffer, &len, NULL, 0);
64	if (error)
65		err(-1, "sysctlbyname(\"%s\") query", KERN_HOSTNAME_STRING);
66
67	/*
68	 * Now try to set with privilege.
69	 */
70	error = sysctlbyname(KERN_HOSTNAME_STRING, NULL, NULL, buffer,
71	    strlen(buffer));
72	if (error)
73		err(-1, "sysctlbyname(\"%s\") set as root",
74		    KERN_HOSTNAME_STRING);
75
76	/*
77	 * Now without privilege.
78	 */
79	set_euid(UID_OTHER);
80
81	error = sysctlbyname(KERN_HOSTNAME_STRING, NULL, NULL, buffer,
82	    strlen(buffer));
83	if (error == 0)
84		errx(-1, "sysctlbyname(\"%s\") succeeded as !root",
85		    KERN_HOSTNAME_STRING);
86	if (errno != EPERM)
87		err(-1, "sysctlbyname(\"%s\") wrong errno %d",
88		    KERN_HOSTNAME_STRING, errno);
89}
90