priv_vfs_generation.c revision 303975 
1/*-
2 * Copyright (c) 2006 nCircle Network Security, Inc.
3 * Copyright (c) 2007 Robert N. M. Watson
4 * All rights reserved.
5 *
6 * This software was developed by Robert N. M. Watson for the TrustedBSD
7 * Project under contract to nCircle Network Security, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR, NCIRCLE NETWORK SECURITY,
22 * INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
24 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
25 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * $FreeBSD: releng/11.0/tools/regression/priv/priv_vfs_generation.c 172106 2007-09-09 23:08:39Z rwatson $
31 */
32
33/*
34 * Confirm that a generation number isn't returned by stat() when not running
35 * with privilege.  In order to differentiate between a generation of 0 and
36 * a generation not being returned, we have to create a temporary file known
37 * to have a non-0 generation.  We try up to MAX_TRIES times, and then give
38 * up, which is non-ideal, but better than not testing for a problem.
39 */
40
41#include <sys/stat.h>
42
43#include <err.h>
44#include <errno.h>
45#include <string.h>
46#include <unistd.h>
47
48#include "main.h"
49
50static char fpath[1024];
51static int fpath_initialized;
52
53#define	MAX_TRIES	100
54
55int
56priv_vfs_generation_setup(int asroot, int injail, struct test *test)
57{
58	struct stat sb;
59	int i;
60
61	/*
62	 * The kernel zeros the generation number field when an unprivileged
63	 * user stats a file.  In order to distinguish the two cases, we
64	 * therefore require a file that we know has a non-zero generation
65	 * number.  We try up to MAX_TRIES times and otherwise fail.
66	 */
67	for (i = 0; i < MAX_TRIES; i++) {
68		setup_file("priv_vfs_generation_setup: fpath", fpath,
69		    UID_ROOT, GID_WHEEL, 0644);
70		if (stat(fpath, &sb) < 0) {
71			warn("priv_vfs_generation_setup: fstat(%s)", fpath);
72			(void)unlink(fpath);
73			return (-1);
74		}
75		if (sb.st_gen != 0) {
76			fpath_initialized = 1;
77			return (0);
78		}
79	}
80	warnx("priv_vfs_generation_setup: unable to create gen file");
81	return (-1);
82}
83
84void
85priv_vfs_generation(int asroot, int injail, struct test *test)
86{
87	struct stat sb;
88	int error;
89
90	error = stat(fpath, &sb);
91	if (error < 0)
92		warn("priv_vfs_generation(asroot, injail) stat");
93
94	if (sb.st_gen == 0) {
95		error = -1;
96		errno = EPERM;
97	} else
98		error = 0;
99	if (asroot && injail)
100		expect("priv_vfs_generation(asroot, injail)", error, -1,
101		    EPERM);
102	if (asroot && !injail)
103		expect("priv_vfs_generation(asroot, !injail)", error, 0, 0);
104	if (!asroot && injail)
105		expect("priv_vfs_generation(!asroot, injail)", error, -1,
106		    EPERM);
107	if (!asroot && !injail)
108		expect("priv_vfs_generation(!asroot, !injail)", error, -1,
109		    EPERM);
110}
111
112void
113priv_vfs_generation_cleanup(int asroot, int injail, struct test *test)
114{
115
116	if (fpath_initialized) {
117		(void)unlink(fpath);
118		fpath_initialized = 0;
119	}
120}
121