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
31 /*
32 * Confirm that a generation number isn't returned by stat() when not running
33 * with privilege. In order to differentiate between a generation of 0 and
34 * a generation not being returned, we have to create a temporary file known
35 * to have a non-0 generation. We try up to MAX_TRIES times, and then give
36 * up, which is non-ideal, but better than not testing for a problem.
37 */
38
39 #include <sys/stat.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 static char fpath[1024];
49 static int fpath_initialized;
50
51 #define MAX_TRIES 100
52
53 int
priv_vfs_generation_setup(int asroot,int injail,struct test * test)54 priv_vfs_generation_setup(int asroot, int injail, struct test *test)
55 {
56 struct stat sb;
57 int i;
58
59 /*
60 * The kernel zeros the generation number field when an unprivileged
61 * user stats a file. In order to distinguish the two cases, we
62 * therefore require a file that we know has a non-zero generation
63 * number. We try up to MAX_TRIES times and otherwise fail.
64 */
65 for (i = 0; i < MAX_TRIES; i++) {
66 setup_file("priv_vfs_generation_setup: fpath", fpath,
67 UID_ROOT, GID_WHEEL, 0644);
68 if (stat(fpath, &sb) < 0) {
69 warn("priv_vfs_generation_setup: fstat(%s)", fpath);
70 (void)unlink(fpath);
71 return (-1);
72 }
73 if (sb.st_gen != 0) {
74 fpath_initialized = 1;
75 return (0);
76 }
77 }
78 warnx("priv_vfs_generation_setup: unable to create gen file");
79 return (-1);
80 }
81
82 void
priv_vfs_generation(int asroot,int injail,struct test * test)83 priv_vfs_generation(int asroot, int injail, struct test *test)
84 {
85 struct stat sb;
86 int error;
87
88 error = stat(fpath, &sb);
89 if (error < 0)
90 warn("priv_vfs_generation(asroot, injail) stat");
91
92 if (sb.st_gen == 0) {
93 error = -1;
94 errno = EPERM;
95 } else
96 error = 0;
97 if (asroot && injail)
98 expect("priv_vfs_generation(asroot, injail)", error, -1,
99 EPERM);
100 if (asroot && !injail)
101 expect("priv_vfs_generation(asroot, !injail)", error, 0, 0);
102 if (!asroot && injail)
103 expect("priv_vfs_generation(!asroot, injail)", error, -1,
104 EPERM);
105 if (!asroot && !injail)
106 expect("priv_vfs_generation(!asroot, !injail)", error, -1,
107 EPERM);
108 }
109
110 void
priv_vfs_generation_cleanup(int asroot,int injail,struct test * test)111 priv_vfs_generation_cleanup(int asroot, int injail, struct test *test)
112 {
113
114 if (fpath_initialized) {
115 (void)unlink(fpath);
116 fpath_initialized = 0;
117 }
118 }
119