1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
/*-
* Copyright (c) 2006 nCircle Network Security, Inc.
* All rights reserved.
*
* This software was developed by Robert N. M. Watson for the TrustedBSD
* Project under contract to nCircle Network Security, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR, NCIRCLE NETWORK SECURITY,
* INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* Confirm that a generation number isn't returned by stat() when not running
* with privilege. In order to differentiate between a generation of 0 and
* a generation not being returned, we have to create a temporary file known
* to have a non-0 generation. We try up to 10 times, and then give up,
* which is non-ideal, but better than not testing for a problem.
*/
#include <sys/stat.h>
#include <err.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include "main.h"
/*
* Can't use setup_file() since the resulting file needs to have specific
* properties.
*/
void
priv_vfs_generation(void)
{
char fpath[1024] = "/tmp/priv.XXXXXXXXXX";
struct stat sb;
int fd, i;
assert_root();
/*
* Create a file with a non-0 generation number. Try ten times,
* which gives a high chance of succeeds, fail otherwise. Not ideal,
* since we can't distinguish the file having a generation of 0 from
* not being able to query it for access control reasons. The perils
* of an API that changes behavior based on lack of privilege rather
* than failing...
*/
for (i = 0; i < 10; i++) {
fd = mkstemp(fpath);
if (fd < 0)
err(-1, "mkstemp");
if (fstat(fd, &sb) < 0) {
warn("fstat(%s)", fpath);
close(fd);
goto out;
}
if (sb.st_gen != 0)
break;
close(fd);
(void)unlink(fpath);
strcpy(fpath, "/tmp/generation.XXXXXXXXXX");
fd = -1;
}
if (fd == -1)
errx(-1,
"could not create file with non-0 generation as root");
close(fd);
/*
* We've already tested that fstat() works, but try stat() to be
* consistent between privileged and unprivileged tests.
*/
if (stat(fpath, &sb) < 0) {
warn("stat(%s) as root", fpath);
goto out;
}
set_euid(UID_OTHER);
if (stat(fpath, &sb) < 0) {
warn("stat(%s) as !root", fpath);
goto out;
}
if (sb.st_gen != 0)
warn("stat(%s) returned generation as !root", fpath);
out:
(void)seteuid(UID_ROOT);
(void)unlink(fpath);
}
|
