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
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/*-
* Copyright (c) 2009-2011 Robert N. M. Watson
* Copyright (c) 2011 Jonathan Anderson
* All rights reserved.
*
* 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 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.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/errno.h>
#include <err.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "cap_test.h"
/*
* Test openat(2) in a variety of sitations to ensure that it obeys Capsicum
* "strict relative" rules:
*
* 1. Use strict relative lookups in capability mode or when operating
* relative to a capability.
* 2. When performing strict relative lookups, absolute paths (including
* symlinks to absolute paths) are not allowed, nor are paths containing
* '..' components.
*/
int
test_relative(void)
{
int success = PASSED;
int fd, etc, etc_cap, etc_cap_ro, etc_cap_base, etc_cap_all;
cap_rights_t baserights = CAP_READ | CAP_WRITE | CAP_SEEK | CAP_LOOKUP;
cap_rights_t rights;
REQUIRE(etc = open("/etc/", O_RDONLY));
CHECK_SYSCALL_SUCCEEDS(cap_getrights, etc, &rights);
CHECK_RIGHTS(rights, CAP_ALL);
MAKE_CAPABILITY(etc_cap, etc, CAP_READ);
MAKE_CAPABILITY(etc_cap_ro, etc, CAP_READ | CAP_LOOKUP);
MAKE_CAPABILITY(etc_cap_base, etc, baserights);
MAKE_CAPABILITY(etc_cap_all, etc, CAP_MASK_VALID);
/*
* openat(2) with regular file descriptors in non-capability mode
* should Just Work (tm).
*/
CHECK_SYSCALL_SUCCEEDS(openat, etc, "/etc/passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, AT_FDCWD, "/etc/passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, etc, "passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, etc, "../etc/passwd", O_RDONLY);
/*
* Lookups relative to capabilities should be strictly relative.
*
* When not in capability mode, we don't actually require CAP_LOOKUP.
*/
CHECK_SYSCALL_SUCCEEDS(openat, etc_cap_ro, "passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, etc_cap_base, "passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, etc_cap_all, "passwd", O_RDONLY);
CHECK_NOTCAPABLE(openat, etc_cap_ro, "../etc/passwd", O_RDONLY);
CHECK_NOTCAPABLE(openat, etc_cap_base, "../etc/passwd", O_RDONLY);
/*
* This requires discussion: do we treat a capability with
* CAP_MASK_VALID *exactly* like a non-capability file descriptor
* (currently, the implementation says yes)?
*/
CHECK_SYSCALL_SUCCEEDS(openat, etc_cap_all, "../etc/passwd", O_RDONLY);
/*
* A file opened relative to a capability should itself be a capability.
*/
CHECK_SYSCALL_SUCCEEDS(cap_getrights, etc_cap_base, &rights);
REQUIRE(fd = openat(etc_cap_base, "passwd", O_RDONLY));
CHECK_SYSCALL_SUCCEEDS(cap_getrights, fd, &rights);
CHECK_RIGHTS(rights, baserights);
/*
* Enter capability mode; now ALL lookups are strictly relative.
*/
REQUIRE(cap_enter());
/*
* Relative lookups on regular files or capabilities with CAP_LOOKUP
* ought to succeed.
*/
CHECK_SYSCALL_SUCCEEDS(openat, etc, "passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, etc_cap_ro, "passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, etc_cap_base, "passwd", O_RDONLY);
CHECK_SYSCALL_SUCCEEDS(openat, etc_cap_all, "passwd", O_RDONLY);
/*
* Lookup relative to capabilities without CAP_LOOKUP should fail.
*/
CHECK_NOTCAPABLE(openat, etc_cap, "passwd", O_RDONLY);
/*
* Absolute lookups should fail.
*/
CHECK_CAPMODE(openat, AT_FDCWD, "/etc/passwd", O_RDONLY);
CHECK_NOTCAPABLE(openat, etc, "/etc/passwd", O_RDONLY);
/*
* Lookups containing '..' should fail in capability mode.
*/
CHECK_NOTCAPABLE(openat, etc, "../etc/passwd", O_RDONLY);
CHECK_NOTCAPABLE(openat, etc_cap_ro, "../etc/passwd", O_RDONLY);
CHECK_NOTCAPABLE(openat, etc_cap_base, "../etc/passwd", O_RDONLY);
REQUIRE(fd = openat(etc, "passwd", O_RDONLY));
CHECK_SYSCALL_SUCCEEDS(cap_getrights, fd, &rights);
/*
* A file opened relative to a capability should itself be a capability.
*/
REQUIRE(fd = openat(etc_cap_base, "passwd", O_RDONLY));
CHECK_SYSCALL_SUCCEEDS(cap_getrights, fd, &rights);
CHECK_RIGHTS(rights, baserights);
return success;
}
|
