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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
/* Copyright (c) 2015-2019, The Tor Project, Inc. */
/* See LICENSE for licensing information */
#include "core/or/or.h"
#include "lib/process/setuid.h"
#ifdef HAVE_SYS_CAPABILITY_H
#include <sys/capability.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#define TEST_BUILT_WITH_CAPS 0
#define TEST_HAVE_CAPS 1
#define TEST_ROOT_CAN_BIND_LOW 2
#define TEST_SETUID 3
#define TEST_SETUID_KEEPCAPS 4
#define TEST_SETUID_STRICT 5
static const struct {
const char *name;
int test_id;
} which_test[] = {
{ "built-with-caps", TEST_BUILT_WITH_CAPS },
{ "have-caps", TEST_HAVE_CAPS },
{ "root-bind-low", TEST_ROOT_CAN_BIND_LOW },
{ "setuid", TEST_SETUID },
{ "setuid-keepcaps", TEST_SETUID_KEEPCAPS },
{ "setuid-strict", TEST_SETUID_STRICT },
{ NULL, 0 }
};
#if !defined(_WIN32)
/* 0 on no, 1 on yes, -1 on failure. */
static int
check_can_bind_low_ports(void)
{
int port;
struct sockaddr_in sin;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
for (port = 600; port < 1024; ++port) {
sin.sin_port = htons(port);
tor_socket_t fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (! SOCKET_OK(fd)) {
perror("socket");
return -1;
}
int one = 1;
if (setsockopt(fd, SOL_SOCKET,SO_REUSEADDR, (void*)&one,
(socklen_t)sizeof(one))) {
perror("setsockopt");
tor_close_socket_simple(fd);
return -1;
}
int res = bind(fd, (struct sockaddr *)&sin, sizeof(sin));
tor_close_socket_simple(fd);
if (res == 0) {
/* bind was successful */
return 1;
} else if (errno == EACCES || errno == EPERM) {
/* Got a permission-denied error. */
return 0;
} else if (errno == EADDRINUSE) {
/* Huh; somebody is using that port. */
} else {
perror("bind");
}
}
return -1;
}
#endif /* !defined(_WIN32) */
int
main(int argc, char **argv)
{
#if defined(_WIN32)
(void) argc;
(void) argv;
(void) which_test;
fprintf(stderr, "This test is not supported on your OS.\n");
return 77;
#else /* !(defined(_WIN32)) */
const char *username;
const char *testname;
if (argc != 3) {
fprintf(stderr, "I want 2 arguments: a username and a command.\n");
return 1;
}
if (getuid() != 0) {
fprintf(stderr, "This test only works when it's run as root.\n");
return 1;
}
username = argv[1];
testname = argv[2];
int test_id = -1;
int i;
for (i = 0; which_test[i].name; ++i) {
if (!strcmp(which_test[i].name, testname)) {
test_id = which_test[i].test_id;
break;
}
}
if (test_id == -1) {
fprintf(stderr, "Unrecognized test '%s'\n", testname);
return 1;
}
#ifdef HAVE_LINUX_CAPABILITIES
const int have_cap_support = 1;
#else
const int have_cap_support = 0;
#endif
int okay;
init_logging(1);
log_severity_list_t sev;
memset(&sev, 0, sizeof(sev));
set_log_severity_config(LOG_WARN, LOG_ERR, &sev);
add_stream_log(&sev, "", fileno(stderr));
switch (test_id)
{
case TEST_BUILT_WITH_CAPS:
/* Succeed if we were built with capability support. */
okay = have_cap_support;
break;
case TEST_HAVE_CAPS:
/* Succeed if "capabilities work" == "we were built with capability
* support." */
okay = have_cap_support == have_capability_support();
break;
case TEST_ROOT_CAN_BIND_LOW:
/* Succeed if root can bind low ports. */
okay = check_can_bind_low_ports() == 1;
break;
case TEST_SETUID:
/* Succeed if we can do a setuid with no capability retention, and doing
* so makes us lose the ability to bind low ports */
case TEST_SETUID_KEEPCAPS:
/* Succeed if we can do a setuid with capability retention, and doing so
* does not make us lose the ability to bind low ports */
{
int keepcaps = (test_id == TEST_SETUID_KEEPCAPS);
okay = switch_id(username, keepcaps ? SWITCH_ID_KEEP_BINDLOW : 0) == 0;
if (okay) {
okay = check_can_bind_low_ports() == keepcaps;
}
break;
}
case TEST_SETUID_STRICT:
/* Succeed if, after a setuid, we cannot setuid back, and we cannot
* re-grab any capabilities. */
okay = switch_id(username, SWITCH_ID_KEEP_BINDLOW) == 0;
if (okay) {
/* We'd better not be able to setuid back! */
if (setuid(0) == 0 || errno != EPERM) {
okay = 0;
}
}
#ifdef HAVE_LINUX_CAPABILITIES
if (okay) {
cap_t caps = cap_get_proc();
const cap_value_t caplist[] = {
CAP_SETUID,
};
cap_set_flag(caps, CAP_PERMITTED, 1, caplist, CAP_SET);
if (cap_set_proc(caps) == 0 || errno != EPERM) {
okay = 0;
}
cap_free(caps);
}
#endif /* defined(HAVE_LINUX_CAPABILITIES) */
break;
default:
fprintf(stderr, "Unsupported test '%s'\n", testname);
okay = 0;
break;
}
if (!okay) {
fprintf(stderr, "Test %s failed!\n", testname);
}
return (okay ? 0 : 1);
#endif /* defined(_WIN32) */
}
|
