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
|
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <sys/socket.h>
#include <errno.h>
#include <unistd.h>
#include <dbus/dbus.h>
#include "log.h"
#include "dbus-common.h"
#include "util.h"
int bus_check_peercred(DBusConnection *c) {
int fd;
struct ucred ucred;
socklen_t l;
assert(c);
assert_se(dbus_connection_get_unix_fd(c, &fd));
l = sizeof(struct ucred);
if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l) < 0) {
log_error("SO_PEERCRED failed: %m");
return -errno;
}
if (l != sizeof(struct ucred)) {
log_error("SO_PEERCRED returned wrong size.");
return -E2BIG;
}
if (ucred.uid != 0)
return -EPERM;
return 1;
}
int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private, DBusError *error) {
DBusConnection *bus;
assert(_bus);
#define TIMEOUT_USEC (60*USEC_PER_SEC)
/* If we are root, then let's not go via the bus */
if (geteuid() == 0 && t == DBUS_BUS_SYSTEM) {
usec_t begin, tstamp;
if (!(bus = dbus_connection_open_private("unix:abstract=/org/freedesktop/systemd1/private", error)))
return -EIO;
if (bus_check_peercred(bus) < 0) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
dbus_set_error_const(error, DBUS_ERROR_ACCESS_DENIED, "Failed to verify owner of bus.");
return -EACCES;
}
begin = tstamp = now(CLOCK_MONOTONIC);
for (;;) {
if (tstamp > begin + TIMEOUT_USEC)
break;
if (dbus_connection_get_is_authenticated(bus))
break;
if (!dbus_connection_read_write_dispatch(bus, ((begin + TIMEOUT_USEC - tstamp) + USEC_PER_MSEC - 1) / USEC_PER_MSEC))
break;
tstamp = now(CLOCK_MONOTONIC);
}
if (!dbus_connection_get_is_connected(bus)) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
dbus_set_error_const(error, DBUS_ERROR_NO_SERVER, "Connection terminated during authentication.");
return -ECONNREFUSED;
}
if (!dbus_connection_get_is_authenticated(bus)) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
dbus_set_error_const(error, DBUS_ERROR_TIMEOUT, "Failed to authenticate in time.");
return -EACCES;
}
if (private)
*private = true;
} else {
if (!(bus = dbus_bus_get_private(t, error)))
return -EIO;
if (private)
*private = false;
}
dbus_connection_set_exit_on_disconnect(bus, FALSE);
*_bus = bus;
return 0;
}
const char *bus_error_message(const DBusError *error) {
assert(error);
/* Sometimes the D-Bus server is a little bit too verbose with
* its error messages, so let's override them here */
if (dbus_error_has_name(error, DBUS_ERROR_ACCESS_DENIED))
return "Access denied";
return error->message;
}
|
