summaryrefslogtreecommitdiffstats
path: root/src/daemon/polkit.c
blob: 08155cf2db76ff6fea30ee1b8700ab2370b3d695 (plain)
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
/***
  This file is part of PulseAudio.

  Copyright 2004-2006 Lennart Poettering
  Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB

  PulseAudio is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published
  by the Free Software Foundation; either version 2 of the License,
  or (at your option) any later version.

  PulseAudio 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 Lesser General Public License
  along with PulseAudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <unistd.h>
#include <stdlib.h>
#include <inttypes.h>

#include <dbus/dbus.h>
#include <polkit-dbus/polkit-dbus.h>

#include <pulsecore/log.h>
#include <pulsecore/macro.h>

#include "polkit.h"

int pa_polkit_check(const char *action_id) {
    int ret = -1;
    DBusError dbus_error;
    DBusConnection *bus = NULL;
    PolKitCaller *caller = NULL;
    PolKitAction *action = NULL;
    PolKitContext *context = NULL;
    PolKitError *polkit_error = NULL;
    PolKitSession *session = NULL;
    PolKitResult polkit_result;

    dbus_error_init(&dbus_error);

    if (!(bus = dbus_bus_get(DBUS_BUS_SYSTEM, &dbus_error))) {
        pa_log_error("Cannot connect to system bus: %s", dbus_error.message);
        goto finish;
    }

    /* There seems to be a bug in some versions of D-Bus that causes
     * dbus_shutdown() to call exit() when a connection without this
     * flag disabled was created during runtime.*/
    dbus_connection_set_exit_on_disconnect(bus, FALSE);

    if (!(caller = polkit_caller_new_from_pid(bus, getpid(), &dbus_error))) {
        pa_log_error("Cannot get caller from PID: %s", dbus_error.message);
        goto finish;
    }

    /* This function is called when PulseAudio is called SUID root. We
     * want to authenticate the real user that called us and not the
     * effective user we gained through being SUID root. Hence we
     * overwrite the UID caller data here explicitly, just for
     * paranoia. In fact PolicyKit should fill in the UID here anyway
     * -- an not the EUID or any other user id. */

    if (!(polkit_caller_set_uid(caller, getuid()))) {
        pa_log_error("Cannot set UID on caller object.");
        goto finish;
    }

    if (!(polkit_caller_get_ck_session(caller, &session))) {
        pa_log_error("Failed to get CK session.");
        goto finish;
    }

    /* We need to overwrite the UID in both the caller and the session
     * object */

    if (!(polkit_session_set_uid(session, getuid()))) {
        pa_log_error("Cannot set UID on session object.");
        goto finish;
    }

    if (!(action = polkit_action_new())) {
        pa_log_error("Cannot allocate PolKitAction.");
        goto finish;
    }

    if (!polkit_action_set_action_id(action, action_id)) {
        pa_log_error("Cannot set action_id");
        goto finish;
    }

    if (!(context = polkit_context_new())) {
        pa_log_error("Cannot allocate PolKitContext.");
        goto finish;
    }

    if (!polkit_context_init(context, &polkit_error)) {
        pa_log_error("Cannot initialize PolKitContext: %s", polkit_error_get_error_message(polkit_error));
        goto finish;
    }

    for (;;) {

        polkit_result = polkit_context_is_caller_authorized(context, action, caller, TRUE, &polkit_error);

        if (polkit_error_is_set(polkit_error)) {
            pa_log_error("Could not determine whether caller is authorized: %s", polkit_error_get_error_message(polkit_error));
            goto finish;
        }

        if (polkit_result == POLKIT_RESULT_ONLY_VIA_ADMIN_AUTH ||
            polkit_result == POLKIT_RESULT_ONLY_VIA_ADMIN_AUTH_KEEP_SESSION ||
            polkit_result == POLKIT_RESULT_ONLY_VIA_ADMIN_AUTH_KEEP_ALWAYS ||
            polkit_result == POLKIT_RESULT_ONLY_VIA_ADMIN_AUTH_ONE_SHOT ||
            polkit_result == POLKIT_RESULT_ONLY_VIA_SELF_AUTH ||
            polkit_result == POLKIT_RESULT_ONLY_VIA_SELF_AUTH_KEEP_SESSION ||
            polkit_result == POLKIT_RESULT_ONLY_VIA_SELF_AUTH_KEEP_ALWAYS ||
            polkit_result == POLKIT_RESULT_ONLY_VIA_SELF_AUTH_ONE_SHOT
        ) {

            if (polkit_auth_obtain(action_id, 0, getpid(), &dbus_error)) {
                polkit_result = POLKIT_RESULT_YES;
                break;
            }

            if (dbus_error_is_set(&dbus_error)) {
                pa_log_error("Cannot obtain auth: %s", dbus_error.message);
                goto finish;
            }
        }

        break;
    }

    if (polkit_result != POLKIT_RESULT_YES && polkit_result != POLKIT_RESULT_NO)
        pa_log_warn("PolicyKit responded with '%s'", polkit_result_to_string_representation(polkit_result));

    ret = polkit_result == POLKIT_RESULT_YES;

finish:

    if (caller)
        polkit_caller_unref(caller);

    if (action)
        polkit_action_unref(action);

    if (context)
        polkit_context_unref(context);

    if (bus)
        dbus_connection_unref(bus);

    dbus_error_free(&dbus_error);

    if (polkit_error)
        polkit_error_free(polkit_error);

    return ret;
}