summaryrefslogtreecommitdiff
path: root/src/dbus-common.c
blob: b23373c5d1d28946a876c61b87ec995053a14011 (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
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
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
/*-*- 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 <stdio.h>
#include <stdlib.h>
#include <dbus/dbus.h>
#include <string.h>

#include "log.h"
#include "dbus-common.h"
#include "util.h"
#include "def.h"
#include "strv.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;
}

static int sync_auth(DBusConnection *bus, DBusError *error) {
        usec_t begin, tstamp;

        assert(bus);

        /* This complexity should probably move into D-Bus itself:
         *
         * https://bugs.freedesktop.org/show_bug.cgi?id=35189 */

        begin = tstamp = now(CLOCK_MONOTONIC);
        for (;;) {

                if (tstamp > begin + DEFAULT_TIMEOUT_USEC)
                        break;

                if (dbus_connection_get_is_authenticated(bus))
                        break;

                if (!dbus_connection_read_write_dispatch(bus, ((begin + DEFAULT_TIMEOUT_USEC - tstamp) + USEC_PER_MSEC - 1) / USEC_PER_MSEC))
                        break;

                tstamp = now(CLOCK_MONOTONIC);
        }

        if (!dbus_connection_get_is_connected(bus)) {
                dbus_set_error_const(error, DBUS_ERROR_NO_SERVER, "Connection terminated during authentication.");
                return -ECONNREFUSED;
        }

        if (!dbus_connection_get_is_authenticated(bus)) {
                dbus_set_error_const(error, DBUS_ERROR_TIMEOUT, "Failed to authenticate in time.");
                return -EACCES;
        }

        return 0;
}

int bus_connect(DBusBusType t, DBusConnection **_bus, bool *private, DBusError *error) {
        DBusConnection *bus;
        int r;

        assert(_bus);

        /* If we are root, then let's not go via the bus */
        if (geteuid() == 0 && t == DBUS_BUS_SYSTEM) {

                if (!(bus = dbus_connection_open_private("unix:path=/run/systemd/private", error))) {
#ifndef LEGACY
                        dbus_error_free(error);

                        /* Retry with the pre v21 socket name, to ease upgrades */
                        if (!(bus = dbus_connection_open_private("unix:abstract=/org/freedesktop/systemd1/private", error)))
#endif
                                return -EIO;
                }

                dbus_connection_set_exit_on_disconnect(bus, FALSE);

                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;
                }

                if (private)
                        *private = true;

        } else {
                if (!(bus = dbus_bus_get_private(t, error)))
                        return -EIO;

                dbus_connection_set_exit_on_disconnect(bus, FALSE);

                if (private)
                        *private = false;
        }

        if ((r = sync_auth(bus, error)) < 0) {
                dbus_connection_close(bus);
                dbus_connection_unref(bus);
                return r;
        }

        *_bus = bus;
        return 0;
}

int bus_connect_system_ssh(const char *user, const char *host, DBusConnection **_bus, DBusError *error) {
        DBusConnection *bus;
        char *p = NULL;
        int r;

        assert(_bus);
        assert(user || host);

        if (user && host)
                asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@%s,argv3=systemd-stdio-bridge", user, host);
        else if (user)
                asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s@localhost,argv3=systemd-stdio-bridge", user);
        else if (host)
                asprintf(&p, "exec:path=ssh,argv1=-xT,argv2=%s,argv3=systemd-stdio-bridge", host);

        if (!p) {
                dbus_set_error_const(error, DBUS_ERROR_NO_MEMORY, NULL);
                return -ENOMEM;
        }

        bus = dbus_connection_open_private(p, error);
        free(p);

        if (!bus)
                return -EIO;

        dbus_connection_set_exit_on_disconnect(bus, FALSE);

        if ((r = sync_auth(bus, error)) < 0) {
                dbus_connection_close(bus);
                dbus_connection_unref(bus);
                return r;
        }

        if (!dbus_bus_register(bus, error)) {
                dbus_connection_close(bus);
                dbus_connection_unref(bus);
                return r;
        }

        *_bus = bus;
        return 0;
}

int bus_connect_system_polkit(DBusConnection **_bus, DBusError *error) {
        DBusConnection *bus;
        int r;

        assert(_bus);

        /* Don't bother with PolicyKit if we are root */
        if (geteuid() == 0)
                return bus_connect(DBUS_BUS_SYSTEM, _bus, NULL, error);

        if (!(bus = dbus_connection_open_private("exec:path=pkexec,argv1=" SYSTEMD_STDIO_BRIDGE_BINARY_PATH, error)))
                return -EIO;

        dbus_connection_set_exit_on_disconnect(bus, FALSE);

        if ((r = sync_auth(bus, error)) < 0) {
                dbus_connection_close(bus);
                dbus_connection_unref(bus);
                return r;
        }

        if (!dbus_bus_register(bus, error)) {
                dbus_connection_close(bus);
                dbus_connection_unref(bus);
                return r;
        }

        *_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;
}

DBusHandlerResult bus_default_message_handler(
                DBusConnection *c,
                DBusMessage *message,
                const char *introspection,
                const char *interfaces,
                const BusProperty *properties) {

        DBusError error;
        DBusMessage *reply = NULL;
        int r;

        assert(c);
        assert(message);

        dbus_error_init(&error);

        if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Introspectable", "Introspect") && introspection) {

                if (!(reply = dbus_message_new_method_return(message)))
                        goto oom;

                if (!dbus_message_append_args(reply, DBUS_TYPE_STRING, &introspection, DBUS_TYPE_INVALID))
                        goto oom;

        } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "Get") && properties) {
                const char *interface, *property;
                const BusProperty *p;

                if (!dbus_message_get_args(
                            message,
                            &error,
                            DBUS_TYPE_STRING, &interface,
                            DBUS_TYPE_STRING, &property,
                            DBUS_TYPE_INVALID))
                        return bus_send_error_reply(c, message, &error, -EINVAL);

                for (p = properties; p->property; p++)
                        if (streq(p->interface, interface) && streq(p->property, property))
                                break;

                if (p->property) {
                        DBusMessageIter iter, sub;

                        if (!(reply = dbus_message_new_method_return(message)))
                                goto oom;

                        dbus_message_iter_init_append(reply, &iter);

                        if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT, p->signature, &sub))
                                goto oom;

                        if ((r = p->append(&sub, property, (void*) p->data)) < 0) {

                                if (r == -ENOMEM)
                                        goto oom;

                                dbus_message_unref(reply);
                                return bus_send_error_reply(c, message, NULL, r);
                        }

                        if (!dbus_message_iter_close_container(&iter, &sub))
                                goto oom;
                } else {
                        if (!nulstr_contains(interfaces, interface))
                                dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
                        else
                                dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_PROPERTY, "Unknown property");

                        return bus_send_error_reply(c, message, &error, -EINVAL);
                }

        } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "GetAll") && properties) {
                const char *interface;
                const BusProperty *p;
                DBusMessageIter iter, sub, sub2, sub3;

                if (!dbus_message_get_args(
                            message,
                            &error,
                            DBUS_TYPE_STRING, &interface,
                            DBUS_TYPE_INVALID))
                        return bus_send_error_reply(c, message, &error, -EINVAL);

                if (interface[0] && !nulstr_contains(interfaces, interface)) {
                        dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
                        return bus_send_error_reply(c, message, &error, -EINVAL);
                }

                if (!(reply = dbus_message_new_method_return(message)))
                        goto oom;

                dbus_message_iter_init_append(reply, &iter);

                if (!dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub))
                        goto oom;

                for (p = properties; p->property; p++) {
                        if (interface[0] && !streq(p->interface, interface))
                                continue;

                        if (!dbus_message_iter_open_container(&sub, DBUS_TYPE_DICT_ENTRY, NULL, &sub2) ||
                            !dbus_message_iter_append_basic(&sub2, DBUS_TYPE_STRING, &p->property) ||
                            !dbus_message_iter_open_container(&sub2, DBUS_TYPE_VARIANT, p->signature, &sub3))
                                goto oom;

                        if ((r = p->append(&sub3, p->property, (void*) p->data)) < 0) {

                                if (r == -ENOMEM)
                                        goto oom;

                                dbus_message_unref(reply);
                                return bus_send_error_reply(c, message, NULL, r);
                        }

                        if (!dbus_message_iter_close_container(&sub2, &sub3) ||
                            !dbus_message_iter_close_container(&sub, &sub2))
                                goto oom;
                }

                if (!dbus_message_iter_close_container(&iter, &sub))
                        goto oom;

        } else if (dbus_message_is_method_call(message, "org.freedesktop.DBus.Properties", "Set") && properties) {
                const char *interface, *property;
                DBusMessageIter iter;
                const BusProperty *p;

                if (!dbus_message_iter_init(message, &iter) ||
                    dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
                        return bus_send_error_reply(c, message, NULL, -EINVAL);

                dbus_message_iter_get_basic(&iter, &interface);

                if (!dbus_message_iter_next(&iter) ||
                    dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING)
                        return bus_send_error_reply(c, message, NULL, -EINVAL);

                dbus_message_iter_get_basic(&iter, &property);

                if (!dbus_message_iter_next(&iter) ||
                    dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT ||
                    dbus_message_iter_has_next(&iter))
                        return bus_send_error_reply(c, message, NULL, -EINVAL);

                for (p = properties; p->property; p++)
                        if (streq(p->interface, interface) && streq(p->property, property))
                                break;

                if (p->set) {
                        DBusMessageIter sub;
                        char *sig;

                        dbus_message_iter_recurse(&iter, &sub);

                        if (!(sig = dbus_message_iter_get_signature(&sub)))
                                goto oom;

                        if (!streq(sig, p->signature)) {
                                dbus_free(sig);
                                return bus_send_error_reply(c, message, NULL, -EINVAL);
                        }

                        dbus_free(sig);

                        if ((r = p->set(&sub, property)) < 0) {
                                if (r == -ENOMEM)
                                        goto oom;
                                return bus_send_error_reply(c, message, NULL, r);
                        }

                        if (!(reply = dbus_message_new_method_return(message)))
                                goto oom;
                } else {
                        if (p->property)
                                dbus_set_error_const(&error, DBUS_ERROR_PROPERTY_READ_ONLY, "Property read-only");
                        else if (!nulstr_contains(interfaces, interface))
                                dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
                        else
                                dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_PROPERTY, "Unknown property");

                        return bus_send_error_reply(c, message, &error, -EINVAL);
                }

        } else if (!nulstr_contains(interfaces, dbus_message_get_interface(message))) {
                dbus_set_error_const(&error, DBUS_ERROR_UNKNOWN_INTERFACE, "Unknown interface");
                return bus_send_error_reply(c, message, &error, -EINVAL);
        }

        if (reply) {
                if (!dbus_connection_send(c, reply, NULL))
                        goto oom;

                dbus_message_unref(reply);
                return DBUS_HANDLER_RESULT_HANDLED;
        }

        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

oom:
        if (reply)
                dbus_message_unref(reply);

        dbus_error_free(&error);

        return DBUS_HANDLER_RESULT_NEED_MEMORY;
}

int bus_property_append_string(DBusMessageIter *i, const char *property, void *data) {
        const char *t = data;

        assert(i);
        assert(property);

        if (!t)
                t = "";

        if (!dbus_message_iter_append_basic(i, DBUS_TYPE_STRING, &t))
                return -ENOMEM;

        return 0;
}

int bus_property_append_strv(DBusMessageIter *i, const char *property, void *data) {
        DBusMessageIter sub;
        char **t = data;

        assert(i);
        assert(property);

        if (!dbus_message_iter_open_container(i, DBUS_TYPE_ARRAY, "s", &sub))
                return -ENOMEM;

        STRV_FOREACH(t, t)
                if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, t))
                        return -ENOMEM;

        if (!dbus_message_iter_close_container(i, &sub))
                return -ENOMEM;

        return 0;
}

int bus_property_append_bool(DBusMessageIter *i, const char *property, void *data) {
        bool *b = data;
        dbus_bool_t db;

        assert(i);
        assert(property);
        assert(b);

        db = *b;

        if (!dbus_message_iter_append_basic(i, DBUS_TYPE_BOOLEAN, &db))
                return -ENOMEM;

        return 0;
}

int bus_property_append_uint64(DBusMessageIter *i, const char *property, void *data) {
        assert(i);
        assert(property);
        assert(data);

        /* Let's ensure that pid_t is actually 64bit, and hence this
         * function can be used for usec_t */
        assert_cc(sizeof(uint64_t) == sizeof(usec_t));

        if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, data))
                return -ENOMEM;

        return 0;
}

int bus_property_append_uint32(DBusMessageIter *i, const char *property, void *data) {
        assert(i);
        assert(property);
        assert(data);

        /* Let's ensure that pid_t and mode_t is actually 32bit, and
         * hence this function can be used for pid_t/mode_t */
        assert_cc(sizeof(uint32_t) == sizeof(pid_t));
        assert_cc(sizeof(uint32_t) == sizeof(mode_t));
        assert_cc(sizeof(uint32_t) == sizeof(unsigned));

        if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT32, data))
                return -ENOMEM;

        return 0;
}

int bus_property_append_int32(DBusMessageIter *i, const char *property, void *data) {
        assert(i);
        assert(property);
        assert(data);

        assert_cc(sizeof(int32_t) == sizeof(int));

        if (!dbus_message_iter_append_basic(i, DBUS_TYPE_INT32, data))
                return -ENOMEM;

        return 0;
}

int bus_property_append_size(DBusMessageIter *i, const char *property, void *data) {
        uint64_t u;

        assert(i);
        assert(property);
        assert(data);

        u = (uint64_t) *(size_t*) data;

        if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, &u))
                return -ENOMEM;

        return 0;
}

int bus_property_append_ul(DBusMessageIter *i, const char *property, void *data) {
        uint64_t u;

        assert(i);
        assert(property);
        assert(data);

        u = (uint64_t) *(unsigned long*) data;

        if (!dbus_message_iter_append_basic(i, DBUS_TYPE_UINT64, &u))
                return -ENOMEM;

        return 0;
}

const char *bus_errno_to_dbus(int error) {

        switch(error) {

        case -EINVAL:
                return DBUS_ERROR_INVALID_ARGS;

        case -ENOMEM:
                return DBUS_ERROR_NO_MEMORY;

        case -EPERM:
        case -EACCES:
                return DBUS_ERROR_ACCESS_DENIED;

        case -ESRCH:
                return DBUS_ERROR_UNIX_PROCESS_ID_UNKNOWN;

        case -ENOENT:
                return DBUS_ERROR_FILE_NOT_FOUND;

        case -EEXIST:
                return DBUS_ERROR_FILE_EXISTS;

        case -ETIMEDOUT:
        case -ETIME:
                return DBUS_ERROR_TIMEOUT;

        case -EIO:
                return DBUS_ERROR_IO_ERROR;

        case -ENETRESET:
        case -ECONNABORTED:
        case -ECONNRESET:
                return DBUS_ERROR_DISCONNECTED;
        }

        return DBUS_ERROR_FAILED;
}

DBusHandlerResult bus_send_error_reply(DBusConnection *c, DBusMessage *message, DBusError *berror, int error) {
        DBusMessage *reply = NULL;
        const char *name, *text;

        if (berror && dbus_error_is_set(berror)) {
                name = berror->name;
                text = berror->message;
        } else {
                name = bus_errno_to_dbus(error);
                text = strerror(-error);
        }

        if (!(reply = dbus_message_new_error(message, name, text)))
                goto oom;

        if (!dbus_connection_send(c, reply, NULL))
                goto oom;

        dbus_message_unref(reply);

        if (berror)
                dbus_error_free(berror);

        return DBUS_HANDLER_RESULT_HANDLED;

oom:
        if (reply)
                dbus_message_unref(reply);

        if (berror)
                dbus_error_free(berror);

        return DBUS_HANDLER_RESULT_NEED_MEMORY;
}

DBusMessage* bus_properties_changed_new(const char *path, const char *interface, const char *properties) {
        DBusMessage *m;
        DBusMessageIter iter, sub;
        const char *i;

        assert(interface);
        assert(properties);

        if (!(m = dbus_message_new_signal(path, "org.freedesktop.DBus.Properties", "PropertiesChanged")))
                goto oom;

        dbus_message_iter_init_append(m, &iter);

        /* We won't send any property values, since they might be
         * large and sometimes not cheap to generated */

        if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &interface) ||
            !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "{sv}", &sub) ||
            !dbus_message_iter_close_container(&iter, &sub) ||
            !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "s", &sub))
                goto oom;

        NULSTR_FOREACH(i, properties)
                if (!dbus_message_iter_append_basic(&sub, DBUS_TYPE_STRING, &i))
                        goto oom;

        if (!dbus_message_iter_close_container(&iter, &sub))
                goto oom;

        return m;

oom:
        if (m)
                dbus_message_unref(m);

        return NULL;
}