]>
Commit | Line | Data |
---|---|---|
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ | |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2013 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <endian.h> | |
23 | #include <assert.h> | |
24 | #include <stdlib.h> | |
25 | #include <unistd.h> | |
26 | #include <sys/poll.h> | |
27 | #include <byteswap.h> | |
28 | ||
29 | #include "util.h" | |
30 | #include "macro.h" | |
31 | #include "missing.h" | |
32 | #include "strv.h" | |
33 | #include "utf8.h" | |
34 | #include "sd-daemon.h" | |
35 | ||
36 | #include "sd-bus.h" | |
37 | #include "bus-socket.h" | |
38 | #include "bus-internal.h" | |
39 | #include "bus-message.h" | |
40 | ||
41 | #define SNDBUF_SIZE (8*1024*1024) | |
42 | ||
43 | static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) { | |
44 | ||
45 | while (size > 0) { | |
46 | struct iovec *i = iov + *idx; | |
47 | ||
48 | if (i->iov_len > size) { | |
49 | i->iov_base = (uint8_t*) i->iov_base + size; | |
50 | i->iov_len -= size; | |
51 | return; | |
52 | } | |
53 | ||
54 | size -= i->iov_len; | |
55 | ||
56 | i->iov_base = NULL; | |
57 | i->iov_len = 0; | |
58 | ||
59 | (*idx) ++; | |
60 | } | |
61 | } | |
62 | ||
63 | static int append_iovec(sd_bus_message *m, const void *p, size_t sz) { | |
64 | assert(m); | |
65 | assert(p); | |
66 | assert(sz > 0); | |
67 | ||
68 | m->iovec[m->n_iovec].iov_base = (void*) p; | |
69 | m->iovec[m->n_iovec].iov_len = sz; | |
70 | m->n_iovec++; | |
71 | ||
72 | return 0; | |
73 | } | |
74 | ||
75 | static int bus_message_setup_iovec(sd_bus_message *m) { | |
76 | struct bus_body_part *part; | |
77 | unsigned n, i; | |
78 | int r; | |
79 | ||
80 | assert(m); | |
81 | assert(m->sealed); | |
82 | ||
83 | if (m->n_iovec > 0) | |
84 | return 0; | |
85 | ||
86 | assert(!m->iovec); | |
87 | ||
88 | n = 1 + m->n_body_parts; | |
89 | if (n < ELEMENTSOF(m->iovec_fixed)) | |
90 | m->iovec = m->iovec_fixed; | |
91 | else { | |
92 | m->iovec = new(struct iovec, n); | |
93 | if (!m->iovec) { | |
94 | r = -ENOMEM; | |
95 | goto fail; | |
96 | } | |
97 | } | |
98 | ||
99 | r = append_iovec(m, m->header, BUS_MESSAGE_BODY_BEGIN(m)); | |
100 | if (r < 0) | |
101 | goto fail; | |
102 | ||
103 | MESSAGE_FOREACH_PART(part, i, m) { | |
104 | r = bus_body_part_map(part); | |
105 | if (r < 0) | |
106 | goto fail; | |
107 | ||
108 | r = append_iovec(m, part->data, part->size); | |
109 | if (r < 0) | |
110 | goto fail; | |
111 | } | |
112 | ||
113 | assert(n == m->n_iovec); | |
114 | ||
115 | return 0; | |
116 | ||
117 | fail: | |
118 | m->poisoned = true; | |
119 | return r; | |
120 | } | |
121 | ||
122 | bool bus_socket_auth_needs_write(sd_bus *b) { | |
123 | ||
124 | unsigned i; | |
125 | ||
126 | if (b->auth_index >= ELEMENTSOF(b->auth_iovec)) | |
127 | return false; | |
128 | ||
129 | for (i = b->auth_index; i < ELEMENTSOF(b->auth_iovec); i++) { | |
130 | struct iovec *j = b->auth_iovec + i; | |
131 | ||
132 | if (j->iov_len > 0) | |
133 | return true; | |
134 | } | |
135 | ||
136 | return false; | |
137 | } | |
138 | ||
139 | static int bus_socket_write_auth(sd_bus *b) { | |
140 | ssize_t k; | |
141 | ||
142 | assert(b); | |
143 | assert(b->state == BUS_AUTHENTICATING); | |
144 | ||
145 | if (!bus_socket_auth_needs_write(b)) | |
146 | return 0; | |
147 | ||
148 | if (b->prefer_writev) | |
149 | k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index); | |
150 | else { | |
151 | struct msghdr mh; | |
152 | zero(mh); | |
153 | ||
154 | mh.msg_iov = b->auth_iovec + b->auth_index; | |
155 | mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index; | |
156 | ||
157 | k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL); | |
158 | if (k < 0 && errno == ENOTSOCK) { | |
159 | b->prefer_writev = true; | |
160 | k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index); | |
161 | } | |
162 | } | |
163 | ||
164 | if (k < 0) | |
165 | return errno == EAGAIN ? 0 : -errno; | |
166 | ||
167 | iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k); | |
168 | return 1; | |
169 | } | |
170 | ||
171 | static int bus_socket_auth_verify_client(sd_bus *b) { | |
172 | char *e, *f, *start; | |
173 | sd_id128_t peer; | |
174 | unsigned i; | |
175 | int r; | |
176 | ||
177 | assert(b); | |
178 | ||
179 | /* We expect two response lines: "OK" and possibly | |
180 | * "AGREE_UNIX_FD" */ | |
181 | ||
182 | e = memmem(b->rbuffer, b->rbuffer_size, "\r\n", 2); | |
183 | if (!e) | |
184 | return 0; | |
185 | ||
186 | if (b->hello_flags & KDBUS_HELLO_ACCEPT_FD) { | |
187 | f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2); | |
188 | if (!f) | |
189 | return 0; | |
190 | ||
191 | start = f + 2; | |
192 | } else { | |
193 | f = NULL; | |
194 | start = e + 2; | |
195 | } | |
196 | ||
197 | /* Nice! We got all the lines we need. First check the OK | |
198 | * line */ | |
199 | ||
200 | if (e - (char*) b->rbuffer != 3 + 32) | |
201 | return -EPERM; | |
202 | ||
203 | if (memcmp(b->rbuffer, "OK ", 3)) | |
204 | return -EPERM; | |
205 | ||
206 | b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL; | |
207 | ||
208 | for (i = 0; i < 32; i += 2) { | |
209 | int x, y; | |
210 | ||
211 | x = unhexchar(((char*) b->rbuffer)[3 + i]); | |
212 | y = unhexchar(((char*) b->rbuffer)[3 + i + 1]); | |
213 | ||
214 | if (x < 0 || y < 0) | |
215 | return -EINVAL; | |
216 | ||
217 | peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y); | |
218 | } | |
219 | ||
220 | if (!sd_id128_equal(b->server_id, SD_ID128_NULL) && | |
221 | !sd_id128_equal(b->server_id, peer)) | |
222 | return -EPERM; | |
223 | ||
224 | b->server_id = peer; | |
225 | ||
226 | /* And possibly check the second line, too */ | |
227 | ||
228 | if (f) | |
229 | b->can_fds = | |
230 | (f - e == strlen("\r\nAGREE_UNIX_FD")) && | |
231 | memcmp(e + 2, "AGREE_UNIX_FD", strlen("AGREE_UNIX_FD")) == 0; | |
232 | ||
233 | b->rbuffer_size -= (start - (char*) b->rbuffer); | |
234 | memmove(b->rbuffer, start, b->rbuffer_size); | |
235 | ||
236 | r = bus_start_running(b); | |
237 | if (r < 0) | |
238 | return r; | |
239 | ||
240 | return 1; | |
241 | } | |
242 | ||
243 | static bool line_equals(const char *s, size_t m, const char *line) { | |
244 | size_t l; | |
245 | ||
246 | l = strlen(line); | |
247 | if (l != m) | |
248 | return false; | |
249 | ||
250 | return memcmp(s, line, l) == 0; | |
251 | } | |
252 | ||
253 | static bool line_begins(const char *s, size_t m, const char *word) { | |
254 | size_t l; | |
255 | ||
256 | l = strlen(word); | |
257 | if (m < l) | |
258 | return false; | |
259 | ||
260 | if (memcmp(s, word, l) != 0) | |
261 | return false; | |
262 | ||
263 | return m == l || (m > l && s[l] == ' '); | |
264 | } | |
265 | ||
266 | static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) { | |
267 | _cleanup_free_ char *token = NULL; | |
268 | ||
269 | if (!b->anonymous_auth) | |
270 | return 0; | |
271 | ||
272 | if (l <= 0) | |
273 | return 1; | |
274 | ||
275 | assert(p[0] == ' '); | |
276 | p++; l--; | |
277 | ||
278 | if (l % 2 != 0) | |
279 | return 0; | |
280 | token = unhexmem(p, l); | |
281 | if (!token) | |
282 | return -ENOMEM; | |
283 | ||
284 | if (memchr(token, 0, l/2)) | |
285 | return 0; | |
286 | ||
287 | return !!utf8_is_valid(token); | |
288 | } | |
289 | ||
290 | static int verify_external_token(sd_bus *b, const char *p, size_t l) { | |
291 | _cleanup_free_ char *token = NULL; | |
292 | uid_t u; | |
293 | int r; | |
294 | ||
295 | /* We don't do any real authentication here. Instead, we if | |
296 | * the owner of this bus wanted authentication he should have | |
297 | * checked SO_PEERCRED before even creating the bus object. */ | |
298 | ||
299 | if (!b->anonymous_auth && !b->ucred_valid) | |
300 | return 0; | |
301 | ||
302 | if (l <= 0) | |
303 | return 1; | |
304 | ||
305 | assert(p[0] == ' '); | |
306 | p++; l--; | |
307 | ||
308 | if (l % 2 != 0) | |
309 | return 0; | |
310 | ||
311 | token = unhexmem(p, l); | |
312 | if (!token) | |
313 | return -ENOMEM; | |
314 | ||
315 | if (memchr(token, 0, l/2)) | |
316 | return 0; | |
317 | ||
318 | r = parse_uid(token, &u); | |
319 | if (r < 0) | |
320 | return 0; | |
321 | ||
322 | /* We ignore the passed value if anonymous authentication is | |
323 | * on anyway. */ | |
324 | if (!b->anonymous_auth && u != b->ucred.uid) | |
325 | return 0; | |
326 | ||
327 | return 1; | |
328 | } | |
329 | ||
330 | static int bus_socket_auth_write(sd_bus *b, const char *t) { | |
331 | char *p; | |
332 | size_t l; | |
333 | ||
334 | assert(b); | |
335 | assert(t); | |
336 | ||
337 | /* We only make use of the first iovec */ | |
338 | assert(b->auth_index == 0 || b->auth_index == 1); | |
339 | ||
340 | l = strlen(t); | |
341 | p = malloc(b->auth_iovec[0].iov_len + l); | |
342 | if (!p) | |
343 | return -ENOMEM; | |
344 | ||
345 | memcpy(p, b->auth_iovec[0].iov_base, b->auth_iovec[0].iov_len); | |
346 | memcpy(p + b->auth_iovec[0].iov_len, t, l); | |
347 | ||
348 | b->auth_iovec[0].iov_base = p; | |
349 | b->auth_iovec[0].iov_len += l; | |
350 | ||
351 | free(b->auth_buffer); | |
352 | b->auth_buffer = p; | |
353 | b->auth_index = 0; | |
354 | return 0; | |
355 | } | |
356 | ||
357 | static int bus_socket_auth_write_ok(sd_bus *b) { | |
358 | char t[3 + 32 + 2 + 1]; | |
359 | ||
360 | assert(b); | |
361 | ||
362 | snprintf(t, sizeof(t), "OK " SD_ID128_FORMAT_STR "\r\n", SD_ID128_FORMAT_VAL(b->server_id)); | |
363 | char_array_0(t); | |
364 | ||
365 | return bus_socket_auth_write(b, t); | |
366 | } | |
367 | ||
368 | static int bus_socket_auth_verify_server(sd_bus *b) { | |
369 | char *e; | |
370 | const char *line; | |
371 | size_t l; | |
372 | bool processed = false; | |
373 | int r; | |
374 | ||
375 | assert(b); | |
376 | ||
377 | if (b->rbuffer_size < 1) | |
378 | return 0; | |
379 | ||
380 | /* First char must be a NUL byte */ | |
381 | if (*(char*) b->rbuffer != 0) | |
382 | return -EIO; | |
383 | ||
384 | if (b->rbuffer_size < 3) | |
385 | return 0; | |
386 | ||
387 | /* Begin with the first line */ | |
388 | if (b->auth_rbegin <= 0) | |
389 | b->auth_rbegin = 1; | |
390 | ||
391 | for (;;) { | |
392 | /* Check if line is complete */ | |
393 | line = (char*) b->rbuffer + b->auth_rbegin; | |
394 | e = memmem(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2); | |
395 | if (!e) | |
396 | return processed; | |
397 | ||
398 | l = e - line; | |
399 | ||
400 | if (line_begins(line, l, "AUTH ANONYMOUS")) { | |
401 | ||
402 | r = verify_anonymous_token(b, line + 14, l - 14); | |
403 | if (r < 0) | |
404 | return r; | |
405 | if (r == 0) | |
406 | r = bus_socket_auth_write(b, "REJECTED\r\n"); | |
407 | else { | |
408 | b->auth = BUS_AUTH_ANONYMOUS; | |
409 | r = bus_socket_auth_write_ok(b); | |
410 | } | |
411 | ||
412 | } else if (line_begins(line, l, "AUTH EXTERNAL")) { | |
413 | ||
414 | r = verify_external_token(b, line + 13, l - 13); | |
415 | if (r < 0) | |
416 | return r; | |
417 | if (r == 0) | |
418 | r = bus_socket_auth_write(b, "REJECTED\r\n"); | |
419 | else { | |
420 | b->auth = BUS_AUTH_EXTERNAL; | |
421 | r = bus_socket_auth_write_ok(b); | |
422 | } | |
423 | ||
424 | } else if (line_begins(line, l, "AUTH")) | |
425 | r = bus_socket_auth_write(b, "REJECTED EXTERNAL ANONYMOUS\r\n"); | |
426 | else if (line_equals(line, l, "CANCEL") || | |
427 | line_begins(line, l, "ERROR")) { | |
428 | ||
429 | b->auth = _BUS_AUTH_INVALID; | |
430 | r = bus_socket_auth_write(b, "REJECTED\r\n"); | |
431 | ||
432 | } else if (line_equals(line, l, "BEGIN")) { | |
433 | ||
434 | if (b->auth == _BUS_AUTH_INVALID) | |
435 | r = bus_socket_auth_write(b, "ERROR\r\n"); | |
436 | else { | |
437 | /* We can't leave from the auth phase | |
438 | * before we haven't written | |
439 | * everything queued, so let's check | |
440 | * that */ | |
441 | ||
442 | if (bus_socket_auth_needs_write(b)) | |
443 | return 1; | |
444 | ||
445 | b->rbuffer_size -= (e + 2 - (char*) b->rbuffer); | |
446 | memmove(b->rbuffer, e + 2, b->rbuffer_size); | |
447 | return bus_start_running(b); | |
448 | } | |
449 | ||
450 | } else if (line_begins(line, l, "DATA")) { | |
451 | ||
452 | if (b->auth == _BUS_AUTH_INVALID) | |
453 | r = bus_socket_auth_write(b, "ERROR\r\n"); | |
454 | else { | |
455 | if (b->auth == BUS_AUTH_ANONYMOUS) | |
456 | r = verify_anonymous_token(b, line + 4, l - 4); | |
457 | else | |
458 | r = verify_external_token(b, line + 4, l - 4); | |
459 | ||
460 | if (r < 0) | |
461 | return r; | |
462 | if (r == 0) { | |
463 | b->auth = _BUS_AUTH_INVALID; | |
464 | r = bus_socket_auth_write(b, "REJECTED\r\n"); | |
465 | } else | |
466 | r = bus_socket_auth_write_ok(b); | |
467 | } | |
468 | } else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) { | |
469 | if (b->auth == _BUS_AUTH_INVALID || !(b->hello_flags & KDBUS_HELLO_ACCEPT_FD)) | |
470 | r = bus_socket_auth_write(b, "ERROR\r\n"); | |
471 | else { | |
472 | b->can_fds = true; | |
473 | r = bus_socket_auth_write(b, "AGREE_UNIX_FD\r\n"); | |
474 | } | |
475 | } else | |
476 | r = bus_socket_auth_write(b, "ERROR\r\n"); | |
477 | ||
478 | if (r < 0) | |
479 | return r; | |
480 | ||
481 | b->auth_rbegin = e + 2 - (char*) b->rbuffer; | |
482 | ||
483 | processed = true; | |
484 | } | |
485 | } | |
486 | ||
487 | static int bus_socket_auth_verify(sd_bus *b) { | |
488 | assert(b); | |
489 | ||
490 | if (b->is_server) | |
491 | return bus_socket_auth_verify_server(b); | |
492 | else | |
493 | return bus_socket_auth_verify_client(b); | |
494 | } | |
495 | ||
496 | static int bus_socket_read_auth(sd_bus *b) { | |
497 | struct msghdr mh; | |
498 | struct iovec iov; | |
499 | size_t n; | |
500 | ssize_t k; | |
501 | int r; | |
502 | void *p; | |
503 | union { | |
504 | struct cmsghdr cmsghdr; | |
505 | uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) + | |
506 | CMSG_SPACE(sizeof(struct ucred)) + | |
507 | CMSG_SPACE(NAME_MAX)]; /*selinux label */ | |
508 | } control; | |
509 | struct cmsghdr *cmsg; | |
510 | bool handle_cmsg = false; | |
511 | ||
512 | assert(b); | |
513 | assert(b->state == BUS_AUTHENTICATING); | |
514 | ||
515 | r = bus_socket_auth_verify(b); | |
516 | if (r != 0) | |
517 | return r; | |
518 | ||
519 | n = MAX(256u, b->rbuffer_size * 2); | |
520 | ||
521 | if (n > BUS_AUTH_SIZE_MAX) | |
522 | n = BUS_AUTH_SIZE_MAX; | |
523 | ||
524 | if (b->rbuffer_size >= n) | |
525 | return -ENOBUFS; | |
526 | ||
527 | p = realloc(b->rbuffer, n); | |
528 | if (!p) | |
529 | return -ENOMEM; | |
530 | ||
531 | b->rbuffer = p; | |
532 | ||
533 | zero(iov); | |
534 | iov.iov_base = (uint8_t*) b->rbuffer + b->rbuffer_size; | |
535 | iov.iov_len = n - b->rbuffer_size; | |
536 | ||
537 | if (b->prefer_readv) | |
538 | k = readv(b->input_fd, &iov, 1); | |
539 | else { | |
540 | zero(mh); | |
541 | mh.msg_iov = &iov; | |
542 | mh.msg_iovlen = 1; | |
543 | mh.msg_control = &control; | |
544 | mh.msg_controllen = sizeof(control); | |
545 | ||
546 | k = recvmsg(b->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC); | |
547 | if (k < 0 && errno == ENOTSOCK) { | |
548 | b->prefer_readv = true; | |
549 | k = readv(b->input_fd, &iov, 1); | |
550 | } else | |
551 | handle_cmsg = true; | |
552 | } | |
553 | if (k < 0) | |
554 | return errno == EAGAIN ? 0 : -errno; | |
555 | if (k == 0) | |
556 | return -ECONNRESET; | |
557 | ||
558 | b->rbuffer_size += k; | |
559 | ||
560 | if (handle_cmsg) { | |
561 | for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) { | |
562 | if (cmsg->cmsg_level == SOL_SOCKET && | |
563 | cmsg->cmsg_type == SCM_RIGHTS) { | |
564 | int j; | |
565 | ||
566 | /* Whut? We received fds during the auth | |
567 | * protocol? Somebody is playing games with | |
568 | * us. Close them all, and fail */ | |
569 | j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); | |
570 | close_many((int*) CMSG_DATA(cmsg), j); | |
571 | return -EIO; | |
572 | ||
573 | } else if (cmsg->cmsg_level == SOL_SOCKET && | |
574 | cmsg->cmsg_type == SCM_CREDENTIALS && | |
575 | cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) { | |
576 | ||
577 | /* Ignore bogus data, which we might | |
578 | * get on socketpair() sockets */ | |
579 | if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) { | |
580 | memcpy(&b->ucred, CMSG_DATA(cmsg), sizeof(struct ucred)); | |
581 | b->ucred_valid = true; | |
582 | } | |
583 | ||
584 | } else if (cmsg->cmsg_level == SOL_SOCKET && | |
585 | cmsg->cmsg_type == SCM_SECURITY) { | |
586 | ||
587 | size_t l; | |
588 | ||
589 | l = cmsg->cmsg_len - CMSG_LEN(0); | |
590 | if (l > 0) { | |
591 | memcpy(&b->label, CMSG_DATA(cmsg), l); | |
592 | b->label[l] = 0; | |
593 | } | |
594 | } | |
595 | } | |
596 | } | |
597 | ||
598 | r = bus_socket_auth_verify(b); | |
599 | if (r != 0) | |
600 | return r; | |
601 | ||
602 | return 1; | |
603 | } | |
604 | ||
605 | void bus_socket_setup(sd_bus *b) { | |
606 | int enable; | |
607 | ||
608 | assert(b); | |
609 | ||
610 | /* Enable SO_PASSCRED + SO_PASSEC. We try this on any | |
611 | * socket, just in case. */ | |
612 | enable = !b->bus_client; | |
613 | (void)setsockopt(b->input_fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable)); | |
614 | ||
615 | enable = !b->bus_client && (b->attach_flags & KDBUS_ATTACH_SECLABEL); | |
616 | (void)setsockopt(b->input_fd, SOL_SOCKET, SO_PASSSEC, &enable, sizeof(enable)); | |
617 | ||
618 | /* Increase the buffers to 8 MB */ | |
619 | fd_inc_rcvbuf(b->input_fd, SNDBUF_SIZE); | |
620 | fd_inc_sndbuf(b->output_fd, SNDBUF_SIZE); | |
621 | ||
622 | b->is_kernel = false; | |
623 | b->message_version = 1; | |
624 | b->message_endian = 0; | |
625 | } | |
626 | ||
627 | static void bus_get_peercred(sd_bus *b) { | |
628 | assert(b); | |
629 | ||
630 | /* Get the peer for socketpair() sockets */ | |
631 | b->ucred_valid = getpeercred(b->input_fd, &b->ucred) >= 0; | |
632 | } | |
633 | ||
634 | static int bus_socket_start_auth_client(sd_bus *b) { | |
635 | size_t l; | |
636 | const char *auth_suffix, *auth_prefix; | |
637 | ||
638 | assert(b); | |
639 | ||
640 | if (b->anonymous_auth) { | |
641 | auth_prefix = "\0AUTH ANONYMOUS "; | |
642 | ||
643 | /* For ANONYMOUS auth we send some arbitrary "trace" string */ | |
644 | l = 9; | |
645 | b->auth_buffer = hexmem("anonymous", l); | |
646 | } else { | |
647 | char text[20 + 1]; /* enough space for a 64bit integer plus NUL */ | |
648 | ||
649 | auth_prefix = "\0AUTH EXTERNAL "; | |
650 | ||
651 | snprintf(text, sizeof(text), UID_FMT, geteuid()); | |
652 | char_array_0(text); | |
653 | ||
654 | l = strlen(text); | |
655 | b->auth_buffer = hexmem(text, l); | |
656 | } | |
657 | ||
658 | if (!b->auth_buffer) | |
659 | return -ENOMEM; | |
660 | ||
661 | if (b->hello_flags & KDBUS_HELLO_ACCEPT_FD) | |
662 | auth_suffix = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n"; | |
663 | else | |
664 | auth_suffix = "\r\nBEGIN\r\n"; | |
665 | ||
666 | b->auth_iovec[0].iov_base = (void*) auth_prefix; | |
667 | b->auth_iovec[0].iov_len = 1 + strlen(auth_prefix + 1); | |
668 | b->auth_iovec[1].iov_base = (void*) b->auth_buffer; | |
669 | b->auth_iovec[1].iov_len = l * 2; | |
670 | b->auth_iovec[2].iov_base = (void*) auth_suffix; | |
671 | b->auth_iovec[2].iov_len = strlen(auth_suffix); | |
672 | ||
673 | return bus_socket_write_auth(b); | |
674 | } | |
675 | ||
676 | int bus_socket_start_auth(sd_bus *b) { | |
677 | assert(b); | |
678 | ||
679 | bus_get_peercred(b); | |
680 | ||
681 | b->state = BUS_AUTHENTICATING; | |
682 | b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_DEFAULT_TIMEOUT; | |
683 | ||
684 | if (sd_is_socket(b->input_fd, AF_UNIX, 0, 0) <= 0) | |
685 | b->hello_flags &= ~KDBUS_HELLO_ACCEPT_FD; | |
686 | ||
687 | if (b->output_fd != b->input_fd) | |
688 | if (sd_is_socket(b->output_fd, AF_UNIX, 0, 0) <= 0) | |
689 | b->hello_flags &= ~KDBUS_HELLO_ACCEPT_FD; | |
690 | ||
691 | if (b->is_server) | |
692 | return bus_socket_read_auth(b); | |
693 | else | |
694 | return bus_socket_start_auth_client(b); | |
695 | } | |
696 | ||
697 | int bus_socket_connect(sd_bus *b) { | |
698 | int r; | |
699 | ||
700 | assert(b); | |
701 | assert(b->input_fd < 0); | |
702 | assert(b->output_fd < 0); | |
703 | assert(b->sockaddr.sa.sa_family != AF_UNSPEC); | |
704 | ||
705 | b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); | |
706 | if (b->input_fd < 0) | |
707 | return -errno; | |
708 | ||
709 | b->output_fd = b->input_fd; | |
710 | ||
711 | bus_socket_setup(b); | |
712 | ||
713 | r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size); | |
714 | if (r < 0) { | |
715 | if (errno == EINPROGRESS) | |
716 | return 1; | |
717 | ||
718 | return -errno; | |
719 | } | |
720 | ||
721 | return bus_socket_start_auth(b); | |
722 | } | |
723 | ||
724 | int bus_socket_exec(sd_bus *b) { | |
725 | int s[2], r; | |
726 | pid_t pid; | |
727 | ||
728 | assert(b); | |
729 | assert(b->input_fd < 0); | |
730 | assert(b->output_fd < 0); | |
731 | assert(b->exec_path); | |
732 | ||
733 | r = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s); | |
734 | if (r < 0) | |
735 | return -errno; | |
736 | ||
737 | pid = fork(); | |
738 | if (pid < 0) { | |
739 | safe_close_pair(s); | |
740 | return -errno; | |
741 | } | |
742 | if (pid == 0) { | |
743 | /* Child */ | |
744 | ||
745 | reset_all_signal_handlers(); | |
746 | ||
747 | close_all_fds(s+1, 1); | |
748 | ||
749 | assert_se(dup3(s[1], STDIN_FILENO, 0) == STDIN_FILENO); | |
750 | assert_se(dup3(s[1], STDOUT_FILENO, 0) == STDOUT_FILENO); | |
751 | ||
752 | if (s[1] != STDIN_FILENO && s[1] != STDOUT_FILENO) | |
753 | safe_close(s[1]); | |
754 | ||
755 | fd_cloexec(STDIN_FILENO, false); | |
756 | fd_cloexec(STDOUT_FILENO, false); | |
757 | fd_nonblock(STDIN_FILENO, false); | |
758 | fd_nonblock(STDOUT_FILENO, false); | |
759 | ||
760 | if (b->exec_argv) | |
761 | execvp(b->exec_path, b->exec_argv); | |
762 | else { | |
763 | const char *argv[] = { b->exec_path, NULL }; | |
764 | execvp(b->exec_path, (char**) argv); | |
765 | } | |
766 | ||
767 | _exit(EXIT_FAILURE); | |
768 | } | |
769 | ||
770 | safe_close(s[1]); | |
771 | b->output_fd = b->input_fd = s[0]; | |
772 | ||
773 | bus_socket_setup(b); | |
774 | ||
775 | return bus_socket_start_auth(b); | |
776 | } | |
777 | ||
778 | int bus_socket_take_fd(sd_bus *b) { | |
779 | assert(b); | |
780 | ||
781 | bus_socket_setup(b); | |
782 | ||
783 | return bus_socket_start_auth(b); | |
784 | } | |
785 | ||
786 | int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) { | |
787 | struct iovec *iov; | |
788 | ssize_t k; | |
789 | size_t n; | |
790 | unsigned j; | |
791 | int r; | |
792 | ||
793 | assert(bus); | |
794 | assert(m); | |
795 | assert(idx); | |
796 | assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO); | |
797 | ||
798 | if (*idx >= BUS_MESSAGE_SIZE(m)) | |
799 | return 0; | |
800 | ||
801 | r = bus_message_setup_iovec(m); | |
802 | if (r < 0) | |
803 | return r; | |
804 | ||
805 | n = m->n_iovec * sizeof(struct iovec); | |
806 | iov = alloca(n); | |
807 | memcpy(iov, m->iovec, n); | |
808 | ||
809 | j = 0; | |
810 | iovec_advance(iov, &j, *idx); | |
811 | ||
812 | if (bus->prefer_writev) | |
813 | k = writev(bus->output_fd, iov, m->n_iovec); | |
814 | else { | |
815 | struct msghdr mh; | |
816 | zero(mh); | |
817 | ||
818 | if (m->n_fds > 0) { | |
819 | struct cmsghdr *control; | |
820 | control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds)); | |
821 | ||
822 | mh.msg_control = control; | |
823 | control->cmsg_level = SOL_SOCKET; | |
824 | control->cmsg_type = SCM_RIGHTS; | |
825 | mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds); | |
826 | memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds); | |
827 | } | |
828 | ||
829 | mh.msg_iov = iov; | |
830 | mh.msg_iovlen = m->n_iovec; | |
831 | ||
832 | k = sendmsg(bus->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL); | |
833 | if (k < 0 && errno == ENOTSOCK) { | |
834 | bus->prefer_writev = true; | |
835 | k = writev(bus->output_fd, iov, m->n_iovec); | |
836 | } | |
837 | } | |
838 | ||
839 | if (k < 0) | |
840 | return errno == EAGAIN ? 0 : -errno; | |
841 | ||
842 | *idx += (size_t) k; | |
843 | return 1; | |
844 | } | |
845 | ||
846 | static int bus_socket_read_message_need(sd_bus *bus, size_t *need) { | |
847 | uint32_t a, b; | |
848 | uint8_t e; | |
849 | uint64_t sum; | |
850 | ||
851 | assert(bus); | |
852 | assert(need); | |
853 | assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO); | |
854 | ||
855 | if (bus->rbuffer_size < sizeof(struct bus_header)) { | |
856 | *need = sizeof(struct bus_header) + 8; | |
857 | ||
858 | /* Minimum message size: | |
859 | * | |
860 | * Header + | |
861 | * | |
862 | * Method Call: +2 string headers | |
863 | * Signal: +3 string headers | |
864 | * Method Error: +1 string headers | |
865 | * +1 uint32 headers | |
866 | * Method Reply: +1 uint32 headers | |
867 | * | |
868 | * A string header is at least 9 bytes | |
869 | * A uint32 header is at least 8 bytes | |
870 | * | |
871 | * Hence the minimum message size of a valid message | |
872 | * is header + 8 bytes */ | |
873 | ||
874 | return 0; | |
875 | } | |
876 | ||
877 | a = ((const uint32_t*) bus->rbuffer)[1]; | |
878 | b = ((const uint32_t*) bus->rbuffer)[3]; | |
879 | ||
880 | e = ((const uint8_t*) bus->rbuffer)[0]; | |
881 | if (e == BUS_LITTLE_ENDIAN) { | |
882 | a = le32toh(a); | |
883 | b = le32toh(b); | |
884 | } else if (e == BUS_BIG_ENDIAN) { | |
885 | a = be32toh(a); | |
886 | b = be32toh(b); | |
887 | } else | |
888 | return -EBADMSG; | |
889 | ||
890 | sum = (uint64_t) sizeof(struct bus_header) + (uint64_t) ALIGN_TO(b, 8) + (uint64_t) a; | |
891 | if (sum >= BUS_MESSAGE_SIZE_MAX) | |
892 | return -ENOBUFS; | |
893 | ||
894 | *need = (size_t) sum; | |
895 | return 0; | |
896 | } | |
897 | ||
898 | static int bus_socket_make_message(sd_bus *bus, size_t size) { | |
899 | sd_bus_message *t; | |
900 | void *b; | |
901 | int r; | |
902 | ||
903 | assert(bus); | |
904 | assert(bus->rbuffer_size >= size); | |
905 | assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO); | |
906 | ||
907 | r = bus_rqueue_make_room(bus); | |
908 | if (r < 0) | |
909 | return r; | |
910 | ||
911 | if (bus->rbuffer_size > size) { | |
912 | b = memdup((const uint8_t*) bus->rbuffer + size, | |
913 | bus->rbuffer_size - size); | |
914 | if (!b) | |
915 | return -ENOMEM; | |
916 | } else | |
917 | b = NULL; | |
918 | ||
919 | r = bus_message_from_malloc(bus, | |
920 | bus->rbuffer, size, | |
921 | bus->fds, bus->n_fds, | |
922 | !bus->bus_client && bus->ucred_valid ? &bus->ucred : NULL, | |
923 | !bus->bus_client && bus->label[0] ? bus->label : NULL, | |
924 | &t); | |
925 | if (r < 0) { | |
926 | free(b); | |
927 | return r; | |
928 | } | |
929 | ||
930 | bus->rbuffer = b; | |
931 | bus->rbuffer_size -= size; | |
932 | ||
933 | bus->fds = NULL; | |
934 | bus->n_fds = 0; | |
935 | ||
936 | bus->rqueue[bus->rqueue_size++] = t; | |
937 | ||
938 | return 1; | |
939 | } | |
940 | ||
941 | int bus_socket_read_message(sd_bus *bus) { | |
942 | struct msghdr mh; | |
943 | struct iovec iov; | |
944 | ssize_t k; | |
945 | size_t need; | |
946 | int r; | |
947 | void *b; | |
948 | union { | |
949 | struct cmsghdr cmsghdr; | |
950 | uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) + | |
951 | CMSG_SPACE(sizeof(struct ucred)) + | |
952 | CMSG_SPACE(NAME_MAX)]; /*selinux label */ | |
953 | } control; | |
954 | struct cmsghdr *cmsg; | |
955 | bool handle_cmsg = false; | |
956 | ||
957 | assert(bus); | |
958 | assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO); | |
959 | ||
960 | r = bus_socket_read_message_need(bus, &need); | |
961 | if (r < 0) | |
962 | return r; | |
963 | ||
964 | if (bus->rbuffer_size >= need) | |
965 | return bus_socket_make_message(bus, need); | |
966 | ||
967 | b = realloc(bus->rbuffer, need); | |
968 | if (!b) | |
969 | return -ENOMEM; | |
970 | ||
971 | bus->rbuffer = b; | |
972 | ||
973 | zero(iov); | |
974 | iov.iov_base = (uint8_t*) bus->rbuffer + bus->rbuffer_size; | |
975 | iov.iov_len = need - bus->rbuffer_size; | |
976 | ||
977 | if (bus->prefer_readv) | |
978 | k = readv(bus->input_fd, &iov, 1); | |
979 | else { | |
980 | zero(mh); | |
981 | mh.msg_iov = &iov; | |
982 | mh.msg_iovlen = 1; | |
983 | mh.msg_control = &control; | |
984 | mh.msg_controllen = sizeof(control); | |
985 | ||
986 | k = recvmsg(bus->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC); | |
987 | if (k < 0 && errno == ENOTSOCK) { | |
988 | bus->prefer_readv = true; | |
989 | k = readv(bus->input_fd, &iov, 1); | |
990 | } else | |
991 | handle_cmsg = true; | |
992 | } | |
993 | if (k < 0) | |
994 | return errno == EAGAIN ? 0 : -errno; | |
995 | if (k == 0) | |
996 | return -ECONNRESET; | |
997 | ||
998 | bus->rbuffer_size += k; | |
999 | ||
1000 | if (handle_cmsg) { | |
1001 | for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) { | |
1002 | if (cmsg->cmsg_level == SOL_SOCKET && | |
1003 | cmsg->cmsg_type == SCM_RIGHTS) { | |
1004 | int n, *f; | |
1005 | ||
1006 | n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); | |
1007 | ||
1008 | if (!bus->can_fds) { | |
1009 | /* Whut? We received fds but this | |
1010 | * isn't actually enabled? Close them, | |
1011 | * and fail */ | |
1012 | ||
1013 | close_many((int*) CMSG_DATA(cmsg), n); | |
1014 | return -EIO; | |
1015 | } | |
1016 | ||
1017 | f = realloc(bus->fds, sizeof(int) + (bus->n_fds + n)); | |
1018 | if (!f) { | |
1019 | close_many((int*) CMSG_DATA(cmsg), n); | |
1020 | return -ENOMEM; | |
1021 | } | |
1022 | ||
1023 | memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int)); | |
1024 | bus->fds = f; | |
1025 | bus->n_fds += n; | |
1026 | } else if (cmsg->cmsg_level == SOL_SOCKET && | |
1027 | cmsg->cmsg_type == SCM_CREDENTIALS && | |
1028 | cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) { | |
1029 | ||
1030 | /* Ignore bogus data, which we might | |
1031 | * get on socketpair() sockets */ | |
1032 | if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) { | |
1033 | memcpy(&bus->ucred, CMSG_DATA(cmsg), sizeof(struct ucred)); | |
1034 | bus->ucred_valid = true; | |
1035 | } | |
1036 | ||
1037 | } else if (cmsg->cmsg_level == SOL_SOCKET && | |
1038 | cmsg->cmsg_type == SCM_SECURITY) { | |
1039 | ||
1040 | size_t l; | |
1041 | l = cmsg->cmsg_len - CMSG_LEN(0); | |
1042 | if (l > 0) { | |
1043 | memcpy(&bus->label, CMSG_DATA(cmsg), l); | |
1044 | bus->label[l] = 0; | |
1045 | } | |
1046 | } | |
1047 | } | |
1048 | } | |
1049 | ||
1050 | r = bus_socket_read_message_need(bus, &need); | |
1051 | if (r < 0) | |
1052 | return r; | |
1053 | ||
1054 | if (bus->rbuffer_size >= need) | |
1055 | return bus_socket_make_message(bus, need); | |
1056 | ||
1057 | return 1; | |
1058 | } | |
1059 | ||
1060 | int bus_socket_process_opening(sd_bus *b) { | |
1061 | int error = 0; | |
1062 | socklen_t slen = sizeof(error); | |
1063 | struct pollfd p = { | |
1064 | .fd = b->output_fd, | |
1065 | .events = POLLOUT, | |
1066 | }; | |
1067 | int r; | |
1068 | ||
1069 | assert(b->state == BUS_OPENING); | |
1070 | ||
1071 | r = poll(&p, 1, 0); | |
1072 | if (r < 0) | |
1073 | return -errno; | |
1074 | ||
1075 | if (!(p.revents & (POLLOUT|POLLERR|POLLHUP))) | |
1076 | return 0; | |
1077 | ||
1078 | r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen); | |
1079 | if (r < 0) | |
1080 | b->last_connect_error = errno; | |
1081 | else if (error != 0) | |
1082 | b->last_connect_error = error; | |
1083 | else if (p.revents & (POLLERR|POLLHUP)) | |
1084 | b->last_connect_error = ECONNREFUSED; | |
1085 | else | |
1086 | return bus_socket_start_auth(b); | |
1087 | ||
1088 | return bus_next_address(b); | |
1089 | } | |
1090 | ||
1091 | int bus_socket_process_authenticating(sd_bus *b) { | |
1092 | int r; | |
1093 | ||
1094 | assert(b); | |
1095 | assert(b->state == BUS_AUTHENTICATING); | |
1096 | ||
1097 | if (now(CLOCK_MONOTONIC) >= b->auth_timeout) | |
1098 | return -ETIMEDOUT; | |
1099 | ||
1100 | r = bus_socket_write_auth(b); | |
1101 | if (r != 0) | |
1102 | return r; | |
1103 | ||
1104 | return bus_socket_read_auth(b); | |
1105 | } |