Merge branch 'refs/heads/t/ubsan'
[paraslash.git] / command.c
1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file command.c Client authentication and server commands. */
4
5 #include <netinet/in.h>
6 #include <sys/socket.h>
7 #include <regex.h>
8 #include <signal.h>
9 #include <arpa/inet.h>
10 #include <netdb.h>
11 #include <lopsub.h>
12
13 #include "server.lsg.h"
14 #include "para.h"
15 #include "error.h"
16 #include "lsu.h"
17 #include "crypt.h"
18 #include "sideband.h"
19 #include "command.h"
20 #include "string.h"
21 #include "afh.h"
22 #include "net.h"
23 #include "server.h"
24 #include "list.h"
25 #include "send.h"
26 #include "sched.h"
27 #include "vss.h"
28 #include "daemon.h"
29 #include "fd.h"
30 #include "ipc.h"
31 #include "server_cmd.lsg.h"
32 #include "user_list.h"
33 #include "signal.h"
34 #include "version.h"
35
36 #define SERVER_CMD_AUX_INFO(_arg) _arg,
37 static const unsigned server_command_perms[] = {LSG_SERVER_CMD_AUX_INFOS};
38 #undef SERVER_CMD_AUX_INFO
39 #define SERVER_CMD_AUX_INFO(_arg) #_arg,
40 static const char * const server_command_perms_txt[] = {LSG_SERVER_CMD_AUX_INFOS};
41 #undef SERVER_CMD_AUX_INFO
42
43 /** Commands including options must be shorter than this. */
44 #define MAX_COMMAND_LEN 32768
45
46 extern int mmd_mutex;
47 extern struct misc_meta_data *mmd;
48 int send_afs_status(struct command_context *cc, int parser_friendly);
49 static bool subcmd_should_die;
50
51 static void command_handler_sighandler(int s)
52 {
53 if (s != SIGTERM)
54 return;
55 PARA_EMERG_LOG("terminating on signal %d\n", SIGTERM);
56 subcmd_should_die = true;
57 }
58
59 /*
60 * Compute human readable vss status text.
61 *
62 * We can't call vss_playing() and friends here because those functions read
63 * the flags from the primary mmd structure, so calling them from command
64 * handler context would require to take the mmd lock. At the time the function
65 * is called we already took a copy of the mmd structure and want to use the
66 * flags value of the copy for computing the vss status text.
67 */
68 static char *vss_status_tohuman(unsigned int flags)
69 {
70 if (flags & VSS_PLAYING)
71 return para_strdup("playing");
72 if (flags & VSS_NEXT)
73 return para_strdup("stopped");
74 return para_strdup("paused");
75 }
76
77 /*
78 * Never returns NULL.
79 */
80 static char *vss_get_status_flags(unsigned int flags)
81 {
82 char *msg = para_malloc(5 * sizeof(char));
83
84 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
85 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
86 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
87 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
88 msg[4] = '\0';
89 return msg;
90 }
91
92 static unsigned get_status(struct misc_meta_data *nmmd, bool parser_friendly,
93 char **result)
94 {
95 char *status, *flags; /* vss status info */
96 /* nobody updates our version of "now" */
97 long offset = (nmmd->offset + 500) / 1000;
98 struct timeval current_time;
99 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
100
101 /* report real status */
102 status = vss_status_tohuman(nmmd->vss_status_flags);
103 flags = vss_get_status_flags(nmmd->vss_status_flags);
104 clock_get_realtime(&current_time);
105 /*
106 * The calls to WRITE_STATUS_ITEM() below never fail because
107 * b->max_size is zero (unlimited), see \ref para_printf(). However,
108 * clang is not smart enough to prove this and complains nevertheless.
109 * Casting the return value to void silences clang.
110 */
111 (void)WRITE_STATUS_ITEM(&b, SI_status, "%s\n", status);
112 (void)WRITE_STATUS_ITEM(&b, SI_status_flags, "%s\n", flags);
113 (void)WRITE_STATUS_ITEM(&b, SI_offset, "%li\n", offset);
114 (void)WRITE_STATUS_ITEM(&b, SI_afs_mode, "%s\n", mmd->afs_mode_string);
115 (void)WRITE_STATUS_ITEM(&b, SI_stream_start, "%lu.%lu\n",
116 (long unsigned)nmmd->stream_start.tv_sec,
117 (long unsigned)nmmd->stream_start.tv_usec);
118 (void)WRITE_STATUS_ITEM(&b, SI_current_time, "%lu.%lu\n",
119 (long unsigned)current_time.tv_sec,
120 (long unsigned)current_time.tv_usec);
121 free(flags);
122 free(status);
123 *result = b.buf;
124 return b.offset;
125 }
126
127 /**
128 * Send a sideband packet through a blocking file descriptor.
129 *
130 * \param scc fd and crypto keys.
131 * \param buf The buffer to send.
132 * \param numbytes The size of \a buf.
133 * \param band The sideband designator of this packet.
134 * \param dont_free If true, never deallocate \a buf.
135 *
136 * The nonblock flag must be disabled for the file descriptor given by \a scc.
137 *
138 * Stream cipher encryption is automatically activated if necessary via the
139 * sideband transformation, depending on the value of \a band.
140 *
141 * \return Standard.
142 *
143 * \sa \ref send_sb_va().
144 */
145 int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
146 int band, bool dont_free)
147 {
148 int ret;
149 struct sb_context *sbc;
150 struct iovec iov[2];
151 sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
152 struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
153
154 sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
155 do {
156 ret = sb_get_send_buffers(sbc, iov);
157 ret = xwritev(scc->fd, iov, ret);
158 if (ret < 0)
159 goto fail;
160 } while (sb_sent(sbc, ret) == false);
161 return 1;
162 fail:
163 sb_free(sbc);
164 return ret;
165 }
166
167 /**
168 * Create a variable sized buffer and send it as a sideband packet.
169 *
170 * \param scc Passed to \ref send_sb.
171 * \param band See \ref send_sb.
172 * \param fmt The format string.
173 *
174 * \return The return value of the underlying call to \ref send_sb.
175 */
176 __printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
177 const char *fmt, ...)
178 {
179 va_list ap;
180 char *msg;
181 int ret;
182
183 va_start(ap, fmt);
184 ret = xvasprintf(&msg, fmt, ap);
185 va_end(ap);
186 return send_sb(scc, msg, ret, band, false);
187 }
188
189 /**
190 * Send an error message to a client.
191 *
192 * \param cc Client info.
193 * \param err The (positive) error code.
194 *
195 * \return The return value of the underlying call to send_sb_va().
196 */
197 int send_strerror(struct command_context *cc, int err)
198 {
199 return send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err));
200 }
201
202 /**
203 * Send an error context to a client,
204 *
205 * \param cc Client info.
206 * \param errctx The error context string.
207 *
208 * \return The return value of the underlying call to send_sb_va().
209 *
210 * This function frees the error context string after it was sent.
211 */
212 int send_errctx(struct command_context *cc, char *errctx)
213 {
214 int ret;
215
216 if (!errctx)
217 return 0;
218 ret = send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", errctx);
219 free(errctx);
220 return ret;
221 }
222
223 static int check_sender_args(struct command_context *cc,
224 struct lls_parse_result *lpr, struct sender_command_data *scd)
225 {
226 int i, ret;
227 const char * const subcmds[] = {SENDER_SUBCOMMANDS};
228 const char *arg;
229 char *errctx;
230 unsigned num_inputs = lls_num_inputs(lpr);
231
232 scd->sender_num = -1;
233 ret = lls(lls_check_arg_count(lpr, 2, INT_MAX, &errctx));
234 if (ret < 0) {
235 send_errctx(cc, errctx);
236 return ret;
237 }
238 arg = lls_input(0, lpr);
239 FOR_EACH_SENDER(i)
240 if (strcmp(senders[i]->name, arg) == 0)
241 break;
242 if (!senders[i])
243 return -E_COMMAND_SYNTAX;
244 scd->sender_num = i;
245 arg = lls_input(1, lpr);
246 for (i = 0; i < NUM_SENDER_CMDS; i++)
247 if (!strcmp(subcmds[i], arg))
248 break;
249 if (i == NUM_SENDER_CMDS)
250 return -E_COMMAND_SYNTAX;
251 scd->cmd_num = i;
252 if (!senders[scd->sender_num]->client_cmds[scd->cmd_num])
253 return -E_SENDER_CMD;
254 switch (scd->cmd_num) {
255 case SENDER_on:
256 case SENDER_off:
257 if (num_inputs != 2)
258 return -E_COMMAND_SYNTAX;
259 break;
260 case SENDER_deny:
261 case SENDER_allow:
262 if (num_inputs != 3 || parse_cidr(lls_input(2, lpr), scd->host,
263 sizeof(scd->host), &scd->netmask) == NULL)
264 return -E_COMMAND_SYNTAX;
265 break;
266 case SENDER_add:
267 case SENDER_delete:
268 if (num_inputs != 3)
269 return -E_COMMAND_SYNTAX;
270 return parse_fec_url(lls_input(2, lpr), scd);
271 default:
272 return -E_COMMAND_SYNTAX;
273 }
274 return 1;
275 }
276
277 /**
278 * Receive a sideband packet from a blocking file descriptor.
279 *
280 * \param scc fd and crypto keys.
281 * \param expected_band The expected band designator.
282 * \param max_size Passed to \ref sb_new_recv().
283 * \param result Body of the sideband packet is returned here.
284 *
285 * If \a expected_band is not \p SBD_ANY, the band designator of the received
286 * sideband packet is compared to \a expected_band and a mismatch is considered
287 * an error.
288 *
289 * \return Standard.
290 */
291 int recv_sb(struct stream_cipher_context *scc,
292 enum sb_designator expected_band,
293 size_t max_size, struct iovec *result)
294 {
295 int ret;
296 struct sb_context *sbc;
297 struct iovec iov;
298 struct sb_buffer sbb;
299 sb_transformation trafo;
300
301 trafo = expected_band != SBD_ANY && expected_band < SBD_PROCEED?
302 NULL : sc_trafo;
303 sbc = sb_new_recv(max_size, trafo, scc->recv);
304 for (;;) {
305 sb_get_recv_buffer(sbc, &iov);
306 ret = recv_bin_buffer(scc->fd, iov.iov_base, iov.iov_len);
307 if (ret == 0)
308 ret = -E_EOF;
309 if (ret < 0)
310 goto fail;
311 ret = sb_received(sbc, ret, &sbb);
312 if (ret < 0)
313 goto fail;
314 if (ret > 0)
315 break;
316 }
317 ret = -E_BAD_BAND;
318 if (expected_band != SBD_ANY && sbb.band != expected_band)
319 goto fail;
320 *result = sbb.iov;
321 return 1;
322 fail:
323 sb_free(sbc);
324 return ret;
325 }
326
327 static int com_sender(struct command_context *cc, struct lls_parse_result *lpr)
328 {
329 int i, ret = 0;
330 char *msg = NULL;
331 struct sender_command_data scd;
332
333 if (lls_num_inputs(lpr) == 0) {
334 FOR_EACH_SENDER(i) {
335 char *tmp;
336 ret = xasprintf(&tmp, "%s%s\n", msg? msg : "",
337 senders[i]->name);
338 free(msg);
339 msg = tmp;
340 }
341 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
342 }
343 ret = check_sender_args(cc, lpr, &scd);
344 if (ret < 0) {
345 if (scd.sender_num < 0)
346 return ret;
347 if (strcmp(lls_input(1, lpr), "status") == 0)
348 msg = senders[scd.sender_num]->status();
349 else
350 msg = senders[scd.sender_num]->help();
351 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
352 }
353
354 switch (scd.cmd_num) {
355 case SENDER_add:
356 case SENDER_delete:
357 assert(senders[scd.sender_num]->resolve_target);
358 ret = senders[scd.sender_num]->resolve_target(lls_input(2, lpr),
359 &scd);
360 if (ret < 0)
361 return ret;
362 }
363
364 for (i = 0; i < 10; i++) {
365 mutex_lock(mmd_mutex);
366 if (mmd->sender_cmd_data.cmd_num >= 0) {
367 /* another sender command is active, retry in 100ms */
368 struct timespec ts = {.tv_nsec = 100 * 1000 * 1000};
369 mutex_unlock(mmd_mutex);
370 nanosleep(&ts, NULL);
371 continue;
372 }
373 mmd->sender_cmd_data = scd;
374 mutex_unlock(mmd_mutex);
375 break;
376 }
377 return (i < 10)? 1 : -E_LOCK;
378 }
379 EXPORT_SERVER_CMD_HANDLER(sender);
380
381 static int com_si(struct command_context *cc,
382 __a_unused struct lls_parse_result *lpr)
383 {
384 char *msg, *ut;
385 int ret;
386
387 ut = daemon_get_uptime_str(now);
388 mutex_lock(mmd_mutex);
389 ret = xasprintf(&msg,
390 "up: %s\nplayed: %u\n"
391 "server_pid: %d\n"
392 "afs_pid: %d\n"
393 "connections (active/accepted/total): %u/%u/%u\n"
394 "current loglevel: %s\n"
395 "supported audio formats: %s\n",
396 ut, mmd->num_played,
397 (int)getppid(),
398 (int)afs_pid,
399 mmd->active_connections,
400 mmd->num_commands,
401 mmd->num_connects,
402 ENUM_STRING_VAL(LOGLEVEL),
403 AUDIO_FORMAT_HANDLERS
404 );
405 mutex_unlock(mmd_mutex);
406 free(ut);
407 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
408 }
409 EXPORT_SERVER_CMD_HANDLER(si);
410
411 static int com_version(struct command_context *cc, struct lls_parse_result *lpr)
412 {
413 char *msg;
414 size_t len;
415
416 if (SERVER_CMD_OPT_GIVEN(VERSION, VERBOSE, lpr))
417 len = xasprintf(&msg, "%s", version_text("server"));
418 else
419 len = xasprintf(&msg, "%s\n", version_single_line("server"));
420 return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
421 }
422 EXPORT_SERVER_CMD_HANDLER(version);
423
424 /** These status items are cleared if no audio file is currently open. */
425 #define EMPTY_STATUS_ITEMS \
426 ITEM(path) \
427 ITEM(directory) \
428 ITEM(basename) \
429 ITEM(score) \
430 ITEM(attributes_bitmap) \
431 ITEM(attributes_txt) \
432 ITEM(hash) \
433 ITEM(image_id) \
434 ITEM(image_name) \
435 ITEM(lyrics_id) \
436 ITEM(lyrics_name) \
437 ITEM(bitrate) \
438 ITEM(format) \
439 ITEM(frequency) \
440 ITEM(channels) \
441 ITEM(duration) \
442 ITEM(seconds_total) \
443 ITEM(num_played) \
444 ITEM(last_played) \
445 ITEM(techinfo) \
446 ITEM(artist) \
447 ITEM(title) \
448 ITEM(year) \
449 ITEM(album) \
450 ITEM(comment) \
451 ITEM(mtime) \
452 ITEM(file_size) \
453 ITEM(chunk_time) \
454 ITEM(num_chunks) \
455 ITEM(amplification) \
456 ITEM(play_time) \
457
458 /*
459 * Create a set of audio-file related status items with empty values. These are
460 * written to stat clients when no audio file is open.
461 */
462 static unsigned empty_status_items(bool parser_friendly, char **result)
463 {
464 char *esi;
465 unsigned len;
466
467 if (parser_friendly)
468 len = xasprintf(&esi,
469 #define ITEM(x) "0004 %02x:\n"
470 EMPTY_STATUS_ITEMS
471 #undef ITEM
472 #define ITEM(x) , (unsigned) SI_ ## x
473 EMPTY_STATUS_ITEMS
474 #undef ITEM
475 );
476 else
477 len = xasprintf(&esi,
478 #define ITEM(x) "%s:\n"
479 EMPTY_STATUS_ITEMS
480 #undef ITEM
481 #define ITEM(x) ,status_item_list[SI_ ## x]
482 EMPTY_STATUS_ITEMS
483 #undef ITEM
484 );
485 *result = esi;
486 return len;
487 }
488 #undef EMPTY_STATUS_ITEMS
489
490 static int com_stat(struct command_context *cc, struct lls_parse_result *lpr)
491 {
492 int ret;
493 struct misc_meta_data tmp, *nmmd = &tmp;
494 char *s;
495 bool parser_friendly = SERVER_CMD_OPT_GIVEN(STAT, PARSER_FRIENDLY,
496 lpr) > 0;
497 uint32_t num = SERVER_CMD_UINT32_VAL(STAT, NUM, lpr);
498 const struct timespec ts = {.tv_sec = 50, .tv_nsec = 0};
499
500 para_sigaction(SIGINT, SIG_IGN);
501 para_sigaction(SIGUSR1, command_handler_sighandler);
502 para_sigaction(SIGTERM, command_handler_sighandler);
503 /*
504 * Simply checking subcmd_should_die is racy because a signal may
505 * arrive after the check but before the subsequent call to sleep(3).
506 * If this happens, sleep(3) would not be interrupted by the signal.
507 * To avoid this we block SIGTERM here and allow it to arrive only
508 * while we sleep.
509 */
510 para_block_signal(SIGTERM);
511 for (;;) {
512 sigset_t set;
513 /*
514 * Copy the mmd structure to minimize the time we hold the mmd
515 * lock.
516 */
517 mutex_lock(mmd_mutex);
518 *nmmd = *mmd;
519 mutex_unlock(mmd_mutex);
520 ret = get_status(nmmd, parser_friendly, &s);
521 ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
522 if (ret < 0)
523 goto out;
524 if (nmmd->vss_status_flags & VSS_NEXT) {
525 char *esi;
526 ret = empty_status_items(parser_friendly, &esi);
527 ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT, false);
528 if (ret < 0)
529 goto out;
530 } else
531 send_afs_status(cc, parser_friendly);
532 ret = 1;
533 if (num > 0 && !--num)
534 goto out;
535 sigemptyset(&set); /* empty set means: unblock all signals */
536 /*
537 * pselect(2) allows to atomically unblock signals, then go to
538 * sleep. Calling sigprocmask(2) followed by sleep(3) would
539 * open a race window similar to the one described above.
540 */
541 pselect(1, NULL, NULL, NULL, &ts, &set);
542 if (subcmd_should_die)
543 goto out;
544 ret = -E_SERVER_CRASH;
545 if (getppid() == 1)
546 goto out;
547 }
548 out:
549 return ret;
550 }
551 EXPORT_SERVER_CMD_HANDLER(stat);
552
553 static const char *aux_info_cb(unsigned cmd_num, bool verbose)
554 {
555 static char result[80];
556 unsigned perms = server_command_perms[cmd_num];
557
558 if (verbose) {
559 /* permissions: VSS_READ | VSS_WRITE */
560 sprintf(result, "permissions: %s",
561 server_command_perms_txt[cmd_num]);
562 } else {
563 result[0] = perms & AFS_READ? 'a' : '-';
564 result[1] = perms & AFS_WRITE? 'A' : '-';
565 result[2] = perms & VSS_READ? 'v' : '-';
566 result[3] = perms & VSS_WRITE? 'V' : '-';
567 result[4] = '\0';
568 }
569 return result;
570 }
571
572 static int com_help(struct command_context *cc, struct lls_parse_result *lpr)
573 {
574 char *buf;
575 int ret;
576 unsigned n;
577 bool long_help = SERVER_CMD_OPT_GIVEN(HELP, LONG, lpr);
578
579 lsu_com_help(long_help, lpr, server_cmd_suite, aux_info_cb, &buf, &n);
580 ret = send_sb(&cc->scc, buf, n, SBD_OUTPUT, false);
581 return ret;
582 }
583 EXPORT_SERVER_CMD_HANDLER(help);
584
585 static int com_hup(__a_unused struct command_context *cc,
586 __a_unused struct lls_parse_result *lpr)
587 {
588 kill(getppid(), SIGHUP);
589 return 1;
590 }
591 EXPORT_SERVER_CMD_HANDLER(hup);
592
593 static int com_term(__a_unused struct command_context *cc,
594 __a_unused struct lls_parse_result *lpr)
595 {
596 kill(getppid(), SIGTERM);
597 return 1;
598 }
599 EXPORT_SERVER_CMD_HANDLER(term);
600
601 static int com_play(__a_unused struct command_context *cc,
602 __a_unused struct lls_parse_result *lpr)
603 {
604 mutex_lock(mmd_mutex);
605 mmd->new_vss_status_flags |= VSS_PLAYING;
606 mmd->new_vss_status_flags &= ~VSS_NOMORE;
607 mutex_unlock(mmd_mutex);
608 return 1;
609 }
610 EXPORT_SERVER_CMD_HANDLER(play);
611
612 static int com_stop(__a_unused struct command_context *cc,
613 __a_unused struct lls_parse_result *lpr)
614 {
615 mutex_lock(mmd_mutex);
616 mmd->new_vss_status_flags &= ~VSS_PLAYING;
617 mmd->new_vss_status_flags &= ~VSS_REPOS;
618 mmd->new_vss_status_flags |= VSS_NEXT;
619 mutex_unlock(mmd_mutex);
620 return 1;
621 }
622 EXPORT_SERVER_CMD_HANDLER(stop);
623
624 static int com_pause(__a_unused struct command_context *cc,
625 __a_unused struct lls_parse_result *lpr)
626 {
627 mutex_lock(mmd_mutex);
628 if (!vss_paused() && !vss_stopped()) {
629 mmd->events++;
630 mmd->new_vss_status_flags &= ~VSS_PLAYING;
631 mmd->new_vss_status_flags &= ~VSS_NEXT;
632 }
633 mutex_unlock(mmd_mutex);
634 return 1;
635 }
636 EXPORT_SERVER_CMD_HANDLER(pause);
637
638 static int com_next(__a_unused struct command_context *cc,
639 __a_unused struct lls_parse_result *lpr)
640 {
641 mutex_lock(mmd_mutex);
642 mmd->events++;
643 mmd->new_vss_status_flags |= VSS_NEXT;
644 mutex_unlock(mmd_mutex);
645 return 1;
646 }
647 EXPORT_SERVER_CMD_HANDLER(next);
648
649 static int com_nomore(__a_unused struct command_context *cc,
650 __a_unused struct lls_parse_result *lpr)
651 {
652 mutex_lock(mmd_mutex);
653 if (vss_playing() || vss_paused())
654 mmd->new_vss_status_flags |= VSS_NOMORE;
655 mutex_unlock(mmd_mutex);
656 return 1;
657 }
658 EXPORT_SERVER_CMD_HANDLER(nomore);
659
660 static int com_ff(struct command_context *cc, struct lls_parse_result *lpr)
661 {
662 long promille;
663 int i, ret;
664 char c, *errctx;
665
666 ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
667 if (ret < 0) {
668 send_errctx(cc, errctx);
669 return ret;
670 }
671 ret = para_atoi32(lls_input(0, lpr), &i);
672 if (ret < 0) {
673 if (ret != -E_ATOI_JUNK_AT_END)
674 return ret;
675 /*
676 * Compatibility code to keep the historic syntax (ff 30-)
677 * working. This can be removed after 0.7.0.
678 */
679 ret = sscanf(lls_input(0, lpr), "%i%c", &i, &c);
680 if (ret <= 0)
681 return -E_COMMAND_SYNTAX;
682 if (ret > 1 && c == '-') {
683 PARA_WARNING_LOG("use of obsolete syntax\n");
684 i = -i;
685 }
686 }
687 mutex_lock(mmd_mutex);
688 ret = -E_NO_AUDIO_FILE;
689 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
690 goto out;
691 ret = 1;
692 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
693 /*
694 * We need this cast because without it the expression on the right
695 * hand side is of unsigned type.
696 */
697 promille += 1000 * i / (int)mmd->afd.afhi.seconds_total;
698 if (promille < 0)
699 promille = 0;
700 if (promille > 1000) {
701 mmd->new_vss_status_flags |= VSS_NEXT;
702 goto out;
703 }
704 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
705 mmd->new_vss_status_flags |= VSS_REPOS;
706 mmd->new_vss_status_flags &= ~VSS_NEXT;
707 mmd->events++;
708 out:
709 mutex_unlock(mmd_mutex);
710 return ret;
711 }
712 EXPORT_SERVER_CMD_HANDLER(ff);
713
714 static int com_jmp(struct command_context *cc, struct lls_parse_result *lpr)
715 {
716 int i, ret;
717 char *errctx;
718
719 ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
720 if (ret < 0) {
721 send_errctx(cc, errctx);
722 return ret;
723 }
724 if (sscanf(lls_input(0, lpr), "%d", &i) <= 0)
725 return -ERRNO_TO_PARA_ERROR(EINVAL);
726 if (i < 0 || i > 100)
727 return -ERRNO_TO_PARA_ERROR(EINVAL);
728 mutex_lock(mmd_mutex);
729 ret = -E_NO_AUDIO_FILE;
730 if (!mmd->afd.afhi.chunks_total)
731 goto out;
732 PARA_INFO_LOG("jumping to %d%%\n", i);
733 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50) / 100;
734 mmd->new_vss_status_flags |= VSS_REPOS;
735 mmd->new_vss_status_flags &= ~VSS_NEXT;
736 ret = 1;
737 mmd->events++;
738 out:
739 mutex_unlock(mmd_mutex);
740 return ret;
741 }
742 EXPORT_SERVER_CMD_HANDLER(jmp);
743
744 /* deprecated, does nothing */
745 static int com_tasks(__a_unused struct command_context *cc,
746 __a_unused struct lls_parse_result *lpr)
747 {
748 return 1;
749 }
750 EXPORT_SERVER_CMD_HANDLER(tasks);
751
752 static void reset_signals(void)
753 {
754 para_sigaction(SIGCHLD, SIG_IGN);
755 para_sigaction(SIGINT, SIG_DFL);
756 para_sigaction(SIGTERM, SIG_DFL);
757 para_sigaction(SIGHUP, SIG_DFL);
758 }
759
760 struct connection_features {
761 int dummy; /* none at the moment */
762 };
763
764 static int parse_auth_request(char *buf, int len, const struct user **u,
765 struct connection_features *cf)
766 {
767 int ret;
768 char *p, *username, **features = NULL;
769 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
770
771 *u = NULL;
772 memset(cf, 0, sizeof(*cf));
773 if (len < auth_rq_len + 2)
774 return -E_AUTH_REQUEST;
775 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
776 return -E_AUTH_REQUEST;
777 username = buf + auth_rq_len;
778 p = strchr(username, ' ');
779 if (p) {
780 int i;
781 if (p == username)
782 return -E_AUTH_REQUEST;
783 *p = '\0';
784 p++;
785 create_argv(p, ",", &features);
786 for (i = 0; features[i]; i++) {
787 if (strcmp(features[i], "sideband") == 0)
788 continue;
789 if (strcmp(features[i], "aes_ctr128") == 0)
790 continue;
791 else {
792 ret = -E_BAD_FEATURE;
793 goto out;
794 }
795 }
796 }
797 PARA_DEBUG_LOG("received auth request for user %s\n", username);
798 *u = user_list_lookup(username);
799 ret = 1;
800 out:
801 free_argv(features);
802 return ret;
803 }
804
805 #define HANDSHAKE_BUFSIZE 4096
806
807 static int run_command(struct command_context *cc, struct iovec *iov)
808 {
809 int ret, i, argc;
810 char *p, *end, **argv;
811 const struct lls_command *lcmd = NULL;
812 unsigned perms;
813 struct lls_parse_result *lpr;
814 char *errctx;
815
816 if (iov->iov_base == NULL || iov->iov_len == 0)
817 return -ERRNO_TO_PARA_ERROR(EINVAL);
818 p = iov->iov_base;
819 p[iov->iov_len - 1] = '\0'; /* just to be sure */
820
821 ret = lls(lls_lookup_subcmd(p, server_cmd_suite, &errctx));
822 if (ret < 0) {
823 send_errctx(cc, errctx);
824 return ret;
825 }
826 perms = server_command_perms[ret];
827 if ((perms & cc->u->perms) != perms)
828 return -E_PERM;
829 lcmd = lls_cmd(ret, server_cmd_suite);
830 end = iov->iov_base + iov->iov_len;
831 for (i = 0; p < end; i++)
832 p += strlen(p) + 1;
833 argc = i;
834 argv = para_malloc((argc + 1) * sizeof(char *));
835 for (i = 0, p = iov->iov_base; p < end; i++) {
836 argv[i] = para_strdup(p);
837 p += strlen(p) + 1;
838 }
839 argv[argc] = NULL;
840 PARA_NOTICE_LOG("calling com_%s() for user %s\n",
841 lls_command_name(lcmd), cc->u->name);
842 ret = lls(lls_parse(argc, argv, lcmd, &lpr, &errctx));
843 if (ret >= 0) {
844 const struct server_cmd_user_data *ud = lls_user_data(lcmd);
845 ret = ud->handler(cc, lpr);
846 lls_free_parse_result(lpr, lcmd);
847 } else
848 send_errctx(cc, errctx);
849 free_argv(argv);
850 mutex_lock(mmd_mutex);
851 mmd->num_commands++;
852 if (ret >= 0 && (perms & AFS_WRITE))
853 mmd->events++;
854 mutex_unlock(mmd_mutex);
855 return ret;
856 }
857
858 /**
859 * Perform user authentication and execute a command.
860 *
861 * \param fd The file descriptor to send output to.
862 *
863 * Whenever para_server accepts an incoming tcp connection on the port it
864 * listens on, it forks and the resulting child calls this function.
865 *
866 * An RSA-based challenge/response is used to authenticate the peer. If the
867 * authentication succeeds, a random session key is generated and sent back to
868 * the peer, encrypted with its RSA public key. From this point on, all
869 * transfers are encrypted with this session key using a stream cipher.
870 *
871 * Next it is checked if the peer supplied a valid server command or a command
872 * for the audio file selector. If yes, and if the user has sufficient
873 * permissions to execute this command, the function calls the corresponding
874 * command handler which performs argument checking and further processing.
875 *
876 * To cope with DOS attacks, a timer is set up right after the fork. If the
877 * connection was still not authenticated when the timeout expires, the child
878 * process is terminated.
879 *
880 * \return Standard.
881 *
882 * \sa alarm(2), \ref openssl.c, \ref crypt.h.
883 */
884 int handle_connect(int fd)
885 {
886 int ret;
887 unsigned char rand_buf[APC_CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
888 unsigned char challenge_hash[HASH_SIZE];
889 char *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
890 size_t numbytes;
891 struct command_context cc_struct = {.u = NULL}, *cc = &cc_struct;
892 struct iovec iov;
893 struct connection_features cf;
894
895 cc->scc.fd = fd;
896 reset_signals();
897 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
898 ret = mark_fd_blocking(fd);
899 if (ret < 0)
900 goto net_err;
901 /* send Welcome message */
902 ret = write_va_buffer(fd, "This is para_server, version "
903 PACKAGE_VERSION ".\n"
904 "Features: sideband,aes_ctr128\n"
905 );
906 if (ret < 0)
907 goto net_err;
908 /* recv auth request line */
909 ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
910 if (ret < 0)
911 goto net_err;
912 ret = parse_auth_request(buf, ret, &cc->u, &cf);
913 if (ret < 0)
914 goto net_err;
915 if (cc->u) {
916 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
917 ret = apc_pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
918 (unsigned char *)buf);
919 if (ret < 0)
920 goto net_err;
921 numbytes = ret;
922 } else {
923 /*
924 * We don't want to reveal our user names, so we send a
925 * challenge to the client even if the user does not exist, and
926 * fail the authentication later.
927 */
928 numbytes = 256;
929 get_random_bytes_or_die((unsigned char *)buf, numbytes);
930 }
931 PARA_DEBUG_LOG("sending %d byte challenge + session key (%zu bytes)\n",
932 APC_CHALLENGE_SIZE, numbytes);
933 ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
934 buf = NULL;
935 if (ret < 0)
936 goto net_err;
937 ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
938 HANDSHAKE_BUFSIZE, &iov);
939 if (ret < 0)
940 goto net_err;
941 buf = iov.iov_base;
942 numbytes = iov.iov_len;
943 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
944 ret = -E_BAD_USER;
945 if (!cc->u)
946 goto net_err;
947 /*
948 * The correct response is the hash of the first APC_CHALLENGE_SIZE bytes
949 * of the random data.
950 */
951 ret = -E_BAD_AUTH;
952 if (numbytes != HASH_SIZE)
953 goto net_err;
954 hash_function((char *)rand_buf, APC_CHALLENGE_SIZE, challenge_hash);
955 if (memcmp(challenge_hash, buf, HASH_SIZE))
956 goto net_err;
957 /* auth successful */
958 alarm(0);
959 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
960 /* init stream cipher keys with the second part of the random buffer */
961 cc->scc.recv = sc_new(rand_buf + APC_CHALLENGE_SIZE, SESSION_KEY_LEN);
962 cc->scc.send = sc_new(rand_buf + APC_CHALLENGE_SIZE + SESSION_KEY_LEN,
963 SESSION_KEY_LEN);
964 ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
965 if (ret < 0)
966 goto net_err;
967 ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
968 if (ret < 0)
969 goto net_err;
970 ret = run_command(cc, &iov);
971 free(iov.iov_base);
972 if (ret < 0)
973 goto err_out;
974 if (ret >= 0)
975 goto out;
976 err_out:
977 if (send_strerror(cc, -ret) >= 0)
978 send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
979 net_err:
980 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
981 out:
982 free(buf);
983 free(command);
984 mutex_lock(mmd_mutex);
985 mmd->active_connections--;
986 mutex_unlock(mmd_mutex);
987 if (ret >= 0) {
988 ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
989 if (ret < 0)
990 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
991 }
992 sc_free(cc->scc.recv);
993 sc_free(cc->scc.send);
994 return ret;
995 }