Replace status item DBINFO2 by ATTRIBUTES.
[paraslash.git] / command.c
1 /*
2 * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file command.c Client authentication and server commands. */
8
9 #include <signal.h>
10 #include <sys/time.h>
11 #include <sys/types.h>
12 #include <dirent.h>
13 #include <openssl/rc4.h>
14
15 #include "para.h"
16 #include "error.h"
17 #include "server.cmdline.h"
18 #include "string.h"
19 #include "afh.h"
20 #include "afs.h"
21 #include "server.h"
22 #include "vss.h"
23 #include "send.h"
24 #include "rc4.h"
25 #include "net.h"
26 #include "daemon.h"
27 #include "fd.h"
28 #include "list.h"
29 #include "user_list.h"
30 #include "server_command_list.h"
31 #include "afs_command_list.h"
32
33 /** Commands including options must be shorter than this. */
34 #define MAX_COMMAND_LEN 32768
35
36 static RC4_KEY rc4_recv_key;
37 static RC4_KEY rc4_send_key;
38 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
39
40 extern const char *status_item_list[NUM_STAT_ITEMS];
41 extern struct misc_meta_data *mmd;
42 extern struct sender senders[];
43
44 static void dummy(__a_unused int s)
45 {}
46
47 static void mmd_dup(struct misc_meta_data *new_mmd)
48 {
49 mmd_lock();
50 *new_mmd = *mmd;
51 mmd_unlock();
52 }
53
54 /*
55 * compute human readable string containing
56 * vss status for given integer value
57 */
58 static char *vss_status_tohuman(unsigned int flags)
59 {
60 if (flags & VSS_PLAYING)
61 return para_strdup("playing");
62 else if (flags & VSS_NEXT)
63 return para_strdup("stopped");
64 else
65 return para_strdup("paused");
66 }
67
68 /*
69 * return human readable permission string. Never returns NULL.
70 */
71 static char *cmd_perms_itohuman(unsigned int perms)
72 {
73 char *msg = para_malloc(5 * sizeof(char));
74
75 msg[0] = perms & AFS_READ? 'a' : '-';
76 msg[1] = perms & AFS_WRITE? 'A' : '-';
77 msg[2] = perms & VSS_READ? 'v' : '-';
78 msg[3] = perms & VSS_WRITE? 'V' : '-';
79 msg[4] = '\0';
80 return msg;
81 }
82
83 /*
84 * Never returns NULL.
85 */
86 static char *vss_get_status_flags(unsigned int flags)
87 {
88 char *msg = para_malloc(5 * sizeof(char));
89
90 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
91 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
92 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
93 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
94 msg[4] = '\0';
95 return msg;
96 }
97
98 static char *get_status(struct misc_meta_data *nmmd)
99 {
100 char *bar, *ret, mtime[30] = "";
101 char *status, *flags; /* vss status info */
102 char *ut = uptime_str();
103 long offset = (nmmd->offset + 500) / 1000;
104 struct timeval now;
105 struct tm mtime_tm;
106
107 localtime_r(&nmmd->mtime, &mtime_tm);
108 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
109 /* report real status */
110 status = vss_status_tohuman(nmmd->vss_status_flags);
111 flags = vss_get_status_flags(nmmd->vss_status_flags);
112 bar = para_basename(nmmd->filename);
113 gettimeofday(&now, NULL);
114 ret = make_message(
115 "%s:%zu\n" "%s:%s\n" "%s:%lu\n" "%s:%u\n"
116 "%s:%s\n" "%s:%s\n" "%s:%s\n" "%s:%s\n"
117 "%s:%li\n" "%s:%s\n" "%s:%s\n" "%s"
118 "%s:%s\n" "%s:%lu.%lu\n" "%s:%lu.%lu\n" "%s:%s\n",
119 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
120 status_item_list[SI_MTIME], mtime,
121 status_item_list[SI_LENGTH], nmmd->afd.afhi.seconds_total,
122 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
123
124 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
125 status_item_list[SI_STATUS], status,
126 status_item_list[SI_STATUS_FLAGS], flags,
127 status_item_list[SI_SELECTOR], "FIXME",
128
129 status_item_list[SI_OFFSET], offset,
130 status_item_list[SI_FORMAT], audio_format_name(nmmd->afd.afsi.audio_format_id),
131 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
132 nmmd->afd.afhi.info_string,
133
134 status_item_list[SI_UPTIME], ut,
135 status_item_list[SI_STREAM_START],
136 (long unsigned)nmmd->stream_start.tv_sec,
137 (long unsigned)nmmd->stream_start.tv_usec,
138 status_item_list[SI_CURRENT_TIME],
139 (long unsigned)now.tv_sec,
140 (long unsigned)now.tv_usec,
141 status_item_list[SI_ATTRIBUTES], mmd->afd.attributes_string
142
143 );
144 free(bar);
145 free(flags);
146 free(status);
147 free(ut);
148 return ret;
149 }
150
151 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
152 {
153 int i;
154 /* this has to match sender.h */
155 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
156
157 scd->sender_num = -1;
158 if (argc < 2)
159 return -E_COMMAND_SYNTAX;
160 for (i = 0; senders[i].name; i++)
161 if (!strcmp(senders[i].name, argv[1]))
162 break;
163 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
164 if (!senders[i].name)
165 return -E_COMMAND_SYNTAX;
166 scd->sender_num = i;
167 for (i = 0; subcmds[i]; i++)
168 if (!strcmp(subcmds[i], argv[2]))
169 break;
170 if (!subcmds[i])
171 return -E_COMMAND_SYNTAX;
172 scd->cmd_num = i;
173 mmd_lock();
174 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
175 mmd_unlock();
176 return -E_SENDER_CMD;
177 }
178 mmd_unlock();
179 switch (scd->cmd_num) {
180 case SENDER_ON:
181 case SENDER_OFF:
182 if (argc != 3)
183 return -E_COMMAND_SYNTAX;
184 break;
185 case SENDER_DENY:
186 case SENDER_ALLOW:
187 if (argc != 4 && argc != 5)
188 return -E_COMMAND_SYNTAX;
189 if (!inet_pton(AF_INET, argv[3], &scd->addr))
190 return -E_COMMAND_SYNTAX;
191 scd->netmask = 32;
192 if (argc == 5) {
193 scd->netmask = atoi(argv[4]);
194 if (scd->netmask < 0 || scd->netmask > 32)
195 return -E_COMMAND_SYNTAX;
196 }
197 break;
198 case SENDER_ADD:
199 case SENDER_DELETE:
200 if (argc != 4 && argc != 5)
201 return -E_COMMAND_SYNTAX;
202 if (!inet_pton(AF_INET, argv[3], &scd->addr))
203 return -E_COMMAND_SYNTAX;
204 scd->port = -1;
205 if (argc == 5) {
206 scd->port = atoi(argv[4]);
207 if (scd->port < 0 || scd->port > 65535)
208 return -E_COMMAND_SYNTAX;
209 }
210 break;
211 default:
212 return -E_COMMAND_SYNTAX;
213 }
214 return 1;
215 }
216
217 int com_sender(int fd, int argc, char * const * argv)
218 {
219 int i, ret;
220 struct sender_command_data scd;
221
222 if (argc < 2) {
223 char *msg = NULL;
224 for (i = 0; senders[i].name; i++) {
225 char *tmp = make_message("%s%s\n",
226 msg? msg : "", senders[i].name);
227 free(msg);
228 msg = tmp;
229 }
230 ret = send_buffer(fd, msg);
231 free(msg);
232 return ret;
233 }
234 ret = check_sender_args(argc, argv, &scd);
235 if (ret < 0) {
236 char *msg;
237 if (scd.sender_num < 0)
238 return ret;
239 msg = senders[scd.sender_num].help();
240 send_buffer(fd, msg);
241 free(msg);
242 return 1;
243 }
244 for (i = 0; i < 10; i++) {
245 mmd_lock();
246 if (mmd->sender_cmd_data.cmd_num >= 0) {
247 mmd_unlock();
248 usleep(100 * 1000);
249 continue;
250 }
251 mmd->sender_cmd_data = scd;
252 mmd_unlock();
253 break;
254 }
255 return (i < 10)? 1 : -E_LOCK;
256 }
257
258 /* server info */
259 int com_si(int fd, int argc, __a_unused char * const * argv)
260 {
261 int i, ret;
262 char *ut;
263 char *sender_info = NULL, *sender_list = NULL;
264
265 if (argc != 1)
266 return -E_COMMAND_SYNTAX;
267 mmd_lock();
268 for (i = 0; senders[i].name; i++) {
269 char *info = senders[i].info();
270 sender_info = para_strcat(sender_info, info);
271 free(info);
272 sender_list = para_strcat(sender_list, senders[i].name);
273 sender_list = para_strcat(sender_list, " ");
274 }
275 ut = uptime_str();
276 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
277 "pid: %d\n"
278 "connections (active/accepted/total): %u/%u/%u\n"
279 "current loglevel: %i\n"
280 "supported audio formats: %s\n"
281 "supported senders: %s\n"
282 "%s",
283 ut, mmd->num_played,
284 getppid(),
285 mmd->active_connections,
286 mmd->num_commands,
287 mmd->num_connects,
288 conf.loglevel_arg,
289 supported_audio_formats(),
290 sender_list,
291 sender_info
292 );
293 mmd_unlock();
294 free(ut);
295 free(sender_list);
296 free(sender_info);
297 return ret;
298 }
299
300 /* version */
301 int com_version(int fd, int argc, __a_unused char * const * argv)
302 {
303 if (argc != 1)
304 return -E_COMMAND_SYNTAX;
305 return send_buffer(fd, VERSION_TEXT("server")
306 "built: " BUILD_DATE "\n"
307 SYSTEM ", " CC_VERSION "\n"
308 );
309 }
310
311 /* stat */
312 int com_stat(int fd, int argc, char * const * argv)
313 {
314 int ret, num = 0;/* status will be printed that many
315 * times. num <= 0 means: print forever
316 */
317 struct misc_meta_data tmp, *nmmd = &tmp;
318 char *s;
319
320 signal(SIGUSR1, dummy);
321
322 if (argc > 1)
323 num = atoi(argv[1]);
324 for (;;) {
325
326 mmd_dup(nmmd);
327 s = get_status(nmmd);
328 ret = send_buffer(fd, s);
329 free(s);
330 if (ret < 0)
331 goto out;
332 ret = 1;
333 if (num == 1)
334 goto out;
335 sleep(50);
336 if (getppid() == 1)
337 return -E_SERVER_CRASH;
338 }
339 out:
340 return ret;
341 }
342
343 static int send_list_of_commands(int fd, struct server_command *cmd,
344 const char *handler)
345 {
346 int ret, i;
347
348 for (i = 1; cmd->name; cmd++, i++) {
349 char *perms = cmd_perms_itohuman(cmd->perms);
350 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
351 handler,
352 perms,
353 cmd->description);
354 free(perms);
355 if (ret < 0)
356 return ret;
357 }
358 return 1;
359 }
360
361 /* returns string that must be freed by the caller */
362 static struct server_command *get_cmd_ptr(const char *name, char **handler)
363 {
364 struct server_command *cmd;
365
366 for (cmd = server_cmds; cmd->name; cmd++)
367 if (!strcmp(cmd->name, name)) {
368 if (handler)
369 *handler = para_strdup("para_server"); /* server commands */
370 return cmd;
371 }
372 /* not found, look for commands supported by afs */
373 for (cmd = afs_cmds; cmd->name; cmd++)
374 if (!strcmp(cmd->name, name))
375 return cmd;
376 return NULL;
377 }
378
379 /* help */
380 int com_help(int fd, int argc, char * const * argv)
381 {
382 struct server_command *cmd;
383 char *perms, *handler;
384 int ret;
385
386 if (argc < 2) {
387 /* no argument given, print list of commands */
388 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
389 return ret;
390 return send_list_of_commands(fd, afs_cmds, "afs");
391 }
392 /* argument given for help */
393 cmd = get_cmd_ptr(argv[1], &handler);
394 if (!cmd) {
395 free(handler);
396 return -E_BAD_CMD;
397 }
398 perms = cmd_perms_itohuman(cmd->perms);
399 ret = send_va_buffer(fd,
400 "%s - %s\n\n"
401 "handler: %s\n"
402 "permissions: %s\n"
403 "usage: %s\n\n"
404 "%s\n",
405 argv[1],
406 cmd->description,
407 handler,
408 perms,
409 cmd->usage,
410 cmd->help
411 );
412 free(perms);
413 free(handler);
414 return ret;
415 }
416
417 /* hup */
418 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
419 {
420 if (argc != 1)
421 return -E_COMMAND_SYNTAX;
422 kill(getppid(), SIGHUP);
423 return 1;
424 }
425
426 /* term */
427 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
428 {
429 if (argc != 1)
430 return -E_COMMAND_SYNTAX;
431 kill(getppid(), SIGTERM);
432 return 1;
433 }
434
435 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
436 {
437 if (argc != 1)
438 return -E_COMMAND_SYNTAX;
439 mmd_lock();
440 mmd->new_vss_status_flags |= VSS_PLAYING;
441 mmd->new_vss_status_flags &= ~VSS_NOMORE;
442 mmd_unlock();
443 return 1;
444
445 }
446
447 /* stop */
448 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
449 {
450 if (argc != 1)
451 return -E_COMMAND_SYNTAX;
452 mmd_lock();
453 mmd->new_vss_status_flags &= ~VSS_PLAYING;
454 mmd->new_vss_status_flags &= ~VSS_REPOS;
455 mmd->new_vss_status_flags |= VSS_NEXT;
456 mmd_unlock();
457 return 1;
458 }
459
460 /* pause */
461 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
462 {
463 if (argc != 1)
464 return -E_COMMAND_SYNTAX;
465 mmd_lock();
466 if (!vss_paused())
467 mmd->events++;
468 mmd->new_vss_status_flags &= ~VSS_PLAYING;
469 mmd->new_vss_status_flags &= ~VSS_NEXT;
470 mmd_unlock();
471 return 1;
472 }
473
474 /* next */
475 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
476 {
477 if (argc != 1)
478 return -E_COMMAND_SYNTAX;
479 mmd_lock();
480 mmd->events++;
481 mmd->new_vss_status_flags |= VSS_NEXT;
482 mmd_unlock();
483 return 1;
484 }
485
486 /* nomore */
487 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
488 {
489 if (argc != 1)
490 return -E_COMMAND_SYNTAX;
491 mmd_lock();
492 if (vss_playing() || vss_paused())
493 mmd->new_vss_status_flags |= VSS_NOMORE;
494 mmd_unlock();
495 return 1;
496 }
497
498 /* ff */
499 int com_ff(__a_unused int fd, int argc, char * const * argv)
500 {
501 long promille;
502 int ret, backwards = 0;
503 unsigned i;
504 char c;
505
506 if (argc != 2)
507 return -E_COMMAND_SYNTAX;
508 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
509 return -E_COMMAND_SYNTAX;
510 if (ret > 1 && c == '-')
511 backwards = 1; /* jmp backwards */
512 mmd_lock();
513 ret = -E_NO_AUDIO_FILE;
514 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
515 goto out;
516 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
517 if (backwards)
518 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
519 else
520 promille += 1000 * i / mmd->afd.afhi.seconds_total;
521 if (promille < 0)
522 promille = 0;
523 if (promille > 1000) {
524 mmd->new_vss_status_flags |= VSS_NEXT;
525 goto out;
526 }
527 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
528 mmd->new_vss_status_flags |= VSS_REPOS;
529 mmd->new_vss_status_flags &= ~VSS_NEXT;
530 mmd->events++;
531 ret = 1;
532 out:
533 mmd_unlock();
534 return ret;
535 }
536
537 /* jmp */
538 int com_jmp(__a_unused int fd, int argc, char * const * argv)
539 {
540 long unsigned int i;
541 int ret;
542
543 if (argc != 2)
544 return -E_COMMAND_SYNTAX;
545 if (sscanf(argv[1], "%lu", &i) <= 0)
546 return -E_COMMAND_SYNTAX;
547 mmd_lock();
548 ret = -E_NO_AUDIO_FILE;
549 if (!mmd->afd.afhi.chunks_total)
550 goto out;
551 if (i > 100)
552 i = 100;
553 PARA_INFO_LOG("jumping to %lu%%\n", i);
554 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
555 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
556 mmd->chunks_sent, mmd->offset);
557 mmd->new_vss_status_flags |= VSS_REPOS;
558 mmd->new_vss_status_flags &= ~VSS_NEXT;
559 ret = 1;
560 mmd->events++;
561 out:
562 mmd_unlock();
563 return ret;
564 }
565
566 /*
567 * check if perms are sufficient to exec a command having perms cmd_perms.
568 * Returns 0 if perms are sufficient, -E_PERM otherwise.
569 */
570 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
571 {
572 PARA_DEBUG_LOG("%s", "checking permissions\n");
573 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
574 }
575
576 /*
577 * Parse first string from *cmd and lookup in table of valid commands.
578 * On error, NULL is returned.
579 */
580 static struct server_command *parse_cmd(const char *cmdstr)
581 {
582 char buf[255];
583 int n = 0;
584
585 sscanf(cmdstr, "%200s%n", buf, &n);
586 if (!n)
587 return NULL;
588 buf[n] = '\0';
589 return get_cmd_ptr(buf, NULL);
590 }
591
592 static long int para_rand(long unsigned max)
593 {
594 return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
595 }
596
597 static void init_rc4_keys(void)
598 {
599 int i;
600
601 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
602 rc4_buf[i] = para_rand(256);
603 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
604 (unsigned char) rc4_buf[0],
605 (unsigned char) rc4_buf[RC4_KEY_LEN]);
606 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
607 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
608 }
609
610 static void rc4_recv(unsigned long len, const unsigned char *indata,
611 unsigned char *outdata, __a_unused void *private_data)
612 {
613 RC4(&rc4_recv_key, len, indata, outdata);
614 }
615
616 static void rc4_send(unsigned long len, const unsigned char *indata,
617 unsigned char *outdata, __a_unused void *private_data)
618 {
619 RC4(&rc4_send_key, len, indata, outdata);
620 }
621
622 static int read_command(int fd, char **result)
623 {
624 int ret;
625 char buf[4096];
626 char *command = NULL;
627
628 for (;;) {
629 size_t numbytes;
630 char *p;
631
632 ret = recv_buffer(fd, buf, sizeof(buf));
633 if (ret < 0)
634 goto out;
635 if (!ret)
636 break;
637 numbytes = ret;
638 ret = -E_COMMAND_SYNTAX;
639 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
640 goto out;
641 command = para_strcat(command, buf);
642 p = strstr(command, EOC_MSG);
643 if (p) {
644 *p = '\0';
645 break;
646 }
647 }
648 ret = command? 1 : -E_COMMAND_SYNTAX;
649 out:
650 if (ret < 0)
651 free(command);
652 else
653 *result = command;
654 return ret;
655
656 }
657
658 /**
659 * perform user authentication and execute a command
660 *
661 * \param fd the file descriptor to send output to
662 * \param addr socket address info of peer
663 *
664 * \return EXIT_SUCCESS or EXIT_FAILURE
665 *
666 * Whenever para_server accepts an incoming tcp connection on
667 * the port it listens on, it forks and the resulting child
668 * calls this function.
669 *
670 * An RSA-based challenge/response is used to authenticate
671 * the peer. It that authentication succeeds, a random RC4
672 * session key is generated and sent back to the peer,
673 * encrypted with its RSA public key. From this point on,
674 * all transfers are crypted with this session key.
675 *
676 * Next it is checked if the peer supplied a valid server command or a command
677 * for the audio file selector. If yes, and if the user has sufficient
678 * permissions to execute that command, the function calls the corresponding
679 * command handler which does argument checking and further processing.
680 *
681 * In order to cope with a DOS attacks, a timeout is set up
682 * which terminates the function if the connection was not
683 * authenticated when the timeout expires.
684 *
685 * \sa alarm(2), rc4(3), crypt.c, crypt.h
686 */
687 int handle_connect(int fd, struct sockaddr_in *addr)
688 {
689 int ret, argc, use_rc4 = 0;
690 char buf[4096];
691 unsigned char crypt_buf[MAXLINE];
692 struct user *u;
693 struct server_command *cmd = NULL;
694 long unsigned challenge_nr, chall_response;
695 char **argv = NULL;
696 char *p, *command = NULL;
697 size_t numbytes;
698
699 signal(SIGCHLD, SIG_IGN);
700 signal(SIGINT, SIG_DFL);
701 signal(SIGTERM, SIG_DFL);
702 signal(SIGHUP, SIG_DFL);
703 signal(SIGUSR1, SIG_IGN);
704
705 challenge_nr = random();
706 /* send Welcome message */
707 ret = send_va_buffer(fd, "This is para_server, version "
708 PACKAGE_VERSION ".\n" );
709 if (ret < 0)
710 goto err_out;
711 /* recv auth request line */
712 ret = recv_buffer(fd, buf, sizeof(buf));
713 if (ret < 0)
714 goto err_out;
715 if (ret <= 6) {
716 ret = -E_AUTH;
717 goto err_out;
718 }
719 numbytes = ret;
720 ret = -E_AUTH;
721 if (strncmp(buf, "auth ", 5))
722 goto err_out;
723
724 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
725 p = buf + 5; /* client version < 0.2.6 */
726 else {
727 p = buf + 9; /* client version >= 0.2.6 */
728 use_rc4 = 1;
729 }
730 PARA_DEBUG_LOG("received %s request for user %s\n",
731 use_rc4? "rc4" : "auth", p);
732 ret = -E_BAD_USER;
733 u = lookup_user(p);
734 if (!u)
735 goto err_out;
736 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
737 if (ret <= 0)
738 goto err_out;
739 numbytes = ret;
740 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
741 /* We can't use send_buffer here since buf may contain null bytes */
742 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
743 if (ret < 0)
744 goto err_out;
745 /* recv decrypted number */
746 ret = recv_buffer(fd, buf, sizeof(buf));
747 if (ret < 0)
748 goto err_out;
749 numbytes = ret;
750 ret = -E_AUTH;
751 if (!numbytes)
752 goto err_out;
753 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
754 || chall_response != challenge_nr)
755 goto err_out;
756 /* auth successful, send 'Proceed' message */
757 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
758 sprintf(buf, "%s", PROCEED_MSG);
759 if (use_rc4) {
760 init_rc4_keys();
761 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
762 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
763 if (ret <= 0)
764 goto err_out;
765 numbytes = ret + strlen(PROCEED_MSG) + 1;
766 } else
767 numbytes = strlen(buf);
768 ret = send_bin_buffer(fd, buf, numbytes);
769 if (ret < 0)
770 goto err_out;
771 if (use_rc4)
772 enable_crypt(fd, rc4_recv, rc4_send, NULL);
773 ret = read_command(fd, &command);
774 if (ret < 0)
775 goto err_out;
776 ret = -E_BAD_CMD;
777 cmd = parse_cmd(command);
778 if (!cmd)
779 goto err_out;
780 /* valid command, check permissions */
781 ret = check_perms(u->perms, cmd);
782 if (ret < 0)
783 goto err_out;
784 /* valid command and sufficient perms */
785 alarm(0);
786 argc = split_args(command, &argv, "\n");
787 mmd_lock();
788 mmd->num_commands++;
789 mmd_unlock();
790 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
791 inet_ntoa(addr->sin_addr));
792 ret = cmd->handler(fd, argc, argv);
793 if (ret >= 0) {
794 ret = EXIT_SUCCESS;
795 goto out;
796 }
797 err_out:
798 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
799 if (ret != -E_SEND && ret != -E_RECV)
800 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
801 ret = EXIT_FAILURE;
802 out:
803 free(command);
804 free(argv);
805 mmd_lock();
806 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
807 mmd->events++;
808 mmd->active_connections--;
809 mmd_unlock();
810 return ret;
811 }