Replace status item SELECTOR by IMAGE_ID.
[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 *basename, *dirname, *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 basename = para_basename(nmmd->filename);
113 dirname = para_dirname(nmmd->filename);
114 gettimeofday(&now, NULL);
115 ret = make_message(
116 "%s:%zu\n" "%s:%s\n" "%s:%lu\n" "%s:%u\n"
117 "%s:%s\n" "%s:%s\n" "%s:%s\n" "%s:%u\n"
118 "%s:%li\n" "%s:%s\n" "%s:%s\n" "%s"
119 "%s:%s\n" "%s:%lu.%lu\n" "%s:%lu.%lu\n" "%s:%s\n"
120 "%s:%s\n",
121 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
122 status_item_list[SI_MTIME], mtime,
123 status_item_list[SI_LENGTH], nmmd->afd.afhi.seconds_total,
124 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
125
126 status_item_list[SI_BASENAME], basename ? basename : "(none)",
127 status_item_list[SI_STATUS], status,
128 status_item_list[SI_STATUS_FLAGS], flags,
129 status_item_list[SI_IMAGE_ID], nmmd->afd.afsi.image_id,
130
131 status_item_list[SI_OFFSET], offset,
132 status_item_list[SI_FORMAT], audio_format_name(nmmd->afd.afsi.audio_format_id),
133 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
134 nmmd->afd.afhi.info_string,
135
136 status_item_list[SI_UPTIME], ut,
137 status_item_list[SI_STREAM_START],
138 (long unsigned)nmmd->stream_start.tv_sec,
139 (long unsigned)nmmd->stream_start.tv_usec,
140 status_item_list[SI_CURRENT_TIME],
141 (long unsigned)now.tv_sec,
142 (long unsigned)now.tv_usec,
143 status_item_list[SI_ATTRIBUTES], mmd->afd.attributes_string,
144
145 status_item_list[SI_DIRECTORY], dirname
146
147 );
148 free(basename);
149 free(dirname);
150 free(flags);
151 free(status);
152 free(ut);
153 return ret;
154 }
155
156 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
157 {
158 int i;
159 /* this has to match sender.h */
160 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
161
162 scd->sender_num = -1;
163 if (argc < 2)
164 return -E_COMMAND_SYNTAX;
165 for (i = 0; senders[i].name; i++)
166 if (!strcmp(senders[i].name, argv[1]))
167 break;
168 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
169 if (!senders[i].name)
170 return -E_COMMAND_SYNTAX;
171 scd->sender_num = i;
172 for (i = 0; subcmds[i]; i++)
173 if (!strcmp(subcmds[i], argv[2]))
174 break;
175 if (!subcmds[i])
176 return -E_COMMAND_SYNTAX;
177 scd->cmd_num = i;
178 mmd_lock();
179 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
180 mmd_unlock();
181 return -E_SENDER_CMD;
182 }
183 mmd_unlock();
184 switch (scd->cmd_num) {
185 case SENDER_ON:
186 case SENDER_OFF:
187 if (argc != 3)
188 return -E_COMMAND_SYNTAX;
189 break;
190 case SENDER_DENY:
191 case SENDER_ALLOW:
192 if (argc != 4 && argc != 5)
193 return -E_COMMAND_SYNTAX;
194 if (!inet_pton(AF_INET, argv[3], &scd->addr))
195 return -E_COMMAND_SYNTAX;
196 scd->netmask = 32;
197 if (argc == 5) {
198 scd->netmask = atoi(argv[4]);
199 if (scd->netmask < 0 || scd->netmask > 32)
200 return -E_COMMAND_SYNTAX;
201 }
202 break;
203 case SENDER_ADD:
204 case SENDER_DELETE:
205 if (argc != 4 && argc != 5)
206 return -E_COMMAND_SYNTAX;
207 if (!inet_pton(AF_INET, argv[3], &scd->addr))
208 return -E_COMMAND_SYNTAX;
209 scd->port = -1;
210 if (argc == 5) {
211 scd->port = atoi(argv[4]);
212 if (scd->port < 0 || scd->port > 65535)
213 return -E_COMMAND_SYNTAX;
214 }
215 break;
216 default:
217 return -E_COMMAND_SYNTAX;
218 }
219 return 1;
220 }
221
222 int com_sender(int fd, int argc, char * const * argv)
223 {
224 int i, ret;
225 struct sender_command_data scd;
226
227 if (argc < 2) {
228 char *msg = NULL;
229 for (i = 0; senders[i].name; i++) {
230 char *tmp = make_message("%s%s\n",
231 msg? msg : "", senders[i].name);
232 free(msg);
233 msg = tmp;
234 }
235 ret = send_buffer(fd, msg);
236 free(msg);
237 return ret;
238 }
239 ret = check_sender_args(argc, argv, &scd);
240 if (ret < 0) {
241 char *msg;
242 if (scd.sender_num < 0)
243 return ret;
244 msg = senders[scd.sender_num].help();
245 send_buffer(fd, msg);
246 free(msg);
247 return 1;
248 }
249 for (i = 0; i < 10; i++) {
250 mmd_lock();
251 if (mmd->sender_cmd_data.cmd_num >= 0) {
252 mmd_unlock();
253 usleep(100 * 1000);
254 continue;
255 }
256 mmd->sender_cmd_data = scd;
257 mmd_unlock();
258 break;
259 }
260 return (i < 10)? 1 : -E_LOCK;
261 }
262
263 /* server info */
264 int com_si(int fd, int argc, __a_unused char * const * argv)
265 {
266 int i, ret;
267 char *ut;
268 char *sender_info = NULL, *sender_list = NULL;
269
270 if (argc != 1)
271 return -E_COMMAND_SYNTAX;
272 mmd_lock();
273 for (i = 0; senders[i].name; i++) {
274 char *info = senders[i].info();
275 sender_info = para_strcat(sender_info, info);
276 free(info);
277 sender_list = para_strcat(sender_list, senders[i].name);
278 sender_list = para_strcat(sender_list, " ");
279 }
280 ut = uptime_str();
281 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
282 "pid: %d\n"
283 "connections (active/accepted/total): %u/%u/%u\n"
284 "current loglevel: %i\n"
285 "supported audio formats: %s\n"
286 "supported senders: %s\n"
287 "%s",
288 ut, mmd->num_played,
289 getppid(),
290 mmd->active_connections,
291 mmd->num_commands,
292 mmd->num_connects,
293 conf.loglevel_arg,
294 supported_audio_formats(),
295 sender_list,
296 sender_info
297 );
298 mmd_unlock();
299 free(ut);
300 free(sender_list);
301 free(sender_info);
302 return ret;
303 }
304
305 /* version */
306 int com_version(int fd, int argc, __a_unused char * const * argv)
307 {
308 if (argc != 1)
309 return -E_COMMAND_SYNTAX;
310 return send_buffer(fd, VERSION_TEXT("server")
311 "built: " BUILD_DATE "\n"
312 SYSTEM ", " CC_VERSION "\n"
313 );
314 }
315
316 /* stat */
317 int com_stat(int fd, int argc, char * const * argv)
318 {
319 int ret, num = 0;/* status will be printed that many
320 * times. num <= 0 means: print forever
321 */
322 struct misc_meta_data tmp, *nmmd = &tmp;
323 char *s;
324
325 signal(SIGUSR1, dummy);
326
327 if (argc > 1)
328 num = atoi(argv[1]);
329 for (;;) {
330
331 mmd_dup(nmmd);
332 s = get_status(nmmd);
333 ret = send_buffer(fd, s);
334 free(s);
335 if (ret < 0)
336 goto out;
337 ret = 1;
338 if (num == 1)
339 goto out;
340 sleep(50);
341 if (getppid() == 1)
342 return -E_SERVER_CRASH;
343 }
344 out:
345 return ret;
346 }
347
348 static int send_list_of_commands(int fd, struct server_command *cmd,
349 const char *handler)
350 {
351 int ret, i;
352
353 for (i = 1; cmd->name; cmd++, i++) {
354 char *perms = cmd_perms_itohuman(cmd->perms);
355 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
356 handler,
357 perms,
358 cmd->description);
359 free(perms);
360 if (ret < 0)
361 return ret;
362 }
363 return 1;
364 }
365
366 /* returns string that must be freed by the caller */
367 static struct server_command *get_cmd_ptr(const char *name, char **handler)
368 {
369 struct server_command *cmd;
370
371 for (cmd = server_cmds; cmd->name; cmd++)
372 if (!strcmp(cmd->name, name)) {
373 if (handler)
374 *handler = para_strdup("para_server"); /* server commands */
375 return cmd;
376 }
377 /* not found, look for commands supported by afs */
378 for (cmd = afs_cmds; cmd->name; cmd++)
379 if (!strcmp(cmd->name, name))
380 return cmd;
381 return NULL;
382 }
383
384 /* help */
385 int com_help(int fd, int argc, char * const * argv)
386 {
387 struct server_command *cmd;
388 char *perms, *handler;
389 int ret;
390
391 if (argc < 2) {
392 /* no argument given, print list of commands */
393 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
394 return ret;
395 return send_list_of_commands(fd, afs_cmds, "afs");
396 }
397 /* argument given for help */
398 cmd = get_cmd_ptr(argv[1], &handler);
399 if (!cmd) {
400 free(handler);
401 return -E_BAD_CMD;
402 }
403 perms = cmd_perms_itohuman(cmd->perms);
404 ret = send_va_buffer(fd,
405 "%s - %s\n\n"
406 "handler: %s\n"
407 "permissions: %s\n"
408 "usage: %s\n\n"
409 "%s\n",
410 argv[1],
411 cmd->description,
412 handler,
413 perms,
414 cmd->usage,
415 cmd->help
416 );
417 free(perms);
418 free(handler);
419 return ret;
420 }
421
422 /* hup */
423 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
424 {
425 if (argc != 1)
426 return -E_COMMAND_SYNTAX;
427 kill(getppid(), SIGHUP);
428 return 1;
429 }
430
431 /* term */
432 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
433 {
434 if (argc != 1)
435 return -E_COMMAND_SYNTAX;
436 kill(getppid(), SIGTERM);
437 return 1;
438 }
439
440 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
441 {
442 if (argc != 1)
443 return -E_COMMAND_SYNTAX;
444 mmd_lock();
445 mmd->new_vss_status_flags |= VSS_PLAYING;
446 mmd->new_vss_status_flags &= ~VSS_NOMORE;
447 mmd_unlock();
448 return 1;
449
450 }
451
452 /* stop */
453 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
454 {
455 if (argc != 1)
456 return -E_COMMAND_SYNTAX;
457 mmd_lock();
458 mmd->new_vss_status_flags &= ~VSS_PLAYING;
459 mmd->new_vss_status_flags &= ~VSS_REPOS;
460 mmd->new_vss_status_flags |= VSS_NEXT;
461 mmd_unlock();
462 return 1;
463 }
464
465 /* pause */
466 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
467 {
468 if (argc != 1)
469 return -E_COMMAND_SYNTAX;
470 mmd_lock();
471 if (!vss_paused())
472 mmd->events++;
473 mmd->new_vss_status_flags &= ~VSS_PLAYING;
474 mmd->new_vss_status_flags &= ~VSS_NEXT;
475 mmd_unlock();
476 return 1;
477 }
478
479 /* next */
480 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
481 {
482 if (argc != 1)
483 return -E_COMMAND_SYNTAX;
484 mmd_lock();
485 mmd->events++;
486 mmd->new_vss_status_flags |= VSS_NEXT;
487 mmd_unlock();
488 return 1;
489 }
490
491 /* nomore */
492 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
493 {
494 if (argc != 1)
495 return -E_COMMAND_SYNTAX;
496 mmd_lock();
497 if (vss_playing() || vss_paused())
498 mmd->new_vss_status_flags |= VSS_NOMORE;
499 mmd_unlock();
500 return 1;
501 }
502
503 /* ff */
504 int com_ff(__a_unused int fd, int argc, char * const * argv)
505 {
506 long promille;
507 int ret, backwards = 0;
508 unsigned i;
509 char c;
510
511 if (argc != 2)
512 return -E_COMMAND_SYNTAX;
513 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
514 return -E_COMMAND_SYNTAX;
515 if (ret > 1 && c == '-')
516 backwards = 1; /* jmp backwards */
517 mmd_lock();
518 ret = -E_NO_AUDIO_FILE;
519 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
520 goto out;
521 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
522 if (backwards)
523 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
524 else
525 promille += 1000 * i / mmd->afd.afhi.seconds_total;
526 if (promille < 0)
527 promille = 0;
528 if (promille > 1000) {
529 mmd->new_vss_status_flags |= VSS_NEXT;
530 goto out;
531 }
532 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
533 mmd->new_vss_status_flags |= VSS_REPOS;
534 mmd->new_vss_status_flags &= ~VSS_NEXT;
535 mmd->events++;
536 ret = 1;
537 out:
538 mmd_unlock();
539 return ret;
540 }
541
542 /* jmp */
543 int com_jmp(__a_unused int fd, int argc, char * const * argv)
544 {
545 long unsigned int i;
546 int ret;
547
548 if (argc != 2)
549 return -E_COMMAND_SYNTAX;
550 if (sscanf(argv[1], "%lu", &i) <= 0)
551 return -E_COMMAND_SYNTAX;
552 mmd_lock();
553 ret = -E_NO_AUDIO_FILE;
554 if (!mmd->afd.afhi.chunks_total)
555 goto out;
556 if (i > 100)
557 i = 100;
558 PARA_INFO_LOG("jumping to %lu%%\n", i);
559 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
560 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
561 mmd->chunks_sent, mmd->offset);
562 mmd->new_vss_status_flags |= VSS_REPOS;
563 mmd->new_vss_status_flags &= ~VSS_NEXT;
564 ret = 1;
565 mmd->events++;
566 out:
567 mmd_unlock();
568 return ret;
569 }
570
571 /*
572 * check if perms are sufficient to exec a command having perms cmd_perms.
573 * Returns 0 if perms are sufficient, -E_PERM otherwise.
574 */
575 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
576 {
577 PARA_DEBUG_LOG("%s", "checking permissions\n");
578 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
579 }
580
581 /*
582 * Parse first string from *cmd and lookup in table of valid commands.
583 * On error, NULL is returned.
584 */
585 static struct server_command *parse_cmd(const char *cmdstr)
586 {
587 char buf[255];
588 int n = 0;
589
590 sscanf(cmdstr, "%200s%n", buf, &n);
591 if (!n)
592 return NULL;
593 buf[n] = '\0';
594 return get_cmd_ptr(buf, NULL);
595 }
596
597 static long int para_rand(long unsigned max)
598 {
599 return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
600 }
601
602 static void init_rc4_keys(void)
603 {
604 int i;
605
606 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
607 rc4_buf[i] = para_rand(256);
608 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
609 (unsigned char) rc4_buf[0],
610 (unsigned char) rc4_buf[RC4_KEY_LEN]);
611 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
612 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
613 }
614
615 static void rc4_recv(unsigned long len, const unsigned char *indata,
616 unsigned char *outdata, __a_unused void *private_data)
617 {
618 RC4(&rc4_recv_key, len, indata, outdata);
619 }
620
621 static void rc4_send(unsigned long len, const unsigned char *indata,
622 unsigned char *outdata, __a_unused void *private_data)
623 {
624 RC4(&rc4_send_key, len, indata, outdata);
625 }
626
627 static int read_command(int fd, char **result)
628 {
629 int ret;
630 char buf[4096];
631 char *command = NULL;
632
633 for (;;) {
634 size_t numbytes;
635 char *p;
636
637 ret = recv_buffer(fd, buf, sizeof(buf));
638 if (ret < 0)
639 goto out;
640 if (!ret)
641 break;
642 numbytes = ret;
643 ret = -E_COMMAND_SYNTAX;
644 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
645 goto out;
646 command = para_strcat(command, buf);
647 p = strstr(command, EOC_MSG);
648 if (p) {
649 *p = '\0';
650 break;
651 }
652 }
653 ret = command? 1 : -E_COMMAND_SYNTAX;
654 out:
655 if (ret < 0)
656 free(command);
657 else
658 *result = command;
659 return ret;
660
661 }
662
663 /**
664 * perform user authentication and execute a command
665 *
666 * \param fd the file descriptor to send output to
667 * \param addr socket address info of peer
668 *
669 * \return EXIT_SUCCESS or EXIT_FAILURE
670 *
671 * Whenever para_server accepts an incoming tcp connection on
672 * the port it listens on, it forks and the resulting child
673 * calls this function.
674 *
675 * An RSA-based challenge/response is used to authenticate
676 * the peer. It that authentication succeeds, a random RC4
677 * session key is generated and sent back to the peer,
678 * encrypted with its RSA public key. From this point on,
679 * all transfers are crypted with this session key.
680 *
681 * Next it is checked if the peer supplied a valid server command or a command
682 * for the audio file selector. If yes, and if the user has sufficient
683 * permissions to execute that command, the function calls the corresponding
684 * command handler which does argument checking and further processing.
685 *
686 * In order to cope with a DOS attacks, a timeout is set up
687 * which terminates the function if the connection was not
688 * authenticated when the timeout expires.
689 *
690 * \sa alarm(2), rc4(3), crypt.c, crypt.h
691 */
692 int handle_connect(int fd, struct sockaddr_in *addr)
693 {
694 int ret, argc, use_rc4 = 0;
695 char buf[4096];
696 unsigned char crypt_buf[MAXLINE];
697 struct user *u;
698 struct server_command *cmd = NULL;
699 long unsigned challenge_nr, chall_response;
700 char **argv = NULL;
701 char *p, *command = NULL;
702 size_t numbytes;
703
704 signal(SIGCHLD, SIG_IGN);
705 signal(SIGINT, SIG_DFL);
706 signal(SIGTERM, SIG_DFL);
707 signal(SIGHUP, SIG_DFL);
708 signal(SIGUSR1, SIG_IGN);
709
710 challenge_nr = random();
711 /* send Welcome message */
712 ret = send_va_buffer(fd, "This is para_server, version "
713 PACKAGE_VERSION ".\n" );
714 if (ret < 0)
715 goto err_out;
716 /* recv auth request line */
717 ret = recv_buffer(fd, buf, sizeof(buf));
718 if (ret < 0)
719 goto err_out;
720 if (ret <= 6) {
721 ret = -E_AUTH;
722 goto err_out;
723 }
724 numbytes = ret;
725 ret = -E_AUTH;
726 if (strncmp(buf, "auth ", 5))
727 goto err_out;
728
729 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
730 p = buf + 5; /* client version < 0.2.6 */
731 else {
732 p = buf + 9; /* client version >= 0.2.6 */
733 use_rc4 = 1;
734 }
735 PARA_DEBUG_LOG("received %s request for user %s\n",
736 use_rc4? "rc4" : "auth", p);
737 ret = -E_BAD_USER;
738 u = lookup_user(p);
739 if (!u)
740 goto err_out;
741 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
742 if (ret <= 0)
743 goto err_out;
744 numbytes = ret;
745 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
746 /* We can't use send_buffer here since buf may contain null bytes */
747 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
748 if (ret < 0)
749 goto err_out;
750 /* recv decrypted number */
751 ret = recv_buffer(fd, buf, sizeof(buf));
752 if (ret < 0)
753 goto err_out;
754 numbytes = ret;
755 ret = -E_AUTH;
756 if (!numbytes)
757 goto err_out;
758 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
759 || chall_response != challenge_nr)
760 goto err_out;
761 /* auth successful, send 'Proceed' message */
762 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
763 sprintf(buf, "%s", PROCEED_MSG);
764 if (use_rc4) {
765 init_rc4_keys();
766 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
767 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
768 if (ret <= 0)
769 goto err_out;
770 numbytes = ret + strlen(PROCEED_MSG) + 1;
771 } else
772 numbytes = strlen(buf);
773 ret = send_bin_buffer(fd, buf, numbytes);
774 if (ret < 0)
775 goto err_out;
776 if (use_rc4)
777 enable_crypt(fd, rc4_recv, rc4_send, NULL);
778 ret = read_command(fd, &command);
779 if (ret < 0)
780 goto err_out;
781 ret = -E_BAD_CMD;
782 cmd = parse_cmd(command);
783 if (!cmd)
784 goto err_out;
785 /* valid command, check permissions */
786 ret = check_perms(u->perms, cmd);
787 if (ret < 0)
788 goto err_out;
789 /* valid command and sufficient perms */
790 alarm(0);
791 argc = split_args(command, &argv, "\n");
792 mmd_lock();
793 mmd->num_commands++;
794 mmd_unlock();
795 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
796 inet_ntoa(addr->sin_addr));
797 ret = cmd->handler(fd, argc, argv);
798 if (ret >= 0) {
799 ret = EXIT_SUCCESS;
800 goto out;
801 }
802 err_out:
803 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
804 if (ret != -E_SEND && ret != -E_RECV)
805 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
806 ret = EXIT_FAILURE;
807 out:
808 free(command);
809 free(argv);
810 mmd_lock();
811 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
812 mmd->events++;
813 mmd->active_connections--;
814 mmd_unlock();
815 return ret;
816 }