vss: Include map in the vss task struct.
[paraslash.git] / command.c
1 /*
2 * Copyright (C) 1997-2008 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 "list.h"
24 #include "send.h"
25 #include "rc4.h"
26 #include "net.h"
27 #include "daemon.h"
28 #include "fd.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 struct misc_meta_data *mmd;
41 extern struct sender senders[];
42
43 static void dummy(int s)
44 {
45 /*
46 * At least on Solaris, SIGUSR1 is one-shot, i.e. the signal action is
47 * restored to the default state once the signal handler has been
48 * called.
49 */
50 if (s == SIGUSR1)
51 signal(SIGUSR1, dummy);
52 }
53
54 static void mmd_dup(struct misc_meta_data *new_mmd)
55 {
56 mmd_lock();
57 *new_mmd = *mmd;
58 mmd_unlock();
59 }
60
61 /*
62 * compute human readable string containing
63 * vss status for given integer value
64 */
65 static char *vss_status_tohuman(unsigned int flags)
66 {
67 if (flags & VSS_PLAYING)
68 return para_strdup("playing");
69 else if (flags & VSS_NEXT)
70 return para_strdup("stopped");
71 else
72 return para_strdup("paused");
73 }
74
75 /*
76 * return human readable permission string. Never returns NULL.
77 */
78 static char *cmd_perms_itohuman(unsigned int perms)
79 {
80 char *msg = para_malloc(5 * sizeof(char));
81
82 msg[0] = perms & AFS_READ? 'a' : '-';
83 msg[1] = perms & AFS_WRITE? 'A' : '-';
84 msg[2] = perms & VSS_READ? 'v' : '-';
85 msg[3] = perms & VSS_WRITE? 'V' : '-';
86 msg[4] = '\0';
87 return msg;
88 }
89
90 /*
91 * Never returns NULL.
92 */
93 static char *vss_get_status_flags(unsigned int flags)
94 {
95 char *msg = para_malloc(5 * sizeof(char));
96
97 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
98 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
99 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
100 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
101 msg[4] = '\0';
102 return msg;
103 }
104
105 static char *get_status(struct misc_meta_data *nmmd)
106 {
107 char *ret, mtime[30] = "";
108 char *status, *flags; /* vss status info */
109 char *ut = uptime_str();
110 long offset = (nmmd->offset + 500) / 1000;
111 struct timeval now;
112 struct tm mtime_tm;
113
114 /* report real status */
115 status = vss_status_tohuman(nmmd->vss_status_flags);
116 flags = vss_get_status_flags(nmmd->vss_status_flags);
117 if (nmmd->size) { /* parent currently has an audio file open */
118 localtime_r(&nmmd->mtime, &mtime_tm);
119 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
120 }
121 gettimeofday(&now, NULL);
122 ret = make_message(
123 "%s: %zu\n" /* file size */
124 "%s: %s\n" /* mtime */
125 "%s: %s\n" /* status */
126 "%s: %s\n" /* status flags */
127 "%s: %li\n" /* offset */
128 "%s: %s\n" /* afs mode */
129 "%s: %lu.%lu\n" /* stream start */
130 "%s: %lu.%lu\n" /* current server time */
131 "%s", /* afs status info */
132 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
133 status_item_list[SI_MTIME], mtime,
134 status_item_list[SI_STATUS], status,
135 status_item_list[SI_STATUS_FLAGS], flags,
136
137 status_item_list[SI_OFFSET], offset,
138 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
139
140 status_item_list[SI_STREAM_START],
141 (long unsigned)nmmd->stream_start.tv_sec,
142 (long unsigned)nmmd->stream_start.tv_usec,
143 status_item_list[SI_CURRENT_TIME],
144 (long unsigned)now.tv_sec,
145 (long unsigned)now.tv_usec,
146
147 nmmd->afd.verbose_ls_output
148
149 );
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 ret = send_buffer(fd, msg);
246 free(msg);
247 return ret;
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 (int)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 UNAME_RS ", " 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 > 0 && !--num)
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("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 if (handler)
381 *handler = para_strdup("afs");
382 return cmd;
383 }
384 return NULL;
385 }
386
387 /* help */
388 int com_help(int fd, int argc, char * const * argv)
389 {
390 struct server_command *cmd;
391 char *perms, *handler;
392 int ret;
393
394 if (argc < 2) {
395 /* no argument given, print list of commands */
396 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
397 return ret;
398 return send_list_of_commands(fd, afs_cmds, "afs");
399 }
400 /* argument given for help */
401 cmd = get_cmd_ptr(argv[1], &handler);
402 if (!cmd) {
403 free(handler);
404 return -E_BAD_CMD;
405 }
406 perms = cmd_perms_itohuman(cmd->perms);
407 ret = send_va_buffer(fd,
408 "%s - %s\n\n"
409 "handler: %s\n"
410 "permissions: %s\n"
411 "usage: %s\n\n"
412 "%s\n",
413 argv[1],
414 cmd->description,
415 handler,
416 perms,
417 cmd->usage,
418 cmd->help
419 );
420 free(perms);
421 free(handler);
422 return ret;
423 }
424
425 /* hup */
426 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
427 {
428 if (argc != 1)
429 return -E_COMMAND_SYNTAX;
430 kill(getppid(), SIGHUP);
431 return 1;
432 }
433
434 /* term */
435 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
436 {
437 if (argc != 1)
438 return -E_COMMAND_SYNTAX;
439 kill(getppid(), SIGTERM);
440 return 1;
441 }
442
443 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
444 {
445 if (argc != 1)
446 return -E_COMMAND_SYNTAX;
447 mmd_lock();
448 mmd->new_vss_status_flags |= VSS_PLAYING;
449 mmd->new_vss_status_flags &= ~VSS_NOMORE;
450 mmd_unlock();
451 return 1;
452
453 }
454
455 /* stop */
456 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
457 {
458 if (argc != 1)
459 return -E_COMMAND_SYNTAX;
460 mmd_lock();
461 mmd->new_vss_status_flags &= ~VSS_PLAYING;
462 mmd->new_vss_status_flags &= ~VSS_REPOS;
463 mmd->new_vss_status_flags |= VSS_NEXT;
464 mmd_unlock();
465 return 1;
466 }
467
468 /* pause */
469 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
470 {
471 if (argc != 1)
472 return -E_COMMAND_SYNTAX;
473 mmd_lock();
474 if (!vss_paused() && !vss_stopped()) {
475 mmd->events++;
476 mmd->new_vss_status_flags &= ~VSS_PLAYING;
477 mmd->new_vss_status_flags &= ~VSS_NEXT;
478 }
479 mmd_unlock();
480 return 1;
481 }
482
483 /* next */
484 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
485 {
486 if (argc != 1)
487 return -E_COMMAND_SYNTAX;
488 mmd_lock();
489 mmd->events++;
490 mmd->new_vss_status_flags |= VSS_NEXT;
491 mmd_unlock();
492 return 1;
493 }
494
495 /* nomore */
496 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
497 {
498 if (argc != 1)
499 return -E_COMMAND_SYNTAX;
500 mmd_lock();
501 if (vss_playing() || vss_paused())
502 mmd->new_vss_status_flags |= VSS_NOMORE;
503 mmd_unlock();
504 return 1;
505 }
506
507 /* ff */
508 int com_ff(__a_unused int fd, int argc, char * const * argv)
509 {
510 long promille;
511 int ret, backwards = 0;
512 unsigned i;
513 char c;
514
515 if (argc != 2)
516 return -E_COMMAND_SYNTAX;
517 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
518 return -E_COMMAND_SYNTAX;
519 if (ret > 1 && c == '-')
520 backwards = 1; /* jmp backwards */
521 mmd_lock();
522 ret = -E_NO_AUDIO_FILE;
523 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
524 goto out;
525 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
526 if (backwards)
527 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
528 else
529 promille += 1000 * i / mmd->afd.afhi.seconds_total;
530 if (promille < 0)
531 promille = 0;
532 if (promille > 1000) {
533 mmd->new_vss_status_flags |= VSS_NEXT;
534 goto out;
535 }
536 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
537 mmd->new_vss_status_flags |= VSS_REPOS;
538 mmd->new_vss_status_flags &= ~VSS_NEXT;
539 mmd->events++;
540 ret = 1;
541 out:
542 mmd_unlock();
543 return ret;
544 }
545
546 /* jmp */
547 int com_jmp(__a_unused int fd, int argc, char * const * argv)
548 {
549 long unsigned int i;
550 int ret;
551
552 if (argc != 2)
553 return -E_COMMAND_SYNTAX;
554 if (sscanf(argv[1], "%lu", &i) <= 0)
555 return -E_COMMAND_SYNTAX;
556 mmd_lock();
557 ret = -E_NO_AUDIO_FILE;
558 if (!mmd->afd.afhi.chunks_total)
559 goto out;
560 if (i > 100)
561 i = 100;
562 PARA_INFO_LOG("jumping to %lu%%\n", i);
563 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
564 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
565 mmd->chunks_sent, mmd->offset);
566 mmd->new_vss_status_flags |= VSS_REPOS;
567 mmd->new_vss_status_flags &= ~VSS_NEXT;
568 ret = 1;
569 mmd->events++;
570 out:
571 mmd_unlock();
572 return ret;
573 }
574
575 /*
576 * check if perms are sufficient to exec a command having perms cmd_perms.
577 * Returns 0 if perms are sufficient, -E_PERM otherwise.
578 */
579 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
580 {
581 PARA_DEBUG_LOG("checking permissions\n");
582 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
583 }
584
585 /*
586 * Parse first string from *cmd and lookup in table of valid commands.
587 * On error, NULL is returned.
588 */
589 static struct server_command *parse_cmd(const char *cmdstr)
590 {
591 char buf[255];
592 int n = 0;
593
594 sscanf(cmdstr, "%200s%n", buf, &n);
595 if (!n)
596 return NULL;
597 buf[n] = '\0';
598 return get_cmd_ptr(buf, NULL);
599 }
600
601 static void init_rc4_keys(void)
602 {
603 int i;
604
605 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
606 rc4_buf[i] = para_random(256);
607 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
608 (unsigned char) rc4_buf[0],
609 (unsigned char) rc4_buf[RC4_KEY_LEN]);
610 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
611 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
612 }
613
614 static void rc4_recv(unsigned long len, const unsigned char *indata,
615 unsigned char *outdata, __a_unused void *private_data)
616 {
617 RC4(&rc4_recv_key, len, indata, outdata);
618 }
619
620 static void rc4_send(unsigned long len, const unsigned char *indata,
621 unsigned char *outdata, __a_unused void *private_data)
622 {
623 RC4(&rc4_send_key, len, indata, outdata);
624 }
625
626 static int read_command(int fd, char **result)
627 {
628 int ret;
629 char buf[4096];
630 char *command = NULL;
631
632 for (;;) {
633 size_t numbytes;
634 char *p;
635
636 ret = recv_buffer(fd, buf, sizeof(buf));
637 if (ret < 0)
638 goto out;
639 if (!ret)
640 break;
641 numbytes = ret;
642 ret = -E_COMMAND_SYNTAX;
643 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
644 goto out;
645 command = para_strcat(command, buf);
646 p = strstr(command, EOC_MSG);
647 if (p) {
648 *p = '\0';
649 break;
650 }
651 }
652 ret = command? 1 : -E_COMMAND_SYNTAX;
653 out:
654 if (ret < 0)
655 free(command);
656 else
657 *result = command;
658 return ret;
659
660 }
661
662 /**
663 * Perform user authentication and execute a command.
664 *
665 * \param fd The file descriptor to send output to.
666 * \param peername Identifies the connecting peer.
667 *
668 * Whenever para_server accepts an incoming tcp connection on
669 * the port it listens on, it forks and the resulting child
670 * calls this function.
671 *
672 * An RSA-based challenge/response is used to authenticate
673 * the peer. It that authentication succeeds, a random RC4
674 * session key is generated and sent back to the peer,
675 * encrypted with its RSA public key. From this point on,
676 * all transfers are crypted with this session key.
677 *
678 * Next it is checked if the peer supplied a valid server command or a command
679 * for the audio file selector. If yes, and if the user has sufficient
680 * permissions to execute that command, the function calls the corresponding
681 * command handler which does argument checking and further processing.
682 *
683 * In order to cope with a DOS attacks, a timeout is set up
684 * which terminates the function if the connection was not
685 * authenticated when the timeout expires.
686 *
687 * \sa alarm(2), rc4(3), crypt.c, crypt.h
688 */
689 __noreturn void handle_connect(int fd, const char *peername)
690 {
691 int ret, argc, use_rc4 = 0;
692 char buf[4096];
693 unsigned char crypt_buf[MAXLINE];
694 struct user *u;
695 struct server_command *cmd = NULL;
696 long unsigned challenge_nr, chall_response;
697 char **argv = NULL;
698 char *p, *command = NULL;
699 size_t numbytes;
700
701 signal(SIGCHLD, SIG_IGN);
702 signal(SIGINT, SIG_DFL);
703 signal(SIGTERM, SIG_DFL);
704 signal(SIGHUP, SIG_DFL);
705
706 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
707 ret = mark_fd_blocking(fd);
708 if (ret < 0)
709 goto err_out;
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 net_err;
750 /* recv decrypted number */
751 ret = recv_buffer(fd, buf, sizeof(buf));
752 if (ret < 0)
753 goto net_err;
754 numbytes = ret;
755 ret = -E_AUTH;
756 if (!numbytes)
757 goto net_err;
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 net_err;
776 if (use_rc4)
777 enable_crypt(fd, rc4_recv, rc4_send, NULL);
778 ret = read_command(fd, &command);
779 if (ret == -E_COMMAND_SYNTAX)
780 goto err_out;
781 if (ret < 0)
782 goto net_err;
783 ret = -E_BAD_CMD;
784 cmd = parse_cmd(command);
785 if (!cmd)
786 goto err_out;
787 /* valid command, check permissions */
788 ret = check_perms(u->perms, cmd);
789 if (ret < 0)
790 goto err_out;
791 /* valid command and sufficient perms */
792 alarm(0);
793 argc = split_args(command, &argv, "\n");
794 mmd_lock();
795 mmd->num_commands++;
796 mmd_unlock();
797 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
798 peername);
799 ret = cmd->handler(fd, argc, argv);
800 if (ret >= 0)
801 goto out;
802 err_out:
803 send_va_buffer(fd, "%s\n", para_strerror(-ret));
804 net_err:
805 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
806 out:
807 free(command);
808 free(argv);
809 mmd_lock();
810 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
811 mmd->events++;
812 mmd->active_connections--;
813 mmd_unlock();
814 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
815 }