b59fae7af154d5545999ae6b79757c06b7c118ee
[paraslash.git] / command.c
1 /*
2 * Copyright (C) 1997-2009 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 "ipc.h"
30 #include "user_list.h"
31 #include "server_command_list.h"
32 #include "afs_command_list.h"
33
34 /** Commands including options must be shorter than this. */
35 #define MAX_COMMAND_LEN 32768
36
37 static RC4_KEY rc4_recv_key;
38 static RC4_KEY rc4_send_key;
39 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
40
41 extern int mmd_mutex;
42 extern struct misc_meta_data *mmd;
43 extern struct sender senders[];
44
45 static void dummy(int s)
46 {
47 /*
48 * At least on Solaris, SIGUSR1 is one-shot, i.e. the signal action is
49 * restored to the default state once the signal handler has been
50 * called.
51 */
52 if (s == SIGUSR1)
53 signal(SIGUSR1, dummy);
54 }
55
56 static void mmd_dup(struct misc_meta_data *new_mmd)
57 {
58 mutex_lock(mmd_mutex);
59 *new_mmd = *mmd;
60 mutex_unlock(mmd_mutex);
61 }
62
63 /*
64 * Compute human readable string containing vss status for given integer value.
65 *
66 * We don't want to use vss_playing() and friends here because we take a
67 * snapshot of the mmd struct and use the copy for computing the state of the
68 * vss. If the real data were used, we would take the mmd lock for a rather
69 * long time or risk to get an inconsistent view.
70 */
71 static char *vss_status_tohuman(unsigned int flags)
72 {
73 if (flags & VSS_PLAYING)
74 return para_strdup("playing");
75 if (flags & VSS_NEXT)
76 return para_strdup("stopped");
77 return para_strdup("paused");
78 }
79
80 /*
81 * return human readable permission string. Never returns NULL.
82 */
83 static char *cmd_perms_itohuman(unsigned int perms)
84 {
85 char *msg = para_malloc(5 * sizeof(char));
86
87 msg[0] = perms & AFS_READ? 'a' : '-';
88 msg[1] = perms & AFS_WRITE? 'A' : '-';
89 msg[2] = perms & VSS_READ? 'v' : '-';
90 msg[3] = perms & VSS_WRITE? 'V' : '-';
91 msg[4] = '\0';
92 return msg;
93 }
94
95 /*
96 * Never returns NULL.
97 */
98 static char *vss_get_status_flags(unsigned int flags)
99 {
100 char *msg = para_malloc(5 * sizeof(char));
101
102 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
103 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
104 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
105 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
106 msg[4] = '\0';
107 return msg;
108 }
109
110 static char *get_status(struct misc_meta_data *nmmd)
111 {
112 char *ret, mtime[30] = "";
113 char *status, *flags; /* vss status info */
114 char *ut = uptime_str();
115 long offset = (nmmd->offset + 500) / 1000;
116 struct timeval now;
117 struct tm mtime_tm;
118
119 /* report real status */
120 status = vss_status_tohuman(nmmd->vss_status_flags);
121 flags = vss_get_status_flags(nmmd->vss_status_flags);
122 if (nmmd->size) { /* parent currently has an audio file open */
123 localtime_r(&nmmd->mtime, &mtime_tm);
124 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
125 }
126 gettimeofday(&now, NULL);
127 ret = make_message(
128 "%s: %zu\n" /* file size */
129 "%s: %s\n" /* mtime */
130 "%s: %s\n" /* status */
131 "%s: %s\n" /* status flags */
132 "%s: %li\n" /* offset */
133 "%s: %s\n" /* afs mode */
134 "%s: %lu.%lu\n" /* stream start */
135 "%s: %lu.%lu\n" /* current server time */
136 "%s", /* afs status info */
137 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
138 status_item_list[SI_MTIME], mtime,
139 status_item_list[SI_STATUS], status,
140 status_item_list[SI_STATUS_FLAGS], flags,
141
142 status_item_list[SI_OFFSET], offset,
143 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
144
145 status_item_list[SI_STREAM_START],
146 (long unsigned)nmmd->stream_start.tv_sec,
147 (long unsigned)nmmd->stream_start.tv_usec,
148 status_item_list[SI_CURRENT_TIME],
149 (long unsigned)now.tv_sec,
150 (long unsigned)now.tv_usec,
151
152 nmmd->afd.verbose_ls_output
153
154 );
155 free(flags);
156 free(status);
157 free(ut);
158 return ret;
159 }
160
161 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
162 {
163 int i;
164 /* this has to match sender.h */
165 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
166
167 scd->sender_num = -1;
168 if (argc < 2)
169 return -E_COMMAND_SYNTAX;
170 for (i = 0; senders[i].name; i++)
171 if (!strcmp(senders[i].name, argv[1]))
172 break;
173 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
174 if (!senders[i].name)
175 return -E_COMMAND_SYNTAX;
176 scd->sender_num = i;
177 for (i = 0; subcmds[i]; i++)
178 if (!strcmp(subcmds[i], argv[2]))
179 break;
180 if (!subcmds[i])
181 return -E_COMMAND_SYNTAX;
182 scd->cmd_num = i;
183 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
184 return -E_SENDER_CMD;
185 switch (scd->cmd_num) {
186 case SENDER_ON:
187 case SENDER_OFF:
188 if (argc != 3)
189 return -E_COMMAND_SYNTAX;
190 break;
191 case SENDER_DENY:
192 case SENDER_ALLOW:
193 if (argc != 4 && argc != 5)
194 return -E_COMMAND_SYNTAX;
195 if (!is_valid_ipv4_address(argv[3]))
196 return -E_COMMAND_SYNTAX;
197 scd->netmask = 32;
198 if (argc == 5) {
199 scd->netmask = atoi(argv[4]);
200 if (scd->netmask < 0 || scd->netmask > 32)
201 return -E_COMMAND_SYNTAX;
202 }
203 strncpy(scd->host, argv[3], sizeof(scd->host));
204 break;
205 case SENDER_ADD:
206 case SENDER_DELETE:
207 if (argc != 4)
208 return -E_COMMAND_SYNTAX;
209 return parse_fec_url(argv[3], scd);
210 default:
211 return -E_COMMAND_SYNTAX;
212 }
213 return 1;
214 }
215
216 int com_sender(int fd, int argc, char * const * argv)
217 {
218 int i, ret;
219 struct sender_command_data scd;
220
221 if (argc < 2) {
222 char *msg = NULL;
223 for (i = 0; senders[i].name; i++) {
224 char *tmp = make_message("%s%s\n",
225 msg? msg : "", senders[i].name);
226 free(msg);
227 msg = tmp;
228 }
229 ret = send_buffer(fd, msg);
230 free(msg);
231 return ret;
232 }
233 ret = check_sender_args(argc, argv, &scd);
234 if (ret < 0) {
235 char *msg;
236 if (scd.sender_num < 0)
237 return ret;
238 msg = senders[scd.sender_num].help();
239 ret = send_buffer(fd, msg);
240 free(msg);
241 return ret;
242 }
243 for (i = 0; i < 10; i++) {
244 mutex_lock(mmd_mutex);
245 if (mmd->sender_cmd_data.cmd_num >= 0) {
246 mutex_unlock(mmd_mutex);
247 usleep(100 * 1000);
248 continue;
249 }
250 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
251 mutex_unlock(mmd_mutex);
252 break;
253 }
254 return (i < 10)? 1 : -E_LOCK;
255 }
256
257 /* server info */
258 int com_si(int fd, int argc, __a_unused char * const * argv)
259 {
260 int i, ret;
261 char *ut;
262 char *sender_info = NULL, *sender_list = NULL;
263
264 if (argc != 1)
265 return -E_COMMAND_SYNTAX;
266 mutex_lock(mmd_mutex);
267 for (i = 0; senders[i].name; i++) {
268 char *info = senders[i].info();
269 sender_info = para_strcat(sender_info, info);
270 free(info);
271 sender_list = para_strcat(sender_list, senders[i].name);
272 sender_list = para_strcat(sender_list, " ");
273 }
274 ut = uptime_str();
275 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
276 "server_pid: %d\n"
277 "afs_pid: %d\n"
278 "connections (active/accepted/total): %u/%u/%u\n"
279 "current loglevel: %s\n"
280 "supported audio formats: %s\n"
281 "supported senders: %s\n"
282 "%s",
283 ut, mmd->num_played,
284 (int)getppid(),
285 (int)mmd->afs_pid,
286 mmd->active_connections,
287 mmd->num_commands,
288 mmd->num_connects,
289 conf.loglevel_arg,
290 supported_audio_formats(),
291 sender_list,
292 sender_info
293 );
294 mutex_unlock(mmd_mutex);
295 free(ut);
296 free(sender_list);
297 free(sender_info);
298 return ret;
299 }
300
301 /* version */
302 int com_version(int fd, int argc, __a_unused char * const * argv)
303 {
304 if (argc != 1)
305 return -E_COMMAND_SYNTAX;
306 return send_buffer(fd, VERSION_TEXT("server")
307 "built: " BUILD_DATE "\n"
308 UNAME_RS ", " CC_VERSION "\n"
309 );
310 }
311
312 /* stat */
313 int com_stat(int fd, int argc, char * const * argv)
314 {
315 int ret, num = 0;/* status will be printed that many
316 * times. num <= 0 means: print forever
317 */
318 struct misc_meta_data tmp, *nmmd = &tmp;
319 char *s;
320
321 signal(SIGUSR1, dummy);
322
323 if (argc > 1)
324 num = atoi(argv[1]);
325 for (;;) {
326
327 mmd_dup(nmmd);
328 s = get_status(nmmd);
329 ret = send_buffer(fd, s);
330 free(s);
331 if (ret < 0)
332 goto out;
333 ret = 1;
334 if (num > 0 && !--num)
335 goto out;
336 sleep(50);
337 if (getppid() == 1)
338 return -E_SERVER_CRASH;
339 }
340 out:
341 return ret;
342 }
343
344 static int send_list_of_commands(int fd, struct server_command *cmd,
345 const char *handler)
346 {
347 int ret, i;
348
349 for (i = 1; cmd->name; cmd++, i++) {
350 char *perms = cmd_perms_itohuman(cmd->perms);
351 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
352 handler,
353 perms,
354 cmd->description);
355 free(perms);
356 if (ret < 0)
357 return ret;
358 }
359 return 1;
360 }
361
362 /* returns string that must be freed by the caller */
363 static struct server_command *get_cmd_ptr(const char *name, char **handler)
364 {
365 struct server_command *cmd;
366
367 for (cmd = server_cmds; cmd->name; cmd++)
368 if (!strcmp(cmd->name, name)) {
369 if (handler)
370 *handler = para_strdup("server"); /* server commands */
371 return cmd;
372 }
373 /* not found, look for commands supported by afs */
374 for (cmd = afs_cmds; cmd->name; cmd++)
375 if (!strcmp(cmd->name, name)) {
376 if (handler)
377 *handler = para_strdup("afs");
378 return cmd;
379 }
380 return NULL;
381 }
382
383 /* help */
384 int com_help(int fd, int argc, char * const * argv)
385 {
386 struct server_command *cmd;
387 char *perms, *handler;
388 int ret;
389
390 if (argc < 2) {
391 /* no argument given, print list of commands */
392 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
393 return ret;
394 return send_list_of_commands(fd, afs_cmds, "afs");
395 }
396 /* argument given for help */
397 cmd = get_cmd_ptr(argv[1], &handler);
398 if (!cmd) {
399 free(handler);
400 return -E_BAD_CMD;
401 }
402 perms = cmd_perms_itohuman(cmd->perms);
403 ret = send_va_buffer(fd,
404 "%s - %s\n\n"
405 "handler: %s\n"
406 "permissions: %s\n"
407 "usage: %s\n\n"
408 "%s\n",
409 argv[1],
410 cmd->description,
411 handler,
412 perms,
413 cmd->usage,
414 cmd->help
415 );
416 free(perms);
417 free(handler);
418 return ret;
419 }
420
421 /* hup */
422 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
423 {
424 if (argc != 1)
425 return -E_COMMAND_SYNTAX;
426 kill(getppid(), SIGHUP);
427 return 1;
428 }
429
430 /* term */
431 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
432 {
433 if (argc != 1)
434 return -E_COMMAND_SYNTAX;
435 kill(getppid(), SIGTERM);
436 return 1;
437 }
438
439 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
440 {
441 if (argc != 1)
442 return -E_COMMAND_SYNTAX;
443 mutex_lock(mmd_mutex);
444 mmd->new_vss_status_flags |= VSS_PLAYING;
445 mmd->new_vss_status_flags &= ~VSS_NOMORE;
446 mutex_unlock(mmd_mutex);
447 return 1;
448
449 }
450
451 /* stop */
452 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
453 {
454 if (argc != 1)
455 return -E_COMMAND_SYNTAX;
456 mutex_lock(mmd_mutex);
457 mmd->new_vss_status_flags &= ~VSS_PLAYING;
458 mmd->new_vss_status_flags &= ~VSS_REPOS;
459 mmd->new_vss_status_flags |= VSS_NEXT;
460 mutex_unlock(mmd_mutex);
461 return 1;
462 }
463
464 /* pause */
465 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
466 {
467 if (argc != 1)
468 return -E_COMMAND_SYNTAX;
469 mutex_lock(mmd_mutex);
470 if (!vss_paused() && !vss_stopped()) {
471 mmd->events++;
472 mmd->new_vss_status_flags &= ~VSS_PLAYING;
473 mmd->new_vss_status_flags &= ~VSS_NEXT;
474 }
475 mutex_unlock(mmd_mutex);
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 mutex_lock(mmd_mutex);
485 mmd->events++;
486 mmd->new_vss_status_flags |= VSS_NEXT;
487 mutex_unlock(mmd_mutex);
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 mutex_lock(mmd_mutex);
497 if (vss_playing() || vss_paused())
498 mmd->new_vss_status_flags |= VSS_NOMORE;
499 mutex_unlock(mmd_mutex);
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 mutex_lock(mmd_mutex);
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 mutex_unlock(mmd_mutex);
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 mutex_lock(mmd_mutex);
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 mutex_unlock(mmd_mutex);
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("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 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_random(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 peername Identifies the connecting peer.
663 *
664 * Whenever para_server accepts an incoming tcp connection on
665 * the port it listens on, it forks and the resulting child
666 * calls this function.
667 *
668 * An RSA-based challenge/response is used to authenticate
669 * the peer. It that authentication succeeds, a random RC4
670 * session key is generated and sent back to the peer,
671 * encrypted with its RSA public key. From this point on,
672 * all transfers are crypted with this session key.
673 *
674 * Next it is checked if the peer supplied a valid server command or a command
675 * for the audio file selector. If yes, and if the user has sufficient
676 * permissions to execute that command, the function calls the corresponding
677 * command handler which does argument checking and further processing.
678 *
679 * In order to cope with a DOS attacks, a timeout is set up
680 * which terminates the function if the connection was not
681 * authenticated when the timeout expires.
682 *
683 * \sa alarm(2), rc4(3), crypt.c, crypt.h
684 */
685 __noreturn void handle_connect(int fd, const char *peername)
686 {
687 int ret, argc, use_rc4 = 0;
688 char buf[4096];
689 unsigned char crypt_buf[MAXLINE];
690 struct user *u;
691 struct server_command *cmd = NULL;
692 long unsigned challenge_nr, chall_response;
693 char **argv = NULL;
694 char *p, *command = NULL;
695 size_t numbytes;
696
697 signal(SIGCHLD, SIG_IGN);
698 signal(SIGINT, SIG_DFL);
699 signal(SIGTERM, SIG_DFL);
700 signal(SIGHUP, SIG_DFL);
701
702 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
703 ret = mark_fd_blocking(fd);
704 if (ret < 0)
705 goto err_out;
706 challenge_nr = random();
707 /* send Welcome message */
708 ret = send_va_buffer(fd, "This is para_server, version "
709 PACKAGE_VERSION ".\n" );
710 if (ret < 0)
711 goto err_out;
712 /* recv auth request line */
713 ret = recv_buffer(fd, buf, sizeof(buf));
714 if (ret < 0)
715 goto err_out;
716 if (ret <= 6) {
717 ret = -E_AUTH;
718 goto err_out;
719 }
720 numbytes = ret;
721 ret = -E_AUTH;
722 if (strncmp(buf, "auth ", 5))
723 goto err_out;
724
725 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
726 p = buf + 5; /* client version < 0.2.6 */
727 else {
728 p = buf + 9; /* client version >= 0.2.6 */
729 use_rc4 = 1;
730 }
731 PARA_DEBUG_LOG("received %s request for user %s\n",
732 use_rc4? "rc4" : "auth", p);
733 ret = -E_BAD_USER;
734 u = lookup_user(p);
735 if (!u)
736 goto err_out;
737 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
738 if (ret <= 0)
739 goto err_out;
740 numbytes = ret;
741 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
742 /* We can't use send_buffer here since buf may contain null bytes */
743 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
744 if (ret < 0)
745 goto net_err;
746 /* recv decrypted number */
747 ret = recv_buffer(fd, buf, sizeof(buf));
748 if (ret < 0)
749 goto net_err;
750 numbytes = ret;
751 ret = -E_AUTH;
752 if (!numbytes)
753 goto net_err;
754 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
755 || chall_response != challenge_nr)
756 goto err_out;
757 /* auth successful, send 'Proceed' message */
758 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
759 sprintf(buf, "%s", PROCEED_MSG);
760 if (use_rc4) {
761 init_rc4_keys();
762 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
763 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
764 if (ret <= 0)
765 goto err_out;
766 numbytes = ret + strlen(PROCEED_MSG) + 1;
767 } else
768 numbytes = strlen(buf);
769 ret = send_bin_buffer(fd, buf, numbytes);
770 if (ret < 0)
771 goto net_err;
772 if (use_rc4)
773 enable_crypt(fd, rc4_recv, rc4_send, NULL);
774 ret = read_command(fd, &command);
775 if (ret == -E_COMMAND_SYNTAX)
776 goto err_out;
777 if (ret < 0)
778 goto net_err;
779 ret = -E_BAD_CMD;
780 cmd = parse_cmd(command);
781 if (!cmd)
782 goto err_out;
783 /* valid command, check permissions */
784 ret = check_perms(u->perms, cmd);
785 if (ret < 0)
786 goto err_out;
787 /* valid command and sufficient perms */
788 alarm(0);
789 argc = split_args(command, &argv, "\n");
790 mutex_lock(mmd_mutex);
791 mmd->num_commands++;
792 mutex_unlock(mmd_mutex);
793 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
794 peername);
795 ret = cmd->handler(fd, argc, argv);
796 if (ret >= 0)
797 goto out;
798 err_out:
799 send_va_buffer(fd, "%s\n", para_strerror(-ret));
800 net_err:
801 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
802 out:
803 free(command);
804 free(argv);
805 mutex_lock(mmd_mutex);
806 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
807 mmd->events++;
808 mmd->active_connections--;
809 mutex_unlock(mmd_mutex);
810 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
811 }