2 * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file command.c Client authentication and server commands. */
11 #include <sys/types.h>
13 #include <openssl/rc4.h>
17 #include "server.cmdline.h"
29 #include "user_list.h"
30 #include "server_command_list.h"
31 #include "afs_command_list.h"
33 /** Commands including options must be shorter than this. */
34 #define MAX_COMMAND_LEN 32768
36 static RC4_KEY rc4_recv_key;
37 static RC4_KEY rc4_send_key;
38 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
40 extern const char *status_item_list[NUM_STAT_ITEMS];
41 extern struct misc_meta_data *mmd;
42 extern struct sender senders[];
44 static void dummy(__a_unused int s)
47 static void mmd_dup(struct misc_meta_data *new_mmd)
55 * compute human readable string containing
56 * vss status for given integer value
58 static char *vss_status_tohuman(unsigned int flags)
60 if (flags & VSS_PLAYING)
61 return para_strdup("playing");
62 else if (flags & VSS_NEXT)
63 return para_strdup("stopped");
65 return para_strdup("paused");
69 * return human readable permission string. Never returns NULL.
71 static char *cmd_perms_itohuman(unsigned int perms)
73 char *msg = para_malloc(5 * sizeof(char));
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' : '-';
86 static char *vss_get_status_flags(unsigned int flags)
88 char *msg = para_malloc(5 * sizeof(char));
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' : '_';
98 static char *get_status(struct misc_meta_data *nmmd)
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;
107 /* report real status */
108 status = vss_status_tohuman(nmmd->vss_status_flags);
109 flags = vss_get_status_flags(nmmd->vss_status_flags);
110 basename = para_basename(nmmd->afd.path);
111 dirname = para_dirname(nmmd->afd.path);
113 localtime_r(&nmmd->mtime, &mtime_tm);
114 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
116 gettimeofday(&now, NULL);
118 "%s:%zu\n" "%s:%s\n" "%s:%lu\n" "%s:%u\n"
119 "%s:%s\n" "%s:%s\n" "%s:%s\n" "%s:%u\n"
120 "%s:%li\n" "%s:%s\n" "%s:%s\n" "%s"
121 "%s:%s\n" "%s:%lu.%lu\n" "%s:%lu.%lu\n" "%s:%s\n"
122 "%s:%s\n" "%s:%u\n" "%s\n",
123 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
124 status_item_list[SI_MTIME], mtime,
125 status_item_list[SI_LENGTH], nmmd->afd.afhi.seconds_total,
126 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
128 status_item_list[SI_BASENAME], basename ? basename : "(none)",
129 status_item_list[SI_STATUS], status,
130 status_item_list[SI_STATUS_FLAGS], flags,
131 status_item_list[SI_IMAGE_ID], nmmd->afd.afsi.image_id,
133 status_item_list[SI_OFFSET], offset,
134 status_item_list[SI_FORMAT], basename?
135 audio_format_name(nmmd->afd.afsi.audio_format_id)
137 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
138 nmmd->afd.afhi.info_string,
140 status_item_list[SI_UPTIME], ut,
141 status_item_list[SI_STREAM_START],
142 (long unsigned)nmmd->stream_start.tv_sec,
143 (long unsigned)nmmd->stream_start.tv_usec,
144 status_item_list[SI_CURRENT_TIME],
145 (long unsigned)now.tv_sec,
146 (long unsigned)now.tv_usec,
147 status_item_list[SI_ATTRIBUTES], mmd->afd.attributes_string,
149 status_item_list[SI_DIRECTORY], dirname? dirname : "(none)",
150 status_item_list[SI_LYRICS_ID], nmmd->afd.afsi.lyrics_id,
151 nmmd->afd.afs_status_info
162 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
165 /* this has to match sender.h */
166 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
168 scd->sender_num = -1;
170 return -E_COMMAND_SYNTAX;
171 for (i = 0; senders[i].name; i++)
172 if (!strcmp(senders[i].name, argv[1]))
174 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
175 if (!senders[i].name)
176 return -E_COMMAND_SYNTAX;
178 for (i = 0; subcmds[i]; i++)
179 if (!strcmp(subcmds[i], argv[2]))
182 return -E_COMMAND_SYNTAX;
185 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
187 return -E_SENDER_CMD;
190 switch (scd->cmd_num) {
194 return -E_COMMAND_SYNTAX;
198 if (argc != 4 && argc != 5)
199 return -E_COMMAND_SYNTAX;
200 if (!inet_pton(AF_INET, argv[3], &scd->addr))
201 return -E_COMMAND_SYNTAX;
204 scd->netmask = atoi(argv[4]);
205 if (scd->netmask < 0 || scd->netmask > 32)
206 return -E_COMMAND_SYNTAX;
211 if (argc != 4 && argc != 5)
212 return -E_COMMAND_SYNTAX;
213 if (!inet_pton(AF_INET, argv[3], &scd->addr))
214 return -E_COMMAND_SYNTAX;
217 scd->port = atoi(argv[4]);
218 if (scd->port < 0 || scd->port > 65535)
219 return -E_COMMAND_SYNTAX;
223 return -E_COMMAND_SYNTAX;
228 int com_sender(int fd, int argc, char * const * argv)
231 struct sender_command_data scd;
235 for (i = 0; senders[i].name; i++) {
236 char *tmp = make_message("%s%s\n",
237 msg? msg : "", senders[i].name);
241 ret = send_buffer(fd, msg);
245 ret = check_sender_args(argc, argv, &scd);
248 if (scd.sender_num < 0)
250 msg = senders[scd.sender_num].help();
251 send_buffer(fd, msg);
255 for (i = 0; i < 10; i++) {
257 if (mmd->sender_cmd_data.cmd_num >= 0) {
262 mmd->sender_cmd_data = scd;
266 return (i < 10)? 1 : -E_LOCK;
270 int com_si(int fd, int argc, __a_unused char * const * argv)
274 char *sender_info = NULL, *sender_list = NULL;
277 return -E_COMMAND_SYNTAX;
279 for (i = 0; senders[i].name; i++) {
280 char *info = senders[i].info();
281 sender_info = para_strcat(sender_info, info);
283 sender_list = para_strcat(sender_list, senders[i].name);
284 sender_list = para_strcat(sender_list, " ");
287 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
289 "connections (active/accepted/total): %u/%u/%u\n"
290 "current loglevel: %i\n"
291 "supported audio formats: %s\n"
292 "supported senders: %s\n"
296 mmd->active_connections,
300 supported_audio_formats(),
312 int com_version(int fd, int argc, __a_unused char * const * argv)
315 return -E_COMMAND_SYNTAX;
316 return send_buffer(fd, VERSION_TEXT("server")
317 "built: " BUILD_DATE "\n"
318 SYSTEM ", " CC_VERSION "\n"
323 int com_stat(int fd, int argc, char * const * argv)
325 int ret, num = 0;/* status will be printed that many
326 * times. num <= 0 means: print forever
328 struct misc_meta_data tmp, *nmmd = &tmp;
331 signal(SIGUSR1, dummy);
338 s = get_status(nmmd);
339 ret = send_buffer(fd, s);
348 return -E_SERVER_CRASH;
354 static int send_list_of_commands(int fd, struct server_command *cmd,
359 for (i = 1; cmd->name; cmd++, i++) {
360 char *perms = cmd_perms_itohuman(cmd->perms);
361 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
372 /* returns string that must be freed by the caller */
373 static struct server_command *get_cmd_ptr(const char *name, char **handler)
375 struct server_command *cmd;
377 for (cmd = server_cmds; cmd->name; cmd++)
378 if (!strcmp(cmd->name, name)) {
380 *handler = para_strdup("server"); /* server commands */
383 /* not found, look for commands supported by afs */
384 for (cmd = afs_cmds; cmd->name; cmd++)
385 if (!strcmp(cmd->name, name)) {
387 *handler = para_strdup("afs");
394 int com_help(int fd, int argc, char * const * argv)
396 struct server_command *cmd;
397 char *perms, *handler;
401 /* no argument given, print list of commands */
402 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
404 return send_list_of_commands(fd, afs_cmds, "afs");
406 /* argument given for help */
407 cmd = get_cmd_ptr(argv[1], &handler);
412 perms = cmd_perms_itohuman(cmd->perms);
413 ret = send_va_buffer(fd,
432 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
435 return -E_COMMAND_SYNTAX;
436 kill(getppid(), SIGHUP);
441 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
444 return -E_COMMAND_SYNTAX;
445 kill(getppid(), SIGTERM);
449 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
452 return -E_COMMAND_SYNTAX;
454 mmd->new_vss_status_flags |= VSS_PLAYING;
455 mmd->new_vss_status_flags &= ~VSS_NOMORE;
462 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
465 return -E_COMMAND_SYNTAX;
467 mmd->new_vss_status_flags &= ~VSS_PLAYING;
468 mmd->new_vss_status_flags &= ~VSS_REPOS;
469 mmd->new_vss_status_flags |= VSS_NEXT;
475 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
478 return -E_COMMAND_SYNTAX;
482 mmd->new_vss_status_flags &= ~VSS_PLAYING;
483 mmd->new_vss_status_flags &= ~VSS_NEXT;
489 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
492 return -E_COMMAND_SYNTAX;
495 mmd->new_vss_status_flags |= VSS_NEXT;
501 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
504 return -E_COMMAND_SYNTAX;
506 if (vss_playing() || vss_paused())
507 mmd->new_vss_status_flags |= VSS_NOMORE;
513 int com_ff(__a_unused int fd, int argc, char * const * argv)
516 int ret, backwards = 0;
521 return -E_COMMAND_SYNTAX;
522 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
523 return -E_COMMAND_SYNTAX;
524 if (ret > 1 && c == '-')
525 backwards = 1; /* jmp backwards */
527 ret = -E_NO_AUDIO_FILE;
528 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
530 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
532 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
534 promille += 1000 * i / mmd->afd.afhi.seconds_total;
537 if (promille > 1000) {
538 mmd->new_vss_status_flags |= VSS_NEXT;
541 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
542 mmd->new_vss_status_flags |= VSS_REPOS;
543 mmd->new_vss_status_flags &= ~VSS_NEXT;
552 int com_jmp(__a_unused int fd, int argc, char * const * argv)
558 return -E_COMMAND_SYNTAX;
559 if (sscanf(argv[1], "%lu", &i) <= 0)
560 return -E_COMMAND_SYNTAX;
562 ret = -E_NO_AUDIO_FILE;
563 if (!mmd->afd.afhi.chunks_total)
567 PARA_INFO_LOG("jumping to %lu%%\n", i);
568 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
569 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
570 mmd->chunks_sent, mmd->offset);
571 mmd->new_vss_status_flags |= VSS_REPOS;
572 mmd->new_vss_status_flags &= ~VSS_NEXT;
581 * check if perms are sufficient to exec a command having perms cmd_perms.
582 * Returns 0 if perms are sufficient, -E_PERM otherwise.
584 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
586 PARA_DEBUG_LOG("%s", "checking permissions\n");
587 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
591 * Parse first string from *cmd and lookup in table of valid commands.
592 * On error, NULL is returned.
594 static struct server_command *parse_cmd(const char *cmdstr)
599 sscanf(cmdstr, "%200s%n", buf, &n);
603 return get_cmd_ptr(buf, NULL);
606 static void init_rc4_keys(void)
610 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
611 rc4_buf[i] = para_random(256);
612 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
613 (unsigned char) rc4_buf[0],
614 (unsigned char) rc4_buf[RC4_KEY_LEN]);
615 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
616 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
619 static void rc4_recv(unsigned long len, const unsigned char *indata,
620 unsigned char *outdata, __a_unused void *private_data)
622 RC4(&rc4_recv_key, len, indata, outdata);
625 static void rc4_send(unsigned long len, const unsigned char *indata,
626 unsigned char *outdata, __a_unused void *private_data)
628 RC4(&rc4_send_key, len, indata, outdata);
631 static int read_command(int fd, char **result)
635 char *command = NULL;
641 ret = recv_buffer(fd, buf, sizeof(buf));
647 ret = -E_COMMAND_SYNTAX;
648 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
650 command = para_strcat(command, buf);
651 p = strstr(command, EOC_MSG);
657 ret = command? 1 : -E_COMMAND_SYNTAX;
668 * perform user authentication and execute a command
670 * \param fd the file descriptor to send output to
671 * \param addr socket address info of peer
673 * \return EXIT_SUCCESS or EXIT_FAILURE
675 * Whenever para_server accepts an incoming tcp connection on
676 * the port it listens on, it forks and the resulting child
677 * calls this function.
679 * An RSA-based challenge/response is used to authenticate
680 * the peer. It that authentication succeeds, a random RC4
681 * session key is generated and sent back to the peer,
682 * encrypted with its RSA public key. From this point on,
683 * all transfers are crypted with this session key.
685 * Next it is checked if the peer supplied a valid server command or a command
686 * for the audio file selector. If yes, and if the user has sufficient
687 * permissions to execute that command, the function calls the corresponding
688 * command handler which does argument checking and further processing.
690 * In order to cope with a DOS attacks, a timeout is set up
691 * which terminates the function if the connection was not
692 * authenticated when the timeout expires.
694 * \sa alarm(2), rc4(3), crypt.c, crypt.h
696 int handle_connect(int fd, struct sockaddr_in *addr)
698 int ret, argc, use_rc4 = 0;
700 unsigned char crypt_buf[MAXLINE];
702 struct server_command *cmd = NULL;
703 long unsigned challenge_nr, chall_response;
705 char *p, *command = NULL;
708 signal(SIGCHLD, SIG_IGN);
709 signal(SIGINT, SIG_DFL);
710 signal(SIGTERM, SIG_DFL);
711 signal(SIGHUP, SIG_DFL);
712 signal(SIGUSR1, SIG_IGN);
714 challenge_nr = random();
715 /* send Welcome message */
716 ret = send_va_buffer(fd, "This is para_server, version "
717 PACKAGE_VERSION ".\n" );
720 /* recv auth request line */
721 ret = recv_buffer(fd, buf, sizeof(buf));
730 if (strncmp(buf, "auth ", 5))
733 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
734 p = buf + 5; /* client version < 0.2.6 */
736 p = buf + 9; /* client version >= 0.2.6 */
739 PARA_DEBUG_LOG("received %s request for user %s\n",
740 use_rc4? "rc4" : "auth", p);
745 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
749 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
750 /* We can't use send_buffer here since buf may contain null bytes */
751 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
754 /* recv decrypted number */
755 ret = recv_buffer(fd, buf, sizeof(buf));
762 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
763 || chall_response != challenge_nr)
765 /* auth successful, send 'Proceed' message */
766 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
767 sprintf(buf, "%s", PROCEED_MSG);
770 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
771 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
774 numbytes = ret + strlen(PROCEED_MSG) + 1;
776 numbytes = strlen(buf);
777 ret = send_bin_buffer(fd, buf, numbytes);
781 enable_crypt(fd, rc4_recv, rc4_send, NULL);
782 ret = read_command(fd, &command);
786 cmd = parse_cmd(command);
789 /* valid command, check permissions */
790 ret = check_perms(u->perms, cmd);
793 /* valid command and sufficient perms */
795 argc = split_args(command, &argv, "\n");
799 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
800 inet_ntoa(addr->sin_addr));
801 ret = cmd->handler(fd, argc, argv);
807 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
808 if (ret != -E_SEND && ret != -E_RECV)
809 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
815 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
817 mmd->active_connections--;