2 * Copyright (C) 1997-2011 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. */
12 #include <sys/types.h>
20 #include "server.cmdline.h"
32 #include "user_list.h"
33 #include "server_command_list.h"
34 #include "afs_command_list.h"
39 /** Commands including options must be shorter than this. */
40 #define MAX_COMMAND_LEN 32768
43 extern struct misc_meta_data *mmd;
44 extern struct sender senders[];
45 int send_afs_status(struct stream_cipher_context *scc, int parser_friendly);
47 const char *status_item_list[] = {STATUS_ITEM_ARRAY};
49 static void dummy(__a_unused int s)
53 static void mmd_dup(struct misc_meta_data *new_mmd)
55 mutex_lock(mmd_mutex);
57 mutex_unlock(mmd_mutex);
61 * Compute human readable string containing vss status for given integer value.
63 * We don't want to use vss_playing() and friends here because we take a
64 * snapshot of the mmd struct and use the copy for computing the state of the
65 * vss. If the real data were used, we would take the mmd lock for a rather
66 * long time or risk to get an inconsistent view.
68 static char *vss_status_tohuman(unsigned int flags)
70 if (flags & VSS_PLAYING)
71 return para_strdup("playing");
73 return para_strdup("stopped");
74 return para_strdup("paused");
78 * return human readable permission string. Never returns NULL.
80 static char *cmd_perms_itohuman(unsigned int perms)
82 char *msg = para_malloc(5 * sizeof(char));
84 msg[0] = perms & AFS_READ? 'a' : '-';
85 msg[1] = perms & AFS_WRITE? 'A' : '-';
86 msg[2] = perms & VSS_READ? 'v' : '-';
87 msg[3] = perms & VSS_WRITE? 'V' : '-';
95 static char *vss_get_status_flags(unsigned int flags)
97 char *msg = para_malloc(5 * sizeof(char));
99 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
100 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
101 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
102 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
107 static char *get_status(struct misc_meta_data *nmmd, int parser_friendly)
110 char *status, *flags; /* vss status info */
111 /* nobody updates our version of "now" */
112 char *ut = get_server_uptime_str(NULL);
113 long offset = (nmmd->offset + 500) / 1000;
114 struct timeval current_time;
116 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
118 /* report real status */
119 status = vss_status_tohuman(nmmd->vss_status_flags);
120 flags = vss_get_status_flags(nmmd->vss_status_flags);
121 if (nmmd->size) { /* parent currently has an audio file open */
122 localtime_r(&nmmd->mtime, &mtime_tm);
123 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
125 gettimeofday(¤t_time, NULL);
127 * The calls to WRITE_STATUS_ITEM() below never fail because
128 * b->max_size is zero (unlimited), see para_printf(). However, clang
129 * is not smart enough to prove this and complains nevertheless.
130 * Casting the return value to void silences solves this.
132 (void)WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
133 (void)WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
134 (void)WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
135 (void)WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
136 (void)WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
137 (void)WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
138 (void)WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
139 (long unsigned)nmmd->stream_start.tv_sec,
140 (long unsigned)nmmd->stream_start.tv_usec);
141 (void)WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
142 (long unsigned)current_time.tv_sec,
143 (long unsigned)current_time.tv_usec);
150 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
153 /* this has to match sender.h */
154 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
156 scd->sender_num = -1;
158 return -E_COMMAND_SYNTAX;
159 for (i = 0; senders[i].name; i++)
160 if (!strcmp(senders[i].name, argv[1]))
162 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
163 if (!senders[i].name)
164 return -E_COMMAND_SYNTAX;
166 for (i = 0; subcmds[i]; i++)
167 if (!strcmp(subcmds[i], argv[2]))
170 return -E_COMMAND_SYNTAX;
172 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
173 return -E_SENDER_CMD;
174 switch (scd->cmd_num) {
178 return -E_COMMAND_SYNTAX;
182 if (argc != 4 || parse_cidr(argv[3], scd->host,
183 sizeof(scd->host), &scd->netmask) == NULL)
184 return -E_COMMAND_SYNTAX;
189 return -E_COMMAND_SYNTAX;
190 return parse_fec_url(argv[3], scd);
192 return -E_COMMAND_SYNTAX;
197 int com_sender(struct stream_cipher_context *scc, int argc, char * const * argv)
201 struct sender_command_data scd;
204 for (i = 0; senders[i].name; i++) {
205 char *tmp = make_message("%s%s\n",
206 msg? msg : "", senders[i].name);
210 ret = sc_send_buffer(scc, msg);
214 ret = check_sender_args(argc, argv, &scd);
216 if (scd.sender_num < 0)
218 msg = senders[scd.sender_num].help();
219 ret = sc_send_buffer(scc, msg);
224 switch (scd.cmd_num) {
227 assert(senders[scd.sender_num].resolve_target);
228 ret = senders[scd.sender_num].resolve_target(argv[3], &scd);
233 for (i = 0; i < 10; i++) {
234 mutex_lock(mmd_mutex);
235 if (mmd->sender_cmd_data.cmd_num >= 0) {
236 mutex_unlock(mmd_mutex);
240 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
241 mutex_unlock(mmd_mutex);
244 return (i < 10)? 1 : -E_LOCK;
248 int com_si(struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
252 char *sender_info = NULL;
255 return -E_COMMAND_SYNTAX;
256 mutex_lock(mmd_mutex);
257 for (i = 0; senders[i].name; i++) {
258 char *info = senders[i].info();
259 sender_info = para_strcat(sender_info, info);
262 ut = get_server_uptime_str(now);
263 ret = sc_send_va_buffer(scc, "version: " GIT_VERSION "\n"
264 "up: %s\nplayed: %u\n"
267 "connections (active/accepted/total): %u/%u/%u\n"
268 "current loglevel: %s\n"
269 "supported audio formats: %s\n"
274 mmd->active_connections,
278 SERVER_AUDIO_FORMATS,
281 mutex_unlock(mmd_mutex);
288 int com_version(struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
291 return -E_COMMAND_SYNTAX;
292 return sc_send_buffer(scc, VERSION_TEXT("server")
293 "built: " BUILD_DATE "\n"
294 UNAME_RS ", " CC_VERSION "\n"
298 #define EMPTY_STATUS_ITEMS \
303 ITEM(ATTRIBUTES_BITMAP) \
304 ITEM(ATTRIBUTES_TXT) \
315 ITEM(SECONDS_TOTAL) \
327 * Write a list of audio-file related status items with empty values.
329 * This is used by vss when currently no audio file is open.
331 static char *empty_status_items(int parser_friendly)
335 #define ITEM(x) "0004 %02x:\n"
338 #define ITEM(x) , SI_ ## x
343 #define ITEM(x) "%s:\n"
346 #define ITEM(x) ,status_item_list[SI_ ## x]
351 #undef EMPTY_STATUS_ITEMS
354 int com_stat(struct stream_cipher_context *scc, int argc, char * const * argv)
357 struct misc_meta_data tmp, *nmmd = &tmp;
360 int parser_friendly = 0;
362 para_sigaction(SIGUSR1, dummy);
364 for (i = 1; i < argc; i++) {
365 const char *arg = argv[i];
368 if (!strcmp(arg, "--")) {
372 if (!strncmp(arg, "-n=", 3)) {
373 ret = para_atoi32(arg + 3, &num);
378 if (!strcmp(arg, "-p")) {
382 return -E_COMMAND_SYNTAX;
385 return -E_COMMAND_SYNTAX;
388 s = get_status(nmmd, parser_friendly);
389 ret = sc_send_buffer(scc, s);
393 if (nmmd->vss_status_flags & VSS_NEXT) {
396 esi = empty_status_items(parser_friendly);
397 ret = sc_send_buffer(scc, esi);
401 send_afs_status(scc, parser_friendly);
403 if (num > 0 && !--num)
407 return -E_SERVER_CRASH;
413 static int send_list_of_commands(struct stream_cipher_context *scc, struct server_command *cmd,
418 for (i = 1; cmd->name; cmd++, i++) {
419 char *perms = cmd_perms_itohuman(cmd->perms);
420 ret = sc_send_va_buffer(scc, "%s\t%s\t%s\t%s\n", cmd->name,
431 /* returns string that must be freed by the caller */
432 static struct server_command *get_cmd_ptr(const char *name, char **handler)
434 struct server_command *cmd;
436 for (cmd = server_cmds; cmd->name; cmd++)
437 if (!strcmp(cmd->name, name)) {
439 *handler = para_strdup("server"); /* server commands */
442 /* not found, look for commands supported by afs */
443 for (cmd = afs_cmds; cmd->name; cmd++)
444 if (!strcmp(cmd->name, name)) {
446 *handler = para_strdup("afs");
453 int com_help(struct stream_cipher_context *scc, int argc, char * const * argv)
455 struct server_command *cmd;
456 char *perms, *handler;
460 /* no argument given, print list of commands */
461 if ((ret = send_list_of_commands(scc, server_cmds, "server")) < 0)
463 return send_list_of_commands(scc, afs_cmds, "afs");
465 /* argument given for help */
466 cmd = get_cmd_ptr(argv[1], &handler);
469 perms = cmd_perms_itohuman(cmd->perms);
470 ret = sc_send_va_buffer(scc,
489 int com_hup(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
492 return -E_COMMAND_SYNTAX;
493 kill(getppid(), SIGHUP);
498 int com_term(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
501 return -E_COMMAND_SYNTAX;
502 kill(getppid(), SIGTERM);
506 int com_play(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
509 return -E_COMMAND_SYNTAX;
510 mutex_lock(mmd_mutex);
511 mmd->new_vss_status_flags |= VSS_PLAYING;
512 mmd->new_vss_status_flags &= ~VSS_NOMORE;
513 mutex_unlock(mmd_mutex);
519 int com_stop(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
522 return -E_COMMAND_SYNTAX;
523 mutex_lock(mmd_mutex);
524 mmd->new_vss_status_flags &= ~VSS_PLAYING;
525 mmd->new_vss_status_flags &= ~VSS_REPOS;
526 mmd->new_vss_status_flags |= VSS_NEXT;
527 mutex_unlock(mmd_mutex);
532 int com_pause(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
535 return -E_COMMAND_SYNTAX;
536 mutex_lock(mmd_mutex);
537 if (!vss_paused() && !vss_stopped()) {
539 mmd->new_vss_status_flags &= ~VSS_PLAYING;
540 mmd->new_vss_status_flags &= ~VSS_NEXT;
542 mutex_unlock(mmd_mutex);
547 int com_next(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
550 return -E_COMMAND_SYNTAX;
551 mutex_lock(mmd_mutex);
553 mmd->new_vss_status_flags |= VSS_NEXT;
554 mutex_unlock(mmd_mutex);
559 int com_nomore(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
562 return -E_COMMAND_SYNTAX;
563 mutex_lock(mmd_mutex);
564 if (vss_playing() || vss_paused())
565 mmd->new_vss_status_flags |= VSS_NOMORE;
566 mutex_unlock(mmd_mutex);
571 int com_ff(__a_unused struct stream_cipher_context *scc, int argc, char * const * argv)
574 int ret, backwards = 0;
579 return -E_COMMAND_SYNTAX;
580 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
581 return -E_COMMAND_SYNTAX;
582 if (ret > 1 && c == '-')
583 backwards = 1; /* jmp backwards */
584 mutex_lock(mmd_mutex);
585 ret = -E_NO_AUDIO_FILE;
586 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
588 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
590 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
592 promille += 1000 * i / mmd->afd.afhi.seconds_total;
595 if (promille > 1000) {
596 mmd->new_vss_status_flags |= VSS_NEXT;
599 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
600 mmd->new_vss_status_flags |= VSS_REPOS;
601 mmd->new_vss_status_flags &= ~VSS_NEXT;
605 mutex_unlock(mmd_mutex);
610 int com_jmp(__a_unused struct stream_cipher_context *scc, int argc, char * const * argv)
616 return -E_COMMAND_SYNTAX;
617 if (sscanf(argv[1], "%lu", &i) <= 0)
618 return -E_COMMAND_SYNTAX;
619 mutex_lock(mmd_mutex);
620 ret = -E_NO_AUDIO_FILE;
621 if (!mmd->afd.afhi.chunks_total)
625 PARA_INFO_LOG("jumping to %lu%%\n", i);
626 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
627 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
628 mmd->chunks_sent, mmd->offset);
629 mmd->new_vss_status_flags |= VSS_REPOS;
630 mmd->new_vss_status_flags &= ~VSS_NEXT;
634 mutex_unlock(mmd_mutex);
639 * check if perms are sufficient to exec a command having perms cmd_perms.
640 * Returns 0 if perms are sufficient, -E_PERM otherwise.
642 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
644 PARA_DEBUG_LOG("checking permissions\n");
645 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
649 * Parse first string from *cmd and lookup in table of valid commands.
650 * On error, NULL is returned.
652 static struct server_command *parse_cmd(const char *cmdstr)
657 sscanf(cmdstr, "%200s%n", buf, &n);
661 return get_cmd_ptr(buf, NULL);
664 static int read_command(struct stream_cipher_context *scc, char **result)
668 char *command = NULL;
674 ret = sc_recv_buffer(scc, buf, sizeof(buf));
680 ret = -E_COMMAND_SYNTAX;
681 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
683 command = para_strcat(command, buf);
684 p = strstr(command, EOC_MSG);
690 ret = command? 1 : -E_COMMAND_SYNTAX;
700 static void reset_signals(void)
702 para_sigaction(SIGCHLD, SIG_IGN);
703 para_sigaction(SIGINT, SIG_DFL);
704 para_sigaction(SIGTERM, SIG_DFL);
705 para_sigaction(SIGHUP, SIG_DFL);
709 * Perform user authentication and execute a command.
711 * \param fd The file descriptor to send output to.
712 * \param peername Identifies the connecting peer.
714 * Whenever para_server accepts an incoming tcp connection on
715 * the port it listens on, it forks and the resulting child
716 * calls this function.
718 * An RSA-based challenge/response is used to authenticate
719 * the peer. It that authentication succeeds, a random
720 * session key is generated and sent back to the peer,
721 * encrypted with its RSA public key. From this point on,
722 * all transfers are crypted with this session key.
724 * Next it is checked if the peer supplied a valid server command or a command
725 * for the audio file selector. If yes, and if the user has sufficient
726 * permissions to execute that command, the function calls the corresponding
727 * command handler which does argument checking and further processing.
729 * In order to cope with a DOS attacks, a timeout is set up
730 * which terminates the function if the connection was not
731 * authenticated when the timeout expires.
733 * \sa alarm(2), crypt.c, crypt.h
735 __noreturn void handle_connect(int fd, const char *peername)
739 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
740 unsigned char challenge_hash[HASH_SIZE];
742 struct server_command *cmd = NULL;
744 char *p, *command = NULL;
746 struct stream_cipher_context scc = {.fd = fd};
749 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
750 ret = mark_fd_blocking(fd);
753 /* send Welcome message */
754 ret = send_va_buffer(fd, "This is para_server, version "
755 PACKAGE_VERSION ".\n" );
758 /* recv auth request line */
759 ret = recv_buffer(fd, buf, sizeof(buf));
763 ret = -E_AUTH_REQUEST;
766 ret = -E_AUTH_REQUEST;
767 if (strncmp(buf, AUTH_REQUEST_MSG, strlen(AUTH_REQUEST_MSG)))
769 p = buf + strlen(AUTH_REQUEST_MSG);
770 PARA_DEBUG_LOG("received auth request for user %s\n", p);
773 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
774 ret = pub_encrypt(u->pubkey, rand_buf, sizeof(rand_buf),
775 (unsigned char *)buf);
781 * We don't want to reveal our user names, so we send a
782 * challenge to the client even if the user does not exist, and
783 * fail the authentication later.
786 get_random_bytes_or_die((unsigned char *)buf, numbytes);
788 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
789 CHALLENGE_SIZE, numbytes);
790 ret = send_bin_buffer(fd, buf, numbytes);
793 /* recv challenge response */
794 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
798 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret);
803 * The correct response is the hash of the first CHALLENGE_SIZE bytes
804 * of the random data.
807 if (numbytes != HASH_SIZE)
809 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
810 if (memcmp(challenge_hash, buf, HASH_SIZE))
812 /* auth successful */
814 PARA_INFO_LOG("good auth for %s\n", u->name);
815 /* init stream cipher keys with the second part of the random buffer */
816 scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
817 scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN, SESSION_KEY_LEN);
818 ret = sc_send_buffer(&scc, PROCEED_MSG);
821 ret = read_command(&scc, &command);
822 if (ret == -E_COMMAND_SYNTAX)
827 cmd = parse_cmd(command);
830 /* valid command, check permissions */
831 ret = check_perms(u->perms, cmd);
834 /* valid command and sufficient perms */
835 ret = create_argv(command, "\n", &argv);
839 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
841 ret = cmd->handler(&scc, argc, argv);
843 mutex_lock(mmd_mutex);
845 mutex_unlock(mmd_mutex);
849 sc_send_va_buffer(&scc, "%s\n", para_strerror(-ret));
851 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
856 mutex_lock(mmd_mutex);
857 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
859 mmd->active_connections--;
860 mutex_unlock(mmd_mutex);
861 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);