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"
38 /** Commands including options must be shorter than this. */
39 #define MAX_COMMAND_LEN 32768
42 extern struct misc_meta_data *mmd;
43 extern struct sender senders[];
44 int send_afs_status(struct stream_cipher_context *scc, int parser_friendly);
46 const char *status_item_list[] = {STATUS_ITEM_ARRAY};
48 static void dummy(__a_unused int s)
52 static void mmd_dup(struct misc_meta_data *new_mmd)
54 mutex_lock(mmd_mutex);
56 mutex_unlock(mmd_mutex);
60 * Compute human readable string containing vss status for given integer value.
62 * We don't want to use vss_playing() and friends here because we take a
63 * snapshot of the mmd struct and use the copy for computing the state of the
64 * vss. If the real data were used, we would take the mmd lock for a rather
65 * long time or risk to get an inconsistent view.
67 static char *vss_status_tohuman(unsigned int flags)
69 if (flags & VSS_PLAYING)
70 return para_strdup("playing");
72 return para_strdup("stopped");
73 return para_strdup("paused");
77 * return human readable permission string. Never returns NULL.
79 static char *cmd_perms_itohuman(unsigned int perms)
81 char *msg = para_malloc(5 * sizeof(char));
83 msg[0] = perms & AFS_READ? 'a' : '-';
84 msg[1] = perms & AFS_WRITE? 'A' : '-';
85 msg[2] = perms & VSS_READ? 'v' : '-';
86 msg[3] = perms & VSS_WRITE? 'V' : '-';
94 static char *vss_get_status_flags(unsigned int flags)
96 char *msg = para_malloc(5 * sizeof(char));
98 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
99 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
100 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
101 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
106 static char *get_status(struct misc_meta_data *nmmd, int parser_friendly)
109 char *status, *flags; /* vss status info */
110 char *ut = uptime_str();
111 long offset = (nmmd->offset + 500) / 1000;
112 struct timeval current_time;
114 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
116 /* report real status */
117 status = vss_status_tohuman(nmmd->vss_status_flags);
118 flags = vss_get_status_flags(nmmd->vss_status_flags);
119 if (nmmd->size) { /* parent currently has an audio file open */
120 localtime_r(&nmmd->mtime, &mtime_tm);
121 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
123 gettimeofday(¤t_time, NULL);
124 WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
125 WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
126 WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
127 WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
128 WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
129 WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
130 WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
131 (long unsigned)nmmd->stream_start.tv_sec,
132 (long unsigned)nmmd->stream_start.tv_usec);
133 WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
134 (long unsigned)current_time.tv_sec,
135 (long unsigned)current_time.tv_usec);
142 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
145 /* this has to match sender.h */
146 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
148 scd->sender_num = -1;
150 return -E_COMMAND_SYNTAX;
151 for (i = 0; senders[i].name; i++)
152 if (!strcmp(senders[i].name, argv[1]))
154 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
155 if (!senders[i].name)
156 return -E_COMMAND_SYNTAX;
158 for (i = 0; subcmds[i]; i++)
159 if (!strcmp(subcmds[i], argv[2]))
162 return -E_COMMAND_SYNTAX;
164 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
165 return -E_SENDER_CMD;
166 switch (scd->cmd_num) {
170 return -E_COMMAND_SYNTAX;
174 if (argc != 4 || parse_cidr(argv[3], scd->host,
175 sizeof(scd->host), &scd->netmask) == NULL)
176 return -E_COMMAND_SYNTAX;
181 return -E_COMMAND_SYNTAX;
182 return parse_fec_url(argv[3], scd);
184 return -E_COMMAND_SYNTAX;
189 int com_sender(struct stream_cipher_context *scc, int argc, char * const * argv)
193 struct sender_command_data scd;
196 for (i = 0; senders[i].name; i++) {
197 char *tmp = make_message("%s%s\n",
198 msg? msg : "", senders[i].name);
202 ret = sc_send_buffer(scc, msg);
206 ret = check_sender_args(argc, argv, &scd);
208 if (scd.sender_num < 0)
210 msg = senders[scd.sender_num].help();
211 ret = sc_send_buffer(scc, msg);
216 switch (scd.cmd_num) {
219 assert(senders[scd.sender_num].resolve_target);
220 ret = senders[scd.sender_num].resolve_target(argv[3], &scd);
225 for (i = 0; i < 10; i++) {
226 mutex_lock(mmd_mutex);
227 if (mmd->sender_cmd_data.cmd_num >= 0) {
228 mutex_unlock(mmd_mutex);
232 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
233 mutex_unlock(mmd_mutex);
236 return (i < 10)? 1 : -E_LOCK;
240 int com_si(struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
244 char *sender_info = NULL;
247 return -E_COMMAND_SYNTAX;
248 mutex_lock(mmd_mutex);
249 for (i = 0; senders[i].name; i++) {
250 char *info = senders[i].info();
251 sender_info = para_strcat(sender_info, info);
255 ret = sc_send_va_buffer(scc, "version: " GIT_VERSION "\n"
256 "up: %s\nplayed: %u\n"
259 "connections (active/accepted/total): %u/%u/%u\n"
260 "current loglevel: %s\n"
261 "supported audio formats: %s\n"
266 mmd->active_connections,
270 SERVER_AUDIO_FORMATS,
273 mutex_unlock(mmd_mutex);
280 int com_version(struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
283 return -E_COMMAND_SYNTAX;
284 return sc_send_buffer(scc, VERSION_TEXT("server")
285 "built: " BUILD_DATE "\n"
286 UNAME_RS ", " CC_VERSION "\n"
290 #define EMPTY_STATUS_ITEMS \
295 ITEM(ATTRIBUTES_BITMAP) \
296 ITEM(ATTRIBUTES_TXT) \
307 ITEM(SECONDS_TOTAL) \
319 * Write a list of audio-file related status items with empty values.
321 * This is used by vss when currently no audio file is open.
323 static char *empty_status_items(int parser_friendly)
327 #define ITEM(x) "0004 %02x:\n"
330 #define ITEM(x) , SI_ ## x
335 #define ITEM(x) "%s:\n"
338 #define ITEM(x) ,status_item_list[SI_ ## x]
343 #undef EMPTY_STATUS_ITEMS
346 int com_stat(struct stream_cipher_context *scc, int argc, char * const * argv)
349 struct misc_meta_data tmp, *nmmd = &tmp;
352 int parser_friendly = 0;
354 para_sigaction(SIGUSR1, dummy);
356 for (i = 1; i < argc; i++) {
357 const char *arg = argv[i];
360 if (!strcmp(arg, "--")) {
364 if (!strncmp(arg, "-n=", 3)) {
365 ret = para_atoi32(arg + 3, &num);
370 if (!strcmp(arg, "-p")) {
374 return -E_COMMAND_SYNTAX;
377 return -E_COMMAND_SYNTAX;
380 s = get_status(nmmd, parser_friendly);
381 ret = sc_send_buffer(scc, s);
385 if (nmmd->vss_status_flags & VSS_NEXT) {
388 esi = empty_status_items(parser_friendly);
389 ret = sc_send_buffer(scc, esi);
393 send_afs_status(scc, parser_friendly);
395 if (num > 0 && !--num)
399 return -E_SERVER_CRASH;
405 static int send_list_of_commands(struct stream_cipher_context *scc, struct server_command *cmd,
410 for (i = 1; cmd->name; cmd++, i++) {
411 char *perms = cmd_perms_itohuman(cmd->perms);
412 ret = sc_send_va_buffer(scc, "%s\t%s\t%s\t%s\n", cmd->name,
423 /* returns string that must be freed by the caller */
424 static struct server_command *get_cmd_ptr(const char *name, char **handler)
426 struct server_command *cmd;
428 for (cmd = server_cmds; cmd->name; cmd++)
429 if (!strcmp(cmd->name, name)) {
431 *handler = para_strdup("server"); /* server commands */
434 /* not found, look for commands supported by afs */
435 for (cmd = afs_cmds; cmd->name; cmd++)
436 if (!strcmp(cmd->name, name)) {
438 *handler = para_strdup("afs");
445 int com_help(struct stream_cipher_context *scc, int argc, char * const * argv)
447 struct server_command *cmd;
448 char *perms, *handler;
452 /* no argument given, print list of commands */
453 if ((ret = send_list_of_commands(scc, server_cmds, "server")) < 0)
455 return send_list_of_commands(scc, afs_cmds, "afs");
457 /* argument given for help */
458 cmd = get_cmd_ptr(argv[1], &handler);
461 perms = cmd_perms_itohuman(cmd->perms);
462 ret = sc_send_va_buffer(scc,
481 int com_hup(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
484 return -E_COMMAND_SYNTAX;
485 kill(getppid(), SIGHUP);
490 int com_term(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
493 return -E_COMMAND_SYNTAX;
494 kill(getppid(), SIGTERM);
498 int com_play(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
501 return -E_COMMAND_SYNTAX;
502 mutex_lock(mmd_mutex);
503 mmd->new_vss_status_flags |= VSS_PLAYING;
504 mmd->new_vss_status_flags &= ~VSS_NOMORE;
505 mutex_unlock(mmd_mutex);
511 int com_stop(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
514 return -E_COMMAND_SYNTAX;
515 mutex_lock(mmd_mutex);
516 mmd->new_vss_status_flags &= ~VSS_PLAYING;
517 mmd->new_vss_status_flags &= ~VSS_REPOS;
518 mmd->new_vss_status_flags |= VSS_NEXT;
519 mutex_unlock(mmd_mutex);
524 int com_pause(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
527 return -E_COMMAND_SYNTAX;
528 mutex_lock(mmd_mutex);
529 if (!vss_paused() && !vss_stopped()) {
531 mmd->new_vss_status_flags &= ~VSS_PLAYING;
532 mmd->new_vss_status_flags &= ~VSS_NEXT;
534 mutex_unlock(mmd_mutex);
539 int com_next(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
542 return -E_COMMAND_SYNTAX;
543 mutex_lock(mmd_mutex);
545 mmd->new_vss_status_flags |= VSS_NEXT;
546 mutex_unlock(mmd_mutex);
551 int com_nomore(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
554 return -E_COMMAND_SYNTAX;
555 mutex_lock(mmd_mutex);
556 if (vss_playing() || vss_paused())
557 mmd->new_vss_status_flags |= VSS_NOMORE;
558 mutex_unlock(mmd_mutex);
563 int com_ff(__a_unused struct stream_cipher_context *scc, int argc, char * const * argv)
566 int ret, backwards = 0;
571 return -E_COMMAND_SYNTAX;
572 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
573 return -E_COMMAND_SYNTAX;
574 if (ret > 1 && c == '-')
575 backwards = 1; /* jmp backwards */
576 mutex_lock(mmd_mutex);
577 ret = -E_NO_AUDIO_FILE;
578 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
580 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
582 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
584 promille += 1000 * i / mmd->afd.afhi.seconds_total;
587 if (promille > 1000) {
588 mmd->new_vss_status_flags |= VSS_NEXT;
591 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
592 mmd->new_vss_status_flags |= VSS_REPOS;
593 mmd->new_vss_status_flags &= ~VSS_NEXT;
597 mutex_unlock(mmd_mutex);
602 int com_jmp(__a_unused struct stream_cipher_context *scc, int argc, char * const * argv)
608 return -E_COMMAND_SYNTAX;
609 if (sscanf(argv[1], "%lu", &i) <= 0)
610 return -E_COMMAND_SYNTAX;
611 mutex_lock(mmd_mutex);
612 ret = -E_NO_AUDIO_FILE;
613 if (!mmd->afd.afhi.chunks_total)
617 PARA_INFO_LOG("jumping to %lu%%\n", i);
618 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
619 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
620 mmd->chunks_sent, mmd->offset);
621 mmd->new_vss_status_flags |= VSS_REPOS;
622 mmd->new_vss_status_flags &= ~VSS_NEXT;
626 mutex_unlock(mmd_mutex);
631 * check if perms are sufficient to exec a command having perms cmd_perms.
632 * Returns 0 if perms are sufficient, -E_PERM otherwise.
634 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
636 PARA_DEBUG_LOG("checking permissions\n");
637 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
641 * Parse first string from *cmd and lookup in table of valid commands.
642 * On error, NULL is returned.
644 static struct server_command *parse_cmd(const char *cmdstr)
649 sscanf(cmdstr, "%200s%n", buf, &n);
653 return get_cmd_ptr(buf, NULL);
656 static int read_command(struct stream_cipher_context *scc, char **result)
660 char *command = NULL;
666 ret = sc_recv_buffer(scc, buf, sizeof(buf));
672 ret = -E_COMMAND_SYNTAX;
673 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
675 command = para_strcat(command, buf);
676 p = strstr(command, EOC_MSG);
682 ret = command? 1 : -E_COMMAND_SYNTAX;
692 static void reset_signals(void)
694 para_sigaction(SIGCHLD, SIG_IGN);
695 para_sigaction(SIGINT, SIG_DFL);
696 para_sigaction(SIGTERM, SIG_DFL);
697 para_sigaction(SIGHUP, SIG_DFL);
701 * Perform user authentication and execute a command.
703 * \param fd The file descriptor to send output to.
704 * \param peername Identifies the connecting peer.
706 * Whenever para_server accepts an incoming tcp connection on
707 * the port it listens on, it forks and the resulting child
708 * calls this function.
710 * An RSA-based challenge/response is used to authenticate
711 * the peer. It that authentication succeeds, a random
712 * session key is generated and sent back to the peer,
713 * encrypted with its RSA public key. From this point on,
714 * all transfers are crypted with this session key.
716 * Next it is checked if the peer supplied a valid server command or a command
717 * for the audio file selector. If yes, and if the user has sufficient
718 * permissions to execute that command, the function calls the corresponding
719 * command handler which does argument checking and further processing.
721 * In order to cope with a DOS attacks, a timeout is set up
722 * which terminates the function if the connection was not
723 * authenticated when the timeout expires.
725 * \sa alarm(2), crypt.c, crypt.h
727 __noreturn void handle_connect(int fd, const char *peername)
731 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
732 unsigned char challenge_hash[HASH_SIZE];
734 struct server_command *cmd = NULL;
736 char *p, *command = NULL;
738 struct stream_cipher_context scc = {.fd = fd};
741 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
742 ret = mark_fd_blocking(fd);
745 /* send Welcome message */
746 ret = send_va_buffer(fd, "This is para_server, version "
747 PACKAGE_VERSION ".\n" );
750 /* recv auth request line */
751 ret = recv_buffer(fd, buf, sizeof(buf));
755 ret = -E_AUTH_REQUEST;
759 ret = -E_AUTH_REQUEST;
760 if (strncmp(buf, AUTH_REQUEST_MSG, strlen(AUTH_REQUEST_MSG)))
762 p = buf + strlen(AUTH_REQUEST_MSG);
763 PARA_DEBUG_LOG("received auth request for user %s\n", p);
767 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
768 ret = pub_encrypt(u->pubkey, rand_buf, sizeof(rand_buf),
769 (unsigned char *)buf);
775 * We don't want to reveal our user names, so we send a
776 * challenge to the client even if the user does not exist, and
777 * fail the authentication later.
780 get_random_bytes_or_die((unsigned char *)buf, numbytes);
782 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
783 CHALLENGE_SIZE, numbytes);
784 ret = send_bin_buffer(fd, buf, numbytes);
787 /* recv challenge response */
788 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
792 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret);
797 * The correct response is the hash of the first CHALLENGE_SIZE bytes
798 * of the random data.
801 if (numbytes != HASH_SIZE)
803 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
804 if (memcmp(challenge_hash, buf, HASH_SIZE))
806 /* auth successful */
808 PARA_INFO_LOG("good auth for %s\n", u->name);
809 /* init stream cipher keys with the second part of the random buffer */
810 scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
811 scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN, SESSION_KEY_LEN);
812 ret = sc_send_buffer(&scc, PROCEED_MSG);
815 ret = read_command(&scc, &command);
816 if (ret == -E_COMMAND_SYNTAX)
821 cmd = parse_cmd(command);
824 /* valid command, check permissions */
825 ret = check_perms(u->perms, cmd);
828 /* valid command and sufficient perms */
829 ret = create_argv(command, "\n", &argv);
833 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
835 ret = cmd->handler(&scc, argc, argv);
837 mutex_lock(mmd_mutex);
839 mutex_unlock(mmd_mutex);
843 sc_send_va_buffer(&scc, "%s\n", para_strerror(-ret));
845 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
850 mutex_lock(mmd_mutex);
851 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
853 mmd->active_connections--;
854 mutex_unlock(mmd_mutex);
855 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);