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>
14 #include <openssl/rc4.h>
22 #include "server.cmdline.h"
35 #include "user_list.h"
36 #include "server_command_list.h"
37 #include "afs_command_list.h"
41 /** Commands including options must be shorter than this. */
42 #define MAX_COMMAND_LEN 32768
45 extern struct misc_meta_data *mmd;
46 extern struct sender senders[];
47 int send_afs_status(struct rc4_context *rc4c, int parser_friendly);
49 const char *status_item_list[] = {STATUS_ITEM_ARRAY};
51 static void dummy(__a_unused int s)
55 static void mmd_dup(struct misc_meta_data *new_mmd)
57 mutex_lock(mmd_mutex);
59 mutex_unlock(mmd_mutex);
63 * Compute human readable string containing vss status for given integer value.
65 * We don't want to use vss_playing() and friends here because we take a
66 * snapshot of the mmd struct and use the copy for computing the state of the
67 * vss. If the real data were used, we would take the mmd lock for a rather
68 * long time or risk to get an inconsistent view.
70 static char *vss_status_tohuman(unsigned int flags)
72 if (flags & VSS_PLAYING)
73 return para_strdup("playing");
75 return para_strdup("stopped");
76 return para_strdup("paused");
80 * return human readable permission string. Never returns NULL.
82 static char *cmd_perms_itohuman(unsigned int perms)
84 char *msg = para_malloc(5 * sizeof(char));
86 msg[0] = perms & AFS_READ? 'a' : '-';
87 msg[1] = perms & AFS_WRITE? 'A' : '-';
88 msg[2] = perms & VSS_READ? 'v' : '-';
89 msg[3] = perms & VSS_WRITE? 'V' : '-';
97 static char *vss_get_status_flags(unsigned int flags)
99 char *msg = para_malloc(5 * sizeof(char));
101 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
102 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
103 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
104 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
109 static char *get_status(struct misc_meta_data *nmmd, int parser_friendly)
112 char *status, *flags; /* vss status info */
113 char *ut = uptime_str();
114 long offset = (nmmd->offset + 500) / 1000;
115 struct timeval current_time;
117 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
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);
126 gettimeofday(¤t_time, NULL);
127 WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
128 WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
129 WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
130 WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
131 WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
132 WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
133 WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
134 (long unsigned)nmmd->stream_start.tv_sec,
135 (long unsigned)nmmd->stream_start.tv_usec);
136 WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
137 (long unsigned)current_time.tv_sec,
138 (long unsigned)current_time.tv_usec);
145 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
148 /* this has to match sender.h */
149 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
151 scd->sender_num = -1;
153 return -E_COMMAND_SYNTAX;
154 for (i = 0; senders[i].name; i++)
155 if (!strcmp(senders[i].name, argv[1]))
157 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
158 if (!senders[i].name)
159 return -E_COMMAND_SYNTAX;
161 for (i = 0; subcmds[i]; i++)
162 if (!strcmp(subcmds[i], argv[2]))
165 return -E_COMMAND_SYNTAX;
167 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
168 return -E_SENDER_CMD;
169 switch (scd->cmd_num) {
173 return -E_COMMAND_SYNTAX;
177 if (argc != 4 || parse_cidr(argv[3], scd->host,
178 sizeof(scd->host), &scd->netmask) == NULL)
179 return -E_COMMAND_SYNTAX;
184 return -E_COMMAND_SYNTAX;
185 return parse_fec_url(argv[3], scd);
187 return -E_COMMAND_SYNTAX;
192 int com_sender(struct rc4_context *rc4c, int argc, char * const * argv)
196 struct sender_command_data scd;
199 for (i = 0; senders[i].name; i++) {
200 char *tmp = make_message("%s%s\n",
201 msg? msg : "", senders[i].name);
205 ret = rc4_send_buffer(rc4c, msg);
209 ret = check_sender_args(argc, argv, &scd);
211 if (scd.sender_num < 0)
213 msg = senders[scd.sender_num].help();
214 ret = rc4_send_buffer(rc4c, msg);
219 switch (scd.cmd_num) {
222 assert(senders[scd.sender_num].resolve_target);
223 ret = senders[scd.sender_num].resolve_target(argv[3], &scd);
228 for (i = 0; i < 10; i++) {
229 mutex_lock(mmd_mutex);
230 if (mmd->sender_cmd_data.cmd_num >= 0) {
231 mutex_unlock(mmd_mutex);
235 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
236 mutex_unlock(mmd_mutex);
239 return (i < 10)? 1 : -E_LOCK;
243 int com_si(struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
247 char *sender_info = NULL;
250 return -E_COMMAND_SYNTAX;
251 mutex_lock(mmd_mutex);
252 for (i = 0; senders[i].name; i++) {
253 char *info = senders[i].info();
254 sender_info = para_strcat(sender_info, info);
258 ret = rc4_send_va_buffer(rc4c, "version: " GIT_VERSION "\n"
259 "up: %s\nplayed: %u\n"
262 "connections (active/accepted/total): %u/%u/%u\n"
263 "current loglevel: %s\n"
264 "supported audio formats: %s\n"
269 mmd->active_connections,
273 SERVER_AUDIO_FORMATS,
276 mutex_unlock(mmd_mutex);
283 int com_version(struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
286 return -E_COMMAND_SYNTAX;
287 return rc4_send_buffer(rc4c, VERSION_TEXT("server")
288 "built: " BUILD_DATE "\n"
289 UNAME_RS ", " CC_VERSION "\n"
293 #define EMPTY_STATUS_ITEMS \
298 ITEM(ATTRIBUTES_BITMAP) \
299 ITEM(ATTRIBUTES_TXT) \
310 ITEM(SECONDS_TOTAL) \
322 * Write a list of audio-file related status items with empty values.
324 * This is used by vss when currently no audio file is open.
326 static char *empty_status_items(int parser_friendly)
330 #define ITEM(x) "0004 %02x:\n"
333 #define ITEM(x) , SI_ ## x
338 #define ITEM(x) "%s:\n"
341 #define ITEM(x) ,status_item_list[SI_ ## x]
346 #undef EMPTY_STATUS_ITEMS
349 int com_stat(struct rc4_context *rc4c, int argc, char * const * argv)
352 struct misc_meta_data tmp, *nmmd = &tmp;
355 int parser_friendly = 0;
357 para_sigaction(SIGUSR1, dummy);
359 for (i = 1; i < argc; i++) {
360 const char *arg = argv[i];
363 if (!strcmp(arg, "--")) {
367 if (!strncmp(arg, "-n=", 3)) {
368 ret = para_atoi32(arg + 3, &num);
373 if (!strcmp(arg, "-p")) {
377 return -E_COMMAND_SYNTAX;
380 return -E_COMMAND_SYNTAX;
383 s = get_status(nmmd, parser_friendly);
384 ret = rc4_send_buffer(rc4c, s);
388 if (nmmd->vss_status_flags & VSS_NEXT) {
391 esi = empty_status_items(parser_friendly);
392 ret = rc4_send_buffer(rc4c, esi);
396 send_afs_status(rc4c, parser_friendly);
398 if (num > 0 && !--num)
402 return -E_SERVER_CRASH;
408 static int send_list_of_commands(struct rc4_context *rc4c, struct server_command *cmd,
413 for (i = 1; cmd->name; cmd++, i++) {
414 char *perms = cmd_perms_itohuman(cmd->perms);
415 ret = rc4_send_va_buffer(rc4c, "%s\t%s\t%s\t%s\n", cmd->name,
426 /* returns string that must be freed by the caller */
427 static struct server_command *get_cmd_ptr(const char *name, char **handler)
429 struct server_command *cmd;
431 for (cmd = server_cmds; cmd->name; cmd++)
432 if (!strcmp(cmd->name, name)) {
434 *handler = para_strdup("server"); /* server commands */
437 /* not found, look for commands supported by afs */
438 for (cmd = afs_cmds; cmd->name; cmd++)
439 if (!strcmp(cmd->name, name)) {
441 *handler = para_strdup("afs");
448 int com_help(struct rc4_context *rc4c, int argc, char * const * argv)
450 struct server_command *cmd;
451 char *perms, *handler;
455 /* no argument given, print list of commands */
456 if ((ret = send_list_of_commands(rc4c, server_cmds, "server")) < 0)
458 return send_list_of_commands(rc4c, afs_cmds, "afs");
460 /* argument given for help */
461 cmd = get_cmd_ptr(argv[1], &handler);
464 perms = cmd_perms_itohuman(cmd->perms);
465 ret = rc4_send_va_buffer(rc4c,
484 int com_hup(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
487 return -E_COMMAND_SYNTAX;
488 kill(getppid(), SIGHUP);
493 int com_term(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
496 return -E_COMMAND_SYNTAX;
497 kill(getppid(), SIGTERM);
501 int com_play(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
504 return -E_COMMAND_SYNTAX;
505 mutex_lock(mmd_mutex);
506 mmd->new_vss_status_flags |= VSS_PLAYING;
507 mmd->new_vss_status_flags &= ~VSS_NOMORE;
508 mutex_unlock(mmd_mutex);
514 int com_stop(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
517 return -E_COMMAND_SYNTAX;
518 mutex_lock(mmd_mutex);
519 mmd->new_vss_status_flags &= ~VSS_PLAYING;
520 mmd->new_vss_status_flags &= ~VSS_REPOS;
521 mmd->new_vss_status_flags |= VSS_NEXT;
522 mutex_unlock(mmd_mutex);
527 int com_pause(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
530 return -E_COMMAND_SYNTAX;
531 mutex_lock(mmd_mutex);
532 if (!vss_paused() && !vss_stopped()) {
534 mmd->new_vss_status_flags &= ~VSS_PLAYING;
535 mmd->new_vss_status_flags &= ~VSS_NEXT;
537 mutex_unlock(mmd_mutex);
542 int com_next(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
545 return -E_COMMAND_SYNTAX;
546 mutex_lock(mmd_mutex);
548 mmd->new_vss_status_flags |= VSS_NEXT;
549 mutex_unlock(mmd_mutex);
554 int com_nomore(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
557 return -E_COMMAND_SYNTAX;
558 mutex_lock(mmd_mutex);
559 if (vss_playing() || vss_paused())
560 mmd->new_vss_status_flags |= VSS_NOMORE;
561 mutex_unlock(mmd_mutex);
566 int com_ff(__a_unused struct rc4_context *rc4c, int argc, char * const * argv)
569 int ret, backwards = 0;
574 return -E_COMMAND_SYNTAX;
575 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
576 return -E_COMMAND_SYNTAX;
577 if (ret > 1 && c == '-')
578 backwards = 1; /* jmp backwards */
579 mutex_lock(mmd_mutex);
580 ret = -E_NO_AUDIO_FILE;
581 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
583 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
585 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
587 promille += 1000 * i / mmd->afd.afhi.seconds_total;
590 if (promille > 1000) {
591 mmd->new_vss_status_flags |= VSS_NEXT;
594 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
595 mmd->new_vss_status_flags |= VSS_REPOS;
596 mmd->new_vss_status_flags &= ~VSS_NEXT;
600 mutex_unlock(mmd_mutex);
605 int com_jmp(__a_unused struct rc4_context *rc4c, int argc, char * const * argv)
611 return -E_COMMAND_SYNTAX;
612 if (sscanf(argv[1], "%lu", &i) <= 0)
613 return -E_COMMAND_SYNTAX;
614 mutex_lock(mmd_mutex);
615 ret = -E_NO_AUDIO_FILE;
616 if (!mmd->afd.afhi.chunks_total)
620 PARA_INFO_LOG("jumping to %lu%%\n", i);
621 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
622 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
623 mmd->chunks_sent, mmd->offset);
624 mmd->new_vss_status_flags |= VSS_REPOS;
625 mmd->new_vss_status_flags &= ~VSS_NEXT;
629 mutex_unlock(mmd_mutex);
634 * check if perms are sufficient to exec a command having perms cmd_perms.
635 * Returns 0 if perms are sufficient, -E_PERM otherwise.
637 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
639 PARA_DEBUG_LOG("checking permissions\n");
640 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
644 * Parse first string from *cmd and lookup in table of valid commands.
645 * On error, NULL is returned.
647 static struct server_command *parse_cmd(const char *cmdstr)
652 sscanf(cmdstr, "%200s%n", buf, &n);
656 return get_cmd_ptr(buf, NULL);
659 static int read_command(struct rc4_context *rc4c, char **result)
663 char *command = NULL;
669 ret = rc4_recv_buffer(rc4c, buf, sizeof(buf));
675 ret = -E_COMMAND_SYNTAX;
676 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
678 command = para_strcat(command, buf);
679 p = strstr(command, EOC_MSG);
685 ret = command? 1 : -E_COMMAND_SYNTAX;
695 static void reset_signals(void)
697 para_sigaction(SIGCHLD, SIG_IGN);
698 para_sigaction(SIGINT, SIG_DFL);
699 para_sigaction(SIGTERM, SIG_DFL);
700 para_sigaction(SIGHUP, SIG_DFL);
704 * Perform user authentication and execute a command.
706 * \param fd The file descriptor to send output to.
707 * \param peername Identifies the connecting peer.
709 * Whenever para_server accepts an incoming tcp connection on
710 * the port it listens on, it forks and the resulting child
711 * calls this function.
713 * An RSA-based challenge/response is used to authenticate
714 * the peer. It that authentication succeeds, a random RC4
715 * session key is generated and sent back to the peer,
716 * encrypted with its RSA public key. From this point on,
717 * all transfers are crypted with this session key.
719 * Next it is checked if the peer supplied a valid server command or a command
720 * for the audio file selector. If yes, and if the user has sufficient
721 * permissions to execute that command, the function calls the corresponding
722 * command handler which does argument checking and further processing.
724 * In order to cope with a DOS attacks, a timeout is set up
725 * which terminates the function if the connection was not
726 * authenticated when the timeout expires.
728 * \sa alarm(2), rc4(3), crypt.c, crypt.h
730 __noreturn void handle_connect(int fd, const char *peername)
734 unsigned char rand_buf[CHALLENGE_SIZE + 2 * RC4_KEY_LEN];
735 unsigned char challenge_sha1[HASH_SIZE];
737 struct server_command *cmd = NULL;
739 char *p, *command = NULL;
741 struct rc4_context rc4c = {.fd = fd};
744 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
745 ret = mark_fd_blocking(fd);
748 /* send Welcome message */
749 ret = send_va_buffer(fd, "This is para_server, version "
750 PACKAGE_VERSION ".\n" );
753 /* recv auth request line */
754 ret = recv_buffer(fd, buf, sizeof(buf));
758 ret = -E_AUTH_REQUEST;
762 ret = -E_AUTH_REQUEST;
763 if (strncmp(buf, AUTH_REQUEST_MSG, strlen(AUTH_REQUEST_MSG)))
765 p = buf + strlen(AUTH_REQUEST_MSG);
766 PARA_DEBUG_LOG("received auth request for user %s\n", p);
770 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
771 ret = para_encrypt_buffer(u->rsa, rand_buf, sizeof(rand_buf),
772 (unsigned char *)buf);
778 * We don't want to reveal our user names, so we send a
779 * challenge to the client even if the user does not exist, and
780 * fail the authentication later.
783 get_random_bytes_or_die((unsigned char *)buf, numbytes);
785 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
786 CHALLENGE_SIZE, numbytes);
787 ret = send_bin_buffer(fd, buf, numbytes);
790 /* recv challenge response */
791 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
795 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret);
800 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
801 * of the random data.
804 if (numbytes != HASH_SIZE)
806 sha1_hash((char *)rand_buf, CHALLENGE_SIZE, challenge_sha1);
807 if (memcmp(challenge_sha1, buf, HASH_SIZE))
809 /* auth successful */
811 PARA_INFO_LOG("good auth for %s\n", u->name);
812 /* init rc4 keys with the second part of the random buffer */
813 RC4_set_key(&rc4c.recv_key, RC4_KEY_LEN, rand_buf + CHALLENGE_SIZE);
814 RC4_set_key(&rc4c.send_key, RC4_KEY_LEN, rand_buf + CHALLENGE_SIZE
816 ret = rc4_send_buffer(&rc4c, PROCEED_MSG);
819 ret = read_command(&rc4c, &command);
820 if (ret == -E_COMMAND_SYNTAX)
825 cmd = parse_cmd(command);
828 /* valid command, check permissions */
829 ret = check_perms(u->perms, cmd);
832 /* valid command and sufficient perms */
833 ret = create_argv(command, "\n", &argv);
837 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
839 ret = cmd->handler(&rc4c, argc, argv);
841 mutex_lock(mmd_mutex);
843 mutex_unlock(mmd_mutex);
847 rc4_send_va_buffer(&rc4c, "%s\n", para_strerror(-ret));
849 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
852 mutex_lock(mmd_mutex);
853 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
855 mmd->active_connections--;
856 mutex_unlock(mmd_mutex);
857 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);