2 * Copyright (C) 1997-2012 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>
19 #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 command_context *cc, int parser_friendly);
46 static void dummy(__a_unused int s)
50 static void mmd_dup(struct misc_meta_data *new_mmd)
52 mutex_lock(mmd_mutex);
54 mutex_unlock(mmd_mutex);
58 * Compute human readable string containing vss status for given integer value.
60 * We don't want to use vss_playing() and friends here because we take a
61 * snapshot of the mmd struct and use the copy for computing the state of the
62 * vss. If the real data were used, we would take the mmd lock for a rather
63 * long time or risk to get an inconsistent view.
65 static char *vss_status_tohuman(unsigned int flags)
67 if (flags & VSS_PLAYING)
68 return para_strdup("playing");
70 return para_strdup("stopped");
71 return para_strdup("paused");
75 * return human readable permission string. Never returns NULL.
77 static char *cmd_perms_itohuman(unsigned int perms)
79 char *msg = para_malloc(5 * sizeof(char));
81 msg[0] = perms & AFS_READ? 'a' : '-';
82 msg[1] = perms & AFS_WRITE? 'A' : '-';
83 msg[2] = perms & VSS_READ? 'v' : '-';
84 msg[3] = perms & VSS_WRITE? 'V' : '-';
92 static char *vss_get_status_flags(unsigned int flags)
94 char *msg = para_malloc(5 * sizeof(char));
96 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
97 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
98 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
99 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
104 static char *get_status(struct misc_meta_data *nmmd, int parser_friendly)
107 char *status, *flags; /* vss status info */
108 /* nobody updates our version of "now" */
109 char *ut = get_server_uptime_str(NULL);
110 long offset = (nmmd->offset + 500) / 1000;
111 struct timeval current_time;
113 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
115 /* report real status */
116 status = vss_status_tohuman(nmmd->vss_status_flags);
117 flags = vss_get_status_flags(nmmd->vss_status_flags);
118 if (nmmd->size) { /* parent currently has an audio file open */
119 localtime_r(&nmmd->mtime, &mtime_tm);
120 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
122 gettimeofday(¤t_time, NULL);
124 * The calls to WRITE_STATUS_ITEM() below never fail because
125 * b->max_size is zero (unlimited), see para_printf(). However, clang
126 * is not smart enough to prove this and complains nevertheless.
127 * Casting the return value to void silences clang.
129 (void)WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
130 (void)WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
131 (void)WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
132 (void)WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
133 (void)WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
134 (void)WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
135 (void)WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
136 (long unsigned)nmmd->stream_start.tv_sec,
137 (long unsigned)nmmd->stream_start.tv_usec);
138 (void)WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
139 (long unsigned)current_time.tv_sec,
140 (long unsigned)current_time.tv_usec);
147 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
150 /* this has to match sender.h */
151 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
153 scd->sender_num = -1;
155 return -E_COMMAND_SYNTAX;
156 for (i = 0; senders[i].name; i++)
157 if (!strcmp(senders[i].name, argv[1]))
159 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
160 if (!senders[i].name)
161 return -E_COMMAND_SYNTAX;
163 for (i = 0; subcmds[i]; i++)
164 if (!strcmp(subcmds[i], argv[2]))
167 return -E_COMMAND_SYNTAX;
169 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
170 return -E_SENDER_CMD;
171 switch (scd->cmd_num) {
175 return -E_COMMAND_SYNTAX;
179 if (argc != 4 || parse_cidr(argv[3], scd->host,
180 sizeof(scd->host), &scd->netmask) == NULL)
181 return -E_COMMAND_SYNTAX;
186 return -E_COMMAND_SYNTAX;
187 return parse_fec_url(argv[3], scd);
189 return -E_COMMAND_SYNTAX;
194 int com_sender(struct command_context *cc)
198 struct sender_command_data scd;
201 for (i = 0; senders[i].name; i++) {
202 char *tmp = make_message("%s%s\n",
203 msg? msg : "", senders[i].name);
207 ret = sc_send_buffer(&cc->scc, msg);
211 ret = check_sender_args(cc->argc, cc->argv, &scd);
213 if (scd.sender_num < 0)
215 msg = senders[scd.sender_num].help();
216 ret = sc_send_buffer(&cc->scc, msg);
221 switch (scd.cmd_num) {
224 assert(senders[scd.sender_num].resolve_target);
225 ret = senders[scd.sender_num].resolve_target(cc->argv[3], &scd);
230 for (i = 0; i < 10; i++) {
231 mutex_lock(mmd_mutex);
232 if (mmd->sender_cmd_data.cmd_num >= 0) {
233 mutex_unlock(mmd_mutex);
237 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
238 mutex_unlock(mmd_mutex);
241 return (i < 10)? 1 : -E_LOCK;
245 int com_si(struct command_context *cc)
249 char *sender_info = NULL;
252 return -E_COMMAND_SYNTAX;
253 mutex_lock(mmd_mutex);
254 for (i = 0; senders[i].name; i++) {
255 char *info = senders[i].info();
256 sender_info = para_strcat(sender_info, info);
259 ut = get_server_uptime_str(now);
260 ret = sc_send_va_buffer(&cc->scc, "version: " GIT_VERSION "\n"
261 "up: %s\nplayed: %u\n"
264 "connections (active/accepted/total): %u/%u/%u\n"
265 "current loglevel: %s\n"
266 "supported audio formats: %s\n"
271 mmd->active_connections,
275 SERVER_AUDIO_FORMATS,
278 mutex_unlock(mmd_mutex);
285 int com_version(struct command_context *cc)
288 return -E_COMMAND_SYNTAX;
289 return sc_send_buffer(&cc->scc, VERSION_TEXT("server")
290 "built: " BUILD_DATE "\n"
291 UNAME_RS ", " CC_VERSION "\n"
295 #define EMPTY_STATUS_ITEMS \
300 ITEM(ATTRIBUTES_BITMAP) \
301 ITEM(ATTRIBUTES_TXT) \
312 ITEM(SECONDS_TOTAL) \
324 * Write a list of audio-file related status items with empty values.
326 * This is used by vss when currently no audio file is open.
328 static char *empty_status_items(int parser_friendly)
332 #define ITEM(x) "0004 %02x:\n"
335 #define ITEM(x) , SI_ ## x
340 #define ITEM(x) "%s:\n"
343 #define ITEM(x) ,status_item_list[SI_ ## x]
348 #undef EMPTY_STATUS_ITEMS
351 int com_stat(struct command_context *cc)
354 struct misc_meta_data tmp, *nmmd = &tmp;
357 int parser_friendly = 0;
359 para_sigaction(SIGUSR1, dummy);
361 for (i = 1; i < cc->argc; i++) {
362 const char *arg = cc->argv[i];
365 if (!strcmp(arg, "--")) {
369 if (!strncmp(arg, "-n=", 3)) {
370 ret = para_atoi32(arg + 3, &num);
375 if (!strcmp(arg, "-p")) {
379 return -E_COMMAND_SYNTAX;
382 return -E_COMMAND_SYNTAX;
385 s = get_status(nmmd, parser_friendly);
386 ret = sc_send_buffer(&cc->scc, s);
390 if (nmmd->vss_status_flags & VSS_NEXT) {
393 esi = empty_status_items(parser_friendly);
394 ret = sc_send_buffer(&cc->scc, esi);
398 send_afs_status(cc, parser_friendly);
400 if (num > 0 && !--num)
404 return -E_SERVER_CRASH;
410 static int send_list_of_commands(struct stream_cipher_context *scc, struct server_command *cmd,
415 for (i = 1; cmd->name; cmd++, i++) {
416 char *perms = cmd_perms_itohuman(cmd->perms);
417 ret = sc_send_va_buffer(scc, "%s\t%s\t%s\t%s\n", cmd->name,
428 /* returns string that must be freed by the caller */
429 static struct server_command *get_cmd_ptr(const char *name, char **handler)
431 struct server_command *cmd;
433 for (cmd = server_cmds; cmd->name; cmd++)
434 if (!strcmp(cmd->name, name)) {
436 *handler = para_strdup("server"); /* server commands */
439 /* not found, look for commands supported by afs */
440 for (cmd = afs_cmds; cmd->name; cmd++)
441 if (!strcmp(cmd->name, name)) {
443 *handler = para_strdup("afs");
450 int com_help(struct command_context *cc)
452 struct server_command *cmd;
453 char *perms, *handler;
457 /* no argument given, print list of commands */
458 if ((ret = send_list_of_commands(&cc->scc, server_cmds, "server")) < 0)
460 return send_list_of_commands(&cc->scc, afs_cmds, "afs");
462 /* argument given for help */
463 cmd = get_cmd_ptr(cc->argv[1], &handler);
466 perms = cmd_perms_itohuman(cmd->perms);
467 ret = sc_send_va_buffer(&cc->scc,
486 int com_hup(struct command_context *cc)
489 return -E_COMMAND_SYNTAX;
490 kill(getppid(), SIGHUP);
495 int com_term(struct command_context *cc)
498 return -E_COMMAND_SYNTAX;
499 kill(getppid(), SIGTERM);
503 int com_play(struct command_context *cc)
506 return -E_COMMAND_SYNTAX;
507 mutex_lock(mmd_mutex);
508 mmd->new_vss_status_flags |= VSS_PLAYING;
509 mmd->new_vss_status_flags &= ~VSS_NOMORE;
510 mutex_unlock(mmd_mutex);
515 int com_stop(struct command_context *cc)
518 return -E_COMMAND_SYNTAX;
519 mutex_lock(mmd_mutex);
520 mmd->new_vss_status_flags &= ~VSS_PLAYING;
521 mmd->new_vss_status_flags &= ~VSS_REPOS;
522 mmd->new_vss_status_flags |= VSS_NEXT;
523 mutex_unlock(mmd_mutex);
528 int com_pause(struct command_context *cc)
531 return -E_COMMAND_SYNTAX;
532 mutex_lock(mmd_mutex);
533 if (!vss_paused() && !vss_stopped()) {
535 mmd->new_vss_status_flags &= ~VSS_PLAYING;
536 mmd->new_vss_status_flags &= ~VSS_NEXT;
538 mutex_unlock(mmd_mutex);
543 int com_next(struct command_context *cc)
546 return -E_COMMAND_SYNTAX;
547 mutex_lock(mmd_mutex);
549 mmd->new_vss_status_flags |= VSS_NEXT;
550 mutex_unlock(mmd_mutex);
555 int com_nomore(struct command_context *cc)
558 return -E_COMMAND_SYNTAX;
559 mutex_lock(mmd_mutex);
560 if (vss_playing() || vss_paused())
561 mmd->new_vss_status_flags |= VSS_NOMORE;
562 mutex_unlock(mmd_mutex);
567 int com_ff(struct command_context *cc)
570 int ret, backwards = 0;
575 return -E_COMMAND_SYNTAX;
576 if (!(ret = sscanf(cc->argv[1], "%u%c", &i, &c)))
577 return -E_COMMAND_SYNTAX;
578 if (ret > 1 && c == '-')
579 backwards = 1; /* jmp backwards */
580 mutex_lock(mmd_mutex);
581 ret = -E_NO_AUDIO_FILE;
582 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
584 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
586 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
588 promille += 1000 * i / mmd->afd.afhi.seconds_total;
591 if (promille > 1000) {
592 mmd->new_vss_status_flags |= VSS_NEXT;
595 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
596 mmd->new_vss_status_flags |= VSS_REPOS;
597 mmd->new_vss_status_flags &= ~VSS_NEXT;
601 mutex_unlock(mmd_mutex);
606 int com_jmp(struct command_context *cc)
612 return -E_COMMAND_SYNTAX;
613 if (sscanf(cc->argv[1], "%lu", &i) <= 0)
614 return -E_COMMAND_SYNTAX;
615 mutex_lock(mmd_mutex);
616 ret = -E_NO_AUDIO_FILE;
617 if (!mmd->afd.afhi.chunks_total)
621 PARA_INFO_LOG("jumping to %lu%%\n", i);
622 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
623 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
624 mmd->chunks_sent, mmd->offset);
625 mmd->new_vss_status_flags |= VSS_REPOS;
626 mmd->new_vss_status_flags &= ~VSS_NEXT;
630 mutex_unlock(mmd_mutex);
635 * check if perms are sufficient to exec a command having perms cmd_perms.
636 * Returns 0 if perms are sufficient, -E_PERM otherwise.
638 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
640 PARA_DEBUG_LOG("checking permissions\n");
641 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
645 * Parse first string from *cmd and lookup in table of valid commands.
646 * On error, NULL is returned.
648 static struct server_command *parse_cmd(const char *cmdstr)
653 sscanf(cmdstr, "%200s%n", buf, &n);
657 return get_cmd_ptr(buf, NULL);
660 static int read_command(struct stream_cipher_context *scc, char **result)
664 char *command = NULL;
670 ret = sc_recv_buffer(scc, buf, sizeof(buf));
676 ret = -E_COMMAND_SYNTAX;
677 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
679 command = para_strcat(command, buf);
680 p = strstr(command, EOC_MSG);
686 ret = command? 1 : -E_COMMAND_SYNTAX;
696 static void reset_signals(void)
698 para_sigaction(SIGCHLD, SIG_IGN);
699 para_sigaction(SIGINT, SIG_DFL);
700 para_sigaction(SIGTERM, SIG_DFL);
701 para_sigaction(SIGHUP, SIG_DFL);
704 static int parse_auth_request(char *buf, int len, struct user **u,
708 char *p, *username, **features = NULL;
709 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
712 *use_sideband = false;
713 if (len < auth_rq_len + 2)
714 return -E_AUTH_REQUEST;
715 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
716 return -E_AUTH_REQUEST;
717 username = buf + auth_rq_len;
718 p = strchr(username, ' ');
722 return -E_AUTH_REQUEST;
725 create_argv(p, ",", &features);
726 for (i = 0; features[i]; i++) {
727 if (strcmp(features[i], "sideband") == 0)
728 *use_sideband = true;
730 ret = -E_BAD_FEATURE;
735 PARA_DEBUG_LOG("received auth request for user %s (sideband = %s)\n",
736 username, *use_sideband? "true" : "false");
737 *u = lookup_user(username);
745 * Perform user authentication and execute a command.
747 * \param fd The file descriptor to send output to.
748 * \param peername Identifies the connecting peer.
750 * Whenever para_server accepts an incoming tcp connection on
751 * the port it listens on, it forks and the resulting child
752 * calls this function.
754 * An RSA-based challenge/response is used to authenticate
755 * the peer. It that authentication succeeds, a random
756 * session key is generated and sent back to the peer,
757 * encrypted with its RSA public key. From this point on,
758 * all transfers are crypted with this session key.
760 * Next it is checked if the peer supplied a valid server command or a command
761 * for the audio file selector. If yes, and if the user has sufficient
762 * permissions to execute that command, the function calls the corresponding
763 * command handler which does argument checking and further processing.
765 * In order to cope with a DOS attacks, a timeout is set up
766 * which terminates the function if the connection was not
767 * authenticated when the timeout expires.
769 * \sa alarm(2), crypt.c, crypt.h
771 __noreturn void handle_connect(int fd, const char *peername)
775 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
776 unsigned char challenge_hash[HASH_SIZE];
777 char *p, *command = NULL;
779 struct command_context cc_struct = {.peer = peername}, *cc = &cc_struct;
783 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
784 ret = mark_fd_blocking(fd);
787 /* send Welcome message */
788 ret = write_va_buffer(fd, "This is para_server, version "
789 PACKAGE_VERSION ".\n"
790 "Features: sideband,foo\n"
794 /* recv auth request line */
795 ret = recv_buffer(fd, buf, sizeof(buf));
798 ret = parse_auth_request(buf, ret, &cc->u, &cc->use_sideband);
801 p = buf + strlen(AUTH_REQUEST_MSG);
802 PARA_DEBUG_LOG("received auth request for user %s\n", p);
803 cc->u = lookup_user(p);
805 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
806 ret = pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
807 (unsigned char *)buf);
813 * We don't want to reveal our user names, so we send a
814 * challenge to the client even if the user does not exist, and
815 * fail the authentication later.
818 get_random_bytes_or_die((unsigned char *)buf, numbytes);
820 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
821 CHALLENGE_SIZE, numbytes);
822 ret = write_all(fd, buf, numbytes);
825 /* recv challenge response */
826 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
830 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret);
835 * The correct response is the hash of the first CHALLENGE_SIZE bytes
836 * of the random data.
839 if (numbytes != HASH_SIZE)
841 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
842 if (memcmp(challenge_hash, buf, HASH_SIZE))
844 /* auth successful */
846 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
847 /* init stream cipher keys with the second part of the random buffer */
848 cc->scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
849 cc->scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN, SESSION_KEY_LEN);
850 ret = sc_send_buffer(&cc->scc, PROCEED_MSG);
853 ret = read_command(&cc->scc, &command);
854 if (ret == -E_COMMAND_SYNTAX)
859 cc->cmd = parse_cmd(command);
862 /* valid command, check permissions */
863 ret = check_perms(cc->u->perms, cc->cmd);
866 /* valid command and sufficient perms */
867 ret = create_argv(command, "\n", &cc->argv);
871 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cc->cmd->name,
872 cc->u->name, peername);
873 ret = cc->cmd->handler(cc);
875 mutex_lock(mmd_mutex);
877 mutex_unlock(mmd_mutex);
881 sc_send_va_buffer(&cc->scc, "%s\n", para_strerror(-ret));
883 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
886 sc_free(cc->scc.recv);
887 sc_free(cc->scc.send);
888 mutex_lock(mmd_mutex);
889 if (cc->cmd && (cc->cmd->perms & AFS_WRITE) && ret >= 0)
891 mmd->active_connections--;
892 mutex_unlock(mmd_mutex);
893 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);