2 * Copyright (C) 1997-2009 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>
20 #include "server.cmdline.h"
33 #include "user_list.h"
34 #include "server_command_list.h"
35 #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 rc4_context *rc4c, 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 char *ut = uptime_str();
112 long offset = (nmmd->offset + 500) / 1000;
113 struct timeval current_time;
115 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
117 /* report real status */
118 status = vss_status_tohuman(nmmd->vss_status_flags);
119 flags = vss_get_status_flags(nmmd->vss_status_flags);
120 if (nmmd->size) { /* parent currently has an audio file open */
121 localtime_r(&nmmd->mtime, &mtime_tm);
122 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
124 gettimeofday(¤t_time, NULL);
125 WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
126 WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
127 WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
128 WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
129 WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
130 WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
131 WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
132 (long unsigned)nmmd->stream_start.tv_sec,
133 (long unsigned)nmmd->stream_start.tv_usec);
134 WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
135 (long unsigned)current_time.tv_sec,
136 (long unsigned)current_time.tv_usec);
143 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
146 /* this has to match sender.h */
147 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
149 scd->sender_num = -1;
151 return -E_COMMAND_SYNTAX;
152 for (i = 0; senders[i].name; i++)
153 if (!strcmp(senders[i].name, argv[1]))
155 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
156 if (!senders[i].name)
157 return -E_COMMAND_SYNTAX;
159 for (i = 0; subcmds[i]; i++)
160 if (!strcmp(subcmds[i], argv[2]))
163 return -E_COMMAND_SYNTAX;
165 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
166 return -E_SENDER_CMD;
167 switch (scd->cmd_num) {
171 return -E_COMMAND_SYNTAX;
175 if (argc != 4 || parse_cidr(argv[3], scd->host,
176 sizeof(scd->host), &scd->netmask) == NULL)
177 return -E_COMMAND_SYNTAX;
182 return -E_COMMAND_SYNTAX;
183 return parse_fec_url(argv[3], scd);
185 return -E_COMMAND_SYNTAX;
190 int com_sender(struct rc4_context *rc4c, int argc, char * const * argv)
193 struct sender_command_data scd;
197 for (i = 0; senders[i].name; i++) {
198 char *tmp = make_message("%s%s\n",
199 msg? msg : "", senders[i].name);
203 ret = rc4_send_buffer(rc4c, msg);
207 ret = check_sender_args(argc, argv, &scd);
210 if (scd.sender_num < 0)
212 msg = senders[scd.sender_num].help();
213 ret = rc4_send_buffer(rc4c, msg);
217 for (i = 0; i < 10; i++) {
218 mutex_lock(mmd_mutex);
219 if (mmd->sender_cmd_data.cmd_num >= 0) {
220 mutex_unlock(mmd_mutex);
224 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
225 mutex_unlock(mmd_mutex);
228 return (i < 10)? 1 : -E_LOCK;
232 int com_si(struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
236 char *sender_info = NULL, *sender_list = NULL;
239 return -E_COMMAND_SYNTAX;
240 mutex_lock(mmd_mutex);
241 for (i = 0; senders[i].name; i++) {
242 char *info = senders[i].info();
243 sender_info = para_strcat(sender_info, info);
245 sender_list = para_strcat(sender_list, senders[i].name);
246 sender_list = para_strcat(sender_list, " ");
249 ret = rc4_send_va_buffer(rc4c, "up: %s\nplayed: %u\n"
252 "connections (active/accepted/total): %u/%u/%u\n"
253 "current loglevel: %s\n"
254 "supported audio formats: %s\n"
255 "supported senders: %s\n"
260 mmd->active_connections,
264 supported_audio_formats(),
268 mutex_unlock(mmd_mutex);
276 int com_version(struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
279 return -E_COMMAND_SYNTAX;
280 return rc4_send_buffer(rc4c, VERSION_TEXT("server")
281 "built: " BUILD_DATE "\n"
282 UNAME_RS ", " CC_VERSION "\n"
286 #define EMPTY_STATUS_ITEMS \
291 ITEM(ATTRIBUTES_BITMAP) \
292 ITEM(ATTRIBUTES_TXT) \
303 ITEM(SECONDS_TOTAL) \
315 * Write a list of audio-file related status items with empty values.
317 * This is used by vss when currently no audio file is open.
319 static char *empty_status_items(int parser_friendly)
323 #define ITEM(x) "0004 %02x:\n"
326 #define ITEM(x) , SI_ ## x
331 #define ITEM(x) "%s:\n"
334 #define ITEM(x) ,status_item_list[SI_ ## x]
339 #undef EMPTY_STATUS_ITEMS
342 int com_stat(struct rc4_context *rc4c, int argc, char * const * argv)
345 struct misc_meta_data tmp, *nmmd = &tmp;
348 int parser_friendly = 0;
350 para_sigaction(SIGUSR1, dummy);
352 for (i = 1; i < argc; i++) {
353 const char *arg = argv[i];
356 if (!strcmp(arg, "--")) {
360 if (!strncmp(arg, "-n=", 3)) {
361 ret = para_atoi32(arg + 3, &num);
366 if (!strcmp(arg, "-p")) {
370 return -E_COMMAND_SYNTAX;
373 return -E_COMMAND_SYNTAX;
376 s = get_status(nmmd, parser_friendly);
377 ret = rc4_send_buffer(rc4c, s);
381 if (nmmd->vss_status_flags & VSS_NEXT) {
384 esi = empty_status_items(parser_friendly);
385 ret = rc4_send_buffer(rc4c, esi);
389 send_afs_status(rc4c, parser_friendly);
391 if (num > 0 && !--num)
395 return -E_SERVER_CRASH;
401 static int send_list_of_commands(struct rc4_context *rc4c, struct server_command *cmd,
406 for (i = 1; cmd->name; cmd++, i++) {
407 char *perms = cmd_perms_itohuman(cmd->perms);
408 ret = rc4_send_va_buffer(rc4c, "%s\t%s\t%s\t%s\n", cmd->name,
419 /* returns string that must be freed by the caller */
420 static struct server_command *get_cmd_ptr(const char *name, char **handler)
422 struct server_command *cmd;
424 for (cmd = server_cmds; cmd->name; cmd++)
425 if (!strcmp(cmd->name, name)) {
427 *handler = para_strdup("server"); /* server commands */
430 /* not found, look for commands supported by afs */
431 for (cmd = afs_cmds; cmd->name; cmd++)
432 if (!strcmp(cmd->name, name)) {
434 *handler = para_strdup("afs");
441 int com_help(struct rc4_context *rc4c, int argc, char * const * argv)
443 struct server_command *cmd;
444 char *perms, *handler;
448 /* no argument given, print list of commands */
449 if ((ret = send_list_of_commands(rc4c, server_cmds, "server")) < 0)
451 return send_list_of_commands(rc4c, afs_cmds, "afs");
453 /* argument given for help */
454 cmd = get_cmd_ptr(argv[1], &handler);
459 perms = cmd_perms_itohuman(cmd->perms);
460 ret = rc4_send_va_buffer(rc4c,
479 int com_hup(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
482 return -E_COMMAND_SYNTAX;
483 kill(getppid(), SIGHUP);
488 int com_term(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
491 return -E_COMMAND_SYNTAX;
492 kill(getppid(), SIGTERM);
496 int com_play(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
499 return -E_COMMAND_SYNTAX;
500 mutex_lock(mmd_mutex);
501 mmd->new_vss_status_flags |= VSS_PLAYING;
502 mmd->new_vss_status_flags &= ~VSS_NOMORE;
503 mutex_unlock(mmd_mutex);
509 int com_stop(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
512 return -E_COMMAND_SYNTAX;
513 mutex_lock(mmd_mutex);
514 mmd->new_vss_status_flags &= ~VSS_PLAYING;
515 mmd->new_vss_status_flags &= ~VSS_REPOS;
516 mmd->new_vss_status_flags |= VSS_NEXT;
517 mutex_unlock(mmd_mutex);
522 int com_pause(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
525 return -E_COMMAND_SYNTAX;
526 mutex_lock(mmd_mutex);
527 if (!vss_paused() && !vss_stopped()) {
529 mmd->new_vss_status_flags &= ~VSS_PLAYING;
530 mmd->new_vss_status_flags &= ~VSS_NEXT;
532 mutex_unlock(mmd_mutex);
537 int com_next(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
540 return -E_COMMAND_SYNTAX;
541 mutex_lock(mmd_mutex);
543 mmd->new_vss_status_flags |= VSS_NEXT;
544 mutex_unlock(mmd_mutex);
549 int com_nomore(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
552 return -E_COMMAND_SYNTAX;
553 mutex_lock(mmd_mutex);
554 if (vss_playing() || vss_paused())
555 mmd->new_vss_status_flags |= VSS_NOMORE;
556 mutex_unlock(mmd_mutex);
561 int com_ff(__a_unused struct rc4_context *rc4c, int argc, char * const * argv)
564 int ret, backwards = 0;
569 return -E_COMMAND_SYNTAX;
570 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
571 return -E_COMMAND_SYNTAX;
572 if (ret > 1 && c == '-')
573 backwards = 1; /* jmp backwards */
574 mutex_lock(mmd_mutex);
575 ret = -E_NO_AUDIO_FILE;
576 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
578 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
580 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
582 promille += 1000 * i / mmd->afd.afhi.seconds_total;
585 if (promille > 1000) {
586 mmd->new_vss_status_flags |= VSS_NEXT;
589 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
590 mmd->new_vss_status_flags |= VSS_REPOS;
591 mmd->new_vss_status_flags &= ~VSS_NEXT;
595 mutex_unlock(mmd_mutex);
600 int com_jmp(__a_unused struct rc4_context *rc4c, int argc, char * const * argv)
606 return -E_COMMAND_SYNTAX;
607 if (sscanf(argv[1], "%lu", &i) <= 0)
608 return -E_COMMAND_SYNTAX;
609 mutex_lock(mmd_mutex);
610 ret = -E_NO_AUDIO_FILE;
611 if (!mmd->afd.afhi.chunks_total)
615 PARA_INFO_LOG("jumping to %lu%%\n", i);
616 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
617 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
618 mmd->chunks_sent, mmd->offset);
619 mmd->new_vss_status_flags |= VSS_REPOS;
620 mmd->new_vss_status_flags &= ~VSS_NEXT;
624 mutex_unlock(mmd_mutex);
629 * check if perms are sufficient to exec a command having perms cmd_perms.
630 * Returns 0 if perms are sufficient, -E_PERM otherwise.
632 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
634 PARA_DEBUG_LOG("checking permissions\n");
635 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
639 * Parse first string from *cmd and lookup in table of valid commands.
640 * On error, NULL is returned.
642 static struct server_command *parse_cmd(const char *cmdstr)
647 sscanf(cmdstr, "%200s%n", buf, &n);
651 return get_cmd_ptr(buf, NULL);
654 static int read_command(struct rc4_context *rc4c, char **result)
658 char *command = NULL;
664 ret = rc4_recv_buffer(rc4c, buf, sizeof(buf));
670 ret = -E_COMMAND_SYNTAX;
671 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
673 command = para_strcat(command, buf);
674 p = strstr(command, EOC_MSG);
680 ret = command? 1 : -E_COMMAND_SYNTAX;
690 static void reset_signals(void)
692 para_sigaction(SIGCHLD, SIG_IGN);
693 para_sigaction(SIGINT, SIG_DFL);
694 para_sigaction(SIGTERM, SIG_DFL);
695 para_sigaction(SIGHUP, SIG_DFL);
699 * Perform user authentication and execute a command.
701 * \param fd The file descriptor to send output to.
702 * \param peername Identifies the connecting peer.
704 * Whenever para_server accepts an incoming tcp connection on
705 * the port it listens on, it forks and the resulting child
706 * calls this function.
708 * An RSA-based challenge/response is used to authenticate
709 * the peer. It that authentication succeeds, a random RC4
710 * session key is generated and sent back to the peer,
711 * encrypted with its RSA public key. From this point on,
712 * all transfers are crypted with this session key.
714 * Next it is checked if the peer supplied a valid server command or a command
715 * for the audio file selector. If yes, and if the user has sufficient
716 * permissions to execute that command, the function calls the corresponding
717 * command handler which does argument checking and further processing.
719 * In order to cope with a DOS attacks, a timeout is set up
720 * which terminates the function if the connection was not
721 * authenticated when the timeout expires.
723 * \sa alarm(2), rc4(3), crypt.c, crypt.h
725 __noreturn void handle_connect(int fd, const char *peername)
729 unsigned char rand_buf[CHALLENGE_SIZE + 2 * RC4_KEY_LEN];
730 unsigned char challenge_sha1[HASH_SIZE];
732 struct server_command *cmd = NULL;
734 char *p, *command = NULL;
736 struct rc4_context rc4c = {.fd = fd};
739 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
740 ret = mark_fd_blocking(fd);
743 /* send Welcome message */
744 ret = send_va_buffer(fd, "This is para_server, version "
745 PACKAGE_VERSION ".\n" );
748 /* recv auth request line */
749 ret = recv_buffer(fd, buf, sizeof(buf));
753 ret = -E_AUTH_REQUEST;
757 ret = -E_AUTH_REQUEST;
758 if (strncmp(buf, AUTH_REQUEST_MSG, strlen(AUTH_REQUEST_MSG)))
760 p = buf + strlen(AUTH_REQUEST_MSG);
761 PARA_DEBUG_LOG("received auth request for user %s\n", p);
765 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
766 ret = para_encrypt_buffer(u->rsa, rand_buf, sizeof(rand_buf),
767 (unsigned char *)buf);
773 * We don't want to reveal our user names, so we send a
774 * challenge to the client even if the user does not exist, and
775 * fail the authentication later.
778 get_random_bytes_or_die((unsigned char *)buf, numbytes);
780 PARA_DEBUG_LOG("sending %zu byte challenge + rc4 keys (%u bytes)\n",
781 CHALLENGE_SIZE, numbytes);
782 ret = send_bin_buffer(fd, buf, numbytes);
785 /* recv challenge response */
786 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
790 PARA_DEBUG_LOG("received %zu bytes challenge response\n", ret);
795 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
796 * of the random data.
799 if (numbytes != HASH_SIZE)
801 sha1_hash((char *)rand_buf, CHALLENGE_SIZE, challenge_sha1);
802 if (memcmp(challenge_sha1, buf, HASH_SIZE))
804 /* auth successful */
806 PARA_INFO_LOG("good auth for %s\n", u->name);
807 /* init rc4 keys with the second part of the random buffer */
808 RC4_set_key(&rc4c.recv_key, RC4_KEY_LEN, rand_buf + CHALLENGE_SIZE);
809 RC4_set_key(&rc4c.send_key, RC4_KEY_LEN, rand_buf + CHALLENGE_SIZE
811 ret = rc4_send_buffer(&rc4c, PROCEED_MSG);
814 ret = read_command(&rc4c, &command);
815 if (ret == -E_COMMAND_SYNTAX)
820 cmd = parse_cmd(command);
823 /* valid command, check permissions */
824 ret = check_perms(u->perms, cmd);
827 /* valid command and sufficient perms */
828 ret = create_argv(command, "\n", &argv);
832 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
834 ret = cmd->handler(&rc4c, argc, argv);
836 mutex_lock(mmd_mutex);
838 mutex_unlock(mmd_mutex);
842 rc4_send_va_buffer(&rc4c, "%s\n", para_strerror(-ret));
844 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
847 mutex_lock(mmd_mutex);
848 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
850 mmd->active_connections--;
851 mutex_unlock(mmd_mutex);
852 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);