2 * Copyright (C) 1997-2010 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>
21 #include "server.cmdline.h"
34 #include "user_list.h"
35 #include "server_command_list.h"
36 #include "afs_command_list.h"
40 /** Commands including options must be shorter than this. */
41 #define MAX_COMMAND_LEN 32768
44 extern struct misc_meta_data *mmd;
45 extern struct sender senders[];
46 int send_afs_status(struct rc4_context *rc4c, int parser_friendly);
48 const char *status_item_list[] = {STATUS_ITEM_ARRAY};
50 static void dummy(__a_unused int s)
54 static void mmd_dup(struct misc_meta_data *new_mmd)
56 mutex_lock(mmd_mutex);
58 mutex_unlock(mmd_mutex);
62 * Compute human readable string containing vss status for given integer value.
64 * We don't want to use vss_playing() and friends here because we take a
65 * snapshot of the mmd struct and use the copy for computing the state of the
66 * vss. If the real data were used, we would take the mmd lock for a rather
67 * long time or risk to get an inconsistent view.
69 static char *vss_status_tohuman(unsigned int flags)
71 if (flags & VSS_PLAYING)
72 return para_strdup("playing");
74 return para_strdup("stopped");
75 return para_strdup("paused");
79 * return human readable permission string. Never returns NULL.
81 static char *cmd_perms_itohuman(unsigned int perms)
83 char *msg = para_malloc(5 * sizeof(char));
85 msg[0] = perms & AFS_READ? 'a' : '-';
86 msg[1] = perms & AFS_WRITE? 'A' : '-';
87 msg[2] = perms & VSS_READ? 'v' : '-';
88 msg[3] = perms & VSS_WRITE? 'V' : '-';
96 static char *vss_get_status_flags(unsigned int flags)
98 char *msg = para_malloc(5 * sizeof(char));
100 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
101 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
102 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
103 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
108 static char *get_status(struct misc_meta_data *nmmd, int parser_friendly)
111 char *status, *flags; /* vss status info */
112 char *ut = uptime_str();
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);
126 WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
127 WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
128 WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
129 WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
130 WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
131 WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
132 WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
133 (long unsigned)nmmd->stream_start.tv_sec,
134 (long unsigned)nmmd->stream_start.tv_usec);
135 WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
136 (long unsigned)current_time.tv_sec,
137 (long unsigned)current_time.tv_usec);
144 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
147 /* this has to match sender.h */
148 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
150 scd->sender_num = -1;
152 return -E_COMMAND_SYNTAX;
153 for (i = 0; senders[i].name; i++)
154 if (!strcmp(senders[i].name, argv[1]))
156 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
157 if (!senders[i].name)
158 return -E_COMMAND_SYNTAX;
160 for (i = 0; subcmds[i]; i++)
161 if (!strcmp(subcmds[i], argv[2]))
164 return -E_COMMAND_SYNTAX;
166 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
167 return -E_SENDER_CMD;
168 switch (scd->cmd_num) {
172 return -E_COMMAND_SYNTAX;
176 if (argc != 4 || parse_cidr(argv[3], scd->host,
177 sizeof(scd->host), &scd->netmask) == NULL)
178 return -E_COMMAND_SYNTAX;
183 return -E_COMMAND_SYNTAX;
184 return parse_fec_url(argv[3], scd);
186 return -E_COMMAND_SYNTAX;
191 int com_sender(struct rc4_context *rc4c, int argc, char * const * argv)
194 struct sender_command_data scd;
198 for (i = 0; senders[i].name; i++) {
199 char *tmp = make_message("%s%s\n",
200 msg? msg : "", senders[i].name);
204 ret = rc4_send_buffer(rc4c, msg);
208 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);
218 for (i = 0; i < 10; i++) {
219 mutex_lock(mmd_mutex);
220 if (mmd->sender_cmd_data.cmd_num >= 0) {
221 mutex_unlock(mmd_mutex);
225 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
226 mutex_unlock(mmd_mutex);
229 return (i < 10)? 1 : -E_LOCK;
233 int com_si(struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
237 char *sender_info = NULL;
240 return -E_COMMAND_SYNTAX;
241 mutex_lock(mmd_mutex);
242 for (i = 0; senders[i].name; i++) {
243 char *info = senders[i].info();
244 sender_info = para_strcat(sender_info, info);
248 ret = rc4_send_va_buffer(rc4c, "up: %s\nplayed: %u\n"
251 "connections (active/accepted/total): %u/%u/%u\n"
252 "current loglevel: %s\n"
253 "supported audio formats: %s\n"
258 mmd->active_connections,
262 supported_audio_formats(),
265 mutex_unlock(mmd_mutex);
272 int com_version(struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
275 return -E_COMMAND_SYNTAX;
276 return rc4_send_buffer(rc4c, VERSION_TEXT("server")
277 "built: " BUILD_DATE "\n"
278 UNAME_RS ", " CC_VERSION "\n"
282 #define EMPTY_STATUS_ITEMS \
287 ITEM(ATTRIBUTES_BITMAP) \
288 ITEM(ATTRIBUTES_TXT) \
299 ITEM(SECONDS_TOTAL) \
311 * Write a list of audio-file related status items with empty values.
313 * This is used by vss when currently no audio file is open.
315 static char *empty_status_items(int parser_friendly)
319 #define ITEM(x) "0004 %02x:\n"
322 #define ITEM(x) , SI_ ## x
327 #define ITEM(x) "%s:\n"
330 #define ITEM(x) ,status_item_list[SI_ ## x]
335 #undef EMPTY_STATUS_ITEMS
338 int com_stat(struct rc4_context *rc4c, int argc, char * const * argv)
341 struct misc_meta_data tmp, *nmmd = &tmp;
344 int parser_friendly = 0;
346 para_sigaction(SIGUSR1, dummy);
348 for (i = 1; i < argc; i++) {
349 const char *arg = argv[i];
352 if (!strcmp(arg, "--")) {
356 if (!strncmp(arg, "-n=", 3)) {
357 ret = para_atoi32(arg + 3, &num);
362 if (!strcmp(arg, "-p")) {
366 return -E_COMMAND_SYNTAX;
369 return -E_COMMAND_SYNTAX;
372 s = get_status(nmmd, parser_friendly);
373 ret = rc4_send_buffer(rc4c, s);
377 if (nmmd->vss_status_flags & VSS_NEXT) {
380 esi = empty_status_items(parser_friendly);
381 ret = rc4_send_buffer(rc4c, esi);
385 send_afs_status(rc4c, parser_friendly);
387 if (num > 0 && !--num)
391 return -E_SERVER_CRASH;
397 static int send_list_of_commands(struct rc4_context *rc4c, struct server_command *cmd,
402 for (i = 1; cmd->name; cmd++, i++) {
403 char *perms = cmd_perms_itohuman(cmd->perms);
404 ret = rc4_send_va_buffer(rc4c, "%s\t%s\t%s\t%s\n", cmd->name,
415 /* returns string that must be freed by the caller */
416 static struct server_command *get_cmd_ptr(const char *name, char **handler)
418 struct server_command *cmd;
420 for (cmd = server_cmds; cmd->name; cmd++)
421 if (!strcmp(cmd->name, name)) {
423 *handler = para_strdup("server"); /* server commands */
426 /* not found, look for commands supported by afs */
427 for (cmd = afs_cmds; cmd->name; cmd++)
428 if (!strcmp(cmd->name, name)) {
430 *handler = para_strdup("afs");
437 int com_help(struct rc4_context *rc4c, int argc, char * const * argv)
439 struct server_command *cmd;
440 char *perms, *handler;
444 /* no argument given, print list of commands */
445 if ((ret = send_list_of_commands(rc4c, server_cmds, "server")) < 0)
447 return send_list_of_commands(rc4c, afs_cmds, "afs");
449 /* argument given for help */
450 cmd = get_cmd_ptr(argv[1], &handler);
455 perms = cmd_perms_itohuman(cmd->perms);
456 ret = rc4_send_va_buffer(rc4c,
475 int com_hup(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
478 return -E_COMMAND_SYNTAX;
479 kill(getppid(), SIGHUP);
484 int com_term(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
487 return -E_COMMAND_SYNTAX;
488 kill(getppid(), SIGTERM);
492 int com_play(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
495 return -E_COMMAND_SYNTAX;
496 mutex_lock(mmd_mutex);
497 mmd->new_vss_status_flags |= VSS_PLAYING;
498 mmd->new_vss_status_flags &= ~VSS_NOMORE;
499 mutex_unlock(mmd_mutex);
505 int com_stop(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
508 return -E_COMMAND_SYNTAX;
509 mutex_lock(mmd_mutex);
510 mmd->new_vss_status_flags &= ~VSS_PLAYING;
511 mmd->new_vss_status_flags &= ~VSS_REPOS;
512 mmd->new_vss_status_flags |= VSS_NEXT;
513 mutex_unlock(mmd_mutex);
518 int com_pause(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
521 return -E_COMMAND_SYNTAX;
522 mutex_lock(mmd_mutex);
523 if (!vss_paused() && !vss_stopped()) {
525 mmd->new_vss_status_flags &= ~VSS_PLAYING;
526 mmd->new_vss_status_flags &= ~VSS_NEXT;
528 mutex_unlock(mmd_mutex);
533 int com_next(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
536 return -E_COMMAND_SYNTAX;
537 mutex_lock(mmd_mutex);
539 mmd->new_vss_status_flags |= VSS_NEXT;
540 mutex_unlock(mmd_mutex);
545 int com_nomore(__a_unused struct rc4_context *rc4c, int argc, __a_unused char * const * argv)
548 return -E_COMMAND_SYNTAX;
549 mutex_lock(mmd_mutex);
550 if (vss_playing() || vss_paused())
551 mmd->new_vss_status_flags |= VSS_NOMORE;
552 mutex_unlock(mmd_mutex);
557 int com_ff(__a_unused struct rc4_context *rc4c, int argc, char * const * argv)
560 int ret, backwards = 0;
565 return -E_COMMAND_SYNTAX;
566 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
567 return -E_COMMAND_SYNTAX;
568 if (ret > 1 && c == '-')
569 backwards = 1; /* jmp backwards */
570 mutex_lock(mmd_mutex);
571 ret = -E_NO_AUDIO_FILE;
572 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
574 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
576 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
578 promille += 1000 * i / mmd->afd.afhi.seconds_total;
581 if (promille > 1000) {
582 mmd->new_vss_status_flags |= VSS_NEXT;
585 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
586 mmd->new_vss_status_flags |= VSS_REPOS;
587 mmd->new_vss_status_flags &= ~VSS_NEXT;
591 mutex_unlock(mmd_mutex);
596 int com_jmp(__a_unused struct rc4_context *rc4c, int argc, char * const * argv)
602 return -E_COMMAND_SYNTAX;
603 if (sscanf(argv[1], "%lu", &i) <= 0)
604 return -E_COMMAND_SYNTAX;
605 mutex_lock(mmd_mutex);
606 ret = -E_NO_AUDIO_FILE;
607 if (!mmd->afd.afhi.chunks_total)
611 PARA_INFO_LOG("jumping to %lu%%\n", i);
612 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
613 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
614 mmd->chunks_sent, mmd->offset);
615 mmd->new_vss_status_flags |= VSS_REPOS;
616 mmd->new_vss_status_flags &= ~VSS_NEXT;
620 mutex_unlock(mmd_mutex);
625 * check if perms are sufficient to exec a command having perms cmd_perms.
626 * Returns 0 if perms are sufficient, -E_PERM otherwise.
628 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
630 PARA_DEBUG_LOG("checking permissions\n");
631 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
635 * Parse first string from *cmd and lookup in table of valid commands.
636 * On error, NULL is returned.
638 static struct server_command *parse_cmd(const char *cmdstr)
643 sscanf(cmdstr, "%200s%n", buf, &n);
647 return get_cmd_ptr(buf, NULL);
650 static int read_command(struct rc4_context *rc4c, char **result)
654 char *command = NULL;
660 ret = rc4_recv_buffer(rc4c, buf, sizeof(buf));
666 ret = -E_COMMAND_SYNTAX;
667 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
669 command = para_strcat(command, buf);
670 p = strstr(command, EOC_MSG);
676 ret = command? 1 : -E_COMMAND_SYNTAX;
686 static void reset_signals(void)
688 para_sigaction(SIGCHLD, SIG_IGN);
689 para_sigaction(SIGINT, SIG_DFL);
690 para_sigaction(SIGTERM, SIG_DFL);
691 para_sigaction(SIGHUP, SIG_DFL);
695 * Perform user authentication and execute a command.
697 * \param fd The file descriptor to send output to.
698 * \param peername Identifies the connecting peer.
700 * Whenever para_server accepts an incoming tcp connection on
701 * the port it listens on, it forks and the resulting child
702 * calls this function.
704 * An RSA-based challenge/response is used to authenticate
705 * the peer. It that authentication succeeds, a random RC4
706 * session key is generated and sent back to the peer,
707 * encrypted with its RSA public key. From this point on,
708 * all transfers are crypted with this session key.
710 * Next it is checked if the peer supplied a valid server command or a command
711 * for the audio file selector. If yes, and if the user has sufficient
712 * permissions to execute that command, the function calls the corresponding
713 * command handler which does argument checking and further processing.
715 * In order to cope with a DOS attacks, a timeout is set up
716 * which terminates the function if the connection was not
717 * authenticated when the timeout expires.
719 * \sa alarm(2), rc4(3), crypt.c, crypt.h
721 __noreturn void handle_connect(int fd, const char *peername)
725 unsigned char rand_buf[CHALLENGE_SIZE + 2 * RC4_KEY_LEN];
726 unsigned char challenge_sha1[HASH_SIZE];
728 struct server_command *cmd = NULL;
730 char *p, *command = NULL;
732 struct rc4_context rc4c = {.fd = fd};
735 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
736 ret = mark_fd_blocking(fd);
739 /* send Welcome message */
740 ret = send_va_buffer(fd, "This is para_server, version "
741 PACKAGE_VERSION ".\n" );
744 /* recv auth request line */
745 ret = recv_buffer(fd, buf, sizeof(buf));
749 ret = -E_AUTH_REQUEST;
753 ret = -E_AUTH_REQUEST;
754 if (strncmp(buf, AUTH_REQUEST_MSG, strlen(AUTH_REQUEST_MSG)))
756 p = buf + strlen(AUTH_REQUEST_MSG);
757 PARA_DEBUG_LOG("received auth request for user %s\n", p);
761 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
762 ret = para_encrypt_buffer(u->rsa, rand_buf, sizeof(rand_buf),
763 (unsigned char *)buf);
769 * We don't want to reveal our user names, so we send a
770 * challenge to the client even if the user does not exist, and
771 * fail the authentication later.
774 get_random_bytes_or_die((unsigned char *)buf, numbytes);
776 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
777 CHALLENGE_SIZE, numbytes);
778 ret = send_bin_buffer(fd, buf, numbytes);
781 /* recv challenge response */
782 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
786 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret);
791 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
792 * of the random data.
795 if (numbytes != HASH_SIZE)
797 sha1_hash((char *)rand_buf, CHALLENGE_SIZE, challenge_sha1);
798 if (memcmp(challenge_sha1, buf, HASH_SIZE))
800 /* auth successful */
802 PARA_INFO_LOG("good auth for %s\n", u->name);
803 /* init rc4 keys with the second part of the random buffer */
804 RC4_set_key(&rc4c.recv_key, RC4_KEY_LEN, rand_buf + CHALLENGE_SIZE);
805 RC4_set_key(&rc4c.send_key, RC4_KEY_LEN, rand_buf + CHALLENGE_SIZE
807 ret = rc4_send_buffer(&rc4c, PROCEED_MSG);
810 ret = read_command(&rc4c, &command);
811 if (ret == -E_COMMAND_SYNTAX)
816 cmd = parse_cmd(command);
819 /* valid command, check permissions */
820 ret = check_perms(u->perms, cmd);
823 /* valid command and sufficient perms */
824 ret = create_argv(command, "\n", &argv);
828 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
830 ret = cmd->handler(&rc4c, argc, argv);
832 mutex_lock(mmd_mutex);
834 mutex_unlock(mmd_mutex);
838 rc4_send_va_buffer(&rc4c, "%s\n", para_strerror(-ret));
840 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
843 mutex_lock(mmd_mutex);
844 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
846 mmd->active_connections--;
847 mutex_unlock(mmd_mutex);
848 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);