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"
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 stream_cipher_context *scc, 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 stream_cipher_context *scc, int argc, char * const * argv)
194 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 = sc_send_buffer(scc, msg);
207 ret = check_sender_args(argc, argv, &scd);
209 if (scd.sender_num < 0)
211 msg = senders[scd.sender_num].help();
212 ret = sc_send_buffer(scc, msg);
217 switch (scd.cmd_num) {
220 assert(senders[scd.sender_num].resolve_target);
221 ret = senders[scd.sender_num].resolve_target(argv[3], &scd);
226 for (i = 0; i < 10; i++) {
227 mutex_lock(mmd_mutex);
228 if (mmd->sender_cmd_data.cmd_num >= 0) {
229 mutex_unlock(mmd_mutex);
233 memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
234 mutex_unlock(mmd_mutex);
237 return (i < 10)? 1 : -E_LOCK;
241 int com_si(struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
245 char *sender_info = NULL;
248 return -E_COMMAND_SYNTAX;
249 mutex_lock(mmd_mutex);
250 for (i = 0; senders[i].name; i++) {
251 char *info = senders[i].info();
252 sender_info = para_strcat(sender_info, info);
256 ret = sc_send_va_buffer(scc, "version: " GIT_VERSION "\n"
257 "up: %s\nplayed: %u\n"
260 "connections (active/accepted/total): %u/%u/%u\n"
261 "current loglevel: %s\n"
262 "supported audio formats: %s\n"
267 mmd->active_connections,
271 SERVER_AUDIO_FORMATS,
274 mutex_unlock(mmd_mutex);
281 int com_version(struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
284 return -E_COMMAND_SYNTAX;
285 return sc_send_buffer(scc, VERSION_TEXT("server")
286 "built: " BUILD_DATE "\n"
287 UNAME_RS ", " CC_VERSION "\n"
291 #define EMPTY_STATUS_ITEMS \
296 ITEM(ATTRIBUTES_BITMAP) \
297 ITEM(ATTRIBUTES_TXT) \
308 ITEM(SECONDS_TOTAL) \
320 * Write a list of audio-file related status items with empty values.
322 * This is used by vss when currently no audio file is open.
324 static char *empty_status_items(int parser_friendly)
328 #define ITEM(x) "0004 %02x:\n"
331 #define ITEM(x) , SI_ ## x
336 #define ITEM(x) "%s:\n"
339 #define ITEM(x) ,status_item_list[SI_ ## x]
344 #undef EMPTY_STATUS_ITEMS
347 int com_stat(struct stream_cipher_context *scc, int argc, char * const * argv)
350 struct misc_meta_data tmp, *nmmd = &tmp;
353 int parser_friendly = 0;
355 para_sigaction(SIGUSR1, dummy);
357 for (i = 1; i < argc; i++) {
358 const char *arg = argv[i];
361 if (!strcmp(arg, "--")) {
365 if (!strncmp(arg, "-n=", 3)) {
366 ret = para_atoi32(arg + 3, &num);
371 if (!strcmp(arg, "-p")) {
375 return -E_COMMAND_SYNTAX;
378 return -E_COMMAND_SYNTAX;
381 s = get_status(nmmd, parser_friendly);
382 ret = sc_send_buffer(scc, s);
386 if (nmmd->vss_status_flags & VSS_NEXT) {
389 esi = empty_status_items(parser_friendly);
390 ret = sc_send_buffer(scc, esi);
394 send_afs_status(scc, parser_friendly);
396 if (num > 0 && !--num)
400 return -E_SERVER_CRASH;
406 static int send_list_of_commands(struct stream_cipher_context *scc, struct server_command *cmd,
411 for (i = 1; cmd->name; cmd++, i++) {
412 char *perms = cmd_perms_itohuman(cmd->perms);
413 ret = sc_send_va_buffer(scc, "%s\t%s\t%s\t%s\n", cmd->name,
424 /* returns string that must be freed by the caller */
425 static struct server_command *get_cmd_ptr(const char *name, char **handler)
427 struct server_command *cmd;
429 for (cmd = server_cmds; cmd->name; cmd++)
430 if (!strcmp(cmd->name, name)) {
432 *handler = para_strdup("server"); /* server commands */
435 /* not found, look for commands supported by afs */
436 for (cmd = afs_cmds; cmd->name; cmd++)
437 if (!strcmp(cmd->name, name)) {
439 *handler = para_strdup("afs");
446 int com_help(struct stream_cipher_context *scc, int argc, char * const * argv)
448 struct server_command *cmd;
449 char *perms, *handler;
453 /* no argument given, print list of commands */
454 if ((ret = send_list_of_commands(scc, server_cmds, "server")) < 0)
456 return send_list_of_commands(scc, afs_cmds, "afs");
458 /* argument given for help */
459 cmd = get_cmd_ptr(argv[1], &handler);
462 perms = cmd_perms_itohuman(cmd->perms);
463 ret = sc_send_va_buffer(scc,
482 int com_hup(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
485 return -E_COMMAND_SYNTAX;
486 kill(getppid(), SIGHUP);
491 int com_term(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
494 return -E_COMMAND_SYNTAX;
495 kill(getppid(), SIGTERM);
499 int com_play(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
502 return -E_COMMAND_SYNTAX;
503 mutex_lock(mmd_mutex);
504 mmd->new_vss_status_flags |= VSS_PLAYING;
505 mmd->new_vss_status_flags &= ~VSS_NOMORE;
506 mutex_unlock(mmd_mutex);
512 int com_stop(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
515 return -E_COMMAND_SYNTAX;
516 mutex_lock(mmd_mutex);
517 mmd->new_vss_status_flags &= ~VSS_PLAYING;
518 mmd->new_vss_status_flags &= ~VSS_REPOS;
519 mmd->new_vss_status_flags |= VSS_NEXT;
520 mutex_unlock(mmd_mutex);
525 int com_pause(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
528 return -E_COMMAND_SYNTAX;
529 mutex_lock(mmd_mutex);
530 if (!vss_paused() && !vss_stopped()) {
532 mmd->new_vss_status_flags &= ~VSS_PLAYING;
533 mmd->new_vss_status_flags &= ~VSS_NEXT;
535 mutex_unlock(mmd_mutex);
540 int com_next(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
543 return -E_COMMAND_SYNTAX;
544 mutex_lock(mmd_mutex);
546 mmd->new_vss_status_flags |= VSS_NEXT;
547 mutex_unlock(mmd_mutex);
552 int com_nomore(__a_unused struct stream_cipher_context *scc, int argc, __a_unused char * const * argv)
555 return -E_COMMAND_SYNTAX;
556 mutex_lock(mmd_mutex);
557 if (vss_playing() || vss_paused())
558 mmd->new_vss_status_flags |= VSS_NOMORE;
559 mutex_unlock(mmd_mutex);
564 int com_ff(__a_unused struct stream_cipher_context *scc, int argc, char * const * argv)
567 int ret, backwards = 0;
572 return -E_COMMAND_SYNTAX;
573 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
574 return -E_COMMAND_SYNTAX;
575 if (ret > 1 && c == '-')
576 backwards = 1; /* jmp backwards */
577 mutex_lock(mmd_mutex);
578 ret = -E_NO_AUDIO_FILE;
579 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
581 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
583 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
585 promille += 1000 * i / mmd->afd.afhi.seconds_total;
588 if (promille > 1000) {
589 mmd->new_vss_status_flags |= VSS_NEXT;
592 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
593 mmd->new_vss_status_flags |= VSS_REPOS;
594 mmd->new_vss_status_flags &= ~VSS_NEXT;
598 mutex_unlock(mmd_mutex);
603 int com_jmp(__a_unused struct stream_cipher_context *scc, int argc, char * const * argv)
609 return -E_COMMAND_SYNTAX;
610 if (sscanf(argv[1], "%lu", &i) <= 0)
611 return -E_COMMAND_SYNTAX;
612 mutex_lock(mmd_mutex);
613 ret = -E_NO_AUDIO_FILE;
614 if (!mmd->afd.afhi.chunks_total)
618 PARA_INFO_LOG("jumping to %lu%%\n", i);
619 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
620 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
621 mmd->chunks_sent, mmd->offset);
622 mmd->new_vss_status_flags |= VSS_REPOS;
623 mmd->new_vss_status_flags &= ~VSS_NEXT;
627 mutex_unlock(mmd_mutex);
632 * check if perms are sufficient to exec a command having perms cmd_perms.
633 * Returns 0 if perms are sufficient, -E_PERM otherwise.
635 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
637 PARA_DEBUG_LOG("checking permissions\n");
638 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
642 * Parse first string from *cmd and lookup in table of valid commands.
643 * On error, NULL is returned.
645 static struct server_command *parse_cmd(const char *cmdstr)
650 sscanf(cmdstr, "%200s%n", buf, &n);
654 return get_cmd_ptr(buf, NULL);
657 static int read_command(struct stream_cipher_context *scc, char **result)
661 char *command = NULL;
667 ret = sc_recv_buffer(scc, buf, sizeof(buf));
673 ret = -E_COMMAND_SYNTAX;
674 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
676 command = para_strcat(command, buf);
677 p = strstr(command, EOC_MSG);
683 ret = command? 1 : -E_COMMAND_SYNTAX;
693 static void reset_signals(void)
695 para_sigaction(SIGCHLD, SIG_IGN);
696 para_sigaction(SIGINT, SIG_DFL);
697 para_sigaction(SIGTERM, SIG_DFL);
698 para_sigaction(SIGHUP, SIG_DFL);
702 * Perform user authentication and execute a command.
704 * \param fd The file descriptor to send output to.
705 * \param peername Identifies the connecting peer.
707 * Whenever para_server accepts an incoming tcp connection on
708 * the port it listens on, it forks and the resulting child
709 * calls this function.
711 * An RSA-based challenge/response is used to authenticate
712 * the peer. It that authentication succeeds, a random
713 * session key is generated and sent back to the peer,
714 * encrypted with its RSA public key. From this point on,
715 * all transfers are crypted with this session key.
717 * Next it is checked if the peer supplied a valid server command or a command
718 * for the audio file selector. If yes, and if the user has sufficient
719 * permissions to execute that command, the function calls the corresponding
720 * command handler which does argument checking and further processing.
722 * In order to cope with a DOS attacks, a timeout is set up
723 * which terminates the function if the connection was not
724 * authenticated when the timeout expires.
726 * \sa alarm(2), crypt.c, crypt.h
728 __noreturn void handle_connect(int fd, const char *peername)
732 unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
733 unsigned char challenge_hash[HASH_SIZE];
735 struct server_command *cmd = NULL;
737 char *p, *command = NULL;
739 struct stream_cipher_context scc = {.fd = fd};
742 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
743 ret = mark_fd_blocking(fd);
746 /* send Welcome message */
747 ret = send_va_buffer(fd, "This is para_server, version "
748 PACKAGE_VERSION ".\n" );
751 /* recv auth request line */
752 ret = recv_buffer(fd, buf, sizeof(buf));
756 ret = -E_AUTH_REQUEST;
760 ret = -E_AUTH_REQUEST;
761 if (strncmp(buf, AUTH_REQUEST_MSG, strlen(AUTH_REQUEST_MSG)))
763 p = buf + strlen(AUTH_REQUEST_MSG);
764 PARA_DEBUG_LOG("received auth request for user %s\n", p);
768 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
769 ret = pub_encrypt(u->pubkey, rand_buf, sizeof(rand_buf),
770 (unsigned char *)buf);
776 * We don't want to reveal our user names, so we send a
777 * challenge to the client even if the user does not exist, and
778 * fail the authentication later.
781 get_random_bytes_or_die((unsigned char *)buf, numbytes);
783 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
784 CHALLENGE_SIZE, numbytes);
785 ret = send_bin_buffer(fd, buf, numbytes);
788 /* recv challenge response */
789 ret = recv_bin_buffer(fd, buf, HASH_SIZE);
793 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret);
798 * The correct response is the hash of the first CHALLENGE_SIZE bytes
799 * of the random data.
802 if (numbytes != HASH_SIZE)
804 hash_function((char *)rand_buf, CHALLENGE_SIZE, challenge_hash);
805 if (memcmp(challenge_hash, buf, HASH_SIZE))
807 /* auth successful */
809 PARA_INFO_LOG("good auth for %s\n", u->name);
810 /* init stream cipher keys with the second part of the random buffer */
811 scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
812 scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN, SESSION_KEY_LEN);
813 ret = sc_send_buffer(&scc, PROCEED_MSG);
816 ret = read_command(&scc, &command);
817 if (ret == -E_COMMAND_SYNTAX)
822 cmd = parse_cmd(command);
825 /* valid command, check permissions */
826 ret = check_perms(u->perms, cmd);
829 /* valid command and sufficient perms */
830 ret = create_argv(command, "\n", &argv);
834 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
836 ret = cmd->handler(&scc, argc, argv);
838 mutex_lock(mmd_mutex);
840 mutex_unlock(mmd_mutex);
844 sc_send_va_buffer(&scc, "%s\n", para_strerror(-ret));
846 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
851 mutex_lock(mmd_mutex);
852 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
854 mmd->active_connections--;
855 mutex_unlock(mmd_mutex);
856 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);