2 * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file command.c does client authentication and executes server commands */
11 #include <sys/types.h>
13 #include <openssl/rc4.h>
17 #include "server.cmdline.h"
29 #include "user_list.h"
30 #include "server_command_list.h"
31 #include "afs_command_list.h"
33 /** commands including options must be shorter than this */
34 #define MAX_COMMAND_LEN 32768
36 static RC4_KEY rc4_recv_key;
37 static RC4_KEY rc4_send_key;
38 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
40 extern const char *status_item_list[NUM_STAT_ITEMS];
41 extern struct misc_meta_data *mmd;
42 extern struct sender senders[];
44 static void dummy(__a_unused int s)
47 static void mmd_dup(struct misc_meta_data *new_mmd)
55 * compute human readable string containing
56 * vss status for given integer value
58 static char *vss_status_tohuman(unsigned int flags)
60 if (flags & VSS_PLAYING)
61 return para_strdup("playing");
62 else if (flags & VSS_NEXT)
63 return para_strdup("stopped");
65 return para_strdup("paused");
69 * return human readable permission string. Never returns NULL.
71 static char *cmd_perms_itohuman(unsigned int perms)
73 char *msg = para_malloc(5 * sizeof(char));
75 msg[0] = perms & AFS_READ? 'a' : '-';
76 msg[1] = perms & AFS_WRITE? 'A' : '-';
77 msg[2] = perms & VSS_READ? 'v' : '-';
78 msg[3] = perms & VSS_WRITE? 'V' : '-';
86 static char *vss_get_status_flags(unsigned int flags)
88 char *msg = para_malloc(5 * sizeof(char));
90 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
91 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
92 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
93 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
99 * compute status bar string. Never returns NULL
101 static char *get_sb_string(struct misc_meta_data *nmmd)
104 long long unsigned secs = 0, rsecs = 0, percent = 0;
106 base = para_basename(nmmd->filename);
108 return para_strdup("");
111 if (nmmd->afi.chunks_total) {
112 secs = (long long) nmmd->afi.seconds_total * nmmd->chunks_sent
113 / nmmd->afi.chunks_total;
114 rsecs = (long long) nmmd->afi.seconds_total *
115 (nmmd->afi.chunks_total - nmmd->chunks_sent)
116 / nmmd->afi.chunks_total;
117 percent = 100 * ((nmmd->chunks_sent + 5) / 10)
118 / ((nmmd->afi.chunks_total + 5) / 10);
120 ret = make_message("%llu:%02llu [%llu:%02llu] (%llu%%) %s",
121 secs / 60, secs % 60,
122 rsecs / 60, rsecs % 60,
130 static char *get_status(struct misc_meta_data *nmmd)
132 char *bar, *ret, mtime[30] = "";
133 char *status, *flags; /* vss status info */
134 char *ut = uptime_str();
135 long offset = (nmmd->offset + 500) / 1000;
139 if (nmmd->audio_format >= 0) {
140 localtime_r(&nmmd->mtime, &mtime_tm);
141 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
143 /* report real status */
144 status = vss_status_tohuman(nmmd->vss_status_flags);
145 flags = vss_get_status_flags(nmmd->vss_status_flags);
146 bar = para_basename(nmmd->filename);
147 gettimeofday(&now, NULL);
149 "%s:%zu\n" "%s:%s\n" "%s:%lu\n" "%s:%u\n"
150 "%s:%s\n" "%s:%s\n" "%s:%s\n" "%s:%s\n"
151 "%s:%li\n" "%s:%s\n" "%s"
152 "%s:%s\n" "%s:%lu.%lu\n" "%s:%lu.%lu\n",
153 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
154 status_item_list[SI_MTIME], mtime,
155 status_item_list[SI_LENGTH], nmmd->afi.seconds_total,
156 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
158 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
159 status_item_list[SI_STATUS], status,
160 status_item_list[SI_STATUS_FLAGS], flags,
161 status_item_list[SI_SELECTOR], "FIXME",
163 status_item_list[SI_OFFSET], offset,
164 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
165 nmmd->afi.info_string,
167 status_item_list[SI_UPTIME], ut,
168 status_item_list[SI_STREAM_START],
169 (long unsigned)nmmd->stream_start.tv_sec,
170 (long unsigned)nmmd->stream_start.tv_usec,
171 status_item_list[SI_CURRENT_TIME],
172 (long unsigned)now.tv_sec,
173 (long unsigned)now.tv_usec
183 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
186 /* this has to match sender.h */
187 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
189 scd->sender_num = -1;
191 return -E_COMMAND_SYNTAX;
192 for (i = 0; senders[i].name; i++)
193 if (!strcmp(senders[i].name, argv[1]))
195 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
196 if (!senders[i].name)
197 return -E_COMMAND_SYNTAX;
199 for (i = 0; subcmds[i]; i++)
200 if (!strcmp(subcmds[i], argv[2]))
203 return -E_COMMAND_SYNTAX;
206 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
208 return -E_SENDER_CMD;
211 switch (scd->cmd_num) {
215 return -E_COMMAND_SYNTAX;
219 if (argc != 4 && argc != 5)
220 return -E_COMMAND_SYNTAX;
221 if (!inet_pton(AF_INET, argv[3], &scd->addr))
222 return -E_COMMAND_SYNTAX;
225 scd->netmask = atoi(argv[4]);
226 if (scd->netmask < 0 || scd->netmask > 32)
227 return -E_COMMAND_SYNTAX;
232 if (argc != 4 && argc != 5)
233 return -E_COMMAND_SYNTAX;
234 if (!inet_pton(AF_INET, argv[3], &scd->addr))
235 return -E_COMMAND_SYNTAX;
238 scd->port = atoi(argv[4]);
239 if (scd->port < 0 || scd->port > 65535)
240 return -E_COMMAND_SYNTAX;
244 return -E_COMMAND_SYNTAX;
249 int com_sender(int fd, int argc, char * const * argv)
252 struct sender_command_data scd;
256 for (i = 0; senders[i].name; i++) {
257 char *tmp = make_message("%s%s\n",
258 msg? msg : "", senders[i].name);
262 ret = send_buffer(fd, msg);
266 ret = check_sender_args(argc, argv, &scd);
269 if (scd.sender_num < 0)
271 msg = senders[scd.sender_num].help();
272 send_buffer(fd, msg);
276 for (i = 0; i < 10; i++) {
278 if (mmd->sender_cmd_data.cmd_num >= 0) {
283 mmd->sender_cmd_data = scd;
287 return (i < 10)? 1 : -E_LOCK;
291 int com_si(int fd, int argc, __a_unused char * const * argv)
295 char *sender_info = NULL, *sender_list = NULL;
298 return -E_COMMAND_SYNTAX;
300 for (i = 0; senders[i].name; i++) {
301 char *info = senders[i].info();
302 sender_info = para_strcat(sender_info, info);
304 sender_list = para_strcat(sender_list, senders[i].name);
305 sender_list = para_strcat(sender_list, " ");
308 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
310 "connections (active/accepted/total): %u/%u/%u\n"
311 "current loglevel: %i\n"
312 "supported audio formats: %s\n"
313 "supported senders: %s\n"
317 mmd->active_connections,
321 supported_audio_formats(),
333 int com_version(int fd, int argc, __a_unused char * const * argv)
336 return -E_COMMAND_SYNTAX;
337 return send_buffer(fd, VERSION_TEXT("server")
338 "built: " BUILD_DATE "\n"
339 SYSTEM ", " CC_VERSION "\n"
344 int com_sc(int fd, int argc, char * const * argv)
347 int ret, old = 0, count = -1; /* print af change forever */
350 count = atoi(argv[1]);
353 if (old != mmd->num_played) {
354 old = mmd->num_played;
355 name = para_strdup(mmd->filename);
359 ret = send_va_buffer(fd, "%s\n", name);
364 if (argc > 1 && !--count)
372 int com_sb(int fd, int argc, char * const * argv)
375 int ret, nr = -1; /* status bar will be printed that many
376 * times. Negative value means: print
383 sb = get_sb_string(mmd);
385 ret = send_va_buffer(fd, "%s\n", sb);
399 int com_stat(int fd, int argc, char * const * argv)
401 int ret, num = 0;/* status will be printed that many
402 * times. num <= 0 means: print forever
404 struct misc_meta_data tmp, *nmmd = &tmp;
407 signal(SIGUSR1, dummy);
414 s = get_status(nmmd);
415 ret = send_buffer(fd, s);
424 return -E_SERVER_CRASH;
430 static int send_list_of_commands(int fd, struct server_command *cmd,
435 for (i = 1; cmd->name; cmd++, i++) {
436 char *perms = cmd_perms_itohuman(cmd->perms);
437 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
448 /* always returns string that must be freed by the caller in handler */
449 static struct server_command *get_cmd_ptr(const char *name, char **handler)
451 struct server_command *cmd;
453 for (cmd = server_cmds; cmd->name; cmd++)
454 if (!strcmp(cmd->name, name)) {
456 *handler = para_strdup("para_server"); /* server commands */
459 /* not found, look for commands supported by afs */
460 for (cmd = afs_cmds; cmd->name; cmd++)
461 if (!strcmp(cmd->name, name))
467 int com_help(int fd, int argc, char * const * argv)
469 struct server_command *cmd;
470 char *perms, *handler;
474 /* no argument given, print list of commands */
475 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
477 return send_list_of_commands(fd, afs_cmds, "afs");
479 /* argument given for help */
480 cmd = get_cmd_ptr(argv[1], &handler);
485 perms = cmd_perms_itohuman(cmd->perms);
486 ret = send_va_buffer(fd,
505 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
508 return -E_COMMAND_SYNTAX;
509 kill(getppid(), SIGHUP);
514 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
517 return -E_COMMAND_SYNTAX;
518 kill(getppid(), SIGTERM);
522 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
525 return -E_COMMAND_SYNTAX;
527 mmd->new_vss_status_flags |= VSS_PLAYING;
528 mmd->new_vss_status_flags &= ~VSS_NOMORE;
535 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
538 return -E_COMMAND_SYNTAX;
540 mmd->new_vss_status_flags &= ~VSS_PLAYING;
541 mmd->new_vss_status_flags &= ~VSS_REPOS;
542 mmd->new_vss_status_flags |= VSS_NEXT;
548 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
551 return -E_COMMAND_SYNTAX;
555 mmd->new_vss_status_flags &= ~VSS_PLAYING;
556 mmd->new_vss_status_flags &= ~VSS_NEXT;
562 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
565 return -E_COMMAND_SYNTAX;
568 mmd->new_vss_status_flags |= VSS_NEXT;
574 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
577 return -E_COMMAND_SYNTAX;
579 if (vss_playing() || vss_paused())
580 mmd->new_vss_status_flags |= VSS_NOMORE;
586 int com_ff(__a_unused int fd, int argc, char * const * argv)
589 int ret, backwards = 0;
594 return -E_COMMAND_SYNTAX;
595 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
596 return -E_COMMAND_SYNTAX;
597 if (ret > 1 && c == '-')
598 backwards = 1; /* jmp backwards */
600 ret = -E_NO_AUDIO_FILE;
601 if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
603 promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
605 promille -= 1000 * i / mmd->afi.seconds_total;
607 promille += 1000 * i / mmd->afi.seconds_total;
610 if (promille > 1000) {
611 mmd->new_vss_status_flags |= VSS_NEXT;
614 mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
615 mmd->new_vss_status_flags |= VSS_REPOS;
616 mmd->new_vss_status_flags &= ~VSS_NEXT;
625 int com_jmp(__a_unused int fd, int argc, char * const * argv)
631 return -E_COMMAND_SYNTAX;
632 if (sscanf(argv[1], "%lu", &i) <= 0)
633 return -E_COMMAND_SYNTAX;
635 ret = -E_NO_AUDIO_FILE;
636 if (!mmd->afi.chunks_total)
640 PARA_INFO_LOG("jumping to %lu%%\n", i);
641 mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
642 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
643 mmd->chunks_sent, mmd->offset);
644 mmd->new_vss_status_flags |= VSS_REPOS;
645 mmd->new_vss_status_flags &= ~VSS_NEXT;
654 * check if perms are sufficient to exec a command having perms cmd_perms.
655 * Returns 0 if perms are sufficient, -E_PERM otherwise.
657 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
659 PARA_DEBUG_LOG("%s", "checking permissions\n");
660 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
664 * Parse first string from *cmd and lookup in table of valid commands.
665 * On error, NULL is returned.
667 static struct server_command *parse_cmd(const char *cmdstr)
672 sscanf(cmdstr, "%200s%n", buf, &n);
676 return get_cmd_ptr(buf, NULL);
679 static long int para_rand(long unsigned max)
681 return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
684 static void init_rc4_keys(void)
688 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
689 rc4_buf[i] = para_rand(256);
690 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
691 (unsigned char) rc4_buf[0],
692 (unsigned char) rc4_buf[RC4_KEY_LEN]);
693 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
694 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
697 static void rc4_recv(unsigned long len, const unsigned char *indata,
698 unsigned char *outdata, __a_unused void *private_data)
700 RC4(&rc4_recv_key, len, indata, outdata);
703 static void rc4_send(unsigned long len, const unsigned char *indata,
704 unsigned char *outdata, __a_unused void *private_data)
706 RC4(&rc4_send_key, len, indata, outdata);
709 static int read_command(int fd, char **result)
713 char *command = NULL;
719 ret = recv_buffer(fd, buf, sizeof(buf));
725 ret = -E_COMMAND_SYNTAX;
726 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
728 command = para_strcat(command, buf);
729 p = strstr(command, EOC_MSG);
735 ret = command? 1 : -E_COMMAND_SYNTAX;
746 * perform user authentication and execute a command
748 * \param fd the file descriptor to send output to
749 * \param addr socket address info of peer
751 * \return EXIT_SUCCESS or EXIT_FAILURE
753 * Whenever para_server accepts an incoming tcp connection on
754 * the port it listens on, it forks and the resulting child
755 * calls this function.
757 * An RSA-based challenge/response is used to authenticate
758 * the peer. It that authentication succeeds, a random RC4
759 * session key is generated and sent back to the peer,
760 * encrypted with its RSA public key. From this point on,
761 * all transfers are crypted with this session key.
763 * Next it is checked if the peer supplied a valid server command or a command
764 * for the audio file selector. If yes, and if the user has sufficient
765 * permissions to execute that command, the function calls the corresponding
766 * command handler which does argument checking and further processing.
768 * In order to cope with a DOS attacks, a timeout is set up
769 * which terminates the function if the connection was not
770 * authenticated when the timeout expires.
772 * \sa alarm(2), rc4(3), crypt.c, crypt.h
774 int handle_connect(int fd, struct sockaddr_in *addr)
776 int ret, argc, use_rc4 = 0;
778 unsigned char crypt_buf[MAXLINE];
780 struct server_command *cmd = NULL;
781 long unsigned challenge_nr, chall_response;
783 char *p, *command = NULL;
786 signal(SIGCHLD, SIG_IGN);
787 signal(SIGINT, SIG_DFL);
788 signal(SIGTERM, SIG_DFL);
789 signal(SIGHUP, SIG_DFL);
790 signal(SIGUSR1, SIG_IGN);
792 challenge_nr = random();
793 /* send Welcome message */
794 ret = send_va_buffer(fd, "This is para_server, version "
795 PACKAGE_VERSION ".\n" );
798 /* recv auth request line */
799 ret = recv_buffer(fd, buf, sizeof(buf));
808 if (strncmp(buf, "auth ", 5))
811 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
812 p = buf + 5; /* client version < 0.2.6 */
814 p = buf + 9; /* client version >= 0.2.6 */
817 PARA_DEBUG_LOG("received %s request for user %s\n",
818 use_rc4? "rc4" : "auth", p);
823 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
827 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
828 /* We can't use send_buffer here since buf may contain null bytes */
829 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
832 /* recv decrypted number */
833 ret = recv_buffer(fd, buf, sizeof(buf));
840 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
841 || chall_response != challenge_nr)
843 /* auth successful, send 'Proceed' message */
844 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
845 sprintf(buf, "%s", PROCEED_MSG);
848 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
849 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
852 numbytes = ret + strlen(PROCEED_MSG) + 1;
854 numbytes = strlen(buf);
855 ret = send_bin_buffer(fd, buf, numbytes);
859 enable_crypt(fd, rc4_recv, rc4_send, NULL);
860 ret = read_command(fd, &command);
864 cmd = parse_cmd(command);
867 /* valid command, check permissions */
868 ret = check_perms(u->perms, cmd);
871 /* valid command and sufficient perms */
873 argc = split_args(command, &argv, "\n");
877 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
878 inet_ntoa(addr->sin_addr));
879 ret = cmd->handler(fd, argc, argv);
885 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
886 if (ret != -E_SEND && ret != -E_RECV)
887 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
893 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
895 mmd->active_connections--;