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 Client authentication and 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:%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 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
166 nmmd->afi.info_string,
168 status_item_list[SI_UPTIME], ut,
169 status_item_list[SI_STREAM_START],
170 (long unsigned)nmmd->stream_start.tv_sec,
171 (long unsigned)nmmd->stream_start.tv_usec,
172 status_item_list[SI_CURRENT_TIME],
173 (long unsigned)now.tv_sec,
174 (long unsigned)now.tv_usec
184 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
187 /* this has to match sender.h */
188 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
190 scd->sender_num = -1;
192 return -E_COMMAND_SYNTAX;
193 for (i = 0; senders[i].name; i++)
194 if (!strcmp(senders[i].name, argv[1]))
196 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
197 if (!senders[i].name)
198 return -E_COMMAND_SYNTAX;
200 for (i = 0; subcmds[i]; i++)
201 if (!strcmp(subcmds[i], argv[2]))
204 return -E_COMMAND_SYNTAX;
207 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
209 return -E_SENDER_CMD;
212 switch (scd->cmd_num) {
216 return -E_COMMAND_SYNTAX;
220 if (argc != 4 && argc != 5)
221 return -E_COMMAND_SYNTAX;
222 if (!inet_pton(AF_INET, argv[3], &scd->addr))
223 return -E_COMMAND_SYNTAX;
226 scd->netmask = atoi(argv[4]);
227 if (scd->netmask < 0 || scd->netmask > 32)
228 return -E_COMMAND_SYNTAX;
233 if (argc != 4 && argc != 5)
234 return -E_COMMAND_SYNTAX;
235 if (!inet_pton(AF_INET, argv[3], &scd->addr))
236 return -E_COMMAND_SYNTAX;
239 scd->port = atoi(argv[4]);
240 if (scd->port < 0 || scd->port > 65535)
241 return -E_COMMAND_SYNTAX;
245 return -E_COMMAND_SYNTAX;
250 int com_sender(int fd, int argc, char * const * argv)
253 struct sender_command_data scd;
257 for (i = 0; senders[i].name; i++) {
258 char *tmp = make_message("%s%s\n",
259 msg? msg : "", senders[i].name);
263 ret = send_buffer(fd, msg);
267 ret = check_sender_args(argc, argv, &scd);
270 if (scd.sender_num < 0)
272 msg = senders[scd.sender_num].help();
273 send_buffer(fd, msg);
277 for (i = 0; i < 10; i++) {
279 if (mmd->sender_cmd_data.cmd_num >= 0) {
284 mmd->sender_cmd_data = scd;
288 return (i < 10)? 1 : -E_LOCK;
292 int com_si(int fd, int argc, __a_unused char * const * argv)
296 char *sender_info = NULL, *sender_list = NULL;
299 return -E_COMMAND_SYNTAX;
301 for (i = 0; senders[i].name; i++) {
302 char *info = senders[i].info();
303 sender_info = para_strcat(sender_info, info);
305 sender_list = para_strcat(sender_list, senders[i].name);
306 sender_list = para_strcat(sender_list, " ");
309 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
311 "connections (active/accepted/total): %u/%u/%u\n"
312 "current loglevel: %i\n"
313 "supported audio formats: %s\n"
314 "supported senders: %s\n"
318 mmd->active_connections,
322 supported_audio_formats(),
334 int com_version(int fd, int argc, __a_unused char * const * argv)
337 return -E_COMMAND_SYNTAX;
338 return send_buffer(fd, VERSION_TEXT("server")
339 "built: " BUILD_DATE "\n"
340 SYSTEM ", " CC_VERSION "\n"
345 int com_sc(int fd, int argc, char * const * argv)
348 int ret, old = 0, count = -1; /* print af change forever */
351 count = atoi(argv[1]);
354 if (old != mmd->num_played) {
355 old = mmd->num_played;
356 name = para_strdup(mmd->filename);
360 ret = send_va_buffer(fd, "%s\n", name);
365 if (argc > 1 && !--count)
373 int com_sb(int fd, int argc, char * const * argv)
376 int ret, nr = -1; /* status bar will be printed that many
377 * times. Negative value means: print
384 sb = get_sb_string(mmd);
386 ret = send_va_buffer(fd, "%s\n", sb);
400 int com_stat(int fd, int argc, char * const * argv)
402 int ret, num = 0;/* status will be printed that many
403 * times. num <= 0 means: print forever
405 struct misc_meta_data tmp, *nmmd = &tmp;
408 signal(SIGUSR1, dummy);
415 s = get_status(nmmd);
416 ret = send_buffer(fd, s);
425 return -E_SERVER_CRASH;
431 static int send_list_of_commands(int fd, struct server_command *cmd,
436 for (i = 1; cmd->name; cmd++, i++) {
437 char *perms = cmd_perms_itohuman(cmd->perms);
438 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
449 /* returns string that must be freed by the caller */
450 static struct server_command *get_cmd_ptr(const char *name, char **handler)
452 struct server_command *cmd;
454 for (cmd = server_cmds; cmd->name; cmd++)
455 if (!strcmp(cmd->name, name)) {
457 *handler = para_strdup("para_server"); /* server commands */
460 /* not found, look for commands supported by afs */
461 for (cmd = afs_cmds; cmd->name; cmd++)
462 if (!strcmp(cmd->name, name))
468 int com_help(int fd, int argc, char * const * argv)
470 struct server_command *cmd;
471 char *perms, *handler;
475 /* no argument given, print list of commands */
476 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
478 return send_list_of_commands(fd, afs_cmds, "afs");
480 /* argument given for help */
481 cmd = get_cmd_ptr(argv[1], &handler);
486 perms = cmd_perms_itohuman(cmd->perms);
487 ret = send_va_buffer(fd,
506 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
509 return -E_COMMAND_SYNTAX;
510 kill(getppid(), SIGHUP);
515 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
518 return -E_COMMAND_SYNTAX;
519 kill(getppid(), SIGTERM);
523 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
526 return -E_COMMAND_SYNTAX;
528 mmd->new_vss_status_flags |= VSS_PLAYING;
529 mmd->new_vss_status_flags &= ~VSS_NOMORE;
536 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
539 return -E_COMMAND_SYNTAX;
541 mmd->new_vss_status_flags &= ~VSS_PLAYING;
542 mmd->new_vss_status_flags &= ~VSS_REPOS;
543 mmd->new_vss_status_flags |= VSS_NEXT;
549 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
552 return -E_COMMAND_SYNTAX;
556 mmd->new_vss_status_flags &= ~VSS_PLAYING;
557 mmd->new_vss_status_flags &= ~VSS_NEXT;
563 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
566 return -E_COMMAND_SYNTAX;
569 mmd->new_vss_status_flags |= VSS_NEXT;
575 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
578 return -E_COMMAND_SYNTAX;
580 if (vss_playing() || vss_paused())
581 mmd->new_vss_status_flags |= VSS_NOMORE;
587 int com_ff(__a_unused int fd, int argc, char * const * argv)
590 int ret, backwards = 0;
595 return -E_COMMAND_SYNTAX;
596 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
597 return -E_COMMAND_SYNTAX;
598 if (ret > 1 && c == '-')
599 backwards = 1; /* jmp backwards */
601 ret = -E_NO_AUDIO_FILE;
602 if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
604 promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
606 promille -= 1000 * i / mmd->afi.seconds_total;
608 promille += 1000 * i / mmd->afi.seconds_total;
611 if (promille > 1000) {
612 mmd->new_vss_status_flags |= VSS_NEXT;
615 mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
616 mmd->new_vss_status_flags |= VSS_REPOS;
617 mmd->new_vss_status_flags &= ~VSS_NEXT;
626 int com_jmp(__a_unused int fd, int argc, char * const * argv)
632 return -E_COMMAND_SYNTAX;
633 if (sscanf(argv[1], "%lu", &i) <= 0)
634 return -E_COMMAND_SYNTAX;
636 ret = -E_NO_AUDIO_FILE;
637 if (!mmd->afi.chunks_total)
641 PARA_INFO_LOG("jumping to %lu%%\n", i);
642 mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
643 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
644 mmd->chunks_sent, mmd->offset);
645 mmd->new_vss_status_flags |= VSS_REPOS;
646 mmd->new_vss_status_flags &= ~VSS_NEXT;
655 * check if perms are sufficient to exec a command having perms cmd_perms.
656 * Returns 0 if perms are sufficient, -E_PERM otherwise.
658 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
660 PARA_DEBUG_LOG("%s", "checking permissions\n");
661 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
665 * Parse first string from *cmd and lookup in table of valid commands.
666 * On error, NULL is returned.
668 static struct server_command *parse_cmd(const char *cmdstr)
673 sscanf(cmdstr, "%200s%n", buf, &n);
677 return get_cmd_ptr(buf, NULL);
680 static long int para_rand(long unsigned max)
682 return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
685 static void init_rc4_keys(void)
689 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
690 rc4_buf[i] = para_rand(256);
691 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
692 (unsigned char) rc4_buf[0],
693 (unsigned char) rc4_buf[RC4_KEY_LEN]);
694 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
695 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
698 static void rc4_recv(unsigned long len, const unsigned char *indata,
699 unsigned char *outdata, __a_unused void *private_data)
701 RC4(&rc4_recv_key, len, indata, outdata);
704 static void rc4_send(unsigned long len, const unsigned char *indata,
705 unsigned char *outdata, __a_unused void *private_data)
707 RC4(&rc4_send_key, len, indata, outdata);
710 static int read_command(int fd, char **result)
714 char *command = NULL;
720 ret = recv_buffer(fd, buf, sizeof(buf));
726 ret = -E_COMMAND_SYNTAX;
727 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
729 command = para_strcat(command, buf);
730 p = strstr(command, EOC_MSG);
736 ret = command? 1 : -E_COMMAND_SYNTAX;
747 * perform user authentication and execute a command
749 * \param fd the file descriptor to send output to
750 * \param addr socket address info of peer
752 * \return EXIT_SUCCESS or EXIT_FAILURE
754 * Whenever para_server accepts an incoming tcp connection on
755 * the port it listens on, it forks and the resulting child
756 * calls this function.
758 * An RSA-based challenge/response is used to authenticate
759 * the peer. It that authentication succeeds, a random RC4
760 * session key is generated and sent back to the peer,
761 * encrypted with its RSA public key. From this point on,
762 * all transfers are crypted with this session key.
764 * Next it is checked if the peer supplied a valid server command or a command
765 * for the audio file selector. If yes, and if the user has sufficient
766 * permissions to execute that command, the function calls the corresponding
767 * command handler which does argument checking and further processing.
769 * In order to cope with a DOS attacks, a timeout is set up
770 * which terminates the function if the connection was not
771 * authenticated when the timeout expires.
773 * \sa alarm(2), rc4(3), crypt.c, crypt.h
775 int handle_connect(int fd, struct sockaddr_in *addr)
777 int ret, argc, use_rc4 = 0;
779 unsigned char crypt_buf[MAXLINE];
781 struct server_command *cmd = NULL;
782 long unsigned challenge_nr, chall_response;
784 char *p, *command = NULL;
787 signal(SIGCHLD, SIG_IGN);
788 signal(SIGINT, SIG_DFL);
789 signal(SIGTERM, SIG_DFL);
790 signal(SIGHUP, SIG_DFL);
791 signal(SIGUSR1, SIG_IGN);
793 challenge_nr = random();
794 /* send Welcome message */
795 ret = send_va_buffer(fd, "This is para_server, version "
796 PACKAGE_VERSION ".\n" );
799 /* recv auth request line */
800 ret = recv_buffer(fd, buf, sizeof(buf));
809 if (strncmp(buf, "auth ", 5))
812 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
813 p = buf + 5; /* client version < 0.2.6 */
815 p = buf + 9; /* client version >= 0.2.6 */
818 PARA_DEBUG_LOG("received %s request for user %s\n",
819 use_rc4? "rc4" : "auth", p);
824 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
828 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
829 /* We can't use send_buffer here since buf may contain null bytes */
830 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
833 /* recv decrypted number */
834 ret = recv_buffer(fd, buf, sizeof(buf));
841 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
842 || chall_response != challenge_nr)
844 /* auth successful, send 'Proceed' message */
845 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
846 sprintf(buf, "%s", PROCEED_MSG);
849 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
850 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
853 numbytes = ret + strlen(PROCEED_MSG) + 1;
855 numbytes = strlen(buf);
856 ret = send_bin_buffer(fd, buf, numbytes);
860 enable_crypt(fd, rc4_recv, rc4_send, NULL);
861 ret = read_command(fd, &command);
865 cmd = parse_cmd(command);
868 /* valid command, check permissions */
869 ret = check_perms(u->perms, cmd);
872 /* valid command and sufficient perms */
874 argc = split_args(command, &argv, "\n");
878 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
879 inet_ntoa(addr->sin_addr));
880 ret = cmd->handler(fd, argc, argv);
886 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
887 if (ret != -E_SEND && ret != -E_RECV)
888 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
894 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
896 mmd->active_connections--;