2 * Copyright (C) 1997-2008 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 struct misc_meta_data *mmd;
41 extern struct sender senders[];
43 static void dummy(int s)
46 * At least on Solaris, SIGUSR1 is one-shot, i.e. the signal action is
47 * restored to the default state once the signal handler has been
51 signal(SIGUSR1, dummy);
54 static void mmd_dup(struct misc_meta_data *new_mmd)
62 * compute human readable string containing
63 * vss status for given integer value
65 static char *vss_status_tohuman(unsigned int flags)
67 if (flags & VSS_PLAYING)
68 return para_strdup("playing");
69 else if (flags & VSS_NEXT)
70 return para_strdup("stopped");
72 return para_strdup("paused");
76 * return human readable permission string. Never returns NULL.
78 static char *cmd_perms_itohuman(unsigned int perms)
80 char *msg = para_malloc(5 * sizeof(char));
82 msg[0] = perms & AFS_READ? 'a' : '-';
83 msg[1] = perms & AFS_WRITE? 'A' : '-';
84 msg[2] = perms & VSS_READ? 'v' : '-';
85 msg[3] = perms & VSS_WRITE? 'V' : '-';
93 static char *vss_get_status_flags(unsigned int flags)
95 char *msg = para_malloc(5 * sizeof(char));
97 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
98 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
99 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
100 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
105 static char *get_status(struct misc_meta_data *nmmd)
107 char *ret, mtime[30] = "";
108 char *status, *flags; /* vss status info */
109 char *ut = uptime_str();
110 long offset = (nmmd->offset + 500) / 1000;
114 /* report real status */
115 status = vss_status_tohuman(nmmd->vss_status_flags);
116 flags = vss_get_status_flags(nmmd->vss_status_flags);
117 if (nmmd->size) { /* parent currently has an audio file open */
118 localtime_r(&nmmd->mtime, &mtime_tm);
119 strftime(mtime, 29, "%b %d %Y", &mtime_tm);
121 gettimeofday(&now, NULL);
123 "%s: %zu\n" /* file size */
124 "%s: %s\n" /* mtime */
125 "%s: %s\n" /* status */
126 "%s: %s\n" /* status flags */
127 "%s: %li\n" /* offset */
128 "%s: %s\n" /* afs mode */
129 "%s: %lu.%lu\n" /* stream start */
130 "%s: %lu.%lu\n" /* current server time */
131 "%s", /* afs status info */
132 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
133 status_item_list[SI_MTIME], mtime,
134 status_item_list[SI_STATUS], status,
135 status_item_list[SI_STATUS_FLAGS], flags,
137 status_item_list[SI_OFFSET], offset,
138 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
140 status_item_list[SI_STREAM_START],
141 (long unsigned)nmmd->stream_start.tv_sec,
142 (long unsigned)nmmd->stream_start.tv_usec,
143 status_item_list[SI_CURRENT_TIME],
144 (long unsigned)now.tv_sec,
145 (long unsigned)now.tv_usec,
147 nmmd->afd.verbose_ls_output
156 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
159 /* this has to match sender.h */
160 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
162 scd->sender_num = -1;
164 return -E_COMMAND_SYNTAX;
165 for (i = 0; senders[i].name; i++)
166 if (!strcmp(senders[i].name, argv[1]))
168 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
169 if (!senders[i].name)
170 return -E_COMMAND_SYNTAX;
172 for (i = 0; subcmds[i]; i++)
173 if (!strcmp(subcmds[i], argv[2]))
176 return -E_COMMAND_SYNTAX;
179 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
181 return -E_SENDER_CMD;
184 switch (scd->cmd_num) {
188 return -E_COMMAND_SYNTAX;
192 if (argc != 4 && argc != 5)
193 return -E_COMMAND_SYNTAX;
194 if (!inet_pton(AF_INET, argv[3], &scd->addr))
195 return -E_COMMAND_SYNTAX;
198 scd->netmask = atoi(argv[4]);
199 if (scd->netmask < 0 || scd->netmask > 32)
200 return -E_COMMAND_SYNTAX;
205 if (argc != 4 && argc != 5)
206 return -E_COMMAND_SYNTAX;
207 if (!inet_pton(AF_INET, argv[3], &scd->addr))
208 return -E_COMMAND_SYNTAX;
211 scd->port = atoi(argv[4]);
212 if (scd->port < 0 || scd->port > 65535)
213 return -E_COMMAND_SYNTAX;
217 return -E_COMMAND_SYNTAX;
222 int com_sender(int fd, int argc, char * const * argv)
225 struct sender_command_data scd;
229 for (i = 0; senders[i].name; i++) {
230 char *tmp = make_message("%s%s\n",
231 msg? msg : "", senders[i].name);
235 ret = send_buffer(fd, msg);
239 ret = check_sender_args(argc, argv, &scd);
242 if (scd.sender_num < 0)
244 msg = senders[scd.sender_num].help();
245 ret = send_buffer(fd, msg);
249 for (i = 0; i < 10; i++) {
251 if (mmd->sender_cmd_data.cmd_num >= 0) {
256 mmd->sender_cmd_data = scd;
260 return (i < 10)? 1 : -E_LOCK;
264 int com_si(int fd, int argc, __a_unused char * const * argv)
268 char *sender_info = NULL, *sender_list = NULL;
271 return -E_COMMAND_SYNTAX;
273 for (i = 0; senders[i].name; i++) {
274 char *info = senders[i].info();
275 sender_info = para_strcat(sender_info, info);
277 sender_list = para_strcat(sender_list, senders[i].name);
278 sender_list = para_strcat(sender_list, " ");
281 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
283 "connections (active/accepted/total): %u/%u/%u\n"
284 "current loglevel: %i\n"
285 "supported audio formats: %s\n"
286 "supported senders: %s\n"
290 mmd->active_connections,
294 supported_audio_formats(),
306 int com_version(int fd, int argc, __a_unused char * const * argv)
309 return -E_COMMAND_SYNTAX;
310 return send_buffer(fd, VERSION_TEXT("server")
311 "built: " BUILD_DATE "\n"
312 UNAME_RS ", " CC_VERSION "\n"
317 int com_stat(int fd, int argc, char * const * argv)
319 int ret, num = 0;/* status will be printed that many
320 * times. num <= 0 means: print forever
322 struct misc_meta_data tmp, *nmmd = &tmp;
325 signal(SIGUSR1, dummy);
332 s = get_status(nmmd);
333 ret = send_buffer(fd, s);
338 if (num > 0 && !--num)
342 return -E_SERVER_CRASH;
348 static int send_list_of_commands(int fd, struct server_command *cmd,
353 for (i = 1; cmd->name; cmd++, i++) {
354 char *perms = cmd_perms_itohuman(cmd->perms);
355 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
366 /* returns string that must be freed by the caller */
367 static struct server_command *get_cmd_ptr(const char *name, char **handler)
369 struct server_command *cmd;
371 for (cmd = server_cmds; cmd->name; cmd++)
372 if (!strcmp(cmd->name, name)) {
374 *handler = para_strdup("server"); /* server commands */
377 /* not found, look for commands supported by afs */
378 for (cmd = afs_cmds; cmd->name; cmd++)
379 if (!strcmp(cmd->name, name)) {
381 *handler = para_strdup("afs");
388 int com_help(int fd, int argc, char * const * argv)
390 struct server_command *cmd;
391 char *perms, *handler;
395 /* no argument given, print list of commands */
396 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
398 return send_list_of_commands(fd, afs_cmds, "afs");
400 /* argument given for help */
401 cmd = get_cmd_ptr(argv[1], &handler);
406 perms = cmd_perms_itohuman(cmd->perms);
407 ret = send_va_buffer(fd,
426 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
429 return -E_COMMAND_SYNTAX;
430 kill(getppid(), SIGHUP);
435 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
438 return -E_COMMAND_SYNTAX;
439 kill(getppid(), SIGTERM);
443 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
446 return -E_COMMAND_SYNTAX;
448 mmd->new_vss_status_flags |= VSS_PLAYING;
449 mmd->new_vss_status_flags &= ~VSS_NOMORE;
456 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
459 return -E_COMMAND_SYNTAX;
461 mmd->new_vss_status_flags &= ~VSS_PLAYING;
462 mmd->new_vss_status_flags &= ~VSS_REPOS;
463 mmd->new_vss_status_flags |= VSS_NEXT;
469 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
472 return -E_COMMAND_SYNTAX;
474 if (!vss_paused() && !vss_stopped()) {
476 mmd->new_vss_status_flags &= ~VSS_PLAYING;
477 mmd->new_vss_status_flags &= ~VSS_NEXT;
484 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
487 return -E_COMMAND_SYNTAX;
490 mmd->new_vss_status_flags |= VSS_NEXT;
496 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
499 return -E_COMMAND_SYNTAX;
501 if (vss_playing() || vss_paused())
502 mmd->new_vss_status_flags |= VSS_NOMORE;
508 int com_ff(__a_unused int fd, int argc, char * const * argv)
511 int ret, backwards = 0;
516 return -E_COMMAND_SYNTAX;
517 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
518 return -E_COMMAND_SYNTAX;
519 if (ret > 1 && c == '-')
520 backwards = 1; /* jmp backwards */
522 ret = -E_NO_AUDIO_FILE;
523 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
525 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
527 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
529 promille += 1000 * i / mmd->afd.afhi.seconds_total;
532 if (promille > 1000) {
533 mmd->new_vss_status_flags |= VSS_NEXT;
536 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
537 mmd->new_vss_status_flags |= VSS_REPOS;
538 mmd->new_vss_status_flags &= ~VSS_NEXT;
547 int com_jmp(__a_unused int fd, int argc, char * const * argv)
553 return -E_COMMAND_SYNTAX;
554 if (sscanf(argv[1], "%lu", &i) <= 0)
555 return -E_COMMAND_SYNTAX;
557 ret = -E_NO_AUDIO_FILE;
558 if (!mmd->afd.afhi.chunks_total)
562 PARA_INFO_LOG("jumping to %lu%%\n", i);
563 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
564 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
565 mmd->chunks_sent, mmd->offset);
566 mmd->new_vss_status_flags |= VSS_REPOS;
567 mmd->new_vss_status_flags &= ~VSS_NEXT;
576 * check if perms are sufficient to exec a command having perms cmd_perms.
577 * Returns 0 if perms are sufficient, -E_PERM otherwise.
579 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
581 PARA_DEBUG_LOG("checking permissions\n");
582 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
586 * Parse first string from *cmd and lookup in table of valid commands.
587 * On error, NULL is returned.
589 static struct server_command *parse_cmd(const char *cmdstr)
594 sscanf(cmdstr, "%200s%n", buf, &n);
598 return get_cmd_ptr(buf, NULL);
601 static void init_rc4_keys(void)
605 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
606 rc4_buf[i] = para_random(256);
607 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
608 (unsigned char) rc4_buf[0],
609 (unsigned char) rc4_buf[RC4_KEY_LEN]);
610 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
611 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
614 static void rc4_recv(unsigned long len, const unsigned char *indata,
615 unsigned char *outdata, __a_unused void *private_data)
617 RC4(&rc4_recv_key, len, indata, outdata);
620 static void rc4_send(unsigned long len, const unsigned char *indata,
621 unsigned char *outdata, __a_unused void *private_data)
623 RC4(&rc4_send_key, len, indata, outdata);
626 static int read_command(int fd, char **result)
630 char *command = NULL;
636 ret = recv_buffer(fd, buf, sizeof(buf));
642 ret = -E_COMMAND_SYNTAX;
643 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
645 command = para_strcat(command, buf);
646 p = strstr(command, EOC_MSG);
652 ret = command? 1 : -E_COMMAND_SYNTAX;
663 * perform user authentication and execute a command
665 * \param fd The file descriptor to send output to
666 * \param peername Identifies the connecting peer.
668 * \return EXIT_SUCCESS or EXIT_FAILURE
670 * Whenever para_server accepts an incoming tcp connection on
671 * the port it listens on, it forks and the resulting child
672 * calls this function.
674 * An RSA-based challenge/response is used to authenticate
675 * the peer. It that authentication succeeds, a random RC4
676 * session key is generated and sent back to the peer,
677 * encrypted with its RSA public key. From this point on,
678 * all transfers are crypted with this session key.
680 * Next it is checked if the peer supplied a valid server command or a command
681 * for the audio file selector. If yes, and if the user has sufficient
682 * permissions to execute that command, the function calls the corresponding
683 * command handler which does argument checking and further processing.
685 * In order to cope with a DOS attacks, a timeout is set up
686 * which terminates the function if the connection was not
687 * authenticated when the timeout expires.
689 * \sa alarm(2), rc4(3), crypt.c, crypt.h
691 int handle_connect(int fd, const char *peername)
693 int ret, argc, use_rc4 = 0;
695 unsigned char crypt_buf[MAXLINE];
697 struct server_command *cmd = NULL;
698 long unsigned challenge_nr, chall_response;
700 char *p, *command = NULL;
703 signal(SIGCHLD, SIG_IGN);
704 signal(SIGINT, SIG_DFL);
705 signal(SIGTERM, SIG_DFL);
706 signal(SIGHUP, SIG_DFL);
708 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
709 ret = mark_fd_blocking(fd);
712 challenge_nr = random();
713 /* send Welcome message */
714 ret = send_va_buffer(fd, "This is para_server, version "
715 PACKAGE_VERSION ".\n" );
718 /* recv auth request line */
719 ret = recv_buffer(fd, buf, sizeof(buf));
728 if (strncmp(buf, "auth ", 5))
731 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
732 p = buf + 5; /* client version < 0.2.6 */
734 p = buf + 9; /* client version >= 0.2.6 */
737 PARA_DEBUG_LOG("received %s request for user %s\n",
738 use_rc4? "rc4" : "auth", p);
743 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
747 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
748 /* We can't use send_buffer here since buf may contain null bytes */
749 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
752 /* recv decrypted number */
753 ret = recv_buffer(fd, buf, sizeof(buf));
760 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
761 || chall_response != challenge_nr)
763 /* auth successful, send 'Proceed' message */
764 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
765 sprintf(buf, "%s", PROCEED_MSG);
768 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
769 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
772 numbytes = ret + strlen(PROCEED_MSG) + 1;
774 numbytes = strlen(buf);
775 ret = send_bin_buffer(fd, buf, numbytes);
779 enable_crypt(fd, rc4_recv, rc4_send, NULL);
780 ret = read_command(fd, &command);
781 if (ret == -E_COMMAND_SYNTAX)
786 cmd = parse_cmd(command);
789 /* valid command, check permissions */
790 ret = check_perms(u->perms, cmd);
793 /* valid command and sufficient perms */
795 argc = split_args(command, &argv, "\n");
799 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
801 ret = cmd->handler(fd, argc, argv);
807 send_va_buffer(fd, "%s\n", para_strerror(-ret));
809 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
815 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
817 mmd->active_connections--;