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' : '_';
98 static char *get_status(struct misc_meta_data *nmmd)
100 char *ret, mtime[30] = "";
101 char *status, *flags; /* vss status info */
102 char *ut = uptime_str();
103 long offset = (nmmd->offset + 500) / 1000;
107 /* report real status */
108 status = vss_status_tohuman(nmmd->vss_status_flags);
109 flags = vss_get_status_flags(nmmd->vss_status_flags);
110 if (nmmd->size) { /* parent currently has an audio file open */
111 localtime_r(&nmmd->mtime, &mtime_tm);
112 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
114 gettimeofday(&now, NULL);
116 "%s: %zu\n" /* file size */
117 "%s: %s\n" /* mtime */
118 "%s: %s\n" /* status */
119 "%s: %s\n" /* status flags */
120 "%s: %li\n" /* offset */
121 "%s: %s\n" /* afs mode */
122 "%s: %s\n" /* server uptime */
123 "%s: %lu.%lu\n" /* stream start */
124 "%s: %lu.%lu\n" /* current server time */
125 "%s\n", /* afs status info */
126 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
127 status_item_list[SI_MTIME], mtime,
128 status_item_list[SI_STATUS], status,
129 status_item_list[SI_STATUS_FLAGS], flags,
131 status_item_list[SI_OFFSET], offset,
132 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
134 status_item_list[SI_UPTIME], ut,
135 status_item_list[SI_STREAM_START],
136 (long unsigned)nmmd->stream_start.tv_sec,
137 (long unsigned)nmmd->stream_start.tv_usec,
138 status_item_list[SI_CURRENT_TIME],
139 (long unsigned)now.tv_sec,
140 (long unsigned)now.tv_usec,
142 nmmd->afd.verbose_ls_output
151 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
154 /* this has to match sender.h */
155 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
157 scd->sender_num = -1;
159 return -E_COMMAND_SYNTAX;
160 for (i = 0; senders[i].name; i++)
161 if (!strcmp(senders[i].name, argv[1]))
163 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
164 if (!senders[i].name)
165 return -E_COMMAND_SYNTAX;
167 for (i = 0; subcmds[i]; i++)
168 if (!strcmp(subcmds[i], argv[2]))
171 return -E_COMMAND_SYNTAX;
174 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
176 return -E_SENDER_CMD;
179 switch (scd->cmd_num) {
183 return -E_COMMAND_SYNTAX;
187 if (argc != 4 && argc != 5)
188 return -E_COMMAND_SYNTAX;
189 if (!inet_pton(AF_INET, argv[3], &scd->addr))
190 return -E_COMMAND_SYNTAX;
193 scd->netmask = atoi(argv[4]);
194 if (scd->netmask < 0 || scd->netmask > 32)
195 return -E_COMMAND_SYNTAX;
200 if (argc != 4 && argc != 5)
201 return -E_COMMAND_SYNTAX;
202 if (!inet_pton(AF_INET, argv[3], &scd->addr))
203 return -E_COMMAND_SYNTAX;
206 scd->port = atoi(argv[4]);
207 if (scd->port < 0 || scd->port > 65535)
208 return -E_COMMAND_SYNTAX;
212 return -E_COMMAND_SYNTAX;
217 int com_sender(int fd, int argc, char * const * argv)
220 struct sender_command_data scd;
224 for (i = 0; senders[i].name; i++) {
225 char *tmp = make_message("%s%s\n",
226 msg? msg : "", senders[i].name);
230 ret = send_buffer(fd, msg);
234 ret = check_sender_args(argc, argv, &scd);
237 if (scd.sender_num < 0)
239 msg = senders[scd.sender_num].help();
240 send_buffer(fd, msg);
244 for (i = 0; i < 10; i++) {
246 if (mmd->sender_cmd_data.cmd_num >= 0) {
251 mmd->sender_cmd_data = scd;
255 return (i < 10)? 1 : -E_LOCK;
259 int com_si(int fd, int argc, __a_unused char * const * argv)
263 char *sender_info = NULL, *sender_list = NULL;
266 return -E_COMMAND_SYNTAX;
268 for (i = 0; senders[i].name; i++) {
269 char *info = senders[i].info();
270 sender_info = para_strcat(sender_info, info);
272 sender_list = para_strcat(sender_list, senders[i].name);
273 sender_list = para_strcat(sender_list, " ");
276 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
278 "connections (active/accepted/total): %u/%u/%u\n"
279 "current loglevel: %i\n"
280 "supported audio formats: %s\n"
281 "supported senders: %s\n"
285 mmd->active_connections,
289 supported_audio_formats(),
301 int com_version(int fd, int argc, __a_unused char * const * argv)
304 return -E_COMMAND_SYNTAX;
305 return send_buffer(fd, VERSION_TEXT("server")
306 "built: " BUILD_DATE "\n"
307 SYSTEM ", " CC_VERSION "\n"
312 int com_stat(int fd, int argc, char * const * argv)
314 int ret, num = 0;/* status will be printed that many
315 * times. num <= 0 means: print forever
317 struct misc_meta_data tmp, *nmmd = &tmp;
320 signal(SIGUSR1, dummy);
327 s = get_status(nmmd);
328 ret = send_buffer(fd, s);
337 return -E_SERVER_CRASH;
343 static int send_list_of_commands(int fd, struct server_command *cmd,
348 for (i = 1; cmd->name; cmd++, i++) {
349 char *perms = cmd_perms_itohuman(cmd->perms);
350 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
361 /* returns string that must be freed by the caller */
362 static struct server_command *get_cmd_ptr(const char *name, char **handler)
364 struct server_command *cmd;
366 for (cmd = server_cmds; cmd->name; cmd++)
367 if (!strcmp(cmd->name, name)) {
369 *handler = para_strdup("server"); /* server commands */
372 /* not found, look for commands supported by afs */
373 for (cmd = afs_cmds; cmd->name; cmd++)
374 if (!strcmp(cmd->name, name)) {
376 *handler = para_strdup("afs");
383 int com_help(int fd, int argc, char * const * argv)
385 struct server_command *cmd;
386 char *perms, *handler;
390 /* no argument given, print list of commands */
391 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
393 return send_list_of_commands(fd, afs_cmds, "afs");
395 /* argument given for help */
396 cmd = get_cmd_ptr(argv[1], &handler);
401 perms = cmd_perms_itohuman(cmd->perms);
402 ret = send_va_buffer(fd,
421 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
424 return -E_COMMAND_SYNTAX;
425 kill(getppid(), SIGHUP);
430 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
433 return -E_COMMAND_SYNTAX;
434 kill(getppid(), SIGTERM);
438 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
441 return -E_COMMAND_SYNTAX;
443 mmd->new_vss_status_flags |= VSS_PLAYING;
444 mmd->new_vss_status_flags &= ~VSS_NOMORE;
451 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
454 return -E_COMMAND_SYNTAX;
456 mmd->new_vss_status_flags &= ~VSS_PLAYING;
457 mmd->new_vss_status_flags &= ~VSS_REPOS;
458 mmd->new_vss_status_flags |= VSS_NEXT;
464 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
467 return -E_COMMAND_SYNTAX;
471 mmd->new_vss_status_flags &= ~VSS_PLAYING;
472 mmd->new_vss_status_flags &= ~VSS_NEXT;
478 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
481 return -E_COMMAND_SYNTAX;
484 mmd->new_vss_status_flags |= VSS_NEXT;
490 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
493 return -E_COMMAND_SYNTAX;
495 if (vss_playing() || vss_paused())
496 mmd->new_vss_status_flags |= VSS_NOMORE;
502 int com_ff(__a_unused int fd, int argc, char * const * argv)
505 int ret, backwards = 0;
510 return -E_COMMAND_SYNTAX;
511 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
512 return -E_COMMAND_SYNTAX;
513 if (ret > 1 && c == '-')
514 backwards = 1; /* jmp backwards */
516 ret = -E_NO_AUDIO_FILE;
517 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
519 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
521 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
523 promille += 1000 * i / mmd->afd.afhi.seconds_total;
526 if (promille > 1000) {
527 mmd->new_vss_status_flags |= VSS_NEXT;
530 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
531 mmd->new_vss_status_flags |= VSS_REPOS;
532 mmd->new_vss_status_flags &= ~VSS_NEXT;
541 int com_jmp(__a_unused int fd, int argc, char * const * argv)
547 return -E_COMMAND_SYNTAX;
548 if (sscanf(argv[1], "%lu", &i) <= 0)
549 return -E_COMMAND_SYNTAX;
551 ret = -E_NO_AUDIO_FILE;
552 if (!mmd->afd.afhi.chunks_total)
556 PARA_INFO_LOG("jumping to %lu%%\n", i);
557 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
558 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
559 mmd->chunks_sent, mmd->offset);
560 mmd->new_vss_status_flags |= VSS_REPOS;
561 mmd->new_vss_status_flags &= ~VSS_NEXT;
570 * check if perms are sufficient to exec a command having perms cmd_perms.
571 * Returns 0 if perms are sufficient, -E_PERM otherwise.
573 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
575 PARA_DEBUG_LOG("%s", "checking permissions\n");
576 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
580 * Parse first string from *cmd and lookup in table of valid commands.
581 * On error, NULL is returned.
583 static struct server_command *parse_cmd(const char *cmdstr)
588 sscanf(cmdstr, "%200s%n", buf, &n);
592 return get_cmd_ptr(buf, NULL);
595 static void init_rc4_keys(void)
599 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
600 rc4_buf[i] = para_random(256);
601 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
602 (unsigned char) rc4_buf[0],
603 (unsigned char) rc4_buf[RC4_KEY_LEN]);
604 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
605 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
608 static void rc4_recv(unsigned long len, const unsigned char *indata,
609 unsigned char *outdata, __a_unused void *private_data)
611 RC4(&rc4_recv_key, len, indata, outdata);
614 static void rc4_send(unsigned long len, const unsigned char *indata,
615 unsigned char *outdata, __a_unused void *private_data)
617 RC4(&rc4_send_key, len, indata, outdata);
620 static int read_command(int fd, char **result)
624 char *command = NULL;
630 ret = recv_buffer(fd, buf, sizeof(buf));
636 ret = -E_COMMAND_SYNTAX;
637 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
639 command = para_strcat(command, buf);
640 p = strstr(command, EOC_MSG);
646 ret = command? 1 : -E_COMMAND_SYNTAX;
657 * perform user authentication and execute a command
659 * \param fd the file descriptor to send output to
660 * \param addr socket address info of peer
662 * \return EXIT_SUCCESS or EXIT_FAILURE
664 * Whenever para_server accepts an incoming tcp connection on
665 * the port it listens on, it forks and the resulting child
666 * calls this function.
668 * An RSA-based challenge/response is used to authenticate
669 * the peer. It that authentication succeeds, a random RC4
670 * session key is generated and sent back to the peer,
671 * encrypted with its RSA public key. From this point on,
672 * all transfers are crypted with this session key.
674 * Next it is checked if the peer supplied a valid server command or a command
675 * for the audio file selector. If yes, and if the user has sufficient
676 * permissions to execute that command, the function calls the corresponding
677 * command handler which does argument checking and further processing.
679 * In order to cope with a DOS attacks, a timeout is set up
680 * which terminates the function if the connection was not
681 * authenticated when the timeout expires.
683 * \sa alarm(2), rc4(3), crypt.c, crypt.h
685 int handle_connect(int fd, struct sockaddr_in *addr)
687 int ret, argc, use_rc4 = 0;
689 unsigned char crypt_buf[MAXLINE];
691 struct server_command *cmd = NULL;
692 long unsigned challenge_nr, chall_response;
694 char *p, *command = NULL;
697 signal(SIGCHLD, SIG_IGN);
698 signal(SIGINT, SIG_DFL);
699 signal(SIGTERM, SIG_DFL);
700 signal(SIGHUP, SIG_DFL);
701 signal(SIGUSR1, SIG_IGN);
703 challenge_nr = random();
704 /* send Welcome message */
705 ret = send_va_buffer(fd, "This is para_server, version "
706 PACKAGE_VERSION ".\n" );
709 /* recv auth request line */
710 ret = recv_buffer(fd, buf, sizeof(buf));
719 if (strncmp(buf, "auth ", 5))
722 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
723 p = buf + 5; /* client version < 0.2.6 */
725 p = buf + 9; /* client version >= 0.2.6 */
728 PARA_DEBUG_LOG("received %s request for user %s\n",
729 use_rc4? "rc4" : "auth", p);
734 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
738 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
739 /* We can't use send_buffer here since buf may contain null bytes */
740 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
743 /* recv decrypted number */
744 ret = recv_buffer(fd, buf, sizeof(buf));
751 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
752 || chall_response != challenge_nr)
754 /* auth successful, send 'Proceed' message */
755 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
756 sprintf(buf, "%s", PROCEED_MSG);
759 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
760 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
763 numbytes = ret + strlen(PROCEED_MSG) + 1;
765 numbytes = strlen(buf);
766 ret = send_bin_buffer(fd, buf, numbytes);
770 enable_crypt(fd, rc4_recv, rc4_send, NULL);
771 ret = read_command(fd, &command);
775 cmd = parse_cmd(command);
778 /* valid command, check permissions */
779 ret = check_perms(u->perms, cmd);
782 /* valid command and sufficient perms */
784 argc = split_args(command, &argv, "\n");
788 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
789 inet_ntoa(addr->sin_addr));
790 ret = cmd->handler(fd, argc, argv);
796 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
797 if (ret != -E_SEND && ret != -E_RECV)
798 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
804 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
806 mmd->active_connections--;