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 *basename, *dirname, *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 basename = para_basename(nmmd->afd.path);
111 dirname = para_dirname(nmmd->afd.path);
113 localtime_r(&nmmd->mtime, &mtime_tm);
114 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
116 gettimeofday(&now, NULL);
118 "%s:%zu\n" "%s:%s\n" "%s:%lu\n"
119 "%s:%s\n" "%s:%s\n" "%s:%s\n"
120 "%s:%li\n" "%s:%s\n" "%s"
121 "%s:%s\n" "%s:%lu.%lu\n" "%s:%lu.%lu\n"
123 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
124 status_item_list[SI_MTIME], mtime,
125 status_item_list[SI_LENGTH], nmmd->afd.afhi.seconds_total,
127 status_item_list[SI_BASENAME], basename ? basename : "(none)",
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,
133 nmmd->afd.afhi.info_string,
135 status_item_list[SI_UPTIME], ut,
136 status_item_list[SI_STREAM_START],
137 (long unsigned)nmmd->stream_start.tv_sec,
138 (long unsigned)nmmd->stream_start.tv_usec,
139 status_item_list[SI_CURRENT_TIME],
140 (long unsigned)now.tv_sec,
141 (long unsigned)now.tv_usec,
143 status_item_list[SI_DIRECTORY], dirname? dirname : "(none)",
144 nmmd->afd.afs_status_info
155 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
158 /* this has to match sender.h */
159 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
161 scd->sender_num = -1;
163 return -E_COMMAND_SYNTAX;
164 for (i = 0; senders[i].name; i++)
165 if (!strcmp(senders[i].name, argv[1]))
167 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
168 if (!senders[i].name)
169 return -E_COMMAND_SYNTAX;
171 for (i = 0; subcmds[i]; i++)
172 if (!strcmp(subcmds[i], argv[2]))
175 return -E_COMMAND_SYNTAX;
178 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
180 return -E_SENDER_CMD;
183 switch (scd->cmd_num) {
187 return -E_COMMAND_SYNTAX;
191 if (argc != 4 && argc != 5)
192 return -E_COMMAND_SYNTAX;
193 if (!inet_pton(AF_INET, argv[3], &scd->addr))
194 return -E_COMMAND_SYNTAX;
197 scd->netmask = atoi(argv[4]);
198 if (scd->netmask < 0 || scd->netmask > 32)
199 return -E_COMMAND_SYNTAX;
204 if (argc != 4 && argc != 5)
205 return -E_COMMAND_SYNTAX;
206 if (!inet_pton(AF_INET, argv[3], &scd->addr))
207 return -E_COMMAND_SYNTAX;
210 scd->port = atoi(argv[4]);
211 if (scd->port < 0 || scd->port > 65535)
212 return -E_COMMAND_SYNTAX;
216 return -E_COMMAND_SYNTAX;
221 int com_sender(int fd, int argc, char * const * argv)
224 struct sender_command_data scd;
228 for (i = 0; senders[i].name; i++) {
229 char *tmp = make_message("%s%s\n",
230 msg? msg : "", senders[i].name);
234 ret = send_buffer(fd, msg);
238 ret = check_sender_args(argc, argv, &scd);
241 if (scd.sender_num < 0)
243 msg = senders[scd.sender_num].help();
244 send_buffer(fd, msg);
248 for (i = 0; i < 10; i++) {
250 if (mmd->sender_cmd_data.cmd_num >= 0) {
255 mmd->sender_cmd_data = scd;
259 return (i < 10)? 1 : -E_LOCK;
263 int com_si(int fd, int argc, __a_unused char * const * argv)
267 char *sender_info = NULL, *sender_list = NULL;
270 return -E_COMMAND_SYNTAX;
272 for (i = 0; senders[i].name; i++) {
273 char *info = senders[i].info();
274 sender_info = para_strcat(sender_info, info);
276 sender_list = para_strcat(sender_list, senders[i].name);
277 sender_list = para_strcat(sender_list, " ");
280 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
282 "connections (active/accepted/total): %u/%u/%u\n"
283 "current loglevel: %i\n"
284 "supported audio formats: %s\n"
285 "supported senders: %s\n"
289 mmd->active_connections,
293 supported_audio_formats(),
305 int com_version(int fd, int argc, __a_unused char * const * argv)
308 return -E_COMMAND_SYNTAX;
309 return send_buffer(fd, VERSION_TEXT("server")
310 "built: " BUILD_DATE "\n"
311 SYSTEM ", " CC_VERSION "\n"
316 int com_stat(int fd, int argc, char * const * argv)
318 int ret, num = 0;/* status will be printed that many
319 * times. num <= 0 means: print forever
321 struct misc_meta_data tmp, *nmmd = &tmp;
324 signal(SIGUSR1, dummy);
331 s = get_status(nmmd);
332 ret = send_buffer(fd, s);
341 return -E_SERVER_CRASH;
347 static int send_list_of_commands(int fd, struct server_command *cmd,
352 for (i = 1; cmd->name; cmd++, i++) {
353 char *perms = cmd_perms_itohuman(cmd->perms);
354 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
365 /* returns string that must be freed by the caller */
366 static struct server_command *get_cmd_ptr(const char *name, char **handler)
368 struct server_command *cmd;
370 for (cmd = server_cmds; cmd->name; cmd++)
371 if (!strcmp(cmd->name, name)) {
373 *handler = para_strdup("server"); /* server commands */
376 /* not found, look for commands supported by afs */
377 for (cmd = afs_cmds; cmd->name; cmd++)
378 if (!strcmp(cmd->name, name)) {
380 *handler = para_strdup("afs");
387 int com_help(int fd, int argc, char * const * argv)
389 struct server_command *cmd;
390 char *perms, *handler;
394 /* no argument given, print list of commands */
395 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
397 return send_list_of_commands(fd, afs_cmds, "afs");
399 /* argument given for help */
400 cmd = get_cmd_ptr(argv[1], &handler);
405 perms = cmd_perms_itohuman(cmd->perms);
406 ret = send_va_buffer(fd,
425 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
428 return -E_COMMAND_SYNTAX;
429 kill(getppid(), SIGHUP);
434 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
437 return -E_COMMAND_SYNTAX;
438 kill(getppid(), SIGTERM);
442 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
445 return -E_COMMAND_SYNTAX;
447 mmd->new_vss_status_flags |= VSS_PLAYING;
448 mmd->new_vss_status_flags &= ~VSS_NOMORE;
455 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
458 return -E_COMMAND_SYNTAX;
460 mmd->new_vss_status_flags &= ~VSS_PLAYING;
461 mmd->new_vss_status_flags &= ~VSS_REPOS;
462 mmd->new_vss_status_flags |= VSS_NEXT;
468 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
471 return -E_COMMAND_SYNTAX;
475 mmd->new_vss_status_flags &= ~VSS_PLAYING;
476 mmd->new_vss_status_flags &= ~VSS_NEXT;
482 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
485 return -E_COMMAND_SYNTAX;
488 mmd->new_vss_status_flags |= VSS_NEXT;
494 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
497 return -E_COMMAND_SYNTAX;
499 if (vss_playing() || vss_paused())
500 mmd->new_vss_status_flags |= VSS_NOMORE;
506 int com_ff(__a_unused int fd, int argc, char * const * argv)
509 int ret, backwards = 0;
514 return -E_COMMAND_SYNTAX;
515 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
516 return -E_COMMAND_SYNTAX;
517 if (ret > 1 && c == '-')
518 backwards = 1; /* jmp backwards */
520 ret = -E_NO_AUDIO_FILE;
521 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
523 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
525 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
527 promille += 1000 * i / mmd->afd.afhi.seconds_total;
530 if (promille > 1000) {
531 mmd->new_vss_status_flags |= VSS_NEXT;
534 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
535 mmd->new_vss_status_flags |= VSS_REPOS;
536 mmd->new_vss_status_flags &= ~VSS_NEXT;
545 int com_jmp(__a_unused int fd, int argc, char * const * argv)
551 return -E_COMMAND_SYNTAX;
552 if (sscanf(argv[1], "%lu", &i) <= 0)
553 return -E_COMMAND_SYNTAX;
555 ret = -E_NO_AUDIO_FILE;
556 if (!mmd->afd.afhi.chunks_total)
560 PARA_INFO_LOG("jumping to %lu%%\n", i);
561 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
562 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
563 mmd->chunks_sent, mmd->offset);
564 mmd->new_vss_status_flags |= VSS_REPOS;
565 mmd->new_vss_status_flags &= ~VSS_NEXT;
574 * check if perms are sufficient to exec a command having perms cmd_perms.
575 * Returns 0 if perms are sufficient, -E_PERM otherwise.
577 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
579 PARA_DEBUG_LOG("%s", "checking permissions\n");
580 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
584 * Parse first string from *cmd and lookup in table of valid commands.
585 * On error, NULL is returned.
587 static struct server_command *parse_cmd(const char *cmdstr)
592 sscanf(cmdstr, "%200s%n", buf, &n);
596 return get_cmd_ptr(buf, NULL);
599 static void init_rc4_keys(void)
603 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
604 rc4_buf[i] = para_random(256);
605 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
606 (unsigned char) rc4_buf[0],
607 (unsigned char) rc4_buf[RC4_KEY_LEN]);
608 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
609 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
612 static void rc4_recv(unsigned long len, const unsigned char *indata,
613 unsigned char *outdata, __a_unused void *private_data)
615 RC4(&rc4_recv_key, len, indata, outdata);
618 static void rc4_send(unsigned long len, const unsigned char *indata,
619 unsigned char *outdata, __a_unused void *private_data)
621 RC4(&rc4_send_key, len, indata, outdata);
624 static int read_command(int fd, char **result)
628 char *command = NULL;
634 ret = recv_buffer(fd, buf, sizeof(buf));
640 ret = -E_COMMAND_SYNTAX;
641 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
643 command = para_strcat(command, buf);
644 p = strstr(command, EOC_MSG);
650 ret = command? 1 : -E_COMMAND_SYNTAX;
661 * perform user authentication and execute a command
663 * \param fd the file descriptor to send output to
664 * \param addr socket address info of peer
666 * \return EXIT_SUCCESS or EXIT_FAILURE
668 * Whenever para_server accepts an incoming tcp connection on
669 * the port it listens on, it forks and the resulting child
670 * calls this function.
672 * An RSA-based challenge/response is used to authenticate
673 * the peer. It that authentication succeeds, a random RC4
674 * session key is generated and sent back to the peer,
675 * encrypted with its RSA public key. From this point on,
676 * all transfers are crypted with this session key.
678 * Next it is checked if the peer supplied a valid server command or a command
679 * for the audio file selector. If yes, and if the user has sufficient
680 * permissions to execute that command, the function calls the corresponding
681 * command handler which does argument checking and further processing.
683 * In order to cope with a DOS attacks, a timeout is set up
684 * which terminates the function if the connection was not
685 * authenticated when the timeout expires.
687 * \sa alarm(2), rc4(3), crypt.c, crypt.h
689 int handle_connect(int fd, struct sockaddr_in *addr)
691 int ret, argc, use_rc4 = 0;
693 unsigned char crypt_buf[MAXLINE];
695 struct server_command *cmd = NULL;
696 long unsigned challenge_nr, chall_response;
698 char *p, *command = NULL;
701 signal(SIGCHLD, SIG_IGN);
702 signal(SIGINT, SIG_DFL);
703 signal(SIGTERM, SIG_DFL);
704 signal(SIGHUP, SIG_DFL);
705 signal(SIGUSR1, SIG_IGN);
707 challenge_nr = random();
708 /* send Welcome message */
709 ret = send_va_buffer(fd, "This is para_server, version "
710 PACKAGE_VERSION ".\n" );
713 /* recv auth request line */
714 ret = recv_buffer(fd, buf, sizeof(buf));
723 if (strncmp(buf, "auth ", 5))
726 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
727 p = buf + 5; /* client version < 0.2.6 */
729 p = buf + 9; /* client version >= 0.2.6 */
732 PARA_DEBUG_LOG("received %s request for user %s\n",
733 use_rc4? "rc4" : "auth", p);
738 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
742 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
743 /* We can't use send_buffer here since buf may contain null bytes */
744 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
747 /* recv decrypted number */
748 ret = recv_buffer(fd, buf, sizeof(buf));
755 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
756 || chall_response != challenge_nr)
758 /* auth successful, send 'Proceed' message */
759 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
760 sprintf(buf, "%s", PROCEED_MSG);
763 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
764 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
767 numbytes = ret + strlen(PROCEED_MSG) + 1;
769 numbytes = strlen(buf);
770 ret = send_bin_buffer(fd, buf, numbytes);
774 enable_crypt(fd, rc4_recv, rc4_send, NULL);
775 ret = read_command(fd, &command);
779 cmd = parse_cmd(command);
782 /* valid command, check permissions */
783 ret = check_perms(u->perms, cmd);
786 /* valid command and sufficient perms */
788 argc = split_args(command, &argv, "\n");
792 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
793 inet_ntoa(addr->sin_addr));
794 ret = cmd->handler(fd, argc, argv);
800 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
801 if (ret != -E_SEND && ret != -E_RECV)
802 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
808 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
810 mmd->active_connections--;