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 *bar, *ret, mtime[30] = "";
101 char *status, *flags; /* vss status info */
102 char *ut = uptime_str();
103 long offset = (nmmd->offset + 500) / 1000;
107 if (nmmd->audio_format >= 0) {
108 localtime_r(&nmmd->mtime, &mtime_tm);
109 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
111 /* report real status */
112 status = vss_status_tohuman(nmmd->vss_status_flags);
113 flags = vss_get_status_flags(nmmd->vss_status_flags);
114 bar = para_basename(nmmd->filename);
115 gettimeofday(&now, NULL);
117 "%s:%zu\n" "%s:%s\n" "%s:%lu\n" "%s:%u\n"
118 "%s:%s\n" "%s:%s\n" "%s:%s\n" "%s:%s\n"
119 "%s:%li\n" "%s:%s\n" "%s:%s\n" "%s"
120 "%s:%s\n" "%s:%lu.%lu\n" "%s:%lu.%lu\n",
121 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
122 status_item_list[SI_MTIME], mtime,
123 status_item_list[SI_LENGTH], nmmd->afi.seconds_total,
124 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
126 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
127 status_item_list[SI_STATUS], status,
128 status_item_list[SI_STATUS_FLAGS], flags,
129 status_item_list[SI_SELECTOR], "FIXME",
131 status_item_list[SI_OFFSET], offset,
132 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
133 status_item_list[SI_AFS_MODE], mmd->afs_mode_string,
134 nmmd->afi.info_string,
136 status_item_list[SI_UPTIME], ut,
137 status_item_list[SI_STREAM_START],
138 (long unsigned)nmmd->stream_start.tv_sec,
139 (long unsigned)nmmd->stream_start.tv_usec,
140 status_item_list[SI_CURRENT_TIME],
141 (long unsigned)now.tv_sec,
142 (long unsigned)now.tv_usec
152 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
155 /* this has to match sender.h */
156 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
158 scd->sender_num = -1;
160 return -E_COMMAND_SYNTAX;
161 for (i = 0; senders[i].name; i++)
162 if (!strcmp(senders[i].name, argv[1]))
164 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
165 if (!senders[i].name)
166 return -E_COMMAND_SYNTAX;
168 for (i = 0; subcmds[i]; i++)
169 if (!strcmp(subcmds[i], argv[2]))
172 return -E_COMMAND_SYNTAX;
175 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
177 return -E_SENDER_CMD;
180 switch (scd->cmd_num) {
184 return -E_COMMAND_SYNTAX;
188 if (argc != 4 && argc != 5)
189 return -E_COMMAND_SYNTAX;
190 if (!inet_pton(AF_INET, argv[3], &scd->addr))
191 return -E_COMMAND_SYNTAX;
194 scd->netmask = atoi(argv[4]);
195 if (scd->netmask < 0 || scd->netmask > 32)
196 return -E_COMMAND_SYNTAX;
201 if (argc != 4 && argc != 5)
202 return -E_COMMAND_SYNTAX;
203 if (!inet_pton(AF_INET, argv[3], &scd->addr))
204 return -E_COMMAND_SYNTAX;
207 scd->port = atoi(argv[4]);
208 if (scd->port < 0 || scd->port > 65535)
209 return -E_COMMAND_SYNTAX;
213 return -E_COMMAND_SYNTAX;
218 int com_sender(int fd, int argc, char * const * argv)
221 struct sender_command_data scd;
225 for (i = 0; senders[i].name; i++) {
226 char *tmp = make_message("%s%s\n",
227 msg? msg : "", senders[i].name);
231 ret = send_buffer(fd, msg);
235 ret = check_sender_args(argc, argv, &scd);
238 if (scd.sender_num < 0)
240 msg = senders[scd.sender_num].help();
241 send_buffer(fd, msg);
245 for (i = 0; i < 10; i++) {
247 if (mmd->sender_cmd_data.cmd_num >= 0) {
252 mmd->sender_cmd_data = scd;
256 return (i < 10)? 1 : -E_LOCK;
260 int com_si(int fd, int argc, __a_unused char * const * argv)
264 char *sender_info = NULL, *sender_list = NULL;
267 return -E_COMMAND_SYNTAX;
269 for (i = 0; senders[i].name; i++) {
270 char *info = senders[i].info();
271 sender_info = para_strcat(sender_info, info);
273 sender_list = para_strcat(sender_list, senders[i].name);
274 sender_list = para_strcat(sender_list, " ");
277 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
279 "connections (active/accepted/total): %u/%u/%u\n"
280 "current loglevel: %i\n"
281 "supported audio formats: %s\n"
282 "supported senders: %s\n"
286 mmd->active_connections,
290 supported_audio_formats(),
302 int com_version(int fd, int argc, __a_unused char * const * argv)
305 return -E_COMMAND_SYNTAX;
306 return send_buffer(fd, VERSION_TEXT("server")
307 "built: " BUILD_DATE "\n"
308 SYSTEM ", " CC_VERSION "\n"
313 int com_stat(int fd, int argc, char * const * argv)
315 int ret, num = 0;/* status will be printed that many
316 * times. num <= 0 means: print forever
318 struct misc_meta_data tmp, *nmmd = &tmp;
321 signal(SIGUSR1, dummy);
328 s = get_status(nmmd);
329 ret = send_buffer(fd, s);
338 return -E_SERVER_CRASH;
344 static int send_list_of_commands(int fd, struct server_command *cmd,
349 for (i = 1; cmd->name; cmd++, i++) {
350 char *perms = cmd_perms_itohuman(cmd->perms);
351 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
362 /* returns string that must be freed by the caller */
363 static struct server_command *get_cmd_ptr(const char *name, char **handler)
365 struct server_command *cmd;
367 for (cmd = server_cmds; cmd->name; cmd++)
368 if (!strcmp(cmd->name, name)) {
370 *handler = para_strdup("para_server"); /* server commands */
373 /* not found, look for commands supported by afs */
374 for (cmd = afs_cmds; cmd->name; cmd++)
375 if (!strcmp(cmd->name, name))
381 int com_help(int fd, int argc, char * const * argv)
383 struct server_command *cmd;
384 char *perms, *handler;
388 /* no argument given, print list of commands */
389 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
391 return send_list_of_commands(fd, afs_cmds, "afs");
393 /* argument given for help */
394 cmd = get_cmd_ptr(argv[1], &handler);
399 perms = cmd_perms_itohuman(cmd->perms);
400 ret = send_va_buffer(fd,
419 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
422 return -E_COMMAND_SYNTAX;
423 kill(getppid(), SIGHUP);
428 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
431 return -E_COMMAND_SYNTAX;
432 kill(getppid(), SIGTERM);
436 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
439 return -E_COMMAND_SYNTAX;
441 mmd->new_vss_status_flags |= VSS_PLAYING;
442 mmd->new_vss_status_flags &= ~VSS_NOMORE;
449 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
452 return -E_COMMAND_SYNTAX;
454 mmd->new_vss_status_flags &= ~VSS_PLAYING;
455 mmd->new_vss_status_flags &= ~VSS_REPOS;
456 mmd->new_vss_status_flags |= VSS_NEXT;
462 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
465 return -E_COMMAND_SYNTAX;
469 mmd->new_vss_status_flags &= ~VSS_PLAYING;
470 mmd->new_vss_status_flags &= ~VSS_NEXT;
476 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
479 return -E_COMMAND_SYNTAX;
482 mmd->new_vss_status_flags |= VSS_NEXT;
488 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
491 return -E_COMMAND_SYNTAX;
493 if (vss_playing() || vss_paused())
494 mmd->new_vss_status_flags |= VSS_NOMORE;
500 int com_ff(__a_unused int fd, int argc, char * const * argv)
503 int ret, backwards = 0;
508 return -E_COMMAND_SYNTAX;
509 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
510 return -E_COMMAND_SYNTAX;
511 if (ret > 1 && c == '-')
512 backwards = 1; /* jmp backwards */
514 ret = -E_NO_AUDIO_FILE;
515 if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
517 promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
519 promille -= 1000 * i / mmd->afi.seconds_total;
521 promille += 1000 * i / mmd->afi.seconds_total;
524 if (promille > 1000) {
525 mmd->new_vss_status_flags |= VSS_NEXT;
528 mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
529 mmd->new_vss_status_flags |= VSS_REPOS;
530 mmd->new_vss_status_flags &= ~VSS_NEXT;
539 int com_jmp(__a_unused int fd, int argc, char * const * argv)
545 return -E_COMMAND_SYNTAX;
546 if (sscanf(argv[1], "%lu", &i) <= 0)
547 return -E_COMMAND_SYNTAX;
549 ret = -E_NO_AUDIO_FILE;
550 if (!mmd->afi.chunks_total)
554 PARA_INFO_LOG("jumping to %lu%%\n", i);
555 mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
556 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
557 mmd->chunks_sent, mmd->offset);
558 mmd->new_vss_status_flags |= VSS_REPOS;
559 mmd->new_vss_status_flags &= ~VSS_NEXT;
568 * check if perms are sufficient to exec a command having perms cmd_perms.
569 * Returns 0 if perms are sufficient, -E_PERM otherwise.
571 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
573 PARA_DEBUG_LOG("%s", "checking permissions\n");
574 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
578 * Parse first string from *cmd and lookup in table of valid commands.
579 * On error, NULL is returned.
581 static struct server_command *parse_cmd(const char *cmdstr)
586 sscanf(cmdstr, "%200s%n", buf, &n);
590 return get_cmd_ptr(buf, NULL);
593 static long int para_rand(long unsigned max)
595 return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
598 static void init_rc4_keys(void)
602 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
603 rc4_buf[i] = para_rand(256);
604 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
605 (unsigned char) rc4_buf[0],
606 (unsigned char) rc4_buf[RC4_KEY_LEN]);
607 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
608 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
611 static void rc4_recv(unsigned long len, const unsigned char *indata,
612 unsigned char *outdata, __a_unused void *private_data)
614 RC4(&rc4_recv_key, len, indata, outdata);
617 static void rc4_send(unsigned long len, const unsigned char *indata,
618 unsigned char *outdata, __a_unused void *private_data)
620 RC4(&rc4_send_key, len, indata, outdata);
623 static int read_command(int fd, char **result)
627 char *command = NULL;
633 ret = recv_buffer(fd, buf, sizeof(buf));
639 ret = -E_COMMAND_SYNTAX;
640 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
642 command = para_strcat(command, buf);
643 p = strstr(command, EOC_MSG);
649 ret = command? 1 : -E_COMMAND_SYNTAX;
660 * perform user authentication and execute a command
662 * \param fd the file descriptor to send output to
663 * \param addr socket address info of peer
665 * \return EXIT_SUCCESS or EXIT_FAILURE
667 * Whenever para_server accepts an incoming tcp connection on
668 * the port it listens on, it forks and the resulting child
669 * calls this function.
671 * An RSA-based challenge/response is used to authenticate
672 * the peer. It that authentication succeeds, a random RC4
673 * session key is generated and sent back to the peer,
674 * encrypted with its RSA public key. From this point on,
675 * all transfers are crypted with this session key.
677 * Next it is checked if the peer supplied a valid server command or a command
678 * for the audio file selector. If yes, and if the user has sufficient
679 * permissions to execute that command, the function calls the corresponding
680 * command handler which does argument checking and further processing.
682 * In order to cope with a DOS attacks, a timeout is set up
683 * which terminates the function if the connection was not
684 * authenticated when the timeout expires.
686 * \sa alarm(2), rc4(3), crypt.c, crypt.h
688 int handle_connect(int fd, struct sockaddr_in *addr)
690 int ret, argc, use_rc4 = 0;
692 unsigned char crypt_buf[MAXLINE];
694 struct server_command *cmd = NULL;
695 long unsigned challenge_nr, chall_response;
697 char *p, *command = NULL;
700 signal(SIGCHLD, SIG_IGN);
701 signal(SIGINT, SIG_DFL);
702 signal(SIGTERM, SIG_DFL);
703 signal(SIGHUP, SIG_DFL);
704 signal(SIGUSR1, SIG_IGN);
706 challenge_nr = random();
707 /* send Welcome message */
708 ret = send_va_buffer(fd, "This is para_server, version "
709 PACKAGE_VERSION ".\n" );
712 /* recv auth request line */
713 ret = recv_buffer(fd, buf, sizeof(buf));
722 if (strncmp(buf, "auth ", 5))
725 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
726 p = buf + 5; /* client version < 0.2.6 */
728 p = buf + 9; /* client version >= 0.2.6 */
731 PARA_DEBUG_LOG("received %s request for user %s\n",
732 use_rc4? "rc4" : "auth", p);
737 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
741 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
742 /* We can't use send_buffer here since buf may contain null bytes */
743 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
746 /* recv decrypted number */
747 ret = recv_buffer(fd, buf, sizeof(buf));
754 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
755 || chall_response != challenge_nr)
757 /* auth successful, send 'Proceed' message */
758 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
759 sprintf(buf, "%s", PROCEED_MSG);
762 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
763 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
766 numbytes = ret + strlen(PROCEED_MSG) + 1;
768 numbytes = strlen(buf);
769 ret = send_bin_buffer(fd, buf, numbytes);
773 enable_crypt(fd, rc4_recv, rc4_send, NULL);
774 ret = read_command(fd, &command);
778 cmd = parse_cmd(command);
781 /* valid command, check permissions */
782 ret = check_perms(u->perms, cmd);
785 /* valid command and sufficient perms */
787 argc = split_args(command, &argv, "\n");
791 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
792 inet_ntoa(addr->sin_addr));
793 ret = cmd->handler(fd, argc, argv);
799 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
800 if (ret != -E_SEND && ret != -E_RECV)
801 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
807 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
809 mmd->active_connections--;