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 does client authentication and executes server commands */
11 #include <sys/types.h>
13 #include <openssl/rc4.h>
16 #include "server.cmdline.h"
17 #include "afs_common.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 audio_file_selector selectors[];
43 extern struct sender senders[];
45 static void dummy(__a_unused int s)
48 static void mmd_dup(struct misc_meta_data *new_mmd)
56 * compute human readable string containing
57 * vss status for given integer value
59 static char *vss_status_tohuman(unsigned int flags)
61 if (flags & VSS_PLAYING)
62 return para_strdup("playing");
63 else if (flags & VSS_NEXT)
64 return para_strdup("stopped");
66 return para_strdup("paused");
70 * return human readable permission string. Never returns NULL.
72 static char *cmd_perms_itohuman(unsigned int perms)
74 char *msg = para_malloc(5 * sizeof(char));
76 msg[0] = perms & AFS_READ? 'a' : '-';
77 msg[1] = perms & AFS_WRITE? 'A' : '-';
78 msg[2] = perms & VSS_READ? 'v' : '-';
79 msg[3] = perms & VSS_WRITE? 'V' : '-';
87 static char *vss_get_status_flags(unsigned int flags)
89 char *msg = para_malloc(5 * sizeof(char));
91 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
92 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
93 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
94 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
100 * compute status bar string. Never returns NULL
102 static char *get_sb_string(struct misc_meta_data *nmmd)
105 long long unsigned secs = 0, rsecs = 0, percent = 0;
107 base = para_basename(nmmd->filename);
109 return para_strdup("");
112 if (nmmd->afi.chunks_total) {
113 secs = (long long) nmmd->afi.seconds_total * nmmd->chunks_sent
114 / nmmd->afi.chunks_total;
115 rsecs = (long long) nmmd->afi.seconds_total *
116 (nmmd->afi.chunks_total - nmmd->chunks_sent)
117 / nmmd->afi.chunks_total;
118 percent = 100 * ((nmmd->chunks_sent + 5) / 10)
119 / ((nmmd->afi.chunks_total + 5) / 10);
121 ret = make_message("%llu:%02llu [%llu:%02llu] (%llu%%) %s",
122 secs / 60, secs % 60,
123 rsecs / 60, rsecs % 60,
131 static char *get_status(struct misc_meta_data *nmmd)
133 char *bar, *ret, mtime[30] = "";
134 char *status, *flags; /* vss status info */
135 char *ut = uptime_str();
136 long offset = (nmmd->offset + 500) / 1000;
140 if (nmmd->audio_format >= 0) {
141 localtime_r(&nmmd->mtime, &mtime_tm);
142 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
144 /* report real status */
145 status = vss_status_tohuman(nmmd->vss_status_flags);
146 flags = vss_get_status_flags(nmmd->vss_status_flags);
147 bar = para_basename(nmmd->filename);
148 gettimeofday(&now, NULL);
150 "%s:%zu\n" "%s:%s\n" "%s:%lu\n" "%s:%u\n"
151 "%s:%s\n" "%s:%s\n" "%s:%s\n" "%s:%s\n"
152 "%s:%li\n" "%s:%s\n" "%s" "%s"
153 "%s:%s\n" "%s:%lu.%lu\n" "%s:%lu.%lu\n",
154 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
155 status_item_list[SI_MTIME], mtime,
156 status_item_list[SI_LENGTH], nmmd->afi.seconds_total,
157 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
159 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
160 status_item_list[SI_STATUS], status,
161 status_item_list[SI_STATUS_FLAGS], flags,
162 status_item_list[SI_SELECTOR], selectors[nmmd->selector_num].name,
164 status_item_list[SI_OFFSET], offset,
165 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
167 nmmd->afi.info_string,
169 status_item_list[SI_UPTIME], ut,
170 status_item_list[SI_STREAM_START],
171 (long unsigned)nmmd->stream_start.tv_sec,
172 (long unsigned)nmmd->stream_start.tv_usec,
173 status_item_list[SI_CURRENT_TIME],
174 (long unsigned)now.tv_sec,
175 (long unsigned)now.tv_usec
185 static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
188 /* this has to match sender.h */
189 const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
191 scd->sender_num = -1;
193 return -E_COMMAND_SYNTAX;
194 for (i = 0; senders[i].name; i++)
195 if (!strcmp(senders[i].name, argv[1]))
197 PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
198 if (!senders[i].name)
199 return -E_COMMAND_SYNTAX;
201 for (i = 0; subcmds[i]; i++)
202 if (!strcmp(subcmds[i], argv[2]))
205 return -E_COMMAND_SYNTAX;
208 if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
210 return -E_SENDER_CMD;
213 switch (scd->cmd_num) {
217 return -E_COMMAND_SYNTAX;
221 if (argc != 4 && argc != 5)
222 return -E_COMMAND_SYNTAX;
223 if (!inet_pton(AF_INET, argv[3], &scd->addr))
224 return -E_COMMAND_SYNTAX;
227 scd->netmask = atoi(argv[4]);
228 if (scd->netmask < 0 || scd->netmask > 32)
229 return -E_COMMAND_SYNTAX;
234 if (argc != 4 && argc != 5)
235 return -E_COMMAND_SYNTAX;
236 if (!inet_pton(AF_INET, argv[3], &scd->addr))
237 return -E_COMMAND_SYNTAX;
240 scd->port = atoi(argv[4]);
241 if (scd->port < 0 || scd->port > 65535)
242 return -E_COMMAND_SYNTAX;
246 return -E_COMMAND_SYNTAX;
251 int com_sender(int fd, int argc, char * const * argv)
254 struct sender_command_data scd;
258 for (i = 0; senders[i].name; i++) {
259 char *tmp = make_message("%s%s\n",
260 msg? msg : "", senders[i].name);
264 ret = send_buffer(fd, msg);
268 ret = check_sender_args(argc, argv, &scd);
271 if (scd.sender_num < 0)
273 msg = senders[scd.sender_num].help();
274 send_buffer(fd, msg);
278 for (i = 0; i < 10; i++) {
280 if (mmd->sender_cmd_data.cmd_num >= 0) {
285 mmd->sender_cmd_data = scd;
289 return (i < 10)? 1 : -E_LOCK;
293 int com_si(int fd, int argc, __a_unused char * const * argv)
297 char *selector_string = NULL, *sender_info = NULL, *sender_list = NULL;
300 return -E_COMMAND_SYNTAX;
302 for (i = 0; selectors[i].name; i++) {
303 selector_string = para_strcat(selector_string, selectors[i].name);
304 selector_string = para_strcat(selector_string, " ");
306 for (i = 0; senders[i].name; i++) {
307 char *info = senders[i].info();
308 sender_info = para_strcat(sender_info, info);
310 sender_list = para_strcat(sender_list, senders[i].name);
311 sender_list = para_strcat(sender_list, " ");
314 ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
316 "connections (active/accepted/total): %u/%u/%u\n"
317 "current loglevel: %i\n"
318 "supported audio file selectors: %s\n"
319 "supported audio formats: %s\n"
320 "supported senders: %s\n"
324 mmd->active_connections,
329 supported_audio_formats(),
335 free(selector_string);
342 int com_version(int fd, int argc, __a_unused char * const * argv)
345 return -E_COMMAND_SYNTAX;
346 return send_buffer(fd, VERSION_TEXT("server")
347 "built: " BUILD_DATE "\n"
348 SYSTEM ", " CC_VERSION "\n"
353 int com_sc(int fd, int argc, char * const * argv)
356 int ret, old = 0, count = -1; /* print af change forever */
359 count = atoi(argv[1]);
362 if (old != mmd->num_played) {
363 old = mmd->num_played;
364 name = para_strdup(mmd->filename);
368 ret = send_va_buffer(fd, "%s\n", name);
373 if (argc > 1 && !--count)
381 int com_sb(int fd, int argc, char * const * argv)
384 int ret, nr = -1; /* status bar will be printed that many
385 * times. Negative value means: print
392 sb = get_sb_string(mmd);
394 ret = send_va_buffer(fd, "%s\n", sb);
408 int com_stat(int fd, int argc, char * const * argv)
410 int ret, num = 0;/* status will be printed that many
411 * times. num <= 0 means: print forever
413 struct misc_meta_data tmp, *nmmd = &tmp;
416 signal(SIGUSR1, dummy);
423 s = get_status(nmmd);
424 ret = send_buffer(fd, s);
433 return -E_SERVER_CRASH;
439 static int send_list_of_commands(int fd, struct server_command *cmd,
444 for (i = 1; cmd->name; cmd++, i++) {
445 char *perms = cmd_perms_itohuman(cmd->perms);
446 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
457 /* always returns string that must be freed by the caller in handler */
458 static struct server_command *get_cmd_ptr(const char *name, char **handler)
460 struct server_command *cmd;
462 for (cmd = server_cmds; cmd->name; cmd++)
463 if (!strcmp(cmd->name, name)) {
465 *handler = para_strdup("para_server"); /* server commands */
468 /* not found, look for commands supported by the current selector */
471 *handler = make_message("the %s selector",
472 selectors[mmd->selector_num].name);
473 cmd = selectors[mmd->selector_num].cmd_list;
475 for (; cmd->name; cmd++)
476 if (!strcmp(cmd->name, name))
478 /* not found, look for commands supported by afs */
479 for (cmd = afs_cmds; cmd->name; cmd++)
480 if (!strcmp(cmd->name, name))
486 int com_help(int fd, int argc, char * const * argv)
488 struct server_command *cmd;
489 char *perms, *handler;
493 /* no argument given, print list of commands */
494 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
497 handler = para_strdup(selectors[mmd->selector_num].name);
498 cmd = selectors[mmd->selector_num].cmd_list;
500 ret = send_list_of_commands(fd, cmd, handler);
505 return send_list_of_commands(fd, cmd, "afs");
507 /* argument given for help */
508 cmd = get_cmd_ptr(argv[1], &handler);
513 perms = cmd_perms_itohuman(cmd->perms);
514 ret = send_va_buffer(fd,
533 int com_hup(__a_unused int fd, int argc, __a_unused char * const * argv)
536 return -E_COMMAND_SYNTAX;
537 kill(getppid(), SIGHUP);
542 int com_term(__a_unused int fd, int argc, __a_unused char * const * argv)
545 return -E_COMMAND_SYNTAX;
546 kill(getppid(), SIGTERM);
550 int com_play(__a_unused int fd, int argc, __a_unused char * const * argv)
553 return -E_COMMAND_SYNTAX;
555 mmd->new_vss_status_flags |= VSS_PLAYING;
556 mmd->new_vss_status_flags &= ~VSS_NOMORE;
563 int com_stop(__a_unused int fd, int argc, __a_unused char * const * argv)
566 return -E_COMMAND_SYNTAX;
568 mmd->new_vss_status_flags &= ~VSS_PLAYING;
569 mmd->new_vss_status_flags &= ~VSS_REPOS;
570 mmd->new_vss_status_flags |= VSS_NEXT;
576 int com_pause(__a_unused int fd, int argc, __a_unused char * const * argv)
579 return -E_COMMAND_SYNTAX;
583 mmd->new_vss_status_flags &= ~VSS_PLAYING;
584 mmd->new_vss_status_flags &= ~VSS_NEXT;
589 int com_chs(int fd, int argc, char * const * argv)
596 selector = para_strdup(selectors[mmd->selector_num].name);
598 ret = send_va_buffer(fd, "%s\n", selector);
602 for (i = 0; selectors[i].name; i++) {
603 if (strcmp(selectors[i].name, argv[1]))
606 mmd->selector_change = i;
611 return -E_BAD_SELECTOR;
615 int com_next(__a_unused int fd, int argc, __a_unused char * const * argv)
618 return -E_COMMAND_SYNTAX;
621 mmd->new_vss_status_flags |= VSS_NEXT;
627 int com_nomore(__a_unused int fd, int argc, __a_unused char * const * argv)
630 return -E_COMMAND_SYNTAX;
632 if (vss_playing() || vss_paused())
633 mmd->new_vss_status_flags |= VSS_NOMORE;
639 int com_ff(__a_unused int fd, int argc, char * const * argv)
642 int ret, backwards = 0;
647 return -E_COMMAND_SYNTAX;
648 if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
649 return -E_COMMAND_SYNTAX;
650 if (ret > 1 && c == '-')
651 backwards = 1; /* jmp backwards */
653 ret = -E_NO_AUDIO_FILE;
654 if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
656 promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
658 promille -= 1000 * i / mmd->afi.seconds_total;
660 promille += 1000 * i / mmd->afi.seconds_total;
663 if (promille > 1000) {
664 mmd->new_vss_status_flags |= VSS_NEXT;
667 mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
668 mmd->new_vss_status_flags |= VSS_REPOS;
669 mmd->new_vss_status_flags &= ~VSS_NEXT;
678 int com_jmp(__a_unused int fd, int argc, char * const * argv)
684 return -E_COMMAND_SYNTAX;
685 if (sscanf(argv[1], "%lu", &i) <= 0)
686 return -E_COMMAND_SYNTAX;
688 ret = -E_NO_AUDIO_FILE;
689 if (!mmd->afi.chunks_total)
693 PARA_INFO_LOG("jumping to %lu%%\n", i);
694 mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
695 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
696 mmd->chunks_sent, mmd->offset);
697 mmd->new_vss_status_flags |= VSS_REPOS;
698 mmd->new_vss_status_flags &= ~VSS_NEXT;
707 * check if perms are sufficient to exec a command having perms cmd_perms.
708 * Returns 0 if perms are sufficient, -E_PERM otherwise.
710 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
712 PARA_DEBUG_LOG("%s", "checking permissions\n");
713 return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
717 * Parse first string from *cmd and lookup in table of valid commands.
718 * On error, NULL is returned.
720 static struct server_command *parse_cmd(const char *cmdstr)
725 sscanf(cmdstr, "%200s%n", buf, &n);
729 return get_cmd_ptr(buf, NULL);
732 static long int para_rand(long unsigned max)
734 return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
737 static void init_rc4_keys(void)
741 for (i = 0; i < 2 * RC4_KEY_LEN; i++)
742 rc4_buf[i] = para_rand(256);
743 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
744 (unsigned char) rc4_buf[0],
745 (unsigned char) rc4_buf[RC4_KEY_LEN]);
746 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
747 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
750 static void rc4_recv(unsigned long len, const unsigned char *indata,
751 unsigned char *outdata, __a_unused void *private_data)
753 RC4(&rc4_recv_key, len, indata, outdata);
756 static void rc4_send(unsigned long len, const unsigned char *indata,
757 unsigned char *outdata, __a_unused void *private_data)
759 RC4(&rc4_send_key, len, indata, outdata);
762 static int read_command(int fd, char **result)
766 char *command = NULL;
772 ret = recv_buffer(fd, buf, sizeof(buf));
778 ret = -E_COMMAND_SYNTAX;
779 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
781 command = para_strcat(command, buf);
782 p = strstr(command, EOC_MSG);
788 ret = command? 1 : -E_COMMAND_SYNTAX;
799 * perform user authentication and execute a command
801 * \param fd the file descriptor to send output to
802 * \param addr socket address info of peer
804 * \return EXIT_SUCCESS or EXIT_FAILURE
806 * Whenever para_server accepts an incoming tcp connection on
807 * the port it listens on, it forks and the resulting child
808 * calls this function.
810 * An RSA-based challenge/response is used to authenticate
811 * the peer. It that authentication succeeds, a random RC4
812 * session key is generated and sent back to the peer,
813 * encrypted with its RSA public key. From this point on,
814 * all transfers are crypted with this session key.
816 * Next it is checked if the peer supplied a valid server
817 * command or a command for the audio file selector currently
818 * in use. If yes, and if the user has sufficient
819 * permissions to execute that command, the function calls
820 * the corresponding command handler which does argument
821 * checking and further processing.
823 * In order to cope with a DOS attacks, a timeout is set up
824 * which terminates the function if the connection was not
825 * authenticated when the timeout expires.
827 * \sa alarm(2), rc4(3), crypt.c, crypt.h
829 int handle_connect(int fd, struct sockaddr_in *addr)
831 int ret, argc, use_rc4 = 0;
833 unsigned char crypt_buf[MAXLINE];
835 struct server_command *cmd = NULL;
836 long unsigned challenge_nr, chall_response;
838 char *p, *command = NULL;
841 signal(SIGCHLD, SIG_IGN);
842 signal(SIGINT, SIG_DFL);
843 signal(SIGTERM, SIG_DFL);
844 signal(SIGHUP, SIG_DFL);
845 signal(SIGUSR1, SIG_IGN);
847 challenge_nr = random();
848 /* send Welcome message */
849 ret = send_va_buffer(fd, "This is para_server, version "
850 PACKAGE_VERSION ".\n" );
853 /* recv auth request line */
854 ret = recv_buffer(fd, buf, sizeof(buf));
863 if (strncmp(buf, "auth ", 5))
866 if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
867 p = buf + 5; /* client version < 0.2.6 */
869 p = buf + 9; /* client version >= 0.2.6 */
872 PARA_DEBUG_LOG("received %s request for user %s\n",
873 use_rc4? "rc4" : "auth", p);
878 ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
882 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
883 /* We can't use send_buffer here since buf may contain null bytes */
884 ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
887 /* recv decrypted number */
888 ret = recv_buffer(fd, buf, sizeof(buf));
895 if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
896 || chall_response != challenge_nr)
898 /* auth successful, send 'Proceed' message */
899 PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
900 sprintf(buf, "%s", PROCEED_MSG);
903 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
904 (unsigned char *)buf + PROCEED_MSG_LEN + 1);
907 numbytes = ret + strlen(PROCEED_MSG) + 1;
909 numbytes = strlen(buf);
910 ret = send_bin_buffer(fd, buf, numbytes);
914 enable_crypt(fd, rc4_recv, rc4_send, NULL);
915 ret = read_command(fd, &command);
919 cmd = parse_cmd(command);
922 /* valid command, check permissions */
923 ret = check_perms(u->perms, cmd);
926 /* valid command and sufficient perms */
928 argc = split_args(command, &argv, "\n");
932 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
933 inet_ntoa(addr->sin_addr));
934 ret = cmd->handler(fd, argc, argv);
940 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
941 if (ret != -E_SEND && ret != -E_RECV)
942 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
948 if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
950 mmd->active_connections--;