2 * Copyright (C) 1997-2012 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. */
12 #include <sys/types.h>
19 #include "server.cmdline.h"
32 #include "user_list.h"
33 #include "server_command_list.h"
34 #include "afs_command_list.h"
38 /** Commands including options must be shorter than this. */
39 #define MAX_COMMAND_LEN 32768
42 extern struct misc_meta_data
*mmd
;
43 extern struct sender senders
[];
44 int send_afs_status(struct command_context
*cc
, int parser_friendly
);
46 const char *status_item_list
[] = {STATUS_ITEM_ARRAY
};
48 static void dummy(__a_unused
int s
)
52 static void mmd_dup(struct misc_meta_data
*new_mmd
)
54 mutex_lock(mmd_mutex
);
56 mutex_unlock(mmd_mutex
);
60 * Compute human readable string containing vss status for given integer value.
62 * We don't want to use vss_playing() and friends here because we take a
63 * snapshot of the mmd struct and use the copy for computing the state of the
64 * vss. If the real data were used, we would take the mmd lock for a rather
65 * long time or risk to get an inconsistent view.
67 static char *vss_status_tohuman(unsigned int flags
)
69 if (flags
& VSS_PLAYING
)
70 return para_strdup("playing");
72 return para_strdup("stopped");
73 return para_strdup("paused");
77 * return human readable permission string. Never returns NULL.
79 static char *cmd_perms_itohuman(unsigned int perms
)
81 char *msg
= para_malloc(5 * sizeof(char));
83 msg
[0] = perms
& AFS_READ
? 'a' : '-';
84 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
85 msg
[2] = perms
& VSS_READ
? 'v' : '-';
86 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
94 static char *vss_get_status_flags(unsigned int flags
)
96 char *msg
= para_malloc(5 * sizeof(char));
98 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
99 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
100 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
101 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
106 static char *get_status(struct misc_meta_data
*nmmd
, int parser_friendly
)
109 char *status
, *flags
; /* vss status info */
110 /* nobody updates our version of "now" */
111 char *ut
= get_server_uptime_str(NULL
);
112 long offset
= (nmmd
->offset
+ 500) / 1000;
113 struct timeval current_time
;
115 struct para_buffer b
= {.flags
= parser_friendly
? PBF_SIZE_PREFIX
: 0};
117 /* report real status */
118 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
119 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
120 if (nmmd
->size
) { /* parent currently has an audio file open */
121 localtime_r(&nmmd
->mtime
, &mtime_tm
);
122 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
124 gettimeofday(¤t_time
, NULL
);
126 * The calls to WRITE_STATUS_ITEM() below never fail because
127 * b->max_size is zero (unlimited), see para_printf(). However, clang
128 * is not smart enough to prove this and complains nevertheless.
129 * Casting the return value to void silences clang.
131 (void)WRITE_STATUS_ITEM(&b
, SI_FILE_SIZE
, "%zu\n", nmmd
->size
/ 1024);
132 (void)WRITE_STATUS_ITEM(&b
, SI_MTIME
, "%s\n", mtime
);
133 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
134 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
135 (void)WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
136 (void)WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
137 (void)WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
138 (long unsigned)nmmd
->stream_start
.tv_sec
,
139 (long unsigned)nmmd
->stream_start
.tv_usec
);
140 (void)WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
141 (long unsigned)current_time
.tv_sec
,
142 (long unsigned)current_time
.tv_usec
);
149 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
152 /* this has to match sender.h */
153 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
155 scd
->sender_num
= -1;
157 return -E_COMMAND_SYNTAX
;
158 for (i
= 0; senders
[i
].name
; i
++)
159 if (!strcmp(senders
[i
].name
, argv
[1]))
161 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
162 if (!senders
[i
].name
)
163 return -E_COMMAND_SYNTAX
;
165 for (i
= 0; subcmds
[i
]; i
++)
166 if (!strcmp(subcmds
[i
], argv
[2]))
169 return -E_COMMAND_SYNTAX
;
171 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
172 return -E_SENDER_CMD
;
173 switch (scd
->cmd_num
) {
177 return -E_COMMAND_SYNTAX
;
181 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
182 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
183 return -E_COMMAND_SYNTAX
;
188 return -E_COMMAND_SYNTAX
;
189 return parse_fec_url(argv
[3], scd
);
191 return -E_COMMAND_SYNTAX
;
196 int com_sender(struct command_context
*cc
)
200 struct sender_command_data scd
;
203 for (i
= 0; senders
[i
].name
; i
++) {
204 char *tmp
= make_message("%s%s\n",
205 msg
? msg
: "", senders
[i
].name
);
209 ret
= sc_send_buffer(&cc
->scc
, msg
);
213 ret
= check_sender_args(cc
->argc
, cc
->argv
, &scd
);
215 if (scd
.sender_num
< 0)
217 msg
= senders
[scd
.sender_num
].help();
218 ret
= sc_send_buffer(&cc
->scc
, msg
);
223 switch (scd
.cmd_num
) {
226 assert(senders
[scd
.sender_num
].resolve_target
);
227 ret
= senders
[scd
.sender_num
].resolve_target(cc
->argv
[3], &scd
);
232 for (i
= 0; i
< 10; i
++) {
233 mutex_lock(mmd_mutex
);
234 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
235 mutex_unlock(mmd_mutex
);
239 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
240 mutex_unlock(mmd_mutex
);
243 return (i
< 10)? 1 : -E_LOCK
;
247 int com_si(struct command_context
*cc
)
251 char *sender_info
= NULL
;
254 return -E_COMMAND_SYNTAX
;
255 mutex_lock(mmd_mutex
);
256 for (i
= 0; senders
[i
].name
; i
++) {
257 char *info
= senders
[i
].info();
258 sender_info
= para_strcat(sender_info
, info
);
261 ut
= get_server_uptime_str(now
);
262 ret
= sc_send_va_buffer(&cc
->scc
, "version: " GIT_VERSION
"\n"
263 "up: %s\nplayed: %u\n"
266 "connections (active/accepted/total): %u/%u/%u\n"
267 "current loglevel: %s\n"
268 "supported audio formats: %s\n"
273 mmd
->active_connections
,
277 SERVER_AUDIO_FORMATS
,
280 mutex_unlock(mmd_mutex
);
287 int com_version(struct command_context
*cc
)
290 return -E_COMMAND_SYNTAX
;
291 return sc_send_buffer(&cc
->scc
, VERSION_TEXT("server")
292 "built: " BUILD_DATE
"\n"
293 UNAME_RS
", " CC_VERSION
"\n"
297 #define EMPTY_STATUS_ITEMS \
302 ITEM(ATTRIBUTES_BITMAP) \
303 ITEM(ATTRIBUTES_TXT) \
314 ITEM(SECONDS_TOTAL) \
326 * Write a list of audio-file related status items with empty values.
328 * This is used by vss when currently no audio file is open.
330 static char *empty_status_items(int parser_friendly
)
334 #define ITEM(x) "0004 %02x:\n"
337 #define ITEM(x) , SI_ ## x
342 #define ITEM(x) "%s:\n"
345 #define ITEM(x) ,status_item_list[SI_ ## x]
350 #undef EMPTY_STATUS_ITEMS
353 int com_stat(struct command_context
*cc
)
356 struct misc_meta_data tmp
, *nmmd
= &tmp
;
359 int parser_friendly
= 0;
361 para_sigaction(SIGUSR1
, dummy
);
363 for (i
= 1; i
< cc
->argc
; i
++) {
364 const char *arg
= cc
->argv
[i
];
367 if (!strcmp(arg
, "--")) {
371 if (!strncmp(arg
, "-n=", 3)) {
372 ret
= para_atoi32(arg
+ 3, &num
);
377 if (!strcmp(arg
, "-p")) {
381 return -E_COMMAND_SYNTAX
;
384 return -E_COMMAND_SYNTAX
;
387 s
= get_status(nmmd
, parser_friendly
);
388 ret
= sc_send_buffer(&cc
->scc
, s
);
392 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
395 esi
= empty_status_items(parser_friendly
);
396 ret
= sc_send_buffer(&cc
->scc
, esi
);
400 send_afs_status(cc
, parser_friendly
);
402 if (num
> 0 && !--num
)
406 return -E_SERVER_CRASH
;
412 static int send_list_of_commands(struct stream_cipher_context
*scc
, struct server_command
*cmd
,
417 for (i
= 1; cmd
->name
; cmd
++, i
++) {
418 char *perms
= cmd_perms_itohuman(cmd
->perms
);
419 ret
= sc_send_va_buffer(scc
, "%s\t%s\t%s\t%s\n", cmd
->name
,
430 /* returns string that must be freed by the caller */
431 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
433 struct server_command
*cmd
;
435 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
436 if (!strcmp(cmd
->name
, name
)) {
438 *handler
= para_strdup("server"); /* server commands */
441 /* not found, look for commands supported by afs */
442 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
443 if (!strcmp(cmd
->name
, name
)) {
445 *handler
= para_strdup("afs");
452 int com_help(struct command_context
*cc
)
454 struct server_command
*cmd
;
455 char *perms
, *handler
;
459 /* no argument given, print list of commands */
460 if ((ret
= send_list_of_commands(&cc
->scc
, server_cmds
, "server")) < 0)
462 return send_list_of_commands(&cc
->scc
, afs_cmds
, "afs");
464 /* argument given for help */
465 cmd
= get_cmd_ptr(cc
->argv
[1], &handler
);
468 perms
= cmd_perms_itohuman(cmd
->perms
);
469 ret
= sc_send_va_buffer(&cc
->scc
,
488 int com_hup(struct command_context
*cc
)
491 return -E_COMMAND_SYNTAX
;
492 kill(getppid(), SIGHUP
);
497 int com_term(struct command_context
*cc
)
500 return -E_COMMAND_SYNTAX
;
501 kill(getppid(), SIGTERM
);
505 int com_play(struct command_context
*cc
)
508 return -E_COMMAND_SYNTAX
;
509 mutex_lock(mmd_mutex
);
510 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
511 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
512 mutex_unlock(mmd_mutex
);
517 int com_stop(struct command_context
*cc
)
520 return -E_COMMAND_SYNTAX
;
521 mutex_lock(mmd_mutex
);
522 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
523 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
524 mmd
->new_vss_status_flags
|= VSS_NEXT
;
525 mutex_unlock(mmd_mutex
);
530 int com_pause(struct command_context
*cc
)
533 return -E_COMMAND_SYNTAX
;
534 mutex_lock(mmd_mutex
);
535 if (!vss_paused() && !vss_stopped()) {
537 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
538 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
540 mutex_unlock(mmd_mutex
);
545 int com_next(struct command_context
*cc
)
548 return -E_COMMAND_SYNTAX
;
549 mutex_lock(mmd_mutex
);
551 mmd
->new_vss_status_flags
|= VSS_NEXT
;
552 mutex_unlock(mmd_mutex
);
557 int com_nomore(struct command_context
*cc
)
560 return -E_COMMAND_SYNTAX
;
561 mutex_lock(mmd_mutex
);
562 if (vss_playing() || vss_paused())
563 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
564 mutex_unlock(mmd_mutex
);
569 int com_ff(struct command_context
*cc
)
572 int ret
, backwards
= 0;
577 return -E_COMMAND_SYNTAX
;
578 if (!(ret
= sscanf(cc
->argv
[1], "%u%c", &i
, &c
)))
579 return -E_COMMAND_SYNTAX
;
580 if (ret
> 1 && c
== '-')
581 backwards
= 1; /* jmp backwards */
582 mutex_lock(mmd_mutex
);
583 ret
= -E_NO_AUDIO_FILE
;
584 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
586 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
588 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
590 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
593 if (promille
> 1000) {
594 mmd
->new_vss_status_flags
|= VSS_NEXT
;
597 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
598 mmd
->new_vss_status_flags
|= VSS_REPOS
;
599 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
603 mutex_unlock(mmd_mutex
);
608 int com_jmp(struct command_context
*cc
)
614 return -E_COMMAND_SYNTAX
;
615 if (sscanf(cc
->argv
[1], "%lu", &i
) <= 0)
616 return -E_COMMAND_SYNTAX
;
617 mutex_lock(mmd_mutex
);
618 ret
= -E_NO_AUDIO_FILE
;
619 if (!mmd
->afd
.afhi
.chunks_total
)
623 PARA_INFO_LOG("jumping to %lu%%\n", i
);
624 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
625 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
626 mmd
->chunks_sent
, mmd
->offset
);
627 mmd
->new_vss_status_flags
|= VSS_REPOS
;
628 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
632 mutex_unlock(mmd_mutex
);
637 * check if perms are sufficient to exec a command having perms cmd_perms.
638 * Returns 0 if perms are sufficient, -E_PERM otherwise.
640 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
642 PARA_DEBUG_LOG("checking permissions\n");
643 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
647 * Parse first string from *cmd and lookup in table of valid commands.
648 * On error, NULL is returned.
650 static struct server_command
*parse_cmd(const char *cmdstr
)
655 sscanf(cmdstr
, "%200s%n", buf
, &n
);
659 return get_cmd_ptr(buf
, NULL
);
662 static int read_command(struct stream_cipher_context
*scc
, char **result
)
666 char *command
= NULL
;
672 ret
= sc_recv_buffer(scc
, buf
, sizeof(buf
));
678 ret
= -E_COMMAND_SYNTAX
;
679 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
681 command
= para_strcat(command
, buf
);
682 p
= strstr(command
, EOC_MSG
);
688 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
698 static void reset_signals(void)
700 para_sigaction(SIGCHLD
, SIG_IGN
);
701 para_sigaction(SIGINT
, SIG_DFL
);
702 para_sigaction(SIGTERM
, SIG_DFL
);
703 para_sigaction(SIGHUP
, SIG_DFL
);
707 * Perform user authentication and execute a command.
709 * \param fd The file descriptor to send output to.
710 * \param peername Identifies the connecting peer.
712 * Whenever para_server accepts an incoming tcp connection on
713 * the port it listens on, it forks and the resulting child
714 * calls this function.
716 * An RSA-based challenge/response is used to authenticate
717 * the peer. It that authentication succeeds, a random
718 * session key is generated and sent back to the peer,
719 * encrypted with its RSA public key. From this point on,
720 * all transfers are crypted with this session key.
722 * Next it is checked if the peer supplied a valid server command or a command
723 * for the audio file selector. If yes, and if the user has sufficient
724 * permissions to execute that command, the function calls the corresponding
725 * command handler which does argument checking and further processing.
727 * In order to cope with a DOS attacks, a timeout is set up
728 * which terminates the function if the connection was not
729 * authenticated when the timeout expires.
731 * \sa alarm(2), crypt.c, crypt.h
733 __noreturn
void handle_connect(int fd
, const char *peername
)
737 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * SESSION_KEY_LEN
];
738 unsigned char challenge_hash
[HASH_SIZE
];
739 char *p
, *command
= NULL
;
741 struct command_context cc_struct
= {.peer
= peername
}, *cc
= &cc_struct
;
745 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
746 ret
= mark_fd_blocking(fd
);
749 /* send Welcome message */
750 ret
= write_va_buffer(fd
, "This is para_server, version "
751 PACKAGE_VERSION
".\n" );
754 /* recv auth request line */
755 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
759 ret
= -E_AUTH_REQUEST
;
762 ret
= -E_AUTH_REQUEST
;
763 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
765 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
766 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
767 cc
->u
= lookup_user(p
);
769 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
770 ret
= pub_encrypt(cc
->u
->pubkey
, rand_buf
, sizeof(rand_buf
),
771 (unsigned char *)buf
);
777 * We don't want to reveal our user names, so we send a
778 * challenge to the client even if the user does not exist, and
779 * fail the authentication later.
782 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
784 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
785 CHALLENGE_SIZE
, numbytes
);
786 ret
= write_all(fd
, buf
, numbytes
);
789 /* recv challenge response */
790 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
794 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret
);
799 * The correct response is the hash of the first CHALLENGE_SIZE bytes
800 * of the random data.
803 if (numbytes
!= HASH_SIZE
)
805 hash_function((char *)rand_buf
, CHALLENGE_SIZE
, challenge_hash
);
806 if (memcmp(challenge_hash
, buf
, HASH_SIZE
))
808 /* auth successful */
810 PARA_INFO_LOG("good auth for %s\n", cc
->u
->name
);
811 /* init stream cipher keys with the second part of the random buffer */
812 cc
->scc
.recv
= sc_new(rand_buf
+ CHALLENGE_SIZE
, SESSION_KEY_LEN
);
813 cc
->scc
.send
= sc_new(rand_buf
+ CHALLENGE_SIZE
+ SESSION_KEY_LEN
, SESSION_KEY_LEN
);
814 ret
= sc_send_buffer(&cc
->scc
, PROCEED_MSG
);
817 ret
= read_command(&cc
->scc
, &command
);
818 if (ret
== -E_COMMAND_SYNTAX
)
823 cc
->cmd
= parse_cmd(command
);
826 /* valid command, check permissions */
827 ret
= check_perms(cc
->u
->perms
, cc
->cmd
);
830 /* valid command and sufficient perms */
831 ret
= create_argv(command
, "\n", &cc
->argv
);
835 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cc
->cmd
->name
,
836 cc
->u
->name
, peername
);
837 ret
= cc
->cmd
->handler(cc
);
839 mutex_lock(mmd_mutex
);
841 mutex_unlock(mmd_mutex
);
845 sc_send_va_buffer(&cc
->scc
, "%s\n", para_strerror(-ret
));
847 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
850 sc_free(cc
->scc
.recv
);
851 sc_free(cc
->scc
.send
);
852 mutex_lock(mmd_mutex
);
853 if (cc
->cmd
&& (cc
->cmd
->perms
& AFS_WRITE
) && ret
>= 0)
855 mmd
->active_connections
--;
856 mutex_unlock(mmd_mutex
);
857 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);