2 * Copyright (C) 1997-2011 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>
20 #include "server.cmdline.h"
32 #include "user_list.h"
33 #include "server_command_list.h"
34 #include "afs_command_list.h"
39 /** Commands including options must be shorter than this. */
40 #define MAX_COMMAND_LEN 32768
43 extern struct misc_meta_data
*mmd
;
44 extern struct sender senders
[];
45 int send_afs_status(struct stream_cipher_context
*scc
, int parser_friendly
);
47 const char *status_item_list
[] = {STATUS_ITEM_ARRAY
};
49 static void dummy(__a_unused
int s
)
53 static void mmd_dup(struct misc_meta_data
*new_mmd
)
55 mutex_lock(mmd_mutex
);
57 mutex_unlock(mmd_mutex
);
61 * Compute human readable string containing vss status for given integer value.
63 * We don't want to use vss_playing() and friends here because we take a
64 * snapshot of the mmd struct and use the copy for computing the state of the
65 * vss. If the real data were used, we would take the mmd lock for a rather
66 * long time or risk to get an inconsistent view.
68 static char *vss_status_tohuman(unsigned int flags
)
70 if (flags
& VSS_PLAYING
)
71 return para_strdup("playing");
73 return para_strdup("stopped");
74 return para_strdup("paused");
78 * return human readable permission string. Never returns NULL.
80 static char *cmd_perms_itohuman(unsigned int perms
)
82 char *msg
= para_malloc(5 * sizeof(char));
84 msg
[0] = perms
& AFS_READ
? 'a' : '-';
85 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
86 msg
[2] = perms
& VSS_READ
? 'v' : '-';
87 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
95 static char *vss_get_status_flags(unsigned int flags
)
97 char *msg
= para_malloc(5 * sizeof(char));
99 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
100 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
101 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
102 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
107 static char *get_status(struct misc_meta_data
*nmmd
, int parser_friendly
)
110 char *status
, *flags
; /* vss status info */
111 /* nobody updates our version of "now" */
112 char *ut
= get_server_uptime_str(NULL
);
113 long offset
= (nmmd
->offset
+ 500) / 1000;
114 struct timeval current_time
;
116 struct para_buffer b
= {.flags
= parser_friendly
? PBF_SIZE_PREFIX
: 0};
118 /* report real status */
119 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
120 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
121 if (nmmd
->size
) { /* parent currently has an audio file open */
122 localtime_r(&nmmd
->mtime
, &mtime_tm
);
123 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
125 gettimeofday(¤t_time
, NULL
);
127 * The calls to WRITE_STATUS_ITEM() below never fail because
128 * b->max_size is zero (unlimited), see para_printf(). However, clang
129 * is not smart enough to prove this and complains nevertheless.
130 * Casting the return value to void silences solves this.
132 (void)WRITE_STATUS_ITEM(&b
, SI_FILE_SIZE
, "%zu\n", nmmd
->size
/ 1024);
133 (void)WRITE_STATUS_ITEM(&b
, SI_MTIME
, "%s\n", mtime
);
134 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
135 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
136 (void)WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
137 (void)WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
138 (void)WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
139 (long unsigned)nmmd
->stream_start
.tv_sec
,
140 (long unsigned)nmmd
->stream_start
.tv_usec
);
141 (void)WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
142 (long unsigned)current_time
.tv_sec
,
143 (long unsigned)current_time
.tv_usec
);
150 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
153 /* this has to match sender.h */
154 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
156 scd
->sender_num
= -1;
158 return -E_COMMAND_SYNTAX
;
159 for (i
= 0; senders
[i
].name
; i
++)
160 if (!strcmp(senders
[i
].name
, argv
[1]))
162 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
163 if (!senders
[i
].name
)
164 return -E_COMMAND_SYNTAX
;
166 for (i
= 0; subcmds
[i
]; i
++)
167 if (!strcmp(subcmds
[i
], argv
[2]))
170 return -E_COMMAND_SYNTAX
;
172 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
173 return -E_SENDER_CMD
;
174 switch (scd
->cmd_num
) {
178 return -E_COMMAND_SYNTAX
;
182 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
183 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
184 return -E_COMMAND_SYNTAX
;
189 return -E_COMMAND_SYNTAX
;
190 return parse_fec_url(argv
[3], scd
);
192 return -E_COMMAND_SYNTAX
;
197 int com_sender(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
201 struct sender_command_data scd
;
204 for (i
= 0; senders
[i
].name
; i
++) {
205 char *tmp
= make_message("%s%s\n",
206 msg
? msg
: "", senders
[i
].name
);
210 ret
= sc_send_buffer(scc
, msg
);
214 ret
= check_sender_args(argc
, argv
, &scd
);
216 if (scd
.sender_num
< 0)
218 msg
= senders
[scd
.sender_num
].help();
219 ret
= sc_send_buffer(scc
, msg
);
224 switch (scd
.cmd_num
) {
227 assert(senders
[scd
.sender_num
].resolve_target
);
228 ret
= senders
[scd
.sender_num
].resolve_target(argv
[3], &scd
);
233 for (i
= 0; i
< 10; i
++) {
234 mutex_lock(mmd_mutex
);
235 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
236 mutex_unlock(mmd_mutex
);
240 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
241 mutex_unlock(mmd_mutex
);
244 return (i
< 10)? 1 : -E_LOCK
;
248 int com_si(struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
252 char *sender_info
= NULL
;
255 return -E_COMMAND_SYNTAX
;
256 mutex_lock(mmd_mutex
);
257 for (i
= 0; senders
[i
].name
; i
++) {
258 char *info
= senders
[i
].info();
259 sender_info
= para_strcat(sender_info
, info
);
262 ut
= get_server_uptime_str(now
);
263 ret
= sc_send_va_buffer(scc
, "version: " GIT_VERSION
"\n"
264 "up: %s\nplayed: %u\n"
267 "connections (active/accepted/total): %u/%u/%u\n"
268 "current loglevel: %s\n"
269 "supported audio formats: %s\n"
274 mmd
->active_connections
,
278 SERVER_AUDIO_FORMATS
,
281 mutex_unlock(mmd_mutex
);
288 int com_version(struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
291 return -E_COMMAND_SYNTAX
;
292 return sc_send_buffer(scc
, VERSION_TEXT("server")
293 "built: " BUILD_DATE
"\n"
294 UNAME_RS
", " CC_VERSION
"\n"
298 #define EMPTY_STATUS_ITEMS \
303 ITEM(ATTRIBUTES_BITMAP) \
304 ITEM(ATTRIBUTES_TXT) \
315 ITEM(SECONDS_TOTAL) \
327 * Write a list of audio-file related status items with empty values.
329 * This is used by vss when currently no audio file is open.
331 static char *empty_status_items(int parser_friendly
)
335 #define ITEM(x) "0004 %02x:\n"
338 #define ITEM(x) , SI_ ## x
343 #define ITEM(x) "%s:\n"
346 #define ITEM(x) ,status_item_list[SI_ ## x]
351 #undef EMPTY_STATUS_ITEMS
354 int com_stat(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
357 struct misc_meta_data tmp
, *nmmd
= &tmp
;
360 int parser_friendly
= 0;
362 para_sigaction(SIGUSR1
, dummy
);
364 for (i
= 1; i
< argc
; i
++) {
365 const char *arg
= argv
[i
];
368 if (!strcmp(arg
, "--")) {
372 if (!strncmp(arg
, "-n=", 3)) {
373 ret
= para_atoi32(arg
+ 3, &num
);
378 if (!strcmp(arg
, "-p")) {
382 return -E_COMMAND_SYNTAX
;
385 return -E_COMMAND_SYNTAX
;
388 s
= get_status(nmmd
, parser_friendly
);
389 ret
= sc_send_buffer(scc
, s
);
393 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
396 esi
= empty_status_items(parser_friendly
);
397 ret
= sc_send_buffer(scc
, esi
);
401 send_afs_status(scc
, parser_friendly
);
403 if (num
> 0 && !--num
)
407 return -E_SERVER_CRASH
;
413 static int send_list_of_commands(struct stream_cipher_context
*scc
, struct server_command
*cmd
,
418 for (i
= 1; cmd
->name
; cmd
++, i
++) {
419 char *perms
= cmd_perms_itohuman(cmd
->perms
);
420 ret
= sc_send_va_buffer(scc
, "%s\t%s\t%s\t%s\n", cmd
->name
,
431 /* returns string that must be freed by the caller */
432 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
434 struct server_command
*cmd
;
436 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
437 if (!strcmp(cmd
->name
, name
)) {
439 *handler
= para_strdup("server"); /* server commands */
442 /* not found, look for commands supported by afs */
443 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
444 if (!strcmp(cmd
->name
, name
)) {
446 *handler
= para_strdup("afs");
453 int com_help(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
455 struct server_command
*cmd
;
456 char *perms
, *handler
;
460 /* no argument given, print list of commands */
461 if ((ret
= send_list_of_commands(scc
, server_cmds
, "server")) < 0)
463 return send_list_of_commands(scc
, afs_cmds
, "afs");
465 /* argument given for help */
466 cmd
= get_cmd_ptr(argv
[1], &handler
);
469 perms
= cmd_perms_itohuman(cmd
->perms
);
470 ret
= sc_send_va_buffer(scc
,
489 int com_hup(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
492 return -E_COMMAND_SYNTAX
;
493 kill(getppid(), SIGHUP
);
498 int com_term(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
501 return -E_COMMAND_SYNTAX
;
502 kill(getppid(), SIGTERM
);
506 int com_play(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
509 return -E_COMMAND_SYNTAX
;
510 mutex_lock(mmd_mutex
);
511 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
512 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
513 mutex_unlock(mmd_mutex
);
519 int com_stop(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
522 return -E_COMMAND_SYNTAX
;
523 mutex_lock(mmd_mutex
);
524 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
525 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
526 mmd
->new_vss_status_flags
|= VSS_NEXT
;
527 mutex_unlock(mmd_mutex
);
532 int com_pause(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
535 return -E_COMMAND_SYNTAX
;
536 mutex_lock(mmd_mutex
);
537 if (!vss_paused() && !vss_stopped()) {
539 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
540 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
542 mutex_unlock(mmd_mutex
);
547 int com_next(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
550 return -E_COMMAND_SYNTAX
;
551 mutex_lock(mmd_mutex
);
553 mmd
->new_vss_status_flags
|= VSS_NEXT
;
554 mutex_unlock(mmd_mutex
);
559 int com_nomore(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
562 return -E_COMMAND_SYNTAX
;
563 mutex_lock(mmd_mutex
);
564 if (vss_playing() || vss_paused())
565 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
566 mutex_unlock(mmd_mutex
);
571 int com_ff(__a_unused
struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
574 int ret
, backwards
= 0;
579 return -E_COMMAND_SYNTAX
;
580 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
581 return -E_COMMAND_SYNTAX
;
582 if (ret
> 1 && c
== '-')
583 backwards
= 1; /* jmp backwards */
584 mutex_lock(mmd_mutex
);
585 ret
= -E_NO_AUDIO_FILE
;
586 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
588 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
590 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
592 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
595 if (promille
> 1000) {
596 mmd
->new_vss_status_flags
|= VSS_NEXT
;
599 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
600 mmd
->new_vss_status_flags
|= VSS_REPOS
;
601 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
605 mutex_unlock(mmd_mutex
);
610 int com_jmp(__a_unused
struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
616 return -E_COMMAND_SYNTAX
;
617 if (sscanf(argv
[1], "%lu", &i
) <= 0)
618 return -E_COMMAND_SYNTAX
;
619 mutex_lock(mmd_mutex
);
620 ret
= -E_NO_AUDIO_FILE
;
621 if (!mmd
->afd
.afhi
.chunks_total
)
625 PARA_INFO_LOG("jumping to %lu%%\n", i
);
626 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
627 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
628 mmd
->chunks_sent
, mmd
->offset
);
629 mmd
->new_vss_status_flags
|= VSS_REPOS
;
630 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
634 mutex_unlock(mmd_mutex
);
639 * check if perms are sufficient to exec a command having perms cmd_perms.
640 * Returns 0 if perms are sufficient, -E_PERM otherwise.
642 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
644 PARA_DEBUG_LOG("checking permissions\n");
645 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
649 * Parse first string from *cmd and lookup in table of valid commands.
650 * On error, NULL is returned.
652 static struct server_command
*parse_cmd(const char *cmdstr
)
657 sscanf(cmdstr
, "%200s%n", buf
, &n
);
661 return get_cmd_ptr(buf
, NULL
);
664 static int read_command(struct stream_cipher_context
*scc
, char **result
)
668 char *command
= NULL
;
674 ret
= sc_recv_buffer(scc
, buf
, sizeof(buf
));
680 ret
= -E_COMMAND_SYNTAX
;
681 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
683 command
= para_strcat(command
, buf
);
684 p
= strstr(command
, EOC_MSG
);
690 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
700 static void reset_signals(void)
702 para_sigaction(SIGCHLD
, SIG_IGN
);
703 para_sigaction(SIGINT
, SIG_DFL
);
704 para_sigaction(SIGTERM
, SIG_DFL
);
705 para_sigaction(SIGHUP
, SIG_DFL
);
709 * Perform user authentication and execute a command.
711 * \param fd The file descriptor to send output to.
712 * \param peername Identifies the connecting peer.
714 * Whenever para_server accepts an incoming tcp connection on
715 * the port it listens on, it forks and the resulting child
716 * calls this function.
718 * An RSA-based challenge/response is used to authenticate
719 * the peer. It that authentication succeeds, a random
720 * session key is generated and sent back to the peer,
721 * encrypted with its RSA public key. From this point on,
722 * all transfers are crypted with this session key.
724 * Next it is checked if the peer supplied a valid server command or a command
725 * for the audio file selector. If yes, and if the user has sufficient
726 * permissions to execute that command, the function calls the corresponding
727 * command handler which does argument checking and further processing.
729 * In order to cope with a DOS attacks, a timeout is set up
730 * which terminates the function if the connection was not
731 * authenticated when the timeout expires.
733 * \sa alarm(2), crypt.c, crypt.h
735 __noreturn
void handle_connect(int fd
, const char *peername
)
739 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * SESSION_KEY_LEN
];
740 unsigned char challenge_hash
[HASH_SIZE
];
742 struct server_command
*cmd
= NULL
;
744 char *p
, *command
= NULL
;
746 struct stream_cipher_context scc
= {.fd
= fd
};
749 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
750 ret
= mark_fd_blocking(fd
);
753 /* send Welcome message */
754 ret
= send_va_buffer(fd
, "This is para_server, version "
755 PACKAGE_VERSION
".\n" );
758 /* recv auth request line */
759 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
763 ret
= -E_AUTH_REQUEST
;
767 ret
= -E_AUTH_REQUEST
;
768 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
770 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
771 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
775 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
776 ret
= pub_encrypt(u
->pubkey
, rand_buf
, sizeof(rand_buf
),
777 (unsigned char *)buf
);
783 * We don't want to reveal our user names, so we send a
784 * challenge to the client even if the user does not exist, and
785 * fail the authentication later.
788 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
790 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
791 CHALLENGE_SIZE
, numbytes
);
792 ret
= send_bin_buffer(fd
, buf
, numbytes
);
795 /* recv challenge response */
796 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
800 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret
);
805 * The correct response is the hash of the first CHALLENGE_SIZE bytes
806 * of the random data.
809 if (numbytes
!= HASH_SIZE
)
811 hash_function((char *)rand_buf
, CHALLENGE_SIZE
, challenge_hash
);
812 if (memcmp(challenge_hash
, buf
, HASH_SIZE
))
814 /* auth successful */
816 PARA_INFO_LOG("good auth for %s\n", u
->name
);
817 /* init stream cipher keys with the second part of the random buffer */
818 scc
.recv
= sc_new(rand_buf
+ CHALLENGE_SIZE
, SESSION_KEY_LEN
);
819 scc
.send
= sc_new(rand_buf
+ CHALLENGE_SIZE
+ SESSION_KEY_LEN
, SESSION_KEY_LEN
);
820 ret
= sc_send_buffer(&scc
, PROCEED_MSG
);
823 ret
= read_command(&scc
, &command
);
824 if (ret
== -E_COMMAND_SYNTAX
)
829 cmd
= parse_cmd(command
);
832 /* valid command, check permissions */
833 ret
= check_perms(u
->perms
, cmd
);
836 /* valid command and sufficient perms */
837 ret
= create_argv(command
, "\n", &argv
);
841 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
843 ret
= cmd
->handler(&scc
, argc
, argv
);
845 mutex_lock(mmd_mutex
);
847 mutex_unlock(mmd_mutex
);
851 sc_send_va_buffer(&scc
, "%s\n", para_strerror(-ret
));
853 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
858 mutex_lock(mmd_mutex
);
859 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
861 mmd
->active_connections
--;
862 mutex_unlock(mmd_mutex
);
863 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);