2 * Copyright (C) 1997-2009 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"
30 #include "user_list.h"
31 #include "server_command_list.h"
32 #include "afs_command_list.h"
36 /** Commands including options must be shorter than this. */
37 #define MAX_COMMAND_LEN 32768
39 static RC4_KEY rc4_recv_key
;
40 static RC4_KEY rc4_send_key
;
41 static unsigned char rc4_buf
[2 * RC4_KEY_LEN
];
44 extern struct misc_meta_data
*mmd
;
45 extern struct sender senders
[];
47 static void dummy(__a_unused
int s
)
51 static void mmd_dup(struct misc_meta_data
*new_mmd
)
53 mutex_lock(mmd_mutex
);
55 mutex_unlock(mmd_mutex
);
59 * Compute human readable string containing vss status for given integer value.
61 * We don't want to use vss_playing() and friends here because we take a
62 * snapshot of the mmd struct and use the copy for computing the state of the
63 * vss. If the real data were used, we would take the mmd lock for a rather
64 * long time or risk to get an inconsistent view.
66 static char *vss_status_tohuman(unsigned int flags
)
68 if (flags
& VSS_PLAYING
)
69 return para_strdup("playing");
71 return para_strdup("stopped");
72 return para_strdup("paused");
76 * return human readable permission string. Never returns NULL.
78 static char *cmd_perms_itohuman(unsigned int perms
)
80 char *msg
= para_malloc(5 * sizeof(char));
82 msg
[0] = perms
& AFS_READ
? 'a' : '-';
83 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
84 msg
[2] = perms
& VSS_READ
? 'v' : '-';
85 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
93 static char *vss_get_status_flags(unsigned int flags
)
95 char *msg
= para_malloc(5 * sizeof(char));
97 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
98 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
99 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
100 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
105 static char *get_status(struct misc_meta_data
*nmmd
)
107 char *ret
, mtime
[30] = "";
108 char *status
, *flags
; /* vss status info */
109 char *ut
= uptime_str();
110 long offset
= (nmmd
->offset
+ 500) / 1000;
111 struct timeval current_time
;
114 /* report real status */
115 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
116 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
117 if (nmmd
->size
) { /* parent currently has an audio file open */
118 localtime_r(&nmmd
->mtime
, &mtime_tm
);
119 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
121 gettimeofday(¤t_time
, NULL
);
123 "%s: %zu\n" /* file size */
124 "%s: %s\n" /* mtime */
125 "%s: %s\n" /* status */
126 "%s: %s\n" /* status flags */
127 "%s: %li\n" /* offset */
128 "%s: %s\n" /* afs mode */
129 "%s: %lu.%lu\n" /* stream start */
130 "%s: %lu.%lu\n" /* current server time */
131 "%s", /* afs status info */
132 status_item_list
[SI_FILE_SIZE
], nmmd
->size
/ 1024,
133 status_item_list
[SI_MTIME
], mtime
,
134 status_item_list
[SI_STATUS
], status
,
135 status_item_list
[SI_STATUS_FLAGS
], flags
,
137 status_item_list
[SI_OFFSET
], offset
,
138 status_item_list
[SI_AFS_MODE
], mmd
->afs_mode_string
,
140 status_item_list
[SI_STREAM_START
],
141 (long unsigned)nmmd
->stream_start
.tv_sec
,
142 (long unsigned)nmmd
->stream_start
.tv_usec
,
143 status_item_list
[SI_CURRENT_TIME
],
144 (long unsigned)current_time
.tv_sec
,
145 (long unsigned)current_time
.tv_usec
,
147 nmmd
->afd
.verbose_ls_output
156 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
159 /* this has to match sender.h */
160 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
162 scd
->sender_num
= -1;
164 return -E_COMMAND_SYNTAX
;
165 for (i
= 0; senders
[i
].name
; i
++)
166 if (!strcmp(senders
[i
].name
, argv
[1]))
168 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
169 if (!senders
[i
].name
)
170 return -E_COMMAND_SYNTAX
;
172 for (i
= 0; subcmds
[i
]; i
++)
173 if (!strcmp(subcmds
[i
], argv
[2]))
176 return -E_COMMAND_SYNTAX
;
178 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
179 return -E_SENDER_CMD
;
180 switch (scd
->cmd_num
) {
184 return -E_COMMAND_SYNTAX
;
188 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
189 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
190 return -E_COMMAND_SYNTAX
;
195 return -E_COMMAND_SYNTAX
;
196 return parse_fec_url(argv
[3], scd
);
198 return -E_COMMAND_SYNTAX
;
203 int com_sender(int fd
, int argc
, char * const * argv
)
206 struct sender_command_data scd
;
210 for (i
= 0; senders
[i
].name
; i
++) {
211 char *tmp
= make_message("%s%s\n",
212 msg
? msg
: "", senders
[i
].name
);
216 ret
= send_buffer(fd
, msg
);
220 ret
= check_sender_args(argc
, argv
, &scd
);
223 if (scd
.sender_num
< 0)
225 msg
= senders
[scd
.sender_num
].help();
226 ret
= send_buffer(fd
, msg
);
230 for (i
= 0; i
< 10; i
++) {
231 mutex_lock(mmd_mutex
);
232 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
233 mutex_unlock(mmd_mutex
);
237 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
238 mutex_unlock(mmd_mutex
);
241 return (i
< 10)? 1 : -E_LOCK
;
245 int com_si(int fd
, int argc
, __a_unused
char * const * argv
)
249 char *sender_info
= NULL
, *sender_list
= NULL
;
252 return -E_COMMAND_SYNTAX
;
253 mutex_lock(mmd_mutex
);
254 for (i
= 0; senders
[i
].name
; i
++) {
255 char *info
= senders
[i
].info();
256 sender_info
= para_strcat(sender_info
, info
);
258 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
259 sender_list
= para_strcat(sender_list
, " ");
262 ret
= send_va_buffer(fd
, "up: %s\nplayed: %u\n"
265 "connections (active/accepted/total): %u/%u/%u\n"
266 "current loglevel: %s\n"
267 "supported audio formats: %s\n"
268 "supported senders: %s\n"
273 mmd
->active_connections
,
277 supported_audio_formats(),
281 mutex_unlock(mmd_mutex
);
289 int com_version(int fd
, int argc
, __a_unused
char * const * argv
)
292 return -E_COMMAND_SYNTAX
;
293 return send_buffer(fd
, VERSION_TEXT("server")
294 "built: " BUILD_DATE
"\n"
295 UNAME_RS
", " CC_VERSION
"\n"
300 int com_stat(int fd
, int argc
, char * const * argv
)
302 int ret
, num
= 0;/* status will be printed that many
303 * times. num <= 0 means: print forever
305 struct misc_meta_data tmp
, *nmmd
= &tmp
;
308 para_sigaction(SIGUSR1
, dummy
);
311 return -E_COMMAND_SYNTAX
;
313 ret
= para_atoi32(argv
[1], &num
);
320 s
= get_status(nmmd
);
321 ret
= send_buffer(fd
, s
);
326 if (num
> 0 && !--num
)
330 return -E_SERVER_CRASH
;
336 static int send_list_of_commands(int fd
, struct server_command
*cmd
,
341 for (i
= 1; cmd
->name
; cmd
++, i
++) {
342 char *perms
= cmd_perms_itohuman(cmd
->perms
);
343 ret
= send_va_buffer(fd
, "%s\t%s\t%s\t%s\n", cmd
->name
,
354 /* returns string that must be freed by the caller */
355 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
357 struct server_command
*cmd
;
359 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
360 if (!strcmp(cmd
->name
, name
)) {
362 *handler
= para_strdup("server"); /* server commands */
365 /* not found, look for commands supported by afs */
366 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
367 if (!strcmp(cmd
->name
, name
)) {
369 *handler
= para_strdup("afs");
376 int com_help(int fd
, int argc
, char * const * argv
)
378 struct server_command
*cmd
;
379 char *perms
, *handler
;
383 /* no argument given, print list of commands */
384 if ((ret
= send_list_of_commands(fd
, server_cmds
, "server")) < 0)
386 return send_list_of_commands(fd
, afs_cmds
, "afs");
388 /* argument given for help */
389 cmd
= get_cmd_ptr(argv
[1], &handler
);
394 perms
= cmd_perms_itohuman(cmd
->perms
);
395 ret
= send_va_buffer(fd
,
414 int com_hup(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
417 return -E_COMMAND_SYNTAX
;
418 kill(getppid(), SIGHUP
);
423 int com_term(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
426 return -E_COMMAND_SYNTAX
;
427 kill(getppid(), SIGTERM
);
431 int com_play(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
434 return -E_COMMAND_SYNTAX
;
435 mutex_lock(mmd_mutex
);
436 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
437 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
438 mutex_unlock(mmd_mutex
);
444 int com_stop(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
447 return -E_COMMAND_SYNTAX
;
448 mutex_lock(mmd_mutex
);
449 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
450 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
451 mmd
->new_vss_status_flags
|= VSS_NEXT
;
452 mutex_unlock(mmd_mutex
);
457 int com_pause(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
460 return -E_COMMAND_SYNTAX
;
461 mutex_lock(mmd_mutex
);
462 if (!vss_paused() && !vss_stopped()) {
464 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
465 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
467 mutex_unlock(mmd_mutex
);
472 int com_next(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
475 return -E_COMMAND_SYNTAX
;
476 mutex_lock(mmd_mutex
);
478 mmd
->new_vss_status_flags
|= VSS_NEXT
;
479 mutex_unlock(mmd_mutex
);
484 int com_nomore(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
487 return -E_COMMAND_SYNTAX
;
488 mutex_lock(mmd_mutex
);
489 if (vss_playing() || vss_paused())
490 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
491 mutex_unlock(mmd_mutex
);
496 int com_ff(__a_unused
int fd
, int argc
, char * const * argv
)
499 int ret
, backwards
= 0;
504 return -E_COMMAND_SYNTAX
;
505 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
506 return -E_COMMAND_SYNTAX
;
507 if (ret
> 1 && c
== '-')
508 backwards
= 1; /* jmp backwards */
509 mutex_lock(mmd_mutex
);
510 ret
= -E_NO_AUDIO_FILE
;
511 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
513 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
515 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
517 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
520 if (promille
> 1000) {
521 mmd
->new_vss_status_flags
|= VSS_NEXT
;
524 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
525 mmd
->new_vss_status_flags
|= VSS_REPOS
;
526 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
530 mutex_unlock(mmd_mutex
);
535 int com_jmp(__a_unused
int fd
, int argc
, char * const * argv
)
541 return -E_COMMAND_SYNTAX
;
542 if (sscanf(argv
[1], "%lu", &i
) <= 0)
543 return -E_COMMAND_SYNTAX
;
544 mutex_lock(mmd_mutex
);
545 ret
= -E_NO_AUDIO_FILE
;
546 if (!mmd
->afd
.afhi
.chunks_total
)
550 PARA_INFO_LOG("jumping to %lu%%\n", i
);
551 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
552 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
553 mmd
->chunks_sent
, mmd
->offset
);
554 mmd
->new_vss_status_flags
|= VSS_REPOS
;
555 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
559 mutex_unlock(mmd_mutex
);
564 * check if perms are sufficient to exec a command having perms cmd_perms.
565 * Returns 0 if perms are sufficient, -E_PERM otherwise.
567 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
569 PARA_DEBUG_LOG("checking permissions\n");
570 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
574 * Parse first string from *cmd and lookup in table of valid commands.
575 * On error, NULL is returned.
577 static struct server_command
*parse_cmd(const char *cmdstr
)
582 sscanf(cmdstr
, "%200s%n", buf
, &n
);
586 return get_cmd_ptr(buf
, NULL
);
589 static void init_rc4_keys(void)
593 for (i
= 0; i
< 2 * RC4_KEY_LEN
; i
++)
594 rc4_buf
[i
] = para_random(256);
595 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
596 (unsigned char) rc4_buf
[0],
597 (unsigned char) rc4_buf
[RC4_KEY_LEN
]);
598 RC4_set_key(&rc4_recv_key
, RC4_KEY_LEN
, rc4_buf
);
599 RC4_set_key(&rc4_send_key
, RC4_KEY_LEN
, rc4_buf
+ RC4_KEY_LEN
);
602 static void rc4_recv(unsigned long len
, const unsigned char *indata
,
603 unsigned char *outdata
, __a_unused
void *private_data
)
605 RC4(&rc4_recv_key
, len
, indata
, outdata
);
608 static void rc4_send(unsigned long len
, const unsigned char *indata
,
609 unsigned char *outdata
, __a_unused
void *private_data
)
611 RC4(&rc4_send_key
, len
, indata
, outdata
);
614 static int read_command(int fd
, char **result
)
618 char *command
= NULL
;
624 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
630 ret
= -E_COMMAND_SYNTAX
;
631 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
633 command
= para_strcat(command
, buf
);
634 p
= strstr(command
, EOC_MSG
);
640 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
650 static void reset_signals(void)
652 para_sigaction(SIGCHLD
, SIG_IGN
);
653 para_sigaction(SIGINT
, SIG_DFL
);
654 para_sigaction(SIGTERM
, SIG_DFL
);
655 para_sigaction(SIGHUP
, SIG_DFL
);
659 * Perform user authentication and execute a command.
661 * \param fd The file descriptor to send output to.
662 * \param peername Identifies the connecting peer.
664 * Whenever para_server accepts an incoming tcp connection on
665 * the port it listens on, it forks and the resulting child
666 * calls this function.
668 * An RSA-based challenge/response is used to authenticate
669 * the peer. It that authentication succeeds, a random RC4
670 * session key is generated and sent back to the peer,
671 * encrypted with its RSA public key. From this point on,
672 * all transfers are crypted with this session key.
674 * Next it is checked if the peer supplied a valid server command or a command
675 * for the audio file selector. If yes, and if the user has sufficient
676 * permissions to execute that command, the function calls the corresponding
677 * command handler which does argument checking and further processing.
679 * In order to cope with a DOS attacks, a timeout is set up
680 * which terminates the function if the connection was not
681 * authenticated when the timeout expires.
683 * \sa alarm(2), rc4(3), crypt.c, crypt.h
685 __noreturn
void handle_connect(int fd
, const char *peername
)
687 int ret
, argc
, use_rc4
= 0;
689 unsigned char crypt_buf
[MAXLINE
];
691 struct server_command
*cmd
= NULL
;
692 long unsigned challenge_nr
, chall_response
;
694 char *p
, *command
= NULL
;
698 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
699 ret
= mark_fd_blocking(fd
);
702 challenge_nr
= random();
703 /* send Welcome message */
704 ret
= send_va_buffer(fd
, "This is para_server, version "
705 PACKAGE_VERSION
".\n" );
708 /* recv auth request line */
709 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
718 if (strncmp(buf
, "auth ", 5))
721 if (numbytes
< 9 || strncmp(buf
, "auth rc4 ", 9))
722 p
= buf
+ 5; /* client version < 0.2.6 */
724 p
= buf
+ 9; /* client version >= 0.2.6 */
727 PARA_DEBUG_LOG("received %s request for user %s\n",
728 use_rc4
? "rc4" : "auth", p
);
733 ret
= para_encrypt_challenge(u
->rsa
, challenge_nr
, crypt_buf
);
737 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes
);
738 /* We can't use send_buffer here since buf may contain null bytes */
739 ret
= send_bin_buffer(fd
,(char *) crypt_buf
, numbytes
);
742 /* recv decrypted number */
743 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
750 if (sscanf(buf
, CHALLENGE_RESPONSE_MSG
"%lu", &chall_response
) < 1
751 || chall_response
!= challenge_nr
)
753 /* auth successful, send 'Proceed' message */
754 PARA_INFO_LOG("good auth for %s (%lu)\n", u
->name
, challenge_nr
);
755 sprintf(buf
, "%s", PROCEED_MSG
);
758 ret
= para_encrypt_buffer(u
->rsa
, rc4_buf
, 2 * RC4_KEY_LEN
,
759 (unsigned char *)buf
+ PROCEED_MSG_LEN
+ 1);
762 numbytes
= ret
+ strlen(PROCEED_MSG
) + 1;
764 numbytes
= strlen(buf
);
765 ret
= send_bin_buffer(fd
, buf
, numbytes
);
769 enable_crypt(fd
, rc4_recv
, rc4_send
, NULL
);
770 ret
= read_command(fd
, &command
);
771 if (ret
== -E_COMMAND_SYNTAX
)
776 cmd
= parse_cmd(command
);
779 /* valid command, check permissions */
780 ret
= check_perms(u
->perms
, cmd
);
783 /* valid command and sufficient perms */
785 argc
= split_args(command
, &argv
, "\n");
786 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
788 ret
= cmd
->handler(fd
, argc
, argv
);
789 mutex_lock(mmd_mutex
);
791 mutex_unlock(mmd_mutex
);
795 send_va_buffer(fd
, "%s\n", para_strerror(-ret
));
797 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
801 mutex_lock(mmd_mutex
);
802 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
804 mmd
->active_connections
--;
805 mutex_unlock(mmd_mutex
);
806 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);