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>
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
[];
45 static void dummy(__a_unused
int s
)
49 static void mmd_dup(struct misc_meta_data
*new_mmd
)
51 mutex_lock(mmd_mutex
);
53 mutex_unlock(mmd_mutex
);
57 * Compute human readable string containing vss status for given integer value.
59 * We don't want to use vss_playing() and friends here because we take a
60 * snapshot of the mmd struct and use the copy for computing the state of the
61 * vss. If the real data were used, we would take the mmd lock for a rather
62 * long time or risk to get an inconsistent view.
64 static char *vss_status_tohuman(unsigned int flags
)
66 if (flags
& VSS_PLAYING
)
67 return para_strdup("playing");
69 return para_strdup("stopped");
70 return para_strdup("paused");
74 * return human readable permission string. Never returns NULL.
76 static char *cmd_perms_itohuman(unsigned int perms
)
78 char *msg
= para_malloc(5 * sizeof(char));
80 msg
[0] = perms
& AFS_READ
? 'a' : '-';
81 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
82 msg
[2] = perms
& VSS_READ
? 'v' : '-';
83 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
91 static char *vss_get_status_flags(unsigned int flags
)
93 char *msg
= para_malloc(5 * sizeof(char));
95 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
96 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
97 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
98 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
103 static char *get_status(struct misc_meta_data
*nmmd
)
105 char *ret
, mtime
[30] = "";
106 char *status
, *flags
; /* vss status info */
107 char *ut
= uptime_str();
108 long offset
= (nmmd
->offset
+ 500) / 1000;
109 struct timeval current_time
;
112 /* report real status */
113 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
114 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
115 if (nmmd
->size
) { /* parent currently has an audio file open */
116 localtime_r(&nmmd
->mtime
, &mtime_tm
);
117 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
119 gettimeofday(¤t_time
, NULL
);
121 "%s: %zu\n" /* file size */
122 "%s: %s\n" /* mtime */
123 "%s: %s\n" /* status */
124 "%s: %s\n" /* status flags */
125 "%s: %li\n" /* offset */
126 "%s: %s\n" /* afs mode */
127 "%s: %lu.%lu\n" /* stream start */
128 "%s: %lu.%lu\n" /* current server time */
129 "%s", /* afs status info */
130 status_item_list
[SI_FILE_SIZE
], nmmd
->size
/ 1024,
131 status_item_list
[SI_MTIME
], mtime
,
132 status_item_list
[SI_STATUS
], status
,
133 status_item_list
[SI_STATUS_FLAGS
], flags
,
135 status_item_list
[SI_OFFSET
], offset
,
136 status_item_list
[SI_AFS_MODE
], mmd
->afs_mode_string
,
138 status_item_list
[SI_STREAM_START
],
139 (long unsigned)nmmd
->stream_start
.tv_sec
,
140 (long unsigned)nmmd
->stream_start
.tv_usec
,
141 status_item_list
[SI_CURRENT_TIME
],
142 (long unsigned)current_time
.tv_sec
,
143 (long unsigned)current_time
.tv_usec
,
145 nmmd
->afd
.verbose_ls_output
154 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
157 /* this has to match sender.h */
158 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
160 scd
->sender_num
= -1;
162 return -E_COMMAND_SYNTAX
;
163 for (i
= 0; senders
[i
].name
; i
++)
164 if (!strcmp(senders
[i
].name
, argv
[1]))
166 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
167 if (!senders
[i
].name
)
168 return -E_COMMAND_SYNTAX
;
170 for (i
= 0; subcmds
[i
]; i
++)
171 if (!strcmp(subcmds
[i
], argv
[2]))
174 return -E_COMMAND_SYNTAX
;
176 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
177 return -E_SENDER_CMD
;
178 switch (scd
->cmd_num
) {
182 return -E_COMMAND_SYNTAX
;
186 if (argc
!= 4 && argc
!= 5)
187 return -E_COMMAND_SYNTAX
;
188 if (!is_valid_ipv4_address(argv
[3]))
189 return -E_COMMAND_SYNTAX
;
192 scd
->netmask
= atoi(argv
[4]);
193 if (scd
->netmask
< 0 || scd
->netmask
> 32)
194 return -E_COMMAND_SYNTAX
;
196 strncpy(scd
->host
, argv
[3], sizeof(scd
->host
));
201 return -E_COMMAND_SYNTAX
;
202 return parse_fec_url(argv
[3], scd
);
204 return -E_COMMAND_SYNTAX
;
209 int com_sender(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
212 struct sender_command_data scd
;
216 for (i
= 0; senders
[i
].name
; i
++) {
217 char *tmp
= make_message("%s%s\n",
218 msg
? msg
: "", senders
[i
].name
);
222 ret
= rc4_send_buffer(rc4c
, msg
);
226 ret
= check_sender_args(argc
, argv
, &scd
);
229 if (scd
.sender_num
< 0)
231 msg
= senders
[scd
.sender_num
].help();
232 ret
= rc4_send_buffer(rc4c
, msg
);
236 for (i
= 0; i
< 10; i
++) {
237 mutex_lock(mmd_mutex
);
238 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
239 mutex_unlock(mmd_mutex
);
243 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
244 mutex_unlock(mmd_mutex
);
247 return (i
< 10)? 1 : -E_LOCK
;
251 int com_si(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
255 char *sender_info
= NULL
, *sender_list
= NULL
;
258 return -E_COMMAND_SYNTAX
;
259 mutex_lock(mmd_mutex
);
260 for (i
= 0; senders
[i
].name
; i
++) {
261 char *info
= senders
[i
].info();
262 sender_info
= para_strcat(sender_info
, info
);
264 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
265 sender_list
= para_strcat(sender_list
, " ");
268 ret
= rc4_send_va_buffer(rc4c
, "up: %s\nplayed: %u\n"
271 "connections (active/accepted/total): %u/%u/%u\n"
272 "current loglevel: %s\n"
273 "supported audio formats: %s\n"
274 "supported senders: %s\n"
279 mmd
->active_connections
,
283 supported_audio_formats(),
287 mutex_unlock(mmd_mutex
);
295 int com_version(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
298 return -E_COMMAND_SYNTAX
;
299 return rc4_send_buffer(rc4c
, VERSION_TEXT("server")
300 "built: " BUILD_DATE
"\n"
301 UNAME_RS
", " CC_VERSION
"\n"
306 int com_stat(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
308 int ret
, num
= 0;/* status will be printed that many
309 * times. num <= 0 means: print forever
311 struct misc_meta_data tmp
, *nmmd
= &tmp
;
314 para_sigaction(SIGUSR1
, dummy
);
321 s
= get_status(nmmd
);
322 ret
= rc4_send_buffer(rc4c
, s
);
327 if (num
> 0 && !--num
)
331 return -E_SERVER_CRASH
;
337 static int send_list_of_commands(struct rc4_context
*rc4c
, struct server_command
*cmd
,
342 for (i
= 1; cmd
->name
; cmd
++, i
++) {
343 char *perms
= cmd_perms_itohuman(cmd
->perms
);
344 ret
= rc4_send_va_buffer(rc4c
, "%s\t%s\t%s\t%s\n", cmd
->name
,
355 /* returns string that must be freed by the caller */
356 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
358 struct server_command
*cmd
;
360 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
361 if (!strcmp(cmd
->name
, name
)) {
363 *handler
= para_strdup("server"); /* server commands */
366 /* not found, look for commands supported by afs */
367 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
368 if (!strcmp(cmd
->name
, name
)) {
370 *handler
= para_strdup("afs");
377 int com_help(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
379 struct server_command
*cmd
;
380 char *perms
, *handler
;
384 /* no argument given, print list of commands */
385 if ((ret
= send_list_of_commands(rc4c
, server_cmds
, "server")) < 0)
387 return send_list_of_commands(rc4c
, afs_cmds
, "afs");
389 /* argument given for help */
390 cmd
= get_cmd_ptr(argv
[1], &handler
);
395 perms
= cmd_perms_itohuman(cmd
->perms
);
396 ret
= rc4_send_va_buffer(rc4c
,
415 int com_hup(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
418 return -E_COMMAND_SYNTAX
;
419 kill(getppid(), SIGHUP
);
424 int com_term(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
427 return -E_COMMAND_SYNTAX
;
428 kill(getppid(), SIGTERM
);
432 int com_play(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
435 return -E_COMMAND_SYNTAX
;
436 mutex_lock(mmd_mutex
);
437 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
438 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
439 mutex_unlock(mmd_mutex
);
445 int com_stop(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
448 return -E_COMMAND_SYNTAX
;
449 mutex_lock(mmd_mutex
);
450 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
451 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
452 mmd
->new_vss_status_flags
|= VSS_NEXT
;
453 mutex_unlock(mmd_mutex
);
458 int com_pause(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
461 return -E_COMMAND_SYNTAX
;
462 mutex_lock(mmd_mutex
);
463 if (!vss_paused() && !vss_stopped()) {
465 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
466 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
468 mutex_unlock(mmd_mutex
);
473 int com_next(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
476 return -E_COMMAND_SYNTAX
;
477 mutex_lock(mmd_mutex
);
479 mmd
->new_vss_status_flags
|= VSS_NEXT
;
480 mutex_unlock(mmd_mutex
);
485 int com_nomore(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
488 return -E_COMMAND_SYNTAX
;
489 mutex_lock(mmd_mutex
);
490 if (vss_playing() || vss_paused())
491 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
492 mutex_unlock(mmd_mutex
);
497 int com_ff(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
500 int ret
, backwards
= 0;
505 return -E_COMMAND_SYNTAX
;
506 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
507 return -E_COMMAND_SYNTAX
;
508 if (ret
> 1 && c
== '-')
509 backwards
= 1; /* jmp backwards */
510 mutex_lock(mmd_mutex
);
511 ret
= -E_NO_AUDIO_FILE
;
512 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
514 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
516 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
518 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
521 if (promille
> 1000) {
522 mmd
->new_vss_status_flags
|= VSS_NEXT
;
525 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
526 mmd
->new_vss_status_flags
|= VSS_REPOS
;
527 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
531 mutex_unlock(mmd_mutex
);
536 int com_jmp(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
542 return -E_COMMAND_SYNTAX
;
543 if (sscanf(argv
[1], "%lu", &i
) <= 0)
544 return -E_COMMAND_SYNTAX
;
545 mutex_lock(mmd_mutex
);
546 ret
= -E_NO_AUDIO_FILE
;
547 if (!mmd
->afd
.afhi
.chunks_total
)
551 PARA_INFO_LOG("jumping to %lu%%\n", i
);
552 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
553 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
554 mmd
->chunks_sent
, mmd
->offset
);
555 mmd
->new_vss_status_flags
|= VSS_REPOS
;
556 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
560 mutex_unlock(mmd_mutex
);
565 * check if perms are sufficient to exec a command having perms cmd_perms.
566 * Returns 0 if perms are sufficient, -E_PERM otherwise.
568 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
570 PARA_DEBUG_LOG("checking permissions\n");
571 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
575 * Parse first string from *cmd and lookup in table of valid commands.
576 * On error, NULL is returned.
578 static struct server_command
*parse_cmd(const char *cmdstr
)
583 sscanf(cmdstr
, "%200s%n", buf
, &n
);
587 return get_cmd_ptr(buf
, NULL
);
590 static int read_command(struct rc4_context
*rc4c
, char **result
)
594 char *command
= NULL
;
600 ret
= rc4_recv_buffer(rc4c
, buf
, sizeof(buf
));
606 ret
= -E_COMMAND_SYNTAX
;
607 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
609 command
= para_strcat(command
, buf
);
610 p
= strstr(command
, EOC_MSG
);
616 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
626 static void reset_signals(void)
628 para_sigaction(SIGCHLD
, SIG_IGN
);
629 para_sigaction(SIGINT
, SIG_DFL
);
630 para_sigaction(SIGTERM
, SIG_DFL
);
631 para_sigaction(SIGHUP
, SIG_DFL
);
635 * Perform user authentication and execute a command.
637 * \param fd The file descriptor to send output to.
638 * \param peername Identifies the connecting peer.
640 * Whenever para_server accepts an incoming tcp connection on
641 * the port it listens on, it forks and the resulting child
642 * calls this function.
644 * An RSA-based challenge/response is used to authenticate
645 * the peer. It that authentication succeeds, a random RC4
646 * session key is generated and sent back to the peer,
647 * encrypted with its RSA public key. From this point on,
648 * all transfers are crypted with this session key.
650 * Next it is checked if the peer supplied a valid server command or a command
651 * for the audio file selector. If yes, and if the user has sufficient
652 * permissions to execute that command, the function calls the corresponding
653 * command handler which does argument checking and further processing.
655 * In order to cope with a DOS attacks, a timeout is set up
656 * which terminates the function if the connection was not
657 * authenticated when the timeout expires.
659 * \sa alarm(2), rc4(3), crypt.c, crypt.h
661 __noreturn
void handle_connect(int fd
, const char *peername
)
665 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * RC4_KEY_LEN
];
666 unsigned char challenge_sha1
[HASH_SIZE
];
668 struct server_command
*cmd
= NULL
;
670 char *p
, *command
= NULL
;
672 struct rc4_context rc4c
= {.fd
= fd
};
675 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
676 ret
= mark_fd_blocking(fd
);
679 /* send Welcome message */
680 ret
= send_va_buffer(fd
, "This is para_server, version "
681 PACKAGE_VERSION
".\n" );
684 /* recv auth request line */
685 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
689 ret
= -E_AUTH_REQUEST
;
693 ret
= -E_AUTH_REQUEST
;
694 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
696 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
697 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
701 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
702 ret
= para_encrypt_buffer(u
->rsa
, rand_buf
, sizeof(rand_buf
),
703 (unsigned char *)buf
);
709 * We don't want to reveal our user names, so we send a
710 * challenge to the client even if the user does not exist, and
711 * fail the authentication later.
714 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
716 PARA_DEBUG_LOG("sending %zu byte challenge + rc4 keys (%u bytes)\n",
717 CHALLENGE_SIZE
, numbytes
);
718 ret
= send_bin_buffer(fd
, buf
, numbytes
);
721 /* recv challenge response */
722 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
726 PARA_DEBUG_LOG("received %zu bytes challenge response\n", ret
);
731 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
732 * of the random data.
735 if (numbytes
!= HASH_SIZE
)
737 sha1_hash((char *)rand_buf
, CHALLENGE_SIZE
, challenge_sha1
);
738 if (memcmp(challenge_sha1
, buf
, HASH_SIZE
))
740 /* auth successful */
742 PARA_INFO_LOG("good auth for %s\n", u
->name
);
743 /* init rc4 keys with the second part of the random buffer */
744 RC4_set_key(&rc4c
.recv_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
);
745 RC4_set_key(&rc4c
.send_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
747 ret
= rc4_send_buffer(&rc4c
, PROCEED_MSG
);
750 ret
= read_command(&rc4c
, &command
);
751 if (ret
== -E_COMMAND_SYNTAX
)
756 cmd
= parse_cmd(command
);
759 /* valid command, check permissions */
760 ret
= check_perms(u
->perms
, cmd
);
763 /* valid command and sufficient perms */
764 argc
= split_args(command
, &argv
, "\n");
765 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
767 ret
= cmd
->handler(&rc4c
, argc
, argv
);
768 mutex_lock(mmd_mutex
);
770 mutex_unlock(mmd_mutex
);
774 rc4_send_va_buffer(&rc4c
, "%s\n", para_strerror(-ret
));
776 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
780 mutex_lock(mmd_mutex
);
781 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
783 mmd
->active_connections
--;
784 mutex_unlock(mmd_mutex
);
785 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);