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 || parse_cidr(argv
[3], scd
->host
,
187 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
188 return -E_COMMAND_SYNTAX
;
193 return -E_COMMAND_SYNTAX
;
194 return parse_fec_url(argv
[3], scd
);
196 return -E_COMMAND_SYNTAX
;
201 int com_sender(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
204 struct sender_command_data scd
;
208 for (i
= 0; senders
[i
].name
; i
++) {
209 char *tmp
= make_message("%s%s\n",
210 msg
? msg
: "", senders
[i
].name
);
214 ret
= rc4_send_buffer(rc4c
, msg
);
218 ret
= check_sender_args(argc
, argv
, &scd
);
221 if (scd
.sender_num
< 0)
223 msg
= senders
[scd
.sender_num
].help();
224 ret
= rc4_send_buffer(rc4c
, msg
);
228 for (i
= 0; i
< 10; i
++) {
229 mutex_lock(mmd_mutex
);
230 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
231 mutex_unlock(mmd_mutex
);
235 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
236 mutex_unlock(mmd_mutex
);
239 return (i
< 10)? 1 : -E_LOCK
;
243 int com_si(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
247 char *sender_info
= NULL
, *sender_list
= NULL
;
250 return -E_COMMAND_SYNTAX
;
251 mutex_lock(mmd_mutex
);
252 for (i
= 0; senders
[i
].name
; i
++) {
253 char *info
= senders
[i
].info();
254 sender_info
= para_strcat(sender_info
, info
);
256 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
257 sender_list
= para_strcat(sender_list
, " ");
260 ret
= rc4_send_va_buffer(rc4c
, "up: %s\nplayed: %u\n"
263 "connections (active/accepted/total): %u/%u/%u\n"
264 "current loglevel: %s\n"
265 "supported audio formats: %s\n"
266 "supported senders: %s\n"
271 mmd
->active_connections
,
275 supported_audio_formats(),
279 mutex_unlock(mmd_mutex
);
287 int com_version(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
290 return -E_COMMAND_SYNTAX
;
291 return rc4_send_buffer(rc4c
, VERSION_TEXT("server")
292 "built: " BUILD_DATE
"\n"
293 UNAME_RS
", " CC_VERSION
"\n"
298 int com_stat(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
300 int ret
, num
= 0;/* status will be printed that many
301 * times. num <= 0 means: print forever
303 struct misc_meta_data tmp
, *nmmd
= &tmp
;
306 para_sigaction(SIGUSR1
, dummy
);
313 s
= get_status(nmmd
);
314 ret
= rc4_send_buffer(rc4c
, s
);
319 if (num
> 0 && !--num
)
323 return -E_SERVER_CRASH
;
329 static int send_list_of_commands(struct rc4_context
*rc4c
, struct server_command
*cmd
,
334 for (i
= 1; cmd
->name
; cmd
++, i
++) {
335 char *perms
= cmd_perms_itohuman(cmd
->perms
);
336 ret
= rc4_send_va_buffer(rc4c
, "%s\t%s\t%s\t%s\n", cmd
->name
,
347 /* returns string that must be freed by the caller */
348 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
350 struct server_command
*cmd
;
352 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
353 if (!strcmp(cmd
->name
, name
)) {
355 *handler
= para_strdup("server"); /* server commands */
358 /* not found, look for commands supported by afs */
359 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
360 if (!strcmp(cmd
->name
, name
)) {
362 *handler
= para_strdup("afs");
369 int com_help(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
371 struct server_command
*cmd
;
372 char *perms
, *handler
;
376 /* no argument given, print list of commands */
377 if ((ret
= send_list_of_commands(rc4c
, server_cmds
, "server")) < 0)
379 return send_list_of_commands(rc4c
, afs_cmds
, "afs");
381 /* argument given for help */
382 cmd
= get_cmd_ptr(argv
[1], &handler
);
387 perms
= cmd_perms_itohuman(cmd
->perms
);
388 ret
= rc4_send_va_buffer(rc4c
,
407 int com_hup(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
410 return -E_COMMAND_SYNTAX
;
411 kill(getppid(), SIGHUP
);
416 int com_term(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
419 return -E_COMMAND_SYNTAX
;
420 kill(getppid(), SIGTERM
);
424 int com_play(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
427 return -E_COMMAND_SYNTAX
;
428 mutex_lock(mmd_mutex
);
429 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
430 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
431 mutex_unlock(mmd_mutex
);
437 int com_stop(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
440 return -E_COMMAND_SYNTAX
;
441 mutex_lock(mmd_mutex
);
442 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
443 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
444 mmd
->new_vss_status_flags
|= VSS_NEXT
;
445 mutex_unlock(mmd_mutex
);
450 int com_pause(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
453 return -E_COMMAND_SYNTAX
;
454 mutex_lock(mmd_mutex
);
455 if (!vss_paused() && !vss_stopped()) {
457 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
458 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
460 mutex_unlock(mmd_mutex
);
465 int com_next(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
468 return -E_COMMAND_SYNTAX
;
469 mutex_lock(mmd_mutex
);
471 mmd
->new_vss_status_flags
|= VSS_NEXT
;
472 mutex_unlock(mmd_mutex
);
477 int com_nomore(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
480 return -E_COMMAND_SYNTAX
;
481 mutex_lock(mmd_mutex
);
482 if (vss_playing() || vss_paused())
483 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
484 mutex_unlock(mmd_mutex
);
489 int com_ff(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
492 int ret
, backwards
= 0;
497 return -E_COMMAND_SYNTAX
;
498 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
499 return -E_COMMAND_SYNTAX
;
500 if (ret
> 1 && c
== '-')
501 backwards
= 1; /* jmp backwards */
502 mutex_lock(mmd_mutex
);
503 ret
= -E_NO_AUDIO_FILE
;
504 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
506 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
508 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
510 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
513 if (promille
> 1000) {
514 mmd
->new_vss_status_flags
|= VSS_NEXT
;
517 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
518 mmd
->new_vss_status_flags
|= VSS_REPOS
;
519 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
523 mutex_unlock(mmd_mutex
);
528 int com_jmp(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
534 return -E_COMMAND_SYNTAX
;
535 if (sscanf(argv
[1], "%lu", &i
) <= 0)
536 return -E_COMMAND_SYNTAX
;
537 mutex_lock(mmd_mutex
);
538 ret
= -E_NO_AUDIO_FILE
;
539 if (!mmd
->afd
.afhi
.chunks_total
)
543 PARA_INFO_LOG("jumping to %lu%%\n", i
);
544 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
545 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
546 mmd
->chunks_sent
, mmd
->offset
);
547 mmd
->new_vss_status_flags
|= VSS_REPOS
;
548 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
552 mutex_unlock(mmd_mutex
);
557 * check if perms are sufficient to exec a command having perms cmd_perms.
558 * Returns 0 if perms are sufficient, -E_PERM otherwise.
560 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
562 PARA_DEBUG_LOG("checking permissions\n");
563 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
567 * Parse first string from *cmd and lookup in table of valid commands.
568 * On error, NULL is returned.
570 static struct server_command
*parse_cmd(const char *cmdstr
)
575 sscanf(cmdstr
, "%200s%n", buf
, &n
);
579 return get_cmd_ptr(buf
, NULL
);
582 static int read_command(struct rc4_context
*rc4c
, char **result
)
586 char *command
= NULL
;
592 ret
= rc4_recv_buffer(rc4c
, buf
, sizeof(buf
));
598 ret
= -E_COMMAND_SYNTAX
;
599 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
601 command
= para_strcat(command
, buf
);
602 p
= strstr(command
, EOC_MSG
);
608 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
618 static void reset_signals(void)
620 para_sigaction(SIGCHLD
, SIG_IGN
);
621 para_sigaction(SIGINT
, SIG_DFL
);
622 para_sigaction(SIGTERM
, SIG_DFL
);
623 para_sigaction(SIGHUP
, SIG_DFL
);
627 * Perform user authentication and execute a command.
629 * \param fd The file descriptor to send output to.
630 * \param peername Identifies the connecting peer.
632 * Whenever para_server accepts an incoming tcp connection on
633 * the port it listens on, it forks and the resulting child
634 * calls this function.
636 * An RSA-based challenge/response is used to authenticate
637 * the peer. It that authentication succeeds, a random RC4
638 * session key is generated and sent back to the peer,
639 * encrypted with its RSA public key. From this point on,
640 * all transfers are crypted with this session key.
642 * Next it is checked if the peer supplied a valid server command or a command
643 * for the audio file selector. If yes, and if the user has sufficient
644 * permissions to execute that command, the function calls the corresponding
645 * command handler which does argument checking and further processing.
647 * In order to cope with a DOS attacks, a timeout is set up
648 * which terminates the function if the connection was not
649 * authenticated when the timeout expires.
651 * \sa alarm(2), rc4(3), crypt.c, crypt.h
653 __noreturn
void handle_connect(int fd
, const char *peername
)
657 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * RC4_KEY_LEN
];
658 unsigned char challenge_sha1
[HASH_SIZE
];
660 struct server_command
*cmd
= NULL
;
662 char *p
, *command
= NULL
;
664 struct rc4_context rc4c
= {.fd
= fd
};
667 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
668 ret
= mark_fd_blocking(fd
);
671 /* send Welcome message */
672 ret
= send_va_buffer(fd
, "This is para_server, version "
673 PACKAGE_VERSION
".\n" );
676 /* recv auth request line */
677 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
681 ret
= -E_AUTH_REQUEST
;
685 ret
= -E_AUTH_REQUEST
;
686 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
688 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
689 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
693 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
694 ret
= para_encrypt_buffer(u
->rsa
, rand_buf
, sizeof(rand_buf
),
695 (unsigned char *)buf
);
701 * We don't want to reveal our user names, so we send a
702 * challenge to the client even if the user does not exist, and
703 * fail the authentication later.
706 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
708 PARA_DEBUG_LOG("sending %zu byte challenge + rc4 keys (%u bytes)\n",
709 CHALLENGE_SIZE
, numbytes
);
710 ret
= send_bin_buffer(fd
, buf
, numbytes
);
713 /* recv challenge response */
714 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
718 PARA_DEBUG_LOG("received %zu bytes challenge response\n", ret
);
723 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
724 * of the random data.
727 if (numbytes
!= HASH_SIZE
)
729 sha1_hash((char *)rand_buf
, CHALLENGE_SIZE
, challenge_sha1
);
730 if (memcmp(challenge_sha1
, buf
, HASH_SIZE
))
732 /* auth successful */
734 PARA_INFO_LOG("good auth for %s\n", u
->name
);
735 /* init rc4 keys with the second part of the random buffer */
736 RC4_set_key(&rc4c
.recv_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
);
737 RC4_set_key(&rc4c
.send_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
739 ret
= rc4_send_buffer(&rc4c
, PROCEED_MSG
);
742 ret
= read_command(&rc4c
, &command
);
743 if (ret
== -E_COMMAND_SYNTAX
)
748 cmd
= parse_cmd(command
);
751 /* valid command, check permissions */
752 ret
= check_perms(u
->perms
, cmd
);
755 /* valid command and sufficient perms */
756 argc
= split_args(command
, &argv
, "\n");
757 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
759 ret
= cmd
->handler(&rc4c
, argc
, argv
);
760 mutex_lock(mmd_mutex
);
762 mutex_unlock(mmd_mutex
);
766 rc4_send_va_buffer(&rc4c
, "%s\n", para_strerror(-ret
));
768 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
772 mutex_lock(mmd_mutex
);
773 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
775 mmd
->active_connections
--;
776 mutex_unlock(mmd_mutex
);
777 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);