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. */
12 #include <sys/types.h>
14 #include <openssl/rc4.h>
21 #include "server.cmdline.h"
34 #include "user_list.h"
35 #include "server_command_list.h"
36 #include "afs_command_list.h"
40 /** Commands including options must be shorter than this. */
41 #define MAX_COMMAND_LEN 32768
44 extern struct misc_meta_data
*mmd
;
45 extern struct sender senders
[];
46 int send_afs_status(struct rc4_context
*rc4c
, int parser_friendly
);
48 const char *status_item_list
[] = {STATUS_ITEM_ARRAY
};
50 static void dummy(__a_unused
int s
)
54 static void mmd_dup(struct misc_meta_data
*new_mmd
)
56 mutex_lock(mmd_mutex
);
58 mutex_unlock(mmd_mutex
);
62 * Compute human readable string containing vss status for given integer value.
64 * We don't want to use vss_playing() and friends here because we take a
65 * snapshot of the mmd struct and use the copy for computing the state of the
66 * vss. If the real data were used, we would take the mmd lock for a rather
67 * long time or risk to get an inconsistent view.
69 static char *vss_status_tohuman(unsigned int flags
)
71 if (flags
& VSS_PLAYING
)
72 return para_strdup("playing");
74 return para_strdup("stopped");
75 return para_strdup("paused");
79 * return human readable permission string. Never returns NULL.
81 static char *cmd_perms_itohuman(unsigned int perms
)
83 char *msg
= para_malloc(5 * sizeof(char));
85 msg
[0] = perms
& AFS_READ
? 'a' : '-';
86 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
87 msg
[2] = perms
& VSS_READ
? 'v' : '-';
88 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
96 static char *vss_get_status_flags(unsigned int flags
)
98 char *msg
= para_malloc(5 * sizeof(char));
100 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
101 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
102 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
103 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
108 static char *get_status(struct misc_meta_data
*nmmd
, int parser_friendly
)
111 char *status
, *flags
; /* vss status info */
112 char *ut
= uptime_str();
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
);
126 WRITE_STATUS_ITEM(&b
, SI_FILE_SIZE
, "%zu\n", nmmd
->size
/ 1024);
127 WRITE_STATUS_ITEM(&b
, SI_MTIME
, "%s\n", mtime
);
128 WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
129 WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
130 WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
131 WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
132 WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
133 (long unsigned)nmmd
->stream_start
.tv_sec
,
134 (long unsigned)nmmd
->stream_start
.tv_usec
);
135 WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
136 (long unsigned)current_time
.tv_sec
,
137 (long unsigned)current_time
.tv_usec
);
144 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
147 /* this has to match sender.h */
148 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
150 scd
->sender_num
= -1;
152 return -E_COMMAND_SYNTAX
;
153 for (i
= 0; senders
[i
].name
; i
++)
154 if (!strcmp(senders
[i
].name
, argv
[1]))
156 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
157 if (!senders
[i
].name
)
158 return -E_COMMAND_SYNTAX
;
160 for (i
= 0; subcmds
[i
]; i
++)
161 if (!strcmp(subcmds
[i
], argv
[2]))
164 return -E_COMMAND_SYNTAX
;
166 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
167 return -E_SENDER_CMD
;
168 switch (scd
->cmd_num
) {
172 return -E_COMMAND_SYNTAX
;
176 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
177 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
178 return -E_COMMAND_SYNTAX
;
183 return -E_COMMAND_SYNTAX
;
184 return parse_fec_url(argv
[3], scd
);
186 return -E_COMMAND_SYNTAX
;
191 int com_sender(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
194 struct sender_command_data scd
;
198 for (i
= 0; senders
[i
].name
; i
++) {
199 char *tmp
= make_message("%s%s\n",
200 msg
? msg
: "", senders
[i
].name
);
204 ret
= rc4_send_buffer(rc4c
, msg
);
208 ret
= check_sender_args(argc
, argv
, &scd
);
211 if (scd
.sender_num
< 0)
213 msg
= senders
[scd
.sender_num
].help();
214 ret
= rc4_send_buffer(rc4c
, msg
);
218 for (i
= 0; i
< 10; i
++) {
219 mutex_lock(mmd_mutex
);
220 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
221 mutex_unlock(mmd_mutex
);
225 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
226 mutex_unlock(mmd_mutex
);
229 return (i
< 10)? 1 : -E_LOCK
;
233 int com_si(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
237 char *sender_info
= NULL
;
240 return -E_COMMAND_SYNTAX
;
241 mutex_lock(mmd_mutex
);
242 for (i
= 0; senders
[i
].name
; i
++) {
243 char *info
= senders
[i
].info();
244 sender_info
= para_strcat(sender_info
, info
);
248 ret
= rc4_send_va_buffer(rc4c
, "up: %s\nplayed: %u\n"
251 "connections (active/accepted/total): %u/%u/%u\n"
252 "current loglevel: %s\n"
253 "supported audio formats: %s\n"
258 mmd
->active_connections
,
262 supported_audio_formats(),
265 mutex_unlock(mmd_mutex
);
272 int com_version(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
275 return -E_COMMAND_SYNTAX
;
276 return rc4_send_buffer(rc4c
, VERSION_TEXT("server")
277 "built: " BUILD_DATE
"\n"
278 UNAME_RS
", " CC_VERSION
"\n"
282 #define EMPTY_STATUS_ITEMS \
287 ITEM(ATTRIBUTES_BITMAP) \
288 ITEM(ATTRIBUTES_TXT) \
299 ITEM(SECONDS_TOTAL) \
311 * Write a list of audio-file related status items with empty values.
313 * This is used by vss when currently no audio file is open.
315 static char *empty_status_items(int parser_friendly
)
319 #define ITEM(x) "0004 %02x:\n"
322 #define ITEM(x) , SI_ ## x
327 #define ITEM(x) "%s:\n"
330 #define ITEM(x) ,status_item_list[SI_ ## x]
335 #undef EMPTY_STATUS_ITEMS
338 int com_stat(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
341 struct misc_meta_data tmp
, *nmmd
= &tmp
;
344 int parser_friendly
= 0;
346 para_sigaction(SIGUSR1
, dummy
);
348 for (i
= 1; i
< argc
; i
++) {
349 const char *arg
= argv
[i
];
352 if (!strcmp(arg
, "--")) {
356 if (!strncmp(arg
, "-n=", 3)) {
357 ret
= para_atoi32(arg
+ 3, &num
);
362 if (!strcmp(arg
, "-p")) {
366 return -E_COMMAND_SYNTAX
;
369 return -E_COMMAND_SYNTAX
;
372 s
= get_status(nmmd
, parser_friendly
);
373 ret
= rc4_send_buffer(rc4c
, s
);
377 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
380 esi
= empty_status_items(parser_friendly
);
381 ret
= rc4_send_buffer(rc4c
, esi
);
385 send_afs_status(rc4c
, parser_friendly
);
387 if (num
> 0 && !--num
)
391 return -E_SERVER_CRASH
;
397 static int send_list_of_commands(struct rc4_context
*rc4c
, struct server_command
*cmd
,
402 for (i
= 1; cmd
->name
; cmd
++, i
++) {
403 char *perms
= cmd_perms_itohuman(cmd
->perms
);
404 ret
= rc4_send_va_buffer(rc4c
, "%s\t%s\t%s\t%s\n", cmd
->name
,
415 /* returns string that must be freed by the caller */
416 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
418 struct server_command
*cmd
;
420 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
421 if (!strcmp(cmd
->name
, name
)) {
423 *handler
= para_strdup("server"); /* server commands */
426 /* not found, look for commands supported by afs */
427 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
428 if (!strcmp(cmd
->name
, name
)) {
430 *handler
= para_strdup("afs");
437 int com_help(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
439 struct server_command
*cmd
;
440 char *perms
, *handler
;
444 /* no argument given, print list of commands */
445 if ((ret
= send_list_of_commands(rc4c
, server_cmds
, "server")) < 0)
447 return send_list_of_commands(rc4c
, afs_cmds
, "afs");
449 /* argument given for help */
450 cmd
= get_cmd_ptr(argv
[1], &handler
);
455 perms
= cmd_perms_itohuman(cmd
->perms
);
456 ret
= rc4_send_va_buffer(rc4c
,
475 int com_hup(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
478 return -E_COMMAND_SYNTAX
;
479 kill(getppid(), SIGHUP
);
484 int com_term(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
487 return -E_COMMAND_SYNTAX
;
488 kill(getppid(), SIGTERM
);
492 int com_play(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
495 return -E_COMMAND_SYNTAX
;
496 mutex_lock(mmd_mutex
);
497 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
498 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
499 mutex_unlock(mmd_mutex
);
505 int com_stop(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
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_REPOS
;
512 mmd
->new_vss_status_flags
|= VSS_NEXT
;
513 mutex_unlock(mmd_mutex
);
518 int com_pause(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
521 return -E_COMMAND_SYNTAX
;
522 mutex_lock(mmd_mutex
);
523 if (!vss_paused() && !vss_stopped()) {
525 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
526 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
528 mutex_unlock(mmd_mutex
);
533 int com_next(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
536 return -E_COMMAND_SYNTAX
;
537 mutex_lock(mmd_mutex
);
539 mmd
->new_vss_status_flags
|= VSS_NEXT
;
540 mutex_unlock(mmd_mutex
);
545 int com_nomore(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
548 return -E_COMMAND_SYNTAX
;
549 mutex_lock(mmd_mutex
);
550 if (vss_playing() || vss_paused())
551 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
552 mutex_unlock(mmd_mutex
);
557 int com_ff(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
560 int ret
, backwards
= 0;
565 return -E_COMMAND_SYNTAX
;
566 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
567 return -E_COMMAND_SYNTAX
;
568 if (ret
> 1 && c
== '-')
569 backwards
= 1; /* jmp backwards */
570 mutex_lock(mmd_mutex
);
571 ret
= -E_NO_AUDIO_FILE
;
572 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
574 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
576 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
578 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
581 if (promille
> 1000) {
582 mmd
->new_vss_status_flags
|= VSS_NEXT
;
585 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
586 mmd
->new_vss_status_flags
|= VSS_REPOS
;
587 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
591 mutex_unlock(mmd_mutex
);
596 int com_jmp(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
602 return -E_COMMAND_SYNTAX
;
603 if (sscanf(argv
[1], "%lu", &i
) <= 0)
604 return -E_COMMAND_SYNTAX
;
605 mutex_lock(mmd_mutex
);
606 ret
= -E_NO_AUDIO_FILE
;
607 if (!mmd
->afd
.afhi
.chunks_total
)
611 PARA_INFO_LOG("jumping to %lu%%\n", i
);
612 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
613 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
614 mmd
->chunks_sent
, mmd
->offset
);
615 mmd
->new_vss_status_flags
|= VSS_REPOS
;
616 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
620 mutex_unlock(mmd_mutex
);
625 * check if perms are sufficient to exec a command having perms cmd_perms.
626 * Returns 0 if perms are sufficient, -E_PERM otherwise.
628 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
630 PARA_DEBUG_LOG("checking permissions\n");
631 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
635 * Parse first string from *cmd and lookup in table of valid commands.
636 * On error, NULL is returned.
638 static struct server_command
*parse_cmd(const char *cmdstr
)
643 sscanf(cmdstr
, "%200s%n", buf
, &n
);
647 return get_cmd_ptr(buf
, NULL
);
650 static int read_command(struct rc4_context
*rc4c
, char **result
)
654 char *command
= NULL
;
660 ret
= rc4_recv_buffer(rc4c
, buf
, sizeof(buf
));
666 ret
= -E_COMMAND_SYNTAX
;
667 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
669 command
= para_strcat(command
, buf
);
670 p
= strstr(command
, EOC_MSG
);
676 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
686 static void reset_signals(void)
688 para_sigaction(SIGCHLD
, SIG_IGN
);
689 para_sigaction(SIGINT
, SIG_DFL
);
690 para_sigaction(SIGTERM
, SIG_DFL
);
691 para_sigaction(SIGHUP
, SIG_DFL
);
695 * Perform user authentication and execute a command.
697 * \param fd The file descriptor to send output to.
698 * \param peername Identifies the connecting peer.
700 * Whenever para_server accepts an incoming tcp connection on
701 * the port it listens on, it forks and the resulting child
702 * calls this function.
704 * An RSA-based challenge/response is used to authenticate
705 * the peer. It that authentication succeeds, a random RC4
706 * session key is generated and sent back to the peer,
707 * encrypted with its RSA public key. From this point on,
708 * all transfers are crypted with this session key.
710 * Next it is checked if the peer supplied a valid server command or a command
711 * for the audio file selector. If yes, and if the user has sufficient
712 * permissions to execute that command, the function calls the corresponding
713 * command handler which does argument checking and further processing.
715 * In order to cope with a DOS attacks, a timeout is set up
716 * which terminates the function if the connection was not
717 * authenticated when the timeout expires.
719 * \sa alarm(2), rc4(3), crypt.c, crypt.h
721 __noreturn
void handle_connect(int fd
, const char *peername
)
725 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * RC4_KEY_LEN
];
726 unsigned char challenge_sha1
[HASH_SIZE
];
728 struct server_command
*cmd
= NULL
;
730 char *p
, *command
= NULL
;
732 struct rc4_context rc4c
= {.fd
= fd
};
735 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
736 ret
= mark_fd_blocking(fd
);
739 /* send Welcome message */
740 ret
= send_va_buffer(fd
, "This is para_server, version "
741 PACKAGE_VERSION
".\n" );
744 /* recv auth request line */
745 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
749 ret
= -E_AUTH_REQUEST
;
753 ret
= -E_AUTH_REQUEST
;
754 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
756 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
757 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
761 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
762 ret
= para_encrypt_buffer(u
->rsa
, rand_buf
, sizeof(rand_buf
),
763 (unsigned char *)buf
);
769 * We don't want to reveal our user names, so we send a
770 * challenge to the client even if the user does not exist, and
771 * fail the authentication later.
774 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
776 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
777 CHALLENGE_SIZE
, numbytes
);
778 ret
= send_bin_buffer(fd
, buf
, numbytes
);
781 /* recv challenge response */
782 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
786 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret
);
791 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
792 * of the random data.
795 if (numbytes
!= HASH_SIZE
)
797 sha1_hash((char *)rand_buf
, CHALLENGE_SIZE
, challenge_sha1
);
798 if (memcmp(challenge_sha1
, buf
, HASH_SIZE
))
800 /* auth successful */
802 PARA_INFO_LOG("good auth for %s\n", u
->name
);
803 /* init rc4 keys with the second part of the random buffer */
804 RC4_set_key(&rc4c
.recv_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
);
805 RC4_set_key(&rc4c
.send_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
807 ret
= rc4_send_buffer(&rc4c
, PROCEED_MSG
);
810 ret
= read_command(&rc4c
, &command
);
811 if (ret
== -E_COMMAND_SYNTAX
)
816 cmd
= parse_cmd(command
);
819 /* valid command, check permissions */
820 ret
= check_perms(u
->perms
, cmd
);
823 /* valid command and sufficient perms */
824 ret
= create_argv(command
, "\n", &argv
);
828 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
830 ret
= cmd
->handler(&rc4c
, argc
, argv
);
832 mutex_lock(mmd_mutex
);
834 mutex_unlock(mmd_mutex
);
838 rc4_send_va_buffer(&rc4c
, "%s\n", para_strerror(-ret
));
840 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
843 mutex_lock(mmd_mutex
);
844 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
846 mmd
->active_connections
--;
847 mutex_unlock(mmd_mutex
);
848 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);