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"
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
[];
44 int send_afs_status(struct stream_cipher_context
*scc
, int parser_friendly
);
46 const char *status_item_list
[] = {STATUS_ITEM_ARRAY
};
48 static void dummy(__a_unused
int s
)
52 static void mmd_dup(struct misc_meta_data
*new_mmd
)
54 mutex_lock(mmd_mutex
);
56 mutex_unlock(mmd_mutex
);
60 * Compute human readable string containing vss status for given integer value.
62 * We don't want to use vss_playing() and friends here because we take a
63 * snapshot of the mmd struct and use the copy for computing the state of the
64 * vss. If the real data were used, we would take the mmd lock for a rather
65 * long time or risk to get an inconsistent view.
67 static char *vss_status_tohuman(unsigned int flags
)
69 if (flags
& VSS_PLAYING
)
70 return para_strdup("playing");
72 return para_strdup("stopped");
73 return para_strdup("paused");
77 * return human readable permission string. Never returns NULL.
79 static char *cmd_perms_itohuman(unsigned int perms
)
81 char *msg
= para_malloc(5 * sizeof(char));
83 msg
[0] = perms
& AFS_READ
? 'a' : '-';
84 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
85 msg
[2] = perms
& VSS_READ
? 'v' : '-';
86 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
94 static char *vss_get_status_flags(unsigned int flags
)
96 char *msg
= para_malloc(5 * sizeof(char));
98 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
99 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
100 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
101 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
106 static char *get_status(struct misc_meta_data
*nmmd
, int parser_friendly
)
109 char *status
, *flags
; /* vss status info */
110 char *ut
= uptime_str();
111 long offset
= (nmmd
->offset
+ 500) / 1000;
112 struct timeval current_time
;
114 struct para_buffer b
= {.flags
= parser_friendly
? PBF_SIZE_PREFIX
: 0};
116 /* report real status */
117 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
118 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
119 if (nmmd
->size
) { /* parent currently has an audio file open */
120 localtime_r(&nmmd
->mtime
, &mtime_tm
);
121 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
123 gettimeofday(¤t_time
, NULL
);
124 WRITE_STATUS_ITEM(&b
, SI_FILE_SIZE
, "%zu\n", nmmd
->size
/ 1024);
125 WRITE_STATUS_ITEM(&b
, SI_MTIME
, "%s\n", mtime
);
126 WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
127 WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
128 WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
129 WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
130 WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
131 (long unsigned)nmmd
->stream_start
.tv_sec
,
132 (long unsigned)nmmd
->stream_start
.tv_usec
);
133 WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
134 (long unsigned)current_time
.tv_sec
,
135 (long unsigned)current_time
.tv_usec
);
142 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
145 /* this has to match sender.h */
146 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
148 scd
->sender_num
= -1;
150 return -E_COMMAND_SYNTAX
;
151 for (i
= 0; senders
[i
].name
; i
++)
152 if (!strcmp(senders
[i
].name
, argv
[1]))
154 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
155 if (!senders
[i
].name
)
156 return -E_COMMAND_SYNTAX
;
158 for (i
= 0; subcmds
[i
]; i
++)
159 if (!strcmp(subcmds
[i
], argv
[2]))
162 return -E_COMMAND_SYNTAX
;
164 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
165 return -E_SENDER_CMD
;
166 switch (scd
->cmd_num
) {
170 return -E_COMMAND_SYNTAX
;
174 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
175 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
176 return -E_COMMAND_SYNTAX
;
181 return -E_COMMAND_SYNTAX
;
182 return parse_fec_url(argv
[3], scd
);
184 return -E_COMMAND_SYNTAX
;
189 int com_sender(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
193 struct sender_command_data scd
;
196 for (i
= 0; senders
[i
].name
; i
++) {
197 char *tmp
= make_message("%s%s\n",
198 msg
? msg
: "", senders
[i
].name
);
202 ret
= sc_send_buffer(scc
, msg
);
206 ret
= check_sender_args(argc
, argv
, &scd
);
208 if (scd
.sender_num
< 0)
210 msg
= senders
[scd
.sender_num
].help();
211 ret
= sc_send_buffer(scc
, msg
);
216 switch (scd
.cmd_num
) {
219 assert(senders
[scd
.sender_num
].resolve_target
);
220 ret
= senders
[scd
.sender_num
].resolve_target(argv
[3], &scd
);
225 for (i
= 0; i
< 10; i
++) {
226 mutex_lock(mmd_mutex
);
227 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
228 mutex_unlock(mmd_mutex
);
232 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
233 mutex_unlock(mmd_mutex
);
236 return (i
< 10)? 1 : -E_LOCK
;
240 int com_si(struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
244 char *sender_info
= NULL
;
247 return -E_COMMAND_SYNTAX
;
248 mutex_lock(mmd_mutex
);
249 for (i
= 0; senders
[i
].name
; i
++) {
250 char *info
= senders
[i
].info();
251 sender_info
= para_strcat(sender_info
, info
);
255 ret
= sc_send_va_buffer(scc
, "version: " GIT_VERSION
"\n"
256 "up: %s\nplayed: %u\n"
259 "connections (active/accepted/total): %u/%u/%u\n"
260 "current loglevel: %s\n"
261 "supported audio formats: %s\n"
266 mmd
->active_connections
,
270 SERVER_AUDIO_FORMATS
,
273 mutex_unlock(mmd_mutex
);
280 int com_version(struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
283 return -E_COMMAND_SYNTAX
;
284 return sc_send_buffer(scc
, VERSION_TEXT("server")
285 "built: " BUILD_DATE
"\n"
286 UNAME_RS
", " CC_VERSION
"\n"
290 #define EMPTY_STATUS_ITEMS \
295 ITEM(ATTRIBUTES_BITMAP) \
296 ITEM(ATTRIBUTES_TXT) \
307 ITEM(SECONDS_TOTAL) \
319 * Write a list of audio-file related status items with empty values.
321 * This is used by vss when currently no audio file is open.
323 static char *empty_status_items(int parser_friendly
)
327 #define ITEM(x) "0004 %02x:\n"
330 #define ITEM(x) , SI_ ## x
335 #define ITEM(x) "%s:\n"
338 #define ITEM(x) ,status_item_list[SI_ ## x]
343 #undef EMPTY_STATUS_ITEMS
346 int com_stat(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
349 struct misc_meta_data tmp
, *nmmd
= &tmp
;
352 int parser_friendly
= 0;
354 para_sigaction(SIGUSR1
, dummy
);
356 for (i
= 1; i
< argc
; i
++) {
357 const char *arg
= argv
[i
];
360 if (!strcmp(arg
, "--")) {
364 if (!strncmp(arg
, "-n=", 3)) {
365 ret
= para_atoi32(arg
+ 3, &num
);
370 if (!strcmp(arg
, "-p")) {
374 return -E_COMMAND_SYNTAX
;
377 return -E_COMMAND_SYNTAX
;
380 s
= get_status(nmmd
, parser_friendly
);
381 ret
= sc_send_buffer(scc
, s
);
385 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
388 esi
= empty_status_items(parser_friendly
);
389 ret
= sc_send_buffer(scc
, esi
);
393 send_afs_status(scc
, parser_friendly
);
395 if (num
> 0 && !--num
)
399 return -E_SERVER_CRASH
;
405 static int send_list_of_commands(struct stream_cipher_context
*scc
, struct server_command
*cmd
,
410 for (i
= 1; cmd
->name
; cmd
++, i
++) {
411 char *perms
= cmd_perms_itohuman(cmd
->perms
);
412 ret
= sc_send_va_buffer(scc
, "%s\t%s\t%s\t%s\n", cmd
->name
,
423 /* returns string that must be freed by the caller */
424 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
426 struct server_command
*cmd
;
428 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
429 if (!strcmp(cmd
->name
, name
)) {
431 *handler
= para_strdup("server"); /* server commands */
434 /* not found, look for commands supported by afs */
435 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
436 if (!strcmp(cmd
->name
, name
)) {
438 *handler
= para_strdup("afs");
445 int com_help(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
447 struct server_command
*cmd
;
448 char *perms
, *handler
;
452 /* no argument given, print list of commands */
453 if ((ret
= send_list_of_commands(scc
, server_cmds
, "server")) < 0)
455 return send_list_of_commands(scc
, afs_cmds
, "afs");
457 /* argument given for help */
458 cmd
= get_cmd_ptr(argv
[1], &handler
);
461 perms
= cmd_perms_itohuman(cmd
->perms
);
462 ret
= sc_send_va_buffer(scc
,
481 int com_hup(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
484 return -E_COMMAND_SYNTAX
;
485 kill(getppid(), SIGHUP
);
490 int com_term(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
493 return -E_COMMAND_SYNTAX
;
494 kill(getppid(), SIGTERM
);
498 int com_play(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
501 return -E_COMMAND_SYNTAX
;
502 mutex_lock(mmd_mutex
);
503 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
504 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
505 mutex_unlock(mmd_mutex
);
511 int com_stop(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
514 return -E_COMMAND_SYNTAX
;
515 mutex_lock(mmd_mutex
);
516 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
517 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
518 mmd
->new_vss_status_flags
|= VSS_NEXT
;
519 mutex_unlock(mmd_mutex
);
524 int com_pause(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
527 return -E_COMMAND_SYNTAX
;
528 mutex_lock(mmd_mutex
);
529 if (!vss_paused() && !vss_stopped()) {
531 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
532 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
534 mutex_unlock(mmd_mutex
);
539 int com_next(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
542 return -E_COMMAND_SYNTAX
;
543 mutex_lock(mmd_mutex
);
545 mmd
->new_vss_status_flags
|= VSS_NEXT
;
546 mutex_unlock(mmd_mutex
);
551 int com_nomore(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
554 return -E_COMMAND_SYNTAX
;
555 mutex_lock(mmd_mutex
);
556 if (vss_playing() || vss_paused())
557 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
558 mutex_unlock(mmd_mutex
);
563 int com_ff(__a_unused
struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
566 int ret
, backwards
= 0;
571 return -E_COMMAND_SYNTAX
;
572 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
573 return -E_COMMAND_SYNTAX
;
574 if (ret
> 1 && c
== '-')
575 backwards
= 1; /* jmp backwards */
576 mutex_lock(mmd_mutex
);
577 ret
= -E_NO_AUDIO_FILE
;
578 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
580 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
582 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
584 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
587 if (promille
> 1000) {
588 mmd
->new_vss_status_flags
|= VSS_NEXT
;
591 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
592 mmd
->new_vss_status_flags
|= VSS_REPOS
;
593 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
597 mutex_unlock(mmd_mutex
);
602 int com_jmp(__a_unused
struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
608 return -E_COMMAND_SYNTAX
;
609 if (sscanf(argv
[1], "%lu", &i
) <= 0)
610 return -E_COMMAND_SYNTAX
;
611 mutex_lock(mmd_mutex
);
612 ret
= -E_NO_AUDIO_FILE
;
613 if (!mmd
->afd
.afhi
.chunks_total
)
617 PARA_INFO_LOG("jumping to %lu%%\n", i
);
618 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
619 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
620 mmd
->chunks_sent
, mmd
->offset
);
621 mmd
->new_vss_status_flags
|= VSS_REPOS
;
622 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
626 mutex_unlock(mmd_mutex
);
631 * check if perms are sufficient to exec a command having perms cmd_perms.
632 * Returns 0 if perms are sufficient, -E_PERM otherwise.
634 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
636 PARA_DEBUG_LOG("checking permissions\n");
637 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
641 * Parse first string from *cmd and lookup in table of valid commands.
642 * On error, NULL is returned.
644 static struct server_command
*parse_cmd(const char *cmdstr
)
649 sscanf(cmdstr
, "%200s%n", buf
, &n
);
653 return get_cmd_ptr(buf
, NULL
);
656 static int read_command(struct stream_cipher_context
*scc
, char **result
)
660 char *command
= NULL
;
666 ret
= sc_recv_buffer(scc
, buf
, sizeof(buf
));
672 ret
= -E_COMMAND_SYNTAX
;
673 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
675 command
= para_strcat(command
, buf
);
676 p
= strstr(command
, EOC_MSG
);
682 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
692 static void reset_signals(void)
694 para_sigaction(SIGCHLD
, SIG_IGN
);
695 para_sigaction(SIGINT
, SIG_DFL
);
696 para_sigaction(SIGTERM
, SIG_DFL
);
697 para_sigaction(SIGHUP
, SIG_DFL
);
701 * Perform user authentication and execute a command.
703 * \param fd The file descriptor to send output to.
704 * \param peername Identifies the connecting peer.
706 * Whenever para_server accepts an incoming tcp connection on
707 * the port it listens on, it forks and the resulting child
708 * calls this function.
710 * An RSA-based challenge/response is used to authenticate
711 * the peer. It that authentication succeeds, a random
712 * session key is generated and sent back to the peer,
713 * encrypted with its RSA public key. From this point on,
714 * all transfers are crypted with this session key.
716 * Next it is checked if the peer supplied a valid server command or a command
717 * for the audio file selector. If yes, and if the user has sufficient
718 * permissions to execute that command, the function calls the corresponding
719 * command handler which does argument checking and further processing.
721 * In order to cope with a DOS attacks, a timeout is set up
722 * which terminates the function if the connection was not
723 * authenticated when the timeout expires.
725 * \sa alarm(2), crypt.c, crypt.h
727 __noreturn
void handle_connect(int fd
, const char *peername
)
731 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * SESSION_KEY_LEN
];
732 unsigned char challenge_hash
[HASH_SIZE
];
734 struct server_command
*cmd
= NULL
;
736 char *p
, *command
= NULL
;
738 struct stream_cipher_context scc
= {.fd
= fd
};
741 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
742 ret
= mark_fd_blocking(fd
);
745 /* send Welcome message */
746 ret
= send_va_buffer(fd
, "This is para_server, version "
747 PACKAGE_VERSION
".\n" );
750 /* recv auth request line */
751 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
755 ret
= -E_AUTH_REQUEST
;
759 ret
= -E_AUTH_REQUEST
;
760 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
762 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
763 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
767 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
768 ret
= pub_encrypt(u
->pubkey
, rand_buf
, sizeof(rand_buf
),
769 (unsigned char *)buf
);
775 * We don't want to reveal our user names, so we send a
776 * challenge to the client even if the user does not exist, and
777 * fail the authentication later.
780 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
782 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
783 CHALLENGE_SIZE
, numbytes
);
784 ret
= send_bin_buffer(fd
, buf
, numbytes
);
787 /* recv challenge response */
788 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
792 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret
);
797 * The correct response is the hash of the first CHALLENGE_SIZE bytes
798 * of the random data.
801 if (numbytes
!= HASH_SIZE
)
803 hash_function((char *)rand_buf
, CHALLENGE_SIZE
, challenge_hash
);
804 if (memcmp(challenge_hash
, buf
, HASH_SIZE
))
806 /* auth successful */
808 PARA_INFO_LOG("good auth for %s\n", u
->name
);
809 /* init stream cipher keys with the second part of the random buffer */
810 scc
.recv
= sc_new(rand_buf
+ CHALLENGE_SIZE
, SESSION_KEY_LEN
);
811 scc
.send
= sc_new(rand_buf
+ CHALLENGE_SIZE
+ SESSION_KEY_LEN
, SESSION_KEY_LEN
);
812 ret
= sc_send_buffer(&scc
, PROCEED_MSG
);
815 ret
= read_command(&scc
, &command
);
816 if (ret
== -E_COMMAND_SYNTAX
)
821 cmd
= parse_cmd(command
);
824 /* valid command, check permissions */
825 ret
= check_perms(u
->perms
, cmd
);
828 /* valid command and sufficient perms */
829 ret
= create_argv(command
, "\n", &argv
);
833 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
835 ret
= cmd
->handler(&scc
, argc
, argv
);
837 mutex_lock(mmd_mutex
);
839 mutex_unlock(mmd_mutex
);
843 sc_send_va_buffer(&scc
, "%s\n", para_strerror(-ret
));
845 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
850 mutex_lock(mmd_mutex
);
851 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
853 mmd
->active_connections
--;
854 mutex_unlock(mmd_mutex
);
855 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);