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>
14 #include <openssl/rc4.h>
22 #include "server.cmdline.h"
35 #include "user_list.h"
36 #include "server_command_list.h"
37 #include "afs_command_list.h"
41 /** Commands including options must be shorter than this. */
42 #define MAX_COMMAND_LEN 32768
45 extern struct misc_meta_data
*mmd
;
46 extern struct sender senders
[];
47 int send_afs_status(struct rc4_context
*rc4c
, int parser_friendly
);
49 const char *status_item_list
[] = {STATUS_ITEM_ARRAY
};
51 static void dummy(__a_unused
int s
)
55 static void mmd_dup(struct misc_meta_data
*new_mmd
)
57 mutex_lock(mmd_mutex
);
59 mutex_unlock(mmd_mutex
);
63 * Compute human readable string containing vss status for given integer value.
65 * We don't want to use vss_playing() and friends here because we take a
66 * snapshot of the mmd struct and use the copy for computing the state of the
67 * vss. If the real data were used, we would take the mmd lock for a rather
68 * long time or risk to get an inconsistent view.
70 static char *vss_status_tohuman(unsigned int flags
)
72 if (flags
& VSS_PLAYING
)
73 return para_strdup("playing");
75 return para_strdup("stopped");
76 return para_strdup("paused");
80 * return human readable permission string. Never returns NULL.
82 static char *cmd_perms_itohuman(unsigned int perms
)
84 char *msg
= para_malloc(5 * sizeof(char));
86 msg
[0] = perms
& AFS_READ
? 'a' : '-';
87 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
88 msg
[2] = perms
& VSS_READ
? 'v' : '-';
89 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
97 static char *vss_get_status_flags(unsigned int flags
)
99 char *msg
= para_malloc(5 * sizeof(char));
101 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
102 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
103 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
104 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
109 static char *get_status(struct misc_meta_data
*nmmd
, int parser_friendly
)
112 char *status
, *flags
; /* vss status info */
113 char *ut
= uptime_str();
114 long offset
= (nmmd
->offset
+ 500) / 1000;
115 struct timeval current_time
;
117 struct para_buffer b
= {.flags
= parser_friendly
? PBF_SIZE_PREFIX
: 0};
119 /* report real status */
120 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
121 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
122 if (nmmd
->size
) { /* parent currently has an audio file open */
123 localtime_r(&nmmd
->mtime
, &mtime_tm
);
124 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
126 gettimeofday(¤t_time
, NULL
);
127 WRITE_STATUS_ITEM(&b
, SI_FILE_SIZE
, "%zu\n", nmmd
->size
/ 1024);
128 WRITE_STATUS_ITEM(&b
, SI_MTIME
, "%s\n", mtime
);
129 WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
130 WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
131 WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
132 WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
133 WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
134 (long unsigned)nmmd
->stream_start
.tv_sec
,
135 (long unsigned)nmmd
->stream_start
.tv_usec
);
136 WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
137 (long unsigned)current_time
.tv_sec
,
138 (long unsigned)current_time
.tv_usec
);
145 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
148 /* this has to match sender.h */
149 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
151 scd
->sender_num
= -1;
153 return -E_COMMAND_SYNTAX
;
154 for (i
= 0; senders
[i
].name
; i
++)
155 if (!strcmp(senders
[i
].name
, argv
[1]))
157 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
158 if (!senders
[i
].name
)
159 return -E_COMMAND_SYNTAX
;
161 for (i
= 0; subcmds
[i
]; i
++)
162 if (!strcmp(subcmds
[i
], argv
[2]))
165 return -E_COMMAND_SYNTAX
;
167 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
168 return -E_SENDER_CMD
;
169 switch (scd
->cmd_num
) {
173 return -E_COMMAND_SYNTAX
;
177 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
178 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
179 return -E_COMMAND_SYNTAX
;
184 return -E_COMMAND_SYNTAX
;
185 return parse_fec_url(argv
[3], scd
);
187 return -E_COMMAND_SYNTAX
;
192 int com_sender(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
196 struct sender_command_data scd
;
199 for (i
= 0; senders
[i
].name
; i
++) {
200 char *tmp
= make_message("%s%s\n",
201 msg
? msg
: "", senders
[i
].name
);
205 ret
= rc4_send_buffer(rc4c
, msg
);
209 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
);
219 switch (scd
.cmd_num
) {
222 assert(senders
[scd
.sender_num
].resolve_target
);
223 ret
= senders
[scd
.sender_num
].resolve_target(argv
[3], &scd
);
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
;
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
);
258 ret
= rc4_send_va_buffer(rc4c
, "version: " GIT_VERSION
"\n"
259 "up: %s\nplayed: %u\n"
262 "connections (active/accepted/total): %u/%u/%u\n"
263 "current loglevel: %s\n"
264 "supported audio formats: %s\n"
269 mmd
->active_connections
,
273 SERVER_AUDIO_FORMATS
,
276 mutex_unlock(mmd_mutex
);
283 int com_version(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
286 return -E_COMMAND_SYNTAX
;
287 return rc4_send_buffer(rc4c
, VERSION_TEXT("server")
288 "built: " BUILD_DATE
"\n"
289 UNAME_RS
", " CC_VERSION
"\n"
293 #define EMPTY_STATUS_ITEMS \
298 ITEM(ATTRIBUTES_BITMAP) \
299 ITEM(ATTRIBUTES_TXT) \
310 ITEM(SECONDS_TOTAL) \
322 * Write a list of audio-file related status items with empty values.
324 * This is used by vss when currently no audio file is open.
326 static char *empty_status_items(int parser_friendly
)
330 #define ITEM(x) "0004 %02x:\n"
333 #define ITEM(x) , SI_ ## x
338 #define ITEM(x) "%s:\n"
341 #define ITEM(x) ,status_item_list[SI_ ## x]
346 #undef EMPTY_STATUS_ITEMS
349 int com_stat(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
352 struct misc_meta_data tmp
, *nmmd
= &tmp
;
355 int parser_friendly
= 0;
357 para_sigaction(SIGUSR1
, dummy
);
359 for (i
= 1; i
< argc
; i
++) {
360 const char *arg
= argv
[i
];
363 if (!strcmp(arg
, "--")) {
367 if (!strncmp(arg
, "-n=", 3)) {
368 ret
= para_atoi32(arg
+ 3, &num
);
373 if (!strcmp(arg
, "-p")) {
377 return -E_COMMAND_SYNTAX
;
380 return -E_COMMAND_SYNTAX
;
383 s
= get_status(nmmd
, parser_friendly
);
384 ret
= rc4_send_buffer(rc4c
, s
);
388 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
391 esi
= empty_status_items(parser_friendly
);
392 ret
= rc4_send_buffer(rc4c
, esi
);
396 send_afs_status(rc4c
, parser_friendly
);
398 if (num
> 0 && !--num
)
402 return -E_SERVER_CRASH
;
408 static int send_list_of_commands(struct rc4_context
*rc4c
, struct server_command
*cmd
,
413 for (i
= 1; cmd
->name
; cmd
++, i
++) {
414 char *perms
= cmd_perms_itohuman(cmd
->perms
);
415 ret
= rc4_send_va_buffer(rc4c
, "%s\t%s\t%s\t%s\n", cmd
->name
,
426 /* returns string that must be freed by the caller */
427 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
429 struct server_command
*cmd
;
431 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
432 if (!strcmp(cmd
->name
, name
)) {
434 *handler
= para_strdup("server"); /* server commands */
437 /* not found, look for commands supported by afs */
438 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
439 if (!strcmp(cmd
->name
, name
)) {
441 *handler
= para_strdup("afs");
448 int com_help(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
450 struct server_command
*cmd
;
451 char *perms
, *handler
;
455 /* no argument given, print list of commands */
456 if ((ret
= send_list_of_commands(rc4c
, server_cmds
, "server")) < 0)
458 return send_list_of_commands(rc4c
, afs_cmds
, "afs");
460 /* argument given for help */
461 cmd
= get_cmd_ptr(argv
[1], &handler
);
464 perms
= cmd_perms_itohuman(cmd
->perms
);
465 ret
= rc4_send_va_buffer(rc4c
,
484 int com_hup(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
487 return -E_COMMAND_SYNTAX
;
488 kill(getppid(), SIGHUP
);
493 int com_term(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
496 return -E_COMMAND_SYNTAX
;
497 kill(getppid(), SIGTERM
);
501 int com_play(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
504 return -E_COMMAND_SYNTAX
;
505 mutex_lock(mmd_mutex
);
506 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
507 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
508 mutex_unlock(mmd_mutex
);
514 int com_stop(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
517 return -E_COMMAND_SYNTAX
;
518 mutex_lock(mmd_mutex
);
519 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
520 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
521 mmd
->new_vss_status_flags
|= VSS_NEXT
;
522 mutex_unlock(mmd_mutex
);
527 int com_pause(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
530 return -E_COMMAND_SYNTAX
;
531 mutex_lock(mmd_mutex
);
532 if (!vss_paused() && !vss_stopped()) {
534 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
535 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
537 mutex_unlock(mmd_mutex
);
542 int com_next(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
545 return -E_COMMAND_SYNTAX
;
546 mutex_lock(mmd_mutex
);
548 mmd
->new_vss_status_flags
|= VSS_NEXT
;
549 mutex_unlock(mmd_mutex
);
554 int com_nomore(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
557 return -E_COMMAND_SYNTAX
;
558 mutex_lock(mmd_mutex
);
559 if (vss_playing() || vss_paused())
560 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
561 mutex_unlock(mmd_mutex
);
566 int com_ff(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
569 int ret
, backwards
= 0;
574 return -E_COMMAND_SYNTAX
;
575 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
576 return -E_COMMAND_SYNTAX
;
577 if (ret
> 1 && c
== '-')
578 backwards
= 1; /* jmp backwards */
579 mutex_lock(mmd_mutex
);
580 ret
= -E_NO_AUDIO_FILE
;
581 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
583 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
585 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
587 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
590 if (promille
> 1000) {
591 mmd
->new_vss_status_flags
|= VSS_NEXT
;
594 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
595 mmd
->new_vss_status_flags
|= VSS_REPOS
;
596 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
600 mutex_unlock(mmd_mutex
);
605 int com_jmp(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
611 return -E_COMMAND_SYNTAX
;
612 if (sscanf(argv
[1], "%lu", &i
) <= 0)
613 return -E_COMMAND_SYNTAX
;
614 mutex_lock(mmd_mutex
);
615 ret
= -E_NO_AUDIO_FILE
;
616 if (!mmd
->afd
.afhi
.chunks_total
)
620 PARA_INFO_LOG("jumping to %lu%%\n", i
);
621 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
622 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
623 mmd
->chunks_sent
, mmd
->offset
);
624 mmd
->new_vss_status_flags
|= VSS_REPOS
;
625 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
629 mutex_unlock(mmd_mutex
);
634 * check if perms are sufficient to exec a command having perms cmd_perms.
635 * Returns 0 if perms are sufficient, -E_PERM otherwise.
637 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
639 PARA_DEBUG_LOG("checking permissions\n");
640 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
644 * Parse first string from *cmd and lookup in table of valid commands.
645 * On error, NULL is returned.
647 static struct server_command
*parse_cmd(const char *cmdstr
)
652 sscanf(cmdstr
, "%200s%n", buf
, &n
);
656 return get_cmd_ptr(buf
, NULL
);
659 static int read_command(struct rc4_context
*rc4c
, char **result
)
663 char *command
= NULL
;
669 ret
= rc4_recv_buffer(rc4c
, buf
, sizeof(buf
));
675 ret
= -E_COMMAND_SYNTAX
;
676 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
678 command
= para_strcat(command
, buf
);
679 p
= strstr(command
, EOC_MSG
);
685 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
695 static void reset_signals(void)
697 para_sigaction(SIGCHLD
, SIG_IGN
);
698 para_sigaction(SIGINT
, SIG_DFL
);
699 para_sigaction(SIGTERM
, SIG_DFL
);
700 para_sigaction(SIGHUP
, SIG_DFL
);
704 * Perform user authentication and execute a command.
706 * \param fd The file descriptor to send output to.
707 * \param peername Identifies the connecting peer.
709 * Whenever para_server accepts an incoming tcp connection on
710 * the port it listens on, it forks and the resulting child
711 * calls this function.
713 * An RSA-based challenge/response is used to authenticate
714 * the peer. It that authentication succeeds, a random RC4
715 * session key is generated and sent back to the peer,
716 * encrypted with its RSA public key. From this point on,
717 * all transfers are crypted with this session key.
719 * Next it is checked if the peer supplied a valid server command or a command
720 * for the audio file selector. If yes, and if the user has sufficient
721 * permissions to execute that command, the function calls the corresponding
722 * command handler which does argument checking and further processing.
724 * In order to cope with a DOS attacks, a timeout is set up
725 * which terminates the function if the connection was not
726 * authenticated when the timeout expires.
728 * \sa alarm(2), rc4(3), crypt.c, crypt.h
730 __noreturn
void handle_connect(int fd
, const char *peername
)
734 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * RC4_KEY_LEN
];
735 unsigned char challenge_sha1
[HASH_SIZE
];
737 struct server_command
*cmd
= NULL
;
739 char *p
, *command
= NULL
;
741 struct rc4_context rc4c
= {.fd
= fd
};
744 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
745 ret
= mark_fd_blocking(fd
);
748 /* send Welcome message */
749 ret
= send_va_buffer(fd
, "This is para_server, version "
750 PACKAGE_VERSION
".\n" );
753 /* recv auth request line */
754 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
758 ret
= -E_AUTH_REQUEST
;
762 ret
= -E_AUTH_REQUEST
;
763 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
765 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
766 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
770 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
771 ret
= para_encrypt_buffer(u
->rsa
, rand_buf
, sizeof(rand_buf
),
772 (unsigned char *)buf
);
778 * We don't want to reveal our user names, so we send a
779 * challenge to the client even if the user does not exist, and
780 * fail the authentication later.
783 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
785 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
786 CHALLENGE_SIZE
, numbytes
);
787 ret
= send_bin_buffer(fd
, buf
, numbytes
);
790 /* recv challenge response */
791 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
795 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret
);
800 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
801 * of the random data.
804 if (numbytes
!= HASH_SIZE
)
806 sha1_hash((char *)rand_buf
, CHALLENGE_SIZE
, challenge_sha1
);
807 if (memcmp(challenge_sha1
, buf
, HASH_SIZE
))
809 /* auth successful */
811 PARA_INFO_LOG("good auth for %s\n", u
->name
);
812 /* init rc4 keys with the second part of the random buffer */
813 RC4_set_key(&rc4c
.recv_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
);
814 RC4_set_key(&rc4c
.send_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
816 ret
= rc4_send_buffer(&rc4c
, PROCEED_MSG
);
819 ret
= read_command(&rc4c
, &command
);
820 if (ret
== -E_COMMAND_SYNTAX
)
825 cmd
= parse_cmd(command
);
828 /* valid command, check permissions */
829 ret
= check_perms(u
->perms
, cmd
);
832 /* valid command and sufficient perms */
833 ret
= create_argv(command
, "\n", &argv
);
837 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
839 ret
= cmd
->handler(&rc4c
, argc
, argv
);
841 mutex_lock(mmd_mutex
);
843 mutex_unlock(mmd_mutex
);
847 rc4_send_va_buffer(&rc4c
, "%s\n", para_strerror(-ret
));
849 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
852 mutex_lock(mmd_mutex
);
853 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
855 mmd
->active_connections
--;
856 mutex_unlock(mmd_mutex
);
857 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);