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>
20 #include "server.cmdline.h"
33 #include "user_list.h"
34 #include "server_command_list.h"
35 #include "afs_command_list.h"
39 /** Commands including options must be shorter than this. */
40 #define MAX_COMMAND_LEN 32768
43 extern struct misc_meta_data
*mmd
;
44 extern struct sender senders
[];
45 int send_afs_status(struct rc4_context
*rc4c
, int parser_friendly
);
47 const char *status_item_list
[] = {STATUS_ITEM_ARRAY
};
49 static void dummy(__a_unused
int s
)
53 static void mmd_dup(struct misc_meta_data
*new_mmd
)
55 mutex_lock(mmd_mutex
);
57 mutex_unlock(mmd_mutex
);
61 * Compute human readable string containing vss status for given integer value.
63 * We don't want to use vss_playing() and friends here because we take a
64 * snapshot of the mmd struct and use the copy for computing the state of the
65 * vss. If the real data were used, we would take the mmd lock for a rather
66 * long time or risk to get an inconsistent view.
68 static char *vss_status_tohuman(unsigned int flags
)
70 if (flags
& VSS_PLAYING
)
71 return para_strdup("playing");
73 return para_strdup("stopped");
74 return para_strdup("paused");
78 * return human readable permission string. Never returns NULL.
80 static char *cmd_perms_itohuman(unsigned int perms
)
82 char *msg
= para_malloc(5 * sizeof(char));
84 msg
[0] = perms
& AFS_READ
? 'a' : '-';
85 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
86 msg
[2] = perms
& VSS_READ
? 'v' : '-';
87 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
95 static char *vss_get_status_flags(unsigned int flags
)
97 char *msg
= para_malloc(5 * sizeof(char));
99 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
100 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
101 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
102 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
107 static char *get_status(struct misc_meta_data
*nmmd
, int parser_friendly
)
110 char *status
, *flags
; /* vss status info */
111 char *ut
= uptime_str();
112 long offset
= (nmmd
->offset
+ 500) / 1000;
113 struct timeval current_time
;
115 struct para_buffer b
= {.flags
= parser_friendly
? PBF_SIZE_PREFIX
: 0};
117 /* report real status */
118 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
119 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
120 if (nmmd
->size
) { /* parent currently has an audio file open */
121 localtime_r(&nmmd
->mtime
, &mtime_tm
);
122 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
124 gettimeofday(¤t_time
, NULL
);
125 WRITE_STATUS_ITEM(&b
, SI_FILE_SIZE
, "%zu\n", nmmd
->size
/ 1024);
126 WRITE_STATUS_ITEM(&b
, SI_MTIME
, "%s\n", mtime
);
127 WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
128 WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
129 WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
130 WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
131 WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
132 (long unsigned)nmmd
->stream_start
.tv_sec
,
133 (long unsigned)nmmd
->stream_start
.tv_usec
);
134 WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
135 (long unsigned)current_time
.tv_sec
,
136 (long unsigned)current_time
.tv_usec
);
143 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
146 /* this has to match sender.h */
147 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
149 scd
->sender_num
= -1;
151 return -E_COMMAND_SYNTAX
;
152 for (i
= 0; senders
[i
].name
; i
++)
153 if (!strcmp(senders
[i
].name
, argv
[1]))
155 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
156 if (!senders
[i
].name
)
157 return -E_COMMAND_SYNTAX
;
159 for (i
= 0; subcmds
[i
]; i
++)
160 if (!strcmp(subcmds
[i
], argv
[2]))
163 return -E_COMMAND_SYNTAX
;
165 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
166 return -E_SENDER_CMD
;
167 switch (scd
->cmd_num
) {
171 return -E_COMMAND_SYNTAX
;
175 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
176 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
177 return -E_COMMAND_SYNTAX
;
182 return -E_COMMAND_SYNTAX
;
183 return parse_fec_url(argv
[3], scd
);
185 return -E_COMMAND_SYNTAX
;
190 int com_sender(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
193 struct sender_command_data scd
;
197 for (i
= 0; senders
[i
].name
; i
++) {
198 char *tmp
= make_message("%s%s\n",
199 msg
? msg
: "", senders
[i
].name
);
203 ret
= rc4_send_buffer(rc4c
, msg
);
207 ret
= check_sender_args(argc
, argv
, &scd
);
210 if (scd
.sender_num
< 0)
212 msg
= senders
[scd
.sender_num
].help();
213 ret
= rc4_send_buffer(rc4c
, msg
);
217 for (i
= 0; i
< 10; i
++) {
218 mutex_lock(mmd_mutex
);
219 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
220 mutex_unlock(mmd_mutex
);
224 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
225 mutex_unlock(mmd_mutex
);
228 return (i
< 10)? 1 : -E_LOCK
;
232 int com_si(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
236 char *sender_info
= NULL
, *sender_list
= NULL
;
239 return -E_COMMAND_SYNTAX
;
240 mutex_lock(mmd_mutex
);
241 for (i
= 0; senders
[i
].name
; i
++) {
242 char *info
= senders
[i
].info();
243 sender_info
= para_strcat(sender_info
, info
);
245 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
246 sender_list
= para_strcat(sender_list
, " ");
249 ret
= rc4_send_va_buffer(rc4c
, "up: %s\nplayed: %u\n"
252 "connections (active/accepted/total): %u/%u/%u\n"
253 "current loglevel: %s\n"
254 "supported audio formats: %s\n"
255 "supported senders: %s\n"
260 mmd
->active_connections
,
264 supported_audio_formats(),
268 mutex_unlock(mmd_mutex
);
276 int com_version(struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
279 return -E_COMMAND_SYNTAX
;
280 return rc4_send_buffer(rc4c
, VERSION_TEXT("server")
281 "built: " BUILD_DATE
"\n"
282 UNAME_RS
", " CC_VERSION
"\n"
286 #define EMPTY_STATUS_ITEMS \
291 ITEM(ATTRIBUTES_BITMAP) \
292 ITEM(ATTRIBUTES_TXT) \
303 ITEM(SECONDS_TOTAL) \
315 * Write a list of audio-file related status items with empty values.
317 * This is used by vss when currently no audio file is open.
319 static char *empty_status_items(int parser_friendly
)
323 #define ITEM(x) "0004 %02x:\n"
326 #define ITEM(x) , SI_ ## x
331 #define ITEM(x) "%s:\n"
334 #define ITEM(x) ,status_item_list[SI_ ## x]
339 #undef EMPTY_STATUS_ITEMS
342 int com_stat(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
345 struct misc_meta_data tmp
, *nmmd
= &tmp
;
348 int parser_friendly
= 0;
350 para_sigaction(SIGUSR1
, dummy
);
352 for (i
= 1; i
< argc
; i
++) {
353 const char *arg
= argv
[i
];
356 if (!strcmp(arg
, "--")) {
360 if (!strncmp(arg
, "-n=", 3)) {
361 ret
= para_atoi32(arg
+ 3, &num
);
366 if (!strcmp(arg
, "-p")) {
372 return -E_COMMAND_SYNTAX
;
375 s
= get_status(nmmd
, parser_friendly
);
376 ret
= rc4_send_buffer(rc4c
, s
);
380 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
383 esi
= empty_status_items(parser_friendly
);
384 ret
= rc4_send_buffer(rc4c
, esi
);
388 send_afs_status(rc4c
, parser_friendly
);
390 if (num
> 0 && !--num
)
394 return -E_SERVER_CRASH
;
400 static int send_list_of_commands(struct rc4_context
*rc4c
, struct server_command
*cmd
,
405 for (i
= 1; cmd
->name
; cmd
++, i
++) {
406 char *perms
= cmd_perms_itohuman(cmd
->perms
);
407 ret
= rc4_send_va_buffer(rc4c
, "%s\t%s\t%s\t%s\n", cmd
->name
,
418 /* returns string that must be freed by the caller */
419 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
421 struct server_command
*cmd
;
423 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
424 if (!strcmp(cmd
->name
, name
)) {
426 *handler
= para_strdup("server"); /* server commands */
429 /* not found, look for commands supported by afs */
430 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
431 if (!strcmp(cmd
->name
, name
)) {
433 *handler
= para_strdup("afs");
440 int com_help(struct rc4_context
*rc4c
, int argc
, char * const * argv
)
442 struct server_command
*cmd
;
443 char *perms
, *handler
;
447 /* no argument given, print list of commands */
448 if ((ret
= send_list_of_commands(rc4c
, server_cmds
, "server")) < 0)
450 return send_list_of_commands(rc4c
, afs_cmds
, "afs");
452 /* argument given for help */
453 cmd
= get_cmd_ptr(argv
[1], &handler
);
458 perms
= cmd_perms_itohuman(cmd
->perms
);
459 ret
= rc4_send_va_buffer(rc4c
,
478 int com_hup(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
481 return -E_COMMAND_SYNTAX
;
482 kill(getppid(), SIGHUP
);
487 int com_term(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
490 return -E_COMMAND_SYNTAX
;
491 kill(getppid(), SIGTERM
);
495 int com_play(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
498 return -E_COMMAND_SYNTAX
;
499 mutex_lock(mmd_mutex
);
500 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
501 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
502 mutex_unlock(mmd_mutex
);
508 int com_stop(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
511 return -E_COMMAND_SYNTAX
;
512 mutex_lock(mmd_mutex
);
513 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
514 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
515 mmd
->new_vss_status_flags
|= VSS_NEXT
;
516 mutex_unlock(mmd_mutex
);
521 int com_pause(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
524 return -E_COMMAND_SYNTAX
;
525 mutex_lock(mmd_mutex
);
526 if (!vss_paused() && !vss_stopped()) {
528 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
529 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
531 mutex_unlock(mmd_mutex
);
536 int com_next(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
539 return -E_COMMAND_SYNTAX
;
540 mutex_lock(mmd_mutex
);
542 mmd
->new_vss_status_flags
|= VSS_NEXT
;
543 mutex_unlock(mmd_mutex
);
548 int com_nomore(__a_unused
struct rc4_context
*rc4c
, int argc
, __a_unused
char * const * argv
)
551 return -E_COMMAND_SYNTAX
;
552 mutex_lock(mmd_mutex
);
553 if (vss_playing() || vss_paused())
554 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
555 mutex_unlock(mmd_mutex
);
560 int com_ff(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
563 int ret
, backwards
= 0;
568 return -E_COMMAND_SYNTAX
;
569 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
570 return -E_COMMAND_SYNTAX
;
571 if (ret
> 1 && c
== '-')
572 backwards
= 1; /* jmp backwards */
573 mutex_lock(mmd_mutex
);
574 ret
= -E_NO_AUDIO_FILE
;
575 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
577 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
579 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
581 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
584 if (promille
> 1000) {
585 mmd
->new_vss_status_flags
|= VSS_NEXT
;
588 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
589 mmd
->new_vss_status_flags
|= VSS_REPOS
;
590 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
594 mutex_unlock(mmd_mutex
);
599 int com_jmp(__a_unused
struct rc4_context
*rc4c
, int argc
, char * const * argv
)
605 return -E_COMMAND_SYNTAX
;
606 if (sscanf(argv
[1], "%lu", &i
) <= 0)
607 return -E_COMMAND_SYNTAX
;
608 mutex_lock(mmd_mutex
);
609 ret
= -E_NO_AUDIO_FILE
;
610 if (!mmd
->afd
.afhi
.chunks_total
)
614 PARA_INFO_LOG("jumping to %lu%%\n", i
);
615 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
616 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
617 mmd
->chunks_sent
, mmd
->offset
);
618 mmd
->new_vss_status_flags
|= VSS_REPOS
;
619 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
623 mutex_unlock(mmd_mutex
);
628 * check if perms are sufficient to exec a command having perms cmd_perms.
629 * Returns 0 if perms are sufficient, -E_PERM otherwise.
631 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
633 PARA_DEBUG_LOG("checking permissions\n");
634 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
638 * Parse first string from *cmd and lookup in table of valid commands.
639 * On error, NULL is returned.
641 static struct server_command
*parse_cmd(const char *cmdstr
)
646 sscanf(cmdstr
, "%200s%n", buf
, &n
);
650 return get_cmd_ptr(buf
, NULL
);
653 static int read_command(struct rc4_context
*rc4c
, char **result
)
657 char *command
= NULL
;
663 ret
= rc4_recv_buffer(rc4c
, buf
, sizeof(buf
));
669 ret
= -E_COMMAND_SYNTAX
;
670 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
672 command
= para_strcat(command
, buf
);
673 p
= strstr(command
, EOC_MSG
);
679 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
689 static void reset_signals(void)
691 para_sigaction(SIGCHLD
, SIG_IGN
);
692 para_sigaction(SIGINT
, SIG_DFL
);
693 para_sigaction(SIGTERM
, SIG_DFL
);
694 para_sigaction(SIGHUP
, SIG_DFL
);
698 * Perform user authentication and execute a command.
700 * \param fd The file descriptor to send output to.
701 * \param peername Identifies the connecting peer.
703 * Whenever para_server accepts an incoming tcp connection on
704 * the port it listens on, it forks and the resulting child
705 * calls this function.
707 * An RSA-based challenge/response is used to authenticate
708 * the peer. It that authentication succeeds, a random RC4
709 * session key is generated and sent back to the peer,
710 * encrypted with its RSA public key. From this point on,
711 * all transfers are crypted with this session key.
713 * Next it is checked if the peer supplied a valid server command or a command
714 * for the audio file selector. If yes, and if the user has sufficient
715 * permissions to execute that command, the function calls the corresponding
716 * command handler which does argument checking and further processing.
718 * In order to cope with a DOS attacks, a timeout is set up
719 * which terminates the function if the connection was not
720 * authenticated when the timeout expires.
722 * \sa alarm(2), rc4(3), crypt.c, crypt.h
724 __noreturn
void handle_connect(int fd
, const char *peername
)
728 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * RC4_KEY_LEN
];
729 unsigned char challenge_sha1
[HASH_SIZE
];
731 struct server_command
*cmd
= NULL
;
733 char *p
, *command
= NULL
;
735 struct rc4_context rc4c
= {.fd
= fd
};
738 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
739 ret
= mark_fd_blocking(fd
);
742 /* send Welcome message */
743 ret
= send_va_buffer(fd
, "This is para_server, version "
744 PACKAGE_VERSION
".\n" );
747 /* recv auth request line */
748 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
752 ret
= -E_AUTH_REQUEST
;
756 ret
= -E_AUTH_REQUEST
;
757 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
759 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
760 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
764 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
765 ret
= para_encrypt_buffer(u
->rsa
, rand_buf
, sizeof(rand_buf
),
766 (unsigned char *)buf
);
772 * We don't want to reveal our user names, so we send a
773 * challenge to the client even if the user does not exist, and
774 * fail the authentication later.
777 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
779 PARA_DEBUG_LOG("sending %zu byte challenge + rc4 keys (%u bytes)\n",
780 CHALLENGE_SIZE
, numbytes
);
781 ret
= send_bin_buffer(fd
, buf
, numbytes
);
784 /* recv challenge response */
785 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
789 PARA_DEBUG_LOG("received %zu bytes challenge response\n", ret
);
794 * The correct response is the sha1 of the first CHALLENGE_SIZE bytes
795 * of the random data.
798 if (numbytes
!= HASH_SIZE
)
800 sha1_hash((char *)rand_buf
, CHALLENGE_SIZE
, challenge_sha1
);
801 if (memcmp(challenge_sha1
, buf
, HASH_SIZE
))
803 /* auth successful */
805 PARA_INFO_LOG("good auth for %s\n", u
->name
);
806 /* init rc4 keys with the second part of the random buffer */
807 RC4_set_key(&rc4c
.recv_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
);
808 RC4_set_key(&rc4c
.send_key
, RC4_KEY_LEN
, rand_buf
+ CHALLENGE_SIZE
810 ret
= rc4_send_buffer(&rc4c
, PROCEED_MSG
);
813 ret
= read_command(&rc4c
, &command
);
814 if (ret
== -E_COMMAND_SYNTAX
)
819 cmd
= parse_cmd(command
);
822 /* valid command, check permissions */
823 ret
= check_perms(u
->perms
, cmd
);
826 /* valid command and sufficient perms */
827 argc
= split_args(command
, &argv
, "\n");
828 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
830 ret
= cmd
->handler(&rc4c
, argc
, argv
);
831 mutex_lock(mmd_mutex
);
833 mutex_unlock(mmd_mutex
);
837 rc4_send_va_buffer(&rc4c
, "%s\n", para_strerror(-ret
));
839 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
);