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"
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 stream_cipher_context
*scc
, 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 stream_cipher_context
*scc
, int argc
, char * const * argv
)
194 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
= sc_send_buffer(scc
, msg
);
207 ret
= check_sender_args(argc
, argv
, &scd
);
209 if (scd
.sender_num
< 0)
211 msg
= senders
[scd
.sender_num
].help();
212 ret
= sc_send_buffer(scc
, msg
);
217 switch (scd
.cmd_num
) {
220 assert(senders
[scd
.sender_num
].resolve_target
);
221 ret
= senders
[scd
.sender_num
].resolve_target(argv
[3], &scd
);
226 for (i
= 0; i
< 10; i
++) {
227 mutex_lock(mmd_mutex
);
228 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
229 mutex_unlock(mmd_mutex
);
233 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
234 mutex_unlock(mmd_mutex
);
237 return (i
< 10)? 1 : -E_LOCK
;
241 int com_si(struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
245 char *sender_info
= NULL
;
248 return -E_COMMAND_SYNTAX
;
249 mutex_lock(mmd_mutex
);
250 for (i
= 0; senders
[i
].name
; i
++) {
251 char *info
= senders
[i
].info();
252 sender_info
= para_strcat(sender_info
, info
);
256 ret
= sc_send_va_buffer(scc
, "version: " GIT_VERSION
"\n"
257 "up: %s\nplayed: %u\n"
260 "connections (active/accepted/total): %u/%u/%u\n"
261 "current loglevel: %s\n"
262 "supported audio formats: %s\n"
267 mmd
->active_connections
,
271 SERVER_AUDIO_FORMATS
,
274 mutex_unlock(mmd_mutex
);
281 int com_version(struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
284 return -E_COMMAND_SYNTAX
;
285 return sc_send_buffer(scc
, VERSION_TEXT("server")
286 "built: " BUILD_DATE
"\n"
287 UNAME_RS
", " CC_VERSION
"\n"
291 #define EMPTY_STATUS_ITEMS \
296 ITEM(ATTRIBUTES_BITMAP) \
297 ITEM(ATTRIBUTES_TXT) \
308 ITEM(SECONDS_TOTAL) \
320 * Write a list of audio-file related status items with empty values.
322 * This is used by vss when currently no audio file is open.
324 static char *empty_status_items(int parser_friendly
)
328 #define ITEM(x) "0004 %02x:\n"
331 #define ITEM(x) , SI_ ## x
336 #define ITEM(x) "%s:\n"
339 #define ITEM(x) ,status_item_list[SI_ ## x]
344 #undef EMPTY_STATUS_ITEMS
347 int com_stat(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
350 struct misc_meta_data tmp
, *nmmd
= &tmp
;
353 int parser_friendly
= 0;
355 para_sigaction(SIGUSR1
, dummy
);
357 for (i
= 1; i
< argc
; i
++) {
358 const char *arg
= argv
[i
];
361 if (!strcmp(arg
, "--")) {
365 if (!strncmp(arg
, "-n=", 3)) {
366 ret
= para_atoi32(arg
+ 3, &num
);
371 if (!strcmp(arg
, "-p")) {
375 return -E_COMMAND_SYNTAX
;
378 return -E_COMMAND_SYNTAX
;
381 s
= get_status(nmmd
, parser_friendly
);
382 ret
= sc_send_buffer(scc
, s
);
386 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
389 esi
= empty_status_items(parser_friendly
);
390 ret
= sc_send_buffer(scc
, esi
);
394 send_afs_status(scc
, parser_friendly
);
396 if (num
> 0 && !--num
)
400 return -E_SERVER_CRASH
;
406 static int send_list_of_commands(struct stream_cipher_context
*scc
, struct server_command
*cmd
,
411 for (i
= 1; cmd
->name
; cmd
++, i
++) {
412 char *perms
= cmd_perms_itohuman(cmd
->perms
);
413 ret
= sc_send_va_buffer(scc
, "%s\t%s\t%s\t%s\n", cmd
->name
,
424 /* returns string that must be freed by the caller */
425 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
427 struct server_command
*cmd
;
429 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
430 if (!strcmp(cmd
->name
, name
)) {
432 *handler
= para_strdup("server"); /* server commands */
435 /* not found, look for commands supported by afs */
436 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
437 if (!strcmp(cmd
->name
, name
)) {
439 *handler
= para_strdup("afs");
446 int com_help(struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
448 struct server_command
*cmd
;
449 char *perms
, *handler
;
453 /* no argument given, print list of commands */
454 if ((ret
= send_list_of_commands(scc
, server_cmds
, "server")) < 0)
456 return send_list_of_commands(scc
, afs_cmds
, "afs");
458 /* argument given for help */
459 cmd
= get_cmd_ptr(argv
[1], &handler
);
462 perms
= cmd_perms_itohuman(cmd
->perms
);
463 ret
= sc_send_va_buffer(scc
,
482 int com_hup(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
485 return -E_COMMAND_SYNTAX
;
486 kill(getppid(), SIGHUP
);
491 int com_term(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
494 return -E_COMMAND_SYNTAX
;
495 kill(getppid(), SIGTERM
);
499 int com_play(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
502 return -E_COMMAND_SYNTAX
;
503 mutex_lock(mmd_mutex
);
504 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
505 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
506 mutex_unlock(mmd_mutex
);
512 int com_stop(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
515 return -E_COMMAND_SYNTAX
;
516 mutex_lock(mmd_mutex
);
517 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
518 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
519 mmd
->new_vss_status_flags
|= VSS_NEXT
;
520 mutex_unlock(mmd_mutex
);
525 int com_pause(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
528 return -E_COMMAND_SYNTAX
;
529 mutex_lock(mmd_mutex
);
530 if (!vss_paused() && !vss_stopped()) {
532 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
533 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
535 mutex_unlock(mmd_mutex
);
540 int com_next(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
543 return -E_COMMAND_SYNTAX
;
544 mutex_lock(mmd_mutex
);
546 mmd
->new_vss_status_flags
|= VSS_NEXT
;
547 mutex_unlock(mmd_mutex
);
552 int com_nomore(__a_unused
struct stream_cipher_context
*scc
, int argc
, __a_unused
char * const * argv
)
555 return -E_COMMAND_SYNTAX
;
556 mutex_lock(mmd_mutex
);
557 if (vss_playing() || vss_paused())
558 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
559 mutex_unlock(mmd_mutex
);
564 int com_ff(__a_unused
struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
567 int ret
, backwards
= 0;
572 return -E_COMMAND_SYNTAX
;
573 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
574 return -E_COMMAND_SYNTAX
;
575 if (ret
> 1 && c
== '-')
576 backwards
= 1; /* jmp backwards */
577 mutex_lock(mmd_mutex
);
578 ret
= -E_NO_AUDIO_FILE
;
579 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
581 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
583 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
585 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
588 if (promille
> 1000) {
589 mmd
->new_vss_status_flags
|= VSS_NEXT
;
592 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
593 mmd
->new_vss_status_flags
|= VSS_REPOS
;
594 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
598 mutex_unlock(mmd_mutex
);
603 int com_jmp(__a_unused
struct stream_cipher_context
*scc
, int argc
, char * const * argv
)
609 return -E_COMMAND_SYNTAX
;
610 if (sscanf(argv
[1], "%lu", &i
) <= 0)
611 return -E_COMMAND_SYNTAX
;
612 mutex_lock(mmd_mutex
);
613 ret
= -E_NO_AUDIO_FILE
;
614 if (!mmd
->afd
.afhi
.chunks_total
)
618 PARA_INFO_LOG("jumping to %lu%%\n", i
);
619 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
620 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
621 mmd
->chunks_sent
, mmd
->offset
);
622 mmd
->new_vss_status_flags
|= VSS_REPOS
;
623 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
627 mutex_unlock(mmd_mutex
);
632 * check if perms are sufficient to exec a command having perms cmd_perms.
633 * Returns 0 if perms are sufficient, -E_PERM otherwise.
635 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
637 PARA_DEBUG_LOG("checking permissions\n");
638 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
642 * Parse first string from *cmd and lookup in table of valid commands.
643 * On error, NULL is returned.
645 static struct server_command
*parse_cmd(const char *cmdstr
)
650 sscanf(cmdstr
, "%200s%n", buf
, &n
);
654 return get_cmd_ptr(buf
, NULL
);
657 static int read_command(struct stream_cipher_context
*scc
, char **result
)
661 char *command
= NULL
;
667 ret
= sc_recv_buffer(scc
, buf
, sizeof(buf
));
673 ret
= -E_COMMAND_SYNTAX
;
674 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
676 command
= para_strcat(command
, buf
);
677 p
= strstr(command
, EOC_MSG
);
683 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
693 static void reset_signals(void)
695 para_sigaction(SIGCHLD
, SIG_IGN
);
696 para_sigaction(SIGINT
, SIG_DFL
);
697 para_sigaction(SIGTERM
, SIG_DFL
);
698 para_sigaction(SIGHUP
, SIG_DFL
);
702 * Perform user authentication and execute a command.
704 * \param fd The file descriptor to send output to.
705 * \param peername Identifies the connecting peer.
707 * Whenever para_server accepts an incoming tcp connection on
708 * the port it listens on, it forks and the resulting child
709 * calls this function.
711 * An RSA-based challenge/response is used to authenticate
712 * the peer. It that authentication succeeds, a random
713 * session key is generated and sent back to the peer,
714 * encrypted with its RSA public key. From this point on,
715 * all transfers are crypted with this session key.
717 * Next it is checked if the peer supplied a valid server command or a command
718 * for the audio file selector. If yes, and if the user has sufficient
719 * permissions to execute that command, the function calls the corresponding
720 * command handler which does argument checking and further processing.
722 * In order to cope with a DOS attacks, a timeout is set up
723 * which terminates the function if the connection was not
724 * authenticated when the timeout expires.
726 * \sa alarm(2), crypt.c, crypt.h
728 __noreturn
void handle_connect(int fd
, const char *peername
)
732 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * SESSION_KEY_LEN
];
733 unsigned char challenge_hash
[HASH_SIZE
];
735 struct server_command
*cmd
= NULL
;
737 char *p
, *command
= NULL
;
739 struct stream_cipher_context scc
= {.fd
= fd
};
742 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
743 ret
= mark_fd_blocking(fd
);
746 /* send Welcome message */
747 ret
= send_va_buffer(fd
, "This is para_server, version "
748 PACKAGE_VERSION
".\n" );
751 /* recv auth request line */
752 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
756 ret
= -E_AUTH_REQUEST
;
760 ret
= -E_AUTH_REQUEST
;
761 if (strncmp(buf
, AUTH_REQUEST_MSG
, strlen(AUTH_REQUEST_MSG
)))
763 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
764 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
768 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
769 ret
= pub_encrypt(u
->pubkey
, rand_buf
, sizeof(rand_buf
),
770 (unsigned char *)buf
);
776 * We don't want to reveal our user names, so we send a
777 * challenge to the client even if the user does not exist, and
778 * fail the authentication later.
781 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
783 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
784 CHALLENGE_SIZE
, numbytes
);
785 ret
= send_bin_buffer(fd
, buf
, numbytes
);
788 /* recv challenge response */
789 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
793 PARA_DEBUG_LOG("received %d bytes challenge response\n", ret
);
798 * The correct response is the hash of the first CHALLENGE_SIZE bytes
799 * of the random data.
802 if (numbytes
!= HASH_SIZE
)
804 hash_function((char *)rand_buf
, CHALLENGE_SIZE
, challenge_hash
);
805 if (memcmp(challenge_hash
, buf
, HASH_SIZE
))
807 /* auth successful */
809 PARA_INFO_LOG("good auth for %s\n", u
->name
);
810 /* init stream cipher keys with the second part of the random buffer */
811 scc
.recv
= sc_new(rand_buf
+ CHALLENGE_SIZE
, SESSION_KEY_LEN
);
812 scc
.send
= sc_new(rand_buf
+ CHALLENGE_SIZE
+ SESSION_KEY_LEN
, SESSION_KEY_LEN
);
813 ret
= sc_send_buffer(&scc
, PROCEED_MSG
);
816 ret
= read_command(&scc
, &command
);
817 if (ret
== -E_COMMAND_SYNTAX
)
822 cmd
= parse_cmd(command
);
825 /* valid command, check permissions */
826 ret
= check_perms(u
->perms
, cmd
);
829 /* valid command and sufficient perms */
830 ret
= create_argv(command
, "\n", &argv
);
834 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
836 ret
= cmd
->handler(&scc
, argc
, argv
);
838 mutex_lock(mmd_mutex
);
840 mutex_unlock(mmd_mutex
);
844 sc_send_va_buffer(&scc
, "%s\n", para_strerror(-ret
));
846 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
851 mutex_lock(mmd_mutex
);
852 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
854 mmd
->active_connections
--;
855 mutex_unlock(mmd_mutex
);
856 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);