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>
17 #include "server.cmdline.h"
30 #include "user_list.h"
31 #include "server_command_list.h"
32 #include "afs_command_list.h"
36 /** Commands including options must be shorter than this. */
37 #define MAX_COMMAND_LEN 32768
39 static RC4_KEY rc4_recv_key
;
40 static RC4_KEY rc4_send_key
;
41 static unsigned char rc4_buf
[2 * RC4_KEY_LEN
];
44 extern struct misc_meta_data
*mmd
;
45 extern struct sender senders
[];
47 static void dummy(__a_unused
int s
)
51 static void mmd_dup(struct misc_meta_data
*new_mmd
)
53 mutex_lock(mmd_mutex
);
55 mutex_unlock(mmd_mutex
);
59 * Compute human readable string containing vss status for given integer value.
61 * We don't want to use vss_playing() and friends here because we take a
62 * snapshot of the mmd struct and use the copy for computing the state of the
63 * vss. If the real data were used, we would take the mmd lock for a rather
64 * long time or risk to get an inconsistent view.
66 static char *vss_status_tohuman(unsigned int flags
)
68 if (flags
& VSS_PLAYING
)
69 return para_strdup("playing");
71 return para_strdup("stopped");
72 return para_strdup("paused");
76 * return human readable permission string. Never returns NULL.
78 static char *cmd_perms_itohuman(unsigned int perms
)
80 char *msg
= para_malloc(5 * sizeof(char));
82 msg
[0] = perms
& AFS_READ
? 'a' : '-';
83 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
84 msg
[2] = perms
& VSS_READ
? 'v' : '-';
85 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
93 static char *vss_get_status_flags(unsigned int flags
)
95 char *msg
= para_malloc(5 * sizeof(char));
97 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
98 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
99 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
100 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
105 static char *get_status(struct misc_meta_data
*nmmd
)
107 char *ret
, mtime
[30] = "";
108 char *status
, *flags
; /* vss status info */
109 char *ut
= uptime_str();
110 long offset
= (nmmd
->offset
+ 500) / 1000;
111 struct timeval current_time
;
114 /* report real status */
115 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
116 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
117 if (nmmd
->size
) { /* parent currently has an audio file open */
118 localtime_r(&nmmd
->mtime
, &mtime_tm
);
119 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
121 gettimeofday(¤t_time
, NULL
);
123 "%s: %zu\n" /* file size */
124 "%s: %s\n" /* mtime */
125 "%s: %s\n" /* status */
126 "%s: %s\n" /* status flags */
127 "%s: %li\n" /* offset */
128 "%s: %s\n" /* afs mode */
129 "%s: %lu.%lu\n" /* stream start */
130 "%s: %lu.%lu\n" /* current server time */
131 "%s", /* afs status info */
132 status_item_list
[SI_FILE_SIZE
], nmmd
->size
/ 1024,
133 status_item_list
[SI_MTIME
], mtime
,
134 status_item_list
[SI_STATUS
], status
,
135 status_item_list
[SI_STATUS_FLAGS
], flags
,
137 status_item_list
[SI_OFFSET
], offset
,
138 status_item_list
[SI_AFS_MODE
], mmd
->afs_mode_string
,
140 status_item_list
[SI_STREAM_START
],
141 (long unsigned)nmmd
->stream_start
.tv_sec
,
142 (long unsigned)nmmd
->stream_start
.tv_usec
,
143 status_item_list
[SI_CURRENT_TIME
],
144 (long unsigned)current_time
.tv_sec
,
145 (long unsigned)current_time
.tv_usec
,
147 nmmd
->afd
.verbose_ls_output
156 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
159 /* this has to match sender.h */
160 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
162 scd
->sender_num
= -1;
164 return -E_COMMAND_SYNTAX
;
165 for (i
= 0; senders
[i
].name
; i
++)
166 if (!strcmp(senders
[i
].name
, argv
[1]))
168 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
169 if (!senders
[i
].name
)
170 return -E_COMMAND_SYNTAX
;
172 for (i
= 0; subcmds
[i
]; i
++)
173 if (!strcmp(subcmds
[i
], argv
[2]))
176 return -E_COMMAND_SYNTAX
;
178 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
179 return -E_SENDER_CMD
;
180 switch (scd
->cmd_num
) {
184 return -E_COMMAND_SYNTAX
;
188 if (argc
!= 4 && argc
!= 5)
189 return -E_COMMAND_SYNTAX
;
190 if (!is_valid_ipv4_address(argv
[3]))
191 return -E_COMMAND_SYNTAX
;
194 scd
->netmask
= atoi(argv
[4]);
195 if (scd
->netmask
< 0 || scd
->netmask
> 32)
196 return -E_COMMAND_SYNTAX
;
198 strncpy(scd
->host
, argv
[3], sizeof(scd
->host
));
203 return -E_COMMAND_SYNTAX
;
204 return parse_fec_url(argv
[3], scd
);
206 return -E_COMMAND_SYNTAX
;
211 int com_sender(int fd
, int argc
, char * const * argv
)
214 struct sender_command_data scd
;
218 for (i
= 0; senders
[i
].name
; i
++) {
219 char *tmp
= make_message("%s%s\n",
220 msg
? msg
: "", senders
[i
].name
);
224 ret
= send_buffer(fd
, msg
);
228 ret
= check_sender_args(argc
, argv
, &scd
);
231 if (scd
.sender_num
< 0)
233 msg
= senders
[scd
.sender_num
].help();
234 ret
= send_buffer(fd
, msg
);
238 for (i
= 0; i
< 10; i
++) {
239 mutex_lock(mmd_mutex
);
240 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
241 mutex_unlock(mmd_mutex
);
245 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
246 mutex_unlock(mmd_mutex
);
249 return (i
< 10)? 1 : -E_LOCK
;
253 int com_si(int fd
, int argc
, __a_unused
char * const * argv
)
257 char *sender_info
= NULL
, *sender_list
= NULL
;
260 return -E_COMMAND_SYNTAX
;
261 mutex_lock(mmd_mutex
);
262 for (i
= 0; senders
[i
].name
; i
++) {
263 char *info
= senders
[i
].info();
264 sender_info
= para_strcat(sender_info
, info
);
266 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
267 sender_list
= para_strcat(sender_list
, " ");
270 ret
= send_va_buffer(fd
, "up: %s\nplayed: %u\n"
273 "connections (active/accepted/total): %u/%u/%u\n"
274 "current loglevel: %s\n"
275 "supported audio formats: %s\n"
276 "supported senders: %s\n"
281 mmd
->active_connections
,
285 supported_audio_formats(),
289 mutex_unlock(mmd_mutex
);
297 int com_version(int fd
, int argc
, __a_unused
char * const * argv
)
300 return -E_COMMAND_SYNTAX
;
301 return send_buffer(fd
, VERSION_TEXT("server")
302 "built: " BUILD_DATE
"\n"
303 UNAME_RS
", " CC_VERSION
"\n"
308 int com_stat(int fd
, int argc
, char * const * argv
)
310 int ret
, num
= 0;/* status will be printed that many
311 * times. num <= 0 means: print forever
313 struct misc_meta_data tmp
, *nmmd
= &tmp
;
316 ret
= para_sigaction(SIGUSR1
, dummy
);
325 s
= get_status(nmmd
);
326 ret
= send_buffer(fd
, s
);
331 if (num
> 0 && !--num
)
335 return -E_SERVER_CRASH
;
341 static int send_list_of_commands(int fd
, struct server_command
*cmd
,
346 for (i
= 1; cmd
->name
; cmd
++, i
++) {
347 char *perms
= cmd_perms_itohuman(cmd
->perms
);
348 ret
= send_va_buffer(fd
, "%s\t%s\t%s\t%s\n", cmd
->name
,
359 /* returns string that must be freed by the caller */
360 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
362 struct server_command
*cmd
;
364 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
365 if (!strcmp(cmd
->name
, name
)) {
367 *handler
= para_strdup("server"); /* server commands */
370 /* not found, look for commands supported by afs */
371 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
372 if (!strcmp(cmd
->name
, name
)) {
374 *handler
= para_strdup("afs");
381 int com_help(int fd
, int argc
, char * const * argv
)
383 struct server_command
*cmd
;
384 char *perms
, *handler
;
388 /* no argument given, print list of commands */
389 if ((ret
= send_list_of_commands(fd
, server_cmds
, "server")) < 0)
391 return send_list_of_commands(fd
, afs_cmds
, "afs");
393 /* argument given for help */
394 cmd
= get_cmd_ptr(argv
[1], &handler
);
399 perms
= cmd_perms_itohuman(cmd
->perms
);
400 ret
= send_va_buffer(fd
,
419 int com_hup(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
422 return -E_COMMAND_SYNTAX
;
423 kill(getppid(), SIGHUP
);
428 int com_term(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
431 return -E_COMMAND_SYNTAX
;
432 kill(getppid(), SIGTERM
);
436 int com_play(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
439 return -E_COMMAND_SYNTAX
;
440 mutex_lock(mmd_mutex
);
441 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
442 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
443 mutex_unlock(mmd_mutex
);
449 int com_stop(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
452 return -E_COMMAND_SYNTAX
;
453 mutex_lock(mmd_mutex
);
454 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
455 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
456 mmd
->new_vss_status_flags
|= VSS_NEXT
;
457 mutex_unlock(mmd_mutex
);
462 int com_pause(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
465 return -E_COMMAND_SYNTAX
;
466 mutex_lock(mmd_mutex
);
467 if (!vss_paused() && !vss_stopped()) {
469 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
470 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
472 mutex_unlock(mmd_mutex
);
477 int com_next(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
480 return -E_COMMAND_SYNTAX
;
481 mutex_lock(mmd_mutex
);
483 mmd
->new_vss_status_flags
|= VSS_NEXT
;
484 mutex_unlock(mmd_mutex
);
489 int com_nomore(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
492 return -E_COMMAND_SYNTAX
;
493 mutex_lock(mmd_mutex
);
494 if (vss_playing() || vss_paused())
495 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
496 mutex_unlock(mmd_mutex
);
501 int com_ff(__a_unused
int fd
, int argc
, char * const * argv
)
504 int ret
, backwards
= 0;
509 return -E_COMMAND_SYNTAX
;
510 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
511 return -E_COMMAND_SYNTAX
;
512 if (ret
> 1 && c
== '-')
513 backwards
= 1; /* jmp backwards */
514 mutex_lock(mmd_mutex
);
515 ret
= -E_NO_AUDIO_FILE
;
516 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
518 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
520 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
522 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
525 if (promille
> 1000) {
526 mmd
->new_vss_status_flags
|= VSS_NEXT
;
529 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
530 mmd
->new_vss_status_flags
|= VSS_REPOS
;
531 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
535 mutex_unlock(mmd_mutex
);
540 int com_jmp(__a_unused
int fd
, int argc
, char * const * argv
)
546 return -E_COMMAND_SYNTAX
;
547 if (sscanf(argv
[1], "%lu", &i
) <= 0)
548 return -E_COMMAND_SYNTAX
;
549 mutex_lock(mmd_mutex
);
550 ret
= -E_NO_AUDIO_FILE
;
551 if (!mmd
->afd
.afhi
.chunks_total
)
555 PARA_INFO_LOG("jumping to %lu%%\n", i
);
556 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
557 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
558 mmd
->chunks_sent
, mmd
->offset
);
559 mmd
->new_vss_status_flags
|= VSS_REPOS
;
560 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
564 mutex_unlock(mmd_mutex
);
569 * check if perms are sufficient to exec a command having perms cmd_perms.
570 * Returns 0 if perms are sufficient, -E_PERM otherwise.
572 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
574 PARA_DEBUG_LOG("checking permissions\n");
575 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
579 * Parse first string from *cmd and lookup in table of valid commands.
580 * On error, NULL is returned.
582 static struct server_command
*parse_cmd(const char *cmdstr
)
587 sscanf(cmdstr
, "%200s%n", buf
, &n
);
591 return get_cmd_ptr(buf
, NULL
);
594 static void init_rc4_keys(void)
598 for (i
= 0; i
< 2 * RC4_KEY_LEN
; i
++)
599 rc4_buf
[i
] = para_random(256);
600 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
601 (unsigned char) rc4_buf
[0],
602 (unsigned char) rc4_buf
[RC4_KEY_LEN
]);
603 RC4_set_key(&rc4_recv_key
, RC4_KEY_LEN
, rc4_buf
);
604 RC4_set_key(&rc4_send_key
, RC4_KEY_LEN
, rc4_buf
+ RC4_KEY_LEN
);
607 static void rc4_recv(unsigned long len
, const unsigned char *indata
,
608 unsigned char *outdata
, __a_unused
void *private_data
)
610 RC4(&rc4_recv_key
, len
, indata
, outdata
);
613 static void rc4_send(unsigned long len
, const unsigned char *indata
,
614 unsigned char *outdata
, __a_unused
void *private_data
)
616 RC4(&rc4_send_key
, len
, indata
, outdata
);
619 static int read_command(int fd
, char **result
)
623 char *command
= NULL
;
629 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
635 ret
= -E_COMMAND_SYNTAX
;
636 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
638 command
= para_strcat(command
, buf
);
639 p
= strstr(command
, EOC_MSG
);
645 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
655 static int reset_signals(void)
657 int ret
= para_sigaction(SIGCHLD
, SIG_IGN
);
661 ret
= para_sigaction(SIGINT
, SIG_DFL
);
664 ret
= para_sigaction(SIGTERM
, SIG_DFL
);
667 ret
= para_sigaction(SIGHUP
, SIG_DFL
);
674 * Perform user authentication and execute a command.
676 * \param fd The file descriptor to send output to.
677 * \param peername Identifies the connecting peer.
679 * Whenever para_server accepts an incoming tcp connection on
680 * the port it listens on, it forks and the resulting child
681 * calls this function.
683 * An RSA-based challenge/response is used to authenticate
684 * the peer. It that authentication succeeds, a random RC4
685 * session key is generated and sent back to the peer,
686 * encrypted with its RSA public key. From this point on,
687 * all transfers are crypted with this session key.
689 * Next it is checked if the peer supplied a valid server command or a command
690 * for the audio file selector. If yes, and if the user has sufficient
691 * permissions to execute that command, the function calls the corresponding
692 * command handler which does argument checking and further processing.
694 * In order to cope with a DOS attacks, a timeout is set up
695 * which terminates the function if the connection was not
696 * authenticated when the timeout expires.
698 * \sa alarm(2), rc4(3), crypt.c, crypt.h
700 __noreturn
void handle_connect(int fd
, const char *peername
)
702 int ret
, argc
, use_rc4
= 0;
704 unsigned char crypt_buf
[MAXLINE
];
706 struct server_command
*cmd
= NULL
;
707 long unsigned challenge_nr
, chall_response
;
709 char *p
, *command
= NULL
;
712 ret
= reset_signals();
715 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
716 ret
= mark_fd_blocking(fd
);
719 challenge_nr
= random();
720 /* send Welcome message */
721 ret
= send_va_buffer(fd
, "This is para_server, version "
722 PACKAGE_VERSION
".\n" );
725 /* recv auth request line */
726 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
735 if (strncmp(buf
, "auth ", 5))
738 if (numbytes
< 9 || strncmp(buf
, "auth rc4 ", 9))
739 p
= buf
+ 5; /* client version < 0.2.6 */
741 p
= buf
+ 9; /* client version >= 0.2.6 */
744 PARA_DEBUG_LOG("received %s request for user %s\n",
745 use_rc4
? "rc4" : "auth", p
);
750 ret
= para_encrypt_challenge(u
->rsa
, challenge_nr
, crypt_buf
);
754 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes
);
755 /* We can't use send_buffer here since buf may contain null bytes */
756 ret
= send_bin_buffer(fd
,(char *) crypt_buf
, numbytes
);
759 /* recv decrypted number */
760 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
767 if (sscanf(buf
, CHALLENGE_RESPONSE_MSG
"%lu", &chall_response
) < 1
768 || chall_response
!= challenge_nr
)
770 /* auth successful, send 'Proceed' message */
771 PARA_INFO_LOG("good auth for %s (%lu)\n", u
->name
, challenge_nr
);
772 sprintf(buf
, "%s", PROCEED_MSG
);
775 ret
= para_encrypt_buffer(u
->rsa
, rc4_buf
, 2 * RC4_KEY_LEN
,
776 (unsigned char *)buf
+ PROCEED_MSG_LEN
+ 1);
779 numbytes
= ret
+ strlen(PROCEED_MSG
) + 1;
781 numbytes
= strlen(buf
);
782 ret
= send_bin_buffer(fd
, buf
, numbytes
);
786 enable_crypt(fd
, rc4_recv
, rc4_send
, NULL
);
787 ret
= read_command(fd
, &command
);
788 if (ret
== -E_COMMAND_SYNTAX
)
793 cmd
= parse_cmd(command
);
796 /* valid command, check permissions */
797 ret
= check_perms(u
->perms
, cmd
);
800 /* valid command and sufficient perms */
802 argc
= split_args(command
, &argv
, "\n");
803 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
805 ret
= cmd
->handler(fd
, argc
, argv
);
806 mutex_lock(mmd_mutex
);
808 free(mmd
->afd
.afhi
.info_string
);
809 free(mmd
->afd
.afhi
.chunk_table
);
810 mutex_unlock(mmd_mutex
);
814 send_va_buffer(fd
, "%s\n", para_strerror(-ret
));
816 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
820 mutex_lock(mmd_mutex
);
821 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
823 mmd
->active_connections
--;
824 mutex_unlock(mmd_mutex
);
825 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);