2 * Copyright (C) 1997-2007 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"
29 #include "user_list.h"
30 #include "server_command_list.h"
31 #include "afs_command_list.h"
33 /** Commands including options must be shorter than this. */
34 #define MAX_COMMAND_LEN 32768
36 static RC4_KEY rc4_recv_key
;
37 static RC4_KEY rc4_send_key
;
38 static unsigned char rc4_buf
[2 * RC4_KEY_LEN
];
40 extern struct misc_meta_data
*mmd
;
41 extern struct sender senders
[];
43 static void dummy(__a_unused
int s
)
46 static void mmd_dup(struct misc_meta_data
*new_mmd
)
54 * compute human readable string containing
55 * vss status for given integer value
57 static char *vss_status_tohuman(unsigned int flags
)
59 if (flags
& VSS_PLAYING
)
60 return para_strdup("playing");
61 else if (flags
& VSS_NEXT
)
62 return para_strdup("stopped");
64 return para_strdup("paused");
68 * return human readable permission string. Never returns NULL.
70 static char *cmd_perms_itohuman(unsigned int perms
)
72 char *msg
= para_malloc(5 * sizeof(char));
74 msg
[0] = perms
& AFS_READ
? 'a' : '-';
75 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
76 msg
[2] = perms
& VSS_READ
? 'v' : '-';
77 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
85 static char *vss_get_status_flags(unsigned int flags
)
87 char *msg
= para_malloc(5 * sizeof(char));
89 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
90 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
91 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
92 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
97 static char *get_status(struct misc_meta_data
*nmmd
)
99 char *ret
, mtime
[30] = "";
100 char *status
, *flags
; /* vss status info */
101 char *ut
= uptime_str();
102 long offset
= (nmmd
->offset
+ 500) / 1000;
106 /* report real status */
107 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
108 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
109 if (nmmd
->size
) { /* parent currently has an audio file open */
110 localtime_r(&nmmd
->mtime
, &mtime_tm
);
111 strftime(mtime
, 29, "%a %b %d %Y", &mtime_tm
);
113 gettimeofday(&now
, NULL
);
115 "%s: %zu\n" /* file size */
116 "%s: %s\n" /* mtime */
117 "%s: %s\n" /* status */
118 "%s: %s\n" /* status flags */
119 "%s: %li\n" /* offset */
120 "%s: %s\n" /* afs mode */
121 "%s: %s\n" /* server uptime */
122 "%s: %lu.%lu\n" /* stream start */
123 "%s: %lu.%lu\n" /* current server time */
124 "%s\n", /* afs status info */
125 status_item_list
[SI_FILE_SIZE
], nmmd
->size
/ 1024,
126 status_item_list
[SI_MTIME
], mtime
,
127 status_item_list
[SI_STATUS
], status
,
128 status_item_list
[SI_STATUS_FLAGS
], flags
,
130 status_item_list
[SI_OFFSET
], offset
,
131 status_item_list
[SI_AFS_MODE
], mmd
->afs_mode_string
,
133 status_item_list
[SI_UPTIME
], ut
,
134 status_item_list
[SI_STREAM_START
],
135 (long unsigned)nmmd
->stream_start
.tv_sec
,
136 (long unsigned)nmmd
->stream_start
.tv_usec
,
137 status_item_list
[SI_CURRENT_TIME
],
138 (long unsigned)now
.tv_sec
,
139 (long unsigned)now
.tv_usec
,
141 nmmd
->afd
.verbose_ls_output
150 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
153 /* this has to match sender.h */
154 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
156 scd
->sender_num
= -1;
158 return -E_COMMAND_SYNTAX
;
159 for (i
= 0; senders
[i
].name
; i
++)
160 if (!strcmp(senders
[i
].name
, argv
[1]))
162 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
163 if (!senders
[i
].name
)
164 return -E_COMMAND_SYNTAX
;
166 for (i
= 0; subcmds
[i
]; i
++)
167 if (!strcmp(subcmds
[i
], argv
[2]))
170 return -E_COMMAND_SYNTAX
;
173 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
]) {
175 return -E_SENDER_CMD
;
178 switch (scd
->cmd_num
) {
182 return -E_COMMAND_SYNTAX
;
186 if (argc
!= 4 && argc
!= 5)
187 return -E_COMMAND_SYNTAX
;
188 if (!inet_pton(AF_INET
, argv
[3], &scd
->addr
))
189 return -E_COMMAND_SYNTAX
;
192 scd
->netmask
= atoi(argv
[4]);
193 if (scd
->netmask
< 0 || scd
->netmask
> 32)
194 return -E_COMMAND_SYNTAX
;
199 if (argc
!= 4 && argc
!= 5)
200 return -E_COMMAND_SYNTAX
;
201 if (!inet_pton(AF_INET
, argv
[3], &scd
->addr
))
202 return -E_COMMAND_SYNTAX
;
205 scd
->port
= atoi(argv
[4]);
206 if (scd
->port
< 0 || scd
->port
> 65535)
207 return -E_COMMAND_SYNTAX
;
211 return -E_COMMAND_SYNTAX
;
216 int com_sender(int fd
, int argc
, char * const * argv
)
219 struct sender_command_data scd
;
223 for (i
= 0; senders
[i
].name
; i
++) {
224 char *tmp
= make_message("%s%s\n",
225 msg
? msg
: "", senders
[i
].name
);
229 ret
= send_buffer(fd
, msg
);
233 ret
= check_sender_args(argc
, argv
, &scd
);
236 if (scd
.sender_num
< 0)
238 msg
= senders
[scd
.sender_num
].help();
239 send_buffer(fd
, msg
);
243 for (i
= 0; i
< 10; i
++) {
245 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
250 mmd
->sender_cmd_data
= scd
;
254 return (i
< 10)? 1 : -E_LOCK
;
258 int com_si(int fd
, int argc
, __a_unused
char * const * argv
)
262 char *sender_info
= NULL
, *sender_list
= NULL
;
265 return -E_COMMAND_SYNTAX
;
267 for (i
= 0; senders
[i
].name
; i
++) {
268 char *info
= senders
[i
].info();
269 sender_info
= para_strcat(sender_info
, info
);
271 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
272 sender_list
= para_strcat(sender_list
, " ");
275 ret
= send_va_buffer(fd
, "up: %s\nplayed: %u\n"
277 "connections (active/accepted/total): %u/%u/%u\n"
278 "current loglevel: %i\n"
279 "supported audio formats: %s\n"
280 "supported senders: %s\n"
284 mmd
->active_connections
,
288 supported_audio_formats(),
300 int com_version(int fd
, int argc
, __a_unused
char * const * argv
)
303 return -E_COMMAND_SYNTAX
;
304 return send_buffer(fd
, VERSION_TEXT("server")
305 "built: " BUILD_DATE
"\n"
306 SYSTEM
", " CC_VERSION
"\n"
311 int com_stat(int fd
, int argc
, char * const * argv
)
313 int ret
, num
= 0;/* status will be printed that many
314 * times. num <= 0 means: print forever
316 struct misc_meta_data tmp
, *nmmd
= &tmp
;
319 signal(SIGUSR1
, dummy
);
326 s
= get_status(nmmd
);
327 ret
= send_buffer(fd
, s
);
336 return -E_SERVER_CRASH
;
342 static int send_list_of_commands(int fd
, struct server_command
*cmd
,
347 for (i
= 1; cmd
->name
; cmd
++, i
++) {
348 char *perms
= cmd_perms_itohuman(cmd
->perms
);
349 ret
= send_va_buffer(fd
, "%s\t%s\t%s\t%s\n", cmd
->name
,
360 /* returns string that must be freed by the caller */
361 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
363 struct server_command
*cmd
;
365 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
366 if (!strcmp(cmd
->name
, name
)) {
368 *handler
= para_strdup("server"); /* server commands */
371 /* not found, look for commands supported by afs */
372 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
373 if (!strcmp(cmd
->name
, name
)) {
375 *handler
= para_strdup("afs");
382 int com_help(int fd
, int argc
, char * const * argv
)
384 struct server_command
*cmd
;
385 char *perms
, *handler
;
389 /* no argument given, print list of commands */
390 if ((ret
= send_list_of_commands(fd
, server_cmds
, "server")) < 0)
392 return send_list_of_commands(fd
, afs_cmds
, "afs");
394 /* argument given for help */
395 cmd
= get_cmd_ptr(argv
[1], &handler
);
400 perms
= cmd_perms_itohuman(cmd
->perms
);
401 ret
= send_va_buffer(fd
,
420 int com_hup(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
423 return -E_COMMAND_SYNTAX
;
424 kill(getppid(), SIGHUP
);
429 int com_term(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
432 return -E_COMMAND_SYNTAX
;
433 kill(getppid(), SIGTERM
);
437 int com_play(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
440 return -E_COMMAND_SYNTAX
;
442 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
443 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
450 int com_stop(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
453 return -E_COMMAND_SYNTAX
;
455 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
456 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
457 mmd
->new_vss_status_flags
|= VSS_NEXT
;
463 int com_pause(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
466 return -E_COMMAND_SYNTAX
;
470 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
471 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
477 int com_next(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
480 return -E_COMMAND_SYNTAX
;
483 mmd
->new_vss_status_flags
|= VSS_NEXT
;
489 int com_nomore(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
492 return -E_COMMAND_SYNTAX
;
494 if (vss_playing() || vss_paused())
495 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
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 */
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
;
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
;
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
;
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("%s", "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
;
656 * perform user authentication and execute a command
658 * \param fd the file descriptor to send output to
659 * \param addr socket address info of peer
661 * \return EXIT_SUCCESS or EXIT_FAILURE
663 * Whenever para_server accepts an incoming tcp connection on
664 * the port it listens on, it forks and the resulting child
665 * calls this function.
667 * An RSA-based challenge/response is used to authenticate
668 * the peer. It that authentication succeeds, a random RC4
669 * session key is generated and sent back to the peer,
670 * encrypted with its RSA public key. From this point on,
671 * all transfers are crypted with this session key.
673 * Next it is checked if the peer supplied a valid server command or a command
674 * for the audio file selector. If yes, and if the user has sufficient
675 * permissions to execute that command, the function calls the corresponding
676 * command handler which does argument checking and further processing.
678 * In order to cope with a DOS attacks, a timeout is set up
679 * which terminates the function if the connection was not
680 * authenticated when the timeout expires.
682 * \sa alarm(2), rc4(3), crypt.c, crypt.h
684 int handle_connect(int fd
, struct sockaddr_in
*addr
)
686 int ret
, argc
, use_rc4
= 0;
688 unsigned char crypt_buf
[MAXLINE
];
690 struct server_command
*cmd
= NULL
;
691 long unsigned challenge_nr
, chall_response
;
693 char *p
, *command
= NULL
;
696 signal(SIGCHLD
, SIG_IGN
);
697 signal(SIGINT
, SIG_DFL
);
698 signal(SIGTERM
, SIG_DFL
);
699 signal(SIGHUP
, SIG_DFL
);
700 signal(SIGUSR1
, SIG_IGN
);
702 challenge_nr
= random();
703 /* send Welcome message */
704 ret
= send_va_buffer(fd
, "This is para_server, version "
705 PACKAGE_VERSION
".\n" );
708 /* recv auth request line */
709 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
718 if (strncmp(buf
, "auth ", 5))
721 if (numbytes
< 9 || strncmp(buf
, "auth rc4 ", 9))
722 p
= buf
+ 5; /* client version < 0.2.6 */
724 p
= buf
+ 9; /* client version >= 0.2.6 */
727 PARA_DEBUG_LOG("received %s request for user %s\n",
728 use_rc4
? "rc4" : "auth", p
);
733 ret
= para_encrypt_challenge(u
->rsa
, challenge_nr
, crypt_buf
);
737 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes
);
738 /* We can't use send_buffer here since buf may contain null bytes */
739 ret
= send_bin_buffer(fd
,(char *) crypt_buf
, numbytes
);
742 /* recv decrypted number */
743 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
750 if (sscanf(buf
, CHALLENGE_RESPONSE_MSG
"%lu", &chall_response
) < 1
751 || chall_response
!= challenge_nr
)
753 /* auth successful, send 'Proceed' message */
754 PARA_INFO_LOG("good auth for %s (%lu)\n", u
->name
, challenge_nr
);
755 sprintf(buf
, "%s", PROCEED_MSG
);
758 ret
= para_encrypt_buffer(u
->rsa
, rc4_buf
, 2 * RC4_KEY_LEN
,
759 (unsigned char *)buf
+ PROCEED_MSG_LEN
+ 1);
762 numbytes
= ret
+ strlen(PROCEED_MSG
) + 1;
764 numbytes
= strlen(buf
);
765 ret
= send_bin_buffer(fd
, buf
, numbytes
);
769 enable_crypt(fd
, rc4_recv
, rc4_send
, NULL
);
770 ret
= read_command(fd
, &command
);
774 cmd
= parse_cmd(command
);
777 /* valid command, check permissions */
778 ret
= check_perms(u
->perms
, cmd
);
781 /* valid command and sufficient perms */
783 argc
= split_args(command
, &argv
, "\n");
787 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
788 inet_ntoa(addr
->sin_addr
));
789 ret
= cmd
->handler(fd
, argc
, argv
);
795 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret
));
796 if (ret
!= -E_SEND
&& ret
!= -E_RECV
)
797 send_va_buffer(fd
, "%s\n", PARA_STRERROR(-ret
));
803 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
805 mmd
->active_connections
--;