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 const char *status_item_list
[NUM_STAT_ITEMS
];
41 extern struct misc_meta_data
*mmd
;
42 extern struct sender senders
[];
44 static void dummy(__a_unused
int s
)
47 static void mmd_dup(struct misc_meta_data
*new_mmd
)
55 * compute human readable string containing
56 * vss status for given integer value
58 static char *vss_status_tohuman(unsigned int flags
)
60 if (flags
& VSS_PLAYING
)
61 return para_strdup("playing");
62 else if (flags
& VSS_NEXT
)
63 return para_strdup("stopped");
65 return para_strdup("paused");
69 * return human readable permission string. Never returns NULL.
71 static char *cmd_perms_itohuman(unsigned int perms
)
73 char *msg
= para_malloc(5 * sizeof(char));
75 msg
[0] = perms
& AFS_READ
? 'a' : '-';
76 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
77 msg
[2] = perms
& VSS_READ
? 'v' : '-';
78 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
86 static char *vss_get_status_flags(unsigned int flags
)
88 char *msg
= para_malloc(5 * sizeof(char));
90 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
91 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
92 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
93 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
98 static char *get_status(struct misc_meta_data
*nmmd
)
100 char *ret
, mtime
[30] = "";
101 char *status
, *flags
; /* vss status info */
102 char *ut
= uptime_str();
103 long offset
= (nmmd
->offset
+ 500) / 1000;
107 /* report real status */
108 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
109 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
110 if (nmmd
->size
) { /* parent currently has an audio file open */
111 localtime_r(&nmmd
->mtime
, &mtime_tm
);
112 strftime(mtime
, 29, "%a %b %d %Y", &mtime_tm
);
114 gettimeofday(&now
, NULL
);
116 "%s: %zu\n" /* file size */
117 "%s: %s\n" /* mtime */
118 "%s: %s\n" /* status */
119 "%s: %s\n" /* status flags */
120 "%s: %li\n" /* offset */
121 "%s: %s\n" /* afs mode */
122 "%s: %s\n" /* server uptime */
123 "%s: %lu.%lu\n" /* stream start */
124 "%s: %lu.%lu\n" /* current server time */
125 "%s\n", /* afs status info */
126 status_item_list
[SI_FILE_SIZE
], nmmd
->size
/ 1024,
127 status_item_list
[SI_MTIME
], mtime
,
128 status_item_list
[SI_STATUS
], status
,
129 status_item_list
[SI_STATUS_FLAGS
], flags
,
131 status_item_list
[SI_OFFSET
], offset
,
132 status_item_list
[SI_AFS_MODE
], mmd
->afs_mode_string
,
134 status_item_list
[SI_UPTIME
], ut
,
135 status_item_list
[SI_STREAM_START
],
136 (long unsigned)nmmd
->stream_start
.tv_sec
,
137 (long unsigned)nmmd
->stream_start
.tv_usec
,
138 status_item_list
[SI_CURRENT_TIME
],
139 (long unsigned)now
.tv_sec
,
140 (long unsigned)now
.tv_usec
,
142 nmmd
->afd
.verbose_ls_output
151 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
154 /* this has to match sender.h */
155 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
157 scd
->sender_num
= -1;
159 return -E_COMMAND_SYNTAX
;
160 for (i
= 0; senders
[i
].name
; i
++)
161 if (!strcmp(senders
[i
].name
, argv
[1]))
163 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
164 if (!senders
[i
].name
)
165 return -E_COMMAND_SYNTAX
;
167 for (i
= 0; subcmds
[i
]; i
++)
168 if (!strcmp(subcmds
[i
], argv
[2]))
171 return -E_COMMAND_SYNTAX
;
174 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
]) {
176 return -E_SENDER_CMD
;
179 switch (scd
->cmd_num
) {
183 return -E_COMMAND_SYNTAX
;
187 if (argc
!= 4 && argc
!= 5)
188 return -E_COMMAND_SYNTAX
;
189 if (!inet_pton(AF_INET
, argv
[3], &scd
->addr
))
190 return -E_COMMAND_SYNTAX
;
193 scd
->netmask
= atoi(argv
[4]);
194 if (scd
->netmask
< 0 || scd
->netmask
> 32)
195 return -E_COMMAND_SYNTAX
;
200 if (argc
!= 4 && argc
!= 5)
201 return -E_COMMAND_SYNTAX
;
202 if (!inet_pton(AF_INET
, argv
[3], &scd
->addr
))
203 return -E_COMMAND_SYNTAX
;
206 scd
->port
= atoi(argv
[4]);
207 if (scd
->port
< 0 || scd
->port
> 65535)
208 return -E_COMMAND_SYNTAX
;
212 return -E_COMMAND_SYNTAX
;
217 int com_sender(int fd
, int argc
, char * const * argv
)
220 struct sender_command_data scd
;
224 for (i
= 0; senders
[i
].name
; i
++) {
225 char *tmp
= make_message("%s%s\n",
226 msg
? msg
: "", senders
[i
].name
);
230 ret
= send_buffer(fd
, msg
);
234 ret
= check_sender_args(argc
, argv
, &scd
);
237 if (scd
.sender_num
< 0)
239 msg
= senders
[scd
.sender_num
].help();
240 send_buffer(fd
, msg
);
244 for (i
= 0; i
< 10; i
++) {
246 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
251 mmd
->sender_cmd_data
= scd
;
255 return (i
< 10)? 1 : -E_LOCK
;
259 int com_si(int fd
, int argc
, __a_unused
char * const * argv
)
263 char *sender_info
= NULL
, *sender_list
= NULL
;
266 return -E_COMMAND_SYNTAX
;
268 for (i
= 0; senders
[i
].name
; i
++) {
269 char *info
= senders
[i
].info();
270 sender_info
= para_strcat(sender_info
, info
);
272 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
273 sender_list
= para_strcat(sender_list
, " ");
276 ret
= send_va_buffer(fd
, "up: %s\nplayed: %u\n"
278 "connections (active/accepted/total): %u/%u/%u\n"
279 "current loglevel: %i\n"
280 "supported audio formats: %s\n"
281 "supported senders: %s\n"
285 mmd
->active_connections
,
289 supported_audio_formats(),
301 int com_version(int fd
, int argc
, __a_unused
char * const * argv
)
304 return -E_COMMAND_SYNTAX
;
305 return send_buffer(fd
, VERSION_TEXT("server")
306 "built: " BUILD_DATE
"\n"
307 SYSTEM
", " CC_VERSION
"\n"
312 int com_stat(int fd
, int argc
, char * const * argv
)
314 int ret
, num
= 0;/* status will be printed that many
315 * times. num <= 0 means: print forever
317 struct misc_meta_data tmp
, *nmmd
= &tmp
;
320 signal(SIGUSR1
, dummy
);
327 s
= get_status(nmmd
);
328 ret
= send_buffer(fd
, s
);
337 return -E_SERVER_CRASH
;
343 static int send_list_of_commands(int fd
, struct server_command
*cmd
,
348 for (i
= 1; cmd
->name
; cmd
++, i
++) {
349 char *perms
= cmd_perms_itohuman(cmd
->perms
);
350 ret
= send_va_buffer(fd
, "%s\t%s\t%s\t%s\n", cmd
->name
,
361 /* returns string that must be freed by the caller */
362 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
364 struct server_command
*cmd
;
366 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
367 if (!strcmp(cmd
->name
, name
)) {
369 *handler
= para_strdup("server"); /* server commands */
372 /* not found, look for commands supported by afs */
373 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
374 if (!strcmp(cmd
->name
, name
)) {
376 *handler
= para_strdup("afs");
383 int com_help(int fd
, int argc
, char * const * argv
)
385 struct server_command
*cmd
;
386 char *perms
, *handler
;
390 /* no argument given, print list of commands */
391 if ((ret
= send_list_of_commands(fd
, server_cmds
, "server")) < 0)
393 return send_list_of_commands(fd
, afs_cmds
, "afs");
395 /* argument given for help */
396 cmd
= get_cmd_ptr(argv
[1], &handler
);
401 perms
= cmd_perms_itohuman(cmd
->perms
);
402 ret
= send_va_buffer(fd
,
421 int com_hup(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
424 return -E_COMMAND_SYNTAX
;
425 kill(getppid(), SIGHUP
);
430 int com_term(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
433 return -E_COMMAND_SYNTAX
;
434 kill(getppid(), SIGTERM
);
438 int com_play(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
441 return -E_COMMAND_SYNTAX
;
443 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
444 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
451 int com_stop(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
454 return -E_COMMAND_SYNTAX
;
456 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
457 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
458 mmd
->new_vss_status_flags
|= VSS_NEXT
;
464 int com_pause(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
467 return -E_COMMAND_SYNTAX
;
471 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
472 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
478 int com_next(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
481 return -E_COMMAND_SYNTAX
;
484 mmd
->new_vss_status_flags
|= VSS_NEXT
;
490 int com_nomore(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
493 return -E_COMMAND_SYNTAX
;
495 if (vss_playing() || vss_paused())
496 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
502 int com_ff(__a_unused
int fd
, int argc
, char * const * argv
)
505 int ret
, backwards
= 0;
510 return -E_COMMAND_SYNTAX
;
511 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
512 return -E_COMMAND_SYNTAX
;
513 if (ret
> 1 && c
== '-')
514 backwards
= 1; /* jmp backwards */
516 ret
= -E_NO_AUDIO_FILE
;
517 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
519 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
521 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
523 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
526 if (promille
> 1000) {
527 mmd
->new_vss_status_flags
|= VSS_NEXT
;
530 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
531 mmd
->new_vss_status_flags
|= VSS_REPOS
;
532 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
541 int com_jmp(__a_unused
int fd
, int argc
, char * const * argv
)
547 return -E_COMMAND_SYNTAX
;
548 if (sscanf(argv
[1], "%lu", &i
) <= 0)
549 return -E_COMMAND_SYNTAX
;
551 ret
= -E_NO_AUDIO_FILE
;
552 if (!mmd
->afd
.afhi
.chunks_total
)
556 PARA_INFO_LOG("jumping to %lu%%\n", i
);
557 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
558 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
559 mmd
->chunks_sent
, mmd
->offset
);
560 mmd
->new_vss_status_flags
|= VSS_REPOS
;
561 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
570 * check if perms are sufficient to exec a command having perms cmd_perms.
571 * Returns 0 if perms are sufficient, -E_PERM otherwise.
573 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
575 PARA_DEBUG_LOG("%s", "checking permissions\n");
576 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
580 * Parse first string from *cmd and lookup in table of valid commands.
581 * On error, NULL is returned.
583 static struct server_command
*parse_cmd(const char *cmdstr
)
588 sscanf(cmdstr
, "%200s%n", buf
, &n
);
592 return get_cmd_ptr(buf
, NULL
);
595 static void init_rc4_keys(void)
599 for (i
= 0; i
< 2 * RC4_KEY_LEN
; i
++)
600 rc4_buf
[i
] = para_random(256);
601 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
602 (unsigned char) rc4_buf
[0],
603 (unsigned char) rc4_buf
[RC4_KEY_LEN
]);
604 RC4_set_key(&rc4_recv_key
, RC4_KEY_LEN
, rc4_buf
);
605 RC4_set_key(&rc4_send_key
, RC4_KEY_LEN
, rc4_buf
+ RC4_KEY_LEN
);
608 static void rc4_recv(unsigned long len
, const unsigned char *indata
,
609 unsigned char *outdata
, __a_unused
void *private_data
)
611 RC4(&rc4_recv_key
, len
, indata
, outdata
);
614 static void rc4_send(unsigned long len
, const unsigned char *indata
,
615 unsigned char *outdata
, __a_unused
void *private_data
)
617 RC4(&rc4_send_key
, len
, indata
, outdata
);
620 static int read_command(int fd
, char **result
)
624 char *command
= NULL
;
630 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
636 ret
= -E_COMMAND_SYNTAX
;
637 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
639 command
= para_strcat(command
, buf
);
640 p
= strstr(command
, EOC_MSG
);
646 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
657 * perform user authentication and execute a command
659 * \param fd the file descriptor to send output to
660 * \param addr socket address info of peer
662 * \return EXIT_SUCCESS or EXIT_FAILURE
664 * Whenever para_server accepts an incoming tcp connection on
665 * the port it listens on, it forks and the resulting child
666 * calls this function.
668 * An RSA-based challenge/response is used to authenticate
669 * the peer. It that authentication succeeds, a random RC4
670 * session key is generated and sent back to the peer,
671 * encrypted with its RSA public key. From this point on,
672 * all transfers are crypted with this session key.
674 * Next it is checked if the peer supplied a valid server command or a command
675 * for the audio file selector. If yes, and if the user has sufficient
676 * permissions to execute that command, the function calls the corresponding
677 * command handler which does argument checking and further processing.
679 * In order to cope with a DOS attacks, a timeout is set up
680 * which terminates the function if the connection was not
681 * authenticated when the timeout expires.
683 * \sa alarm(2), rc4(3), crypt.c, crypt.h
685 int handle_connect(int fd
, struct sockaddr_in
*addr
)
687 int ret
, argc
, use_rc4
= 0;
689 unsigned char crypt_buf
[MAXLINE
];
691 struct server_command
*cmd
= NULL
;
692 long unsigned challenge_nr
, chall_response
;
694 char *p
, *command
= NULL
;
697 signal(SIGCHLD
, SIG_IGN
);
698 signal(SIGINT
, SIG_DFL
);
699 signal(SIGTERM
, SIG_DFL
);
700 signal(SIGHUP
, SIG_DFL
);
701 signal(SIGUSR1
, SIG_IGN
);
703 challenge_nr
= random();
704 /* send Welcome message */
705 ret
= send_va_buffer(fd
, "This is para_server, version "
706 PACKAGE_VERSION
".\n" );
709 /* recv auth request line */
710 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
719 if (strncmp(buf
, "auth ", 5))
722 if (numbytes
< 9 || strncmp(buf
, "auth rc4 ", 9))
723 p
= buf
+ 5; /* client version < 0.2.6 */
725 p
= buf
+ 9; /* client version >= 0.2.6 */
728 PARA_DEBUG_LOG("received %s request for user %s\n",
729 use_rc4
? "rc4" : "auth", p
);
734 ret
= para_encrypt_challenge(u
->rsa
, challenge_nr
, crypt_buf
);
738 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes
);
739 /* We can't use send_buffer here since buf may contain null bytes */
740 ret
= send_bin_buffer(fd
,(char *) crypt_buf
, numbytes
);
743 /* recv decrypted number */
744 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
751 if (sscanf(buf
, CHALLENGE_RESPONSE_MSG
"%lu", &chall_response
) < 1
752 || chall_response
!= challenge_nr
)
754 /* auth successful, send 'Proceed' message */
755 PARA_INFO_LOG("good auth for %s (%lu)\n", u
->name
, challenge_nr
);
756 sprintf(buf
, "%s", PROCEED_MSG
);
759 ret
= para_encrypt_buffer(u
->rsa
, rc4_buf
, 2 * RC4_KEY_LEN
,
760 (unsigned char *)buf
+ PROCEED_MSG_LEN
+ 1);
763 numbytes
= ret
+ strlen(PROCEED_MSG
) + 1;
765 numbytes
= strlen(buf
);
766 ret
= send_bin_buffer(fd
, buf
, numbytes
);
770 enable_crypt(fd
, rc4_recv
, rc4_send
, NULL
);
771 ret
= read_command(fd
, &command
);
775 cmd
= parse_cmd(command
);
778 /* valid command, check permissions */
779 ret
= check_perms(u
->perms
, cmd
);
782 /* valid command and sufficient perms */
784 argc
= split_args(command
, &argv
, "\n");
788 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
789 inet_ntoa(addr
->sin_addr
));
790 ret
= cmd
->handler(fd
, argc
, argv
);
796 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret
));
797 if (ret
!= -E_SEND
&& ret
!= -E_RECV
)
798 send_va_buffer(fd
, "%s\n", PARA_STRERROR(-ret
));
804 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
806 mmd
->active_connections
--;