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: %lu.%lu\n" /* stream start */
122 "%s: %lu.%lu\n" /* current server time */
123 "%s", /* afs status info */
124 status_item_list
[SI_FILE_SIZE
], nmmd
->size
/ 1024,
125 status_item_list
[SI_MTIME
], mtime
,
126 status_item_list
[SI_STATUS
], status
,
127 status_item_list
[SI_STATUS_FLAGS
], flags
,
129 status_item_list
[SI_OFFSET
], offset
,
130 status_item_list
[SI_AFS_MODE
], mmd
->afs_mode_string
,
132 status_item_list
[SI_STREAM_START
],
133 (long unsigned)nmmd
->stream_start
.tv_sec
,
134 (long unsigned)nmmd
->stream_start
.tv_usec
,
135 status_item_list
[SI_CURRENT_TIME
],
136 (long unsigned)now
.tv_sec
,
137 (long unsigned)now
.tv_usec
,
139 nmmd
->afd
.verbose_ls_output
148 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
151 /* this has to match sender.h */
152 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
154 scd
->sender_num
= -1;
156 return -E_COMMAND_SYNTAX
;
157 for (i
= 0; senders
[i
].name
; i
++)
158 if (!strcmp(senders
[i
].name
, argv
[1]))
160 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
161 if (!senders
[i
].name
)
162 return -E_COMMAND_SYNTAX
;
164 for (i
= 0; subcmds
[i
]; i
++)
165 if (!strcmp(subcmds
[i
], argv
[2]))
168 return -E_COMMAND_SYNTAX
;
171 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
]) {
173 return -E_SENDER_CMD
;
176 switch (scd
->cmd_num
) {
180 return -E_COMMAND_SYNTAX
;
184 if (argc
!= 4 && argc
!= 5)
185 return -E_COMMAND_SYNTAX
;
186 if (!inet_pton(AF_INET
, argv
[3], &scd
->addr
))
187 return -E_COMMAND_SYNTAX
;
190 scd
->netmask
= atoi(argv
[4]);
191 if (scd
->netmask
< 0 || scd
->netmask
> 32)
192 return -E_COMMAND_SYNTAX
;
197 if (argc
!= 4 && argc
!= 5)
198 return -E_COMMAND_SYNTAX
;
199 if (!inet_pton(AF_INET
, argv
[3], &scd
->addr
))
200 return -E_COMMAND_SYNTAX
;
203 scd
->port
= atoi(argv
[4]);
204 if (scd
->port
< 0 || scd
->port
> 65535)
205 return -E_COMMAND_SYNTAX
;
209 return -E_COMMAND_SYNTAX
;
214 int com_sender(int fd
, int argc
, char * const * argv
)
217 struct sender_command_data scd
;
221 for (i
= 0; senders
[i
].name
; i
++) {
222 char *tmp
= make_message("%s%s\n",
223 msg
? msg
: "", senders
[i
].name
);
227 ret
= send_buffer(fd
, msg
);
231 ret
= check_sender_args(argc
, argv
, &scd
);
234 if (scd
.sender_num
< 0)
236 msg
= senders
[scd
.sender_num
].help();
237 send_buffer(fd
, msg
);
241 for (i
= 0; i
< 10; i
++) {
243 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
248 mmd
->sender_cmd_data
= scd
;
252 return (i
< 10)? 1 : -E_LOCK
;
256 int com_si(int fd
, int argc
, __a_unused
char * const * argv
)
260 char *sender_info
= NULL
, *sender_list
= NULL
;
263 return -E_COMMAND_SYNTAX
;
265 for (i
= 0; senders
[i
].name
; i
++) {
266 char *info
= senders
[i
].info();
267 sender_info
= para_strcat(sender_info
, info
);
269 sender_list
= para_strcat(sender_list
, senders
[i
].name
);
270 sender_list
= para_strcat(sender_list
, " ");
273 ret
= send_va_buffer(fd
, "up: %s\nplayed: %u\n"
275 "connections (active/accepted/total): %u/%u/%u\n"
276 "current loglevel: %i\n"
277 "supported audio formats: %s\n"
278 "supported senders: %s\n"
282 mmd
->active_connections
,
286 supported_audio_formats(),
298 int com_version(int fd
, int argc
, __a_unused
char * const * argv
)
301 return -E_COMMAND_SYNTAX
;
302 return send_buffer(fd
, VERSION_TEXT("server")
303 "built: " BUILD_DATE
"\n"
304 SYSTEM
", " CC_VERSION
"\n"
309 int com_stat(int fd
, int argc
, char * const * argv
)
311 int ret
, num
= 0;/* status will be printed that many
312 * times. num <= 0 means: print forever
314 struct misc_meta_data tmp
, *nmmd
= &tmp
;
317 signal(SIGUSR1
, dummy
);
324 s
= get_status(nmmd
);
325 ret
= send_buffer(fd
, s
);
334 return -E_SERVER_CRASH
;
340 static int send_list_of_commands(int fd
, struct server_command
*cmd
,
345 for (i
= 1; cmd
->name
; cmd
++, i
++) {
346 char *perms
= cmd_perms_itohuman(cmd
->perms
);
347 ret
= send_va_buffer(fd
, "%s\t%s\t%s\t%s\n", cmd
->name
,
358 /* returns string that must be freed by the caller */
359 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
361 struct server_command
*cmd
;
363 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
364 if (!strcmp(cmd
->name
, name
)) {
366 *handler
= para_strdup("server"); /* server commands */
369 /* not found, look for commands supported by afs */
370 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
371 if (!strcmp(cmd
->name
, name
)) {
373 *handler
= para_strdup("afs");
380 int com_help(int fd
, int argc
, char * const * argv
)
382 struct server_command
*cmd
;
383 char *perms
, *handler
;
387 /* no argument given, print list of commands */
388 if ((ret
= send_list_of_commands(fd
, server_cmds
, "server")) < 0)
390 return send_list_of_commands(fd
, afs_cmds
, "afs");
392 /* argument given for help */
393 cmd
= get_cmd_ptr(argv
[1], &handler
);
398 perms
= cmd_perms_itohuman(cmd
->perms
);
399 ret
= send_va_buffer(fd
,
418 int com_hup(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
421 return -E_COMMAND_SYNTAX
;
422 kill(getppid(), SIGHUP
);
427 int com_term(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
430 return -E_COMMAND_SYNTAX
;
431 kill(getppid(), SIGTERM
);
435 int com_play(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
438 return -E_COMMAND_SYNTAX
;
440 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
441 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
448 int com_stop(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
451 return -E_COMMAND_SYNTAX
;
453 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
454 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
455 mmd
->new_vss_status_flags
|= VSS_NEXT
;
461 int com_pause(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
464 return -E_COMMAND_SYNTAX
;
466 if (!vss_paused() && !vss_stopped()) {
468 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
469 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
476 int com_next(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
479 return -E_COMMAND_SYNTAX
;
482 mmd
->new_vss_status_flags
|= VSS_NEXT
;
488 int com_nomore(__a_unused
int fd
, int argc
, __a_unused
char * const * argv
)
491 return -E_COMMAND_SYNTAX
;
493 if (vss_playing() || vss_paused())
494 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
500 int com_ff(__a_unused
int fd
, int argc
, char * const * argv
)
503 int ret
, backwards
= 0;
508 return -E_COMMAND_SYNTAX
;
509 if (!(ret
= sscanf(argv
[1], "%u%c", &i
, &c
)))
510 return -E_COMMAND_SYNTAX
;
511 if (ret
> 1 && c
== '-')
512 backwards
= 1; /* jmp backwards */
514 ret
= -E_NO_AUDIO_FILE
;
515 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
517 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
519 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
521 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
524 if (promille
> 1000) {
525 mmd
->new_vss_status_flags
|= VSS_NEXT
;
528 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
529 mmd
->new_vss_status_flags
|= VSS_REPOS
;
530 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
539 int com_jmp(__a_unused
int fd
, int argc
, char * const * argv
)
545 return -E_COMMAND_SYNTAX
;
546 if (sscanf(argv
[1], "%lu", &i
) <= 0)
547 return -E_COMMAND_SYNTAX
;
549 ret
= -E_NO_AUDIO_FILE
;
550 if (!mmd
->afd
.afhi
.chunks_total
)
554 PARA_INFO_LOG("jumping to %lu%%\n", i
);
555 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
556 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
557 mmd
->chunks_sent
, mmd
->offset
);
558 mmd
->new_vss_status_flags
|= VSS_REPOS
;
559 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
568 * check if perms are sufficient to exec a command having perms cmd_perms.
569 * Returns 0 if perms are sufficient, -E_PERM otherwise.
571 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
573 PARA_DEBUG_LOG("%s", "checking permissions\n");
574 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
578 * Parse first string from *cmd and lookup in table of valid commands.
579 * On error, NULL is returned.
581 static struct server_command
*parse_cmd(const char *cmdstr
)
586 sscanf(cmdstr
, "%200s%n", buf
, &n
);
590 return get_cmd_ptr(buf
, NULL
);
593 static void init_rc4_keys(void)
597 for (i
= 0; i
< 2 * RC4_KEY_LEN
; i
++)
598 rc4_buf
[i
] = para_random(256);
599 PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
600 (unsigned char) rc4_buf
[0],
601 (unsigned char) rc4_buf
[RC4_KEY_LEN
]);
602 RC4_set_key(&rc4_recv_key
, RC4_KEY_LEN
, rc4_buf
);
603 RC4_set_key(&rc4_send_key
, RC4_KEY_LEN
, rc4_buf
+ RC4_KEY_LEN
);
606 static void rc4_recv(unsigned long len
, const unsigned char *indata
,
607 unsigned char *outdata
, __a_unused
void *private_data
)
609 RC4(&rc4_recv_key
, len
, indata
, outdata
);
612 static void rc4_send(unsigned long len
, const unsigned char *indata
,
613 unsigned char *outdata
, __a_unused
void *private_data
)
615 RC4(&rc4_send_key
, len
, indata
, outdata
);
618 static int read_command(int fd
, char **result
)
622 char *command
= NULL
;
628 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
634 ret
= -E_COMMAND_SYNTAX
;
635 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
637 command
= para_strcat(command
, buf
);
638 p
= strstr(command
, EOC_MSG
);
644 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
655 * perform user authentication and execute a command
657 * \param fd The file descriptor to send output to
658 * \param peername Identifies the connecting peer.
660 * \return EXIT_SUCCESS or EXIT_FAILURE
662 * Whenever para_server accepts an incoming tcp connection on
663 * the port it listens on, it forks and the resulting child
664 * calls this function.
666 * An RSA-based challenge/response is used to authenticate
667 * the peer. It that authentication succeeds, a random RC4
668 * session key is generated and sent back to the peer,
669 * encrypted with its RSA public key. From this point on,
670 * all transfers are crypted with this session key.
672 * Next it is checked if the peer supplied a valid server command or a command
673 * for the audio file selector. If yes, and if the user has sufficient
674 * permissions to execute that command, the function calls the corresponding
675 * command handler which does argument checking and further processing.
677 * In order to cope with a DOS attacks, a timeout is set up
678 * which terminates the function if the connection was not
679 * authenticated when the timeout expires.
681 * \sa alarm(2), rc4(3), crypt.c, crypt.h
683 int handle_connect(int fd
, const char *peername
)
685 int ret
, argc
, use_rc4
= 0;
687 unsigned char crypt_buf
[MAXLINE
];
689 struct server_command
*cmd
= NULL
;
690 long unsigned challenge_nr
, chall_response
;
692 char *p
, *command
= NULL
;
695 signal(SIGCHLD
, SIG_IGN
);
696 signal(SIGINT
, SIG_DFL
);
697 signal(SIGTERM
, SIG_DFL
);
698 signal(SIGHUP
, SIG_DFL
);
699 signal(SIGUSR1
, SIG_IGN
);
701 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
702 ret
= mark_fd_blocking(fd
);
705 challenge_nr
= random();
706 /* send Welcome message */
707 ret
= send_va_buffer(fd
, "This is para_server, version "
708 PACKAGE_VERSION
".\n" );
711 /* recv auth request line */
712 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
721 if (strncmp(buf
, "auth ", 5))
724 if (numbytes
< 9 || strncmp(buf
, "auth rc4 ", 9))
725 p
= buf
+ 5; /* client version < 0.2.6 */
727 p
= buf
+ 9; /* client version >= 0.2.6 */
730 PARA_DEBUG_LOG("received %s request for user %s\n",
731 use_rc4
? "rc4" : "auth", p
);
736 ret
= para_encrypt_challenge(u
->rsa
, challenge_nr
, crypt_buf
);
740 PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes
);
741 /* We can't use send_buffer here since buf may contain null bytes */
742 ret
= send_bin_buffer(fd
,(char *) crypt_buf
, numbytes
);
745 /* recv decrypted number */
746 ret
= recv_buffer(fd
, buf
, sizeof(buf
));
753 if (sscanf(buf
, CHALLENGE_RESPONSE_MSG
"%lu", &chall_response
) < 1
754 || chall_response
!= challenge_nr
)
756 /* auth successful, send 'Proceed' message */
757 PARA_INFO_LOG("good auth for %s (%lu)\n", u
->name
, challenge_nr
);
758 sprintf(buf
, "%s", PROCEED_MSG
);
761 ret
= para_encrypt_buffer(u
->rsa
, rc4_buf
, 2 * RC4_KEY_LEN
,
762 (unsigned char *)buf
+ PROCEED_MSG_LEN
+ 1);
765 numbytes
= ret
+ strlen(PROCEED_MSG
) + 1;
767 numbytes
= strlen(buf
);
768 ret
= send_bin_buffer(fd
, buf
, numbytes
);
772 enable_crypt(fd
, rc4_recv
, rc4_send
, NULL
);
773 ret
= read_command(fd
, &command
);
774 if (ret
== -E_COMMAND_SYNTAX
)
779 cmd
= parse_cmd(command
);
782 /* valid command, check permissions */
783 ret
= check_perms(u
->perms
, cmd
);
786 /* valid command and sufficient perms */
788 argc
= split_args(command
, &argv
, "\n");
792 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
, u
->name
,
794 ret
= cmd
->handler(fd
, argc
, argv
);
800 send_va_buffer(fd
, "%s\n", PARA_STRERROR(-ret
));
802 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret
));
808 if (cmd
&& (cmd
->perms
& AFS_WRITE
) && ret
>= 0)
810 mmd
->active_connections
--;