2 * Copyright (C) 1997-2012 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"
33 #include "user_list.h"
34 #include "server_command_list.h"
35 #include "afs_command_list.h"
39 struct server_command afs_cmds
[] = {DEFINE_AFS_CMD_ARRAY
};
40 struct server_command server_cmds
[] = {DEFINE_SERVER_CMD_ARRAY
};
42 /** Commands including options must be shorter than this. */
43 #define MAX_COMMAND_LEN 32768
46 extern struct misc_meta_data
*mmd
;
47 extern struct sender senders
[];
48 int send_afs_status(struct command_context
*cc
, int parser_friendly
);
50 static void dummy(__a_unused
int s
)
54 static void mmd_dup(struct misc_meta_data
*new_mmd
)
56 mutex_lock(mmd_mutex
);
58 mutex_unlock(mmd_mutex
);
62 * Compute human readable string containing vss status for given integer value.
64 * We don't want to use vss_playing() and friends here because we take a
65 * snapshot of the mmd struct and use the copy for computing the state of the
66 * vss. If the real data were used, we would take the mmd lock for a rather
67 * long time or risk to get an inconsistent view.
69 static char *vss_status_tohuman(unsigned int flags
)
71 if (flags
& VSS_PLAYING
)
72 return para_strdup("playing");
74 return para_strdup("stopped");
75 return para_strdup("paused");
79 * return human readable permission string. Never returns NULL.
81 static char *cmd_perms_itohuman(unsigned int perms
)
83 char *msg
= para_malloc(5 * sizeof(char));
85 msg
[0] = perms
& AFS_READ
? 'a' : '-';
86 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
87 msg
[2] = perms
& VSS_READ
? 'v' : '-';
88 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
96 static char *vss_get_status_flags(unsigned int flags
)
98 char *msg
= para_malloc(5 * sizeof(char));
100 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
101 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
102 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
103 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
108 static unsigned get_status(struct misc_meta_data
*nmmd
, int parser_friendly
,
112 char *status
, *flags
; /* vss status info */
113 /* nobody updates our version of "now" */
114 char *ut
= get_server_uptime_str(NULL
);
115 long offset
= (nmmd
->offset
+ 500) / 1000;
116 struct timeval current_time
;
118 struct para_buffer b
= {.flags
= parser_friendly
? PBF_SIZE_PREFIX
: 0};
120 /* report real status */
121 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
122 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
123 if (nmmd
->size
) { /* parent currently has an audio file open */
124 localtime_r(&nmmd
->mtime
, &mtime_tm
);
125 strftime(mtime
, 29, "%b %d %Y", &mtime_tm
);
127 gettimeofday(¤t_time
, NULL
);
129 * The calls to WRITE_STATUS_ITEM() below never fail because
130 * b->max_size is zero (unlimited), see para_printf(). However, clang
131 * is not smart enough to prove this and complains nevertheless.
132 * Casting the return value to void silences clang.
134 (void)WRITE_STATUS_ITEM(&b
, SI_FILE_SIZE
, "%zu\n", nmmd
->size
/ 1024);
135 (void)WRITE_STATUS_ITEM(&b
, SI_MTIME
, "%s\n", mtime
);
136 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
137 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
138 (void)WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
139 (void)WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
140 (void)WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
141 (long unsigned)nmmd
->stream_start
.tv_sec
,
142 (long unsigned)nmmd
->stream_start
.tv_usec
);
143 (void)WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
144 (long unsigned)current_time
.tv_sec
,
145 (long unsigned)current_time
.tv_usec
);
153 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
156 /* this has to match sender.h */
157 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
159 scd
->sender_num
= -1;
161 return -E_COMMAND_SYNTAX
;
162 for (i
= 0; senders
[i
].name
; i
++)
163 if (!strcmp(senders
[i
].name
, argv
[1]))
165 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
166 if (!senders
[i
].name
)
167 return -E_COMMAND_SYNTAX
;
169 for (i
= 0; subcmds
[i
]; i
++)
170 if (!strcmp(subcmds
[i
], argv
[2]))
173 return -E_COMMAND_SYNTAX
;
175 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
176 return -E_SENDER_CMD
;
177 switch (scd
->cmd_num
) {
181 return -E_COMMAND_SYNTAX
;
185 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
186 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
187 return -E_COMMAND_SYNTAX
;
192 return -E_COMMAND_SYNTAX
;
193 return parse_fec_url(argv
[3], scd
);
195 return -E_COMMAND_SYNTAX
;
201 * Send a sideband packet through a blocking file descriptor.
203 * \param scc fd and crypto keys.
204 * \param buf The buffer to send.
205 * \param numbytes The size of \a buf.
206 * \param band The sideband designator of this packet.
207 * \param dont_free If true, never deallocate \a buf.
209 * The nonblock flag must be disabled for the file descriptor given by \a scc.
211 * Stream cipher encryption is automatically activated if neccessary via the
212 * sideband transformation, depending on the value of \a band.
216 * \sa \ref send_sb_va().
218 int send_sb(struct stream_cipher_context
*scc
, void *buf
, size_t numbytes
,
219 int band
, bool dont_free
)
222 struct sb_context
*sbc
;
224 struct sb_buffer sbb
= SBB_INIT(band
, buf
, numbytes
);
225 sb_transformation trafo
= band
< SBD_PROCEED
? NULL
: sc_trafo
;
227 sbc
= sb_new_send(&sbb
, dont_free
, trafo
, scc
->send
);
229 ret
= sb_get_send_buffers(sbc
, iov
);
230 ret
= xwritev(scc
->fd
, iov
, ret
);
233 } while (sb_sent(sbc
, ret
) == false);
241 * Create a variable sized buffer and send it as a sideband packet.
243 * \param scc Passed to \ref send_sb.
244 * \param band See \ref send_sb.
245 * \param fmt The format string.
247 * \return The return value of the underlying call to \ref send_sb.
249 __printf_3_4
int send_sb_va(struct stream_cipher_context
*scc
, int band
,
250 const char *fmt
, ...)
257 ret
= xvasprintf(&msg
, fmt
, ap
);
259 return send_sb(scc
, msg
, ret
, band
, false);
262 int send_strerror(struct command_context
*cc
, int err
)
264 return cc
->use_sideband
?
265 send_sb_va(&cc
->scc
, SBD_ERROR_LOG
, "%s\n", para_strerror(err
))
267 sc_send_va_buffer(&cc
->scc
, "%s\n", para_strerror(err
));
271 * Send a sideband packet through a blocking file descriptor.
273 * \param scc fd and crypto keys.
274 * \param expected_band The expected band designator.
275 * \param max_size Passed to \ref sb_new_recv().
276 * \param result Body of the sideband packet is returned here.
278 * If \a expected_band is not \p SBD_ANY, the band designator of the received
279 * sideband packet is compared to \a expected_band and a mismatch is considered
284 int recv_sb(struct stream_cipher_context
*scc
,
285 enum sb_designator expected_band
,
286 size_t max_size
, struct iovec
*result
)
289 struct sb_context
*sbc
;
291 struct sb_buffer sbb
;
292 sb_transformation trafo
;
294 trafo
= expected_band
!= SBD_ANY
&& expected_band
< SBD_PROCEED
?
296 sbc
= sb_new_recv(max_size
, trafo
, scc
->recv
);
298 sb_get_recv_buffer(sbc
, &iov
);
299 ret
= recv_bin_buffer(scc
->fd
, iov
.iov_base
, iov
.iov_len
);
304 ret
= sb_received(sbc
, ret
, &sbb
);
311 if (expected_band
!= SBD_ANY
&& sbb
.band
!= expected_band
)
320 int com_sender(struct command_context
*cc
)
324 struct sender_command_data scd
;
327 for (i
= 0; senders
[i
].name
; i
++) {
329 ret
= xasprintf(&tmp
, "%s%s\n", msg
? msg
: "",
334 if (cc
->use_sideband
)
335 return send_sb(&cc
->scc
, msg
, ret
, SBD_OUTPUT
, false);
336 ret
= sc_send_buffer(&cc
->scc
, msg
);
340 ret
= check_sender_args(cc
->argc
, cc
->argv
, &scd
);
342 if (scd
.sender_num
< 0)
344 msg
= senders
[scd
.sender_num
].help();
345 if (cc
->use_sideband
)
346 return send_sb(&cc
->scc
, msg
, strlen(msg
), SBD_OUTPUT
,
348 ret
= sc_send_buffer(&cc
->scc
, msg
);
353 switch (scd
.cmd_num
) {
356 assert(senders
[scd
.sender_num
].resolve_target
);
357 ret
= senders
[scd
.sender_num
].resolve_target(cc
->argv
[3], &scd
);
362 for (i
= 0; i
< 10; i
++) {
363 mutex_lock(mmd_mutex
);
364 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
365 mutex_unlock(mmd_mutex
);
369 memcpy(&mmd
->sender_cmd_data
, &scd
, sizeof(scd
));
370 mutex_unlock(mmd_mutex
);
373 return (i
< 10)? 1 : -E_LOCK
;
377 int com_si(struct command_context
*cc
)
380 char *msg
, *ut
, *sender_info
= NULL
;
383 return -E_COMMAND_SYNTAX
;
384 mutex_lock(mmd_mutex
);
385 for (i
= 0; senders
[i
].name
; i
++) {
386 char *info
= senders
[i
].info();
387 sender_info
= para_strcat(sender_info
, info
);
390 ut
= get_server_uptime_str(now
);
391 ret
= xasprintf(&msg
, "version: " GIT_VERSION
"\n"
392 "up: %s\nplayed: %u\n"
395 "connections (active/accepted/total): %u/%u/%u\n"
396 "current loglevel: %s\n"
397 "supported audio formats: %s\n"
402 mmd
->active_connections
,
406 SERVER_AUDIO_FORMATS
,
409 mutex_unlock(mmd_mutex
);
412 if (cc
->use_sideband
)
413 return send_sb(&cc
->scc
, msg
, ret
, SBD_OUTPUT
, false);
414 ret
= sc_send_bin_buffer(&cc
->scc
, msg
, ret
);
420 int com_version(struct command_context
*cc
)
426 return -E_COMMAND_SYNTAX
;
427 msg
= VERSION_TEXT("server") "built: " BUILD_DATE
"\n" UNAME_RS
428 ", " CC_VERSION
"\n";
430 if (cc
->use_sideband
)
431 return send_sb(&cc
->scc
, msg
, len
, SBD_OUTPUT
, true);
432 return sc_send_bin_buffer(&cc
->scc
, msg
, len
);
435 #define EMPTY_STATUS_ITEMS \
440 ITEM(ATTRIBUTES_BITMAP) \
441 ITEM(ATTRIBUTES_TXT) \
452 ITEM(SECONDS_TOTAL) \
464 * Write a list of audio-file related status items with empty values.
466 * This is used by vss when currently no audio file is open.
468 static unsigned empty_status_items(int parser_friendly
, char **result
)
477 len
= xasprintf(&esi
,
478 #define ITEM(x) "0004 %02x:\n"
481 #define ITEM(x) , SI_ ## x
486 len
= xasprintf(&esi
,
487 #define ITEM(x) "%s:\n"
490 #define ITEM(x) ,status_item_list[SI_ ## x]
498 #undef EMPTY_STATUS_ITEMS
501 int com_stat(struct command_context
*cc
)
504 struct misc_meta_data tmp
, *nmmd
= &tmp
;
505 char *s
, *esi
= NULL
;
507 int parser_friendly
= 0;
509 para_sigaction(SIGUSR1
, dummy
);
511 for (i
= 1; i
< cc
->argc
; i
++) {
512 const char *arg
= cc
->argv
[i
];
515 if (!strcmp(arg
, "--")) {
519 if (!strncmp(arg
, "-n=", 3)) {
520 ret
= para_atoi32(arg
+ 3, &num
);
525 if (!strcmp(arg
, "-p")) {
529 return -E_COMMAND_SYNTAX
;
532 return -E_COMMAND_SYNTAX
;
535 ret
= get_status(nmmd
, parser_friendly
, &s
);
536 if (cc
->use_sideband
)
537 ret
= send_sb(&cc
->scc
, s
, ret
, SBD_OUTPUT
, false);
539 ret
= sc_send_bin_buffer(&cc
->scc
, s
, ret
);
544 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
545 ret
= empty_status_items(parser_friendly
, &esi
);
546 if (cc
->use_sideband
)
547 ret
= send_sb(&cc
->scc
, esi
, ret
, SBD_OUTPUT
,
550 ret
= sc_send_bin_buffer(&cc
->scc
, esi
, ret
);
554 send_afs_status(cc
, parser_friendly
);
556 if (num
> 0 && !--num
)
559 ret
= -E_SERVER_CRASH
;
568 static int send_list_of_commands(struct command_context
*cc
, struct server_command
*cmd
,
574 for (; cmd
->name
; cmd
++) {
575 char *tmp
, *perms
= cmd_perms_itohuman(cmd
->perms
);
576 tmp
= make_message("%s\t%s\t%s\t%s\n", cmd
->name
, handler
,
577 perms
, cmd
->description
);
579 msg
= para_strcat(msg
, tmp
);
582 if (cc
->use_sideband
)
583 return send_sb(&cc
->scc
, msg
, strlen(msg
), SBD_OUTPUT
, false);
584 ret
= sc_send_buffer(&cc
->scc
, msg
);
589 /* returns string that must be freed by the caller */
590 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
592 struct server_command
*cmd
;
594 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
595 if (!strcmp(cmd
->name
, name
)) {
597 *handler
= para_strdup("server"); /* server commands */
600 /* not found, look for commands supported by afs */
601 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
602 if (!strcmp(cmd
->name
, name
)) {
604 *handler
= para_strdup("afs");
611 int com_help(struct command_context
*cc
)
613 struct server_command
*cmd
;
614 char *perms
, *handler
, *buf
;
618 /* no argument given, print list of commands */
619 if ((ret
= send_list_of_commands(cc
, server_cmds
, "server")) < 0)
621 return send_list_of_commands(cc
, afs_cmds
, "afs");
623 /* argument given for help */
624 cmd
= get_cmd_ptr(cc
->argv
[1], &handler
);
627 perms
= cmd_perms_itohuman(cmd
->perms
);
628 ret
= xasprintf(&buf
, "%s - %s\n\n"
642 if (cc
->use_sideband
)
643 return send_sb(&cc
->scc
, buf
, ret
, SBD_OUTPUT
, false);
644 ret
= sc_send_buffer(&cc
->scc
, buf
);
650 int com_hup(struct command_context
*cc
)
653 return -E_COMMAND_SYNTAX
;
654 kill(getppid(), SIGHUP
);
659 int com_term(struct command_context
*cc
)
662 return -E_COMMAND_SYNTAX
;
663 kill(getppid(), SIGTERM
);
667 int com_play(struct command_context
*cc
)
670 return -E_COMMAND_SYNTAX
;
671 mutex_lock(mmd_mutex
);
672 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
673 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
674 mutex_unlock(mmd_mutex
);
679 int com_stop(struct command_context
*cc
)
682 return -E_COMMAND_SYNTAX
;
683 mutex_lock(mmd_mutex
);
684 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
685 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
686 mmd
->new_vss_status_flags
|= VSS_NEXT
;
687 mutex_unlock(mmd_mutex
);
692 int com_pause(struct command_context
*cc
)
695 return -E_COMMAND_SYNTAX
;
696 mutex_lock(mmd_mutex
);
697 if (!vss_paused() && !vss_stopped()) {
699 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
700 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
702 mutex_unlock(mmd_mutex
);
707 int com_next(struct command_context
*cc
)
710 return -E_COMMAND_SYNTAX
;
711 mutex_lock(mmd_mutex
);
713 mmd
->new_vss_status_flags
|= VSS_NEXT
;
714 mutex_unlock(mmd_mutex
);
719 int com_nomore(struct command_context
*cc
)
722 return -E_COMMAND_SYNTAX
;
723 mutex_lock(mmd_mutex
);
724 if (vss_playing() || vss_paused())
725 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
726 mutex_unlock(mmd_mutex
);
731 int com_ff(struct command_context
*cc
)
734 int ret
, backwards
= 0;
739 return -E_COMMAND_SYNTAX
;
740 if (!(ret
= sscanf(cc
->argv
[1], "%u%c", &i
, &c
)))
741 return -E_COMMAND_SYNTAX
;
742 if (ret
> 1 && c
== '-')
743 backwards
= 1; /* jmp backwards */
744 mutex_lock(mmd_mutex
);
745 ret
= -E_NO_AUDIO_FILE
;
746 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
748 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
750 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
752 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
755 if (promille
> 1000) {
756 mmd
->new_vss_status_flags
|= VSS_NEXT
;
759 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
760 mmd
->new_vss_status_flags
|= VSS_REPOS
;
761 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
765 mutex_unlock(mmd_mutex
);
770 int com_jmp(struct command_context
*cc
)
776 return -E_COMMAND_SYNTAX
;
777 if (sscanf(cc
->argv
[1], "%lu", &i
) <= 0)
778 return -E_COMMAND_SYNTAX
;
779 mutex_lock(mmd_mutex
);
780 ret
= -E_NO_AUDIO_FILE
;
781 if (!mmd
->afd
.afhi
.chunks_total
)
785 PARA_INFO_LOG("jumping to %lu%%\n", i
);
786 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50)/ 100;
787 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
788 mmd
->chunks_sent
, mmd
->offset
);
789 mmd
->new_vss_status_flags
|= VSS_REPOS
;
790 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
794 mutex_unlock(mmd_mutex
);
799 * check if perms are sufficient to exec a command having perms cmd_perms.
800 * Returns 0 if perms are sufficient, -E_PERM otherwise.
802 static int check_perms(unsigned int perms
, struct server_command
*cmd_ptr
)
804 PARA_DEBUG_LOG("checking permissions\n");
805 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
809 * Parse first string from *cmd and lookup in table of valid commands.
810 * On error, NULL is returned.
812 static struct server_command
*parse_cmd(const char *cmdstr
)
817 sscanf(cmdstr
, "%200s%n", buf
, &n
);
821 return get_cmd_ptr(buf
, NULL
);
824 static int read_command(struct stream_cipher_context
*scc
, char **result
)
828 char *command
= NULL
;
834 ret
= sc_recv_buffer(scc
, buf
, sizeof(buf
));
840 ret
= -E_COMMAND_SYNTAX
;
841 if (command
&& numbytes
+ strlen(command
) > MAX_COMMAND_LEN
) /* DOS */
843 command
= para_strcat(command
, buf
);
844 p
= strstr(command
, EOC_MSG
);
850 ret
= command
? 1 : -E_COMMAND_SYNTAX
;
860 static void reset_signals(void)
862 para_sigaction(SIGCHLD
, SIG_IGN
);
863 para_sigaction(SIGINT
, SIG_DFL
);
864 para_sigaction(SIGTERM
, SIG_DFL
);
865 para_sigaction(SIGHUP
, SIG_DFL
);
868 static int parse_auth_request(char *buf
, int len
, struct user
**u
,
872 char *p
, *username
, **features
= NULL
;
873 size_t auth_rq_len
= strlen(AUTH_REQUEST_MSG
);
876 *use_sideband
= false;
877 if (len
< auth_rq_len
+ 2)
878 return -E_AUTH_REQUEST
;
879 if (strncmp(buf
, AUTH_REQUEST_MSG
, auth_rq_len
) != 0)
880 return -E_AUTH_REQUEST
;
881 username
= buf
+ auth_rq_len
;
882 p
= strchr(username
, ' ');
886 return -E_AUTH_REQUEST
;
889 create_argv(p
, ",", &features
);
890 for (i
= 0; features
[i
]; i
++) {
891 if (strcmp(features
[i
], "sideband") == 0)
892 *use_sideband
= true;
894 ret
= -E_BAD_FEATURE
;
899 PARA_DEBUG_LOG("received auth request for user %s (sideband = %s)\n",
900 username
, *use_sideband
? "true" : "false");
901 *u
= lookup_user(username
);
908 #define HANDSHAKE_BUFSIZE 4096
910 static int parse_sb_command(struct command_context
*cc
, struct iovec
*iov
)
916 if (iov
->iov_base
== NULL
|| iov
->iov_len
== 0)
919 p
[iov
->iov_len
- 1] = '\0'; /* just to be sure */
920 cc
->cmd
= get_cmd_ptr(p
, NULL
);
923 ret
= check_perms(cc
->u
->perms
, cc
->cmd
);
926 end
= iov
->iov_base
+ iov
->iov_len
;
927 for (i
= 0, p
= iov
->iov_base
; p
< end
; i
++)
930 cc
->argv
= para_malloc((cc
->argc
+ 1) * sizeof(char *));
931 for (i
= 0, p
= iov
->iov_base
; p
< end
; i
++) {
932 cc
->argv
[i
] = para_strdup(p
);
935 cc
->argv
[cc
->argc
] = NULL
;
943 * Perform user authentication and execute a command.
945 * \param fd The file descriptor to send output to.
946 * \param peername Identifies the connecting peer.
948 * Whenever para_server accepts an incoming tcp connection on
949 * the port it listens on, it forks and the resulting child
950 * calls this function.
952 * An RSA-based challenge/response is used to authenticate
953 * the peer. It that authentication succeeds, a random
954 * session key is generated and sent back to the peer,
955 * encrypted with its RSA public key. From this point on,
956 * all transfers are crypted with this session key.
958 * Next it is checked if the peer supplied a valid server command or a command
959 * for the audio file selector. If yes, and if the user has sufficient
960 * permissions to execute that command, the function calls the corresponding
961 * command handler which does argument checking and further processing.
963 * In order to cope with a DOS attacks, a timeout is set up
964 * which terminates the function if the connection was not
965 * authenticated when the timeout expires.
967 * \sa alarm(2), crypt.c, crypt.h
969 __noreturn
void handle_connect(int fd
, const char *peername
)
972 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * SESSION_KEY_LEN
];
973 unsigned char challenge_hash
[HASH_SIZE
];
974 char *p
, *command
= NULL
, *buf
= para_malloc(HANDSHAKE_BUFSIZE
) /* must be on the heap */;
976 struct command_context cc_struct
= {.peer
= peername
}, *cc
= &cc_struct
;
980 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
981 ret
= mark_fd_blocking(fd
);
984 /* send Welcome message */
985 ret
= write_va_buffer(fd
, "This is para_server, version "
986 PACKAGE_VERSION
".\n"
987 "Features: sideband,foo\n"
991 /* recv auth request line */
992 ret
= recv_buffer(fd
, buf
, HANDSHAKE_BUFSIZE
);
995 ret
= parse_auth_request(buf
, ret
, &cc
->u
, &cc
->use_sideband
);
998 p
= buf
+ strlen(AUTH_REQUEST_MSG
);
999 PARA_DEBUG_LOG("received auth request for user %s\n", p
);
1000 cc
->u
= lookup_user(p
);
1002 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
1003 ret
= pub_encrypt(cc
->u
->pubkey
, rand_buf
, sizeof(rand_buf
),
1004 (unsigned char *)buf
);
1010 * We don't want to reveal our user names, so we send a
1011 * challenge to the client even if the user does not exist, and
1012 * fail the authentication later.
1015 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
1017 PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
1018 CHALLENGE_SIZE
, numbytes
);
1019 if (cc
->use_sideband
) {
1021 ret
= send_sb(&cc
->scc
, buf
, numbytes
, SBD_CHALLENGE
, false);
1025 ret
= recv_sb(&cc
->scc
, SBD_CHALLENGE_RESPONSE
,
1026 HANDSHAKE_BUFSIZE
, &iov
);
1030 numbytes
= iov
.iov_len
;
1032 ret
= write_all(fd
, buf
, numbytes
);
1035 /* recv challenge response */
1036 ret
= recv_bin_buffer(fd
, buf
, HASH_SIZE
);
1041 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes
);
1046 * The correct response is the hash of the first CHALLENGE_SIZE bytes
1047 * of the random data.
1050 if (numbytes
!= HASH_SIZE
)
1052 hash_function((char *)rand_buf
, CHALLENGE_SIZE
, challenge_hash
);
1053 if (memcmp(challenge_hash
, buf
, HASH_SIZE
))
1055 /* auth successful */
1057 PARA_INFO_LOG("good auth for %s\n", cc
->u
->name
);
1058 /* init stream cipher keys with the second part of the random buffer */
1059 cc
->scc
.recv
= sc_new(rand_buf
+ CHALLENGE_SIZE
, SESSION_KEY_LEN
);
1060 cc
->scc
.send
= sc_new(rand_buf
+ CHALLENGE_SIZE
+ SESSION_KEY_LEN
, SESSION_KEY_LEN
);
1061 if (cc
->use_sideband
)
1062 ret
= send_sb(&cc
->scc
, NULL
, 0, SBD_PROCEED
, false);
1064 ret
= sc_send_buffer(&cc
->scc
, PROCEED_MSG
);
1067 if (cc
->use_sideband
) {
1069 ret
= recv_sb(&cc
->scc
, SBD_COMMAND
, MAX_COMMAND_LEN
, &iov
);
1072 ret
= parse_sb_command(cc
, &iov
);
1077 ret
= read_command(&cc
->scc
, &command
);
1078 if (ret
== -E_COMMAND_SYNTAX
)
1083 cc
->cmd
= parse_cmd(command
);
1086 /* valid command, check permissions */
1087 ret
= check_perms(cc
->u
->perms
, cc
->cmd
);
1090 /* valid command and sufficient perms */
1091 ret
= create_argv(command
, "\n", &cc
->argv
);
1096 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cc
->cmd
->name
,
1097 cc
->u
->name
, peername
);
1098 ret
= cc
->cmd
->handler(cc
);
1099 free_argv(cc
->argv
);
1100 mutex_lock(mmd_mutex
);
1101 mmd
->num_commands
++;
1102 mutex_unlock(mmd_mutex
);
1106 if (send_strerror(cc
, -ret
) >= 0 && cc
->use_sideband
)
1107 send_sb(&cc
->scc
, NULL
, 0, SBD_EXIT__FAILURE
, true);
1109 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
1113 mutex_lock(mmd_mutex
);
1114 if (cc
->cmd
&& (cc
->cmd
->perms
& AFS_WRITE
) && ret
>= 0)
1116 mmd
->active_connections
--;
1117 mutex_unlock(mmd_mutex
);
1118 if (ret
>= 0 && cc
->use_sideband
) {
1119 ret
= send_sb(&cc
->scc
, NULL
, 0, SBD_EXIT__SUCCESS
, true);
1121 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
1123 sc_free(cc
->scc
.recv
);
1124 sc_free(cc
->scc
.send
);
1125 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);