2 * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file command.c Client authentication and server commands. */
9 #include <netinet/in.h>
10 #include <sys/socket.h>
13 #include <sys/types.h>
15 #include <arpa/inet.h>
24 #include "server.cmdline.h"
37 #include "user_list.h"
38 #include "server.command_list.h"
39 #include "afs.command_list.h"
43 typedef int server_command_handler_t(struct command_context
*);
44 static server_command_handler_t SERVER_COMMAND_HANDLERS
;
45 server_command_handler_t AFS_COMMAND_HANDLERS
;
47 /* Defines one command of para_server. */
48 struct server_command
{
49 /* The name of the command. */
51 /* Pointer to the function that handles the command. */
52 server_command_handler_t
*handler
;
53 /* The privileges a user must have to execute this command. */
55 /* One-line description of the command. */
56 const char *description
;
57 /* Summary of the command line options. */
59 /* The long help text. */
63 static struct server_command afs_cmds
[] = {DEFINE_AFS_CMD_ARRAY
};
64 static struct server_command server_cmds
[] = {DEFINE_SERVER_CMD_ARRAY
};
66 /** Commands including options must be shorter than this. */
67 #define MAX_COMMAND_LEN 32768
70 extern struct misc_meta_data
*mmd
;
71 extern struct sender senders
[];
72 int send_afs_status(struct command_context
*cc
, int parser_friendly
);
74 static void dummy(__a_unused
int s
)
79 * Compute human readable vss status text.
81 * We can't call vss_playing() and friends here because those functions read
82 * the flags from the primary mmd structure, so calling them from command
83 * handler context would require to take the mmd lock. At the time the function
84 * is called we already took a copy of the mmd structure and want to use the
85 * flags value of the copy for computing the vss status text.
87 static char *vss_status_tohuman(unsigned int flags
)
89 if (flags
& VSS_PLAYING
)
90 return para_strdup("playing");
92 return para_strdup("stopped");
93 return para_strdup("paused");
97 * return human readable permission string. Never returns NULL.
99 static char *cmd_perms_itohuman(unsigned int perms
)
101 char *msg
= para_malloc(5 * sizeof(char));
103 msg
[0] = perms
& AFS_READ
? 'a' : '-';
104 msg
[1] = perms
& AFS_WRITE
? 'A' : '-';
105 msg
[2] = perms
& VSS_READ
? 'v' : '-';
106 msg
[3] = perms
& VSS_WRITE
? 'V' : '-';
112 * Never returns NULL.
114 static char *vss_get_status_flags(unsigned int flags
)
116 char *msg
= para_malloc(5 * sizeof(char));
118 msg
[0] = (flags
& VSS_PLAYING
)? 'P' : '_';
119 msg
[1] = (flags
& VSS_NOMORE
)? 'O' : '_';
120 msg
[2] = (flags
& VSS_NEXT
)? 'N' : '_';
121 msg
[3] = (flags
& VSS_REPOS
)? 'R' : '_';
126 static unsigned get_status(struct misc_meta_data
*nmmd
, int parser_friendly
,
129 char *status
, *flags
; /* vss status info */
130 /* nobody updates our version of "now" */
131 long offset
= (nmmd
->offset
+ 500) / 1000;
132 struct timeval current_time
;
133 struct para_buffer b
= {.flags
= parser_friendly
? PBF_SIZE_PREFIX
: 0};
135 /* report real status */
136 status
= vss_status_tohuman(nmmd
->vss_status_flags
);
137 flags
= vss_get_status_flags(nmmd
->vss_status_flags
);
138 clock_get_realtime(¤t_time
);
140 * The calls to WRITE_STATUS_ITEM() below never fail because
141 * b->max_size is zero (unlimited), see para_printf(). However, clang
142 * is not smart enough to prove this and complains nevertheless.
143 * Casting the return value to void silences clang.
145 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS
, "%s\n", status
);
146 (void)WRITE_STATUS_ITEM(&b
, SI_STATUS_FLAGS
, "%s\n", flags
);
147 (void)WRITE_STATUS_ITEM(&b
, SI_OFFSET
, "%li\n", offset
);
148 (void)WRITE_STATUS_ITEM(&b
, SI_AFS_MODE
, "%s\n", mmd
->afs_mode_string
);
149 (void)WRITE_STATUS_ITEM(&b
, SI_STREAM_START
, "%lu.%lu\n",
150 (long unsigned)nmmd
->stream_start
.tv_sec
,
151 (long unsigned)nmmd
->stream_start
.tv_usec
);
152 (void)WRITE_STATUS_ITEM(&b
, SI_CURRENT_TIME
, "%lu.%lu\n",
153 (long unsigned)current_time
.tv_sec
,
154 (long unsigned)current_time
.tv_usec
);
161 static int check_sender_args(int argc
, char * const * argv
, struct sender_command_data
*scd
)
164 /* this has to match sender.h */
165 const char *subcmds
[] = {"add", "delete", "allow", "deny", "on", "off", NULL
};
167 scd
->sender_num
= -1;
169 return -E_COMMAND_SYNTAX
;
170 for (i
= 0; senders
[i
].name
; i
++)
171 if (!strcmp(senders
[i
].name
, argv
[1]))
173 PARA_DEBUG_LOG("%d:%s\n", argc
, argv
[1]);
174 if (!senders
[i
].name
)
175 return -E_COMMAND_SYNTAX
;
177 for (i
= 0; subcmds
[i
]; i
++)
178 if (!strcmp(subcmds
[i
], argv
[2]))
181 return -E_COMMAND_SYNTAX
;
183 if (!senders
[scd
->sender_num
].client_cmds
[scd
->cmd_num
])
184 return -E_SENDER_CMD
;
185 switch (scd
->cmd_num
) {
189 return -E_COMMAND_SYNTAX
;
193 if (argc
!= 4 || parse_cidr(argv
[3], scd
->host
,
194 sizeof(scd
->host
), &scd
->netmask
) == NULL
)
195 return -E_COMMAND_SYNTAX
;
200 return -E_COMMAND_SYNTAX
;
201 return parse_fec_url(argv
[3], scd
);
203 return -E_COMMAND_SYNTAX
;
209 * Send a sideband packet through a blocking file descriptor.
211 * \param scc fd and crypto keys.
212 * \param buf The buffer to send.
213 * \param numbytes The size of \a buf.
214 * \param band The sideband designator of this packet.
215 * \param dont_free If true, never deallocate \a buf.
217 * The nonblock flag must be disabled for the file descriptor given by \a scc.
219 * Stream cipher encryption is automatically activated if necessary via the
220 * sideband transformation, depending on the value of \a band.
224 * \sa \ref send_sb_va().
226 int send_sb(struct stream_cipher_context
*scc
, void *buf
, size_t numbytes
,
227 int band
, bool dont_free
)
230 struct sb_context
*sbc
;
232 sb_transformation trafo
= band
< SBD_PROCEED
? NULL
: sc_trafo
;
233 struct sb_buffer sbb
= SBB_INIT(band
, buf
, numbytes
);
235 sbc
= sb_new_send(&sbb
, dont_free
, trafo
, scc
->send
);
237 ret
= sb_get_send_buffers(sbc
, iov
);
238 ret
= xwritev(scc
->fd
, iov
, ret
);
241 } while (sb_sent(sbc
, ret
) == false);
249 * Create a variable sized buffer and send it as a sideband packet.
251 * \param scc Passed to \ref send_sb.
252 * \param band See \ref send_sb.
253 * \param fmt The format string.
255 * \return The return value of the underlying call to \ref send_sb.
257 __printf_3_4
int send_sb_va(struct stream_cipher_context
*scc
, int band
,
258 const char *fmt
, ...)
265 ret
= xvasprintf(&msg
, fmt
, ap
);
267 return send_sb(scc
, msg
, ret
, band
, false);
271 * Send an error message to a client.
273 * \param cc Client info.
274 * \param err The (positive) error code.
276 * \return The return value of the underlying call to send_sb_va().
278 int send_strerror(struct command_context
*cc
, int err
)
280 return send_sb_va(&cc
->scc
, SBD_ERROR_LOG
, "%s\n", para_strerror(err
));
284 * Send a sideband packet through a blocking file descriptor.
286 * \param scc fd and crypto keys.
287 * \param expected_band The expected band designator.
288 * \param max_size Passed to \ref sb_new_recv().
289 * \param result Body of the sideband packet is returned here.
291 * If \a expected_band is not \p SBD_ANY, the band designator of the received
292 * sideband packet is compared to \a expected_band and a mismatch is considered
297 int recv_sb(struct stream_cipher_context
*scc
,
298 enum sb_designator expected_band
,
299 size_t max_size
, struct iovec
*result
)
302 struct sb_context
*sbc
;
304 struct sb_buffer sbb
;
305 sb_transformation trafo
;
307 trafo
= expected_band
!= SBD_ANY
&& expected_band
< SBD_PROCEED
?
309 sbc
= sb_new_recv(max_size
, trafo
, scc
->recv
);
311 sb_get_recv_buffer(sbc
, &iov
);
312 ret
= recv_bin_buffer(scc
->fd
, iov
.iov_base
, iov
.iov_len
);
317 ret
= sb_received(sbc
, ret
, &sbb
);
324 if (expected_band
!= SBD_ANY
&& sbb
.band
!= expected_band
)
333 static int com_sender(struct command_context
*cc
)
337 struct sender_command_data scd
;
340 for (i
= 0; senders
[i
].name
; i
++) {
342 ret
= xasprintf(&tmp
, "%s%s\n", msg
? msg
: "",
347 return send_sb(&cc
->scc
, msg
, ret
, SBD_OUTPUT
, false);
349 ret
= check_sender_args(cc
->argc
, cc
->argv
, &scd
);
351 if (scd
.sender_num
< 0)
353 if (strcmp(cc
->argv
[2], "status") == 0)
354 msg
= senders
[scd
.sender_num
].status();
356 msg
= senders
[scd
.sender_num
].help();
357 return send_sb(&cc
->scc
, msg
, strlen(msg
), SBD_OUTPUT
, false);
360 switch (scd
.cmd_num
) {
363 assert(senders
[scd
.sender_num
].resolve_target
);
364 ret
= senders
[scd
.sender_num
].resolve_target(cc
->argv
[3], &scd
);
369 for (i
= 0; i
< 10; i
++) {
370 mutex_lock(mmd_mutex
);
371 if (mmd
->sender_cmd_data
.cmd_num
>= 0) {
372 /* another sender command is active, retry in 100ms */
373 struct timespec ts
= {.tv_nsec
= 100 * 1000 * 1000};
374 mutex_unlock(mmd_mutex
);
375 nanosleep(&ts
, NULL
);
378 mmd
->sender_cmd_data
= scd
;
379 mutex_unlock(mmd_mutex
);
382 return (i
< 10)? 1 : -E_LOCK
;
386 static int com_si(struct command_context
*cc
)
392 return -E_COMMAND_SYNTAX
;
393 mutex_lock(mmd_mutex
);
394 ut
= daemon_get_uptime_str(now
);
395 ret
= xasprintf(&msg
,
396 "up: %s\nplayed: %u\n"
399 "connections (active/accepted/total): %u/%u/%u\n"
400 "current loglevel: %s\n"
401 "supported audio formats: %s\n",
405 mmd
->active_connections
,
409 AUDIO_FORMAT_HANDLERS
411 mutex_unlock(mmd_mutex
);
413 return send_sb(&cc
->scc
, msg
, ret
, SBD_OUTPUT
, false);
417 static int com_version(struct command_context
*cc
)
422 if (cc
->argc
> 1 && strcmp(cc
->argv
[1], "-v") == 0)
423 len
= xasprintf(&msg
, "%s", version_text("server"));
425 len
= xasprintf(&msg
, "%s\n", version_single_line("server"));
426 return send_sb(&cc
->scc
, msg
, len
, SBD_OUTPUT
, false);
429 /** These status items are cleared if no audio file is currently open. */
430 #define EMPTY_STATUS_ITEMS \
435 ITEM(ATTRIBUTES_BITMAP) \
436 ITEM(ATTRIBUTES_TXT) \
447 ITEM(SECONDS_TOTAL) \
460 ITEM(AMPLIFICATION) \
463 * Write a list of audio-file related status items with empty values.
465 * This is used by vss when currently no audio file is open.
467 static unsigned empty_status_items(int parser_friendly
, char **result
)
473 len
= xasprintf(&esi
,
474 #define ITEM(x) "0004 %02x:\n"
477 #define ITEM(x) , SI_ ## x
482 len
= xasprintf(&esi
,
483 #define ITEM(x) "%s:\n"
486 #define ITEM(x) ,status_item_list[SI_ ## x]
493 #undef EMPTY_STATUS_ITEMS
496 static int com_stat(struct command_context
*cc
)
499 struct misc_meta_data tmp
, *nmmd
= &tmp
;
502 int parser_friendly
= 0;
504 para_sigaction(SIGUSR1
, dummy
);
506 for (i
= 1; i
< cc
->argc
; i
++) {
507 const char *arg
= cc
->argv
[i
];
510 if (!strcmp(arg
, "--")) {
514 if (!strncmp(arg
, "-n=", 3)) {
515 ret
= para_atoi32(arg
+ 3, &num
);
520 if (!strcmp(arg
, "-p")) {
524 return -E_COMMAND_SYNTAX
;
527 return -E_COMMAND_SYNTAX
;
530 * Copy the mmd structure to minimize the time we hold the mmd
533 mutex_lock(mmd_mutex
);
535 mutex_unlock(mmd_mutex
);
536 ret
= get_status(nmmd
, parser_friendly
, &s
);
537 ret
= send_sb(&cc
->scc
, s
, ret
, SBD_OUTPUT
, false);
540 if (nmmd
->vss_status_flags
& VSS_NEXT
) {
542 ret
= empty_status_items(parser_friendly
, &esi
);
543 ret
= send_sb(&cc
->scc
, esi
, ret
, SBD_OUTPUT
, false);
547 send_afs_status(cc
, parser_friendly
);
549 if (num
> 0 && !--num
)
552 ret
= -E_SERVER_CRASH
;
560 static int send_list_of_commands(struct command_context
*cc
, struct server_command
*cmd
,
565 for (; cmd
->name
; cmd
++) {
566 char *tmp
, *perms
= cmd_perms_itohuman(cmd
->perms
);
567 tmp
= make_message("%s\t%s\t%s\t%s\n", cmd
->name
, handler
,
568 perms
, cmd
->description
);
570 msg
= para_strcat(msg
, tmp
);
574 return send_sb(&cc
->scc
, msg
, strlen(msg
), SBD_OUTPUT
, false);
577 /* returns string that must be freed by the caller */
578 static struct server_command
*get_cmd_ptr(const char *name
, char **handler
)
580 struct server_command
*cmd
;
582 for (cmd
= server_cmds
; cmd
->name
; cmd
++)
583 if (!strcmp(cmd
->name
, name
)) {
585 *handler
= para_strdup("server"); /* server commands */
588 /* not found, look for commands supported by afs */
589 for (cmd
= afs_cmds
; cmd
->name
; cmd
++)
590 if (!strcmp(cmd
->name
, name
)) {
592 *handler
= para_strdup("afs");
599 static int com_help(struct command_context
*cc
)
601 struct server_command
*cmd
;
602 char *perms
, *handler
, *buf
;
606 /* no argument given, print list of commands */
607 if ((ret
= send_list_of_commands(cc
, server_cmds
, "server")) < 0)
609 return send_list_of_commands(cc
, afs_cmds
, "afs");
611 /* argument given for help */
612 cmd
= get_cmd_ptr(cc
->argv
[1], &handler
);
615 perms
= cmd_perms_itohuman(cmd
->perms
);
616 ret
= xasprintf(&buf
, "%s - %s\n\n"
630 return send_sb(&cc
->scc
, buf
, ret
, SBD_OUTPUT
, false);
634 static int com_hup(struct command_context
*cc
)
637 return -E_COMMAND_SYNTAX
;
638 kill(getppid(), SIGHUP
);
643 static int com_term(struct command_context
*cc
)
646 return -E_COMMAND_SYNTAX
;
647 kill(getppid(), SIGTERM
);
651 static int com_play(struct command_context
*cc
)
654 return -E_COMMAND_SYNTAX
;
655 mutex_lock(mmd_mutex
);
656 mmd
->new_vss_status_flags
|= VSS_PLAYING
;
657 mmd
->new_vss_status_flags
&= ~VSS_NOMORE
;
658 mutex_unlock(mmd_mutex
);
663 static int com_stop(struct command_context
*cc
)
666 return -E_COMMAND_SYNTAX
;
667 mutex_lock(mmd_mutex
);
668 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
669 mmd
->new_vss_status_flags
&= ~VSS_REPOS
;
670 mmd
->new_vss_status_flags
|= VSS_NEXT
;
671 mutex_unlock(mmd_mutex
);
676 static int com_pause(struct command_context
*cc
)
679 return -E_COMMAND_SYNTAX
;
680 mutex_lock(mmd_mutex
);
681 if (!vss_paused() && !vss_stopped()) {
683 mmd
->new_vss_status_flags
&= ~VSS_PLAYING
;
684 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
686 mutex_unlock(mmd_mutex
);
691 static int com_next(struct command_context
*cc
)
694 return -E_COMMAND_SYNTAX
;
695 mutex_lock(mmd_mutex
);
697 mmd
->new_vss_status_flags
|= VSS_NEXT
;
698 mutex_unlock(mmd_mutex
);
703 static int com_nomore(struct command_context
*cc
)
706 return -E_COMMAND_SYNTAX
;
707 mutex_lock(mmd_mutex
);
708 if (vss_playing() || vss_paused())
709 mmd
->new_vss_status_flags
|= VSS_NOMORE
;
710 mutex_unlock(mmd_mutex
);
715 static int com_ff(struct command_context
*cc
)
718 int ret
, backwards
= 0;
723 return -E_COMMAND_SYNTAX
;
724 if (!(ret
= sscanf(cc
->argv
[1], "%u%c", &i
, &c
)))
725 return -E_COMMAND_SYNTAX
;
726 if (ret
> 1 && c
== '-')
727 backwards
= 1; /* jmp backwards */
728 mutex_lock(mmd_mutex
);
729 ret
= -E_NO_AUDIO_FILE
;
730 if (!mmd
->afd
.afhi
.chunks_total
|| !mmd
->afd
.afhi
.seconds_total
)
732 promille
= (1000 * mmd
->current_chunk
) / mmd
->afd
.afhi
.chunks_total
;
734 promille
-= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
736 promille
+= 1000 * i
/ mmd
->afd
.afhi
.seconds_total
;
739 if (promille
> 1000) {
740 mmd
->new_vss_status_flags
|= VSS_NEXT
;
743 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* promille
) / 1000;
744 mmd
->new_vss_status_flags
|= VSS_REPOS
;
745 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
749 mutex_unlock(mmd_mutex
);
754 static int com_jmp(struct command_context
*cc
)
760 return -E_COMMAND_SYNTAX
;
761 if (sscanf(cc
->argv
[1], "%lu", &i
) <= 0)
762 return -E_COMMAND_SYNTAX
;
763 mutex_lock(mmd_mutex
);
764 ret
= -E_NO_AUDIO_FILE
;
765 if (!mmd
->afd
.afhi
.chunks_total
)
769 PARA_INFO_LOG("jumping to %lu%%\n", i
);
770 mmd
->repos_request
= (mmd
->afd
.afhi
.chunks_total
* i
+ 50) / 100;
771 PARA_INFO_LOG("sent: %lu, offset before jmp: %lu\n",
772 mmd
->chunks_sent
, mmd
->offset
);
773 mmd
->new_vss_status_flags
|= VSS_REPOS
;
774 mmd
->new_vss_status_flags
&= ~VSS_NEXT
;
778 mutex_unlock(mmd_mutex
);
782 static int com_tasks(struct command_context
*cc
)
784 char *tl
= server_get_tasks();
788 ret
= send_sb(&cc
->scc
, tl
, strlen(tl
), SBD_OUTPUT
, false);
793 * check if perms are sufficient to exec a command having perms cmd_perms.
794 * Returns 0 if perms are sufficient, -E_PERM otherwise.
796 static int check_perms(unsigned int perms
, const struct server_command
*cmd_ptr
)
798 PARA_DEBUG_LOG("checking permissions\n");
799 return (cmd_ptr
->perms
& perms
) < cmd_ptr
->perms
? -E_PERM
: 0;
802 static void reset_signals(void)
804 para_sigaction(SIGCHLD
, SIG_IGN
);
805 para_sigaction(SIGINT
, SIG_DFL
);
806 para_sigaction(SIGTERM
, SIG_DFL
);
807 para_sigaction(SIGHUP
, SIG_DFL
);
810 struct connection_features
{
811 bool sideband_requested
;
812 bool aes_ctr128_requested
;
815 static int parse_auth_request(char *buf
, int len
, struct user
**u
,
816 struct connection_features
*cf
)
819 char *p
, *username
, **features
= NULL
;
820 size_t auth_rq_len
= strlen(AUTH_REQUEST_MSG
);
823 memset(cf
, 0, sizeof(*cf
));
824 if (len
< auth_rq_len
+ 2)
825 return -E_AUTH_REQUEST
;
826 if (strncmp(buf
, AUTH_REQUEST_MSG
, auth_rq_len
) != 0)
827 return -E_AUTH_REQUEST
;
828 username
= buf
+ auth_rq_len
;
829 p
= strchr(username
, ' ');
833 return -E_AUTH_REQUEST
;
836 create_argv(p
, ",", &features
);
837 for (i
= 0; features
[i
]; i
++) {
838 if (strcmp(features
[i
], "sideband") == 0)
839 cf
->sideband_requested
= true;
840 else if (strcmp(features
[i
], "aes_ctr128") == 0)
841 cf
->aes_ctr128_requested
= true;
843 ret
= -E_BAD_FEATURE
;
848 PARA_DEBUG_LOG("received auth request for user %s\n", username
);
849 *u
= lookup_user(username
);
856 #define HANDSHAKE_BUFSIZE 4096
858 static int run_command(struct command_context
*cc
, struct iovec
*iov
,
859 const char *peername
)
863 struct server_command
*cmd
;
865 if (iov
->iov_base
== NULL
|| iov
->iov_len
== 0)
868 p
[iov
->iov_len
- 1] = '\0'; /* just to be sure */
869 cmd
= get_cmd_ptr(p
, NULL
);
872 ret
= check_perms(cc
->u
->perms
, cmd
);
875 end
= iov
->iov_base
+ iov
->iov_len
;
876 for (i
= 0; p
< end
; i
++)
879 cc
->argv
= para_malloc((cc
->argc
+ 1) * sizeof(char *));
880 for (i
= 0, p
= iov
->iov_base
; p
< end
; i
++) {
881 cc
->argv
[i
] = para_strdup(p
);
884 cc
->argv
[cc
->argc
] = NULL
;
885 PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd
->name
,
886 cc
->u
->name
, peername
);
887 ret
= cmd
->handler(cc
);
889 mutex_lock(mmd_mutex
);
891 if (ret
>= 0 && (cmd
->perms
& AFS_WRITE
))
893 mutex_unlock(mmd_mutex
);
898 * Perform user authentication and execute a command.
900 * \param fd The file descriptor to send output to.
901 * \param peername Identifies the connecting peer.
903 * Whenever para_server accepts an incoming tcp connection on the port it
904 * listens on, it forks and the resulting child calls this function.
906 * An RSA-based challenge/response is used to authenticate the peer. It that
907 * authentication succeeds, a random session key is generated and sent back to
908 * the peer, encrypted with its RSA public key. From this point on, all
909 * transfers are crypted with this session key.
911 * Next it is checked if the peer supplied a valid server command or a command
912 * for the audio file selector. If yes, and if the user has sufficient
913 * permissions to execute that command, the function calls the corresponding
914 * command handler which does argument checking and further processing.
916 * In order to cope with a DOS attacks, a timeout is set up which terminates
917 * the function if the connection was not authenticated when the timeout
920 * \sa alarm(2), crypt.c, crypt.h
922 __noreturn
void handle_connect(int fd
, const char *peername
)
925 unsigned char rand_buf
[CHALLENGE_SIZE
+ 2 * SESSION_KEY_LEN
];
926 unsigned char challenge_hash
[HASH_SIZE
];
927 char *command
= NULL
, *buf
= para_malloc(HANDSHAKE_BUFSIZE
) /* must be on the heap */;
929 struct command_context cc_struct
= {.peer
= peername
}, *cc
= &cc_struct
;
931 struct connection_features cf
;
935 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
936 ret
= mark_fd_blocking(fd
);
939 /* send Welcome message */
940 ret
= write_va_buffer(fd
, "This is para_server, version "
941 PACKAGE_VERSION
".\n"
942 "Features: sideband,aes_ctr128\n"
946 /* recv auth request line */
947 ret
= recv_buffer(fd
, buf
, HANDSHAKE_BUFSIZE
);
950 ret
= parse_auth_request(buf
, ret
, &cc
->u
, &cf
);
953 if (!cf
.sideband_requested
) { /* sideband is mandatory */
954 PARA_ERROR_LOG("client did not request sideband\n");
955 ret
= -E_BAD_FEATURE
;
959 get_random_bytes_or_die(rand_buf
, sizeof(rand_buf
));
960 ret
= pub_encrypt(cc
->u
->pubkey
, rand_buf
, sizeof(rand_buf
),
961 (unsigned char *)buf
);
967 * We don't want to reveal our user names, so we send a
968 * challenge to the client even if the user does not exist, and
969 * fail the authentication later.
972 get_random_bytes_or_die((unsigned char *)buf
, numbytes
);
974 PARA_DEBUG_LOG("sending %u byte challenge + session key (%zu bytes)\n",
975 CHALLENGE_SIZE
, numbytes
);
976 ret
= send_sb(&cc
->scc
, buf
, numbytes
, SBD_CHALLENGE
, false);
980 ret
= recv_sb(&cc
->scc
, SBD_CHALLENGE_RESPONSE
,
981 HANDSHAKE_BUFSIZE
, &iov
);
985 numbytes
= iov
.iov_len
;
986 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes
);
991 * The correct response is the hash of the first CHALLENGE_SIZE bytes
992 * of the random data.
995 if (numbytes
!= HASH_SIZE
)
997 hash_function((char *)rand_buf
, CHALLENGE_SIZE
, challenge_hash
);
998 if (memcmp(challenge_hash
, buf
, HASH_SIZE
))
1000 /* auth successful */
1002 PARA_INFO_LOG("good auth for %s\n", cc
->u
->name
);
1003 /* init stream cipher keys with the second part of the random buffer */
1004 cc
->scc
.recv
= sc_new(rand_buf
+ CHALLENGE_SIZE
, SESSION_KEY_LEN
,
1005 cf
.aes_ctr128_requested
);
1006 cc
->scc
.send
= sc_new(rand_buf
+ CHALLENGE_SIZE
+ SESSION_KEY_LEN
,
1007 SESSION_KEY_LEN
, cf
.aes_ctr128_requested
);
1008 ret
= send_sb(&cc
->scc
, NULL
, 0, SBD_PROCEED
, false);
1011 ret
= recv_sb(&cc
->scc
, SBD_COMMAND
, MAX_COMMAND_LEN
, &iov
);
1014 ret
= run_command(cc
, &iov
, peername
);
1021 if (send_strerror(cc
, -ret
) >= 0)
1022 send_sb(&cc
->scc
, NULL
, 0, SBD_EXIT__FAILURE
, true);
1024 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
1028 mutex_lock(mmd_mutex
);
1029 mmd
->active_connections
--;
1030 mutex_unlock(mmd_mutex
);
1032 ret
= send_sb(&cc
->scc
, NULL
, 0, SBD_EXIT__SUCCESS
, true);
1034 PARA_NOTICE_LOG("%s\n", para_strerror(-ret
));
1036 sc_free(cc
->scc
.recv
);
1037 sc_free(cc
->scc
.send
);
1038 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);