1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file command.c Client authentication and server commands. */
5 #include <netinet/in.h>
6 #include <sys/socket.h>
13 #include "server.lsg.h"
31 #include "server_cmd.lsg.h"
32 #include "user_list.h"
36 #define SERVER_CMD_AUX_INFO(_arg) _arg,
37 static const unsigned server_command_perms[] = {LSG_SERVER_CMD_AUX_INFOS};
38 #undef SERVER_CMD_AUX_INFO
39 #define SERVER_CMD_AUX_INFO(_arg) #_arg,
40 static const char * const server_command_perms_txt[] = {LSG_SERVER_CMD_AUX_INFOS};
41 #undef SERVER_CMD_AUX_INFO
43 /** Commands including options must be shorter than this. */
44 #define MAX_COMMAND_LEN 32768
47 extern struct misc_meta_data *mmd;
48 int send_afs_status(struct command_context *cc, int parser_friendly);
49 static bool subcmd_should_die;
51 static void command_handler_sighandler(int s)
55 PARA_EMERG_LOG("terminating on signal %d\n", SIGTERM);
56 subcmd_should_die = true;
60 * Compute human readable vss status text.
62 * We can't call vss_playing() and friends here because those functions read
63 * the flags from the primary mmd structure, so calling them from command
64 * handler context would require to take the mmd lock. At the time the function
65 * is called we already took a copy of the mmd structure and want to use the
66 * flags value of the copy for computing the vss status text.
68 static char *vss_status_tohuman(unsigned int flags)
70 if (flags & VSS_PLAYING)
71 return para_strdup("playing");
73 return para_strdup("stopped");
74 return para_strdup("paused");
80 static char *vss_get_status_flags(unsigned int flags)
82 char *msg = para_malloc(5 * sizeof(char));
84 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
85 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
86 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
87 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
92 static unsigned get_status(struct misc_meta_data *nmmd, bool parser_friendly,
95 char *status, *flags; /* vss status info */
96 /* nobody updates our version of "now" */
97 long offset = (nmmd->offset + 500) / 1000;
98 struct timeval current_time;
99 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
101 /* report real status */
102 status = vss_status_tohuman(nmmd->vss_status_flags);
103 flags = vss_get_status_flags(nmmd->vss_status_flags);
104 clock_get_realtime(¤t_time);
106 * The calls to WRITE_STATUS_ITEM() below never fail because
107 * b->max_size is zero (unlimited), see \ref para_printf(). However,
108 * clang is not smart enough to prove this and complains nevertheless.
109 * Casting the return value to void silences clang.
111 (void)WRITE_STATUS_ITEM(&b, SI_status, "%s\n", status);
112 (void)WRITE_STATUS_ITEM(&b, SI_status_flags, "%s\n", flags);
113 (void)WRITE_STATUS_ITEM(&b, SI_offset, "%li\n", offset);
114 (void)WRITE_STATUS_ITEM(&b, SI_afs_mode, "%s\n", mmd->afs_mode_string);
115 (void)WRITE_STATUS_ITEM(&b, SI_stream_start, "%lu.%lu\n",
116 (long unsigned)nmmd->stream_start.tv_sec,
117 (long unsigned)nmmd->stream_start.tv_usec);
118 (void)WRITE_STATUS_ITEM(&b, SI_current_time, "%lu.%lu\n",
119 (long unsigned)current_time.tv_sec,
120 (long unsigned)current_time.tv_usec);
128 * Send a sideband packet through a blocking file descriptor.
130 * \param scc fd and crypto keys.
131 * \param buf The buffer to send.
132 * \param numbytes The size of \a buf.
133 * \param band The sideband designator of this packet.
134 * \param dont_free If true, never deallocate \a buf.
136 * The nonblock flag must be disabled for the file descriptor given by \a scc.
138 * Stream cipher encryption is automatically activated if necessary via the
139 * sideband transformation, depending on the value of \a band.
143 * \sa \ref send_sb_va().
145 int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
146 int band, bool dont_free)
149 struct sb_context *sbc;
151 sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
152 struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
154 sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
156 ret = sb_get_send_buffers(sbc, iov);
157 ret = xwritev(scc->fd, iov, ret);
160 } while (sb_sent(sbc, ret) == false);
168 * Create a variable sized buffer and send it as a sideband packet.
170 * \param scc Passed to \ref send_sb.
171 * \param band See \ref send_sb.
172 * \param fmt The format string.
174 * \return The return value of the underlying call to \ref send_sb.
176 __printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
177 const char *fmt, ...)
184 ret = xvasprintf(&msg, fmt, ap);
186 return send_sb(scc, msg, ret, band, false);
190 * Send an error message to a client.
192 * \param cc Client info.
193 * \param err The (positive) error code.
195 * \return The return value of the underlying call to send_sb_va().
197 int send_strerror(struct command_context *cc, int err)
199 return send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err));
203 * Send an error context to a client,
205 * \param cc Client info.
206 * \param errctx The error context string.
208 * \return The return value of the underlying call to send_sb_va().
210 * This function frees the error context string after it was sent.
212 int send_errctx(struct command_context *cc, char *errctx)
218 ret = send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", errctx);
223 static int check_sender_args(struct command_context *cc,
224 struct lls_parse_result *lpr, struct sender_command_data *scd)
227 const char * const subcmds[] = {SENDER_SUBCOMMANDS};
230 unsigned num_inputs = lls_num_inputs(lpr);
232 scd->sender_num = -1;
233 ret = lls(lls_check_arg_count(lpr, 2, INT_MAX, &errctx));
235 send_errctx(cc, errctx);
238 arg = lls_input(0, lpr);
240 if (strcmp(senders[i]->name, arg) == 0)
243 return -E_COMMAND_SYNTAX;
245 arg = lls_input(1, lpr);
246 for (i = 0; i < NUM_SENDER_CMDS; i++)
247 if (!strcmp(subcmds[i], arg))
249 if (i == NUM_SENDER_CMDS)
250 return -E_COMMAND_SYNTAX;
252 if (!senders[scd->sender_num]->client_cmds[scd->cmd_num])
253 return -E_SENDER_CMD;
254 switch (scd->cmd_num) {
258 return -E_COMMAND_SYNTAX;
262 if (num_inputs != 3 || parse_cidr(lls_input(2, lpr), scd->host,
263 sizeof(scd->host), &scd->netmask) == NULL)
264 return -E_COMMAND_SYNTAX;
269 return -E_COMMAND_SYNTAX;
270 return parse_fec_url(lls_input(2, lpr), scd);
272 return -E_COMMAND_SYNTAX;
278 * Receive a sideband packet from a blocking file descriptor.
280 * \param scc fd and crypto keys.
281 * \param expected_band The expected band designator.
282 * \param max_size Passed to \ref sb_new_recv().
283 * \param result Body of the sideband packet is returned here.
285 * If \a expected_band is not \p SBD_ANY, the band designator of the received
286 * sideband packet is compared to \a expected_band and a mismatch is considered
291 int recv_sb(struct stream_cipher_context *scc,
292 enum sb_designator expected_band,
293 size_t max_size, struct iovec *result)
296 struct sb_context *sbc;
298 struct sb_buffer sbb;
299 sb_transformation trafo;
301 trafo = expected_band != SBD_ANY && expected_band < SBD_PROCEED?
303 sbc = sb_new_recv(max_size, trafo, scc->recv);
305 sb_get_recv_buffer(sbc, &iov);
306 ret = recv_bin_buffer(scc->fd, iov.iov_base, iov.iov_len);
311 ret = sb_received(sbc, ret, &sbb);
318 if (expected_band != SBD_ANY && sbb.band != expected_band)
327 static int com_sender(struct command_context *cc, struct lls_parse_result *lpr)
331 struct sender_command_data scd;
333 if (lls_num_inputs(lpr) == 0) {
336 ret = xasprintf(&tmp, "%s%s\n", msg? msg : "",
341 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
343 ret = check_sender_args(cc, lpr, &scd);
345 if (scd.sender_num < 0)
347 if (strcmp(lls_input(1, lpr), "status") == 0)
348 msg = senders[scd.sender_num]->status();
350 msg = senders[scd.sender_num]->help();
351 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
354 switch (scd.cmd_num) {
357 assert(senders[scd.sender_num]->resolve_target);
358 ret = senders[scd.sender_num]->resolve_target(lls_input(2, lpr),
364 for (i = 0; i < 10; i++) {
365 mutex_lock(mmd_mutex);
366 if (mmd->sender_cmd_data.cmd_num >= 0) {
367 /* another sender command is active, retry in 100ms */
368 struct timespec ts = {.tv_nsec = 100 * 1000 * 1000};
369 mutex_unlock(mmd_mutex);
370 nanosleep(&ts, NULL);
373 mmd->sender_cmd_data = scd;
374 mutex_unlock(mmd_mutex);
377 return (i < 10)? 1 : -E_LOCK;
379 EXPORT_SERVER_CMD_HANDLER(sender);
381 static int com_si(struct command_context *cc,
382 __a_unused struct lls_parse_result *lpr)
387 ut = daemon_get_uptime_str(now);
388 mutex_lock(mmd_mutex);
389 ret = xasprintf(&msg,
390 "up: %s\nplayed: %u\n"
393 "connections (active/accepted/total): %u/%u/%u\n"
394 "current loglevel: %s\n"
395 "supported audio formats: %s\n",
399 mmd->active_connections,
402 ENUM_STRING_VAL(LOGLEVEL),
403 AUDIO_FORMAT_HANDLERS
405 mutex_unlock(mmd_mutex);
407 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
409 EXPORT_SERVER_CMD_HANDLER(si);
411 static int com_version(struct command_context *cc, struct lls_parse_result *lpr)
416 if (SERVER_CMD_OPT_GIVEN(VERSION, VERBOSE, lpr))
417 len = xasprintf(&msg, "%s", version_text("server"));
419 len = xasprintf(&msg, "%s\n", version_single_line("server"));
420 return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
422 EXPORT_SERVER_CMD_HANDLER(version);
424 /** These status items are cleared if no audio file is currently open. */
425 #define EMPTY_STATUS_ITEMS \
430 ITEM(attributes_bitmap) \
431 ITEM(attributes_txt) \
442 ITEM(seconds_total) \
455 ITEM(amplification) \
459 * Create a set of audio-file related status items with empty values. These are
460 * written to stat clients when no audio file is open.
462 static unsigned empty_status_items(bool parser_friendly, char **result)
468 len = xasprintf(&esi,
469 #define ITEM(x) "0004 %02x:\n"
472 #define ITEM(x) , (unsigned) SI_ ## x
477 len = xasprintf(&esi,
478 #define ITEM(x) "%s:\n"
481 #define ITEM(x) ,status_item_list[SI_ ## x]
488 #undef EMPTY_STATUS_ITEMS
490 static int com_stat(struct command_context *cc, struct lls_parse_result *lpr)
493 struct misc_meta_data tmp, *nmmd = &tmp;
495 bool parser_friendly = SERVER_CMD_OPT_GIVEN(STAT, PARSER_FRIENDLY,
497 uint32_t num = SERVER_CMD_UINT32_VAL(STAT, NUM, lpr);
498 const struct timespec ts = {.tv_sec = 50, .tv_nsec = 0};
500 para_sigaction(SIGINT, SIG_IGN);
501 para_sigaction(SIGUSR1, command_handler_sighandler);
502 para_sigaction(SIGTERM, command_handler_sighandler);
504 * Simply checking subcmd_should_die is racy because a signal may
505 * arrive after the check but before the subsequent call to sleep(3).
506 * If this happens, sleep(3) would not be interrupted by the signal.
507 * To avoid this we block SIGTERM here and allow it to arrive only
510 para_block_signal(SIGTERM);
514 * Copy the mmd structure to minimize the time we hold the mmd
517 mutex_lock(mmd_mutex);
519 mutex_unlock(mmd_mutex);
520 ret = get_status(nmmd, parser_friendly, &s);
521 ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
524 if (nmmd->vss_status_flags & VSS_NEXT) {
526 ret = empty_status_items(parser_friendly, &esi);
527 ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT, false);
531 send_afs_status(cc, parser_friendly);
533 if (num > 0 && !--num)
535 sigemptyset(&set); /* empty set means: unblock all signals */
537 * pselect(2) allows to atomically unblock signals, then go to
538 * sleep. Calling sigprocmask(2) followed by sleep(3) would
539 * open a race window similar to the one described above.
541 pselect(1, NULL, NULL, NULL, &ts, &set);
542 if (subcmd_should_die)
544 ret = -E_SERVER_CRASH;
551 EXPORT_SERVER_CMD_HANDLER(stat);
553 static const char *aux_info_cb(unsigned cmd_num, bool verbose)
555 static char result[80];
556 unsigned perms = server_command_perms[cmd_num];
559 /* permissions: VSS_READ | VSS_WRITE */
560 sprintf(result, "permissions: %s",
561 server_command_perms_txt[cmd_num]);
563 result[0] = perms & AFS_READ? 'a' : '-';
564 result[1] = perms & AFS_WRITE? 'A' : '-';
565 result[2] = perms & VSS_READ? 'v' : '-';
566 result[3] = perms & VSS_WRITE? 'V' : '-';
572 static int com_help(struct command_context *cc, struct lls_parse_result *lpr)
577 bool long_help = SERVER_CMD_OPT_GIVEN(HELP, LONG, lpr);
579 lsu_com_help(long_help, lpr, server_cmd_suite, aux_info_cb, &buf, &n);
580 ret = send_sb(&cc->scc, buf, n, SBD_OUTPUT, false);
583 EXPORT_SERVER_CMD_HANDLER(help);
585 static int com_hup(__a_unused struct command_context *cc,
586 __a_unused struct lls_parse_result *lpr)
588 kill(getppid(), SIGHUP);
591 EXPORT_SERVER_CMD_HANDLER(hup);
593 static int com_term(__a_unused struct command_context *cc,
594 __a_unused struct lls_parse_result *lpr)
596 kill(getppid(), SIGTERM);
599 EXPORT_SERVER_CMD_HANDLER(term);
601 static int com_play(__a_unused struct command_context *cc,
602 __a_unused struct lls_parse_result *lpr)
604 mutex_lock(mmd_mutex);
605 mmd->new_vss_status_flags |= VSS_PLAYING;
606 mmd->new_vss_status_flags &= ~VSS_NOMORE;
607 mutex_unlock(mmd_mutex);
610 EXPORT_SERVER_CMD_HANDLER(play);
612 static int com_stop(__a_unused struct command_context *cc,
613 __a_unused struct lls_parse_result *lpr)
615 mutex_lock(mmd_mutex);
616 mmd->new_vss_status_flags &= ~VSS_PLAYING;
617 mmd->new_vss_status_flags &= ~VSS_REPOS;
618 mmd->new_vss_status_flags |= VSS_NEXT;
619 mutex_unlock(mmd_mutex);
622 EXPORT_SERVER_CMD_HANDLER(stop);
624 static int com_pause(__a_unused struct command_context *cc,
625 __a_unused struct lls_parse_result *lpr)
627 mutex_lock(mmd_mutex);
628 if (!vss_paused() && !vss_stopped()) {
630 mmd->new_vss_status_flags &= ~VSS_PLAYING;
631 mmd->new_vss_status_flags &= ~VSS_NEXT;
633 mutex_unlock(mmd_mutex);
636 EXPORT_SERVER_CMD_HANDLER(pause);
638 static int com_next(__a_unused struct command_context *cc,
639 __a_unused struct lls_parse_result *lpr)
641 mutex_lock(mmd_mutex);
643 mmd->new_vss_status_flags |= VSS_NEXT;
644 mutex_unlock(mmd_mutex);
647 EXPORT_SERVER_CMD_HANDLER(next);
649 static int com_nomore(__a_unused struct command_context *cc,
650 __a_unused struct lls_parse_result *lpr)
652 mutex_lock(mmd_mutex);
653 if (vss_playing() || vss_paused())
654 mmd->new_vss_status_flags |= VSS_NOMORE;
655 mutex_unlock(mmd_mutex);
658 EXPORT_SERVER_CMD_HANDLER(nomore);
660 static int com_ff(struct command_context *cc, struct lls_parse_result *lpr)
666 ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
668 send_errctx(cc, errctx);
671 ret = para_atoi32(lls_input(0, lpr), &i);
673 if (ret != -E_ATOI_JUNK_AT_END)
676 * Compatibility code to keep the historic syntax (ff 30-)
677 * working. This can be removed after 0.7.0.
679 ret = sscanf(lls_input(0, lpr), "%i%c", &i, &c);
681 return -E_COMMAND_SYNTAX;
682 if (ret > 1 && c == '-') {
683 PARA_WARNING_LOG("use of obsolete syntax\n");
687 mutex_lock(mmd_mutex);
688 ret = -E_NO_AUDIO_FILE;
689 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
692 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
694 * We need this cast because without it the expression on the right
695 * hand side is of unsigned type.
697 promille += 1000 * i / (int)mmd->afd.afhi.seconds_total;
700 if (promille > 1000) {
701 mmd->new_vss_status_flags |= VSS_NEXT;
704 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
705 mmd->new_vss_status_flags |= VSS_REPOS;
706 mmd->new_vss_status_flags &= ~VSS_NEXT;
709 mutex_unlock(mmd_mutex);
712 EXPORT_SERVER_CMD_HANDLER(ff);
714 static int com_jmp(struct command_context *cc, struct lls_parse_result *lpr)
719 ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
721 send_errctx(cc, errctx);
724 if (sscanf(lls_input(0, lpr), "%d", &i) <= 0)
725 return -ERRNO_TO_PARA_ERROR(EINVAL);
726 if (i < 0 || i > 100)
727 return -ERRNO_TO_PARA_ERROR(EINVAL);
728 mutex_lock(mmd_mutex);
729 ret = -E_NO_AUDIO_FILE;
730 if (!mmd->afd.afhi.chunks_total)
732 PARA_INFO_LOG("jumping to %d%%\n", i);
733 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50) / 100;
734 mmd->new_vss_status_flags |= VSS_REPOS;
735 mmd->new_vss_status_flags &= ~VSS_NEXT;
739 mutex_unlock(mmd_mutex);
742 EXPORT_SERVER_CMD_HANDLER(jmp);
744 static void reset_signals(void)
746 para_sigaction(SIGCHLD, SIG_IGN);
747 para_sigaction(SIGINT, SIG_DFL);
748 para_sigaction(SIGTERM, SIG_DFL);
749 para_sigaction(SIGHUP, SIG_DFL);
752 struct connection_features {
753 bool sha256_requested; /* can be removed after 0.7.0 */
756 static int parse_auth_request(char *buf, int len, const struct user **u,
757 struct connection_features *cf)
760 char *p, *username, **features = NULL;
761 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
764 memset(cf, 0, sizeof(*cf));
765 if (len < auth_rq_len + 2)
766 return -E_AUTH_REQUEST;
767 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
768 return -E_AUTH_REQUEST;
769 username = buf + auth_rq_len;
770 p = strchr(username, ' ');
774 return -E_AUTH_REQUEST;
777 create_argv(p, ",", &features);
779 * Still accept sideband and AES feature requests (as a no-op)
780 * because some 0.6.x clients request them. The two checks
781 * below may be removed after 0.7.1.
783 for (i = 0; features[i]; i++) {
784 if (strcmp(features[i], "sideband") == 0)
786 if (strcmp(features[i], "aes_ctr128") == 0)
789 * ->sha256_requested can go away after 0.7.0 but the
790 * check has to stay until 0.9.0.
792 if (strcmp(features[i], "sha256") == 0)
793 cf->sha256_requested = true;
795 ret = -E_BAD_FEATURE;
800 PARA_DEBUG_LOG("received auth request for user %s\n", username);
801 *u = user_list_lookup(username);
808 #define HANDSHAKE_BUFSIZE 4096
810 static int run_command(struct command_context *cc, struct iovec *iov)
813 char *p, *end, **argv;
814 const struct lls_command *lcmd = NULL;
816 struct lls_parse_result *lpr;
819 if (iov->iov_base == NULL || iov->iov_len == 0)
820 return -ERRNO_TO_PARA_ERROR(EINVAL);
822 p[iov->iov_len - 1] = '\0'; /* just to be sure */
824 ret = lls(lls_lookup_subcmd(p, server_cmd_suite, &errctx));
826 send_errctx(cc, errctx);
829 perms = server_command_perms[ret];
830 if ((perms & cc->u->perms) != perms)
831 return -ERRNO_TO_PARA_ERROR(EPERM);
832 lcmd = lls_cmd(ret, server_cmd_suite);
833 end = iov->iov_base + iov->iov_len;
834 for (i = 0; p < end; i++)
837 argv = para_malloc((argc + 1) * sizeof(char *));
838 for (i = 0, p = iov->iov_base; p < end; i++) {
839 argv[i] = para_strdup(p);
843 PARA_NOTICE_LOG("calling com_%s() for user %s\n",
844 lls_command_name(lcmd), cc->u->name);
845 ret = lls(lls_parse(argc, argv, lcmd, &lpr, &errctx));
847 const struct server_cmd_user_data *ud = lls_user_data(lcmd);
848 ret = ud->handler(cc, lpr);
849 lls_free_parse_result(lpr, lcmd);
851 send_errctx(cc, errctx);
853 mutex_lock(mmd_mutex);
855 if (ret >= 0 && (perms & AFS_WRITE))
857 mutex_unlock(mmd_mutex);
862 * Perform user authentication and execute a command.
864 * \param fd The file descriptor to send output to.
866 * Whenever para_server accepts an incoming tcp connection on the port it
867 * listens on, it forks and the resulting child calls this function.
869 * An RSA-based challenge/response is used to authenticate the peer. If the
870 * authentication succeeds, a random session key is generated and sent back to
871 * the peer, encrypted with its RSA public key. From this point on, all
872 * transfers are encrypted with this session key using a stream cipher.
874 * Next it is checked if the peer supplied a valid server command or a command
875 * for the audio file selector. If yes, and if the user has sufficient
876 * permissions to execute this command, the function calls the corresponding
877 * command handler which performs argument checking and further processing.
879 * To cope with DOS attacks, a timer is set up right after the fork. If the
880 * connection was still not authenticated when the timeout expires, the child
881 * process is terminated.
885 * \sa alarm(2), \ref openssl.c, \ref crypt.h.
887 int handle_connect(int fd)
890 unsigned char rand_buf[APC_CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
891 unsigned char challenge_hash[HASH2_SIZE];
892 char *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
894 struct command_context cc_struct = {.u = NULL}, *cc = &cc_struct;
896 struct connection_features cf;
900 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
901 ret = mark_fd_blocking(fd);
904 /* send Welcome message */
905 ret = write_va_buffer(fd, "This is para_server, version "
906 PACKAGE_VERSION ".\n"
907 "Features: sha256\n" /* no longer announce this after 0.8.0 */
911 /* recv auth request line */
912 ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
915 ret = parse_auth_request(buf, ret, &cc->u, &cf);
919 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
920 ret = apc_pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
921 (unsigned char *)buf);
927 * We don't want to reveal our user names, so we send a
928 * challenge to the client even if the user does not exist, and
929 * fail the authentication later.
932 get_random_bytes_or_die((unsigned char *)buf, numbytes);
934 PARA_DEBUG_LOG("sending %d byte challenge + session key (%zu bytes)\n",
935 APC_CHALLENGE_SIZE, numbytes);
936 ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
940 ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
941 HANDSHAKE_BUFSIZE, &iov);
945 numbytes = iov.iov_len;
946 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
951 * The correct response is the hash of the first APC_CHALLENGE_SIZE bytes
952 * of the random data.
955 if (cf.sha256_requested) {
956 if (numbytes != HASH2_SIZE)
958 hash2_function((char *)rand_buf, APC_CHALLENGE_SIZE, challenge_hash);
959 if (memcmp(challenge_hash, buf, HASH2_SIZE))
961 } else { /* old client. This can be removed after 0.7.0 */
962 if (numbytes != HASH_SIZE)
964 hash_function((char *)rand_buf, APC_CHALLENGE_SIZE, challenge_hash);
965 if (memcmp(challenge_hash, buf, HASH_SIZE))
968 /* auth successful */
970 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
971 /* init stream cipher keys with the second part of the random buffer */
972 cc->scc.recv = sc_new(rand_buf + APC_CHALLENGE_SIZE, SESSION_KEY_LEN);
973 cc->scc.send = sc_new(rand_buf + APC_CHALLENGE_SIZE + SESSION_KEY_LEN,
975 ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
978 ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
981 ret = run_command(cc, &iov);
988 if (send_strerror(cc, -ret) >= 0)
989 send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
991 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
995 mutex_lock(mmd_mutex);
996 mmd->active_connections--;
997 mutex_unlock(mmd_mutex);
999 ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
1001 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
1003 sc_free(cc->scc.recv);
1004 sc_free(cc->scc.send);