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>
11 #include <arpa/inet.h>
16 #include "server.lsg.h"
34 #include "server_cmd.lsg.h"
35 #include "user_list.h"
39 #define SERVER_CMD_AUX_INFO(_arg) _arg,
40 static const unsigned server_command_perms[] = {LSG_SERVER_CMD_AUX_INFOS};
41 #undef SERVER_CMD_AUX_INFO
42 #define SERVER_CMD_AUX_INFO(_arg) #_arg,
43 static const char * const server_command_perms_txt[] = {LSG_SERVER_CMD_AUX_INFOS};
44 #undef SERVER_CMD_AUX_INFO
46 /** Commands including options must be shorter than this. */
47 #define MAX_COMMAND_LEN 32768
50 extern struct misc_meta_data *mmd;
51 extern struct sender senders[];
52 int send_afs_status(struct command_context *cc, int parser_friendly);
54 static void dummy(__a_unused int s)
59 * Compute human readable vss status text.
61 * We can't call vss_playing() and friends here because those functions read
62 * the flags from the primary mmd structure, so calling them from command
63 * handler context would require to take the mmd lock. At the time the function
64 * is called we already took a copy of the mmd structure and want to use the
65 * flags value of the copy for computing the vss status text.
67 static char *vss_status_tohuman(unsigned int flags)
69 if (flags & VSS_PLAYING)
70 return para_strdup("playing");
72 return para_strdup("stopped");
73 return para_strdup("paused");
79 static char *vss_get_status_flags(unsigned int flags)
81 char *msg = para_malloc(5 * sizeof(char));
83 msg[0] = (flags & VSS_PLAYING)? 'P' : '_';
84 msg[1] = (flags & VSS_NOMORE)? 'O' : '_';
85 msg[2] = (flags & VSS_NEXT)? 'N' : '_';
86 msg[3] = (flags & VSS_REPOS)? 'R' : '_';
91 static unsigned get_status(struct misc_meta_data *nmmd, bool parser_friendly,
94 char *status, *flags; /* vss status info */
95 /* nobody updates our version of "now" */
96 long offset = (nmmd->offset + 500) / 1000;
97 struct timeval current_time;
98 struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
100 /* report real status */
101 status = vss_status_tohuman(nmmd->vss_status_flags);
102 flags = vss_get_status_flags(nmmd->vss_status_flags);
103 clock_get_realtime(¤t_time);
105 * The calls to WRITE_STATUS_ITEM() below never fail because
106 * b->max_size is zero (unlimited), see \ref para_printf(). However,
107 * clang is not smart enough to prove this and complains nevertheless.
108 * Casting the return value to void silences clang.
110 (void)WRITE_STATUS_ITEM(&b, SI_status, "%s\n", status);
111 (void)WRITE_STATUS_ITEM(&b, SI_status_flags, "%s\n", flags);
112 (void)WRITE_STATUS_ITEM(&b, SI_offset, "%li\n", offset);
113 (void)WRITE_STATUS_ITEM(&b, SI_afs_mode, "%s\n", mmd->afs_mode_string);
114 (void)WRITE_STATUS_ITEM(&b, SI_stream_start, "%lu.%lu\n",
115 (long unsigned)nmmd->stream_start.tv_sec,
116 (long unsigned)nmmd->stream_start.tv_usec);
117 (void)WRITE_STATUS_ITEM(&b, SI_current_time, "%lu.%lu\n",
118 (long unsigned)current_time.tv_sec,
119 (long unsigned)current_time.tv_usec);
127 * Send a sideband packet through a blocking file descriptor.
129 * \param scc fd and crypto keys.
130 * \param buf The buffer to send.
131 * \param numbytes The size of \a buf.
132 * \param band The sideband designator of this packet.
133 * \param dont_free If true, never deallocate \a buf.
135 * The nonblock flag must be disabled for the file descriptor given by \a scc.
137 * Stream cipher encryption is automatically activated if necessary via the
138 * sideband transformation, depending on the value of \a band.
142 * \sa \ref send_sb_va().
144 int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
145 int band, bool dont_free)
148 struct sb_context *sbc;
150 sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
151 struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
153 sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
155 ret = sb_get_send_buffers(sbc, iov);
156 ret = xwritev(scc->fd, iov, ret);
159 } while (sb_sent(sbc, ret) == false);
167 * Create a variable sized buffer and send it as a sideband packet.
169 * \param scc Passed to \ref send_sb.
170 * \param band See \ref send_sb.
171 * \param fmt The format string.
173 * \return The return value of the underlying call to \ref send_sb.
175 __printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
176 const char *fmt, ...)
183 ret = xvasprintf(&msg, fmt, ap);
185 return send_sb(scc, msg, ret, band, false);
189 * Send an error message to a client.
191 * \param cc Client info.
192 * \param err The (positive) error code.
194 * \return The return value of the underlying call to send_sb_va().
196 int send_strerror(struct command_context *cc, int err)
198 return send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err));
202 * Send an error context to a client,
204 * \param cc Client info.
205 * \param errctx The error context string.
207 * \return The return value of the underlying call to send_sb_va().
209 * This function frees the error context string after it was sent.
211 int send_errctx(struct command_context *cc, char *errctx)
217 ret = send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", errctx);
222 static int check_sender_args(struct command_context *cc,
223 struct lls_parse_result *lpr, struct sender_command_data *scd)
226 const char * const subcmds[] = {SENDER_SUBCOMMANDS};
229 unsigned num_inputs = lls_num_inputs(lpr);
231 scd->sender_num = -1;
232 ret = lls(lls_check_arg_count(lpr, 2, INT_MAX, &errctx));
234 send_errctx(cc, errctx);
237 arg = lls_input(0, lpr);
238 for (i = 0; senders[i].name; i++)
239 if (!strcmp(senders[i].name, arg))
241 if (!senders[i].name)
242 return -E_COMMAND_SYNTAX;
244 arg = lls_input(1, lpr);
245 for (i = 0; i < NUM_SENDER_CMDS; i++)
246 if (!strcmp(subcmds[i], arg))
248 if (i == NUM_SENDER_CMDS)
249 return -E_COMMAND_SYNTAX;
251 if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
252 return -E_SENDER_CMD;
253 switch (scd->cmd_num) {
257 return -E_COMMAND_SYNTAX;
261 if (num_inputs != 3 || parse_cidr(lls_input(2, lpr), scd->host,
262 sizeof(scd->host), &scd->netmask) == NULL)
263 return -E_COMMAND_SYNTAX;
268 return -E_COMMAND_SYNTAX;
269 return parse_fec_url(lls_input(2, lpr), scd);
271 return -E_COMMAND_SYNTAX;
277 * Send a sideband packet through a blocking file descriptor.
279 * \param scc fd and crypto keys.
280 * \param expected_band The expected band designator.
281 * \param max_size Passed to \ref sb_new_recv().
282 * \param result Body of the sideband packet is returned here.
284 * If \a expected_band is not \p SBD_ANY, the band designator of the received
285 * sideband packet is compared to \a expected_band and a mismatch is considered
290 int recv_sb(struct stream_cipher_context *scc,
291 enum sb_designator expected_band,
292 size_t max_size, struct iovec *result)
295 struct sb_context *sbc;
297 struct sb_buffer sbb;
298 sb_transformation trafo;
300 trafo = expected_band != SBD_ANY && expected_band < SBD_PROCEED?
302 sbc = sb_new_recv(max_size, trafo, scc->recv);
304 sb_get_recv_buffer(sbc, &iov);
305 ret = recv_bin_buffer(scc->fd, iov.iov_base, iov.iov_len);
310 ret = sb_received(sbc, ret, &sbb);
317 if (expected_band != SBD_ANY && sbb.band != expected_band)
326 static int com_sender(struct command_context *cc, struct lls_parse_result *lpr)
330 struct sender_command_data scd;
332 if (lls_num_inputs(lpr) == 0) {
333 for (i = 0; senders[i].name; i++) {
335 ret = xasprintf(&tmp, "%s%s\n", msg? msg : "",
340 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
342 ret = check_sender_args(cc, lpr, &scd);
344 if (scd.sender_num < 0)
346 if (strcmp(lls_input(1, lpr), "status") == 0)
347 msg = senders[scd.sender_num].status();
349 msg = senders[scd.sender_num].help();
350 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
353 switch (scd.cmd_num) {
356 assert(senders[scd.sender_num].resolve_target);
357 ret = senders[scd.sender_num].resolve_target(lls_input(2, lpr),
363 for (i = 0; i < 10; i++) {
364 mutex_lock(mmd_mutex);
365 if (mmd->sender_cmd_data.cmd_num >= 0) {
366 /* another sender command is active, retry in 100ms */
367 struct timespec ts = {.tv_nsec = 100 * 1000 * 1000};
368 mutex_unlock(mmd_mutex);
369 nanosleep(&ts, NULL);
372 mmd->sender_cmd_data = scd;
373 mutex_unlock(mmd_mutex);
376 return (i < 10)? 1 : -E_LOCK;
378 EXPORT_SERVER_CMD_HANDLER(sender);
380 static int com_si(struct command_context *cc,
381 __a_unused struct lls_parse_result *lpr)
386 ut = daemon_get_uptime_str(now);
387 mutex_lock(mmd_mutex);
388 ret = xasprintf(&msg,
389 "up: %s\nplayed: %u\n"
392 "connections (active/accepted/total): %u/%u/%u\n"
393 "current loglevel: %s\n"
394 "supported audio formats: %s\n",
398 mmd->active_connections,
401 ENUM_STRING_VAL(LOGLEVEL),
402 AUDIO_FORMAT_HANDLERS
404 mutex_unlock(mmd_mutex);
406 return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
408 EXPORT_SERVER_CMD_HANDLER(si);
410 static int com_version(struct command_context *cc, struct lls_parse_result *lpr)
415 if (SERVER_CMD_OPT_GIVEN(VERSION, VERBOSE, lpr))
416 len = xasprintf(&msg, "%s", version_text("server"));
418 len = xasprintf(&msg, "%s\n", version_single_line("server"));
419 return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
421 EXPORT_SERVER_CMD_HANDLER(version);
423 /** These status items are cleared if no audio file is currently open. */
424 #define EMPTY_STATUS_ITEMS \
429 ITEM(attributes_bitmap) \
430 ITEM(attributes_txt) \
441 ITEM(seconds_total) \
454 ITEM(amplification) \
457 * Create a set of audio-file related status items with empty values. These are
458 * written to stat clients when no audio file is open.
460 static unsigned empty_status_items(bool parser_friendly, char **result)
466 len = xasprintf(&esi,
467 #define ITEM(x) "0004 %02x:\n"
470 #define ITEM(x) , (unsigned) SI_ ## x
475 len = xasprintf(&esi,
476 #define ITEM(x) "%s:\n"
479 #define ITEM(x) ,status_item_list[SI_ ## x]
486 #undef EMPTY_STATUS_ITEMS
488 static int com_stat(struct command_context *cc, struct lls_parse_result *lpr)
491 struct misc_meta_data tmp, *nmmd = &tmp;
493 bool parser_friendly = SERVER_CMD_OPT_GIVEN(STAT, PARSER_FRIENDLY,
495 uint32_t num = SERVER_CMD_UINT32_VAL(STAT, NUM, lpr);
497 para_sigaction(SIGUSR1, dummy);
500 * Copy the mmd structure to minimize the time we hold the mmd
503 mutex_lock(mmd_mutex);
505 mutex_unlock(mmd_mutex);
506 ret = get_status(nmmd, parser_friendly, &s);
507 ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
510 if (nmmd->vss_status_flags & VSS_NEXT) {
512 ret = empty_status_items(parser_friendly, &esi);
513 ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT, false);
517 send_afs_status(cc, parser_friendly);
519 if (num > 0 && !--num)
522 ret = -E_SERVER_CRASH;
529 EXPORT_SERVER_CMD_HANDLER(stat);
531 /* fixed-length, human readable permission string */
532 const char *server_cmd_perms_str(unsigned int perms)
534 static char result[5];
536 result[0] = perms & AFS_READ? 'a' : '-';
537 result[1] = perms & AFS_WRITE? 'A' : '-';
538 result[2] = perms & VSS_READ? 'v' : '-';
539 result[3] = perms & VSS_WRITE? 'V' : '-';
544 static int send_list_of_commands(struct command_context *cc)
547 const struct lls_command *cmd;
548 char *msg = para_strdup("");
550 for (i = 1; (cmd = lls_cmd(i, server_cmd_suite)); i++) {
551 const char *perms = server_cmd_perms_str(server_command_perms[i]);
552 char *tmp = make_message("%s%s\t%s\t%s\n", msg,
553 lls_command_name(cmd), perms, lls_purpose(cmd));
557 return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
560 static int com_help(struct command_context *cc, struct lls_parse_result *lpr)
563 char *long_help, *buf, *errctx;
565 const struct lls_command *cmd;
567 ret = lls(lls_check_arg_count(lpr, 0, 1, &errctx));
569 send_errctx(cc, errctx);
572 if (lls_num_inputs(lpr) == 0)
573 return send_list_of_commands(cc);
574 /* argument given for help */
575 ret = lls(lls_lookup_subcmd(lls_input(0, lpr), server_cmd_suite,
578 send_errctx(cc, errctx);
581 cmd = lls_cmd(ret, server_cmd_suite);
582 perms = server_command_perms_txt[ret];
583 long_help = lls_long_help(cmd);
585 ret = xasprintf(&buf, "%spermissions: %s\n", long_help, perms);
587 return send_sb(&cc->scc, buf, ret, SBD_OUTPUT, false);
589 EXPORT_SERVER_CMD_HANDLER(help);
591 static int com_hup(__a_unused struct command_context *cc,
592 __a_unused struct lls_parse_result *lpr)
594 kill(getppid(), SIGHUP);
597 EXPORT_SERVER_CMD_HANDLER(hup);
599 static int com_term(__a_unused struct command_context *cc,
600 __a_unused struct lls_parse_result *lpr)
602 kill(getppid(), SIGTERM);
605 EXPORT_SERVER_CMD_HANDLER(term);
607 static int com_play(__a_unused struct command_context *cc,
608 __a_unused struct lls_parse_result *lpr)
610 mutex_lock(mmd_mutex);
611 mmd->new_vss_status_flags |= VSS_PLAYING;
612 mmd->new_vss_status_flags &= ~VSS_NOMORE;
613 mutex_unlock(mmd_mutex);
616 EXPORT_SERVER_CMD_HANDLER(play);
618 static int com_stop(__a_unused struct command_context *cc,
619 __a_unused struct lls_parse_result *lpr)
621 mutex_lock(mmd_mutex);
622 mmd->new_vss_status_flags &= ~VSS_PLAYING;
623 mmd->new_vss_status_flags &= ~VSS_REPOS;
624 mmd->new_vss_status_flags |= VSS_NEXT;
625 mutex_unlock(mmd_mutex);
628 EXPORT_SERVER_CMD_HANDLER(stop);
630 static int com_pause(__a_unused struct command_context *cc,
631 __a_unused struct lls_parse_result *lpr)
633 mutex_lock(mmd_mutex);
634 if (!vss_paused() && !vss_stopped()) {
636 mmd->new_vss_status_flags &= ~VSS_PLAYING;
637 mmd->new_vss_status_flags &= ~VSS_NEXT;
639 mutex_unlock(mmd_mutex);
642 EXPORT_SERVER_CMD_HANDLER(pause);
644 static int com_next(__a_unused struct command_context *cc,
645 __a_unused struct lls_parse_result *lpr)
647 mutex_lock(mmd_mutex);
649 mmd->new_vss_status_flags |= VSS_NEXT;
650 mutex_unlock(mmd_mutex);
653 EXPORT_SERVER_CMD_HANDLER(next);
655 static int com_nomore(__a_unused struct command_context *cc,
656 __a_unused struct lls_parse_result *lpr)
658 mutex_lock(mmd_mutex);
659 if (vss_playing() || vss_paused())
660 mmd->new_vss_status_flags |= VSS_NOMORE;
661 mutex_unlock(mmd_mutex);
664 EXPORT_SERVER_CMD_HANDLER(nomore);
666 static int com_ff(struct command_context *cc, struct lls_parse_result *lpr)
669 int ret, backwards = 0;
673 ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
675 send_errctx(cc, errctx);
678 if (!(ret = sscanf(lls_input(0, lpr), "%u%c", &i, &c)))
679 return -E_COMMAND_SYNTAX;
680 if (ret > 1 && c == '-')
681 backwards = 1; /* jmp backwards */
682 mutex_lock(mmd_mutex);
683 ret = -E_NO_AUDIO_FILE;
684 if (!mmd->afd.afhi.chunks_total || !mmd->afd.afhi.seconds_total)
687 promille = (1000 * mmd->current_chunk) / mmd->afd.afhi.chunks_total;
689 promille -= 1000 * i / mmd->afd.afhi.seconds_total;
691 promille += 1000 * i / mmd->afd.afhi.seconds_total;
694 if (promille > 1000) {
695 mmd->new_vss_status_flags |= VSS_NEXT;
698 mmd->repos_request = (mmd->afd.afhi.chunks_total * promille) / 1000;
699 mmd->new_vss_status_flags |= VSS_REPOS;
700 mmd->new_vss_status_flags &= ~VSS_NEXT;
703 mutex_unlock(mmd_mutex);
706 EXPORT_SERVER_CMD_HANDLER(ff);
708 static int com_jmp(struct command_context *cc, struct lls_parse_result *lpr)
714 ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
716 send_errctx(cc, errctx);
719 if (sscanf(lls_input(0, lpr), "%lu", &i) <= 0)
720 return -ERRNO_TO_PARA_ERROR(EINVAL);
721 mutex_lock(mmd_mutex);
722 ret = -E_NO_AUDIO_FILE;
723 if (!mmd->afd.afhi.chunks_total)
727 PARA_INFO_LOG("jumping to %lu%%\n", i);
728 mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50) / 100;
729 PARA_INFO_LOG("sent: %lu, offset before jmp: %li\n",
730 mmd->chunks_sent, mmd->offset);
731 mmd->new_vss_status_flags |= VSS_REPOS;
732 mmd->new_vss_status_flags &= ~VSS_NEXT;
736 mutex_unlock(mmd_mutex);
739 EXPORT_SERVER_CMD_HANDLER(jmp);
741 /* deprecated, does nothing */
742 static int com_tasks(__a_unused struct command_context *cc,
743 __a_unused struct lls_parse_result *lpr)
747 EXPORT_SERVER_CMD_HANDLER(tasks);
749 static void reset_signals(void)
751 para_sigaction(SIGCHLD, SIG_IGN);
752 para_sigaction(SIGINT, SIG_DFL);
753 para_sigaction(SIGTERM, SIG_DFL);
754 para_sigaction(SIGHUP, SIG_DFL);
757 struct connection_features {
758 int dummy; /* none at the moment */
761 static int parse_auth_request(char *buf, int len, struct user **u,
762 struct connection_features *cf)
765 char *p, *username, **features = NULL;
766 size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
769 memset(cf, 0, sizeof(*cf));
770 if (len < auth_rq_len + 2)
771 return -E_AUTH_REQUEST;
772 if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
773 return -E_AUTH_REQUEST;
774 username = buf + auth_rq_len;
775 p = strchr(username, ' ');
779 return -E_AUTH_REQUEST;
782 create_argv(p, ",", &features);
783 for (i = 0; features[i]; i++) {
784 if (strcmp(features[i], "sideband") == 0)
786 if (strcmp(features[i], "aes_ctr128") == 0)
789 ret = -E_BAD_FEATURE;
794 PARA_DEBUG_LOG("received auth request for user %s\n", username);
795 *u = lookup_user(username);
802 #define HANDSHAKE_BUFSIZE 4096
804 static int run_command(struct command_context *cc, struct iovec *iov)
807 char *p, *end, **argv;
808 const struct lls_command *lcmd = NULL;
810 struct lls_parse_result *lpr;
813 if (iov->iov_base == NULL || iov->iov_len == 0)
814 return -ERRNO_TO_PARA_ERROR(EINVAL);
816 p[iov->iov_len - 1] = '\0'; /* just to be sure */
818 ret = lls(lls_lookup_subcmd(p, server_cmd_suite, &errctx));
820 send_errctx(cc, errctx);
823 perms = server_command_perms[ret];
824 if ((perms & cc->u->perms) != perms)
826 lcmd = lls_cmd(ret, server_cmd_suite);
827 end = iov->iov_base + iov->iov_len;
828 for (i = 0; p < end; i++)
831 argv = para_malloc((argc + 1) * sizeof(char *));
832 for (i = 0, p = iov->iov_base; p < end; i++) {
833 argv[i] = para_strdup(p);
837 PARA_NOTICE_LOG("calling com_%s() for user %s\n",
838 lls_command_name(lcmd), cc->u->name);
839 ret = lls(lls_parse(argc, argv, lcmd, &lpr, &errctx));
841 const struct server_cmd_user_data *ud = lls_user_data(lcmd);
842 ret = ud->handler(cc, lpr);
843 lls_free_parse_result(lpr, lcmd);
845 send_errctx(cc, errctx);
847 mutex_lock(mmd_mutex);
849 if (ret >= 0 && (perms & AFS_WRITE))
851 mutex_unlock(mmd_mutex);
856 * Perform user authentication and execute a command.
858 * \param fd The file descriptor to send output to.
860 * Whenever para_server accepts an incoming tcp connection on the port it
861 * listens on, it forks and the resulting child calls this function.
863 * An RSA-based challenge/response is used to authenticate the peer. It that
864 * authentication succeeds, a random session key is generated and sent back to
865 * the peer, encrypted with its RSA public key. From this point on, all
866 * transfers are crypted with this session key.
868 * Next it is checked if the peer supplied a valid server command or a command
869 * for the audio file selector. If yes, and if the user has sufficient
870 * permissions to execute that command, the function calls the corresponding
871 * command handler which does argument checking and further processing.
873 * In order to cope with DOS attacks, a timeout is set up which terminates
874 * the function if the connection was not authenticated when the timeout
877 * \sa alarm(2), \ref openssl.c, \ref crypt.h.
879 __noreturn void handle_connect(int fd)
882 unsigned char rand_buf[APC_CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
883 unsigned char challenge_hash[HASH_SIZE];
884 char *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
886 struct command_context cc_struct = {.u = NULL}, *cc = &cc_struct;
888 struct connection_features cf;
892 /* we need a blocking fd here as recv() might return EAGAIN otherwise. */
893 ret = mark_fd_blocking(fd);
896 /* send Welcome message */
897 ret = write_va_buffer(fd, "This is para_server, version "
898 PACKAGE_VERSION ".\n"
899 "Features: sideband,aes_ctr128\n"
903 /* recv auth request line */
904 ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
907 ret = parse_auth_request(buf, ret, &cc->u, &cf);
911 get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
912 ret = apc_pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
913 (unsigned char *)buf);
919 * We don't want to reveal our user names, so we send a
920 * challenge to the client even if the user does not exist, and
921 * fail the authentication later.
924 get_random_bytes_or_die((unsigned char *)buf, numbytes);
926 PARA_DEBUG_LOG("sending %d byte challenge + session key (%zu bytes)\n",
927 APC_CHALLENGE_SIZE, numbytes);
928 ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
932 ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
933 HANDSHAKE_BUFSIZE, &iov);
937 numbytes = iov.iov_len;
938 PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
943 * The correct response is the hash of the first APC_CHALLENGE_SIZE bytes
944 * of the random data.
947 if (numbytes != HASH_SIZE)
949 hash_function((char *)rand_buf, APC_CHALLENGE_SIZE, challenge_hash);
950 if (memcmp(challenge_hash, buf, HASH_SIZE))
952 /* auth successful */
954 PARA_INFO_LOG("good auth for %s\n", cc->u->name);
955 /* init stream cipher keys with the second part of the random buffer */
956 cc->scc.recv = sc_new(rand_buf + APC_CHALLENGE_SIZE, SESSION_KEY_LEN);
957 cc->scc.send = sc_new(rand_buf + APC_CHALLENGE_SIZE + SESSION_KEY_LEN,
959 ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
962 ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
965 ret = run_command(cc, &iov);
972 if (send_strerror(cc, -ret) >= 0)
973 send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
975 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
979 mutex_lock(mmd_mutex);
980 mmd->active_connections--;
981 mutex_unlock(mmd_mutex);
983 ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
985 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
987 sc_free(cc->scc.recv);
988 sc_free(cc->scc.send);
989 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);