command.c

   1 /*
   2  * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file command.c does client authentication and executes server commands */
   8
   9 #include <sys/time.h> /* gettimeofday */
  10 #include "server.cmdline.h"
  11 #include "afs_common.h"
  12 #include "server.h"
  13 #include "vss.h"
  14 #include "send.h"
  15 #include "rc4.h"
  16 #include <openssl/rc4.h>
  17 #include "error.h"
  18 #include "net.h"
  19 #include "daemon.h"
  20 #include "string.h"
  21 #include "fd.h"
  22 #include "user_list.h"
  23 #include "server_command_list.h"
  24
  25 /** commands including options must be shorter than this */
  26 #define MAX_COMMAND_LEN 4096
  27
  28 static RC4_KEY rc4_recv_key;
  29 static RC4_KEY rc4_send_key;
  30 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
  31
  32 extern const char *status_item_list[NUM_STAT_ITEMS];
  33 extern struct misc_meta_data *mmd;
  34 extern struct audio_file_selector selectors[];
  35 extern struct sender senders[];
  36
  37 static void dummy(__a_unused int s)
  38 {}
  39
  40 static void mmd_dup(struct misc_meta_data *new_mmd)
  41 {
  42         mmd_lock();
  43         *new_mmd = *mmd;
  44         mmd_unlock();
  45 }
  46
  47 /*
  48  * compute human readable string containing
  49  * vss status for given integer value
  50  */
  51 static char *vss_status_tohuman(unsigned int flags)
  52 {
  53         if (flags & VSS_PLAYING)
  54                 return para_strdup("playing");
  55         else if (flags & VSS_NEXT)
  56                 return para_strdup("stopped");
  57         else
  58                 return para_strdup("paused");
  59 }
  60
  61 /*
  62  * return human readable permission string. Never returns NULL.
  63  */
  64 static char *cmd_perms_itohuman(unsigned int perms)
  65 {
  66         char *msg = para_malloc(5 * sizeof(char));
  67
  68         msg[0] = perms & AFS_READ? 'a' : '-';
  69         msg[1] = perms & AFS_WRITE? 'A' : '-';
  70         msg[2] = perms & VSS_READ? 'v' : '-';
  71         msg[3] = perms & VSS_WRITE? 'V' : '-';
  72         msg[4] = '\0';
  73         return msg;
  74 }
  75
  76 /*
  77  * Never returns NULL.
  78  */
  79 static char *vss_get_status_flags(unsigned int flags)
  80 {
  81         char *msg = para_malloc(5 * sizeof(char));
  82
  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' : '_';
  87         msg[4] = '\0';
  88         return msg;
  89 }
  90
  91 /*
  92  * compute status bar string. Never returns NULL
  93  */
  94 static char *get_sb_string(struct misc_meta_data *nmmd)
  95 {
  96         char *base, *ret;
  97         long long unsigned secs = 0, rsecs = 0, percent = 0;
  98
  99         base = para_basename(nmmd->filename);
 100         if (!base)
 101                 return para_strdup("");
 102         if (!base[0])
 103                 return base;
 104         if (nmmd->afi.chunks_total) {
 105                 secs = (long long) nmmd->afi.seconds_total * nmmd->chunks_sent
 106                         / nmmd->afi.chunks_total;
 107                 rsecs = (long long) nmmd->afi.seconds_total *
 108                         (nmmd->afi.chunks_total - nmmd->chunks_sent)
 109                         / nmmd->afi.chunks_total;
 110                 percent = 100 * ((nmmd->chunks_sent + 5) / 10)
 111                         / ((nmmd->afi.chunks_total + 5) / 10);
 112         }
 113         ret = make_message("%llu:%02llu [%llu:%02llu] (%llu%%) %s",
 114                 secs / 60, secs % 60,
 115                 rsecs / 60, rsecs % 60,
 116                 percent,
 117                 base
 118         );
 119         free(base);
 120         return ret;
 121 }
 122
 123 static char *get_status(struct misc_meta_data *nmmd)
 124 {
 125         char *bar, *ret, mtime[30] = "";
 126         char *status, *flags; /* vss status info */
 127         char *ut = uptime_str();
 128         long offset = (nmmd->offset + 500) / 1000;
 129         struct timeval now;
 130         struct tm mtime_tm;
 131
 132         if (nmmd->audio_format >= 0) {
 133                 localtime_r(&nmmd->mtime, &mtime_tm);
 134                 strftime(mtime, 29, "%a %b %d %Y", &mtime_tm);
 135         }
 136         /* report real status */
 137         status = vss_status_tohuman(nmmd->vss_status_flags);
 138         flags = vss_get_status_flags(nmmd->vss_status_flags);
 139         bar = para_basename(nmmd->filename);
 140         gettimeofday(&now, NULL);
 141         ret = make_message(
 142                 "%s:%zu\n"      "%s:%s\n"               "%s:%lu\n"      "%s:%u\n"
 143                 "%s:%s\n"       "%s:%s\n"       "%s:%s\n"       "%s:%s\n"
 144                 "%s:%li\n"      "%s:%s\n"       "%s"            "%s"
 145                 "%s:%s\n"       "%s:%lu.%lu\n"  "%s:%lu.%lu\n",
 146                 status_item_list[SI_FILE_SIZE], nmmd->size / 1024,
 147                 status_item_list[SI_MTIME], mtime,
 148                 status_item_list[SI_LENGTH], nmmd->afi.seconds_total,
 149                 status_item_list[SI_NUM_PLAYED], nmmd->num_played,
 150
 151                 status_item_list[SI_STATUS_BAR], bar ? bar : "(none)",
 152                 status_item_list[SI_STATUS], status,
 153                 status_item_list[SI_STATUS_FLAGS], flags,
 154                 status_item_list[SI_SELECTOR], selectors[nmmd->selector_num].name,
 155
 156                 status_item_list[SI_OFFSET], offset,
 157                 status_item_list[SI_FORMAT], audio_format_name(nmmd->audio_format),
 158                 nmmd->selector_info,
 159                 nmmd->afi.info_string,
 160
 161                 status_item_list[SI_UPTIME], ut,
 162                 status_item_list[SI_STREAM_START],
 163                         (long unsigned)nmmd->stream_start.tv_sec,
 164                         (long unsigned)nmmd->stream_start.tv_usec,
 165                 status_item_list[SI_CURRENT_TIME],
 166                         (long unsigned)now.tv_sec,
 167                         (long unsigned)now.tv_usec
 168
 169         );
 170         free(bar);
 171         free(flags);
 172         free(status);
 173         free(ut);
 174         return ret;
 175 }
 176
 177 static int check_sender_args(int argc, char **argv, struct sender_command_data *scd)
 178 {
 179         int i;
 180         /* this has to match sender.h */
 181         const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
 182
 183         scd->sender_num = -1;
 184         if (argc < 2)
 185                 return -E_COMMAND_SYNTAX;
 186         for (i = 0; senders[i].name; i++)
 187                 if (!strcmp(senders[i].name, argv[1]))
 188                         break;
 189         PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
 190         if (!senders[i].name)
 191                 return -E_COMMAND_SYNTAX;
 192         scd->sender_num = i;
 193         for (i = 0; subcmds[i]; i++)
 194                 if (!strcmp(subcmds[i], argv[2]))
 195                         break;
 196         if (!subcmds[i])
 197                 return -E_COMMAND_SYNTAX;
 198         scd->cmd_num = i;
 199         mmd_lock();
 200         if (!senders[scd->sender_num].client_cmds[scd->cmd_num]) {
 201                 mmd_unlock();
 202                 return -E_SENDER_CMD;
 203         }
 204         mmd_unlock();
 205         switch (scd->cmd_num) {
 206         case SENDER_ON:
 207         case SENDER_OFF:
 208                 if (argc != 3)
 209                         return -E_COMMAND_SYNTAX;
 210                 break;
 211         case SENDER_DENY:
 212         case SENDER_ALLOW:
 213                 if (argc != 4 && argc != 5)
 214                         return -E_COMMAND_SYNTAX;
 215                 if (!inet_aton(argv[3], &scd->addr))
 216                         return -E_COMMAND_SYNTAX;
 217                 scd->netmask = 32;
 218                 if (argc == 5) {
 219                         scd->netmask = atoi(argv[4]);
 220                         if (scd->netmask < 0 || scd->netmask > 32)
 221                                 return -E_COMMAND_SYNTAX;
 222                 }
 223                 break;
 224         case SENDER_ADD:
 225         case SENDER_DELETE:
 226                 if (argc != 4 && argc != 5)
 227                         return -E_COMMAND_SYNTAX;
 228                 if (!inet_aton(argv[3], &scd->addr))
 229                         return -E_COMMAND_SYNTAX;
 230                 scd->port = -1;
 231                 if (argc == 5) {
 232                         scd->port = atoi(argv[4]);
 233                         if (scd->port < 0 || scd->port > 65535)
 234                                 return -E_COMMAND_SYNTAX;
 235                 }
 236                 break;
 237         default:
 238                 return -E_COMMAND_SYNTAX;
 239         }
 240         return 1;
 241 }
 242
 243 int com_sender(int fd, int argc, char **argv)
 244 {
 245         int i, ret;
 246         struct sender_command_data scd;
 247
 248         if (argc < 2) {
 249                 char *msg = NULL;
 250                 for (i = 0; senders[i].name; i++) {
 251                         char *tmp = make_message("%s%s\n",
 252                                 msg? msg : "", senders[i].name);
 253                         free(msg);
 254                         msg = tmp;
 255                 }
 256                 ret = send_buffer(fd, msg);
 257                 free(msg);
 258                 return ret;
 259         }
 260         ret = check_sender_args(argc, argv, &scd);
 261         if (ret < 0) {
 262                 char *msg;
 263                 if (scd.sender_num < 0)
 264                         return ret;
 265                 msg = senders[scd.sender_num].help();
 266                 send_buffer(fd, msg);
 267                 free(msg);
 268                 return 1;
 269         }
 270         for (i = 0; i < 10; i++) {
 271                 mmd_lock();
 272                 if (mmd->sender_cmd_data.cmd_num >= 0) {
 273                         mmd_unlock();
 274                         usleep(100 * 1000);
 275                         continue;
 276                 }
 277                 mmd->sender_cmd_data = scd;
 278                 mmd_unlock();
 279                 break;
 280         }
 281         return (i < 10)? 1 : -E_LOCK;
 282 }
 283
 284 /* server info */
 285 int com_si(int fd, int argc, __a_unused char **argv)
 286 {
 287         int i, ret;
 288         char *ut;
 289         char *selector_string = NULL, *sender_info = NULL, *sender_list = NULL;
 290
 291         if (argc != 1)
 292                 return -E_COMMAND_SYNTAX;
 293         mmd_lock();
 294         for (i = 0; selectors[i].name; i++) {
 295                 selector_string = para_strcat(selector_string, selectors[i].name);
 296                 selector_string = para_strcat(selector_string, " ");
 297         }
 298         for (i = 0; senders[i].name; i++) {
 299                 char *info = senders[i].info();
 300                 sender_info = para_strcat(sender_info, info);
 301                 free(info);
 302                 sender_list = para_strcat(sender_list, senders[i].name);
 303                 sender_list = para_strcat(sender_list, " ");
 304         }
 305         ut = uptime_str();
 306         ret = send_va_buffer(fd, "up: %s\nplayed: %u\n"
 307                 "pid: %d\n"
 308                 "connections (active/accepted/total): %u/%u/%u\n"
 309                 "current loglevel: %i\n"
 310                 "supported audio file selectors: %s\n"
 311                 "supported audio formats: %s\n"
 312                 "supported senders: %s\n"
 313                 "%s",
 314                 ut, mmd->num_played,
 315                 getppid(),
 316                 mmd->active_connections,
 317                 mmd->num_commands,
 318                 mmd->num_connects,
 319                 conf.loglevel_arg,
 320                 selector_string,
 321                 supported_audio_formats(),
 322                 sender_list,
 323                 sender_info
 324         );
 325         mmd_unlock();
 326         free(ut);
 327         free(selector_string);
 328         free(sender_list);
 329         free(sender_info);
 330         return ret;
 331 }
 332
 333 /* version */
 334 int com_version(int fd, int argc, __a_unused char **argv)
 335 {
 336         if (argc != 1)
 337                 return -E_COMMAND_SYNTAX;
 338         return send_buffer(fd, VERSION_TEXT("server")
 339                 "built: " BUILD_DATE "\n"
 340                 SYSTEM ", " CC_VERSION "\n"
 341         );
 342 }
 343
 344 /* sc */
 345 int com_sc(int fd, int argc, char **argv)
 346 {
 347         char *name = NULL;
 348         int ret, old = 0, count = -1; /* print af change forever */
 349
 350         if (argc > 1)
 351                 count = atoi(argv[1]);
 352 repeat:
 353         mmd_lock();
 354         if (old != mmd->num_played) {
 355                 old = mmd->num_played;
 356                 name = para_strdup(mmd->filename);
 357         }
 358         mmd_unlock();
 359         if (name) {
 360                 ret = send_va_buffer(fd, "%s\n", name);
 361                 free(name);
 362                 name = NULL;
 363                 if (ret < 0)
 364                         return ret;
 365                 if (argc > 1 && !--count)
 366                         return 1;
 367         }
 368         usleep(500000);
 369         goto repeat;
 370 }
 371
 372 /* sb */
 373 int com_sb(int fd, int argc, char **argv)
 374 {
 375         char *sb;
 376         int ret, nr = -1;       /* status bar will be printed that many
 377                                  * times. Negative value means: print
 378                                  * forever
 379                                  */
 380         if (argc > 1)
 381                 nr = atoi(argv[1]);
 382         while (nr) {
 383                 mmd_lock();
 384                 sb = get_sb_string(mmd);
 385                 mmd_unlock();
 386                 ret = send_va_buffer(fd, "%s\n", sb);
 387                 free(sb);
 388                 if (ret < 0)
 389                         return ret;
 390                 if (nr == 1)
 391                         return 1;
 392                 usleep(500000);
 393                 if (nr > 0)
 394                         nr--;
 395         }
 396         return 1;
 397 }
 398
 399 /* stat */
 400 int com_stat(int fd, int argc, char **argv)
 401 {
 402         int ret, num = 0;/* status will be printed that many
 403                           * times. num <= 0 means: print forever
 404                           */
 405         struct misc_meta_data tmp, *nmmd = &tmp;
 406         char *s;
 407
 408         signal(SIGUSR1, dummy);
 409
 410         if (argc > 1)
 411                 num = atoi(argv[1]);
 412         for (;;) {
 413
 414                 mmd_dup(nmmd);
 415                 s = get_status(nmmd);
 416                 ret = send_buffer(fd, s);
 417                 free(s);
 418                 if (ret < 0)
 419                         goto out;
 420                 ret = 1;
 421                 if (num == 1)
 422                         goto out;
 423                 sleep(50);
 424                 if (getppid() == 1)
 425                         return -E_SERVER_CRASH;
 426         }
 427 out:
 428         return ret;
 429 }
 430
 431 static int send_list_of_commands(int fd, struct server_command *cmd,
 432                 const char *handler)
 433 {
 434         int ret, i;
 435
 436         for (i = 1; cmd->name; cmd++, i++) {
 437                 char *perms = cmd_perms_itohuman(cmd->perms);
 438                 ret = send_va_buffer(fd, "%s\t%s\t%s\t%s\n", cmd->name,
 439                         handler,
 440                         perms,
 441                         cmd->description);
 442                 free(perms);
 443                 if (ret < 0)
 444                         return ret;
 445         }
 446         return 1;
 447 }
 448
 449 /* always returns string that must be freed by the caller in handler */
 450 static struct server_command *get_cmd_ptr(char *name, char **handler)
 451 {
 452         struct server_command *cmd;
 453
 454         for (cmd = server_cmds; cmd->name; cmd++)
 455                 if (!strcmp(cmd->name, name)) {
 456                         if (handler)
 457                                 *handler = para_strdup("para_server"); /* server commands */
 458                         return cmd;
 459                 }
 460         /* not found, look for commands supported by the current selector */
 461         mmd_lock();
 462         if (handler)
 463                 *handler = make_message("the %s selector",
 464                         selectors[mmd->selector_num].name);
 465         cmd = selectors[mmd->selector_num].cmd_list;
 466         mmd_unlock();
 467         for (; cmd->name; cmd++)
 468                 if (!strcmp(cmd->name, name))
 469                         return cmd;
 470         return NULL;
 471 }
 472
 473 /* help */
 474 int com_help(int fd, int argc, char **argv)
 475 {
 476         struct server_command *cmd;
 477         char *perms, *handler;
 478         int ret;
 479
 480         if (argc < 2) {
 481                 /* no argument given, print list of commands */
 482                 if ((ret = send_list_of_commands(fd, server_cmds, "server")) < 0)
 483                         return ret;
 484                 mmd_lock();
 485                 handler = para_strdup(selectors[mmd->selector_num].name);
 486                 cmd = selectors[mmd->selector_num].cmd_list;
 487                 mmd_unlock();
 488                 ret = send_list_of_commands(fd, cmd, handler);
 489                 free(handler);
 490                 return ret;
 491         }
 492         /* argument given for help */
 493         cmd = get_cmd_ptr(argv[1], &handler);
 494         if (!cmd) {
 495                 free(handler);
 496                 return -E_BAD_CMD;
 497         }
 498         perms = cmd_perms_itohuman(cmd->perms);
 499         ret = send_va_buffer(fd,
 500                 "%s - %s\n\n"
 501                 "handler: %s\n"
 502                 "permissions: %s\n"
 503                 "usage: %s\n\n"
 504                 "%s\n",
 505                 argv[1],
 506                 cmd->description,
 507                 handler,
 508                 perms,
 509                 cmd->usage,
 510                 cmd->help
 511         );
 512         free(perms);
 513         free(handler);
 514         return ret;
 515 }
 516
 517 /* hup */
 518 int com_hup(__a_unused int fd, int argc, __a_unused char **argv)
 519 {
 520         if (argc != 1)
 521                 return -E_COMMAND_SYNTAX;
 522         kill(getppid(), SIGHUP);
 523         return 1;
 524 }
 525
 526 /* term */
 527 int com_term(__a_unused int fd, int argc, __a_unused char **argv)
 528 {
 529         if (argc != 1)
 530                 return -E_COMMAND_SYNTAX;
 531         kill(getppid(), SIGTERM);
 532         return 1;
 533 }
 534
 535 int com_play(__a_unused int fd, int argc, __a_unused char **argv)
 536 {
 537         if (argc != 1)
 538                 return -E_COMMAND_SYNTAX;
 539         mmd_lock();
 540         mmd->new_vss_status_flags |= VSS_PLAYING;
 541         mmd->new_vss_status_flags &= ~VSS_NOMORE;
 542         mmd_unlock();
 543         return 1;
 544
 545 }
 546
 547 /* stop */
 548 int com_stop(__a_unused int fd, int argc, __a_unused char **argv)
 549 {
 550         if (argc != 1)
 551                 return -E_COMMAND_SYNTAX;
 552         mmd_lock();
 553         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 554         mmd->new_vss_status_flags &= ~VSS_REPOS;
 555         mmd->new_vss_status_flags |= VSS_NEXT;
 556         mmd_unlock();
 557         return 1;
 558 }
 559
 560 /* pause */
 561 int com_pause(__a_unused int fd, int argc, __a_unused char **argv)
 562 {
 563         if (argc != 1)
 564                 return -E_COMMAND_SYNTAX;
 565         mmd_lock();
 566         if (!vss_paused())
 567                 mmd->events++;
 568         mmd->new_vss_status_flags &= ~VSS_PLAYING;
 569         mmd->new_vss_status_flags &= ~VSS_NEXT;
 570         mmd_unlock();
 571         return 1;
 572 }
 573
 574 int com_chs(int fd, int argc, char **argv)
 575 {
 576         int i, ret;
 577
 578         if (argc == 1) {
 579                 char *selector;
 580                 mmd_lock();
 581                 selector = para_strdup(selectors[mmd->selector_num].name);
 582                 mmd_unlock();
 583                 ret = send_va_buffer(fd, "%s\n", selector);
 584                 free(selector);
 585                 return ret;
 586         }
 587         for (i = 0; selectors[i].name; i++) {
 588                 if (strcmp(selectors[i].name, argv[1]))
 589                         continue;
 590                 mmd_lock();
 591                 mmd->selector_change = i;
 592                 mmd->events++;
 593                 mmd_unlock();
 594                 return 1;
 595         }
 596         return -E_BAD_SELECTOR;
 597 }
 598
 599 /* next */
 600 int com_next(__a_unused int fd, int argc, __a_unused char **argv)
 601 {
 602         if (argc != 1)
 603                 return -E_COMMAND_SYNTAX;
 604         mmd_lock();
 605         mmd->events++;
 606         mmd->new_vss_status_flags |= VSS_NEXT;
 607         mmd_unlock();
 608         return 1;
 609 }
 610
 611 /* nomore */
 612 int com_nomore(__a_unused int fd, int argc, __a_unused char **argv)
 613 {
 614         if (argc != 1)
 615                 return -E_COMMAND_SYNTAX;
 616         mmd_lock();
 617         if (vss_playing() || vss_paused())
 618                 mmd->new_vss_status_flags |= VSS_NOMORE;
 619         mmd_unlock();
 620         return 1;
 621 }
 622
 623 /* ff */
 624 int com_ff(__a_unused int fd, int argc, char **argv)
 625 {
 626         long promille;
 627         int ret, backwards = 0;
 628         unsigned i;
 629         char c;
 630
 631         if (argc != 2)
 632                 return -E_COMMAND_SYNTAX;
 633         if (!(ret = sscanf(argv[1], "%u%c", &i, &c)))
 634                 return -E_COMMAND_SYNTAX;
 635         if (ret > 1 && c == '-')
 636                 backwards = 1; /* jmp backwards */
 637         mmd_lock();
 638         ret = -E_NO_AUDIO_FILE;
 639         if (!mmd->afi.chunks_total || !mmd->afi.seconds_total)
 640                 goto out;
 641         promille = (1000 * mmd->current_chunk) / mmd->afi.chunks_total;
 642         if (backwards)
 643                 promille -= 1000 * i / mmd->afi.seconds_total;
 644         else
 645                 promille += 1000 * i / mmd->afi.seconds_total;
 646         if (promille < 0)
 647                 promille = 0;
 648         if (promille >  1000) {
 649                 mmd->new_vss_status_flags |= VSS_NEXT;
 650                 goto out;
 651         }
 652         mmd->repos_request = (mmd->afi.chunks_total * promille) / 1000;
 653         mmd->new_vss_status_flags |= VSS_REPOS;
 654         mmd->new_vss_status_flags &= ~VSS_NEXT;
 655         mmd->events++;
 656         ret = 1;
 657 out:
 658         mmd_unlock();
 659         return ret;
 660 }
 661
 662 /* jmp */
 663 int com_jmp(__a_unused int fd, int argc, char **argv)
 664 {
 665         long unsigned int i;
 666         int ret;
 667
 668         if (argc != 2)
 669                 return -E_COMMAND_SYNTAX;
 670         if (sscanf(argv[1], "%lu", &i) <= 0)
 671                 return -E_COMMAND_SYNTAX;
 672         mmd_lock();
 673         ret = -E_NO_AUDIO_FILE;
 674         if (!mmd->afi.chunks_total)
 675                 goto out;
 676         if (i > 100)
 677                 i = 100;
 678         PARA_INFO_LOG("jumping to %lu%%\n", i);
 679         mmd->repos_request = (mmd->afi.chunks_total * i + 50)/ 100;
 680         PARA_INFO_LOG("sent: %lu,  offset before jmp: %lu\n",
 681                 mmd->chunks_sent, mmd->offset);
 682         mmd->new_vss_status_flags |= VSS_REPOS;
 683         mmd->new_vss_status_flags &= ~VSS_NEXT;
 684         ret = 1;
 685         mmd->events++;
 686 out:
 687         mmd_unlock();
 688         return ret;
 689 }
 690
 691 /*
 692  * check if perms are sufficient to exec a command having perms cmd_perms.
 693  * Returns 0 if perms are sufficient, -E_PERM otherwise.
 694  */
 695 static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
 696 {
 697         PARA_DEBUG_LOG("%s", "checking permissions\n");
 698         return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
 699 }
 700
 701 /*
 702  * Parse first string from *cmd and lookup in table of valid commands.
 703  * On error, NULL is returned.
 704  */
 705 static struct server_command *parse_cmd(const char *cmdstr)
 706 {
 707         char buf[255];
 708         int n = 0;
 709
 710         sscanf(cmdstr, "%200s%n", buf, &n);
 711         if (!n)
 712                 return NULL;
 713         buf[n] = '\0';
 714         return get_cmd_ptr(buf, NULL);
 715 }
 716
 717 static long int para_rand(long unsigned max)
 718 {
 719         return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
 720 }
 721
 722 static void init_rc4_keys(void)
 723 {
 724         int i;
 725
 726         for (i = 0; i < 2 * RC4_KEY_LEN; i++)
 727                 rc4_buf[i] = para_rand(256);
 728         PARA_DEBUG_LOG("rc4 keys initialized (%u:%u)\n",
 729                 (unsigned char) rc4_buf[0],
 730                 (unsigned char) rc4_buf[RC4_KEY_LEN]);
 731         RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf);
 732         RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 733 }
 734
 735 static void rc4_recv(unsigned long len, const unsigned char *indata,
 736                 unsigned char *outdata, __a_unused void *private_data)
 737 {
 738         RC4(&rc4_recv_key, len, indata, outdata);
 739 }
 740
 741 static void rc4_send(unsigned long len, const unsigned char *indata,
 742                 unsigned char *outdata, __a_unused void *private_data)
 743 {
 744         RC4(&rc4_send_key, len, indata, outdata);
 745 }
 746
 747 static int read_command(int fd, char **result)
 748 {
 749         int ret;
 750         char buf[4096];
 751         char *command = NULL;
 752
 753         for (;;) {
 754                 size_t numbytes;
 755                 char *p;
 756
 757                 ret = recv_buffer(fd, buf, sizeof(buf));
 758                 if (ret < 0)
 759                         goto out;
 760                 if (!ret)
 761                         break;
 762                 numbytes = ret;
 763                 ret = -E_COMMAND_SYNTAX;
 764                 if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
 765                         goto out;
 766                 command = para_strcat(command, buf);
 767                 p = strstr(command, EOC_MSG);
 768                 if (p) {
 769                         *p = '\0';
 770                         break;
 771                 }
 772         }
 773         ret = command? 1 : -E_COMMAND_SYNTAX;
 774 out:
 775         if (ret < 0)
 776                 free(command);
 777         else
 778                 *result = command;
 779         return ret;
 780
 781 }
 782
 783 /**
 784  * perform user authentication and execute a command
 785  *
 786  * \param fd the file descriptor to send output to
 787  * \param addr socket address info of peer
 788  *
 789  * \return EXIT_SUCCESS or EXIT_FAILURE
 790  *
 791  * Whenever para_server accepts an incoming tcp connection on
 792  * the port it listens on, it forks and the resulting child
 793  * calls this function.
 794  *
 795  * An RSA-based challenge/response is used to authenticate
 796  * the peer. It that authentication succeeds, a random RC4
 797  * session key is generated and sent back to the peer,
 798  * encrypted with its RSA public key.  From this point on,
 799  * all transfers are crypted with this session key.
 800  *
 801  * Next it is checked if the peer supplied  a valid server
 802  * command or a command for the audio file selector currently
 803  * in use.  If yes, and if the user has sufficient
 804  * permissions to execute that command, the function calls
 805  * the corresponding command handler which does argument
 806  * checking and further processing.
 807  *
 808  * In order to cope with a DOS attacks, a timeout is set up
 809  * which terminates the function if the connection was not
 810  * authenticated when the timeout expires.
 811  *
 812  * \sa alarm(2), rc4(3), crypt.c, crypt.h
 813  */
 814 int handle_connect(int fd, struct sockaddr_in *addr)
 815 {
 816         int ret, argc, use_rc4 = 0;
 817         char buf[4096];
 818         unsigned char crypt_buf[MAXLINE];
 819         struct user *u;
 820         struct server_command *cmd = NULL;
 821         long unsigned challenge_nr, chall_response;
 822         char **argv = NULL;
 823         char *p, *command = NULL;
 824         size_t numbytes;
 825
 826         signal(SIGCHLD, SIG_IGN);
 827         signal(SIGINT, SIG_DFL);
 828         signal(SIGTERM, SIG_DFL);
 829         signal(SIGHUP, SIG_DFL);
 830         signal(SIGUSR1, SIG_IGN);
 831
 832         challenge_nr = random();
 833         /* send Welcome message */
 834         ret = send_va_buffer(fd, "This is para_server, version "
 835                 PACKAGE_VERSION  ".\n" );
 836         if (ret < 0)
 837                 goto err_out;
 838         /* recv auth request line */
 839         ret = recv_buffer(fd, buf, sizeof(buf));
 840         if (ret < 0)
 841                 goto err_out;
 842         if (ret <= 6) {
 843                 ret = -E_AUTH;
 844                 goto err_out;
 845         }
 846         numbytes = ret;
 847         ret = -E_AUTH;
 848         if (strncmp(buf, "auth ", 5))
 849                 goto err_out;
 850
 851         if (numbytes < 9 || strncmp(buf, "auth rc4 ", 9))
 852                 p = buf + 5; /* client version < 0.2.6 */
 853         else {
 854                 p = buf + 9; /* client version >= 0.2.6 */
 855                 use_rc4 = 1;
 856         }
 857         PARA_DEBUG_LOG("received %s request for user %s\n",
 858                 use_rc4? "rc4" : "auth", p);
 859         ret = -E_BAD_USER;
 860         u = lookup_user(p);
 861         if (!u)
 862                 goto err_out;
 863         ret = para_encrypt_challenge(u->rsa, challenge_nr, crypt_buf);
 864         if (ret <= 0)
 865                 goto err_out;
 866         numbytes = ret;
 867         PARA_DEBUG_LOG("sending %zu byte challenge\n", numbytes);
 868         /* We can't use send_buffer here since buf may contain null bytes */
 869         ret = send_bin_buffer(fd,(char *) crypt_buf, numbytes);
 870         if (ret < 0)
 871                 goto err_out;
 872         /* recv decrypted number */
 873         ret = recv_buffer(fd, buf, sizeof(buf));
 874         if (ret < 0)
 875                 goto err_out;
 876         numbytes = ret;
 877         ret = -E_AUTH;
 878         if (!numbytes)
 879                 goto err_out;
 880         if (sscanf(buf, CHALLENGE_RESPONSE_MSG "%lu", &chall_response) < 1
 881                         || chall_response != challenge_nr)
 882                 goto err_out;
 883         /* auth successful, send 'Proceed' message */
 884         PARA_INFO_LOG("good auth for %s (%lu)\n", u->name, challenge_nr);
 885         sprintf(buf, "%s", PROCEED_MSG);
 886         if (use_rc4) {
 887                 init_rc4_keys();
 888                 ret = para_encrypt_buffer(u->rsa, rc4_buf, 2 * RC4_KEY_LEN,
 889                         (unsigned char *)buf + PROCEED_MSG_LEN + 1);
 890                 if (ret <= 0)
 891                         goto err_out;
 892                 numbytes = ret + strlen(PROCEED_MSG) + 1;
 893         } else
 894                 numbytes = strlen(buf);
 895         ret = send_bin_buffer(fd, buf, numbytes);
 896         if (ret < 0)
 897                 goto err_out;
 898         if (use_rc4)
 899                 enable_crypt(fd, rc4_recv, rc4_send, NULL);
 900         ret = read_command(fd, &command);
 901         if (ret < 0)
 902                 goto err_out;
 903         ret = -E_BAD_CMD;
 904         cmd = parse_cmd(command);
 905         if (!cmd)
 906                 goto err_out;
 907         /* valid command, check permissions */
 908         ret = check_perms(u->perms, cmd);
 909         if (ret < 0)
 910                 goto err_out;
 911         /* valid command and sufficient perms */
 912         alarm(0);
 913         argc = split_args(command, &argv, "\n");
 914         mmd_lock();
 915         mmd->num_commands++;
 916         mmd_unlock();
 917         PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cmd->name, u->name,
 918                 inet_ntoa(addr->sin_addr));
 919         ret = cmd->handler(fd, argc, argv);
 920         if (ret >= 0) {
 921                 ret = EXIT_SUCCESS;
 922                 goto out;
 923         }
 924 err_out:
 925         PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
 926         if (ret != -E_SEND && ret != -E_RECV)
 927                 send_va_buffer(fd, "%s\n", PARA_STRERROR(-ret));
 928         ret = EXIT_FAILURE;
 929 out:
 930         free(command);
 931         free(argv);
 932         mmd_lock();
 933         if (cmd && (cmd->perms & AFS_WRITE) && ret >= 0)
 934                 mmd->events++;
 935         mmd->active_connections--;
 936         mmd_unlock();
 937         return ret;
 938 }