release/src/router/tinc/src/invitation.c

   1 /*
   2     invitation.c -- Create and accept invitations
   3     Copyright (C) 2013-2014 Guus Sliepen <guus@tinc-vpn.org>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License along
  16     with this program; if not, write to the Free Software Foundation, Inc.,
  17     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "system.h"
  21
  22 #include "control_common.h"
  23 #include "crypto.h"
  24 #include "ecdsa.h"
  25 #include "ecdsagen.h"
  26 #include "invitation.h"
  27 #include "names.h"
  28 #include "netutl.h"
  29 #include "rsagen.h"
  30 #include "script.h"
  31 #include "sptps.h"
  32 #include "tincctl.h"
  33 #include "utils.h"
  34 #include "xalloc.h"
  35
  36 int addressfamily = AF_UNSPEC;
  37
  38 static void scan_for_hostname(const char *filename, char **hostname, char **port) {
  39         if(!filename || (*hostname && *port))
  40                 return;
  41
  42         FILE *f = fopen(filename, "r");
  43         if(!f)
  44                 return;
  45
  46         while(fgets(line, sizeof line, f)) {
  47                 if(!rstrip(line))
  48                         continue;
  49                 char *p = line, *q;
  50                 p += strcspn(p, "\t =");
  51                 if(!*p)
  52                         continue;
  53                 q = p + strspn(p, "\t ");
  54                 if(*q == '=')
  55                         q += 1 + strspn(q + 1, "\t ");
  56                 *p = 0;
  57                 p = q + strcspn(q, "\t ");
  58                 if(*p)
  59                         *p++ = 0;
  60                 p += strspn(p, "\t ");
  61                 p[strcspn(p, "\t ")] = 0;
  62
  63                 if(!*port && !strcasecmp(line, "Port")) {
  64                         *port = xstrdup(q);
  65                 } else if(!*hostname && !strcasecmp(line, "Address")) {
  66                         *hostname = xstrdup(q);
  67                         if(*p) {
  68                                 free(*port);
  69                                 *port = xstrdup(p);
  70                         }
  71                 }
  72
  73                 if(*hostname && *port)
  74                         break;
  75         }
  76
  77         fclose(f);
  78 }
  79
  80 char *get_my_hostname() {
  81         char *hostname = NULL;
  82         char *port = NULL;
  83         char *hostport = NULL;
  84         char *name = get_my_name(false);
  85         char *filename = NULL;
  86
  87         // Use first Address statement in own host config file
  88         if(check_id(name)) {
  89                 xasprintf(&filename, "%s" SLASH "hosts" SLASH "%s", confbase, name);
  90                 scan_for_hostname(filename, &hostname, &port);
  91                 scan_for_hostname(tinc_conf, &hostname, &port);
  92         }
  93
  94         if(hostname)
  95                 goto done;
  96
  97         // If that doesn't work, guess externally visible hostname
  98         fprintf(stderr, "Trying to discover externally visible hostname...\n");
  99         struct addrinfo *ai = str2addrinfo("tinc-vpn.org", "80", SOCK_STREAM);
 100         struct addrinfo *aip = ai;
 101         static const char request[] = "GET http://tinc-vpn.org/host.cgi HTTP/1.0\r\n\r\n";
 102
 103         while(aip) {
 104                 int s = socket(aip->ai_family, aip->ai_socktype, aip->ai_protocol);
 105                 if(s >= 0) {
 106                         if(connect(s, aip->ai_addr, aip->ai_addrlen)) {
 107                                 closesocket(s);
 108                                 s = -1;
 109                         }
 110                 }
 111                 if(s >= 0) {
 112                         send(s, request, sizeof request - 1, 0);
 113                         int len = recv(s, line, sizeof line - 1, MSG_WAITALL);
 114                         if(len > 0) {
 115                                 line[len] = 0;
 116                                 if(line[len - 1] == '\n')
 117                                         line[--len] = 0;
 118                                 char *p = strrchr(line, '\n');
 119                                 if(p && p[1])
 120                                         hostname = xstrdup(p + 1);
 121                         }
 122                         closesocket(s);
 123                         if(hostname)
 124                                 break;
 125                 }
 126                 aip = aip->ai_next;
 127                 continue;
 128         }
 129
 130         if(ai)
 131                 freeaddrinfo(ai);
 132
 133         // Check that the hostname is reasonable
 134         if(hostname) {
 135                 for(char *p = hostname; *p; p++) {
 136                         if(isalnum(*p) || *p == '-' || *p == '.' || *p == ':')
 137                                 continue;
 138                         // If not, forget it.
 139                         free(hostname);
 140                         hostname = NULL;
 141                         break;
 142                 }
 143         }
 144
 145         if(!tty) {
 146                 if(!hostname) {
 147                         fprintf(stderr, "Could not determine the external address or hostname. Please set Address manually.\n");
 148                         return NULL;
 149                 }
 150                 goto save;
 151         }
 152
 153 again:
 154         fprintf(stderr, "Please enter your host's external address or hostname");
 155         if(hostname)
 156                 fprintf(stderr, " [%s]", hostname);
 157         fprintf(stderr, ": ");
 158
 159         if(!fgets(line, sizeof line, stdin)) {
 160                 fprintf(stderr, "Error while reading stdin: %s\n", strerror(errno));
 161                 free(hostname);
 162                 return NULL;
 163         }
 164
 165         if(!rstrip(line)) {
 166                 if(hostname)
 167                         goto save;
 168                 else
 169                         goto again;
 170         }
 171
 172         for(char *p = line; *p; p++) {
 173                 if(isalnum(*p) || *p == '-' || *p == '.')
 174                         continue;
 175                 fprintf(stderr, "Invalid address or hostname.\n");
 176                 goto again;
 177         }
 178
 179         free(hostname);
 180         hostname = xstrdup(line);
 181
 182 save:
 183         if(filename) {
 184                 FILE *f = fopen(filename, "a");
 185                 if(f) {
 186                         fprintf(f, "\nAddress = %s\n", hostname);
 187                         fclose(f);
 188                 } else {
 189                         fprintf(stderr, "Could not append Address to %s: %s\n", filename, strerror(errno));
 190                 }
 191         }
 192
 193 done:
 194         if(port) {
 195                 if(strchr(hostname, ':'))
 196                         xasprintf(&hostport, "[%s]:%s", hostname, port);
 197                 else
 198                         xasprintf(&hostport, "%s:%s", hostname, port);
 199         } else {
 200                 hostport = hostname;
 201                 hostname = NULL;
 202         }
 203
 204         free(hostname);
 205         free(port);
 206         free(filename);
 207         return hostport;
 208 }
 209
 210 static bool fcopy(FILE *out, const char *filename) {
 211         FILE *in = fopen(filename, "r");
 212         if(!in) {
 213                 fprintf(stderr, "Could not open %s: %s\n", filename, strerror(errno));
 214                 return false;
 215         }
 216
 217         char buf[1024];
 218         size_t len;
 219         while((len = fread(buf, 1, sizeof buf, in)))
 220                 fwrite(buf, len, 1, out);
 221         fclose(in);
 222         return true;
 223 }
 224
 225 int cmd_invite(int argc, char *argv[]) {
 226         if(argc < 2) {
 227                 fprintf(stderr, "Not enough arguments!\n");
 228                 return 1;
 229         }
 230
 231         // Check validity of the new node's name
 232         if(!check_id(argv[1])) {
 233                 fprintf(stderr, "Invalid name for node.\n");
 234                 return 1;
 235         }
 236
 237         char *myname = get_my_name(true);
 238         if(!myname)
 239                 return 1;
 240
 241         // Ensure no host configuration file with that name exists
 242         char *filename = NULL;
 243         xasprintf(&filename, "%s" SLASH "hosts" SLASH "%s", confbase, argv[1]);
 244         if(!access(filename, F_OK)) {
 245                 free(filename);
 246                 fprintf(stderr, "A host config file for %s already exists!\n", argv[1]);
 247                 return 1;
 248         }
 249         free(filename);
 250
 251         // If a daemon is running, ensure no other nodes now about this name
 252         bool found = false;
 253         if(connect_tincd(false)) {
 254                 sendline(fd, "%d %d", CONTROL, REQ_DUMP_NODES);
 255
 256                 while(recvline(fd, line, sizeof line)) {
 257                         char node[4096];
 258                         int code, req;
 259                         if(sscanf(line, "%d %d %s", &code, &req, node) != 3)
 260                                 break;
 261                         if(!strcmp(node, argv[1]))
 262                                 found = true;
 263                 }
 264
 265                 if(found) {
 266                         fprintf(stderr, "A node with name %s is already known!\n", argv[1]);
 267                         return 1;
 268                 }
 269         }
 270
 271         char hash[25];
 272
 273         xasprintf(&filename, "%s" SLASH "invitations", confbase);
 274         if(mkdir(filename, 0700) && errno != EEXIST) {
 275                 fprintf(stderr, "Could not create directory %s: %s\n", filename, strerror(errno));
 276                 free(filename);
 277                 return 1;
 278         }
 279
 280         // Count the number of valid invitations, clean up old ones
 281         DIR *dir = opendir(filename);
 282         if(!dir) {
 283                 fprintf(stderr, "Could not read directory %s: %s\n", filename, strerror(errno));
 284                 free(filename);
 285                 return 1;
 286         }
 287
 288         errno = 0;
 289         int count = 0;
 290         struct dirent *ent;
 291         time_t deadline = time(NULL) - 604800; // 1 week in the past
 292
 293         while((ent = readdir(dir))) {
 294                 if(strlen(ent->d_name) != 24)
 295                         continue;
 296                 char *invname;
 297                 struct stat st;
 298                 xasprintf(&invname, "%s" SLASH "%s", filename, ent->d_name);
 299                 if(!stat(invname, &st)) {
 300                         if(deadline < st.st_mtime)
 301                                 count++;
 302                         else
 303                                 unlink(invname);
 304                 } else {
 305                         fprintf(stderr, "Could not stat %s: %s\n", invname, strerror(errno));
 306                         errno = 0;
 307                 }
 308                 free(invname);
 309         }
 310
 311         if(errno) {
 312                 fprintf(stderr, "Error while reading directory %s: %s\n", filename, strerror(errno));
 313                 closedir(dir);
 314                 free(filename);
 315                 return 1;
 316         }
 317
 318         closedir(dir);
 319         free(filename);
 320
 321         ecdsa_t *key;
 322         xasprintf(&filename, "%s" SLASH "invitations" SLASH "ecdsa_key.priv", confbase);
 323
 324         // Remove the key if there are no outstanding invitations.
 325         if(!count)
 326                 unlink(filename);
 327
 328         // Create a new key if necessary.
 329         FILE *f = fopen(filename, "r");
 330         if(!f) {
 331                 if(errno != ENOENT) {
 332                         fprintf(stderr, "Could not read %s: %s\n", filename, strerror(errno));
 333                         free(filename);
 334                         return 1;
 335                 }
 336
 337                 key = ecdsa_generate();
 338                 if(!key) {
 339                         free(filename);
 340                         return 1;
 341                 }
 342                 f = fopen(filename, "w");
 343                 if(!f) {
 344                         fprintf(stderr, "Could not write %s: %s\n", filename, strerror(errno));
 345                         free(filename);
 346                         return 1;
 347                 }
 348                 chmod(filename, 0600);
 349                 ecdsa_write_pem_private_key(key, f);
 350                 fclose(f);
 351
 352                 if(connect_tincd(false))
 353                         sendline(fd, "%d %d", CONTROL, REQ_RELOAD);
 354         } else {
 355                 key = ecdsa_read_pem_private_key(f);
 356                 fclose(f);
 357                 if(!key)
 358                         fprintf(stderr, "Could not read private key from %s\n", filename);
 359         }
 360
 361         free(filename);
 362         if(!key)
 363                 return 1;
 364
 365         // Create a hash of the key.
 366         char *fingerprint = ecdsa_get_base64_public_key(key);
 367         digest_t *digest = digest_open_by_name("sha256", 18);
 368         if(!digest)
 369                 abort();
 370         digest_create(digest, fingerprint, strlen(fingerprint), hash);
 371         b64encode_urlsafe(hash, hash, 18);
 372
 373         // Create a random cookie for this invitation.
 374         char cookie[25];
 375         randomize(cookie, 18);
 376
 377         // Create a filename that doesn't reveal the cookie itself
 378         char buf[18 + strlen(fingerprint)];
 379         char cookiehash[25];
 380         memcpy(buf, cookie, 18);
 381         memcpy(buf + 18, fingerprint, sizeof buf - 18);
 382         digest_create(digest, buf, sizeof buf, cookiehash);
 383         b64encode_urlsafe(cookiehash, cookiehash, 18);
 384
 385         b64encode_urlsafe(cookie, cookie, 18);
 386
 387         // Create a file containing the details of the invitation.
 388         xasprintf(&filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookiehash);
 389         int ifd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
 390         if(!ifd) {
 391                 fprintf(stderr, "Could not create invitation file %s: %s\n", filename, strerror(errno));
 392                 free(filename);
 393                 return 1;
 394         }
 395         f = fdopen(ifd, "w");
 396         if(!f)
 397                 abort();
 398
 399         // Get the local address
 400         char *address = get_my_hostname();
 401
 402         // Fill in the details.
 403         fprintf(f, "Name = %s\n", argv[1]);
 404         if(netname)
 405                 fprintf(f, "NetName = %s\n", netname);
 406         fprintf(f, "ConnectTo = %s\n", myname);
 407
 408         // Copy Broadcast and Mode
 409         FILE *tc = fopen(tinc_conf, "r");
 410         if(tc) {
 411                 char buf[1024];
 412                 while(fgets(buf, sizeof buf, tc)) {
 413                         if((!strncasecmp(buf, "Mode", 4) && strchr(" \t=", buf[4]))
 414                                         || (!strncasecmp(buf, "Broadcast", 9) && strchr(" \t=", buf[9]))) {
 415                                 fputs(buf, f);
 416                                 // Make sure there is a newline character.
 417                                 if(!strchr(buf, '\n'))
 418                                         fputc('\n', f);
 419                         }
 420                 }
 421                 fclose(tc);
 422         }
 423
 424         fprintf(f, "#---------------------------------------------------------------#\n");
 425         fprintf(f, "Name = %s\n", myname);
 426
 427         char *filename2;
 428         xasprintf(&filename2, "%s" SLASH "hosts" SLASH "%s", confbase, myname);
 429         fcopy(f, filename2);
 430         fclose(f);
 431         free(filename2);
 432
 433         // Create an URL from the local address, key hash and cookie
 434         char *url;
 435         xasprintf(&url, "%s/%s%s", address, hash, cookie);
 436
 437         // Call the inviation-created script
 438         char *envp[6] = {};
 439         xasprintf(&envp[0], "NAME=%s", myname);
 440         xasprintf(&envp[1], "NETNAME=%s", netname);
 441         xasprintf(&envp[2], "NODE=%s", argv[1]);
 442         xasprintf(&envp[3], "INVITATION_FILE=%s", filename);
 443         xasprintf(&envp[4], "INVITATION_URL=%s", url);
 444         execute_script("invitation-created", envp);
 445         for(int i = 0; i < 6 && envp[i]; i++)
 446                 free(envp[i]);
 447
 448         puts(url);
 449         free(url);
 450         free(filename);
 451         free(address);
 452
 453         return 0;
 454 }
 455
 456 static int sock;
 457 static char cookie[18];
 458 static sptps_t sptps;
 459 static char *data;
 460 static size_t datalen;
 461 static bool success = false;
 462
 463 static char cookie[18], hash[18];
 464
 465 static char *get_line(const char **data) {
 466         if(!data || !*data)
 467                 return NULL;
 468
 469         if(!**data) {
 470                 *data = NULL;
 471                 return NULL;
 472         }
 473
 474         static char line[1024];
 475         const char *end = strchr(*data, '\n');
 476         size_t len = end ? end - *data : strlen(*data);
 477         if(len >= sizeof line) {
 478                 fprintf(stderr, "Maximum line length exceeded!\n");
 479                 return NULL;
 480         }
 481         if(len && !isprint(**data))
 482                 abort();
 483
 484         memcpy(line, *data, len);
 485         line[len] = 0;
 486
 487         if(end)
 488                 *data = end + 1;
 489         else
 490                 *data = NULL;
 491
 492         return line;
 493 }
 494
 495 static char *get_value(const char *data, const char *var) {
 496         char *line = get_line(&data);
 497         if(!line)
 498                 return NULL;
 499
 500         char *sep = line + strcspn(line, " \t=");
 501         char *val = sep + strspn(sep, " \t");
 502         if(*val == '=')
 503                 val += 1 + strspn(val + 1, " \t");
 504         *sep = 0;
 505         if(strcasecmp(line, var))
 506                 return NULL;
 507         return val;
 508 }
 509
 510 static char *grep(const char *data, const char *var) {
 511         static char value[1024];
 512
 513         const char *p = data;
 514         int varlen = strlen(var);
 515
 516         // Skip all lines not starting with var
 517         while(strncasecmp(p, var, varlen) || !strchr(" \t=", p[varlen])) {
 518                 p = strchr(p, '\n');
 519                 if(!p)
 520                         break;
 521                 else
 522                         p++;
 523         }
 524
 525         if(!p)
 526                 return NULL;
 527
 528         p += varlen;
 529         p += strspn(p, " \t");
 530         if(*p == '=')
 531                 p += 1 + strspn(p + 1, " \t");
 532
 533         const char *e = strchr(p, '\n');
 534         if(!e)
 535                 return xstrdup(p);
 536
 537         if(e - p >= sizeof value) {
 538                 fprintf(stderr, "Maximum line length exceeded!\n");
 539                 return NULL;
 540         }
 541
 542         memcpy(value, p, e - p);
 543         value[e - p] = 0;
 544         return value;
 545 }
 546
 547 static bool finalize_join(void) {
 548         char *name = xstrdup(get_value(data, "Name"));
 549         if(!name) {
 550                 fprintf(stderr, "No Name found in invitation!\n");
 551                 return false;
 552         }
 553
 554         if(!check_id(name)) {
 555                 fprintf(stderr, "Invalid Name found in invitation: %s!\n", name);
 556                 return false;
 557         }
 558
 559         if(!netname)
 560                 netname = grep(data, "NetName");
 561
 562         bool ask_netname = false;
 563         char temp_netname[32];
 564
 565 make_names:
 566         if(!confbasegiven) {
 567                 free(confbase);
 568                 confbase = NULL;
 569         }
 570
 571         make_names();
 572
 573         free(tinc_conf);
 574         free(hosts_dir);
 575
 576         xasprintf(&tinc_conf, "%s" SLASH "tinc.conf", confbase);
 577         xasprintf(&hosts_dir, "%s" SLASH "hosts", confbase);
 578
 579         if(!access(tinc_conf, F_OK)) {
 580                 fprintf(stderr, "Configuration file %s already exists!\n", tinc_conf);
 581                 if(confbasegiven)
 582                         return false;
 583
 584                 // Generate a random netname, ask for a better one later.
 585                 ask_netname = true;
 586                 snprintf(temp_netname, sizeof temp_netname, "join_%x", rand());
 587                 netname = temp_netname;
 588                 goto make_names;
 589         }
 590
 591         if(mkdir(confbase, 0777) && errno != EEXIST) {
 592                 fprintf(stderr, "Could not create directory %s: %s\n", confbase, strerror(errno));
 593                 return false;
 594         }
 595
 596         if(mkdir(hosts_dir, 0777) && errno != EEXIST) {
 597                 fprintf(stderr, "Could not create directory %s: %s\n", hosts_dir, strerror(errno));
 598                 return false;
 599         }
 600
 601         FILE *f = fopen(tinc_conf, "w");
 602         if(!f) {
 603                 fprintf(stderr, "Could not create file %s: %s\n", tinc_conf, strerror(errno));
 604                 return false;
 605         }
 606
 607         fprintf(f, "Name = %s\n", name);
 608
 609         char *filename;
 610         xasprintf(&filename, "%s" SLASH "%s", hosts_dir, name);
 611         FILE *fh = fopen(filename, "w");
 612         if(!fh) {
 613                 fprintf(stderr, "Could not create file %s: %s\n", filename, strerror(errno));
 614                 return false;
 615         }
 616
 617         // Filter first chunk on approved keywords, split between tinc.conf and hosts/Name
 618         // Other chunks go unfiltered to their respective host config files
 619         const char *p = data;
 620         char *l, *value;
 621
 622         while((l = get_line(&p))) {
 623                 // Ignore comments
 624                 if(*l == '#')
 625                         continue;
 626
 627                 // Split line into variable and value
 628                 int len = strcspn(l, "\t =");
 629                 value = l + len;
 630                 value += strspn(value, "\t ");
 631                 if(*value == '=') {
 632                         value++;
 633                         value += strspn(value, "\t ");
 634                 }
 635                 l[len] = 0;
 636
 637                 // Is it a Name?
 638                 if(!strcasecmp(l, "Name"))
 639                         if(strcmp(value, name))
 640                                 break;
 641                         else
 642                                 continue;
 643                 else if(!strcasecmp(l, "NetName"))
 644                         continue;
 645
 646                 // Check the list of known variables
 647                 bool found = false;
 648                 int i;
 649                 for(i = 0; variables[i].name; i++) {
 650                         if(strcasecmp(l, variables[i].name))
 651                                 continue;
 652                         found = true;
 653                         break;
 654                 }
 655
 656                 // Ignore unknown and unsafe variables
 657                 if(!found) {
 658                         fprintf(stderr, "Ignoring unknown variable '%s' in invitation.\n", l);
 659                         continue;
 660                 } else if(!(variables[i].type & VAR_SAFE)) {
 661                         fprintf(stderr, "Ignoring unsafe variable '%s' in invitation.\n", l);
 662                         continue;
 663                 }
 664
 665                 // Copy the safe variable to the right config file
 666                 fprintf(variables[i].type & VAR_HOST ? fh : f, "%s = %s\n", l, value);
 667         }
 668
 669         fclose(f);
 670         free(filename);
 671
 672         while(l && !strcasecmp(l, "Name")) {
 673                 if(!check_id(value)) {
 674                         fprintf(stderr, "Invalid Name found in invitation.\n");
 675                         return false;
 676                 }
 677
 678                 if(!strcmp(value, name)) {
 679                         fprintf(stderr, "Secondary chunk would overwrite our own host config file.\n");
 680                         return false;
 681                 }
 682
 683                 xasprintf(&filename, "%s" SLASH "%s", hosts_dir, value);
 684                 f = fopen(filename, "w");
 685
 686                 if(!f) {
 687                         fprintf(stderr, "Could not create file %s: %s\n", filename, strerror(errno));
 688                         return false;
 689                 }
 690
 691                 while((l = get_line(&p))) {
 692                         if(!strcmp(l, "#---------------------------------------------------------------#"))
 693                                 continue;
 694                         int len = strcspn(l, "\t =");
 695                         if(len == 4 && !strncasecmp(l, "Name", 4)) {
 696                                 value = l + len;
 697                                 value += strspn(value, "\t ");
 698                                 if(*value == '=') {
 699                                         value++;
 700                                         value += strspn(value, "\t ");
 701                                 }
 702                                 l[len] = 0;
 703                                 break;
 704                         }
 705
 706                         fputs(l, f);
 707                         fputc('\n', f);
 708                 }
 709
 710                 fclose(f);
 711                 free(filename);
 712         }
 713
 714         // Generate our key and send a copy to the server
 715         ecdsa_t *key = ecdsa_generate();
 716         if(!key)
 717                 return false;
 718
 719         char *b64key = ecdsa_get_base64_public_key(key);
 720         if(!b64key)
 721                 return false;
 722
 723         xasprintf(&filename, "%s" SLASH "ecdsa_key.priv", confbase);
 724         f = fopenmask(filename, "w", 0600);
 725
 726         if(!ecdsa_write_pem_private_key(key, f)) {
 727                 fprintf(stderr, "Error writing private key!\n");
 728                 ecdsa_free(key);
 729                 fclose(f);
 730                 return false;
 731         }
 732
 733         fclose(f);
 734
 735         fprintf(fh, "ECDSAPublicKey = %s\n", b64key);
 736
 737         sptps_send_record(&sptps, 1, b64key, strlen(b64key));
 738         free(b64key);
 739
 740
 741         rsa_t *rsa = rsa_generate(2048, 0x1001);
 742         xasprintf(&filename, "%s" SLASH "rsa_key.priv", confbase);
 743         f = fopenmask(filename, "w", 0600);
 744
 745         rsa_write_pem_private_key(rsa, f);
 746         fclose(f);
 747
 748         rsa_write_pem_public_key(rsa, fh);
 749         fclose(fh);
 750
 751         ecdsa_free(key);
 752         rsa_free(rsa);
 753
 754         check_port(name);
 755
 756 ask_netname:
 757         if(ask_netname && tty) {
 758                 fprintf(stderr, "Enter a new netname: ");
 759                 if(!fgets(line, sizeof line, stdin)) {
 760                         fprintf(stderr, "Error while reading stdin: %s\n", strerror(errno));
 761                         return false;
 762                 }
 763                 if(!*line || *line == '\n')
 764                         goto ask_netname;
 765
 766                 line[strlen(line) - 1] = 0;
 767
 768                 char *newbase;
 769                 xasprintf(&newbase, CONFDIR SLASH "tinc" SLASH "%s", line);
 770                 if(rename(confbase, newbase)) {
 771                         fprintf(stderr, "Error trying to rename %s to %s: %s\n", confbase, newbase, strerror(errno));
 772                         free(newbase);
 773                         goto ask_netname;
 774                 }
 775
 776                 free(newbase);
 777                 netname = line;
 778                 make_names();
 779         }
 780
 781         fprintf(stderr, "Configuration stored in: %s\n", confbase);
 782
 783         return true;
 784 }
 785
 786
 787 static bool invitation_send(void *handle, uint8_t type, const char *data, size_t len) {
 788         while(len) {
 789                 int result = send(sock, data, len, 0);
 790                 if(result == -1 && errno == EINTR)
 791                         continue;
 792                 else if(result <= 0)
 793                         return false;
 794                 data += result;
 795                 len -= result;
 796         }
 797         return true;
 798 }
 799
 800 static bool invitation_receive(void *handle, uint8_t type, const char *msg, uint16_t len) {
 801         switch(type) {
 802                 case SPTPS_HANDSHAKE:
 803                         return sptps_send_record(&sptps, 0, cookie, sizeof cookie);
 804
 805                 case 0:
 806                         data = xrealloc(data, datalen + len + 1);
 807                         memcpy(data + datalen, msg, len);
 808                         datalen += len;
 809                         data[datalen] = 0;
 810                         break;
 811
 812                 case 1:
 813                         return finalize_join();
 814
 815                 case 2:
 816                         fprintf(stderr, "Invitation succesfully accepted.\n");
 817                         shutdown(sock, SHUT_RDWR);
 818                         success = true;
 819                         break;
 820
 821                 default:
 822                         return false;
 823         }
 824
 825         return true;
 826 }
 827
 828 int cmd_join(int argc, char *argv[]) {
 829         free(data);
 830         data = NULL;
 831         datalen = 0;
 832
 833         if(argc > 2) {
 834                 fprintf(stderr, "Too many arguments!\n");
 835                 return 1;
 836         }
 837
 838         // Make sure confbase exists and is accessible.
 839         if(!confbase_given && mkdir(confdir, 0755) && errno != EEXIST) {
 840                 fprintf(stderr, "Could not create directory %s: %s\n", confdir, strerror(errno));
 841                 return 1;
 842         }
 843
 844         if(mkdir(confbase, 0777) && errno != EEXIST) {
 845                 fprintf(stderr, "Could not create directory %s: %s\n", confbase, strerror(errno));
 846                 return 1;
 847         }
 848
 849         if(access(confbase, R_OK | W_OK | X_OK)) {
 850                 fprintf(stderr, "No permission to write in directory %s: %s\n", confbase, strerror(errno));
 851                 return 1;
 852         }
 853
 854         // If a netname or explicit configuration directory is specified, check for an existing tinc.conf.
 855         if((netname || confbasegiven) && !access(tinc_conf, F_OK)) {
 856                 fprintf(stderr, "Configuration file %s already exists!\n", tinc_conf);
 857                 return 1;
 858         }
 859
 860         // Either read the invitation from the command line or from stdin.
 861         char *invitation;
 862
 863         if(argc > 1) {
 864                 invitation = argv[1];
 865         } else {
 866                 if(tty)
 867                         fprintf(stderr, "Enter invitation URL: ");
 868                 errno = EPIPE;
 869                 if(!fgets(line, sizeof line, stdin)) {
 870                         fprintf(stderr, "Error while reading stdin: %s\n", strerror(errno));
 871                         return false;
 872                 }
 873                 invitation = line;
 874         }
 875
 876         // Parse the invitation URL.
 877         rstrip(line);
 878
 879         char *slash = strchr(invitation, '/');
 880         if(!slash)
 881                 goto invalid;
 882
 883         *slash++ = 0;
 884
 885         if(strlen(slash) != 48)
 886                 goto invalid;
 887
 888         char *address = invitation;
 889         char *port = NULL;
 890         if(*address == '[') {
 891                 address++;
 892                 char *bracket = strchr(address, ']');
 893                 if(!bracket)
 894                         goto invalid;
 895                 *bracket = 0;
 896                 if(bracket[1] == ':')
 897                         port = bracket + 2;
 898         } else {
 899                 port = strchr(address, ':');
 900                 if(port)
 901                         *port++ = 0;
 902         }
 903
 904         if(!port || !*port)
 905                 port = "655";
 906
 907         if(!b64decode(slash, hash, 18) || !b64decode(slash + 24, cookie, 18))
 908                 goto invalid;
 909
 910         // Generate a throw-away key for the invitation.
 911         ecdsa_t *key = ecdsa_generate();
 912         if(!key)
 913                 return 1;
 914
 915         char *b64key = ecdsa_get_base64_public_key(key);
 916
 917         // Connect to the tinc daemon mentioned in the URL.
 918         struct addrinfo *ai = str2addrinfo(address, port, SOCK_STREAM);
 919         if(!ai)
 920                 return 1;
 921
 922         sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 923         if(sock <= 0) {
 924                 fprintf(stderr, "Could not open socket: %s\n", strerror(errno));
 925                 return 1;
 926         }
 927
 928         if(connect(sock, ai->ai_addr, ai->ai_addrlen)) {
 929                 fprintf(stderr, "Could not connect to %s port %s: %s\n", address, port, strerror(errno));
 930                 closesocket(sock);
 931                 return 1;
 932         }
 933
 934         fprintf(stderr, "Connected to %s port %s...\n", address, port);
 935
 936         // Tell him we have an invitation, and give him our throw-away key.
 937         int len = snprintf(line, sizeof line, "0 ?%s %d.%d\n", b64key, PROT_MAJOR, PROT_MINOR);
 938         if(len <= 0 || len >= sizeof line)
 939                 abort();
 940
 941         if(!sendline(sock, "0 ?%s %d.%d", b64key, PROT_MAJOR, 1)) {
 942                 fprintf(stderr, "Error sending request to %s port %s: %s\n", address, port, strerror(errno));
 943                 closesocket(sock);
 944                 return 1;
 945         }
 946
 947         char hisname[4096] = "";
 948         int code, hismajor, hisminor = 0;
 949
 950         if(!recvline(sock, line, sizeof line) || sscanf(line, "%d %s %d.%d", &code, hisname, &hismajor, &hisminor) < 3 || code != 0 || hismajor != PROT_MAJOR || !check_id(hisname) || !recvline(sock, line, sizeof line) || !rstrip(line) || sscanf(line, "%d ", &code) != 1 || code != ACK || strlen(line) < 3) {
 951                 fprintf(stderr, "Cannot read greeting from peer\n");
 952                 closesocket(sock);
 953                 return 1;
 954         }
 955
 956         // Check if the hash of the key he gave us matches the hash in the URL.
 957         char *fingerprint = line + 2;
 958         digest_t *digest = digest_open_by_name("sha256", 18);
 959         if(!digest)
 960                 abort();
 961         char hishash[18];
 962         if(!digest_create(digest, fingerprint, strlen(fingerprint), hishash)) {
 963                 fprintf(stderr, "Could not create digest\n%s\n", line + 2);
 964                 return 1;
 965         }
 966         if(memcmp(hishash, hash, 18)) {
 967                 fprintf(stderr, "Peer has an invalid key!\n%s\n", line + 2);
 968                 return 1;
 969
 970         }
 971
 972         ecdsa_t *hiskey = ecdsa_set_base64_public_key(fingerprint);
 973         if(!hiskey)
 974                 return 1;
 975
 976         // Start an SPTPS session
 977         if(!sptps_start(&sptps, NULL, true, false, key, hiskey, "tinc invitation", 15, invitation_send, invitation_receive))
 978                 return 1;
 979
 980         // Feed rest of input buffer to SPTPS
 981         if(!sptps_receive_data(&sptps, buffer, blen))
 982                 return 1;
 983
 984         while((len = recv(sock, line, sizeof line, 0))) {
 985                 if(len < 0) {
 986                         if(errno == EINTR)
 987                                 continue;
 988                         fprintf(stderr, "Error reading data from %s port %s: %s\n", address, port, strerror(errno));
 989                         return 1;
 990                 }
 991
 992                 if(!sptps_receive_data(&sptps, line, len))
 993                         return 1;
 994         }
 995
 996         sptps_stop(&sptps);
 997         ecdsa_free(hiskey);
 998         ecdsa_free(key);
 999         closesocket(sock);
1000
1001         if(!success) {
1002                 fprintf(stderr, "Connection closed by peer, invitation cancelled.\n");
1003                 return 1;
1004         }
1005
1006         return 0;
1007
1008 invalid:
1009         fprintf(stderr, "Invalid invitation URL.\n");
1010         return 1;
1011 }