trusts/trusts_policy.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <stdarg.h>
   4 #include <unistd.h>
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <netinet/in.h>
   8
   9 #ifndef __USE_MISC
  10 #define __USE_MISC /* inet_aton */
  11 #endif
  12
  13 #include <arpa/inet.h>
  14 #include <sys/un.h>
  15 #include <sys/poll.h>
  16 #include <errno.h>
  17 #include <fcntl.h>
  18
  19 #include "../lib/hmac.h"
  20 #include "../core/events.h"
  21 #include "../core/schedule.h"
  22 #include "../core/nsmalloc.h"
  23 #include "../core/hooks.h"
  24 #include "../core/config.h"
  25 #include "../control/control.h"
  26 #include "../lib/irc_string.h"
  27 #include "../irc/irc.h"
  28 #include "../glines/glines.h"
  29 #include "trusts.h"
  30
  31 static int countext, enforcepolicy;
  32
  33 #define TRUSTBUFSIZE 8192
  34 #define TRUSTPASSLEN 128
  35 #define NONCELEN 16
  36
  37 typedef struct trustsocket {
  38   int fd;
  39   int authed;
  40   char authuser[SERVERLEN+1];
  41   char buf[TRUSTBUFSIZE];
  42   unsigned char nonce[NONCELEN];
  43   int size;
  44   time_t connected;
  45   time_t timeout;
  46   int accepted;
  47   int rejected;
  48
  49   struct trustsocket *next;
  50 } trustsocket;
  51
  52 static trustsocket *tslist;
  53 static int listenerfd = -1;
  54 static FILE *urandom;
  55
  56 typedef struct trustaccount {
  57   int used;
  58   char server[SERVERLEN+1];
  59   char password[TRUSTPASSLEN+1];
  60 } trustaccount;
  61
  62 trustaccount trustaccounts[MAXSERVERS];
  63
  64 static int checkconnectionth(const char *username, struct irc_in_addr *ip, trusthost *th, int hooknum, int usercountadjustment, char *message, size_t messagelen) {
  65   trustgroup *tg;
  66
  67   if(messagelen>0)
  68     message[0] = '\0';
  69
  70   if(!th)
  71     return POLICY_SUCCESS;
  72
  73   tg = th->group;
  74
  75   /*
  76    * the purpose of this logic is to avoid spam like this:
  77    * WARNING: tgX exceeded limit: 11 connected vs 10 max
  78    * (goes back down to 10)
  79    * WARNING: tgX exceeded limit: 11 connected vs 10 max
  80    */
  81
  82   if(hooknum == HOOK_TRUSTS_NEWNICK) {
  83     patricia_node_t *head, *node;
  84     int nodecount = 0;
  85
  86     head = refnode(iptree, ip, th->nodebits);
  87     PATRICIA_WALK(head, node)
  88     {
  89       nodecount += node->usercount;
  90     }
  91     PATRICIA_WALK_END;
  92     derefnode(iptree, head);
  93
  94     if(th->maxpernode && nodecount + usercountadjustment > th->maxpernode) {
  95       controlwall(NO_OPER, NL_TRUSTS, "Hard connection limit exceeded on subnet: %s (group: %s): %d connected, %d max.", trusts_cidr2str(ip, th->nodebits), tg->name->content, nodecount, th->maxpernode);
  96       snprintf(message, messagelen, "Too many connections from your host (%s) - see http://www.quakenet.org/help/trusts/connection-limit for details.", IPtostr(*ip));
  97       return POLICY_FAILURE_NODECOUNT;
  98     }
  99
 100     if(tg->trustedfor && tg->count + usercountadjustment > tg->trustedfor) {
 101       if(tg->count > (long)tg->exts[countext]) {
 102         tg->exts[countext] = (void *)(long)tg->count;
 103
 104         controlwall(NO_OPER, NL_TRUSTS, "Hard connection limit exceeded (group %s): %d connected, %d max.", tg->name->content, tg->count, tg->trustedfor);
 105         snprintf(message, messagelen, "Too many connections from your trust (%s) - see http://www.quakenet.org/help/trusts/connection-limit for details.", IPtostr(*ip));
 106         return POLICY_FAILURE_GROUPCOUNT;
 107       }
 108
 109       snprintf(message, messagelen, "Trust has %d out of %d allowed connections.", tg->count + usercountadjustment, tg->trustedfor);
 110     }
 111
 112     if((tg->flags & TRUST_ENFORCE_IDENT) && (username[0] == '~')) {
 113       controlwall(NO_OPER, NL_TRUSTS, "Ident required: %s@%s (group: %s).", username, IPtostr(*ip), tg->name->content);
 114       snprintf(message, messagelen, "IDENTD required from your host (%s) - see http://www.quakenet.org/help/trusts/connection-limit for details.", IPtostr(*ip));
 115       return POLICY_FAILURE_IDENTD;
 116     }
 117
 118     if(tg->maxperident > 0) {
 119       int identcount = 0;
 120       trusthost *th2;
 121       nick *tnp;
 122
 123       for(th2=tg->hosts;th2;th2=th2->next) {
 124         for(tnp=th2->users;tnp;tnp=nextbytrust(tnp)) {
 125           if(!ircd_strcmp(tnp->ident, username))
 126             identcount++;
 127         }
 128       }
 129
 130       if(identcount + usercountadjustment > tg->maxperident) {
 131         controlwall(NO_OPER, NL_TRUSTS, "Hard ident limit exceeded: %s@%s (group: %s): %d connected, %d max.", username, IPtostr(*ip), tg->name->content, identcount, tg->maxperident);
 132         snprintf(message, messagelen, "Too many connections from your username (%s@%s) - see http://www.quakenet.org/help/trusts/connection-limit for details.", username, IPtostr(*ip));
 133         return POLICY_FAILURE_IDENTCOUNT;
 134       }
 135     }
 136   } else {
 137     if(tg->count < tg->maxusage)
 138       tg->exts[countext] = (void *)(long)tg->count;
 139   }
 140
 141   return POLICY_SUCCESS;
 142 }
 143
 144 static int checkconnection(const char *username, struct irc_in_addr *ip, int hooknum, int cloneadjustment, char *message, size_t messagelen) {
 145   struct irc_in_addr ip_canonicalized;
 146   ip_canonicalize_tunnel(&ip_canonicalized, ip);
 147
 148   return checkconnectionth(username, &ip_canonicalized, th_getbyhost(ip), hooknum, cloneadjustment, message, messagelen);
 149 }
 150
 151 static int trustdowrite(trustsocket *sock, char *format, ...) {
 152   char buf[1024];
 153   va_list va;
 154   int r;
 155
 156   va_start(va, format);
 157   r = vsnprintf(buf, sizeof(buf), format, va);
 158   va_end(va);
 159
 160   if(r >= sizeof(buf))
 161     r = sizeof(buf) - 1;
 162
 163   buf[r] = '\n';
 164
 165   if(write(sock->fd, buf, r + 1) != r + 1)
 166     return 0;
 167   return 1;
 168 }
 169
 170 static int policycheck_auth(trustsocket *sock, const char *sequence_id, const char *username, const char *host) {
 171   char message[512];
 172   int verdict;
 173   struct irc_in_addr ip;
 174   unsigned char bits;
 175
 176   if(!ipmask_parse(host, &ip, &bits)) {
 177     sock->accepted++;
 178     return trustdowrite(sock, "PASS %s", sequence_id);
 179   }
 180
 181   verdict = checkconnection(username, &ip, HOOK_TRUSTS_NEWNICK, 1, message, sizeof(message));
 182
 183   if (verdict == POLICY_SUCCESS) {
 184     sock->accepted++;
 185
 186     if(message[0])
 187       return trustdowrite(sock, "PASS %s %s", sequence_id, message);
 188     else
 189       return trustdowrite(sock, "PASS %s", sequence_id);
 190   } else {
 191     sock->rejected++;
 192
 193     controlwall(NO_OPER, NL_TRUSTS, "Rejected connection from %s@%s using IAuth: %s", username, host, message);
 194     return trustdowrite(sock, "KILL %s %s", sequence_id, message);
 195   }
 196 }
 197
 198 static int trustkillconnection(trustsocket *sock, char *reason) {
 199   trustdowrite(sock, "QUIT %s", reason);
 200   return 0;
 201 }
 202
 203 static void trustfreeconnection(trustsocket *sock) {
 204   trustsocket **pnext = &tslist;
 205
 206   for(trustsocket *ts=tslist;ts;ts=ts->next) {
 207     if(ts == sock) {
 208       deregisterhandler(sock->fd, 1);
 209       *pnext = sock->next;
 210       nsfree(POOL_TRUSTS, sock);
 211       break;
 212     }
 213
 214     pnext = &(sock->next);
 215   }
 216 }
 217
 218 static int handletrustauth(trustsocket *sock, char *server_name, char *mac) {
 219   int i;
 220   char *password = NULL;
 221   unsigned char digest[16];
 222   char noncehexbuf[NONCELEN * 2 + 1];
 223   char hexbuf[sizeof(digest) * 2 + 1];
 224
 225   for(i=0;i<MAXSERVERS;i++) {
 226     if(trustaccounts[i].used && strcmp(trustaccounts[i].server, server_name) == 0) {
 227       password = trustaccounts[i].password;
 228       break;
 229     }
 230   }
 231
 232   if (!password)
 233     return trustkillconnection(sock, "Invalid servername.");
 234
 235   hmacmd5 h;
 236   hmacmd5_init(&h, (unsigned char *)password, strlen(password));
 237   hmacmd5_update(&h, (unsigned char *)hmac_printhex(sock->nonce, noncehexbuf, NONCELEN), NONCELEN * 2);
 238   hmacmd5_final(&h, digest);
 239   if(hmac_strcmp(mac, hmac_printhex(digest, hexbuf, sizeof(digest))))
 240     return trustkillconnection(sock, "Bad MAC.");
 241
 242   sock->authed = 1;
 243   strncpy(sock->authuser, server_name, SERVERLEN);
 244   return trustdowrite(sock, "AUTHOK");
 245 }
 246
 247 #define MAXTOKENS 10
 248 static int handletrustline(trustsocket *sock, char *line) {
 249   char *command, *p, *lastpos;
 250   char *tokens[MAXTOKENS];
 251   int tokensfound = -1;
 252
 253   for(command=lastpos=p=line;*p;p++) {
 254     if(*p == ' ') {
 255       *p = '\0';
 256       if(tokensfound == MAXTOKENS)
 257         return trustkillconnection(sock, "too many tokens");
 258
 259       if(tokensfound >= 0) {
 260         tokens[tokensfound++] = lastpos;
 261       } else {
 262         tokensfound++;
 263       }
 264       lastpos = p + 1;
 265     }
 266   }
 267   if(lastpos != p) {
 268     if(tokensfound == MAXTOKENS)
 269       return trustkillconnection(sock, "too many tokens");
 270     tokens[tokensfound++] = lastpos;
 271   }
 272
 273   if(!sock->authed && !strcmp("AUTH", command)) {
 274     if(tokensfound != 2)
 275       return trustkillconnection(sock, "incorrect arg count for command.");
 276
 277     return handletrustauth(sock, tokens[0], tokens[1]);
 278   } else if(sock->authed && !strcmp("CHECK", command)) {
 279     if(tokensfound != 3)
 280       return trustkillconnection(sock, "incorrect arg count for command.");
 281
 282     policycheck_auth(sock, tokens[0], tokens[1], tokens[2]);
 283     return 1;
 284   } else {
 285     Error("trusts_policy", ERR_WARNING, "Bad command: %s", command);
 286     return 0;
 287   }
 288 }
 289
 290 static trustsocket *findtrustsocketbyfd(int fd) {
 291   for(trustsocket *ts=tslist;ts;ts=ts->next)
 292     if(ts->fd==fd)
 293       return ts;
 294
 295   return NULL;
 296 }
 297
 298 static int handletrustclient(trustsocket *sock) {
 299   int r, remaining = TRUSTBUFSIZE - sock->size, i;
 300   char *lastpos, *c;
 301
 302   if(!remaining) {
 303     trustkillconnection(sock, "Buffer overflow.");
 304     return 0;
 305   }
 306
 307   r = read(sock->fd, sock->buf + sock->size, remaining);
 308   if(r <= 0)
 309     return 0;
 310
 311   sock->size+=r;
 312   lastpos = sock->buf;
 313
 314   for(c=sock->buf,i=0;i<sock->size;i++,c++) {
 315     if(*c != '\n')
 316       continue;
 317     *c = '\0';
 318     if(!handletrustline(sock, lastpos))
 319       return 0;
 320
 321     lastpos = c + 1; /* is this ok? */
 322   }
 323   sock->size-=lastpos - sock->buf;
 324   memmove(sock->buf, lastpos, sock->size);
 325
 326   return 1;
 327 }
 328
 329 static void processtrustclient(int fd, short events) {
 330   trustsocket *sock = findtrustsocketbyfd(fd);
 331
 332   if(!sock)
 333     return;
 334
 335   if(events & POLLIN)
 336     if(!handletrustclient(sock))
 337       trustfreeconnection(sock);
 338 }
 339
 340 static void trustdotimeout(void *arg) {
 341   time_t t = time(NULL);
 342   trustsocket **pnext, *next, *sock;
 343
 344   pnext = &tslist;
 345
 346   for(sock=tslist;sock;) {
 347     next = sock->next;
 348
 349     if(!sock->authed && t >= sock->timeout) {
 350       trustkillconnection(sock, "Auth timeout.");
 351       deregisterhandler(sock->fd, 1);
 352       *pnext = sock->next;
 353       nsfree(POOL_TRUSTS, sock);
 354     } else {
 355       pnext = &(sock->next);
 356     }
 357
 358     sock=next;
 359   }
 360 }
 361
 362 static void processtrustlistener(int fd, short events) {
 363   if(events & POLLIN) {
 364     trustsocket *sock;
 365     char buf[NONCELEN * 2 + 1];
 366
 367     int newfd = accept(fd, NULL, NULL), flags;
 368     if(newfd == -1)
 369       return;
 370
 371     flags = fcntl(newfd, F_GETFL, 0);
 372     if(flags < 0) {
 373       Error("trusts_policy", ERR_WARNING, "Unable to set socket non-blocking.");
 374       close(newfd);
 375       return;
 376     }
 377
 378     if(fcntl(fd, F_SETFL, flags|O_NONBLOCK) < 0) {
 379       Error("trusts_policy", ERR_WARNING, "Unable to set socket non-blocking.");
 380       close(newfd);
 381       return;
 382     }
 383
 384     registerhandler(newfd, POLLIN|POLLERR|POLLHUP, processtrustclient);
 385
 386     sock = nsmalloc(POOL_TRUSTS, sizeof(trustsocket));
 387     if(!sock) {
 388       deregisterhandler(newfd, 1);
 389       return;
 390     }
 391
 392     sock->fd = newfd;
 393     sock->next = tslist;
 394     tslist = sock;
 395
 396     if(fread((char *)sock->nonce, 1, NONCELEN, urandom) != NONCELEN) {
 397       Error("trusts_policy", ERR_WARNING, "Error getting random bytes.");
 398       deregisterhandler(newfd, 1);
 399       tslist = sock->next;
 400       nsfree(POOL_TRUSTS, sock);
 401     } else {
 402       sock->authed = 0;
 403       sock->size = 0;
 404       sock->connected = time(NULL);
 405       sock->timeout = time(NULL) + 30;
 406       sock->accepted = 0;
 407       sock->rejected = 0;
 408       if(!trustdowrite(sock, "AUTH %s", hmac_printhex(sock->nonce, buf, NONCELEN))) {
 409         Error("trusts_policy", ERR_WARNING, "Error writing auth to fd %d.", newfd);
 410         deregisterhandler(newfd, 1);
 411         tslist = sock->next;
 412         nsfree(POOL_TRUSTS, sock);
 413         return;
 414       }
 415     }
 416   }
 417 }
 418
 419 static int createlistenersock(int port) {
 420   struct sockaddr_in s;
 421   int fd;
 422   int optval;
 423
 424   memset(&s, 0, sizeof(struct sockaddr_in));
 425   s.sin_family = AF_INET;
 426   s.sin_addr.s_addr = INADDR_ANY;
 427   s.sin_port = htons(port);
 428
 429   fd = socket(PF_INET, SOCK_STREAM, 0);
 430   if(fd < 0) {
 431     Error("trusts_policy", ERR_WARNING, "Unable to get socket for trustfd.");
 432     return -1;
 433   }
 434
 435   optval = 1;
 436   setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval));
 437
 438   if(bind(fd, (struct sockaddr *)&s, sizeof(struct sockaddr_in)) < 0) {
 439     Error("trusts_policy", ERR_WARNING, "Unable to bind trustfd.");
 440     close(fd);
 441     return -1;
 442   }
 443
 444   if(listen(fd, 5) < 0) {
 445     Error("trusts_policy", ERR_WARNING, "Unable to listen on trustfd.");
 446     close(fd);
 447     return -1;
 448   }
 449
 450   registerhandler(fd, POLLIN, processtrustlistener);
 451
 452   return fd;
 453 }
 454
 455 static void policycheck_irc(int hooknum, void *arg) {
 456   void **args = arg;
 457   nick *np = args[0];
 458   long moving = (long)args[1];
 459   char message[512];
 460   int verdict;
 461
 462   if(moving)
 463     return;
 464
 465   verdict = checkconnectionth(np->ident, &np->p_nodeaddr, gettrusthost(np), hooknum, 0, message, sizeof(message));
 466
 467   if(!enforcepolicy)
 468     return;
 469
 470   switch (verdict) {
 471     case POLICY_FAILURE_NODECOUNT:
 472       glinebynick(np, POLICY_GLINE_DURATION, message, GLINE_IGNORE_TRUST, "trusts_policy");
 473       break;
 474     case POLICY_FAILURE_IDENTD:
 475       glinebyip("~*", &np->p_ipaddr, 128, POLICY_GLINE_DURATION, message, GLINE_ALWAYS_USER|GLINE_IGNORE_TRUST, "trusts_policy");
 476       break;
 477     case POLICY_FAILURE_IDENTCOUNT:
 478       glinebynick(np, POLICY_GLINE_DURATION, message, GLINE_ALWAYS_USER|GLINE_IGNORE_TRUST, "trusts_policy");
 479       break;
 480   }
 481 }
 482
 483 static int trusts_cmdtrustpolicy(void *source, int cargc, char **cargv) {
 484   nick *sender = source;
 485
 486   if(cargc < 1) {
 487     controlreply(sender, "Trust policy enforcement is currently %s.", enforcepolicy?"enabled":"disabled");
 488     return CMD_OK;
 489   }
 490
 491   enforcepolicy = atoi(cargv[0]);
 492   controlwall(NO_OPER, NL_TRUSTS, "%s %s trust policy enforcement.", controlid(sender), enforcepolicy?"enabled":"disabled");
 493   controlreply(sender, "Trust policy enforcement is now %s.", enforcepolicy?"enabled":"disabled");
 494
 495   return CMD_OK;
 496 }
 497
 498 static int trusts_cmdtrustsockets(void *source, int cargc, char **cargv) {
 499   nick *sender = source;
 500   time_t now;
 501   trustsocket *sock;
 502
 503   time(&now);
 504
 505   controlreply(sender, "Server                   Connected for             Accepted        Rejected");
 506
 507   for(sock=tslist;sock;sock=sock->next)
 508     controlreply(sender, "%-20s %20s %10d %15d", sock->authed?sock->authuser:"<not authenticated>", longtoduration(now - sock->connected, 0), sock->accepted, sock->rejected);
 509
 510   controlreply(sender, "-- End of list.");
 511   return CMD_OK;
 512 }
 513
 514 void _init(void) {
 515   sstring *m;
 516   array *accts;
 517   int trustport;
 518
 519   countext = registertgext("count");
 520   if(countext == -1)
 521     return;
 522
 523   m = getconfigitem("trusts_policy", "enforcepolicy");
 524   if(m)
 525     enforcepolicy = atoi(m->content);
 526
 527   m = getconfigitem("trusts_policy", "trustport");
 528   if(m)
 529     trustport = atoi(m->content);
 530   else
 531     trustport = DEFAULT_TRUSTPORT;
 532
 533   if(trustport)
 534     listenerfd = createlistenersock(trustport);
 535
 536   accts = getconfigitems("trusts_policy", "server");
 537   if(!accts) {
 538     Error("trusts_policy", ERR_INFO, "No servers added.");
 539   } else {
 540     sstring **servers = (sstring **)(accts->content);
 541     int i;
 542     for(i=0;i<accts->cursi;i++) {
 543       char server[512];
 544       char *pos;
 545
 546       if(i>=MAXSERVERS) {
 547         Error("trusts_policy", ERR_INFO, "Too many servers specified.");
 548         break;
 549       }
 550
 551       strncpy(server, servers[i]->content, sizeof(server));
 552
 553       pos = strchr(server, ',');
 554
 555       if(!pos) {
 556         Error("trusts_policy", ERR_INFO, "Server line is missing password: %s", server);
 557         continue;
 558       }
 559
 560       *pos = '\0';
 561
 562       trustaccounts[i].used = 1;
 563       strncpy(trustaccounts[i].server, server, SERVERLEN);
 564       strncpy(trustaccounts[i].password, pos+1, TRUSTPASSLEN);
 565     }
 566   }
 567
 568   registerhook(HOOK_TRUSTS_NEWNICK, policycheck_irc);
 569   registerhook(HOOK_TRUSTS_LOSTNICK, policycheck_irc);
 570
 571   registercontrolhelpcmd("trustpolicy", NO_DEVELOPER, 1, trusts_cmdtrustpolicy, "Usage: trustpolicy ?1|0?\nEnables or disables policy enforcement. Shows current status when no parameter is specified.");
 572   registercontrolhelpcmd("trustsockets", NO_DEVELOPER, 0, trusts_cmdtrustsockets, "Usage: trustsockets\nLists all currently active TRUST sockets.");
 573
 574   schedulerecurring(time(NULL)+1, 0, 5, trustdotimeout, NULL);
 575
 576   urandom = fopen("/dev/urandom", "rb");
 577   if(!urandom)
 578     Error("trusts_policy", ERR_ERROR, "Couldn't open /dev/urandom.");
 579 }
 580
 581 void _fini(void) {
 582   trustsocket *sock, *next;
 583
 584   if(countext == -1)
 585     return;
 586
 587   releasetgext(countext);
 588
 589   deregisterhook(HOOK_TRUSTS_NEWNICK, policycheck_irc);
 590   deregisterhook(HOOK_TRUSTS_LOSTNICK, policycheck_irc);
 591
 592   deregistercontrolcmd("trustpolicy", trusts_cmdtrustpolicy);
 593   deregistercontrolcmd("trustsockets", trusts_cmdtrustsockets);
 594
 595   deleteallschedules(trustdotimeout);
 596
 597   if (urandom)
 598     fclose(urandom);
 599
 600   if (listenerfd != -1)
 601     deregisterhandler(listenerfd, 1);
 602
 603   for(sock=tslist;sock;) {
 604     next = sock->next;
 605
 606     trustkillconnection(sock, "Unloading module.");
 607     trustfreeconnection(sock);
 608
 609     sock = next;
 610   }
 611 }