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, char *hint) {
  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 - %s.", trusts_cidr2str(ip, th->nodebits), tg->name->content, nodecount, th->maxpernode, hint);
  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: '%s', %d connected, %d max. - %s.", tg->name->content, tg->count, tg->trustedfor, hint);
 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) - %s.", username, IPtostr(*ip), tg->name->content, hint);
 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 - %s.", username, IPtostr(*ip), tg->name->content, identcount, tg->maxperident, hint);
 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, char *hint) {
 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, hint);
 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), "enforcing with IAuth");
 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     return trustdowrite(sock, "KILL %s %s", sequence_id, message);
 194   }
 195 }
 196
 197 static int trustkillconnection(trustsocket *sock, char *reason) {
 198   trustdowrite(sock, "QUIT %s", reason);
 199   return 0;
 200 }
 201
 202 static void trustfreeconnection(trustsocket *sock) {
 203   trustsocket **pnext = &tslist;
 204
 205   for(trustsocket *ts=tslist;ts;ts=ts->next) {
 206     if(ts == sock) {
 207       deregisterhandler(sock->fd, 1);
 208       *pnext = sock->next;
 209       nsfree(POOL_TRUSTS, sock);
 210       break;
 211     }
 212
 213     pnext = &(sock->next);
 214   }
 215 }
 216
 217 static int handletrustauth(trustsocket *sock, char *server_name, char *mac) {
 218   int i;
 219   char *password = NULL;
 220   unsigned char digest[16];
 221   char noncehexbuf[NONCELEN * 2 + 1];
 222   char hexbuf[sizeof(digest) * 2 + 1];
 223
 224   for(i=0;i<MAXSERVERS;i++) {
 225     if(trustaccounts[i].used && strcmp(trustaccounts[i].server, server_name) == 0) {
 226       password = trustaccounts[i].password;
 227       break;
 228     }
 229   }
 230
 231   if (!password)
 232     return trustkillconnection(sock, "Invalid servername.");
 233
 234   hmacmd5 h;
 235   hmacmd5_init(&h, (unsigned char *)password, strlen(password));
 236   hmacmd5_update(&h, (unsigned char *)hmac_printhex(sock->nonce, noncehexbuf, NONCELEN), NONCELEN * 2);
 237   hmacmd5_final(&h, digest);
 238   if(hmac_strcmp(mac, hmac_printhex(digest, hexbuf, sizeof(digest))))
 239     return trustkillconnection(sock, "Bad MAC.");
 240
 241   sock->authed = 1;
 242   strncpy(sock->authuser, server_name, SERVERLEN);
 243   return trustdowrite(sock, "AUTHOK");
 244 }
 245
 246 #define MAXTOKENS 10
 247 static int handletrustline(trustsocket *sock, char *line) {
 248   char *command, *p, *lastpos;
 249   char *tokens[MAXTOKENS];
 250   int tokensfound = -1;
 251
 252   for(command=lastpos=p=line;*p;p++) {
 253     if(*p == ' ') {
 254       *p = '\0';
 255       if(tokensfound == MAXTOKENS)
 256         return trustkillconnection(sock, "too many tokens");
 257
 258       if(tokensfound >= 0) {
 259         tokens[tokensfound++] = lastpos;
 260       } else {
 261         tokensfound++;
 262       }
 263       lastpos = p + 1;
 264     }
 265   }
 266   if(lastpos != p) {
 267     if(tokensfound == MAXTOKENS)
 268       return trustkillconnection(sock, "too many tokens");
 269     tokens[tokensfound++] = lastpos;
 270   }
 271
 272   if(!sock->authed && !strcmp("AUTH", command)) {
 273     if(tokensfound != 2)
 274       return trustkillconnection(sock, "incorrect arg count for command.");
 275
 276     return handletrustauth(sock, tokens[0], tokens[1]);
 277   } else if(sock->authed && !strcmp("CHECK", command)) {
 278     if(tokensfound != 3)
 279       return trustkillconnection(sock, "incorrect arg count for command.");
 280
 281     policycheck_auth(sock, tokens[0], tokens[1], tokens[2]);
 282     return 1;
 283   } else {
 284     Error("trusts_policy", ERR_WARNING, "Bad command: %s", command);
 285     return 0;
 286   }
 287 }
 288
 289 static trustsocket *findtrustsocketbyfd(int fd) {
 290   for(trustsocket *ts=tslist;ts;ts=ts->next)
 291     if(ts->fd==fd)
 292       return ts;
 293
 294   return NULL;
 295 }
 296
 297 static int handletrustclient(trustsocket *sock) {
 298   int r, remaining = TRUSTBUFSIZE - sock->size, i;
 299   char *lastpos, *c;
 300
 301   if(!remaining) {
 302     trustkillconnection(sock, "Buffer overflow.");
 303     return 0;
 304   }
 305
 306   r = read(sock->fd, sock->buf + sock->size, remaining);
 307   if(r <= 0)
 308     return 0;
 309
 310   sock->size+=r;
 311   lastpos = sock->buf;
 312
 313   for(c=sock->buf,i=0;i<sock->size;i++,c++) {
 314     if(*c != '\n')
 315       continue;
 316     *c = '\0';
 317     if(!handletrustline(sock, lastpos))
 318       return 0;
 319
 320     lastpos = c + 1; /* is this ok? */
 321   }
 322   sock->size-=lastpos - sock->buf;
 323   memmove(sock->buf, lastpos, sock->size);
 324
 325   return 1;
 326 }
 327
 328 static void processtrustclient(int fd, short events) {
 329   trustsocket *sock = findtrustsocketbyfd(fd);
 330
 331   if(!sock)
 332     return;
 333
 334   if(events & POLLIN)
 335     if(!handletrustclient(sock))
 336       trustfreeconnection(sock);
 337 }
 338
 339 static void trustdotimeout(void *arg) {
 340   time_t t = time(NULL);
 341   trustsocket **pnext, *next, *sock;
 342
 343   pnext = &tslist;
 344
 345   for(sock=tslist;sock;) {
 346     next = sock->next;
 347
 348     if(!sock->authed && t >= sock->timeout) {
 349       trustkillconnection(sock, "Auth timeout.");
 350       deregisterhandler(sock->fd, 1);
 351       *pnext = sock->next;
 352       nsfree(POOL_TRUSTS, sock);
 353     } else {
 354       pnext = &(sock->next);
 355     }
 356
 357     sock=next;
 358   }
 359 }
 360
 361 static void processtrustlistener(int fd, short events) {
 362   if(events & POLLIN) {
 363     trustsocket *sock;
 364     char buf[NONCELEN * 2 + 1];
 365
 366     int newfd = accept(fd, NULL, NULL), flags;
 367     if(newfd == -1)
 368       return;
 369
 370     flags = fcntl(newfd, F_GETFL, 0);
 371     if(flags < 0) {
 372       Error("trusts_policy", ERR_WARNING, "Unable to set socket non-blocking.");
 373       close(newfd);
 374       return;
 375     }
 376
 377     if(fcntl(fd, F_SETFL, flags|O_NONBLOCK) < 0) {
 378       Error("trusts_policy", ERR_WARNING, "Unable to set socket non-blocking.");
 379       close(newfd);
 380       return;
 381     }
 382
 383     registerhandler(newfd, POLLIN|POLLERR|POLLHUP, processtrustclient);
 384
 385     sock = nsmalloc(POOL_TRUSTS, sizeof(trustsocket));
 386     if(!sock) {
 387       deregisterhandler(newfd, 1);
 388       return;
 389     }
 390
 391     sock->fd = newfd;
 392     sock->next = tslist;
 393     tslist = sock;
 394
 395     if(fread((char *)sock->nonce, 1, NONCELEN, urandom) != NONCELEN) {
 396       Error("trusts_policy", ERR_WARNING, "Error getting random bytes.");
 397       deregisterhandler(newfd, 1);
 398       tslist = sock->next;
 399       nsfree(POOL_TRUSTS, sock);
 400     } else {
 401       sock->authed = 0;
 402       sock->size = 0;
 403       sock->connected = time(NULL);
 404       sock->timeout = time(NULL) + 30;
 405       sock->accepted = 0;
 406       sock->rejected = 0;
 407       if(!trustdowrite(sock, "AUTH %s", hmac_printhex(sock->nonce, buf, NONCELEN))) {
 408         Error("trusts_policy", ERR_WARNING, "Error writing auth to fd %d.", newfd);
 409         deregisterhandler(newfd, 1);
 410         tslist = sock->next;
 411         nsfree(POOL_TRUSTS, sock);
 412         return;
 413       }
 414     }
 415   }
 416 }
 417
 418 static int createlistenersock(int port) {
 419   struct sockaddr_in s;
 420   int fd;
 421   int optval;
 422
 423   memset(&s, 0, sizeof(struct sockaddr_in));
 424   s.sin_family = AF_INET;
 425   s.sin_addr.s_addr = INADDR_ANY;
 426   s.sin_port = htons(port);
 427
 428   fd = socket(PF_INET, SOCK_STREAM, 0);
 429   if(fd < 0) {
 430     Error("trusts_policy", ERR_WARNING, "Unable to get socket for trustfd.");
 431     return -1;
 432   }
 433
 434   optval = 1;
 435   setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval));
 436
 437   if(bind(fd, (struct sockaddr *)&s, sizeof(struct sockaddr_in)) < 0) {
 438     Error("trusts_policy", ERR_WARNING, "Unable to bind trustfd.");
 439     close(fd);
 440     return -1;
 441   }
 442
 443   if(listen(fd, 5) < 0) {
 444     Error("trusts_policy", ERR_WARNING, "Unable to listen on trustfd.");
 445     close(fd);
 446     return -1;
 447   }
 448
 449   registerhandler(fd, POLLIN, processtrustlistener);
 450
 451   return fd;
 452 }
 453
 454 static void policycheck_irc(int hooknum, void *arg) {
 455   void **args = arg;
 456   nick *np = args[0];
 457   long moving = (long)args[1];
 458   char message[512];
 459   int verdict;
 460   char *hint;
 461
 462   if(moving)
 463     return;
 464
 465   if (enforcepolicy)
 466     hint = "enforcing with glines";
 467   else
 468     hint = "not enforcing";
 469
 470   verdict = checkconnectionth(np->ident, &np->p_nodeaddr, gettrusthost(np), hooknum, 0, message, sizeof(message), hint);
 471
 472   if(!enforcepolicy)
 473     return;
 474
 475   switch (verdict) {
 476     case POLICY_FAILURE_NODECOUNT:
 477       glinebynick(np, POLICY_GLINE_DURATION, message, GLINE_IGNORE_TRUST);
 478       break;
 479     case POLICY_FAILURE_IDENTD:
 480       glinebyip("~*", &np->p_ipaddr, 128, POLICY_GLINE_DURATION, message, GLINE_ALWAYS_USER|GLINE_IGNORE_TRUST);
 481       break;
 482     case POLICY_FAILURE_IDENTCOUNT:
 483       glinebynick(np, POLICY_GLINE_DURATION, message, GLINE_ALWAYS_USER|GLINE_IGNORE_TRUST);
 484       break;
 485   }
 486 }
 487
 488 static int trusts_cmdtrustpolicy(void *source, int cargc, char **cargv) {
 489   nick *sender = source;
 490
 491   if(cargc < 1) {
 492     controlreply(sender, "Trust policy enforcement is currently %s.", enforcepolicy?"enabled":"disabled");
 493     return CMD_OK;
 494   }
 495
 496   enforcepolicy = atoi(cargv[0]);
 497   controlwall(NO_OPER, NL_TRUSTS, "%s %s trust policy enforcement.", controlid(sender), enforcepolicy?"enabled":"disabled");
 498   controlreply(sender, "Trust policy enforcement is now %s.", enforcepolicy?"enabled":"disabled");
 499
 500   return CMD_OK;
 501 }
 502
 503 static int trusts_cmdtrustsockets(void *source, int cargc, char **cargv) {
 504   nick *sender = source;
 505   time_t now;
 506   trustsocket *sock;
 507
 508   time(&now);
 509
 510   controlreply(sender, "Server                   Connected for             Accepted        Rejected");
 511
 512   for(sock=tslist;sock;sock=sock->next)
 513     controlreply(sender, "%-20s %20s %10d %15d", sock->authed?sock->authuser:"<not authenticated>", longtoduration(now - sock->connected, 0), sock->accepted, sock->rejected);
 514
 515   controlreply(sender, "-- End of list.");
 516   return CMD_OK;
 517 }
 518
 519 void _init(void) {
 520   sstring *m;
 521   array *accts;
 522   int trustport;
 523
 524   countext = registertgext("count");
 525   if(countext == -1)
 526     return;
 527
 528   m = getconfigitem("trusts_policy", "enforcepolicy");
 529   if(m)
 530     enforcepolicy = atoi(m->content);
 531
 532   m = getconfigitem("trusts_policy", "trustport");
 533   if(m)
 534     trustport = atoi(m->content);
 535   else
 536     trustport = DEFAULT_TRUSTPORT;
 537
 538   if(trustport)
 539     listenerfd = createlistenersock(trustport);
 540
 541   accts = getconfigitems("trusts_policy", "server");
 542   if(!accts) {
 543     Error("trusts_policy", ERR_INFO, "No servers added.");
 544   } else {
 545     sstring **servers = (sstring **)(accts->content);
 546     int i;
 547     for(i=0;i<accts->cursi;i++) {
 548       char server[512];
 549       char *pos;
 550
 551       if(i>=MAXSERVERS) {
 552         Error("trusts_policy", ERR_INFO, "Too many servers specified.");
 553         break;
 554       }
 555
 556       strncpy(server, servers[i]->content, sizeof(server));
 557
 558       pos = strchr(server, ',');
 559
 560       if(!pos) {
 561         Error("trusts_policy", ERR_INFO, "Server line is missing password: %s", server);
 562         continue;
 563       }
 564
 565       *pos = '\0';
 566
 567       trustaccounts[i].used = 1;
 568       strncpy(trustaccounts[i].server, server, SERVERLEN);
 569       strncpy(trustaccounts[i].password, pos+1, TRUSTPASSLEN);
 570     }
 571   }
 572
 573   registerhook(HOOK_TRUSTS_NEWNICK, policycheck_irc);
 574   registerhook(HOOK_TRUSTS_LOSTNICK, policycheck_irc);
 575
 576   registercontrolhelpcmd("trustpolicy", NO_DEVELOPER, 1, trusts_cmdtrustpolicy, "Usage: trustpolicy ?1|0?\nEnables or disables policy enforcement. Shows current status when no parameter is specified.");
 577   registercontrolhelpcmd("trustsockets", NO_DEVELOPER, 0, trusts_cmdtrustsockets, "Usage: trustsockets\nLists all currently active TRUST sockets.");
 578
 579   schedulerecurring(time(NULL)+1, 0, 5, trustdotimeout, NULL);
 580
 581   urandom = fopen("/dev/urandom", "rb");
 582   if(!urandom)
 583     Error("trusts_policy", ERR_ERROR, "Couldn't open /dev/urandom.");
 584 }
 585
 586 void _fini(void) {
 587   trustsocket *sock, *next;
 588
 589   if(countext == -1)
 590     return;
 591
 592   releasetgext(countext);
 593
 594   deregisterhook(HOOK_TRUSTS_NEWNICK, policycheck_irc);
 595   deregisterhook(HOOK_TRUSTS_LOSTNICK, policycheck_irc);
 596
 597   deregistercontrolcmd("trustpolicy", trusts_cmdtrustpolicy);
 598   deregistercontrolcmd("trustsockets", trusts_cmdtrustsockets);
 599
 600   deleteallschedules(trustdotimeout);
 601
 602   if (urandom)
 603     fclose(urandom);
 604
 605   if (listenerfd != -1)
 606     deregisterhandler(listenerfd, 1);
 607
 608   for(sock=tslist;sock;) {
 609     next = sock->next;
 610
 611     trustkillconnection(sock, "Unloading module.");
 612     trustfreeconnection(sock);
 613
 614     sock = next;
 615   }
 616 }