ircd/m_nick.c

   1 /*
   2  * IRC - Internet Relay Chat, ircd/m_nick.c
   3  * Copyright (C) 1990 Jarkko Oikarinen and
   4  *                    University of Oulu, Computing Center
   5  *
   6  * See file AUTHORS in IRC package for additional names of
   7  * the programmers.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 1, or (at your option)
  12  * any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  * $Id: m_nick.c,v 1.25.2.1 2005/11/16 04:18:47 entrope Exp $
  24  */
  25
  26 /*
  27  * m_functions execute protocol messages on this server:
  28  *
  29  *    cptr    is always NON-NULL, pointing to a *LOCAL* client
  30  *            structure (with an open socket connected!). This
  31  *            identifies the physical socket where the message
  32  *            originated (or which caused the m_function to be
  33  *            executed--some m_functions may call others...).
  34  *
  35  *    sptr    is the source of the message, defined by the
  36  *            prefix part of the message if present. If not
  37  *            or prefix not found, then sptr==cptr.
  38  *
  39  *            (!IsServer(cptr)) => (cptr == sptr), because
  40  *            prefixes are taken *only* from servers...
  41  *
  42  *            (IsServer(cptr))
  43  *                    (sptr == cptr) => the message didn't
  44  *                    have the prefix.
  45  *
  46  *                    (sptr != cptr && IsServer(sptr) means
  47  *                    the prefix specified servername. (?)
  48  *
  49  *                    (sptr != cptr && !IsServer(sptr) means
  50  *                    that message originated from a remote
  51  *                    user (not local).
  52  *
  53  *            combining
  54  *
  55  *            (!IsServer(sptr)) means that, sptr can safely
  56  *            taken as defining the target structure of the
  57  *            message in this server.
  58  *
  59  *    *Always* true (if 'parse' and others are working correct):
  60  *
  61  *    1)      sptr->from == cptr  (note: cptr->from == cptr)
  62  *
  63  *    2)      MyConnect(sptr) <=> sptr == cptr (e.g. sptr
  64  *            *cannot* be a local connection, unless it's
  65  *            actually cptr!). [MyConnect(x) should probably
  66  *            be defined as (x == x->from) --msa ]
  67  *
  68  *    parc    number of variable parameter strings (if zero,
  69  *            parv is allowed to be NULL)
  70  *
  71  *    parv    a NULL terminated list of parameter pointers,
  72  *
  73  *                    parv[0], sender (prefix string), if not present
  74  *                            this points to an empty string.
  75  *                    parv[1]...parv[parc-1]
  76  *                            pointers to additional parameters
  77  *                    parv[parc] == NULL, *always*
  78  *
  79  *            note:   it is guaranteed that parv[0]..parv[parc-1] are all
  80  *                    non-NULL pointers.
  81  */
  82 #include "config.h"
  83
  84 #include "IPcheck.h"
  85 #include "client.h"
  86 #include "hash.h"
  87 #include "ircd.h"
  88 #include "ircd_chattr.h"
  89 #include "ircd_features.h"
  90 #include "ircd_log.h"
  91 #include "ircd_reply.h"
  92 #include "ircd_string.h"
  93 #include "msg.h"
  94 #include "numeric.h"
  95 #include "numnicks.h"
  96 #include "s_debug.h"
  97 #include "s_misc.h"
  98 #include "s_user.h"
  99 #include "send.h"
 100 #include "sys.h"
 101 #include "gline.h"
 102
 103 /* #include <assert.h> -- Now using assert in ircd_log.h */
 104 #include <stdlib.h>
 105 #include <string.h>
 106
 107  /*
 108 * 'do_nick_name' ensures that the given parameter (nick) is really a proper
 109 * string for a nickname (note, the 'nick' may be modified in the process...)
 110 *
 111 * RETURNS the length of the final NICKNAME (0, if nickname is invalid)
 112 *
 113 * Nickname characters are in range 'A'..'}', '_', '-', '0'..'9'
 114 *  anything outside the above set will terminate nickname.
 115 * In addition, the first character cannot be '-' or a Digit.
 116 *
 117 * Note:
 118 *  The '~'-character should be allowed, but a change should be global,
 119 *  some confusion would result if only few servers allowed it...
 120 */
 121 static int do_nick_name(char* nick)
 122 {
 123   char* ch  = nick;
 124   char* end = ch + NICKLEN;
 125   assert(0 != ch);
 126
 127   /* first character in [0..9-] */
 128   if (*ch == '-' || IsDigit(*ch))
 129     return 0;
 130   for ( ; (ch < end) && *ch; ++ch)
 131     if (!IsNickChar(*ch))
 132       break;
 133
 134   *ch = '\0';
 135
 136   return (ch - nick);
 137 }
 138
 139 /*
 140  * m_nick - message handler for local clients
 141  * parv[0] = sender prefix
 142  * parv[1] = nickname
 143  */
 144 int m_nick(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
 145 {
 146   struct Client* acptr;
 147   char           nick[NICKLEN + 2];
 148   char*          arg;
 149   char*          s;
 150   const char*    client_name;
 151
 152   assert(0 != cptr);
 153   assert(cptr == sptr);
 154
 155   /*
 156    * parv[0] will be empty for clients connecting for the first time
 157    */
 158   client_name = (*(cli_name(sptr))) ? cli_name(sptr) : "*";
 159
 160   if (parc < 2) {
 161     send_reply(sptr, ERR_NONICKNAMEGIVEN);
 162     return 0;
 163   }
 164   /*
 165    * Don't let them send make us send back a really long string of
 166    * garbage
 167    */
 168   arg = parv[1];
 169   if (strlen(arg) > IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN)))
 170     arg[IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN))] = '\0';
 171
 172   if ((s = strchr(arg, '~')))
 173     *s = '\0';
 174
 175   strcpy(nick, arg);
 176
 177   /*
 178    * If do_nick_name() returns a null name then reject it.
 179    */
 180   if (0 == do_nick_name(nick)) {
 181     send_reply(sptr, ERR_ERRONEUSNICKNAME, arg);
 182     return 0;
 183   }
 184
 185   if (IsRegistered(sptr) && !IsAnOper(sptr) && IsNickGlined(sptr, nick)) {
 186     send_reply(sptr, ERR_ERRONEUSNICKNAME, nick);
 187     return 0;
 188   }
 189
 190   /*
 191    * Check if this is a LOCAL user trying to use a reserved (Juped)
 192    * nick, if so tell him that it's a nick in use...
 193    */
 194   if (isNickJuped(nick)) {
 195     send_reply(sptr, ERR_NICKNAMEINUSE, nick);
 196     return 0;                        /* NICK message ignored */
 197   }
 198
 199   if (!(acptr = FindClient(nick))) {
 200     /*
 201      * No collisions, all clear...
 202      */
 203     return set_nick_name(cptr, sptr, nick, parc, parv);
 204   }
 205   if (IsServer(acptr)) {
 206     send_reply(sptr, ERR_NICKNAMEINUSE, nick);
 207     return 0;                        /* NICK message ignored */
 208   }
 209   /*
 210    * If acptr == sptr, then we have a client doing a nick
 211    * change between *equivalent* nicknames as far as server
 212    * is concerned (user is changing the case of his/her
 213    * nickname or somesuch)
 214    */
 215   if (acptr == sptr) {
 216     /*
 217      * If acptr == sptr, then we have a client doing a nick
 218      * change between *equivalent* nicknames as far as server
 219      * is concerned (user is changing the case of his/her
 220      * nickname or somesuch)
 221      */
 222     if (0 != strcmp(cli_name(acptr), nick)) {
 223       /*
 224        * Allows change of case in his/her nick
 225        */
 226       return set_nick_name(cptr, sptr, nick, parc, parv);
 227     }
 228     /*
 229      * This is just ':old NICK old' type thing.
 230      * Just forget the whole thing here. There is
 231      * no point forwarding it to anywhere,
 232      * especially since servers prior to this
 233      * version would treat it as nick collision.
 234      */
 235     return 0;
 236   }
 237   /*
 238    * Note: From this point forward it can be assumed that
 239    * acptr != sptr (point to different client structures).
 240    */
 241   assert(acptr != sptr);
 242   /*
 243    * If the older one is "non-person", the new entry is just
 244    * allowed to overwrite it. Just silently drop non-person,
 245    * and proceed with the nick. This should take care of the
 246    * "dormant nick" way of generating collisions...
 247    *
 248    * XXX - hmmm can this happen after one is registered?
 249    *
 250    * Yes, client 1 connects to IRC and registers, client 2 connects and
 251    * sends "NICK foo" but doesn't send anything more.  client 1 now does
 252    * /nick foo, they should succeed and client 2 gets disconnected with
 253    * the message below.
 254    */
 255   if (IsUnknown(acptr) && MyConnect(acptr)) {
 256     ServerStats->is_ref++;
 257     IPcheck_connect_fail(acptr);
 258     exit_client(cptr, acptr, &me, "Overridden by other sign on");
 259     return set_nick_name(cptr, sptr, nick, parc, parv);
 260   }
 261   /*
 262    * NICK is coming from local client connection. Just
 263    * send error reply and ignore the command.
 264    */
 265   send_reply(sptr, ERR_NICKNAMEINUSE, nick);
 266   return 0;                        /* NICK message ignored */
 267 }
 268
 269
 270 /*
 271  * ms_nick - server message handler for nicks
 272  * parv[0] = sender prefix
 273  * parv[1] = nickname
 274  *
 275  * If from server, source is client:
 276  *   parv[2] = timestamp
 277  *
 278  * Source is server:
 279  *   parv[2] = hopcount
 280  *   parv[3] = timestamp
 281  *   parv[4] = username
 282  *   parv[5] = hostname
 283  *   parv[6] = umode (optional)
 284  *   parv[parc-3] = IP#                 <- Only Protocol >= 10
 285  *   parv[parc-2] = YXX, numeric nick   <- Only Protocol >= 10
 286  *   parv[parc-1] = info
 287  *   parv[0] = server
 288  */
 289 int ms_nick(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
 290 {
 291   struct Client *acptr;
 292   char nick[NICKLEN + 2];
 293   time_t lastnick = 0;
 294   int differ = 1;
 295   const char *type;
 296
 297   assert(0 != cptr);
 298   assert(0 != sptr);
 299   assert(IsServer(cptr));
 300
 301   if ((IsServer(sptr) && parc < 8) || parc < 3)
 302   {
 303     sendto_opmask_butone(0, SNO_OLDSNO, "bad NICK param count for %s from %C",
 304                          parv[1], cptr);
 305     return need_more_params(sptr, "NICK");
 306   }
 307
 308   ircd_strncpy(nick, parv[1], NICKLEN);
 309   nick[NICKLEN] = '\0';
 310
 311   if (IsServer(sptr))
 312   {
 313     lastnick = atoi(parv[3]);
 314     if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr))
 315       cli_serv(sptr)->lag = TStime() - lastnick;
 316   }
 317   else
 318   {
 319     lastnick = atoi(parv[2]);
 320     if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr))
 321       cli_serv(cli_user(sptr)->server)->lag = TStime() - lastnick;
 322   }
 323   /*
 324    * If do_nick_name() returns a null name OR if the server sent a nick
 325    * name and do_nick_name() changed it in some way (due to rules of nick
 326    * creation) then reject it. If from a server and we reject it,
 327    * and KILL it. -avalon 4/4/92
 328    */
 329   if (!do_nick_name(nick) || strcmp(nick, parv[1]))
 330   {
 331     send_reply(sptr, ERR_ERRONEUSNICKNAME, parv[1]);
 332
 333     ++ServerStats->is_kill;
 334     sendto_opmask_butone(0, SNO_OLDSNO, "Bad Nick: %s From: %s %C", parv[1],
 335                          parv[0], cptr);
 336     sendcmdto_one(&me, CMD_KILL, cptr, "%s :%s (%s <- %s[%s])",
 337                   IsServer(sptr) ? parv[parc - 2] : parv[0], cli_name(&me), parv[1],
 338                   nick, cli_name(cptr));
 339     if (!IsServer(sptr))
 340     {
 341       /*
 342        * bad nick _change_
 343        */
 344       sendcmdto_serv_butone(&me, CMD_KILL, 0, "%s :%s (%s <- %s!%s@%s)",
 345                             parv[0], cli_name(&me), cli_name(cptr), parv[0],
 346                             cli_user(sptr) ? cli_username(sptr) : "",
 347                             cli_user(sptr) ? cli_name(cli_user(sptr)->server) :
 348                             cli_name(cptr));
 349     }
 350     return 0;
 351   }
 352   /* Check against nick name collisions. */
 353   if ((acptr = FindClient(nick)) == NULL)
 354     /* No collisions, all clear... */
 355     return set_nick_name(cptr, sptr, nick, parc, parv);
 356
 357   /*
 358    * If acptr == sptr, then we have a client doing a nick
 359    * change between *equivalent* nicknames as far as server
 360    * is concerned (user is changing the case of his/her
 361    * nickname or somesuch)
 362    */
 363   if (acptr == sptr)
 364   {
 365     if (strcmp(cli_name(acptr), nick) != 0)
 366       /* Allows change of case in his/her nick */
 367       return set_nick_name(cptr, sptr, nick, parc, parv);
 368     else
 369       /* Setting their nick to what it already is? Ignore it. */
 370       return 0;
 371   }
 372   /* now we know we have a real collision. */
 373   /*
 374    * Note: From this point forward it can be assumed that
 375    * acptr != sptr (point to different client structures).
 376    */
 377   assert(acptr != sptr);
 378   /*
 379    * If the older one is "non-person", the new entry is just
 380    * allowed to overwrite it. Just silently drop non-person,
 381    * and proceed with the nick. This should take care of the
 382    * "dormant nick" way of generating collisions...
 383    */
 384   if (IsUnknown(acptr) && MyConnect(acptr))
 385   {
 386     ServerStats->is_ref++;
 387     IPcheck_connect_fail(acptr);
 388     exit_client(cptr, acptr, &me, "Overridden by other sign on");
 389     return set_nick_name(cptr, sptr, nick, parc, parv);
 390   }
 391   /*
 392    * Decide, we really have a nick collision and deal with it
 393    */
 394   /*
 395    * NICK was coming from a server connection.
 396    * This means we have a race condition (two users signing on
 397    * at the same time), or two net fragments reconnecting with the same nick.
 398    * The latter can happen because two different users connected
 399    * or because one and the same user switched server during a net break.
 400    * If the TimeStamps are equal, we kill both (or only 'new'
 401    * if it was a ":server NICK new ...").
 402    * Otherwise we kill the youngest when user@host differ,
 403    * or the oldest when they are the same.
 404    * We treat user and ~user as different, because if it wasn't
 405    * a faked ~user the AUTH wouldn't have added the '~'.
 406    * --Run
 407    *
 408    */
 409   if (IsServer(sptr))
 410   {
 411     struct irc_in_addr ip;
 412     /*
 413      * A new NICK being introduced by a neighbouring
 414      * server (e.g. message type ":server NICK new ..." received)
 415      *
 416      * compare IP address and username
 417      */
 418     base64toip(parv[parc - 3], &ip);
 419     differ =  (0 != memcmp(&cli_ip(acptr), &ip, sizeof(cli_ip(acptr)))) ||
 420               (0 != ircd_strcmp(cli_user(acptr)->username, parv[4]));
 421     sendto_opmask_butone(0, SNO_OLDSNO, "Nick collision on %C (%C %Tu <- "
 422                          "%C %Tu (%s user@host))", acptr, cli_from(acptr),
 423                          cli_lastnick(acptr), cptr, lastnick,
 424                          differ ? "Different" : "Same");
 425   }
 426   else
 427   {
 428     /*
 429      * A NICK change has collided (e.g. message type ":old NICK new").
 430      *
 431      * compare IP address and username
 432      */
 433     differ =  (0 != memcmp(&cli_ip(acptr), &cli_ip(sptr), sizeof(cli_ip(acptr)))) ||
 434               (0 != ircd_strcmp(cli_user(acptr)->username, cli_user(sptr)->username));
 435     sendto_opmask_butone(0, SNO_OLDSNO, "Nick change collision from %C to "
 436                          "%C (%C %Tu <- %C %Tu)", sptr, acptr, cli_from(acptr),
 437                          cli_lastnick(acptr), cptr, lastnick);
 438   }
 439   type = differ ? "overruled by older nick" : "nick collision from same user@host";
 440   /*
 441    * Now remove (kill) the nick on our side if it is the youngest.
 442    * If no timestamp was received, we ignore the incoming nick
 443    * (and expect a KILL for our legit nick soon ):
 444    * When the timestamps are equal we kill both nicks. --Run
 445    * acptr->from != cptr should *always* be true (?).
 446    *
 447    * This exits the client sending the NICK message
 448    */
 449   if ((differ && lastnick >= cli_lastnick(acptr)) ||
 450       (!differ && lastnick <= cli_lastnick(acptr)))
 451   {
 452     ServerStats->is_kill++;
 453     if (!IsServer(sptr))
 454     {
 455       /* If this was a nick change and not a nick introduction, we
 456        * need to ensure that we remove our record of the client, and
 457        * send a KILL to the whole network.
 458        */
 459       assert(!MyConnect(sptr));
 460       /* Inform the rest of the net... */
 461       sendcmdto_serv_butone(&me, CMD_KILL, 0, "%C :%s (%s)",
 462                             sptr, cli_name(&me), type);
 463       /* Don't go sending off a QUIT message... */
 464       SetFlag(sptr, FLAG_KILLED);
 465       /* Remove them locally. */
 466       exit_client_msg(cptr, sptr, &me,
 467                       "Killed (%s (%s))",
 468                       feature_str(FEAT_HIS_SERVERNAME), type);
 469     }
 470     else
 471     {
 472       /* If the origin is a server, this was a new client, so we only
 473        * send the KILL in the direction it came from.  We have no
 474        * client record that we would have to clean up.
 475        */
 476       sendcmdto_one(&me, CMD_KILL, cptr, "%s :%s (%s)",
 477                     parv[parc - 2], cli_name(&me), type);
 478     }
 479     /* If the timestamps differ and we just killed sptr, we don't need to kill
 480      * acptr as well.
 481      */
 482     if (lastnick != cli_lastnick(acptr))
 483       return 0;
 484   }
 485   /* Tell acptr why we are killing it. */
 486   send_reply(acptr, ERR_NICKCOLLISION, nick);
 487
 488   ServerStats->is_kill++;
 489   SetFlag(acptr, FLAG_KILLED);
 490   /*
 491    * This exits the client we had before getting the NICK message
 492    */
 493   sendcmdto_serv_butone(&me, CMD_KILL, NULL, "%C :%s (%s)",
 494                         acptr, feature_str(FEAT_HIS_SERVERNAME),
 495                         type);
 496   exit_client_msg(cptr, acptr, &me, "Killed (%s (%s))",
 497                   feature_str(FEAT_HIS_SERVERNAME), type);
 498   if (lastnick == cli_lastnick(acptr))
 499     return 0;
 500   if (sptr == NULL)
 501     return 0;
 502   return set_nick_name(cptr, sptr, nick, parc, parv);
 503 }