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 1.25.2.2 2006/11/04 21:42:00 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   if (IsServerPort(cptr))
 156     return exit_client(cptr, cptr, &me, "Use a different port");
 157
 158   /*
 159    * parv[0] will be empty for clients connecting for the first time
 160    */
 161   client_name = (*(cli_name(sptr))) ? cli_name(sptr) : "*";
 162
 163   if (parc < 2) {
 164     send_reply(sptr, ERR_NONICKNAMEGIVEN);
 165     return 0;
 166   }
 167
 168   /*
 169    * Don't let them send make us send back a really long string of
 170    * garbage
 171    */
 172   arg = parv[1];
 173   if (strlen(arg) > IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN)))
 174     arg[IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN))] = '\0';
 175
 176   if ((s = strchr(arg, '~')))
 177     *s = '\0';
 178
 179   strcpy(nick, arg);
 180
 181   /*
 182    * If do_nick_name() returns a null name then reject it.
 183    */
 184   if (0 == do_nick_name(nick)) {
 185     send_reply(sptr, ERR_ERRONEUSNICKNAME, arg);
 186     return 0;
 187   }
 188
 189   if (IsRegistered(sptr) && !IsAnOper(sptr) && IsNickGlined(sptr, nick)) {
 190     send_reply(sptr, ERR_ERRONEUSNICKNAME, nick);
 191     return 0;
 192   }
 193
 194   /*
 195    * Check if this is a LOCAL user trying to use a reserved (Juped)
 196    * nick, if so tell him that it's a nick in use...
 197    */
 198   if (isNickJuped(nick)) {
 199     send_reply(sptr, ERR_NICKNAMEINUSE, nick);
 200     return 0;                        /* NICK message ignored */
 201   }
 202
 203   if (!(acptr = FindClient(nick))) {
 204     /*
 205      * No collisions, all clear...
 206      */
 207     return set_nick_name(cptr, sptr, nick, parc, parv);
 208   }
 209   if (IsServer(acptr)) {
 210     send_reply(sptr, ERR_NICKNAMEINUSE, nick);
 211     return 0;                        /* NICK message ignored */
 212   }
 213   /*
 214    * If acptr == sptr, then we have a client doing a nick
 215    * change between *equivalent* nicknames as far as server
 216    * is concerned (user is changing the case of his/her
 217    * nickname or somesuch)
 218    */
 219   if (acptr == sptr) {
 220     /*
 221      * If acptr == sptr, then we have a client doing a nick
 222      * change between *equivalent* nicknames as far as server
 223      * is concerned (user is changing the case of his/her
 224      * nickname or somesuch)
 225      */
 226     if (0 != strcmp(cli_name(acptr), nick)) {
 227       /*
 228        * Allows change of case in his/her nick
 229        */
 230       return set_nick_name(cptr, sptr, nick, parc, parv);
 231     }
 232     /*
 233      * This is just ':old NICK old' type thing.
 234      * Just forget the whole thing here. There is
 235      * no point forwarding it to anywhere,
 236      * especially since servers prior to this
 237      * version would treat it as nick collision.
 238      */
 239     return 0;
 240   }
 241   /*
 242    * Note: From this point forward it can be assumed that
 243    * acptr != sptr (point to different client structures).
 244    */
 245   assert(acptr != sptr);
 246   /*
 247    * If the older one is "non-person", the new entry is just
 248    * allowed to overwrite it. Just silently drop non-person,
 249    * and proceed with the nick. This should take care of the
 250    * "dormant nick" way of generating collisions...
 251    *
 252    * XXX - hmmm can this happen after one is registered?
 253    *
 254    * Yes, client 1 connects to IRC and registers, client 2 connects and
 255    * sends "NICK foo" but doesn't send anything more.  client 1 now does
 256    * /nick foo, they should succeed and client 2 gets disconnected with
 257    * the message below.
 258    */
 259   if (IsUnknown(acptr) && MyConnect(acptr)) {
 260     ServerStats->is_ref++;
 261     IPcheck_connect_fail(acptr);
 262     exit_client(cptr, acptr, &me, "Overridden by other sign on");
 263     return set_nick_name(cptr, sptr, nick, parc, parv);
 264   }
 265   /*
 266    * NICK is coming from local client connection. Just
 267    * send error reply and ignore the command.
 268    */
 269   send_reply(sptr, ERR_NICKNAMEINUSE, nick);
 270   return 0;                        /* NICK message ignored */
 271 }
 272
 273
 274 /*
 275  * ms_nick - server message handler for nicks
 276  * parv[0] = sender prefix
 277  * parv[1] = nickname
 278  *
 279  * If from server, source is client:
 280  *   parv[2] = timestamp
 281  *
 282  * Source is server:
 283  *   parv[2] = hopcount
 284  *   parv[3] = timestamp
 285  *   parv[4] = username
 286  *   parv[5] = hostname
 287  *   parv[6] = umode (optional)
 288  *   parv[parc-3] = IP#                 <- Only Protocol >= 10
 289  *   parv[parc-2] = YXX, numeric nick   <- Only Protocol >= 10
 290  *   parv[parc-1] = info
 291  *   parv[0] = server
 292  */
 293 int ms_nick(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
 294 {
 295   struct Client *acptr;
 296   char nick[NICKLEN + 2];
 297   time_t lastnick = 0;
 298   int differ = 1;
 299   const char *type;
 300
 301   assert(0 != cptr);
 302   assert(0 != sptr);
 303   assert(IsServer(cptr));
 304
 305   if ((IsServer(sptr) && parc < 8) || parc < 3)
 306   {
 307     sendto_opmask_butone(0, SNO_OLDSNO, "bad NICK param count for %s from %C",
 308                          parv[1], cptr);
 309     return need_more_params(sptr, "NICK");
 310   }
 311
 312   ircd_strncpy(nick, parv[1], NICKLEN);
 313   nick[NICKLEN] = '\0';
 314
 315   if (IsServer(sptr))
 316   {
 317     lastnick = atoi(parv[3]);
 318     if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr))
 319       cli_serv(sptr)->lag = TStime() - lastnick;
 320   }
 321   else
 322   {
 323     lastnick = atoi(parv[2]);
 324     if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr))
 325       cli_serv(cli_user(sptr)->server)->lag = TStime() - lastnick;
 326   }
 327   /*
 328    * If do_nick_name() returns a null name OR if the server sent a nick
 329    * name and do_nick_name() changed it in some way (due to rules of nick
 330    * creation) then reject it. If from a server and we reject it,
 331    * and KILL it. -avalon 4/4/92
 332    */
 333   if (!do_nick_name(nick) || strcmp(nick, parv[1]))
 334   {
 335     send_reply(sptr, ERR_ERRONEUSNICKNAME, parv[1]);
 336
 337     ++ServerStats->is_kill;
 338     sendto_opmask_butone(0, SNO_OLDSNO, "Bad Nick: %s From: %s %C", parv[1],
 339                          parv[0], cptr);
 340     sendcmdto_one(&me, CMD_KILL, cptr, "%s :%s (%s <- %s[%s])",
 341                   IsServer(sptr) ? parv[parc - 2] : parv[0], cli_name(&me), parv[1],
 342                   nick, cli_name(cptr));
 343     if (!IsServer(sptr))
 344     {
 345       /*
 346        * bad nick _change_
 347        */
 348       sendcmdto_serv_butone(&me, CMD_KILL, 0, "%s :%s (%s <- %s!%s@%s)",
 349                             parv[0], cli_name(&me), cli_name(cptr), parv[0],
 350                             cli_user(sptr) ? cli_username(sptr) : "",
 351                             cli_user(sptr) ? cli_name(cli_user(sptr)->server) :
 352                             cli_name(cptr));
 353     }
 354     return 0;
 355   }
 356   /* Check against nick name collisions. */
 357   if ((acptr = FindClient(nick)) == NULL)
 358     /* No collisions, all clear... */
 359     return set_nick_name(cptr, sptr, nick, parc, parv);
 360
 361   /*
 362    * If acptr == sptr, then we have a client doing a nick
 363    * change between *equivalent* nicknames as far as server
 364    * is concerned (user is changing the case of his/her
 365    * nickname or somesuch)
 366    */
 367   if (acptr == sptr)
 368   {
 369     if (strcmp(cli_name(acptr), nick) != 0)
 370       /* Allows change of case in his/her nick */
 371       return set_nick_name(cptr, sptr, nick, parc, parv);
 372     else
 373       /* Setting their nick to what it already is? Ignore it. */
 374       return 0;
 375   }
 376   /* now we know we have a real collision. */
 377   /*
 378    * Note: From this point forward it can be assumed that
 379    * acptr != sptr (point to different client structures).
 380    */
 381   assert(acptr != sptr);
 382   /*
 383    * If the older one is "non-person", the new entry is just
 384    * allowed to overwrite it. Just silently drop non-person,
 385    * and proceed with the nick. This should take care of the
 386    * "dormant nick" way of generating collisions...
 387    */
 388   if (IsUnknown(acptr) && MyConnect(acptr))
 389   {
 390     ServerStats->is_ref++;
 391     IPcheck_connect_fail(acptr);
 392     exit_client(cptr, acptr, &me, "Overridden by other sign on");
 393     return set_nick_name(cptr, sptr, nick, parc, parv);
 394   }
 395   /*
 396    * Decide, we really have a nick collision and deal with it
 397    */
 398   /*
 399    * NICK was coming from a server connection.
 400    * This means we have a race condition (two users signing on
 401    * at the same time), or two net fragments reconnecting with the same nick.
 402    * The latter can happen because two different users connected
 403    * or because one and the same user switched server during a net break.
 404    * If the TimeStamps are equal, we kill both (or only 'new'
 405    * if it was a ":server NICK new ...").
 406    * Otherwise we kill the youngest when user@host differ,
 407    * or the oldest when they are the same.
 408    * We treat user and ~user as different, because if it wasn't
 409    * a faked ~user the AUTH wouldn't have added the '~'.
 410    * --Run
 411    *
 412    */
 413   if (IsServer(sptr))
 414   {
 415     struct irc_in_addr ip;
 416     /*
 417      * A new NICK being introduced by a neighbouring
 418      * server (e.g. message type ":server NICK new ..." received)
 419      *
 420      * compare IP address and username
 421      */
 422     base64toip(parv[parc - 3], &ip);
 423     differ =  (0 != memcmp(&cli_ip(acptr), &ip, sizeof(cli_ip(acptr)))) ||
 424               (0 != ircd_strcmp(cli_user(acptr)->username, parv[4]));
 425     sendto_opmask_butone(0, SNO_OLDSNO, "Nick collision on %C (%C %Tu <- "
 426                          "%C %Tu (%s user@host))", acptr, cli_from(acptr),
 427                          cli_lastnick(acptr), cptr, lastnick,
 428                          differ ? "Different" : "Same");
 429   }
 430   else
 431   {
 432     /*
 433      * A NICK change has collided (e.g. message type ":old NICK new").
 434      *
 435      * compare IP address and username
 436      */
 437     differ =  (0 != memcmp(&cli_ip(acptr), &cli_ip(sptr), sizeof(cli_ip(acptr)))) ||
 438               (0 != ircd_strcmp(cli_user(acptr)->username, cli_user(sptr)->username));
 439     sendto_opmask_butone(0, SNO_OLDSNO, "Nick change collision from %C to "
 440                          "%C (%C %Tu <- %C %Tu)", sptr, acptr, cli_from(acptr),
 441                          cli_lastnick(acptr), cptr, lastnick);
 442   }
 443   type = differ ? "overruled by older nick" : "nick collision from same user@host";
 444   /*
 445    * Now remove (kill) the nick on our side if it is the youngest.
 446    * If no timestamp was received, we ignore the incoming nick
 447    * (and expect a KILL for our legit nick soon ):
 448    * When the timestamps are equal we kill both nicks. --Run
 449    * acptr->from != cptr should *always* be true (?).
 450    *
 451    * This exits the client sending the NICK message
 452    */
 453   if ((differ && lastnick >= cli_lastnick(acptr)) ||
 454       (!differ && lastnick <= cli_lastnick(acptr)))
 455   {
 456     ServerStats->is_kill++;
 457     if (!IsServer(sptr))
 458     {
 459       /* If this was a nick change and not a nick introduction, we
 460        * need to ensure that we remove our record of the client, and
 461        * send a KILL to the whole network.
 462        */
 463       assert(!MyConnect(sptr));
 464       /* Inform the rest of the net... */
 465       sendcmdto_serv_butone(&me, CMD_KILL, 0, "%C :%s (%s)",
 466                             sptr, cli_name(&me), type);
 467       /* Don't go sending off a QUIT message... */
 468       SetFlag(sptr, FLAG_KILLED);
 469       /* Remove them locally. */
 470       exit_client_msg(cptr, sptr, &me,
 471                       "Killed (%s (%s))",
 472                       feature_str(FEAT_HIS_SERVERNAME), type);
 473     }
 474     else
 475     {
 476       /* If the origin is a server, this was a new client, so we only
 477        * send the KILL in the direction it came from.  We have no
 478        * client record that we would have to clean up.
 479        */
 480       sendcmdto_one(&me, CMD_KILL, cptr, "%s :%s (%s)",
 481                     parv[parc - 2], cli_name(&me), type);
 482     }
 483     /* If the timestamps differ and we just killed sptr, we don't need to kill
 484      * acptr as well.
 485      */
 486     if (lastnick != cli_lastnick(acptr))
 487       return 0;
 488   }
 489   /* Tell acptr why we are killing it. */
 490   send_reply(acptr, ERR_NICKCOLLISION, nick);
 491
 492   ServerStats->is_kill++;
 493   SetFlag(acptr, FLAG_KILLED);
 494   /*
 495    * This exits the client we had before getting the NICK message
 496    */
 497   sendcmdto_serv_butone(&me, CMD_KILL, NULL, "%C :%s (%s)",
 498                         acptr, feature_str(FEAT_HIS_SERVERNAME),
 499                         type);
 500   exit_client_msg(cptr, acptr, &me, "Killed (%s (%s))",
 501                   feature_str(FEAT_HIS_SERVERNAME), type);
 502   if (lastnick == cli_lastnick(acptr))
 503     return 0;
 504   if (sptr == NULL)
 505     return 0;
 506   return set_nick_name(cptr, sptr, nick, parc, parv);
 507 }