src/modules/extra/m_ldapauth.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2011 Pierre Carrier <pierre@spotify.com>
   5  *   Copyright (C) 2009-2010 Robin Burchell <robin+git@viroteck.net>
   6  *   Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
   7  *   Copyright (C) 2008 Pippijn van Steenhoven <pip88nl@gmail.com>
   8  *   Copyright (C) 2008 Craig Edwards <craigedwards@brainbox.cc>
   9  *   Copyright (C) 2008 Dennis Friis <peavey@inspircd.org>
  10  *   Copyright (C) 2007 Carsten Valdemar Munk <carsten.munk+inspircd@gmail.com>
  11  *
  12  * This file is part of InspIRCd.  InspIRCd is free software: you can
  13  * redistribute it and/or modify it under the terms of the GNU General Public
  14  * License as published by the Free Software Foundation, version 2.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  19  * details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24
  25
  26 #include "inspircd.h"
  27 #include "users.h"
  28 #include "channels.h"
  29 #include "modules.h"
  30
  31 #include <ldap.h>
  32
  33 #ifdef _WIN32
  34 # pragma comment(lib, "ldap.lib")
  35 # pragma comment(lib, "lber.lib")
  36 #endif
  37
  38 /* $ModDesc: Allow/Deny connections based upon answer from LDAP server */
  39 /* $LinkerFlags: -lldap */
  40
  41 class ModuleLDAPAuth : public Module
  42 {
  43         LocalIntExt ldapAuthed;
  44         LocalStringExt ldapVhost;
  45         std::string base;
  46         std::string attribute;
  47         std::string ldapserver;
  48         std::string allowpattern;
  49         std::string killreason;
  50         std::string username;
  51         std::string password;
  52         std::string vhost;
  53         std::vector<std::string> whitelistedcidrs;
  54         std::vector<std::pair<std::string, std::string> > requiredattributes;
  55         int searchscope;
  56         bool verbose;
  57         bool useusername;
  58         LDAP *conn;
  59
  60 public:
  61         ModuleLDAPAuth()
  62                 : ldapAuthed("ldapauth", this)
  63                 , ldapVhost("ldapauth_vhost", this)
  64         {
  65                 conn = NULL;
  66         }
  67
  68         void init()
  69         {
  70                 Implementation eventlist[] = { I_OnCheckReady, I_OnRehash,I_OnUserRegister, I_OnUserConnect };
  71                 ServerInstance->Modules->Attach(eventlist, this, 4);
  72                 OnRehash(NULL);
  73         }
  74
  75         ~ModuleLDAPAuth()
  76         {
  77                 if (conn)
  78                         ldap_unbind_ext(conn, NULL, NULL);
  79         }
  80
  81         void OnRehash(User* user)
  82         {
  83                 ConfigTag* tag = ServerInstance->Config->ConfValue("ldapauth");
  84                 whitelistedcidrs.clear();
  85                 requiredattributes.clear();
  86
  87                 base                    = tag->getString("baserdn");
  88                 attribute               = tag->getString("attribute");
  89                 ldapserver              = tag->getString("server");
  90                 allowpattern    = tag->getString("allowpattern");
  91                 killreason              = tag->getString("killreason");
  92                 std::string scope       = tag->getString("searchscope");
  93                 username                = tag->getString("binddn");
  94                 password                = tag->getString("bindauth");
  95                 vhost                   = tag->getString("host");
  96                 verbose                 = tag->getBool("verbose");              /* Set to true if failed connects should be reported to operators */
  97                 useusername             = tag->getBool("userfield");
  98
  99                 ConfigTagList whitelisttags = ServerInstance->Config->ConfTags("ldapwhitelist");
 100
 101                 for (ConfigIter i = whitelisttags.first; i != whitelisttags.second; ++i)
 102                 {
 103                         std::string cidr = i->second->getString("cidr");
 104                         if (!cidr.empty()) {
 105                                 whitelistedcidrs.push_back(cidr);
 106                         }
 107                 }
 108
 109                 ConfigTagList attributetags = ServerInstance->Config->ConfTags("ldaprequire");
 110
 111                 for (ConfigIter i = attributetags.first; i != attributetags.second; ++i)
 112                 {
 113                         const std::string attr = i->second->getString("attribute");
 114                         const std::string val = i->second->getString("value");
 115
 116                         if (!attr.empty() && !val.empty())
 117                                 requiredattributes.push_back(make_pair(attr, val));
 118                 }
 119
 120                 if (scope == "base")
 121                         searchscope = LDAP_SCOPE_BASE;
 122                 else if (scope == "onelevel")
 123                         searchscope = LDAP_SCOPE_ONELEVEL;
 124                 else searchscope = LDAP_SCOPE_SUBTREE;
 125
 126                 Connect();
 127         }
 128
 129         bool Connect()
 130         {
 131                 if (conn != NULL)
 132                         ldap_unbind_ext(conn, NULL, NULL);
 133                 int res, v = LDAP_VERSION3;
 134                 res = ldap_initialize(&conn, ldapserver.c_str());
 135                 if (res != LDAP_SUCCESS)
 136                 {
 137                         if (verbose)
 138                                 ServerInstance->SNO->WriteToSnoMask('c', "LDAP connection failed: %s", ldap_err2string(res));
 139                         conn = NULL;
 140                         return false;
 141                 }
 142
 143                 res = ldap_set_option(conn, LDAP_OPT_PROTOCOL_VERSION, (void *)&v);
 144                 if (res != LDAP_SUCCESS)
 145                 {
 146                         if (verbose)
 147                                 ServerInstance->SNO->WriteToSnoMask('c', "LDAP set protocol to v3 failed: %s", ldap_err2string(res));
 148                         ldap_unbind_ext(conn, NULL, NULL);
 149                         conn = NULL;
 150                         return false;
 151                 }
 152                 return true;
 153         }
 154
 155         std::string SafeReplace(const std::string &text, std::map<std::string,
 156                         std::string> &replacements)
 157         {
 158                 std::string result;
 159                 result.reserve(MAXBUF);
 160
 161                 for (unsigned int i = 0; i < text.length(); ++i) {
 162                         char c = text[i];
 163                         if (c == '$') {
 164                                 // find the first nonalpha
 165                                 i++;
 166                                 unsigned int start = i;
 167
 168                                 while (i < text.length() - 1 && isalpha(text[i + 1]))
 169                                         ++i;
 170
 171                                 std::string key = text.substr(start, (i - start) + 1);
 172                                 result.append(replacements[key]);
 173                         } else {
 174                                 result.push_back(c);
 175                         }
 176                 }
 177
 178            return result;
 179         }
 180
 181         virtual void OnUserConnect(LocalUser *user)
 182         {
 183                 std::string* cc = ldapVhost.get(user);
 184                 if (cc)
 185                 {
 186                         user->ChangeDisplayedHost(cc->c_str());
 187                         ldapVhost.unset(user);
 188                 }
 189         }
 190
 191         ModResult OnUserRegister(LocalUser* user)
 192         {
 193                 if ((!allowpattern.empty()) && (InspIRCd::Match(user->nick,allowpattern)))
 194                 {
 195                         ldapAuthed.set(user,1);
 196                         return MOD_RES_PASSTHRU;
 197                 }
 198
 199                 for (std::vector<std::string>::iterator i = whitelistedcidrs.begin(); i != whitelistedcidrs.end(); i++)
 200                 {
 201                         if (InspIRCd::MatchCIDR(user->GetIPString(), *i, ascii_case_insensitive_map))
 202                         {
 203                                 ldapAuthed.set(user,1);
 204                                 return MOD_RES_PASSTHRU;
 205                         }
 206                 }
 207
 208                 if (!CheckCredentials(user))
 209                 {
 210                         ServerInstance->Users->QuitUser(user, killreason);
 211                         return MOD_RES_DENY;
 212                 }
 213                 return MOD_RES_PASSTHRU;
 214         }
 215
 216         bool CheckCredentials(LocalUser* user)
 217         {
 218                 if (conn == NULL)
 219                         if (!Connect())
 220                                 return false;
 221
 222                 if (user->password.empty())
 223                 {
 224                         if (verbose)
 225                                 ServerInstance->SNO->WriteToSnoMask('c', "Forbidden connection from %s (No password provided)", user->GetFullRealHost().c_str());
 226                         return false;
 227                 }
 228
 229                 int res;
 230                 // bind anonymously if no bind DN and authentication are given in the config
 231                 struct berval cred;
 232                 cred.bv_val = const_cast<char*>(password.c_str());
 233                 cred.bv_len = password.length();
 234
 235                 if ((res = ldap_sasl_bind_s(conn, username.c_str(), LDAP_SASL_SIMPLE, &cred, NULL, NULL, NULL)) != LDAP_SUCCESS)
 236                 {
 237                         if (res == LDAP_SERVER_DOWN)
 238                         {
 239                                 // Attempt to reconnect if the connection dropped
 240                                 if (verbose)
 241                                         ServerInstance->SNO->WriteToSnoMask('a', "LDAP server has gone away - reconnecting...");
 242                                 Connect();
 243                                 res = ldap_sasl_bind_s(conn, username.c_str(), LDAP_SASL_SIMPLE, &cred, NULL, NULL, NULL);
 244                         }
 245
 246                         if (res != LDAP_SUCCESS)
 247                         {
 248                                 if (verbose)
 249                                         ServerInstance->SNO->WriteToSnoMask('c', "Forbidden connection from %s (LDAP bind failed: %s)", user->GetFullRealHost().c_str(), ldap_err2string(res));
 250                                 ldap_unbind_ext(conn, NULL, NULL);
 251                                 conn = NULL;
 252                                 return false;
 253                         }
 254                 }
 255
 256                 LDAPMessage *msg, *entry;
 257                 std::string what = (attribute + "=" + (useusername ? user->ident : user->nick));
 258                 if ((res = ldap_search_ext_s(conn, base.c_str(), searchscope, what.c_str(), NULL, 0, NULL, NULL, NULL, 0, &msg)) != LDAP_SUCCESS)
 259                 {
 260                         // Do a second search, based on password, if it contains a :
 261                         // That is, PASS <user>:<password> will work.
 262                         size_t pos = user->password.find(":");
 263                         if (pos != std::string::npos)
 264                         {
 265                                 std::string cutpassword = user->password.substr(0, pos);
 266                                 res = ldap_search_ext_s(conn, base.c_str(), searchscope, cutpassword.c_str(), NULL, 0, NULL, NULL, NULL, 0, &msg);
 267
 268                                 if (res == LDAP_SUCCESS)
 269                                 {
 270                                         // Trim the user: prefix, leaving just 'pass' for later password check
 271                                         user->password = user->password.substr(pos + 1);
 272                                 }
 273                         }
 274
 275                         // It may have found based on user:pass check above.
 276                         if (res != LDAP_SUCCESS)
 277                         {
 278                                 if (verbose)
 279                                         ServerInstance->SNO->WriteToSnoMask('c', "Forbidden connection from %s (LDAP search failed: %s)", user->GetFullRealHost().c_str(), ldap_err2string(res));
 280                                 return false;
 281                         }
 282                 }
 283                 if (ldap_count_entries(conn, msg) > 1)
 284                 {
 285                         if (verbose)
 286                                 ServerInstance->SNO->WriteToSnoMask('c', "Forbidden connection from %s (LDAP search returned more than one result: %s)", user->GetFullRealHost().c_str(), ldap_err2string(res));
 287                         ldap_msgfree(msg);
 288                         return false;
 289                 }
 290                 if ((entry = ldap_first_entry(conn, msg)) == NULL)
 291                 {
 292                         if (verbose)
 293                                 ServerInstance->SNO->WriteToSnoMask('c', "Forbidden connection from %s (LDAP search returned no results: %s)", user->GetFullRealHost().c_str(), ldap_err2string(res));
 294                         ldap_msgfree(msg);
 295                         return false;
 296                 }
 297                 cred.bv_val = (char*)user->password.data();
 298                 cred.bv_len = user->password.length();
 299                 if ((res = ldap_sasl_bind_s(conn, ldap_get_dn(conn, entry), LDAP_SASL_SIMPLE, &cred, NULL, NULL, NULL)) != LDAP_SUCCESS)
 300                 {
 301                         if (verbose)
 302                                 ServerInstance->SNO->WriteToSnoMask('c', "Forbidden connection from %s (%s)", user->GetFullRealHost().c_str(), ldap_err2string(res));
 303                         ldap_msgfree(msg);
 304                         return false;
 305                 }
 306
 307                 if (!requiredattributes.empty())
 308                 {
 309                         bool authed = false;
 310
 311                         for (std::vector<std::pair<std::string, std::string> >::const_iterator it = requiredattributes.begin(); it != requiredattributes.end(); ++it)
 312                         {
 313                                 const std::string &attr = it->first;
 314                                 const std::string &val = it->second;
 315
 316                                 struct berval attr_value;
 317                                 attr_value.bv_val = const_cast<char*>(val.c_str());
 318                                 attr_value.bv_len = val.length();
 319
 320                                 ServerInstance->Logs->Log("m_ldapauth", DEBUG, "LDAP compare: %s=%s", attr.c_str(), val.c_str());
 321
 322                                 authed = (ldap_compare_ext_s(conn, ldap_get_dn(conn, entry), attr.c_str(), &attr_value, NULL, NULL) == LDAP_COMPARE_TRUE);
 323
 324                                 if (authed)
 325                                         break;
 326                         }
 327
 328                         if (!authed)
 329                         {
 330                                 if (verbose)
 331                                         ServerInstance->SNO->WriteToSnoMask('c', "Forbidden connection from %s (Lacks required LDAP attributes)", user->GetFullRealHost().c_str());
 332                                 ldap_msgfree(msg);
 333                                 return false;
 334                         }
 335                 }
 336
 337                 if (!vhost.empty())
 338                 {
 339                         irc::commasepstream stream(ldap_get_dn(conn, entry));
 340
 341                         // mashed map of key:value parts of the DN
 342                         std::map<std::string, std::string> dnParts;
 343
 344                         std::string dnPart;
 345                         while (stream.GetToken(dnPart))
 346                         {
 347                                 std::string::size_type pos = dnPart.find('=');
 348                                 if (pos == std::string::npos) // malformed
 349                                         continue;
 350
 351                                 std::string key = dnPart.substr(0, pos);
 352                                 std::string value = dnPart.substr(pos + 1, dnPart.length() - pos + 1); // +1s to skip the = itself
 353                                 dnParts[key] = value;
 354                         }
 355
 356                         // change host according to config key
 357                         ldapVhost.set(user, SafeReplace(vhost, dnParts));
 358                 }
 359
 360                 ldap_msgfree(msg);
 361                 ldapAuthed.set(user,1);
 362                 return true;
 363         }
 364
 365         ModResult OnCheckReady(LocalUser* user)
 366         {
 367                 return ldapAuthed.get(user) ? MOD_RES_PASSTHRU : MOD_RES_DENY;
 368         }
 369
 370         Version GetVersion()
 371         {
 372                 return Version("Allow/Deny connections based upon answer from LDAP server", VF_VENDOR);
 373         }
 374
 375 };
 376
 377 MODULE_INIT(ModuleLDAPAuth)