src/modules/m_codepage.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2020 Sadie Powell <sadie@witchery.services>
   5  *
   6  * This file is part of InspIRCd.  InspIRCd is free software: you can
   7  * redistribute it and/or modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation, version 2.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  12  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  13  * details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #include "inspircd.h"
  21
  22 typedef std::bitset<UCHAR_MAX + 1> AllowedChars;
  23
  24 namespace
  25 {
  26         // The characters which are allowed in nicknames.
  27         AllowedChars allowedchars;
  28
  29         // The characters which are allowed at the front of a nickname.
  30         AllowedChars allowedfrontchars;
  31
  32         // The mapping of lower case characters to upper case characters.
  33         unsigned char casemap[UCHAR_MAX];
  34
  35         bool IsValidNick(const std::string& nick)
  36         {
  37                 if (nick.empty() || nick.length() > ServerInstance->Config->Limits.NickMax)
  38                         return false;
  39
  40                 for (std::string::const_iterator iter = nick.begin(); iter != nick.end(); ++iter)
  41                 {
  42                         unsigned char chr = static_cast<unsigned char>(*iter);
  43
  44                         // Check that the character is allowed at the front of the nick.
  45                         if (iter == nick.begin() && !allowedfrontchars[chr])
  46                                 return false;
  47
  48                         // Check that the character is allowed in the nick.
  49                         if (!allowedchars[chr])
  50                                 return false;
  51                 }
  52
  53                 return true;
  54         }
  55 }
  56
  57 class ModuleCodepage
  58         : public Module
  59 {
  60  private:
  61         // The character map which was set before this module was loaded.
  62         const unsigned char* origcasemap;
  63
  64         // The name of the character map which was set before this module was loaded.
  65         const std::string origcasemapname;
  66
  67         // The IsNick handler which was set before this module was loaded.
  68         const TR1NS::function<bool(const std::string&)> origisnick;
  69
  70         template <typename T>
  71         void RehashHashmap(T& hashmap)
  72         {
  73                 T newhash(hashmap.bucket_count());
  74                 for (typename T::const_iterator i = hashmap.begin(); i != hashmap.end(); ++i)
  75                         newhash.insert(std::make_pair(i->first, i->second));
  76                 hashmap.swap(newhash);
  77         }
  78
  79         void CheckDuplicateNick()
  80         {
  81                 insp::flat_set<std::string, irc::insensitive_swo> duplicates;
  82                 const UserManager::LocalList& list = ServerInstance->Users.GetLocalUsers();
  83                 for (UserManager::LocalList::const_iterator iter = list.begin(); iter != list.end(); ++iter)
  84                 {
  85                         LocalUser* user = *iter;
  86                         if (user->nick != user->uuid && !duplicates.insert(user->nick).second)
  87                         {
  88                                 user->WriteNumeric(RPL_SAVENICK, user->uuid, "Your nickname is no longer available.");
  89                                 user->ChangeNick(user->uuid);
  90                         }
  91                 }
  92         }
  93
  94         void CheckInvalidNick()
  95         {
  96                 const UserManager::LocalList& list = ServerInstance->Users.GetLocalUsers();
  97                 for (UserManager::LocalList::const_iterator iter = list.begin(); iter != list.end(); ++iter)
  98                 {
  99                         LocalUser* user = *iter;
 100                         if (user->nick != user->uuid && !ServerInstance->IsNick(user->nick))
 101                         {
 102                                 user->WriteNumeric(RPL_SAVENICK, user->uuid, "Your nickname is no longer valid.");
 103                                 user->ChangeNick(user->uuid);
 104                         }
 105                 }
 106         }
 107
 108         void CheckRehash(unsigned char* prevmap)
 109         {
 110                 if (!memcmp(prevmap, national_case_insensitive_map, UCHAR_MAX))
 111                         return;
 112
 113                 RehashHashmap(ServerInstance->Users.clientlist);
 114                 RehashHashmap(ServerInstance->Users.uuidlist);
 115                 RehashHashmap(ServerInstance->chanlist);
 116         }
 117
 118  public:
 119         ModuleCodepage()
 120                 : origcasemap(national_case_insensitive_map)
 121                 , origcasemapname(ServerInstance->Config->CaseMapping)
 122                 , origisnick(ServerInstance->IsNick)
 123         {
 124         }
 125
 126         ~ModuleCodepage()
 127         {
 128                 ServerInstance->IsNick = origisnick;
 129                 CheckInvalidNick();
 130
 131                 ServerInstance->Config->CaseMapping = origcasemapname;
 132                 national_case_insensitive_map = origcasemap;
 133                 CheckDuplicateNick();
 134                 CheckRehash(casemap);
 135
 136                 ServerInstance->ISupport.Build();
 137         }
 138
 139         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 140         {
 141                 const std::string name = ServerInstance->Config->ConfValue("codepage")->getString("name");
 142                 if (name.empty())
 143                         throw ModuleException("<codepage:name> is a required field!");
 144
 145                 AllowedChars newallowedchars;
 146                 AllowedChars newallowedfrontchars;
 147                 ConfigTagList cpchars = ServerInstance->Config->ConfTags("cpchars");
 148                 for (ConfigIter i = cpchars.first; i != cpchars.second; ++i)
 149                 {
 150                         ConfigTag* tag = i->second;
 151
 152                         unsigned char begin = tag->getUInt("begin", tag->getUInt("index", 0), 1, UCHAR_MAX);
 153                         if (!begin)
 154                                 throw ModuleException("<cpchars> tag without index or begin specified at " + tag->getTagLocation());
 155
 156                         unsigned char end = tag->getUInt("end", begin, 1, UCHAR_MAX);
 157                         if (begin > end)
 158                                 throw ModuleException("<cpchars:begin> must be lower than <cpchars:end> at " + tag->getTagLocation());
 159
 160                         bool front = tag->getBool("front", false);
 161                         for (unsigned short pos = begin; pos <= end; ++pos)
 162                         {
 163                                 if (pos == '\n' || pos == '\r' || pos == ' ')
 164                                 {
 165                                         throw ModuleException(InspIRCd::Format("<cpchars> tag contains a forbidden character: %u at %s",
 166                                                 pos, tag->getTagLocation().c_str()));
 167                                 }
 168
 169                                 if (front && (pos == ':' || isdigit(pos)))
 170                                 {
 171                                         throw ModuleException(InspIRCd::Format("<cpchars> tag contains a forbidden front character: %u at %s",
 172                                                 pos, tag->getTagLocation().c_str()));
 173                                 }
 174
 175                                 newallowedchars.set(pos);
 176                                 newallowedfrontchars.set(pos, front);
 177                                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Marked %u (%c) as allowed (front: %s)",
 178                                         pos, pos, front ? "yes" : "no");
 179                         }
 180                 }
 181
 182                 unsigned char newcasemap[UCHAR_MAX];
 183                 for (size_t i = 0; i < UCHAR_MAX; ++i)
 184                         newcasemap[i] = i;
 185                 ConfigTagList cpcase = ServerInstance->Config->ConfTags("cpcase");
 186                 for (ConfigIter i = cpcase.first; i != cpcase.second; ++i)
 187                 {
 188                         ConfigTag* tag = i->second;
 189
 190                         unsigned char lower = tag->getUInt("lower", 0, 1, UCHAR_MAX);
 191                         if (!lower)
 192                                 throw ModuleException("<cpcase:lower> is required at " + tag->getTagLocation());
 193
 194                         unsigned char upper = tag->getUInt("upper", 0, 1, UCHAR_MAX);
 195                         if (!upper)
 196                                 throw ModuleException("<cpcase:upper> is required at " + tag->getTagLocation());
 197
 198                         newcasemap[upper] = lower;
 199                         ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Marked %u (%c) as the lower case version of %u (%c)",
 200                                 lower, lower, upper, upper);
 201                 }
 202
 203                 std::swap(allowedchars, newallowedchars);
 204                 std::swap(allowedfrontchars, newallowedfrontchars);
 205                 std::swap(casemap, newcasemap);
 206
 207                 ServerInstance->IsNick = &IsValidNick;
 208                 CheckInvalidNick();
 209
 210                 ServerInstance->Config->CaseMapping = name;
 211                 national_case_insensitive_map = casemap;
 212                 CheckRehash(newcasemap);
 213
 214                 ServerInstance->ISupport.Build();
 215         }
 216
 217         Version GetVersion() CXX11_OVERRIDE
 218         {
 219                 std::stringstream linkdata;
 220
 221                 linkdata << "front=";
 222                 for (size_t i = 0; i < allowedfrontchars.size(); ++i)
 223                         if (allowedfrontchars[i])
 224                                 linkdata << static_cast<unsigned char>(i);
 225
 226                 linkdata << "&middle=";
 227                 for (size_t i = 0; i < allowedchars.size(); ++i)
 228                         if (allowedchars[i])
 229                                 linkdata << static_cast<unsigned char>(i);
 230
 231                 linkdata << "&map=";
 232                 for (size_t i = 0; i < sizeof(casemap); ++i)
 233                         if (casemap[i] != i)
 234                                 linkdata << static_cast<unsigned char>(i) << casemap[i] << ',';
 235
 236                 return Version("Allows the server administrator to define what characters are allowed in nicknames and how characters should be compared in a case insensitive way.", VF_COMMON | VF_VENDOR, linkdata.str());
 237         }
 238 };
 239 MODULE_INIT(ModuleCodepage)