src/modules/m_codepage.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2020 Sadie Powell <sadie@witchery.services>
   5  *   Copyright (C) 2014 Googolplexed <googol@googolplexed.net>
   6  *
   7  * This file is part of InspIRCd.  InspIRCd is free software: you can
   8  * redistribute it and/or modify it under the terms of the GNU General Public
   9  * License as published by the Free Software Foundation, version 2.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  14  * details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20
  21 #include "inspircd.h"
  22
  23 typedef std::bitset<UCHAR_MAX + 1> AllowedChars;
  24
  25 namespace
  26 {
  27         // The characters which are allowed in nicknames.
  28         AllowedChars allowedchars;
  29
  30         // The characters which are allowed at the front of a nickname.
  31         AllowedChars allowedfrontchars;
  32
  33         // The mapping of lower case characters to upper case characters.
  34         unsigned char casemap[UCHAR_MAX];
  35
  36         bool IsValidNick(const std::string& nick)
  37         {
  38                 if (nick.empty() || nick.length() > ServerInstance->Config->Limits.NickMax)
  39                         return false;
  40
  41                 for (std::string::const_iterator iter = nick.begin(); iter != nick.end(); ++iter)
  42                 {
  43                         unsigned char chr = static_cast<unsigned char>(*iter);
  44
  45                         // Check that the character is allowed at the front of the nick.
  46                         if (iter == nick.begin() && !allowedfrontchars[chr])
  47                                 return false;
  48
  49                         // Check that the character is allowed in the nick.
  50                         if (!allowedchars[chr])
  51                                 return false;
  52                 }
  53
  54                 return true;
  55         }
  56 }
  57
  58 class ModuleCodepage
  59         : public Module
  60 {
  61  private:
  62         // The character map which was set before this module was loaded.
  63         const unsigned char* origcasemap;
  64
  65         // The name of the character map which was set before this module was loaded.
  66         const std::string origcasemapname;
  67
  68         // The IsNick handler which was set before this module was loaded.
  69         const TR1NS::function<bool(const std::string&)> origisnick;
  70
  71         template <typename T>
  72         void RehashHashmap(T& hashmap)
  73         {
  74                 T newhash(hashmap.bucket_count());
  75                 for (typename T::const_iterator i = hashmap.begin(); i != hashmap.end(); ++i)
  76                         newhash.insert(std::make_pair(i->first, i->second));
  77                 hashmap.swap(newhash);
  78         }
  79
  80         void CheckInvalidNick()
  81         {
  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 && !ServerInstance->IsNick(user->nick))
  87                                 user->ChangeNick(user->uuid);
  88                 }
  89         }
  90
  91         void CheckRehash(unsigned char* prevmap)
  92         {
  93                 if (!memcmp(prevmap, national_case_insensitive_map, UCHAR_MAX))
  94                         return;
  95
  96                 RehashHashmap(ServerInstance->Users.clientlist);
  97                 RehashHashmap(ServerInstance->Users.uuidlist);
  98                 RehashHashmap(ServerInstance->chanlist);
  99         }
 100
 101  public:
 102         ModuleCodepage()
 103                 : origcasemap(national_case_insensitive_map)
 104                 , origcasemapname(ServerInstance->Config->CaseMapping)
 105                 , origisnick(ServerInstance->IsNick)
 106         {
 107         }
 108
 109         ~ModuleCodepage()
 110         {
 111                 ServerInstance->IsNick = origisnick;
 112                 CheckInvalidNick();
 113
 114                 ServerInstance->Config->CaseMapping = origcasemapname;
 115                 national_case_insensitive_map = origcasemap;
 116                 CheckRehash(casemap);
 117         }
 118
 119         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 120         {
 121                 const std::string name = ServerInstance->Config->ConfValue("codepage")->getString("name");
 122                 if (name.empty())
 123                         throw ModuleException("<codepage:name> is a required field!");
 124
 125                 AllowedChars newallowedchars;
 126                 AllowedChars newallowedfrontchars;
 127                 ConfigTagList cpchars = ServerInstance->Config->ConfTags("cpchars");
 128                 for (ConfigIter i = cpchars.first; i != cpchars.second; ++i)
 129                 {
 130                         ConfigTag* tag = i->second;
 131
 132                         unsigned char begin = tag->getUInt("begin", tag->getUInt("index", 0), 1, UCHAR_MAX);
 133                         if (!begin)
 134                                 throw ModuleException("<cpchars> tag without index or begin specified at " + tag->getTagLocation());
 135
 136                         unsigned char end = tag->getUInt("end", begin, 1, UCHAR_MAX);
 137                         if (begin > end)
 138                                 throw ModuleException("<cpchars:begin> must be lower than <cpchars:end> at " + tag->getTagLocation());
 139
 140                         bool front = tag->getBool("front", false);
 141                         for (unsigned short pos = begin; pos <= end; ++pos)
 142                         {
 143                                 if (pos == '\n' || pos == '\r' || pos == ' ')
 144                                 {
 145                                         throw ModuleException(InspIRCd::Format("<cpchars> tag contains a forbidden character: %u at %s",
 146                                                 pos, tag->getTagLocation().c_str()));
 147                                 }
 148
 149                                 if (front && (pos == ':' || isdigit(pos)))
 150                                 {
 151                                         throw ModuleException(InspIRCd::Format("<cpchars> tag contains a forbidden front character: %u at %s",
 152                                                 pos, tag->getTagLocation().c_str()));
 153                                 }
 154
 155                                 newallowedchars.set(pos);
 156                                 newallowedfrontchars.set(pos, front);
 157                                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Marked %u (%c) as allowed (front: %s)",
 158                                         pos, pos, front ? "yes" : "no");
 159                         }
 160                 }
 161
 162                 unsigned char newcasemap[UCHAR_MAX];
 163                 for (size_t i = 0; i < UCHAR_MAX; ++i)
 164                         newcasemap[i] = i;
 165                 ConfigTagList cpcase = ServerInstance->Config->ConfTags("cpcase");
 166                 for (ConfigIter i = cpcase.first; i != cpcase.second; ++i)
 167                 {
 168                         ConfigTag* tag = i->second;
 169
 170                         unsigned char lower = tag->getUInt("lower", 0, 1, UCHAR_MAX);
 171                         if (!lower)
 172                                 throw ModuleException("<cpcase:lower> is required at " + tag->getTagLocation());
 173
 174                         unsigned char upper = tag->getUInt("upper", 0, 1, UCHAR_MAX);
 175                         if (!upper)
 176                                 throw ModuleException("<cpcase:upper> is required at " + tag->getTagLocation());
 177
 178                         newcasemap[upper] = lower;
 179                         ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Marked %u (%c) as the lower case version of %u (%c)",
 180                                 lower, lower, upper, upper);
 181                 }
 182
 183                 std::swap(allowedchars, newallowedchars);
 184                 std::swap(allowedfrontchars, newallowedfrontchars);
 185                 std::swap(casemap, newcasemap);
 186
 187                 ServerInstance->IsNick = &IsValidNick;
 188                 CheckInvalidNick();
 189
 190                 ServerInstance->Config->CaseMapping = name;
 191                 national_case_insensitive_map = casemap;
 192                 CheckRehash(newcasemap);
 193         }
 194
 195         Version GetVersion() CXX11_OVERRIDE
 196         {
 197                 std::stringstream linkdata;
 198
 199                 linkdata << "front=";
 200                 for (size_t i = 0; i < allowedfrontchars.size(); ++i)
 201                         if (allowedfrontchars[i])
 202                                 linkdata << static_cast<unsigned char>(i);
 203
 204                 linkdata << "&middle=";
 205                 for (size_t i = 0; i < allowedchars.size(); ++i)
 206                         if (allowedchars[i])
 207                                 linkdata << static_cast<unsigned char>(i);
 208
 209                 linkdata << "&map=";
 210                 for (size_t i = 0; i < sizeof(casemap); ++i)
 211                         if (casemap[i] != i)
 212                                 linkdata << static_cast<unsigned char>(i) << casemap[i] << ',';
 213
 214                 return Version("Provides support for custom 8-bit codepages", VF_COMMON | VF_VENDOR, linkdata.str());
 215         }
 216 };
 217 MODULE_INIT(ModuleCodepage)