src/modules/m_anticaps.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2017 Peter Powell <petpow@saberuk.com>
   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 #include "modules/exemption.h"
  22
  23 enum AntiCapsMethod
  24 {
  25         ACM_BAN,
  26         ACM_BLOCK,
  27         ACM_MUTE,
  28         ACM_KICK,
  29         ACM_KICK_BAN
  30 };
  31
  32 class AntiCapsSettings
  33 {
  34  public:
  35         const AntiCapsMethod method;
  36         const uint16_t minlen;
  37         const uint8_t percent;
  38
  39         AntiCapsSettings(const AntiCapsMethod& Method, const uint16_t& MinLen, const uint8_t& Percent)
  40                 : method(Method)
  41                 , minlen(MinLen)
  42                 , percent(Percent)
  43         {
  44         }
  45 };
  46
  47 class AntiCapsMode : public ParamMode<AntiCapsMode, SimpleExtItem<AntiCapsSettings> >
  48 {
  49  private:
  50         bool ParseMethod(irc::sepstream& stream, AntiCapsMethod& method)
  51         {
  52                 std::string methodstr;
  53                 if (!stream.GetToken(methodstr))
  54                         return false;
  55
  56                 if (irc::equals(methodstr, "ban"))
  57                         method = ACM_BAN;
  58                 else if (irc::equals(methodstr, "block"))
  59                         method = ACM_BLOCK;
  60                 else if (irc::equals(methodstr, "mute"))
  61                         method = ACM_MUTE;
  62                 else if (irc::equals(methodstr, "kick"))
  63                         method = ACM_KICK;
  64                 else if (irc::equals(methodstr, "kickban"))
  65                         method = ACM_KICK_BAN;
  66                 else
  67                         return false;
  68
  69                 return true;
  70         }
  71
  72         bool ParseMinimumLength(irc::sepstream& stream, uint16_t& minlen)
  73         {
  74                 std::string minlenstr;
  75                 if (!stream.GetToken(minlenstr))
  76                         return false;
  77
  78                 uint16_t result = ConvToNum<uint16_t>(minlenstr);
  79                 if (result < 1 || result > ServerInstance->Config->Limits.MaxLine)
  80                         return false;
  81
  82                 minlen = result;
  83                 return true;
  84         }
  85
  86         bool ParsePercent(irc::sepstream& stream, uint8_t& percent)
  87         {
  88                 std::string percentstr;
  89                 if (!stream.GetToken(percentstr))
  90                         return false;
  91
  92                 uint8_t result = ConvToNum<uint8_t>(percentstr);
  93                 if (result < 1 || result > 100)
  94                         return false;
  95
  96                 percent = result;
  97                 return true;
  98         }
  99
 100  public:
 101         AntiCapsMode(Module* Creator)
 102                 : ParamMode<AntiCapsMode, SimpleExtItem<AntiCapsSettings> >(Creator, "anticaps", 'B')
 103         {
 104                 syntax = "{ban|block|mute|kick|kickban}:<minlen>:<percent>";
 105         }
 106
 107         ModeAction OnSet(User* source, Channel* channel, std::string& parameter) CXX11_OVERRIDE
 108         {
 109                 irc::sepstream stream(parameter, ':');
 110                 AntiCapsMethod method;
 111                 uint16_t minlen;
 112                 uint8_t percent;
 113
 114                 // Attempt to parse the method.
 115                 if (!ParseMethod(stream, method) || !ParseMinimumLength(stream, minlen) || !ParsePercent(stream, percent))
 116                 {
 117                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter));
 118                         return MODEACTION_DENY;
 119                 }
 120
 121                 ext.set(channel, new AntiCapsSettings(method, minlen, percent));
 122                 return MODEACTION_ALLOW;
 123         }
 124
 125         void SerializeParam(Channel* chan, const AntiCapsSettings* acs, std::string& out)
 126         {
 127                 switch (acs->method)
 128                 {
 129                         case ACM_BAN:
 130                                 out.append("ban");
 131                                 break;
 132                         case ACM_BLOCK:
 133                                 out.append("block");
 134                                 break;
 135                         case ACM_MUTE:
 136                                 out.append("mute");
 137                                 break;
 138                         case ACM_KICK:
 139                                 out.append("kick");
 140                                 break;
 141                         case ACM_KICK_BAN:
 142                                 out.append("kickban");
 143                                 break;
 144                         default:
 145                                 out.append("unknown~");
 146                                 out.append(ConvToStr(acs->method));
 147                                 break;
 148                 }
 149                 out.push_back(':');
 150                 out.append(ConvToStr(acs->minlen));
 151                 out.push_back(':');
 152                 out.append(ConvNumeric(acs->percent));
 153         }
 154 };
 155
 156 class ModuleAntiCaps : public Module
 157 {
 158  private:
 159         CheckExemption::EventProvider exemptionprov;
 160         std::bitset<UCHAR_MAX> uppercase;
 161         std::bitset<UCHAR_MAX> lowercase;
 162         AntiCapsMode mode;
 163
 164         void CreateBan(Channel* channel, User* user, bool mute)
 165         {
 166                 std::string banmask(mute ? "m:" : "");
 167                 banmask.append("*!*@");
 168                 banmask.append(user->GetDisplayedHost());
 169
 170                 Modes::ChangeList changelist;
 171                 changelist.push_add(ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL), banmask);
 172                 ServerInstance->Modes->Process(ServerInstance->FakeClient, channel, NULL, changelist);
 173         }
 174
 175         void InformUser(Channel* channel, User* user, const std::string& message)
 176         {
 177                 user->WriteNumeric(ERR_CANNOTSENDTOCHAN, channel->name, message + " and was blocked.");
 178         }
 179
 180  public:
 181         ModuleAntiCaps()
 182                 : exemptionprov(this)
 183                 , mode(this)
 184         {
 185         }
 186
 187         void ReadConfig(ConfigStatus&) CXX11_OVERRIDE
 188         {
 189                 ConfigTag* tag = ServerInstance->Config->ConfValue("anticaps");
 190
 191                 uppercase.reset();
 192                 const std::string upper = tag->getString("uppercase", "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
 193                 for (std::string::const_iterator iter = upper.begin(); iter != upper.end(); ++iter)
 194                         uppercase.set(static_cast<unsigned char>(*iter));
 195
 196                 lowercase.reset();
 197                 const std::string lower = tag->getString("lowercase", "abcdefghijklmnopqrstuvwxyz");
 198                 for (std::string::const_iterator iter = lower.begin(); iter != lower.end(); ++iter)
 199                         lowercase.set(static_cast<unsigned char>(*iter));
 200         }
 201
 202         ModResult OnUserPreMessage(User* user, const MessageTarget& target, MessageDetails& details) CXX11_OVERRIDE
 203         {
 204                 // We only want to operate on messages from local users.
 205                 if (!IS_LOCAL(user))
 206                         return MOD_RES_PASSTHRU;
 207
 208                 // The mode can only be applied to channels.
 209                 if (target.type != MessageTarget::TYPE_CHANNEL)
 210                         return MOD_RES_PASSTHRU;
 211
 212                 // We only act if the channel has the mode set.
 213                 Channel* channel = target.Get<Channel>();
 214                 if (!channel->IsModeSet(&mode))
 215                         return MOD_RES_PASSTHRU;
 216
 217                 // If the user is exempt from anticaps then we don't need
 218                 // to do anything else.
 219                 ModResult result = CheckExemption::Call(exemptionprov, user, channel, "anticaps");
 220                 if (result == MOD_RES_ALLOW)
 221                         return MOD_RES_PASSTHRU;
 222
 223                 // If the message is a CTCP then we skip it unless it is
 224                 // an ACTION in which case we just check against the body.
 225                 std::string ctcpname;
 226                 std::string msgbody(details.text);
 227                 if (details.IsCTCP(ctcpname, msgbody))
 228                 {
 229                         // If the CTCP is not an action then skip it.
 230                         if (!irc::equals(ctcpname, "ACTION"))
 231                                 return MOD_RES_PASSTHRU;
 232                 }
 233
 234                 // Retrieve the anticaps config. This should never be
 235                 // null but its better to be safe than sorry.
 236                 AntiCapsSettings* config = mode.ext.get(channel);
 237                 if (!config)
 238                         return MOD_RES_PASSTHRU;
 239
 240                 // If the message is shorter than the minimum length then
 241                 // we don't need to do anything else.
 242                 size_t length = msgbody.length();
 243                 if (length < config->minlen)
 244                         return MOD_RES_PASSTHRU;
 245
 246                 // Count the characters to see how many upper case and
 247                 // ignored (non upper or lower) characters there are.
 248                 size_t upper = 0;
 249                 for (std::string::const_iterator iter = msgbody.begin(); iter != msgbody.end(); ++iter)
 250                 {
 251                         unsigned char chr = static_cast<unsigned char>(*iter);
 252                         if (uppercase.test(chr))
 253                                 upper += 1;
 254                         else if (!lowercase.test(chr))
 255                                 length -= 1;
 256                 }
 257
 258                 // If the message was entirely symbols then the message
 259                 // can't contain any upper case letters.
 260                 if (length == 0)
 261                         return MOD_RES_PASSTHRU;
 262
 263                 // Calculate the percentage.
 264                 double percent = round((upper * 100) / length);
 265                 if (percent < config->percent)
 266                         return MOD_RES_PASSTHRU;
 267
 268                 const std::string message = InspIRCd::Format("Your message exceeded the %d%% upper case character threshold for %s",
 269                         config->percent, channel->name.c_str());
 270
 271                 switch (config->method)
 272                 {
 273                         case ACM_BAN:
 274                                 InformUser(channel, user, message);
 275                                 CreateBan(channel, user, false);
 276                                 break;
 277
 278                         case ACM_BLOCK:
 279                                 InformUser(channel, user, message);
 280                                 break;
 281
 282                         case ACM_MUTE:
 283                                 InformUser(channel, user, message);
 284                                 CreateBan(channel, user, true);
 285                                 break;
 286
 287                         case ACM_KICK:
 288                                 channel->KickUser(ServerInstance->FakeClient, user, message);
 289                                 break;
 290
 291                         case ACM_KICK_BAN:
 292                                 CreateBan(channel, user, false);
 293                                 channel->KickUser(ServerInstance->FakeClient, user, message);
 294                                 break;
 295                 }
 296                 return MOD_RES_DENY;
 297         }
 298
 299         Version GetVersion() CXX11_OVERRIDE
 300         {
 301                 return Version("Provides support for punishing users that send capitalised messages", VF_COMMON|VF_VENDOR);
 302         }
 303 };
 304
 305 MODULE_INIT(ModuleAntiCaps)