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         }
 105
 106         ModeAction OnSet(User* source, Channel* channel, std::string& parameter)
 107         {
 108                 irc::sepstream stream(parameter, ':');
 109                 AntiCapsMethod method;
 110                 uint16_t minlen;
 111                 uint8_t percent;
 112
 113                 // Attempt to parse the method.
 114                 if (!ParseMethod(stream, method) || !ParseMinimumLength(stream, minlen) || !ParsePercent(stream, percent))
 115                 {
 116                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, "Invalid anticaps mode parameter. Syntax: <ban|block|mute|kick|kickban>:{minlen}:{percent}."));
 117                         return MODEACTION_DENY;
 118                 }
 119
 120                 ext.set(channel, new AntiCapsSettings(method, minlen, percent));
 121                 return MODEACTION_ALLOW;
 122         }
 123
 124         void SerializeParam(Channel* chan, const AntiCapsSettings* acs, std::string& out)
 125         {
 126                 switch (acs->method)
 127                 {
 128                         case ACM_BAN:
 129                                 out.append("ban");
 130                                 break;
 131                         case ACM_BLOCK:
 132                                 out.append("block");
 133                                 break;
 134                         case ACM_MUTE:
 135                                 out.append("mute");
 136                                 break;
 137                         case ACM_KICK:
 138                                 out.append("kick");
 139                                 break;
 140                         case ACM_KICK_BAN:
 141                                 out.append("kickban");
 142                                 break;
 143                         default:
 144                                 out.append("unknown~");
 145                                 out.append(ConvToStr(acs->method));
 146                                 break;
 147                 }
 148                 out.push_back(':');
 149                 out.append(ConvToStr(acs->minlen));
 150                 out.push_back(':');
 151                 out.append(ConvToStr(acs->percent));
 152         }
 153 };
 154
 155 class ModuleAntiCaps : public Module
 156 {
 157  private:
 158         CheckExemption::EventProvider exemptionprov;
 159         std::bitset<UCHAR_MAX> uppercase;
 160         std::bitset<UCHAR_MAX> lowercase;
 161         AntiCapsMode mode;
 162
 163         void CreateBan(Channel* channel, User* user, bool mute)
 164         {
 165                 std::string banmask(mute ? "m:" : "");
 166                 banmask.append("*!*@");
 167                 banmask.append(user->GetDisplayedHost());
 168
 169                 Modes::ChangeList changelist;
 170                 changelist.push_add(ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL), banmask);
 171                 ServerInstance->Modes->Process(ServerInstance->FakeClient, channel, NULL, changelist);
 172         }
 173
 174         void InformUser(Channel* channel, User* user, const std::string& message)
 175         {
 176                 user->WriteNumeric(ERR_CANNOTSENDTOCHAN, channel, message + " and was blocked.");
 177         }
 178
 179  public:
 180         ModuleAntiCaps()
 181                 : exemptionprov(this)
 182                 , mode(this)
 183         {
 184         }
 185
 186         void ReadConfig(ConfigStatus&) CXX11_OVERRIDE
 187         {
 188                 ConfigTag* tag = ServerInstance->Config->ConfValue("anticaps");
 189
 190                 uppercase.reset();
 191                 const std::string upper = tag->getString("uppercase", "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
 192                 for (std::string::const_iterator iter = upper.begin(); iter != upper.end(); ++iter)
 193                         uppercase.set(static_cast<unsigned char>(*iter));
 194
 195                 lowercase.reset();
 196                 const std::string lower = tag->getString("lowercase", "abcdefghijklmnopqrstuvwxyz");
 197                 for (std::string::const_iterator iter = lower.begin(); iter != lower.end(); ++iter)
 198                         lowercase.set(static_cast<unsigned char>(*iter));
 199         }
 200
 201         ModResult OnUserPreMessage(User* user, const MessageTarget& target, MessageDetails& details) CXX11_OVERRIDE
 202         {
 203                 // We only want to operate on messages from local users.
 204                 if (!IS_LOCAL(user))
 205                         return MOD_RES_PASSTHRU;
 206
 207                 // The mode can only be applied to channels.
 208                 if (target.type != MessageTarget::TYPE_CHANNEL)
 209                         return MOD_RES_PASSTHRU;
 210
 211                 // We only act if the channel has the mode set.
 212                 Channel* channel = target.Get<Channel>();
 213                 if (!channel->IsModeSet(&mode))
 214                         return MOD_RES_PASSTHRU;
 215
 216                 // If the user is exempt from anticaps then we don't need
 217                 // to do anything else.
 218                 ModResult result = CheckExemption::Call(exemptionprov, user, channel, "anticaps");
 219                         if (result == MOD_RES_ALLOW)
 220                         return MOD_RES_PASSTHRU;
 221
 222                 // If the message is a CTCP then we skip it unless it is
 223                 // an ACTION in which case we skip the prefix and suffix.
 224                 std::string::const_iterator text_begin = details.text.begin();
 225                 std::string::const_iterator text_end = details.text.end();
 226                 if (details.text[0] == '\1')
 227                 {
 228                         // If the CTCP is not an action then skip it.
 229                         if (details.text.compare(0, 8, "\1ACTION ", 8))
 230                                 return MOD_RES_PASSTHRU;
 231
 232                         // Skip the CTCP message characters.
 233                         text_begin += 8;
 234                         if (*details.text.rbegin() == '\1')
 235                                 text_end -= 1;
 236                 }
 237
 238                 // Retrieve the anticaps config. This should never be
 239                 // null but its better to be safe than sorry.
 240                 AntiCapsSettings* config = mode.ext.get(channel);
 241                 if (!config)
 242                         return MOD_RES_PASSTHRU;
 243
 244                 // If the message is shorter than the minimum length then
 245                 // we don't need to do anything else.
 246                 size_t length = std::distance(text_begin, text_end);
 247                 if (length < config->minlen)
 248                         return MOD_RES_PASSTHRU;
 249
 250                 // Count the characters to see how many upper case and
 251                 // ignored (non upper or lower) characters there are.
 252                 size_t upper = 0;
 253                 for (std::string::const_iterator iter = text_begin; iter != text_end; ++iter)
 254                 {
 255                         unsigned char chr = static_cast<unsigned char>(*iter);
 256                         if (uppercase.test(chr))
 257                                 upper += 1;
 258                         else if (!lowercase.test(chr))
 259                                 length -= 1;
 260                 }
 261
 262                 // If the message was entirely symbols then the message
 263                 // can't contain any upper case letters.
 264                 if (length == 0)
 265                         return MOD_RES_PASSTHRU;
 266
 267                 // Calculate the percentage.
 268                 double percent = round((upper * 100) / length);
 269                 if (percent < config->percent)
 270                         return MOD_RES_PASSTHRU;
 271
 272                 const std::string message = InspIRCd::Format("Your message exceeded the %d%% upper case character threshold for %s",
 273                         config->percent, channel->name.c_str());
 274
 275                 switch (config->method)
 276                 {
 277                         case ACM_BAN:
 278                                 InformUser(channel, user, message);
 279                                 CreateBan(channel, user, false);
 280                                 break;
 281
 282                         case ACM_BLOCK:
 283                                 InformUser(channel, user, message);
 284                                 break;
 285
 286                         case ACM_MUTE:
 287                                 InformUser(channel, user, message);
 288                                 CreateBan(channel, user, true);
 289                                 break;
 290
 291                         case ACM_KICK:
 292                                 channel->KickUser(ServerInstance->FakeClient, user, message);
 293                                 break;
 294
 295                         case ACM_KICK_BAN:
 296                                 CreateBan(channel, user, false);
 297                                 channel->KickUser(ServerInstance->FakeClient, user, message);
 298                                 break;
 299                 }
 300                 return MOD_RES_DENY;
 301         }
 302
 303         Version GetVersion() CXX11_OVERRIDE
 304         {
 305                 return Version("Provides support for punishing users that send capitalised messages.", VF_COMMON|VF_VENDOR);
 306         }
 307 };
 308
 309 MODULE_INIT(ModuleAntiCaps)