Home

Script: weefish.rb

FiSH encryption/decryption. (for WeeChat ≥ 0.3.0, requires: crypt/blowfish)
Author: tp, version 0.4, GPL3 — added: 2010-09-19, updated: 2012-02-08
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
##
# weefish.rb
#
# Copyright (c) 2010 by Tobias Petersen <tp@unreal.dk>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# 
# FiSH encryption / decryption for Weechat
# based on blowfish, it is compatible with other
# FiSH scripts created for mIRC, irssi and XChat
#
# Thanks to someone without a name, for creating the FiSH script in ruby
# No DH1080 key exchange, only manual key, sorry!
#
# Usage:
#   Set key for a given nick/channel, or the active nick/channel:
#     /setkey [nick/channel] <secure key>
#   Delete key for a given nick/channel, or the active nick/channel:
#     /delkey [nick/channel] <secure key>
#
# History:
#   2012-02-08 bazerka <bazerka@irssi.org>
#     version 0.4: fix in_privmsg to work with user targeted privmsg.
#                  bypass decrypting in_privmsg when no key is found.
#   2011-03-08 tp <tp@unreal.dk>
#     version 0.3: fixed crypt/blowfish bug for ruby >= 1.9
#   2010-09-06, tp <tp@unreal.dk>
#     version 0.2: fixed some message printing
#   2010-09-05, tp <tp@unreal.dk>
#     version 0.1: initial release

require "crypt/blowfish"

def message buffer, message
  Weechat.print buffer, "#{Weechat.prefix('error')}#{Weechat.color('bold')}weefish:#{Weechat.color('-bold')} #{message}"
end

def weechat_init
  Weechat.register "weefish", "Tobias Petersen", "0.4", "GPL3", "FiSH encryption/decryption", "", ""
  
  Weechat.hook_modifier "irc_in_privmsg", "in_privmsg", ""
  Weechat.hook_modifier "irc_out_privmsg", "out_privmsg", ""
  
  Weechat.hook_command "setkey", "Set the encryption key for the active nick/channel", "[nick/channel] <secure key>", "", "", "setkey", ""
  Weechat.hook_command "delkey", "Delete the encryption key for the active nick/channel", "[nick/channel] <secure key>", "", "", "delkey", ""
  
  return Weechat::WEECHAT_RC_OK
end

if RUBY_VERSION.to_f >= 1.9
  module ::Crypt
    class Blowfish
      def setup_blowfish
        @sBoxes = Array.new(4) { |i| INITIALSBOXES[i].clone }
        @pArray = INITIALPARRAY.clone
        keypos = 0
        0.upto(17) { |i|
          data = 0
          4.times {
            data = ((data << 8) | @key[keypos].ord) % ULONG
            keypos = (keypos.next) % @key.length
          }
          @pArray[i] = (@pArray[i] ^ data) % ULONG
        }
        l = 0
        r = 0
        0.step(17, 2) { |i|
          l, r = encrypt_pair(l, r)
          @pArray[i]   = l
          @pArray[i+1] = r
        }
        0.upto(3) { |i|
          0.step(255, 2) { |j|
            l, r = encrypt_pair(l, r)
            @sBoxes[i][j]   = l
            @sBoxes[i][j+1] = r
          }
        }
      end
    end
  end
end

def setkey data, buffer, key
  network, channel = Weechat.buffer_get_string(buffer, "name").split ".", 2
  
  unless key.empty?
    if key.scan(" ").length == 0
      if network == "server"
        message buffer, "No active nick/channel. Usage: /setkey <nick/channel> <secure key>"
      else
        message buffer, "Key for #{channel} (#{network}) successfully set!"
        Weechat.config_set_plugin "key.#{network}.#{channel}", key
      end
    else
      network = channel if network == "server"
      channel, key = key.split " ", 2
      
      message buffer, "Key for #{channel} (#{network}) successfully set!"
      Weechat.config_set_plugin "key.#{network}.#{channel}", key
    end
  else
    message buffer, "No parameters. Usage: /setkey [nick/channel] <secure key>"
  end
end

def delkey data, buffer, string
  network, channel = Weechat.buffer_get_string(buffer, "name").split ".", 2
  
  if string.empty?
    if network == "server"
      message buffer, "No active nick/channel. Usage: /delkey <nick/channel>"
    else
      Weechat.config_unset_plugin "key.#{network}.#{channel}"
      message buffer, "Key for #{channel} (#{network}) successfully deleted!"
    end
  else
    network = channel if network == "server"
    Weechat.config_unset_plugin "key.#{network}.#{string.split.first}"
    message buffer, "Key for #{string.split.first} (#{network}) successfully deleted!"
  end
end

def in_privmsg data, signal, server, args
  if args =~ /^(:(.*?)!.*? PRIVMSG (.*?) :)(\+OK|mcps) (.*)$/
	# If the PRIVMSG target ($3) is our current nick, we need the source nick ($2) to select the key
    # config variable. Otherwise, assume it's a channel and use that to select the key instead.
    selector = $3 == Weechat.info_get("irc_nick", server) ? $2 : $3
    key = Weechat.config_string Weechat.config_get("plugins.var.ruby.weefish.key.#{server}.#{selector}")
    
    # If we couldn't find a key, don't attempt to decrypt the message as Crypt::Blowfish will raise an
    # invalid key length error on initialisation.
	unless key.empty?
      fish = IRC::FiSH.new key
      if decrypted = fish.decrypt($5)
        return $1+decrypted
      end
    end
  end
  return args
end

def out_privmsg data, signal, server, args
  if args =~ /^(PRIVMSG (.*?) :)(.*)$/
    key = Weechat.config_string Weechat.config_get("plugins.var.ruby.weefish.key.#{server}.#{$2}")
    
    unless key.empty?
      fish = IRC::FiSH.new key
      return "#{$1}+OK #{fish.encrypt $3}"
    else
      return args
    end
  end
  return args
end

module IRC
  class BadInputError < StandardError; end
  
  class MBase64
    B64 = "./0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
    
    def self.decode encoded
      return nil if not encoded.length % 12 == 0
      
      decoded = String.new
      
      k = -1
      while (k < encoded.length - 1) do
        right = 0
        left = 0
        
        (0..5).each do |i|
          k = k + 1
          right |= B64.index(encoded[k]) << (i * 6)
        end
        
        (0..5).each do |i|
          k = k + 1
          left |= B64.index(encoded[k]) << (i * 6)
        end
        
        (0..3).each do |i|
          decoded += ((left & (0xFF << ((3 - i) * 8))) >> ((3 - i) * 8)).chr
        end
        
        (0..3).each do |i|
          decoded += ((right & (0xFF << ((3 - i) * 8))) >> ((3 - i) * 8)).chr
        end
      end
      
      return decoded
    end
    
    def self.encode decoded
      if not decoded.length % 8 == 0
        raise IRC::BadInputError,
          "can only encode strings which are a multiple of 8 characters."
      end
      
      encoded = String.new
      
      k = -1
      
      while (k < decoded.length - 1) do
        k = k.next
        left = (decoded[k].ord << 24)
        k = k.next
        left += (decoded[k].ord << 16)
        k = k.next
        left += (decoded[k].ord << 8)
        k = k.next
        left += decoded[k].ord
        
        k = k.next
        right = (decoded[k].ord << 24)
        k = k.next
        right += (decoded[k].ord << 16)
        k = k.next
        right += (decoded[k].ord << 8)
        k = k.next
        right += decoded[k].ord
        
        (0..5).each do
          encoded += B64[right & 0x3F].chr
          right = right >> 6
        end
        (0..5).each do
          encoded += B64[left & 0x3F].chr
          left = left >> 6
        end
      end
      
      return encoded
    end
  end
  
  class FiSH
    def initialize key
      @blowfish = Crypt::Blowfish.new key
    end
    
    def encrypt text
      text = pad(text, 8)
      result = ""
      
      num_block = text.length / 8
      num_block.times do |n|
        block = text[n*8..(n+1)*8-1]
        enc = @blowfish.encrypt_block(block)
        result += MBase64.encode(enc)
      end
      
      return result
    end
    
    def decrypt text
      return nil if not text.length % 12 == 0
      
      result = ""
      
      num_block = (text.length / 12).to_i
      num_block.times do |n|
        block = MBase64.decode( text[n*12..(n+1)*12-1] )
        result += @blowfish.decrypt_block(block)
      end
      
      return result.gsub /\0*$/, ""
    end
    
    private
    
    def pad text, n=8
      pad_num = n - (text.length % n)
      if pad_num > 0 and pad_num != n
        pad_num.times { text += 0.chr }
      end
      return text
    end
  end
  
end