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1 -- sasl.lua v0.4 |
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2 -- Copyright (C) 2008-2009 Tobias Markmann |
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3 -- |
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4 -- All rights reserved. |
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5 -- |
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6 -- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: |
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7 -- |
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8 -- * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. |
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9 -- * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. |
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10 -- * Neither the name of Tobias Markmann nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. |
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11 -- |
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12 -- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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13 |
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14 local tostring = tostring; |
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15 local type = type; |
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16 |
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17 local s_gmatch = string.gmatch; |
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18 local s_match = string.match; |
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19 local t_concat = table.concat; |
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20 local t_insert = table.insert; |
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21 local to_byte, to_char = string.byte, string.char; |
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22 |
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23 local md5 = require "util.hashes".md5; |
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24 local log = require "util.logger".init("sasl"); |
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25 local generate_uuid = require "util.uuid".generate; |
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26 |
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27 module "plain" |
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28 |
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29 --========================= |
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30 --SASL DIGEST-MD5 according to RFC 2831 |
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31 local function digest_response() |
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32 |
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33 return response, A1, A2 |
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34 end |
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35 |
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36 local function digest(self, message) |
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37 --TODO complete support for authzid |
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38 |
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39 local function serialize(message) |
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40 local data = "" |
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41 |
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42 if type(message) ~= "table" then error("serialize needs an argument of type table.") end |
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43 |
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44 -- testing all possible values |
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45 if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end |
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46 if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end |
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47 if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end |
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48 if message["charset"] then data = data..[[charset=]]..message.charset.."," end |
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49 if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end |
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50 if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end |
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51 data = data:gsub(",$", "") |
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52 return data |
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53 end |
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54 |
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55 local function utf8tolatin1ifpossible(passwd) |
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56 local i = 1; |
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57 while i <= #passwd do |
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58 local passwd_i = to_byte(passwd:sub(i, i)); |
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59 if passwd_i > 0x7F then |
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60 if passwd_i < 0xC0 or passwd_i > 0xC3 then |
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61 return passwd; |
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62 end |
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63 i = i + 1; |
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64 passwd_i = to_byte(passwd:sub(i, i)); |
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65 if passwd_i < 0x80 or passwd_i > 0xBF then |
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66 return passwd; |
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67 end |
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68 end |
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69 i = i + 1; |
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70 end |
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71 |
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72 local p = {}; |
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73 local j = 0; |
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74 i = 1; |
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75 while (i <= #passwd) do |
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76 local passwd_i = to_byte(passwd:sub(i, i)); |
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77 if passwd_i > 0x7F then |
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78 i = i + 1; |
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79 local passwd_i_1 = to_byte(passwd:sub(i, i)); |
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80 t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever |
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81 else |
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82 t_insert(p, to_char(passwd_i)); |
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83 end |
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84 i = i + 1; |
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85 end |
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86 return t_concat(p); |
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87 end |
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88 local function latin1toutf8(str) |
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89 local p = {}; |
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90 for ch in s_gmatch(str, ".") do |
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91 ch = to_byte(ch); |
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92 if (ch < 0x80) then |
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93 t_insert(p, to_char(ch)); |
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94 elseif (ch < 0xC0) then |
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95 t_insert(p, to_char(0xC2, ch)); |
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96 else |
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97 t_insert(p, to_char(0xC3, ch - 64)); |
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98 end |
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99 end |
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100 return t_concat(p); |
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101 end |
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102 local function parse(data) |
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103 local message = {} |
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104 for k, v in s_gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder |
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105 message[k] = v; |
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106 end |
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107 return message; |
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108 end |
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109 |
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110 if not self.nonce then |
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111 self.nonce = generate_uuid(); |
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112 self.step = 0; |
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113 self.nonce_count = {}; |
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114 end |
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115 |
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116 self.step = self.step + 1; |
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117 if (self.step == 1) then |
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118 local challenge = serialize({ nonce = self.nonce, |
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119 qop = "auth", |
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120 charset = "utf-8", |
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121 algorithm = "md5-sess", |
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122 realm = self.realm}); |
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123 return "challenge", challenge; |
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124 elseif (self.step == 2) then |
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125 local response = parse(message); |
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126 -- check for replay attack |
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127 if response["nc"] then |
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128 if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end |
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129 end |
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130 |
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131 -- check for username, it's REQUIRED by RFC 2831 |
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132 if not response["username"] then |
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133 return "failure", "malformed-request"; |
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134 end |
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135 self["username"] = response["username"]; |
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136 |
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137 -- check for nonce, ... |
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138 if not response["nonce"] then |
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139 return "failure", "malformed-request"; |
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140 else |
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141 -- check if it's the right nonce |
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142 if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end |
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143 end |
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144 |
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145 if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end |
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146 if not response["qop"] then response["qop"] = "auth" end |
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147 |
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148 if response["realm"] == nil or response["realm"] == "" then |
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149 response["realm"] = ""; |
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150 elseif response["realm"] ~= self.realm then |
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151 return "failure", "not-authorized", "Incorrect realm value"; |
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152 end |
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153 |
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154 local decoder; |
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155 if response["charset"] == nil then |
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156 decoder = utf8tolatin1ifpossible; |
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157 elseif response["charset"] ~= "utf-8" then |
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158 return "failure", "incorrect-encoding", "The client's response uses "..response["charset"].." for encoding with isn't supported by sasl.lua. Supported encodings are latin or utf-8."; |
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159 end |
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160 |
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161 local domain = ""; |
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162 local protocol = ""; |
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163 if response["digest-uri"] then |
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164 protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$"); |
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165 if protocol == nil or domain == nil then return "failure", "malformed-request" end |
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166 else |
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167 return "failure", "malformed-request", "Missing entry for digest-uri in SASL message." |
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168 end |
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169 |
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170 --TODO maybe realm support |
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171 self.username = response["username"]; |
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172 if self.profile.plain then |
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173 local password, state = self.profile.plain(response["username"], self.realm) |
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174 if state == nil then return "failure", "not-authorized" |
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175 elseif state == false then return "failure", "account-disabled" end |
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176 Y = md5(response["username"]..":"..response["realm"]..":"..password); |
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177 elseif self.profile["digest-md5"] then |
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178 local Y, state = self.profile["digest-md5"](response["username"], self.realm, response["realm"], response["charset"]) |
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179 if state == nil then return "failure", "not-authorized" |
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180 elseif state == false then return "failure", "account-disabled" end |
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181 elseif self.profile["digest-md5-test"] then |
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182 -- TODO |
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183 end |
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184 --local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder); |
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185 --if Y == nil then return "failure", "not-authorized" |
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186 --elseif Y == false then return "failure", "account-disabled" end |
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187 local A1 = ""; |
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188 if response.authzid then |
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189 if response.authzid == self.username or response.authzid == self.username.."@"..self.realm then |
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190 -- COMPAT |
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191 log("warn", "Client is violating RFC 3920 (section 6.1, point 7)."); |
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192 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid; |
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193 else |
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194 return "failure", "invalid-authzid"; |
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195 end |
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196 else |
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197 A1 = Y..":"..response["nonce"]..":"..response["cnonce"]; |
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198 end |
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199 local A2 = "AUTHENTICATE:"..protocol.."/"..domain; |
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200 |
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201 local HA1 = md5(A1, true); |
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202 local HA2 = md5(A2, true); |
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203 |
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204 local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2; |
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205 local response_value = md5(KD, true); |
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206 |
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207 if response_value == response["response"] then |
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208 -- calculate rspauth |
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209 A2 = ":"..protocol.."/"..domain; |
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210 |
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211 HA1 = md5(A1, true); |
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212 HA2 = md5(A2, true); |
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213 |
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214 KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2 |
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215 local rspauth = md5(KD, true); |
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216 self.authenticated = true; |
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217 --TODO: considering sending the rspauth in a success node for saving one roundtrip; allowed according to http://tools.ietf.org/html/draft-saintandre-rfc3920bis-09#section-7.3.6 |
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218 return "challenge", serialize({rspauth = rspauth}); |
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219 else |
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220 return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated." |
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221 end |
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222 elseif self.step == 3 then |
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223 if self.authenticated ~= nil then return "success" |
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224 else return "failure", "malformed-request" end |
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225 end |
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226 end |
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227 |
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228 function init(registerMechanism) |
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229 registerMechanism("DIGEST-MD5", {"plain"}, digest); |
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230 end |
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231 |
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232 return _M; |