util/sasl_cyrus.lua

   1 -- sasl.lua v0.4
   2 -- Copyright (C) 2008-2009 Tobias Markmann
   3 --
   4 --    All rights reserved.
   5 --
   6 --    Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
   7 --
   8 --        * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
   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.
  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.
  11 --
  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.
  13
  14 local cyrussasl = require "cyrussasl";
  15 local log = require "util.logger".init("sasl_cyrus");
  16
  17 local setmetatable = setmetatable
  18
  19 local pcall = pcall
  20 local s_match, s_gmatch = string.match, string.gmatch
  21
  22 local sasl_errstring = {
  23         -- SASL result codes --
  24         [1]   = "another step is needed in authentication";
  25         [0]   = "successful result";
  26         [-1]  = "generic failure";
  27         [-2]  = "memory shortage failure";
  28         [-3]  = "overflowed buffer";
  29         [-4]  = "mechanism not supported";
  30         [-5]  = "bad protocol / cancel";
  31         [-6]  = "can't request info until later in exchange";
  32         [-7]  = "invalid parameter supplied";
  33         [-8]  = "transient failure (e.g., weak key)";
  34         [-9]  = "integrity check failed";
  35         [-12] = "SASL library not initialized";
  36
  37         -- client only codes --
  38         [2]   = "needs user interaction";
  39         [-10] = "server failed mutual authentication step";
  40         [-11] = "mechanism doesn't support requested feature";
  41
  42         -- server only codes --
  43         [-13] = "authentication failure";
  44         [-14] = "authorization failure";
  45         [-15] = "mechanism too weak for this user";
  46         [-16] = "encryption needed to use mechanism";
  47         [-17] = "One time use of a plaintext password will enable requested mechanism for user";
  48         [-18] = "passphrase expired, has to be reset";
  49         [-19] = "account disabled";
  50         [-20] = "user not found";
  51         [-23] = "version mismatch with plug-in";
  52         [-24] = "remote authentication server unavailable";
  53         [-26] = "user exists, but no verifier for user";
  54
  55         -- codes for password setting --
  56         [-21] = "passphrase locked";
  57         [-22] = "requested change was not needed";
  58         [-27] = "passphrase is too weak for security policy";
  59         [-28] = "user supplied passwords not permitted";
  60 };
  61 setmetatable(sasl_errstring, { __index = function() return "undefined error!" end });
  62
  63 local _ENV = nil;
  64 -- luacheck: std none
  65
  66 local method = {};
  67 method.__index = method;
  68 local initialized = false;
  69
  70 local function init(service_name)
  71         if not initialized then
  72                 local st, errmsg = pcall(cyrussasl.server_init, service_name);
  73                 if st then
  74                         initialized = true;
  75                 else
  76                         log("error", "Failed to initialize Cyrus SASL: %s", errmsg);
  77                 end
  78         end
  79 end
  80
  81 -- create a new SASL object which can be used to authenticate clients
  82 -- host_fqdn may be nil in which case gethostname() gives the value.
  83 --      For GSSAPI, this determines the hostname in the service ticket (after
  84 --      reverse DNS canonicalization, only if [libdefaults] rdns = true which
  85 --      is the default).
  86 local function new(realm, service_name, app_name, host_fqdn)
  87
  88         init(app_name or service_name);
  89
  90         local st, ret = pcall(cyrussasl.server_new, service_name, host_fqdn, realm, nil, nil)
  91         if not st then
  92                 log("error", "Creating SASL server connection failed: %s", ret);
  93                 return nil;
  94         end
  95
  96         local sasl_i = { realm = realm, service_name = service_name, cyrus = ret };
  97
  98         if cyrussasl.set_canon_cb then
  99                 local c14n_cb = function (user)
 100                         local node = s_match(user, "^([^@]+)");
 101                         log("debug", "Canonicalizing username %s to %s", user, node)
 102                         return node
 103                 end
 104                 cyrussasl.set_canon_cb(sasl_i.cyrus, c14n_cb);
 105         end
 106
 107         cyrussasl.setssf(sasl_i.cyrus, 0, 0xffffffff)
 108         local mechanisms = {};
 109         local cyrus_mechs = cyrussasl.listmech(sasl_i.cyrus, nil, "", " ", "");
 110         for w in s_gmatch(cyrus_mechs, "[^ ]+") do
 111                 mechanisms[w] = true;
 112         end
 113         sasl_i.mechs = mechanisms;
 114         return setmetatable(sasl_i, method);
 115 end
 116
 117 -- get a fresh clone with the same realm and service name
 118 function method:clean_clone()
 119         return new(self.realm, self.service_name)
 120 end
 121
 122 -- get a list of possible SASL mechanims to use
 123 function method:mechanisms()
 124         return self.mechs;
 125 end
 126
 127 -- select a mechanism to use
 128 function method:select(mechanism)
 129         if not self.selected and self.mechs[mechanism] then
 130                 self.selected = mechanism;
 131                 return true;
 132         end
 133 end
 134
 135 -- feed new messages to process into the library
 136 function method:process(message)
 137         local err;
 138         local data;
 139
 140         if not self.first_step_done then
 141                 err, data = cyrussasl.server_start(self.cyrus, self.selected, message or "")
 142                 self.first_step_done = true;
 143         else
 144                 err, data = cyrussasl.server_step(self.cyrus, message or "")
 145         end
 146
 147         self.username = cyrussasl.get_username(self.cyrus)
 148
 149         if (err == 0) then -- SASL_OK
 150                 if self.require_provisioning and not self.require_provisioning(self.username) then
 151                         return "failure", "not-authorized", "User authenticated successfully, but not provisioned for XMPP";
 152                 end
 153                 return "success", data
 154         elseif (err == 1) then -- SASL_CONTINUE
 155                 return "challenge", data
 156         elseif (err == -4) then -- SASL_NOMECH
 157                 log("debug", "SASL mechanism not available from remote end")
 158                 return "failure", "invalid-mechanism", "SASL mechanism not available"
 159         elseif (err == -13) then -- SASL_BADAUTH
 160                 return "failure", "not-authorized", sasl_errstring[err];
 161         else
 162                 log("debug", "Got SASL error condition %d: %s", err, sasl_errstring[err]);
 163                 return "failure", "undefined-condition", sasl_errstring[err];
 164         end
 165 end
 166
 167 return {
 168         new = new;
 169 };