-- sasl.lua v0.4
-- Copyright (C) 2008-2010 Tobias Markmann
--
--- All rights reserved.
+-- All rights reserved.
--
--- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+-- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
--
--- * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
--- * 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.
--- * 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.
+-- * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+-- * 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.
+-- * 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.
--
--- 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.
+-- 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.
local s_match = string.match;
local type = type
module "scram"
--=========================
---SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
+--SASL SCRAM-SHA-1 according to RFC 5802
--[[
Supported Authentication Backends
-scram-{MECH}:
+scram_{MECH}:
+ -- MECH being a standard hash name (like those at IANA's hash registry) with '-' replaced with '_'
function(username, realm)
- return salted_password, iteration_count, salt, state;
+ return stored_key, server_key, iteration_count, salt, state;
end
]]
end
-- hash algorithm independent Hi(PBKDF2) implementation
-local function Hi(hmac, str, salt, i)
+function Hi(hmac, str, salt, i)
local Ust = hmac(str, salt.."\0\0\0\1");
- local res = Ust;
+ local res = Ust;
for n=1,i-1 do
local Und = hmac(str, Ust)
res = binaryXOR(res, Und)
-- check for forbidden char sequences
for eq in username:gmatch("=(.?.?)") do
if eq ~= "2D" and eq ~= "3D" then
- return false
- end
+ return false
+ end
end
-- replace =2D with , and =3D with =
return username;
end
+local function hashprep(hashname)
+ return hashname:lower():gsub("-", "_");
+end
+
+function getAuthenticationDatabaseSHA1(password, salt, iteration_count)
+ if type(password) ~= "string" or type(salt) ~= "string" or type(iteration_count) ~= "number" then
+ return false, "inappropriate argument types"
+ end
+ if iteration_count < 4096 then
+ log("warn", "Iteration count < 4096 which is the suggested minimum according to RFC 5802.")
+ end
+ local salted_password = Hi(hmac_sha1, password, salt, iteration_count);
+ local stored_key = sha1(hmac_sha1(salted_password, "Client Key"))
+ local server_key = hmac_sha1(salted_password, "Server Key");
+ return true, stored_key, server_key
+end
+
local function scram_gen(hash_name, H_f, HMAC_f)
local function scram_hash(self, message)
if not self.state then self["state"] = {} end
+ if type(message) ~= "string" or #message == 0 then return "failure", "malformed-request" end
if not self.state.name then
-- we are processing client_first_message
local client_first_message = message;
+
+ -- TODO: fail if authzid is provided, since we don't support them yet
self.state["client_first_message"] = client_first_message;
- self.state["name"] = client_first_message:match("n=(.+),r=")
- self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
-
- if not self.state.name or not self.state.clientnonce then
+ self.state["gs2_cbind_flag"], self.state["authzid"], self.state["name"], self.state["clientnonce"]
+ = client_first_message:match("^(%a),(.*),n=(.*),r=([^,]*).*");
+
+ -- we don't do any channel binding yet
+ if self.state.gs2_cbind_flag ~= "n" and self.state.gs2_cbind_flag ~= "y" then
return "failure", "malformed-request";
end
+
+ if not self.state.name or not self.state.clientnonce then
+ return "failure", "malformed-request", "Channel binding isn't support at this time.";
+ end
self.state.name = validate_username(self.state.name);
if not self.state.name then
-- retreive credentials
if self.profile.plain then
- password, state = self.profile.plain(self.state.name, self.realm)
+ local password, state = self.profile.plain(self, self.state.name, self.realm)
if state == nil then return "failure", "not-authorized"
elseif state == false then return "failure", "account-disabled" end
log("debug", "Password violates SASLprep.");
return "failure", "not-authorized", "Invalid password."
end
+
self.state.salt = generate_uuid();
self.state.iteration_count = default_i;
- self.state.salted_password = Hi(HMAC_f, password, self.state.salt, default_i);
- elseif self.profile["scram-"..hash_name] then
- salted_password, iteration_count, salt, state = self.profile["scram-"..hash_name](self.state.name, self.realm);
+
+ local succ = false;
+ succ, self.state.stored_key, self.state.server_key = getAuthenticationDatabaseSHA1(password, self.state.salt, default_i, self.state.iteration_count);
+ if not succ then
+ log("error", "Generating authentication database failed. Reason: %s", self.state.stored_key);
+ return "failure", "temporary-auth-failure";
+ end
+ elseif self.profile["scram_"..hashprep(hash_name)] then
+ local stored_key, server_key, iteration_count, salt, state = self.profile["scram_"..hashprep(hash_name)](self, self.state.name, self.realm);
if state == nil then return "failure", "not-authorized"
elseif state == false then return "failure", "account-disabled" end
- self.state.salted_password = salted_password;
+ self.state.stored_key = stored_key;
+ self.state.server_key = server_key;
self.state.iteration_count = iteration_count;
self.state.salt = salt
end
self.state["server_first_message"] = server_first_message;
return "challenge", server_first_message
else
- if type(message) ~= "string" then return "failure", "malformed-request" end
-- we are processing client_final_message
local client_final_message = message;
-
- self.state["proof"] = client_final_message:match("p=(.+)");
- self.state["nonce"] = client_final_message:match("r=(.+),p=");
- self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
+
+ self.state["channelbinding"], self.state["nonce"], self.state["proof"] = client_final_message:match("^c=(.*),r=(.*),.*p=(.*)");
+
if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
end
-
- local SaltedPassword = self.state.salted_password;
- local ClientKey = HMAC_f(SaltedPassword, "Client Key")
- local ServerKey = HMAC_f(SaltedPassword, "Server Key")
- local StoredKey = H_f(ClientKey)
+
+ if self.state.nonce ~= self.state.clientnonce..self.state.servernonce then
+ return "failure", "malformed-request", "Wrong nonce in client-final-message.";
+ end
+
+ local ServerKey = self.state.server_key;
+ local StoredKey = self.state.stored_key;
+
local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
local ClientSignature = HMAC_f(StoredKey, AuthMessage)
- local ClientProof = binaryXOR(ClientKey, ClientSignature)
+ local ClientKey = binaryXOR(ClientSignature, base64.decode(self.state.proof))
local ServerSignature = HMAC_f(ServerKey, AuthMessage)
-
- if base64.encode(ClientProof) == self.state.proof then
+
+ if StoredKey == H_f(ClientKey) then
local server_final_message = "v="..base64.encode(ServerSignature);
self["username"] = self.state.name;
return "success", server_final_message;
function init(registerMechanism)
local function registerSCRAMMechanism(hash_name, hash, hmac_hash)
- registerMechanism("SCRAM-"..hash_name, {"plain", "scram-"..(hash_name:lower())}, scram_gen(hash_name:lower(), hash, hmac_hash));
+ registerMechanism("SCRAM-"..hash_name, {"plain", "scram_"..(hashprep(hash_name))}, scram_gen(hash_name:lower(), hash, hmac_hash));
end
-
+
registerSCRAMMechanism("SHA-1", sha1, hmac_sha1);
end
-return _M;
\ No newline at end of file
+return _M;
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