-- sasl.lua v0.4
--- Copyright (C) 2008-2010 Tobias Markmann
+-- Copyright (C) 2008-2009 Tobias Markmann
--
-- All rights reserved.
--
--=========================
--SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
-
---[[
-Supported Authentication Backends
-
-scram-{MECH}:
- function(username, realm)
- return salted_password, iteration_count, salt, state;
- end
-]]
-
local default_i = 4096
local function bp( b )
return username;
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
+local function scram_sha_1(self, message)
+ if not self.state then self["state"] = {} end
- if not self.state.name then
- -- we are processing client_first_message
- local client_first_message = message;
- 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 then
+ -- we are processing client_first_message
+ local client_first_message = message;
+ 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
- return "failure", "malformed-request";
- end
+ if not self.state.name or not self.state.clientnonce then
+ return "failure", "malformed-request";
+ end
- self.state.name = validate_username(self.state.name);
- if not self.state.name then
- log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
- return "failure", "malformed-request", "Invalid username.";
- end
+ self.state.name = validate_username(self.state.name);
+ if not self.state.name then
+ log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
+ return "failure", "malformed-request", "Invalid username.";
+ end
- self.state["servernonce"] = generate_uuid();
-
- -- retreive credentials
- if self.profile.plain then
- password, state = self.profile.plain(self.state.name, self.realm)
- if state == nil then return "failure", "not-authorized"
- elseif state == false then return "failure", "account-disabled" end
-
- password = saslprep(password);
- if not password then
- 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);
- 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.iteration_count = iteration_count;
- self.state.salt = salt
- end
+ self.state["servernonce"] = generate_uuid();
+ self.state["salt"] = generate_uuid();
- local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..self.state.iteration_count;
- 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;
+ local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..default_i;
+ 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=");
- 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.";
+ 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=");
+ 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 password, state;
+ if self.profile.plain then
+ password, state = self.profile.plain(self.state.name, self.realm)
+ if state == nil then return "failure", "not-authorized"
+ elseif state == false then return "failure", "account-disabled" end
+ password = saslprep(password);
+ if not password then
+ log("debug", "Password violates SASLprep.");
+ return "failure", "not-authorized", "Invalid password."
end
+ 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)
- 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 ServerSignature = HMAC_f(ServerKey, AuthMessage)
+ local SaltedPassword = Hi(hmac_sha1, password, self.state.salt, default_i)
+ local ClientKey = hmac_sha1(SaltedPassword, "Client Key")
+ local ServerKey = hmac_sha1(SaltedPassword, "Server Key")
+ local StoredKey = sha1(ClientKey)
+ 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_sha1(StoredKey, AuthMessage)
+ local ClientProof = binaryXOR(ClientKey, ClientSignature)
+ local ServerSignature = hmac_sha1(ServerKey, AuthMessage)
- if base64.encode(ClientProof) == self.state.proof then
- local server_final_message = "v="..base64.encode(ServerSignature);
- self["username"] = self.state.name;
- return "success", server_final_message;
- else
- return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
- end
+ if base64.encode(ClientProof) == self.state.proof then
+ local server_final_message = "v="..base64.encode(ServerSignature);
+ self["username"] = self.state.name;
+ return "success", server_final_message;
+ else
+ return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
end
end
- return scram_hash;
end
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));
- end
-
- registerSCRAMMechanism("SHA-1", sha1, hmac_sha1);
+ registerMechanism("SCRAM-SHA-1", {"plain"}, scram_sha_1);
end
return _M;
\ No newline at end of file
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