local base64 = require "util.encodings".base64;
local hmac_sha1 = require "util.hashes".hmac_sha1;
local sha1 = require "util.hashes".sha1;
+local Hi = require "util.hashes".scram_Hi_sha1;
local generate_uuid = require "util.uuid".generate;
local saslprep = require "util.encodings".stringprep.saslprep;
local nodeprep = require "util.encodings".stringprep.nodeprep;
return t_concat(result);
end
--- hash algorithm independent Hi(PBKDF2) implementation
-function Hi(hmac, str, salt, i)
- local Ust = hmac(str, salt.."\0\0\0\1");
- local res = Ust;
- for n=1,i-1 do
- local Und = hmac(str, Ust)
- res = binaryXOR(res, Und)
- Ust = Und
- end
- return res
-end
-
local function validate_username(username, _nodeprep)
-- check for forbidden char sequences
for eq in username:gmatch("=(.?.?)") do
return false
end
end
-
+
-- replace =2C with , and =3D with =
username = username:gsub("=2C", ",");
username = username:gsub("=3D", "=");
-
+
-- apply SASLprep
username = saslprep(username);
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 salted_password = Hi(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
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["gs2_cbind_flag"], self.state["authzid"], self.state["name"], self.state["clientnonce"]
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, self.profile.nodeprep);
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
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
-
+
password = saslprep(password);
if not password then
log("debug", "Password violates SASLprep.");
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.stored_key = stored_key;
self.state.server_key = server_key;
self.state.iteration_count = iteration_count;
self.state.salt = salt
end
-
+
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
-- we are processing client_final_message
local client_final_message = message;
-
+
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
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 ClientKey = binaryXOR(ClientSignature, base64.decode(self.state.proof))