-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- Copyright (C) 2010 Jeff Mitchell

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local datamanager = require "util.datamanager";

local log = require "util.logger".init("auth_internal_hashed");

local getAuthenticationDatabaseSHA1 = require "util.sasl.scram".getAuthenticationDatabaseSHA1;

local usermanager = require "core.usermanager";

local generate_uuid = require "util.uuid".generate;

local new_sasl = require "util.sasl".new;

local nodeprep = require "util.encodings".stringprep.nodeprep;

local to_hex;

do

	local function replace_byte_with_hex(byte)

		return ("%02x"):format(byte:byte());

	end

	function to_hex(binary_string)

		return binary_string:gsub(".", replace_byte_with_hex);

	end

end

local from_hex;

do

	local function replace_hex_with_byte(hex)

		return string.char(tonumber(hex, 16));

	end

	function from_hex(hex_string)

		return hex_string:gsub("..", replace_hex_with_byte);

	end

end

-- Default; can be set per-user

local iteration_count = 4096;

function new_hashpass_provider(host)

	local provider = { name = "internal_hashed" };

	log("debug", "initializing internal_hashed authentication provider for host '%s'", host);

	function provider.test_password(username, password)

		local credentials = datamanager.load(username, host, "accounts") or {};

		if credentials.password ~= nil and string.len(credentials.password) ~= 0 then

			if credentials.password ~= password then

				return nil, "Auth failed. Provided password is incorrect.";

			end

			if provider.set_password(username, credentials.password) == nil then

				return nil, "Auth failed. Could not set hashed password from plaintext.";

			else

				return true;

			end

		end

		if credentials.iteration_count == nil or credentials.salt == nil or string.len(credentials.salt) == 0 then

			return nil, "Auth failed. Stored salt and iteration count information is not complete.";

		end

		local valid, stored_key, server_key = getAuthenticationDatabaseSHA1(password, credentials.salt, credentials.iteration_count);

		local stored_key_hex = to_hex(stored_key);

		local server_key_hex = to_hex(server_key);

		if valid and stored_key_hex == credentials.stored_key and server_key_hex == credentials.server_key then

			return true;

		else

			return nil, "Auth failed. Invalid username, password, or password hash information.";

		end

	end

	function provider.set_password(username, password)

		local account = datamanager.load(username, host, "accounts");

		if account then

			account.salt = account.salt or generate_uuid();

			account.iteration_count = account.iteration_count or iteration_count;

			local valid, stored_key, server_key = getAuthenticationDatabaseSHA1(password, account.salt, account.iteration_count);

			local stored_key_hex = to_hex(stored_key);

			local server_key_hex = to_hex(server_key);

			account.stored_key = stored_key_hex

			account.server_key = server_key_hex

			account.password = nil;

			return datamanager.store(username, host, "accounts", account);

		end

		return nil, "Account not available.";

	end

	function provider.user_exists(username)

		local account = datamanager.load(username, host, "accounts");

		if not account then

			log("debug", "account not found for username '%s' at host '%s'", username, module.host);

			return nil, "Auth failed. Invalid username";

		end

		return true;

	end

	function provider.create_user(username, password)

		if password == nil then

			return datamanager.store(username, host, "accounts", {});

		end

		local salt = generate_uuid();

		local valid, stored_key, server_key = getAuthenticationDatabaseSHA1(password, salt, iteration_count);

		local stored_key_hex = to_hex(stored_key);

		local server_key_hex = to_hex(server_key);

		return datamanager.store(username, host, "accounts", {stored_key = stored_key_hex, server_key = server_key_hex, salt = salt, iteration_count = iteration_count});

	end

	function provider.delete_user(username)

		return datamanager.store(username, host, "accounts", nil);

	end

	function provider.get_sasl_handler()

		local testpass_authentication_profile = {

			plain_test = function(sasl, username, password, realm)

				local prepped_username = nodeprep(username);

				if not prepped_username then

					log("debug", "NODEprep failed on username: %s", username);

					return "", nil;

				end

				return usermanager.test_password(prepped_username, realm, password), true;

			end,

			scram_sha_1 = function(sasl, username, realm)

				local credentials = datamanager.load(username, host, "accounts");

				if not credentials then return; end

				if credentials.password then

					usermanager.set_password(username, credentials.password, host);

					credentials = datamanager.load(username, host, "accounts");

					if not credentials then return; end

				end

				local stored_key, server_key, iteration_count, salt = credentials.stored_key, credentials.server_key, credentials.iteration_count, credentials.salt;

				stored_key = stored_key and from_hex(stored_key);

				server_key = server_key and from_hex(server_key);

				return stored_key, server_key, iteration_count, salt, true;

			end

		};

		return new_sasl(module.host, testpass_authentication_profile);

	end

	return provider;

end

module:add_item("auth-provider", new_hashpass_provider(module.host));