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plugins/mod_auth_internal_plain.lua @ 13801:a5d5fefb8b68 13.0

mod_tls: Enable Prosody's certificate checking for incoming s2s connections (fixes #1916) (thanks Damian, Zash) Various options in Prosody allow control over the behaviour of the certificate verification process For example, some deployments choose to allow falling back to traditional "dialback" authentication (XEP-0220), while others verify via DANE, hard-coded fingerprints, or other custom plugins. Implementing this flexibility requires us to override OpenSSL's default certificate verification, to allow Prosody to verify the certificate itself, apply custom policies and make decisions based on the outcome. To enable our custom logic, we have to suppress OpenSSL's default behaviour of aborting the connection with a TLS alert message. With LuaSec, this can be achieved by using the verifyext "lsec_continue" flag. We also need to use the lsec_ignore_purpose flag, because XMPP s2s uses server certificates as "client" certificates (for mutual TLS verification in outgoing s2s connections). Commit 99d2100d2918 moved these settings out of the defaults and into mod_s2s, because we only really need these changes for s2s, and they should be opt-in, rather than automatically applied to all TLS services we offer. That commit was incomplete, because it only added the flags for incoming direct TLS connections. StartTLS connections are handled by mod_tls, which was not applying the lsec_* flags. It previously worked because they were already in the defaults. This resulted in incoming s2s connections with "invalid" certificates being aborted early by OpenSSL, even if settings such as `s2s_secure_auth = false` or DANE were present in the config. Outgoing s2s connections inherit verify "none" from the defaults, which means OpenSSL will receive the cert but will not terminate the connection when it is deemed invalid. This means we don't need lsec_continue there, and we also don't need lsec_ignore_purpose (because the remote peer is a "server"). Wondering why we can't just use verify "none" for incoming s2s? It's because in that mode, OpenSSL won't request a certificate from the peer for incoming connections. Setting verify "peer" is how you ask OpenSSL to request a certificate from the client, but also what triggers its built-in verification.
author Matthew Wild <mwild1@gmail.com>
date Tue, 01 Apr 2025 17:26:56 +0100
parent 13506:1b81a7b7c9b8
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local usermanager = require "prosody.core.usermanager";
local new_sasl = require "prosody.util.sasl".new;
local saslprep = require "prosody.util.encodings".stringprep.saslprep;
local secure_equals = require "prosody.util.hashes".equals;

local log = module._log;
local host = module.host;

local accounts = module:open_store("accounts");

-- define auth provider
local provider = {};

function provider.test_password(username, password)
	log("debug", "test password for user '%s'", username);
	local credentials = accounts:get(username) or {};
	if credentials.disabled then
		return nil, "Account disabled.";
	end
	password = saslprep(password);
	if not password then
		return nil, "Password fails SASLprep.";
	end

	if secure_equals(password, saslprep(credentials.password)) then
		return true;
	else
		return nil, "Auth failed. Invalid username or password.";
	end
end

function provider.get_password(username)
	log("debug", "get_password for username '%s'", username);
	return (accounts:get(username) or {}).password;
end

function provider.set_password(username, password)
	log("debug", "set_password for username '%s'", username);
	password = saslprep(password);
	if not password then
		return nil, "Password fails SASLprep.";
	end
	local account = accounts:get(username);
	if account then
		account.password = password;
		account.updated = os.time();
		return accounts:set(username, account);
	end
	return nil, "Account not available.";
end

function provider.get_account_info(username)
	local account = accounts:get(username);
	if not account then return nil, "Account not available"; end
	return {
		created = account.created;
		password_updated = account.updated;
	};
end

function provider.user_exists(username)
	local account = accounts:get(username);
	if not account then
		log("debug", "account not found for username '%s'", username);
		return nil, "Auth failed. Invalid username";
	end
	return true;
end

function provider.users()
	return accounts:users();
end

function provider.create_user(username, password)
	local now = os.time();
	if password == nil then
		return accounts:set(username, { created = now, updated = now, disabled = true });
	end
	password = saslprep(password);
	if not password then
		return nil, "Password fails SASLprep.";
	end
	return accounts:set(username, {
		password = password;
		created = now, updated = now;
	});
end

function provider.delete_user(username)
	return accounts:set(username, nil);
end

function provider.get_sasl_handler()
	local getpass_authentication_profile = {
		plain = function(_, username, realm)
			local password = usermanager.get_password(username, realm);
			if not password then
				return "", nil;
			end
			return password, true;
		end
	};
	return new_sasl(host, getpass_authentication_profile);
end

module:provides("auth", provider);