File

mod_s2s_auth_fingerprint/mod_s2s_auth_fingerprint.lua @ 5193:2bb29ece216b

mod_http_oauth2: Implement stateless dynamic client registration Replaces previous explicit registration that required either the additional module mod_adhoc_oauth2_client or manually editing the database. That method was enough to have something to test with, but would not probably not scale easily. Dynamic client registration allows creating clients on the fly, which may be even easier in theory. In order to not allow basically unauthenticated writes to the database, we implement a stateless model here. per_host_key := HMAC(config -> oauth2_registration_key, hostname) client_id := JWT { client metadata } signed with per_host_key client_secret := HMAC(per_host_key, client_id) This should ensure everything we need to know is part of the client_id, allowing redirects etc to be validated, and the client_secret can be validated with only the client_id and the per_host_key. A nonce injected into the client_id JWT should ensure nobody can submit the same client metadata and retrieve the same client_secret
author Kim Alvefur <zash@zash.se>
date Fri, 03 Mar 2023 21:14:19 +0100
parent 1875:ee2cedb0f691
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-- Copyright (C) 2013-2014 Kim Alvefur
-- This file is MIT/X11 licensed.

module:set_global();

local digest_algo = module:get_option_string(module:get_name().."_digest", "sha1");

local fingerprints = {};

local function hashprep(h)
	return tostring(h):gsub(":",""):lower();
end

local function hashfmt(h)
	return h:gsub("..","%0:", #h/2-1):upper();
end

for host, set in pairs(module:get_option("s2s_trusted_fingerprints", {})) do
	local host_set = {}
	if type(set) == "table" then -- list of fingerprints
		for i=1,#set do
			host_set[hashprep(set[i])] = true;
		end
	else -- assume single fingerprint
		host_set[hashprep(set)] = true;
	end
	fingerprints[host] = host_set;
end

module:hook("s2s-check-certificate", function(event)
	local session, host, cert = event.session, event.host, event.cert;

	local host_fingerprints = fingerprints[host];
	if host_fingerprints then
		local digest = cert and cert:digest(digest_algo);
		if host_fingerprints[digest] then
			module:log("info", "'%s' matched %s fingerprint %s", host, digest_algo:upper(), hashfmt(digest));
			session.cert_chain_status = "valid";
			session.cert_identity_status = "valid";
			return true;
		else
			module:log("warn", "'%s' has unknown %s fingerprint %s", host, digest_algo:upper(), hashfmt(digest));
			session.cert_chain_status = "invalid";
			session.cert_identity_status = "invalid";
		end
	end
end);