jiti-meet/resources/prosody-plugins/token/util.lib.lua

377 lines
14 KiB
Lua

-- Token authentication
-- Copyright (C) 2015 Atlassian
local basexx = require "basexx";
local have_async, async = pcall(require, "util.async");
local hex = require "util.hex";
local jwt = require "luajwtjitsi";
local http = require "net.http";
local jid = require "util.jid";
local json = require "cjson";
local path = require "util.paths";
local sha256 = require "util.hashes".sha256;
local timer = require "util.timer";
local http_timeout = 30;
local http_headers = {
["User-Agent"] = "Prosody ("..prosody.version.."; "..prosody.platform..")"
};
-- TODO: Figure out a less arbitrary default cache size.
local cacheSize = module:get_option_number("jwt_pubkey_cache_size", 128);
local cache = require"util.cache".new(cacheSize);
local Util = {}
Util.__index = Util
--- Constructs util class for token verifications.
-- Constructor that uses the passed module to extract all the
-- needed configurations.
-- If confuguration is missing returns nil
-- @param module the module in which options to check for configs.
-- @return the new instance or nil
function Util.new(module)
local self = setmetatable({}, Util)
self.appId = module:get_option_string("app_id");
self.appSecret = module:get_option_string("app_secret");
self.asapKeyServer = module:get_option_string("asap_key_server");
self.allowEmptyToken = module:get_option_boolean("allow_empty_token");
--[[
Multidomain can be supported in some deployments. In these deployments
there is a virtual conference muc, which address contains the subdomain
to use. Those deployments are accessible
by URL https://domain/subdomain.
Then the address of the room will be:
roomName@conference.subdomain.domain. This is like a virtual address
where there is only one muc configured by default with address:
conference.domain and the actual presentation of the room in that muc
component is [subdomain]roomName@conference.domain.
These setups relay on configuration 'muc_domain_base' which holds
the main domain and we use it to substract subdomains from the
virtual addresses.
The following confgurations are for multidomain setups and domain name
verification:
--]]
-- optional parameter for custom muc component prefix,
-- defaults to "conference"
self.muc_domain_prefix = module:get_option_string(
"muc_mapper_domain_prefix", "conference");
-- domain base, which is the main domain used in the deployment,
-- the main VirtualHost for the deployment
self.muc_domain_base = module:get_option_string("muc_mapper_domain_base");
-- The "real" MUC domain that we are proxying to
if self.muc_domain_base then
self.muc_domain = module:get_option_string(
"muc_mapper_domain",
self.muc_domain_prefix.."."..self.muc_domain_base);
end
-- whether domain name verification is enabled, by default it is disabled
self.enableDomainVerification = module:get_option_boolean(
"enable_domain_verification", false);
if self.allowEmptyToken == true then
module:log("warn", "WARNING - empty tokens allowed");
end
if self.appId == nil then
module:log("error", "'app_id' must not be empty");
return nil;
end
if self.appSecret == nil and self.asapKeyServer == nil then
module:log("error", "'app_secret' or 'asap_key_server' must be specified");
return nil;
end
--array of accepted issuers: by default only includes our appId
self.acceptedIssuers = module:get_option_array('asap_accepted_issuers',{self.appId})
--array of accepted audiences: by default only includes our appId
self.acceptedAudiences = module:get_option_array('asap_accepted_audiences',{'*'})
if self.asapKeyServer and not have_async then
module:log("error", "requires a version of Prosody with util.async");
return nil;
end
return self
end
--- Returns the public key by keyID
-- @param keyId the key ID to request
-- @return the public key (the content of requested resource) or nil
function Util:get_public_key(keyId)
local content = cache:get(keyId);
if content == nil then
-- If the key is not found in the cache.
module:log("debug", "Cache miss for key: "..keyId);
local code;
local wait, done = async.waiter();
local function cb(content_, code_, response_, request_)
content, code = content_, code_;
if code == 200 or code == 204 then
cache:set(keyId, content);
end
done();
end
local keyurl = path.join(self.asapKeyServer, hex.to(sha256(keyId))..'.pem');
module:log("debug", "Fetching public key from: "..keyurl);
-- We hash the key ID to work around some legacy behavior and make
-- deployment easier. It also helps prevent directory
-- traversal attacks (although path cleaning could have done this too).
local request = http.request(keyurl, {
headers = http_headers or {},
method = "GET"
}, cb);
-- TODO: Is the done() call racey? Can we cancel this if the request
-- succeedes?
local function cancel()
-- TODO: This check is racey. Not likely to be a problem, but we should
-- still stick a mutex on content / code at some point.
if code == nil then
http.destroy_request(request);
done();
end
end
timer.add_task(http_timeout, cancel);
wait();
if code == 200 or code == 204 then
return content;
end
else
-- If the key is in the cache, use it.
module:log("debug", "Cache hit for key: "..keyId);
return content;
end
return nil;
end
--- Verifies issuer part of token
-- @param 'iss' claim from the token to verify
-- @return nil and error string or true for accepted claim
function Util:verify_issuer(issClaim)
for i, iss in ipairs(self.acceptedIssuers) do
if issClaim == iss then
--claim matches an accepted issuer so return success
return true;
end
end
--if issClaim not found in acceptedIssuers, fail claim
return nil, "Invalid issuer ('iss' claim)";
end
--- Verifies audience part of token
-- @param 'aud' claim from the token to verify
-- @return nil and error string or true for accepted claim
function Util:verify_audience(audClaim)
for i, aud in ipairs(self.acceptedAudiences) do
if aud == '*' then
--* indicates to accept any audience in the claims so return success
return true;
end
if audClaim == aud then
--claim matches an accepted audience so return success
return true;
end
end
--if issClaim not found in acceptedIssuers, fail claim
return nil, "Invalid audience ('aud' claim)";
end
--- Verifies token
-- @param token the token to verify
-- @param secret the secret to use to verify token
-- @return nil and error or the extracted claims from the token
function Util:verify_token(token, secret)
local claims, err = jwt.decode(token, secret, true);
if claims == nil then
return nil, err;
end
local alg = claims["alg"];
if alg ~= nil and (alg == "none" or alg == "") then
return nil, "'alg' claim must not be empty";
end
local issClaim = claims["iss"];
if issClaim == nil then
return nil, "'iss' claim is missing";
end
--check the issuer against the accepted list
local issCheck, issCheckErr = self:verify_issuer(issClaim);
if issCheck == nil then
return nil, issCheckErr;
end
local roomClaim = claims["room"];
if roomClaim == nil then
return nil, "'room' claim is missing";
end
local audClaim = claims["aud"];
if audClaim == nil then
return nil, "'aud' claim is missing";
end
--check the audience against the accepted list
local audCheck, audCheckErr = self:verify_audience(audClaim);
if audCheck == nil then
return nil, audCheckErr;
end
return claims;
end
--- Verifies token and process needed values to be stored in the session.
-- Token is obtained from session.auth_token.
-- Stores in session the following values:
-- session.jitsi_meet_room - the room name value from the token
-- session.jitsi_meet_domain - the domain name value from the token
-- session.jitsi_meet_context_user - the user details from the token
-- session.jitsi_meet_context_group - the group value from the token
-- @param session the current session
-- @return false and error
function Util:process_and_verify_token(session)
if session.auth_token == nil then
if self.allowEmptyToken then
return true;
else
return false, "not-allowed", "token required";
end
end
local pubKey;
if self.asapKeyServer and session.auth_token ~= nil then
local dotFirst = session.auth_token:find("%.");
if not dotFirst then return nil, "Invalid token" end
local header = json.decode(basexx.from_url64(session.auth_token:sub(1,dotFirst-1)));
local kid = header["kid"];
if kid == nil then
return false, "not-allowed", "'kid' claim is missing";
end
pubKey = self:get_public_key(kid);
if pubKey == nil then
return false, "not-allowed", "could not obtain public key";
end
end
-- now verify the whole token
local claims, msg;
if self.asapKeyServer then
claims, msg = self:verify_token(session.auth_token, pubKey);
else
claims, msg = self:verify_token(session.auth_token, self.appSecret);
end
if claims ~= nil then
-- Binds room name to the session which is later checked on MUC join
session.jitsi_meet_room = claims["room"];
-- Binds domain name to the session
session.jitsi_meet_domain = claims["sub"];
-- Binds the user details to the session if available
if claims["context"] ~= nil then
if claims["context"]["user"] ~= nil then
session.jitsi_meet_context_user = claims["context"]["user"];
end
if claims["context"]["group"] ~= nil then
-- Binds any group details to the session
session.jitsi_meet_context_group = claims["context"]["group"];
end
end
return true;
else
return false, "not-allowed", msg;
end
end
--- Verifies room name and domain if necesarry.
-- Checks configs and if necessary checks the room name extracted from
-- room_address against the one saved in the session when token was verified.
-- Also verifies domain name from token against the domain in the room_address,
-- if enableDomainVerification is enabled.
-- @param session the current session
-- @param room_address the whole room address as received
-- @return returns true in case room was verified or there is no need to verify
-- it and returns false in case verification was processed
-- and was not successful
function Util:verify_room(session, room_address)
if self.allowEmptyToken and session.auth_token == nil then
module:log(
"debug",
"Skipped room token verification - empty tokens are allowed");
return true;
end
-- extract room name using all chars, except the not allowed ones
local room,_,_ = jid.split(room_address);
if room == nil then
log("error",
"Unable to get name of the MUC room ? to: %s", room_address);
return true;
end
local auth_room = session.jitsi_meet_room;
if not self.enableDomainVerification then
-- if auth_room is missing, this means user is anonymous (no token for
-- its domain) we let it through, jicofo is verifying creation domain
if auth_room and room ~= string.lower(auth_room) and auth_room ~= '*' then
return false;
end
return true;
end
local room_address_to_verify = jid.bare(room_address);
local room_node = jid.node(room_address);
-- parses bare room address, for multidomain expected format is:
-- [subdomain]roomName@conference.domain
local target_subdomain, target_room = room_node:match("^%[([^%]]+)%](.+)$");
-- if we have '*' as room name in token, this means all rooms are allowed
-- so we will use the actual name of the room when constructing strings
-- to verify subdomains and domains to simplify checks
local room_to_check;
if auth_room == '*' then
-- authorized for accessing any room assign to room_to_check the actual
-- room name
if target_room ~= nil then
-- we are in multidomain mode and we were able to extract room name
room_to_check = target_room;
else
-- no target_room, room_address_to_verify does not contain subdomain
-- so we get just the node which is the room name
room_to_check = room_node;
end
else
room_to_check = auth_room;
end
local auth_domain = session.jitsi_meet_domain;
if target_subdomain then
-- from this point we depend on muc_domain_base,
-- deny access if option is missing
if not self.muc_domain_base then
module:log("warn", "No 'muc_domain_base' option set, denying access!");
return false;
end
return room_address_to_verify == jid.join(
"["..auth_domain.."]"..string.lower(room_to_check), self.muc_domain);
else
-- we do not have a domain part (multidomain is not enabled)
-- verify with info from the token
return room_address_to_verify == jid.join(
string.lower(room_to_check), self.muc_domain_prefix.."."..auth_domain);
end
end
return Util;