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% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License. You may obtain a copy of
% the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
-module(jwtf_keystore).
-behaviour(gen_server).
-behaviour(config_listener).
-include_lib("public_key/include/public_key.hrl").
% public api.
-export([
get/2,
start_link/0
]).
% gen_server api.
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
code_change/3, terminate/2]).
% config_listener api
-export([handle_config_change/5, handle_config_terminate/3]).
% public functions
get(Alg, undefined) when is_binary(Alg) ->
get(Alg, <<"_default">>);
get(Alg, KID0) when is_binary(Alg), is_binary(KID0) ->
Kty = kty(Alg),
KID = binary_to_list(KID0),
case ets:lookup(?MODULE, {Kty, KID}) of
[] ->
Key = get_from_config(Kty, KID),
ok = gen_server:call(?MODULE, {set, Kty, KID, Key}),
Key;
[{{Kty, KID}, Key}] ->
Key
end.
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
% gen_server functions
init(_) ->
ok = config:listen_for_changes(?MODULE, nil),
ets:new(?MODULE, [public, named_table]),
{ok, nil}.
handle_call({set, Kty, KID, Key}, _From, State) ->
true = ets:insert(?MODULE, {{Kty, KID}, Key}),
{reply, ok, State}.
handle_cast({delete, Kty, KID}, State) ->
true = ets:delete(?MODULE, {Kty, KID}),
{noreply, State};
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info(restart_config_listener, State) ->
ok = config:listen_for_changes(?MODULE, nil),
{noreply, State};
handle_info(_Msg, State) ->
{noreply, State}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
% config listener callback
handle_config_change("jwt_keys", ConfigKey, _ConfigValue, _, _) ->
case string:split(ConfigKey, ":") of
[Kty, KID] ->
gen_server:cast(?MODULE, {delete, Kty, KID});
_ ->
ignored
end,
{ok, nil};
handle_config_change(_, _, _, _, _) ->
{ok, nil}.
handle_config_terminate(_Server, stop, _State) ->
ok;
handle_config_terminate(_Server, _Reason, _State) ->
erlang:send_after(100, whereis(?MODULE), restart_config_listener).
% private functions
get_from_config(Kty, KID) ->
case config:get("jwt_keys", string:join([Kty, KID], ":")) of
undefined ->
throw({bad_request, <<"Unknown kid">>});
Encoded ->
case Kty of
"hmac" ->
try
base64:decode(Encoded)
catch
error:_ ->
throw({bad_request, <<"Not a valid key">>})
end;
"rsa" ->
case pem_decode(Encoded) of
#'RSAPublicKey'{} = Key ->
Key;
_ ->
throw({bad_request, <<"not an RSA public key">>})
end;
"ec" ->
case pem_decode(Encoded) of
{#'ECPoint'{}, _} = Key ->
Key;
_ ->
throw({bad_request, <<"not an EC public key">>})
end
end
end.
pem_decode(PEM) ->
BinPEM = re:replace(PEM, "\\\\n", "\n", [global, {return, binary}]),
try
case public_key:pem_decode(BinPEM) of
[PEMEntry] ->
public_key:pem_entry_decode(PEMEntry);
_ ->
throw({bad_request, <<"Not a valid key">>})
end
catch
error:_ ->
throw({bad_request, <<"Not a valid key">>})
end.
kty(<<"HS", _/binary>>) ->
"hmac";
kty(<<"RS", _/binary>>) ->
"rsa";
kty(<<"ES", _/binary>>) ->
"ec";
kty(_) ->
throw({bad_request, <<"Unknown kty">>}).
|
