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%%% Copyright (c) 2019, Sunet.
%%% See LICENSE for licensing information.
%% Spawn an Erlang port running a proxy app. We use the 'remote'
%% program from p11-kit as the proxy app.
%% Receive PKCS#11 requests from a p11p_server, forward them to the
%% proxy app, wait for a reply. If a reply is received within a
%% timeout period, proxy the reply to the requesting p11p_server. If
%% the request times out, inform the manager (our parent) and exit.
%% Track a subset of the PKCS#11 state in order to handle token
%% restarts. We start in state 'started'. While in 'started', we allow
%% only a few "opening" calls (Initialize, OpenSession and Login)
%% through to the token. Corresponding "closing" calls (Finalize,
%% CloseSession and Logout) are sent an immediate OK response without
%% forwarding them to the token. Any other call is rejected by
%% responding with an error. This should make well behaving P11
%% applications be able to deal with us switching the token under
%% their feet.
-module(p11p_client).
-behaviour(gen_server).
%% API.
-export([start_link/6]).
-export([request/2, % Request from p11p-server.
stop/2]). % Manager stopping us.
-include("p11p_rpc.hrl").
%% Genserver callbacks.
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
code_change/3]).
%% Records and types.
-type token_state() :: started |
initialized |
session |
loggedin |
opact |
finalized.
-record(state, {
token :: string(), % Token name.
timeout :: non_neg_integer(),
port :: port(),
replyto :: pid() | undefined,
p11state = started :: token_state(),
timer :: reference() | undefined,
response :: p11rpc:msg() | undefined,
recv_count = 0 :: non_neg_integer(),
send_count = 0 :: non_neg_integer()
}).
%% API.
-spec start_link(atom(), string(), pid(), string(), list(),
non_neg_integer()) -> {ok, pid()} | {error, term()}.
start_link(ServName, TokName, Server, ModPath, ModEnv, Timeout) ->
lager:info("~p: starting p11p_client for ~s", [self(), TokName]),
gen_server:start_link({local, ServName}, ?MODULE,
[TokName, Server, ModPath, ModEnv, Timeout], []).
-spec request(pid(), p11rpc_msg()) -> ack | nack | {ok, non_neg_integer()}.
request(Client, Request) ->
gen_server:call(Client, {request, Request}).
%% You should invoke stop/1 instead of gen_server:stop/1 if you're
%% uncertain whether we (Pid) are alive or not. An example of when
%% that can happen is when the manager receives a server_event about a
%% lost P11 app -- if the server process terminated on request from us
%% because we timed out on an RPC call, chances are that we have
%% already terminated by the time the manager acts on the information
%% about the lost app.
stop(Pid, Reason) ->
gen_server:cast(Pid, {stop, Reason}).
%% Genserver callbacks.
init([TokName, Server, ModPath, ModEnv, Timeout]) ->
ProxyAppBinPath = p11p_config:proxyapp_bin_path(),
Port = open_port({spawn_executable, ProxyAppBinPath},
[stream,
exit_status,
{env, ModEnv},
{args, [ModPath, "-v"]} % FIXME: Remove -v
]),
true = is_port(Port),
lager:debug("~p: ~s: new proxy app port: ~p", [self(), ProxyAppBinPath, Port]),
lager:debug("~p: ~s: module: ~s, env: ~p", [self(), ProxyAppBinPath, ModPath, ModEnv]),
{ok, #state{port = Port,
token = TokName,
replyto = Server,
timeout = Timeout}}.
handle_call({request, Request},
{FromPid, _Tag},
State = #state{port = Port, send_count = Sent}) ->
case
case State#state.p11state of
started ->
case p11p_rpc:req_id(Request) of
?P11_RPC_CALL_C_Logout -> ack;
?P11_RPC_CALL_C_CloseSession -> ack;
?P11_RPC_CALL_C_Finalize -> ack;
?P11_RPC_CALL_C_Initialize -> pass;
?P11_RPC_CALL_C_OpenSession -> pass;
?P11_RPC_CALL_C_Login -> pass;
_ -> nack
end;
_ ->
pass
end
of
ack ->
{reply, ack, State};
nack ->
{reply, nack, State};
pass ->
lager:debug("~p: sending request from ~p to prxoy app ~p", [self(), FromPid, Port]),
D = p11p_rpc:serialise(Request),
Buf = case Sent of
0 -> <<?RPC_VERSION:8, D/binary>>;
_ -> D
end,
{ok, _} = do_send(Port, Buf),
{reply,
{ok, size(Buf)},
State#state{replyto = FromPid,
timer = start_timer(State#state.timeout, Port),
send_count = Sent + 1}}
end;
handle_call(Call, _From, State) ->
lager:debug("~p: Unhandled call: ~p~n", [self(), Call]),
{reply, unhandled, State}.
handle_cast({stop, Reason}, State) ->
{stop, Reason, State};
handle_cast(Cast, State) ->
lager:debug("~p: unhandled cast: ~p~n", [self(), Cast]),
{noreply, State}.
%% Receiving the very first octets from proxy app since it was started.
handle_info({Port, {data, Data}}, State)
when Port == State#state.port, State#state.response == undefined ->
case hd(Data) of % First octet is RPC protocol version.
?RPC_VERSION ->
NewState = response_in(State, p11p_rpc:new(), tl(Data)),
{noreply, NewState};
BadVersion ->
lager:info("~p: ~p: invalid RPC version: ~p", [self(), Port,
BadVersion]),
{noreply, State}
end;
%% Receiving more data from proxy app.
handle_info({Port, {data, Data}}, State)
when Port == State#state.port ->
NewState = response_in(State, State#state.response, Data),
{noreply, NewState};
%% Proxy app timed out.
handle_info({timeout, Timer, Port}, State)
when Port == State#state.port, Timer == State#state.timer ->
lager:info("~p: rpc request for ~s timed out, exiting", [self(), State#state.token]),
p11p_manager:client_event(timeout, State#state.token),
NewState = State#state{timer = undefined},
{stop, normal, NewState};
handle_info(Info, State) ->
lager:debug("~p: Unhandled info: ~p~n", [self(), Info]),
{noreply, State}.
terminate(Reason, #state{port = Port}) ->
lager:debug("~p: client terminating with reason ~p", [self(), Reason]),
port_close(Port),
ok.
code_change(_OldVersion, State, _Extra) ->
{ok, State}.
%% Private
send_request(Port, Buf) ->
Rand = rand:uniform(100),
Prob = p11p_config:testing_drop_prob(),
if
Rand =< Prob ->
lager:debug("~p: faking unresponsive token (~p) by not sending",
[self(), Port]);
true ->
lager:debug("~p: sending ~B octets to token", [self(), size(Buf)]),
true = port_command(Port, Buf)
end,
{ok, size(Buf)}.
response_in(S = #state{replyto = Pid, timer = Timer, recv_count = Recv},
MsgIn, DataIn) ->
case p11p_rpc:parse(MsgIn, list_to_binary(DataIn)) of
{needmore, Msg} ->
S#state{response = Msg};
{done, Msg} ->
cancel_timer(Timer),
lager:debug("~p: <- ~s", [self(), p11p_rpc:dump(Msg)]),
{ok, _BytesSent} = p11p_server:reply(Pid, Msg),
%% Saving potential data not consumed by parse/2 in new message.
S#state{response = p11p_rpc:new(Msg#p11rpc_msg.buffer),
p11state = runstate(S#state.p11state, p11p_rpc:req_id(Msg)),
recv_count = Recv + 1}
end.
start_timer(Timeout, Port) ->
%%lager:debug("~p: starting timer", [self()]),
erlang:start_timer(Timeout, self(), Port).
cancel_timer(Timer) ->
%%lager:debug("~p: canceling timer", [self()]),
erlang:cancel_timer(Timer, [{async, true}, {info, false}]).
-spec runstate(token_state(), non_neg_integer()) -> token_state().
runstate(started, ReqId) ->
case ReqId of
?P11_RPC_CALL_C_Initialize ->
initialized;
_ ->
started
end;
runstate(initialized, ReqId) ->
case ReqId of
?P11_RPC_CALL_C_OpenSession ->
session;
?P11_RPC_CALL_C_Finalize ->
finalized;
_ ->
initialized
end;
runstate(session, ReqId) ->
case ReqId of
?P11_RPC_CALL_C_Login ->
loggedin;
?P11_RPC_CALL_C_CloseSession ->
initialized;
?P11_RPC_CALL_C_Finalize ->
finalized;
_ ->
session
end;
runstate(loggedin, ReqId) ->
case ReqId of
?P11_RPC_CALL_C_Logout ->
session;
?P11_RPC_CALL_C_CloseSession ->
initialized;
?P11_RPC_CALL_C_Finalize ->
finalized;
_ ->
loggedin
end.
|
