%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2007-2016. All Rights Reserved.
%%
%% 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.
%%
%% %CopyrightEnd%
%%
%%
%%----------------------------------------------------------------------
%% Purpose: Handles ssl sessions
%%----------------------------------------------------------------------
-module(ssl_session).
-include("ssl_handshake.hrl").
-include("ssl_internal.hrl").
-include("ssl_api.hrl").
%% Internal application API
-export([is_new/2, client_id/4, server_id/6, valid_session/2]).
-type seconds() :: integer().
%%--------------------------------------------------------------------
-spec is_new(ssl:session_id(), ssl:session_id()) -> boolean().
%%
%% Description: Checks if the session id decided by the server is a
%% new or resumed sesion id.
%%--------------------------------------------------------------------
is_new(<<>>, _) ->
true;
is_new(SessionId, SessionId) ->
false;
is_new(_ClientSuggestion, _ServerDecision) ->
true.
%%--------------------------------------------------------------------
-spec client_id({ssl:host(), inet:port_number(), #ssl_options{}}, db_handle(), atom(),
undefined | binary()) -> binary().
%%
%% Description: Should be called by the client side to get an id
%% for the client hello message.
%%--------------------------------------------------------------------
client_id({Host, Port, #ssl_options{reuse_session = SessionId}}, Cache, CacheCb, _) when is_binary(SessionId)->
case CacheCb:lookup(Cache, {{Host, Port}, SessionId}) of
undefined ->
<<>>;
#session{} ->
SessionId
end;
client_id(ClientInfo, Cache, CacheCb, OwnCert) ->
case select_session(ClientInfo, Cache, CacheCb, OwnCert) of
no_session ->
<<>>;
SessionId ->
SessionId
end.
-spec valid_session(#session{}, seconds() | {invalidate_before, integer()}) -> boolean().
%%
%% Description: Check that the session has not expired
%%--------------------------------------------------------------------
valid_session(#session{time_stamp = TimeStamp}, {invalidate_before, Before}) ->
TimeStamp > Before;
valid_session(#session{time_stamp = TimeStamp}, LifeTime) ->
Now = erlang:monotonic_time(),
Lived = erlang:convert_time_unit(Now-TimeStamp, native, seconds),
Lived < LifeTime.
server_id(Port, <<>>, _SslOpts, _Cert, _, _) ->
{ssl_manager:new_session_id(Port), undefined};
server_id(Port, SuggestedId, Options, Cert, Cache, CacheCb) ->
LifeTime = case application:get_env(ssl, session_lifetime) of
{ok, Time} when is_integer(Time) -> Time;
_ -> ?'24H_in_sec'
end,
case is_resumable(SuggestedId, Port, Options,
Cache, CacheCb, LifeTime, Cert)
of
{true, Resumed} ->
{SuggestedId, Resumed};
{false, undefined} ->
{ssl_manager:new_session_id(Port), undefined}
end.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
select_session({_, _, #ssl_options{reuse_sessions = Reuse}}, _Cache, _CacheCb, _OwnCert) when Reuse =/= true ->
%% If reuse_sessions == true | save a new session should be created
no_session;
select_session({HostIP, Port, SslOpts}, Cache, CacheCb, OwnCert) ->
Sessions = CacheCb:select_session(Cache, {HostIP, Port}),
select_session(Sessions, SslOpts, OwnCert).
select_session([], _, _) ->
no_session;
select_session(Sessions, #ssl_options{ciphers = Ciphers}, OwnCert) ->
IsNotResumable =
fun(Session) ->
not (resumable(Session#session.is_resumable) andalso
lists:member(Session#session.cipher_suite, Ciphers)
andalso (OwnCert == Session#session.own_certificate))
end,
case lists:dropwhile(IsNotResumable, Sessions) of
[] -> no_session;
[Session | _] -> Session#session.session_id
end.
is_resumable(_, _, #ssl_options{reuse_sessions = false}, _, _, _, _) ->
{false, undefined};
is_resumable(SuggestedSessionId, Port, #ssl_options{reuse_session = ReuseFun} = Options, Cache,
CacheCb, SecondLifeTime, OwnCert) ->
case CacheCb:lookup(Cache, {Port, SuggestedSessionId}) of
#session{cipher_suite = CipherSuite,
own_certificate = SessionOwnCert,
compression_method = Compression,
is_resumable = IsResumable,
peer_certificate = PeerCert} = Session ->
case resumable(IsResumable)
andalso (OwnCert == SessionOwnCert)
andalso valid_session(Session, SecondLifeTime)
andalso reusable_options(Options, Session)
andalso ReuseFun(SuggestedSessionId, PeerCert,
Compression, CipherSuite)
of
true -> {true, Session};
false -> {false, undefined}
end;
undefined ->
{false, undefined}
end.
resumable(new) ->
false;
resumable(IsResumable) ->
IsResumable.
reusable_options(#ssl_options{fail_if_no_peer_cert = true,
verify = verify_peer}, Session) ->
(Session#session.peer_certificate =/= undefined);
reusable_options(_,_) ->
true.
