%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2007-2012. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
%%----------------------------------------------------------------------
%% Purpose: Handles ssl sessions
%%----------------------------------------------------------------------
-module(ssl_session).
-include("ssl_handshake.hrl").
-include("ssl_internal.hrl").
%% Internal application API
-export([is_new/2, client_id/4, server_id/6, valid_session/2]).
-define('24H_in_sec', 8640).
-type seconds() :: integer().
%%--------------------------------------------------------------------
-spec is_new(session_id(), 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({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(ClientInfo, Cache, CacheCb, OwnCert) ->
case select_session(ClientInfo, Cache, CacheCb, OwnCert) of
no_session ->
<<>>;
SessionId ->
SessionId
end.
-spec valid_session(#session{}, seconds()) -> boolean().
%%
%% Description: Check that the session has not expired
%%--------------------------------------------------------------------
valid_session(#session{time_stamp = TimeStamp}, LifeTime) ->
Now = calendar:datetime_to_gregorian_seconds({date(), time()}),
Now - TimeStamp < 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=false}}, _Cache, _CacheCb, _OwnCert) ->
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([_Id, 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;
[[Id, _]|_] -> 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.
