%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2007-2018. 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: Help funtions for handling the TLS (specific parts of)
%%% SSL/TLS/DTLS handshake protocol
%%----------------------------------------------------------------------
-module(tls_handshake).
-include("tls_handshake.hrl").
-include("tls_handshake_1_3.hrl").
-include("tls_record.hrl").
-include("ssl_alert.hrl").
-include("ssl_internal.hrl").
-include("ssl_cipher.hrl").
-include("ssl_api.hrl").
-include_lib("public_key/include/public_key.hrl").
-include_lib("kernel/include/logger.hrl").
%% Handshake handling
-export([client_hello/9, hello/4]).
%% Handshake encoding
-export([encode_handshake/2]).
%% Handshake decodeing
-export([get_tls_handshake/4, decode_handshake/3]).
-type tls_handshake() :: #client_hello{} | ssl_handshake:ssl_handshake().
%%====================================================================
%% Handshake handling
%%====================================================================
%%--------------------------------------------------------------------
-spec client_hello(ssl:host(), inet:port_number(), ssl_record:connection_states(),
#ssl_options{}, integer(), atom(), boolean(), der_cert(),
#key_share_client_hello{} | undefined) ->
#client_hello{}.
%%
%% Description: Creates a client hello message.
%%--------------------------------------------------------------------
client_hello(Host, Port, ConnectionStates,
#ssl_options{versions = Versions,
ciphers = UserSuites,
fallback = Fallback
} = SslOpts,
Cache, CacheCb, Renegotiation, OwnCert, KeyShare) ->
Version = tls_record:highest_protocol_version(Versions),
%% In TLS 1.3, the client indicates its version preferences in the
%% "supported_versions" extension (Section 4.2.1) and the
%% legacy_version field MUST be set to 0x0303, which is the version
%% number for TLS 1.2.
LegacyVersion =
case tls_record:is_higher(Version, {3,2}) of
true ->
{3,3};
false ->
Version
end,
#{security_parameters := SecParams} =
ssl_record:pending_connection_state(ConnectionStates, read),
AvailableCipherSuites = ssl_handshake:available_suites(UserSuites, Version),
Extensions = ssl_handshake:client_hello_extensions(Version,
AvailableCipherSuites,
SslOpts, ConnectionStates,
Renegotiation,
KeyShare),
CipherSuites = ssl_handshake:cipher_suites(AvailableCipherSuites, Renegotiation, Fallback),
Id = ssl_session:client_id({Host, Port, SslOpts}, Cache, CacheCb, OwnCert),
#client_hello{session_id = Id,
client_version = LegacyVersion,
cipher_suites = CipherSuites,
compression_methods = ssl_record:compressions(),
random = SecParams#security_parameters.client_random,
extensions = Extensions
}.
%%--------------------------------------------------------------------
-spec hello(#server_hello{} | #client_hello{}, #ssl_options{},
ssl_record:connection_states() | {inet:port_number(), #session{}, db_handle(),
atom(), ssl_record:connection_states(),
binary() | undefined, ssl:key_algo()},
boolean()) ->
{tls_record:tls_version(), ssl:session_id(),
ssl_record:connection_states(), alpn | npn, binary() | undefined}|
{tls_record:tls_version(), {resumed | new, #session{}},
ssl_record:connection_states(), binary() | undefined,
HelloExt::map(), {ssl:hash(), ssl:sign_algo()} |
undefined} | #alert{}.
%%
%% Description: Handles a received hello message
%%--------------------------------------------------------------------
%% TLS 1.3 - Section 4.1.3
%% TLS 1.3 clients receiving a ServerHello indicating TLS 1.2 or below
%% MUST check that the last eight bytes are not equal to either of these
%% values.
hello(#server_hello{server_version = {Major, Minor},
random = <<_:24/binary,Down:8/binary>>},
#ssl_options{versions = [{M,N}|_]}, _, _)
when (M > 3 orelse M =:= 3 andalso N >= 4) andalso %% TLS 1.3 client
(Major =:= 3 andalso Minor =:= 3 andalso %% Negotiating TLS 1.2
Down =:= ?RANDOM_OVERRIDE_TLS12) orelse
(M > 3 orelse M =:= 3 andalso N >= 4) andalso %% TLS 1.3 client
(Major =:= 3 andalso Minor < 3 andalso %% Negotiating TLS 1.1 or prior
Down =:= ?RANDOM_OVERRIDE_TLS11) ->
?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER);
%% TLS 1.2 clients SHOULD also check that the last eight bytes are not
%% equal to the second value if the ServerHello indicates TLS 1.1 or below.
hello(#server_hello{server_version = {Major, Minor},
random = <<_:24/binary,Down:8/binary>>},
#ssl_options{versions = [{M,N}|_]}, _, _)
when (M =:= 3 andalso N =:= 3) andalso %% TLS 1.2 client
(Major =:= 3 andalso Minor < 3 andalso %% Negotiating TLS 1.1 or prior
Down =:= ?RANDOM_OVERRIDE_TLS11) ->
?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER);
%% TLS 1.3 - 4.2.1. Supported Versions
%% If the "supported_versions" extension in the ServerHello contains a
%% version not offered by the client or contains a version prior to TLS
%% 1.3, the client MUST abort the handshake with an "illegal_parameter"
%% alert.
%%--------------------------------------------------------------------
%% TLS 1.2 Client
%%
%% - If "supported_version" is present (ServerHello):
%% - Abort handshake with an "illegal_parameter" alert
hello(#server_hello{server_version = Version,
extensions = #{server_hello_selected_version :=
#server_hello_selected_version{selected_version = Version}}
},
#ssl_options{versions = SupportedVersions},
_ConnectionStates0, _Renegotiation) ->
case tls_record:is_higher({3,4}, Version) of
true ->
?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER);
false ->
case tls_record:is_acceptable_version(Version, SupportedVersions) of
true ->
%% Implement TLS 1.3 statem ???
?ALERT_REC(?FATAL, ?PROTOCOL_VERSION);
false ->
?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)
end
end;
hello(#server_hello{server_version = Version, random = Random,
cipher_suite = CipherSuite,
compression_method = Compression,
session_id = SessionId, extensions = HelloExt},
#ssl_options{versions = SupportedVersions} = SslOpt,
ConnectionStates0, Renegotiation) ->
case tls_record:is_acceptable_version(Version, SupportedVersions) of
true ->
handle_server_hello_extensions(Version, SessionId, Random, CipherSuite,
Compression, HelloExt, SslOpt,
ConnectionStates0, Renegotiation);
false ->
?ALERT_REC(?FATAL, ?PROTOCOL_VERSION)
end;
%% TLS 1.2 Server
%% - If "supported_versions" is present (ClientHello):
%% - Select version from "supported_versions" (ignore ClientHello.legacy_version)
%% - If server only supports versions greater than "supported_versions":
%% - Abort handshake with a "protocol_version" alert (*)
%% - If "supported_versions" is absent (ClientHello):
%% - Negotiate the minimum of ClientHello.legacy_version and TLS 1.2 (**)
%% - If server only supports versions greater than ClientHello.legacy_version:
%% - Abort handshake with a "protocol_version" alert
%%
%% (*) Sends alert even if there is a gap in supported versions
%% e.g. Server 1.0,1.2 Client 1.1,1.3
%% (**) Current implementation can negotiate a version not supported by the client
%% e.g. Server 1.0,1.2 Client 1.1 -> ServerHello 1.0
hello(#client_hello{client_version = _ClientVersion,
cipher_suites = CipherSuites,
extensions = #{client_hello_versions :=
#client_hello_versions{versions = ClientVersions}
}} = Hello,
#ssl_options{versions = Versions} = SslOpts,
Info, Renegotiation) ->
try
Version = ssl_handshake:select_supported_version(ClientVersions, Versions),
do_hello(Version, Versions, CipherSuites, Hello, SslOpts, Info, Renegotiation)
catch
_:_ ->
?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, malformed_handshake_data)
end;
hello(#client_hello{client_version = ClientVersion,
cipher_suites = CipherSuites} = Hello,
#ssl_options{versions = Versions} = SslOpts,
Info, Renegotiation) ->
try
Version = ssl_handshake:select_version(tls_record, ClientVersion, Versions),
do_hello(Version, Versions, CipherSuites, Hello, SslOpts, Info, Renegotiation)
catch
error:{case_clause,{asn1, Asn1Reason}} ->
%% ASN-1 decode of certificate somehow failed
?ALERT_REC(?FATAL, ?INTERNAL_ERROR, {failed_to_decode_own_certificate, Asn1Reason});
_:_ ->
?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, malformed_handshake_data)
end.
%%--------------------------------------------------------------------
%%% Handshake encodeing
%%--------------------------------------------------------------------
%%--------------------------------------------------------------------
-spec encode_handshake(tls_handshake() | tls_handshake_1_3:tls_handshake_1_3(),
tls_record:tls_version()) -> iolist().
%%
%% Description: Encode a handshake packet
%%--------------------------------------------------------------------
encode_handshake(Package, Version) ->
{MsgType, Bin} = enc_handshake(Package, Version),
Len = byte_size(Bin),
[MsgType, ?uint24(Len), Bin].
%%--------------------------------------------------------------------
%%% Handshake decodeing
%%--------------------------------------------------------------------
%%--------------------------------------------------------------------
-spec get_tls_handshake(tls_record:tls_version(), binary(), binary() | iolist(),
#ssl_options{}) ->
{[tls_handshake()], binary()}.
%%
%% Description: Given buffered and new data from ssl_record, collects
%% and returns it as a list of handshake messages, also returns leftover
%% data.
%%--------------------------------------------------------------------
get_tls_handshake(Version, Data, <<>>, Options) ->
get_tls_handshake_aux(Version, Data, Options, []);
get_tls_handshake(Version, Data, Buffer, Options) ->
get_tls_handshake_aux(Version, list_to_binary([Buffer, Data]), Options, []).
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
handle_client_hello(Version,
#client_hello{session_id = SugesstedId,
cipher_suites = CipherSuites,
compression_methods = Compressions,
random = Random,
extensions = HelloExt},
#ssl_options{versions = Versions,
signature_algs = SupportedHashSigns,
eccs = SupportedECCs,
honor_ecc_order = ECCOrder} = SslOpts,
{Port, Session0, Cache, CacheCb, ConnectionStates0, Cert, _},
Renegotiation) ->
case tls_record:is_acceptable_version(Version, Versions) of
true ->
Curves = maps:get(elliptic_curves, HelloExt, undefined),
ClientHashSigns = maps:get(signature_algs, HelloExt, undefined),
ClientSignatureSchemes = maps:get(signature_algs_cert, HelloExt, undefined),
AvailableHashSigns = ssl_handshake:available_signature_algs(
ClientHashSigns, SupportedHashSigns, Cert, Version),
ECCCurve = ssl_handshake:select_curve(Curves, SupportedECCs, ECCOrder),
{Type, #session{cipher_suite = CipherSuite} = Session1}
= ssl_handshake:select_session(SugesstedId, CipherSuites,
AvailableHashSigns, Compressions,
Port, Session0#session{ecc = ECCCurve},
Version, SslOpts, Cache, CacheCb, Cert),
case CipherSuite of
no_suite ->
?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_ciphers);
_ ->
#{key_exchange := KeyExAlg} = ssl_cipher_format:suite_definition(CipherSuite),
case ssl_handshake:select_hashsign({ClientHashSigns, ClientSignatureSchemes},
Cert, KeyExAlg,
SupportedHashSigns,
Version) of
#alert{} = Alert ->
Alert;
HashSign ->
handle_client_hello_extensions(Version, Type, Random,
CipherSuites, HelloExt,
SslOpts, Session1,
ConnectionStates0,
Renegotiation, HashSign)
end
end;
false ->
?ALERT_REC(?FATAL, ?PROTOCOL_VERSION)
end.
handle_client_hello_extensions(Version, Type, Random, CipherSuites,
HelloExt, SslOpts, Session0, ConnectionStates0,
Renegotiation, HashSign) ->
try ssl_handshake:handle_client_hello_extensions(tls_record, Random, CipherSuites,
HelloExt, Version, SslOpts,
Session0, ConnectionStates0,
Renegotiation) of
{Session, ConnectionStates, Protocol, ServerHelloExt} ->
{Version, {Type, Session}, ConnectionStates, Protocol,
ServerHelloExt, HashSign}
catch throw:Alert ->
Alert
end.
handle_server_hello_extensions(Version, SessionId, Random, CipherSuite,
Compression, HelloExt, SslOpt, ConnectionStates0, Renegotiation) ->
try ssl_handshake:handle_server_hello_extensions(tls_record, Random, CipherSuite,
Compression, HelloExt, Version,
SslOpt, ConnectionStates0,
Renegotiation) of
{ConnectionStates, ProtoExt, Protocol} ->
{Version, SessionId, ConnectionStates, ProtoExt, Protocol}
catch throw:Alert ->
Alert
end.
do_hello(undefined, _Versions, _CipherSuites, _Hello, _SslOpts, _Info, _Renegotiation) ->
?ALERT_REC(?FATAL, ?PROTOCOL_VERSION);
do_hello(Version, Versions, CipherSuites, Hello, SslOpts, Info, Renegotiation) ->
case ssl_cipher:is_fallback(CipherSuites) of
true ->
Highest = tls_record:highest_protocol_version(Versions),
case tls_record:is_higher(Highest, Version) of
true ->
?ALERT_REC(?FATAL, ?INAPPROPRIATE_FALLBACK);
false ->
handle_client_hello(Version, Hello, SslOpts, Info, Renegotiation)
end;
false ->
handle_client_hello(Version, Hello, SslOpts, Info, Renegotiation)
end.
%%--------------------------------------------------------------------
enc_handshake(#hello_request{}, {3, N}) when N < 4 ->
{?HELLO_REQUEST, <<>>};
enc_handshake(#client_hello{client_version = {Major, Minor},
random = Random,
session_id = SessionID,
cipher_suites = CipherSuites,
compression_methods = CompMethods,
extensions = HelloExtensions}, _Version) ->
SIDLength = byte_size(SessionID),
BinCompMethods = list_to_binary(CompMethods),
CmLength = byte_size(BinCompMethods),
BinCipherSuites = list_to_binary(CipherSuites),
CsLength = byte_size(BinCipherSuites),
ExtensionsBin = ssl_handshake:encode_hello_extensions(HelloExtensions),
{?CLIENT_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
?BYTE(SIDLength), SessionID/binary,
?UINT16(CsLength), BinCipherSuites/binary,
?BYTE(CmLength), BinCompMethods/binary, ExtensionsBin/binary>>};
enc_handshake(HandshakeMsg, {3, 4}) ->
tls_handshake_1_3:encode_handshake(HandshakeMsg);
enc_handshake(HandshakeMsg, Version) ->
ssl_handshake:encode_handshake(HandshakeMsg, Version).
%%--------------------------------------------------------------------
get_tls_handshake_aux(Version, <<?BYTE(Type), ?UINT24(Length),
Body:Length/binary,Rest/binary>>,
Opts, Acc) ->
Raw = <<?BYTE(Type), ?UINT24(Length), Body/binary>>,
try decode_handshake(Version, Type, Body) of
Handshake ->
ssl_logger:debug(Opts#ssl_options.log_level, inbound, 'handshake', Handshake),
get_tls_handshake_aux(Version, Rest, Opts, [{Handshake,Raw} | Acc])
catch
_:_ ->
throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, handshake_decode_error))
end;
get_tls_handshake_aux(_Version, Data, _, Acc) ->
{lists:reverse(Acc), Data}.
decode_handshake({3, N}, ?HELLO_REQUEST, <<>>) when N < 4 ->
#hello_request{};
decode_handshake(Version, ?CLIENT_HELLO,
<<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
?BYTE(SID_length), Session_ID:SID_length/binary,
?UINT16(Cs_length), CipherSuites:Cs_length/binary,
?BYTE(Cm_length), Comp_methods:Cm_length/binary,
Extensions/binary>>) ->
Exts = ssl_handshake:decode_vector(Extensions),
DecodedExtensions = ssl_handshake:decode_hello_extensions(Exts, Version, {Major, Minor},
client_hello),
#client_hello{
client_version = {Major,Minor},
random = Random,
session_id = Session_ID,
cipher_suites = ssl_handshake:decode_suites('2_bytes', CipherSuites),
compression_methods = erlang:binary_to_list(Comp_methods),
extensions = DecodedExtensions
};
decode_handshake({3, 4}, Tag, Msg) ->
tls_handshake_1_3:decode_handshake(Tag, Msg);
decode_handshake(Version, Tag, Msg) ->
ssl_handshake:decode_handshake(Version, Tag, Msg).
