%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2013-2016. 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: Handle TLS/SSL/DTLS record protocol. Note epoch is only
%% used by DTLS but handled here so we can avoid code duplication.
%%----------------------------------------------------------------------
-module(ssl_record).
-include("ssl_record.hrl").
-include("ssl_internal.hrl").
-include("ssl_cipher.hrl").
-include("ssl_alert.hrl").
%% Connection state handling
-export([initial_security_params/1, current_connection_state/2, pending_connection_state/2,
activate_pending_connection_state/2,
set_security_params/3,
set_mac_secret/4,
set_master_secret/2,
set_pending_cipher_state/4,
set_renegotiation_flag/2,
set_client_verify_data/3,
set_server_verify_data/3,
empty_connection_state/2, initial_connection_state/2, record_protocol_role/1]).
%% Encoding records
-export([encode_handshake/3, encode_alert_record/3,
encode_change_cipher_spec/2, encode_data/3]).
%% Compression
-export([compress/3, uncompress/3, compressions/0]).
%% Payload encryption/decryption
-export([cipher/4, decipher/4, is_correct_mac/2,
cipher_aead/4, decipher_aead/4]).
-export_type([ssl_version/0, ssl_atom_version/0, connection_states/0, connection_state/0]).
-type ssl_version() :: {integer(), integer()}.
-type ssl_atom_version() :: tls_record:tls_atom_version().
-type connection_states() :: term(). %% Map
-type connection_state() :: term(). %% Map
%%====================================================================
%% Internal application API
%%====================================================================
%%--------------------------------------------------------------------
-spec current_connection_state(connection_states(), read | write) ->
connection_state().
%%
%% Description: Returns the instance of the connection_state map
%% that is currently defined as the current conection state.
%%--------------------------------------------------------------------
current_connection_state(ConnectionStates, read) ->
maps:get(current_read, ConnectionStates);
current_connection_state(ConnectionStates, write) ->
maps:get(current_write, ConnectionStates).
%%--------------------------------------------------------------------
-spec pending_connection_state(connection_states(), read | write) ->
connection_state().
%%
%% Description: Returns the instance of the connection_state map
%% that is pendingly defined as the pending conection state.
%%--------------------------------------------------------------------
pending_connection_state(ConnectionStates, read) ->
maps:get(pending_read, ConnectionStates);
pending_connection_state(ConnectionStates, write) ->
maps:get(pending_write, ConnectionStates).
%%--------------------------------------------------------------------
-spec activate_pending_connection_state(connection_states(), read | write) ->
connection_states().
%%
%% Description: Creates a new instance of the connection_states record
%% where the pending state of <Type> has been activated.
%%--------------------------------------------------------------------
activate_pending_connection_state(#{current_read := Current,
pending_read := Pending} = States,
read) ->
#{secure_renegotiation := SecureRenegotation} = Current,
#{beast_mitigation := BeastMitigation,
security_parameters := SecParams} = Pending,
NewCurrent = Pending#{sequence_number => 0},
ConnectionEnd = SecParams#security_parameters.connection_end,
EmptyPending = empty_connection_state(ConnectionEnd, BeastMitigation),
NewPending = EmptyPending#{secure_renegotiation => SecureRenegotation},
States#{current_read => NewCurrent,
pending_read => NewPending
};
activate_pending_connection_state(#{current_write := Current,
pending_write := Pending} = States,
write) ->
NewCurrent = Pending#{sequence_number => 0},
#{secure_renegotiation := SecureRenegotation} = Current,
#{beast_mitigation := BeastMitigation,
security_parameters := SecParams} = Pending,
ConnectionEnd = SecParams#security_parameters.connection_end,
EmptyPending = empty_connection_state(ConnectionEnd, BeastMitigation),
NewPending = EmptyPending#{secure_renegotiation => SecureRenegotation},
States#{current_write => NewCurrent,
pending_write => NewPending
}.
%%--------------------------------------------------------------------
-spec set_security_params(#security_parameters{}, #security_parameters{},
connection_states()) -> connection_states().
%%
%% Description: Creates a new instance of the connection_states record
%% where the pending states gets its security parameters updated.
%%--------------------------------------------------------------------
set_security_params(ReadParams, WriteParams,
#{pending_read := Read,
pending_write := Write} = States) ->
States#{pending_read => Read#{security_parameters => ReadParams},
pending_write => Write#{security_parameters => WriteParams}
}.
%%--------------------------------------------------------------------
-spec set_mac_secret(binary(), binary(), client | server,
connection_states()) -> connection_states().
%%
%% Description: update the mac_secret field in pending connection states
%%--------------------------------------------------------------------
set_mac_secret(ClientWriteMacSecret, ServerWriteMacSecret, client, States) ->
set_mac_secret(ServerWriteMacSecret, ClientWriteMacSecret, States);
set_mac_secret(ClientWriteMacSecret, ServerWriteMacSecret, server, States) ->
set_mac_secret(ClientWriteMacSecret, ServerWriteMacSecret, States).
set_mac_secret(ReadMacSecret, WriteMacSecret,
States = #{pending_read := Read,
pending_write := Write}) ->
States#{pending_read => Read#{mac_secret => ReadMacSecret},
pending_write => Write#{mac_secret => WriteMacSecret}
}.
%%--------------------------------------------------------------------
-spec set_master_secret(binary(), connection_states()) -> connection_states().
%%
%% Description: Set master_secret in pending connection states
%%--------------------------------------------------------------------
set_master_secret(MasterSecret,
States = #{pending_read := Read = #{security_parameters := ReadSecPar},
pending_write := Write = #{security_parameters := WriteSecPar}}) ->
Read1 = Read#{security_parameters => ReadSecPar#security_parameters{
master_secret = MasterSecret}},
Write1 = Write#{security_parameters => WriteSecPar#security_parameters{
master_secret = MasterSecret}},
States#{pending_read => Read1, pending_write => Write1}.
%%--------------------------------------------------------------------
-spec set_renegotiation_flag(boolean(), connection_states()) -> connection_states().
%%
%% Description: Set secure_renegotiation in pending connection states
%%--------------------------------------------------------------------
set_renegotiation_flag(Flag, #{current_read := CurrentRead0,
current_write := CurrentWrite0,
pending_read := PendingRead0,
pending_write := PendingWrite0}
= ConnectionStates) ->
CurrentRead = CurrentRead0#{secure_renegotiation => Flag},
CurrentWrite = CurrentWrite0#{secure_renegotiation => Flag},
PendingRead = PendingRead0#{secure_renegotiation => Flag},
PendingWrite = PendingWrite0#{secure_renegotiation => Flag},
ConnectionStates#{current_read => CurrentRead,
current_write => CurrentWrite,
pending_read => PendingRead,
pending_write => PendingWrite}.
%%--------------------------------------------------------------------
-spec set_client_verify_data(current_read | current_write | current_both,
binary(), connection_states())->
connection_states().
%%
%% Description: Set verify data in connection states.
%%--------------------------------------------------------------------
set_client_verify_data(current_read, Data,
#{current_read := CurrentRead0,
pending_write := PendingWrite0}
= ConnectionStates) ->
CurrentRead = CurrentRead0#{client_verify_data => Data},
PendingWrite = PendingWrite0#{client_verify_data => Data},
ConnectionStates#{current_read => CurrentRead,
pending_write => PendingWrite};
set_client_verify_data(current_write, Data,
#{pending_read := PendingRead0,
current_write := CurrentWrite0}
= ConnectionStates) ->
PendingRead = PendingRead0#{client_verify_data => Data},
CurrentWrite = CurrentWrite0#{client_verify_data => Data},
ConnectionStates#{pending_read => PendingRead,
current_write => CurrentWrite};
set_client_verify_data(current_both, Data,
#{current_read := CurrentRead0,
current_write := CurrentWrite0}
= ConnectionStates) ->
CurrentRead = CurrentRead0#{client_verify_data => Data},
CurrentWrite = CurrentWrite0#{client_verify_data => Data},
ConnectionStates#{current_read => CurrentRead,
current_write => CurrentWrite}.
%%--------------------------------------------------------------------
-spec set_server_verify_data(current_read | current_write | current_both,
binary(), connection_states())->
connection_states().
%%
%% Description: Set verify data in pending connection states.
%%--------------------------------------------------------------------
set_server_verify_data(current_write, Data,
#{pending_read := PendingRead0,
current_write := CurrentWrite0}
= ConnectionStates) ->
PendingRead = PendingRead0#{server_verify_data => Data},
CurrentWrite = CurrentWrite0#{server_verify_data => Data},
ConnectionStates#{pending_read => PendingRead,
current_write => CurrentWrite};
set_server_verify_data(current_read, Data,
#{current_read := CurrentRead0,
pending_write := PendingWrite0}
= ConnectionStates) ->
CurrentRead = CurrentRead0#{server_verify_data => Data},
PendingWrite = PendingWrite0#{server_verify_data => Data},
ConnectionStates#{current_read => CurrentRead,
pending_write => PendingWrite};
set_server_verify_data(current_both, Data,
#{current_read := CurrentRead0,
current_write := CurrentWrite0}
= ConnectionStates) ->
CurrentRead = CurrentRead0#{server_verify_data => Data},
CurrentWrite = CurrentWrite0#{server_verify_data => Data},
ConnectionStates#{current_read => CurrentRead,
current_write => CurrentWrite}.
%%--------------------------------------------------------------------
-spec set_pending_cipher_state(connection_states(), #cipher_state{},
#cipher_state{}, client | server) ->
connection_states().
%%
%% Description: Set the cipher state in the specified pending connection state.
%%--------------------------------------------------------------------
set_pending_cipher_state(#{pending_read := Read,
pending_write := Write} = States,
ClientState, ServerState, server) ->
States#{
pending_read => Read#{cipher_state => ClientState},
pending_write => Write#{cipher_state => ServerState}};
set_pending_cipher_state(#{pending_read := Read,
pending_write := Write} = States,
ClientState, ServerState, client) ->
States#{
pending_read => Read#{cipher_state => ServerState},
pending_write => Write#{cipher_state => ClientState}}.
%%--------------------------------------------------------------------
-spec encode_handshake(iolist(), ssl_version(), connection_states()) ->
{iolist(), connection_states()}.
%%
%% Description: Encodes a handshake message to send on the ssl-socket.
%%--------------------------------------------------------------------
encode_handshake(Frag, Version,
#{current_write :=
#{beast_mitigation := BeastMitigation,
security_parameters :=
#security_parameters{bulk_cipher_algorithm = BCA}}} =
ConnectionStates)
when is_list(Frag) ->
case iolist_size(Frag) of
N when N > ?MAX_PLAIN_TEXT_LENGTH ->
Data = split_bin(iolist_to_binary(Frag), ?MAX_PLAIN_TEXT_LENGTH, Version, BCA, BeastMitigation),
encode_iolist(?HANDSHAKE, Data, Version, ConnectionStates);
_ ->
encode_plain_text(?HANDSHAKE, Version, Frag, ConnectionStates)
end;
%% TODO: this is a workarround for DTLS
%%
%% DTLS need to select the connection write state based on Epoch it wants to
%% send this fragment in. That Epoch does not nessarily has to be the same
%% as the current_write epoch.
%% The right solution might be to pass the WriteState instead of the ConnectionStates,
%% however, this will require substantion API changes.
encode_handshake(Frag, Version, ConnectionStates) ->
encode_plain_text(?HANDSHAKE, Version, Frag, ConnectionStates).
%%--------------------------------------------------------------------
-spec encode_alert_record(#alert{}, ssl_version(), connection_states()) ->
{iolist(), connection_states()}.
%%
%% Description: Encodes an alert message to send on the ssl-socket.
%%--------------------------------------------------------------------
encode_alert_record(#alert{level = Level, description = Description},
Version, ConnectionStates) ->
encode_plain_text(?ALERT, Version, <<?BYTE(Level), ?BYTE(Description)>>,
ConnectionStates).
%%--------------------------------------------------------------------
-spec encode_change_cipher_spec(ssl_version(), connection_states()) ->
{iolist(), connection_states()}.
%%
%% Description: Encodes a change_cipher_spec-message to send on the ssl socket.
%%--------------------------------------------------------------------
encode_change_cipher_spec(Version, ConnectionStates) ->
encode_plain_text(?CHANGE_CIPHER_SPEC, Version, <<1:8>>, ConnectionStates).
%%--------------------------------------------------------------------
-spec encode_data(binary(), ssl_version(), connection_states()) ->
{iolist(), connection_states()}.
%%
%% Description: Encodes data to send on the ssl-socket.
%%--------------------------------------------------------------------
encode_data(Frag, Version,
#{current_write := #{beast_mitigation := BeastMitigation,
security_parameters :=
#security_parameters{bulk_cipher_algorithm = BCA}}} =
ConnectionStates) ->
Data = split_bin(Frag, ?MAX_PLAIN_TEXT_LENGTH, Version, BCA, BeastMitigation),
encode_iolist(?APPLICATION_DATA, Data, Version, ConnectionStates).
uncompress(?NULL, Data, CS) ->
{Data, CS}.
compress(?NULL, Data, CS) ->
{Data, CS}.
%%--------------------------------------------------------------------
-spec compressions() -> [binary()].
%%
%% Description: return a list of compressions supported (currently none)
%%--------------------------------------------------------------------
compressions() ->
[?byte(?NULL)].
%%--------------------------------------------------------------------
-spec cipher(ssl_version(), iodata(), connection_state(), MacHash::binary()) ->
{CipherFragment::binary(), connection_state()}.
%%
%% Description: Payload encryption
%%--------------------------------------------------------------------
cipher(Version, Fragment,
#{cipher_state := CipherS0,
security_parameters :=
#security_parameters{bulk_cipher_algorithm =
BulkCipherAlgo}
} = WriteState0, MacHash) ->
{CipherFragment, CipherS1} =
ssl_cipher:cipher(BulkCipherAlgo, CipherS0, MacHash, Fragment, Version),
{CipherFragment, WriteState0#{cipher_state => CipherS1}}.
%%--------------------------------------------------------------------
-spec cipher_aead(ssl_version(), iodata(), connection_state(), MacHash::binary()) ->
{CipherFragment::binary(), connection_state()}.
%%
%% Description: Payload encryption
%%--------------------------------------------------------------------
cipher_aead(Version, Fragment,
#{cipher_state := CipherS0,
sequence_number := SeqNo,
security_parameters :=
#security_parameters{bulk_cipher_algorithm =
BulkCipherAlgo}
} = WriteState0, AAD) ->
{CipherFragment, CipherS1} =
ssl_cipher:cipher_aead(BulkCipherAlgo, CipherS0, SeqNo, AAD, Fragment, Version),
{CipherFragment, WriteState0#{cipher_state => CipherS1}}.
%%--------------------------------------------------------------------
-spec decipher(ssl_version(), binary(), connection_state(), boolean()) -> {binary(), binary(), connection_state} | #alert{}.
%%
%% Description: Payload decryption
%%--------------------------------------------------------------------
decipher(Version, CipherFragment,
#{security_parameters :=
#security_parameters{bulk_cipher_algorithm =
BulkCipherAlgo,
hash_size = HashSz},
cipher_state := CipherS0
} = ReadState, PaddingCheck) ->
case ssl_cipher:decipher(BulkCipherAlgo, HashSz, CipherS0, CipherFragment, Version, PaddingCheck) of
{PlainFragment, Mac, CipherS1} ->
CS1 = ReadState#{cipher_state => CipherS1},
{PlainFragment, Mac, CS1};
#alert{} = Alert ->
Alert
end.
%%--------------------------------------------------------------------
-spec decipher_aead(ssl_version(), binary(), connection_state(), binary()) ->
{binary(), binary(), connection_state()} | #alert{}.
%%
%% Description: Payload decryption
%%--------------------------------------------------------------------
decipher_aead(Version, CipherFragment,
#{sequence_number := SeqNo,
security_parameters :=
#security_parameters{bulk_cipher_algorithm =
BulkCipherAlgo},
cipher_state := CipherS0
} = ReadState, AAD) ->
case ssl_cipher:decipher_aead(BulkCipherAlgo, CipherS0, SeqNo, AAD, CipherFragment, Version) of
{PlainFragment, CipherS1} ->
CS1 = ReadState#{cipher_state => CipherS1},
{PlainFragment, CS1};
#alert{} = Alert ->
Alert
end.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
empty_connection_state(ConnectionEnd, BeastMitigation) ->
SecParams = empty_security_params(ConnectionEnd),
#{security_parameters => SecParams,
beast_mitigation => BeastMitigation,
compression_state => undefined,
cipher_state => undefined,
mac_secret => undefined,
secure_renegotiation => undefined,
client_verify_data => undefined,
server_verify_data => undefined
}.
empty_security_params(ConnectionEnd = ?CLIENT) ->
#security_parameters{connection_end = ConnectionEnd,
client_random = random()};
empty_security_params(ConnectionEnd = ?SERVER) ->
#security_parameters{connection_end = ConnectionEnd,
server_random = random()}.
random() ->
Secs_since_1970 = calendar:datetime_to_gregorian_seconds(
calendar:universal_time()) - 62167219200,
Random_28_bytes = ssl_cipher:random_bytes(28),
<<?UINT32(Secs_since_1970), Random_28_bytes/binary>>.
%% dtls_next_epoch(#connection_state{epoch = undefined}) -> %% SSL/TLS
%% undefined;
%% dtls_next_epoch(#connection_state{epoch = Epoch}) -> %% DTLS
%% Epoch + 1.
is_correct_mac(Mac, Mac) ->
true;
is_correct_mac(_M,_H) ->
false.
record_protocol_role(client) ->
?CLIENT;
record_protocol_role(server) ->
?SERVER.
initial_connection_state(ConnectionEnd, BeastMitigation) ->
#{security_parameters =>
initial_security_params(ConnectionEnd),
sequence_number => 0,
beast_mitigation => BeastMitigation,
compression_state => undefined,
cipher_state => undefined,
mac_secret => undefined,
secure_renegotiation => undefined,
client_verify_data => undefined,
server_verify_data => undefined
}.
initial_security_params(ConnectionEnd) ->
SecParams = #security_parameters{connection_end = ConnectionEnd,
compression_algorithm = ?NULL},
ssl_cipher:security_parameters(?TLS_NULL_WITH_NULL_NULL, SecParams).
encode_plain_text(Type, Version, Data, ConnectionStates) ->
RecordCB = protocol_module(Version),
RecordCB:encode_plain_text(Type, Version, Data, ConnectionStates).
encode_iolist(Type, Data, Version, ConnectionStates0) ->
RecordCB = protocol_module(Version),
{ConnectionStates, EncodedMsg} =
lists:foldl(fun(Text, {CS0, Encoded}) ->
{Enc, CS1} =
RecordCB:encode_plain_text(Type, Version, Text, CS0),
{CS1, [Enc | Encoded]}
end, {ConnectionStates0, []}, Data),
{lists:reverse(EncodedMsg), ConnectionStates}.
%% 1/n-1 splitting countermeasure Rizzo/Duong-Beast, RC4 chiphers are
%% not vulnerable to this attack.
split_bin(<<FirstByte:8, Rest/binary>>, ChunkSize, Version, BCA, one_n_minus_one) when
BCA =/= ?RC4 andalso ({3, 1} == Version orelse
{3, 0} == Version) ->
do_split_bin(Rest, ChunkSize, [[FirstByte]]);
%% 0/n splitting countermeasure for clients that are incompatible with 1/n-1
%% splitting.
split_bin(Bin, ChunkSize, Version, BCA, zero_n) when
BCA =/= ?RC4 andalso ({3, 1} == Version orelse
{3, 0} == Version) ->
do_split_bin(Bin, ChunkSize, [[<<>>]]);
split_bin(Bin, ChunkSize, _, _, _) ->
do_split_bin(Bin, ChunkSize, []).
do_split_bin(<<>>, _, Acc) ->
lists:reverse(Acc);
do_split_bin(Bin, ChunkSize, Acc) ->
case Bin of
<<Chunk:ChunkSize/binary, Rest/binary>> ->
do_split_bin(Rest, ChunkSize, [Chunk | Acc]);
_ ->
lists:reverse(Acc, [Bin])
end.
protocol_module({3, _}) ->
tls_record;
protocol_module({254, _}) ->
dtls_record.
