From fb6ac178ac437fcc04f1675df75b0583c1d24ad7 Mon Sep 17 00:00:00 2001 From: Andreas Schultz Date: Wed, 12 Jun 2013 16:26:24 +0200 Subject: ssl: Add DTLS record primitives This code is to 99 % written by Andreas Schultz only some small changes to start integrating with OTPs DTLS solution. --- lib/ssl/src/dtls_record.erl | 322 ++++++++++++++++++++++++++++++++++++++++++++ lib/ssl/src/dtls_record.hrl | 12 ++ lib/ssl/src/ssl_record.hrl | 29 ++-- lib/ssl/src/tls_record.hrl | 6 + 4 files changed, 351 insertions(+), 18 deletions(-) (limited to 'lib/ssl') diff --git a/lib/ssl/src/dtls_record.erl b/lib/ssl/src/dtls_record.erl index 2469a7d26c..98c60f599c 100644 --- a/lib/ssl/src/dtls_record.erl +++ b/lib/ssl/src/dtls_record.erl @@ -16,3 +16,325 @@ %% %% %CopyrightEnd% -module(dtls_record). + +-include("dtls_record.hrl"). +-include("ssl_internal.hrl"). +-include("ssl_alert.hrl"). + +-export([init_connection_state_seq/2, current_connection_state_epoch/2, + set_connection_state_by_epoch/3, connection_state_by_epoch/3]). + +%% Handling of incoming data +-export([get_dtls_records/2]). + +%% Misc. +-export([protocol_version/1, lowest_protocol_version/2, + highest_protocol_version/1, supported_protocol_versions/0, + is_acceptable_version/2]). + +%%-------------------------------------------------------------------- +-spec init_connection_state_seq(tls_version(), #connection_states{}) -> + #connection_state{}. +%% +%% Description: Copy the read sequence number to the write sequence number +%% This is only valid for DTLS in the first client_hello +%%-------------------------------------------------------------------- +init_connection_state_seq({254, _}, + #connection_states{ + current_read = Read = #connection_state{epoch = 0}, + current_write = Write = #connection_state{epoch = 0}} = CS0) -> + CS0#connection_states{current_write = + Write#connection_state{ + sequence_number = Read#connection_state.sequence_number}}; +init_connection_state_seq(_, CS) -> + CS. + +%%-------------------------------------------------------- +-spec current_connection_state_epoch(#connection_states{}, read | write) -> + integer(). +%% +%% Description: Returns the epoch the connection_state record +%% that is currently defined as the current conection state. +%%-------------------------------------------------------------------- +current_connection_state_epoch(#connection_states{current_read = Current}, + read) -> + Current#connection_state.epoch; +current_connection_state_epoch(#connection_states{current_write = Current}, + write) -> + Current#connection_state.epoch. + +%%-------------------------------------------------------------------- + +-spec connection_state_by_epoch(#connection_states{}, integer(), read | write) -> + #connection_state{}. +%% +%% Description: Returns the instance of the connection_state record +%% that is defined by the Epoch. +%%-------------------------------------------------------------------- +connection_state_by_epoch(#connection_states{previous_read = CS}, Epoch, read) + when CS#connection_state.epoch == Epoch -> + CS; +connection_state_by_epoch(#connection_states{current_read = CS}, Epoch, read) + when CS#connection_state.epoch == Epoch -> + CS; +connection_state_by_epoch(#connection_states{pending_read = CS}, Epoch, read) + when CS#connection_state.epoch == Epoch -> + CS; +connection_state_by_epoch(#connection_states{previous_write = CS}, Epoch, write) + when CS#connection_state.epoch == Epoch -> + CS; +connection_state_by_epoch(#connection_states{current_write = CS}, Epoch, write) + when CS#connection_state.epoch == Epoch -> + CS; +connection_state_by_epoch(#connection_states{pending_write = CS}, Epoch, write) + when CS#connection_state.epoch == Epoch -> + CS. + +%%-------------------------------------------------------------------- +-spec set_connection_state_by_epoch(#connection_states{}, + #connection_state{}, read | write) -> ok. +%% +%% Description: Returns the instance of the connection_state record +%% that is defined by the Epoch. +%%-------------------------------------------------------------------- +set_connection_state_by_epoch(ConnectionStates0 = + #connection_states{previous_read = CS}, + NewCS = #connection_state{epoch = Epoch}, read) + when CS#connection_state.epoch == Epoch -> + ConnectionStates0#connection_states{previous_read = NewCS}; + +set_connection_state_by_epoch(ConnectionStates0 = + #connection_states{current_read = CS}, + NewCS = #connection_state{epoch = Epoch}, read) + when CS#connection_state.epoch == Epoch -> + ConnectionStates0#connection_states{current_read = NewCS}; + +set_connection_state_by_epoch(ConnectionStates0 = + #connection_states{pending_read = CS}, + NewCS = #connection_state{epoch = Epoch}, read) + when CS#connection_state.epoch == Epoch -> + ConnectionStates0#connection_states{pending_read = NewCS}; + +set_connection_state_by_epoch(ConnectionStates0 = + #connection_states{previous_write = CS}, + NewCS = #connection_state{epoch = Epoch}, write) + when CS#connection_state.epoch == Epoch -> + ConnectionStates0#connection_states{previous_write = NewCS}; + +set_connection_state_by_epoch(ConnectionStates0 = + #connection_states{current_write = CS}, + NewCS = #connection_state{epoch = Epoch}, write) + when CS#connection_state.epoch == Epoch -> + ConnectionStates0#connection_states{current_write = NewCS}; + +set_connection_state_by_epoch(ConnectionStates0 = + #connection_states{pending_write = CS}, + NewCS = #connection_state{epoch = Epoch}, write) + when CS#connection_state.epoch == Epoch -> + ConnectionStates0#connection_states{pending_write = NewCS}. + + +%%-------------------------------------------------------------------- +-spec protocol_version(tls_atom_version() | tls_version()) -> + tls_version() | tls_atom_version(). +%% +%% Description: Creates a protocol version record from a version atom +%% or vice versa. +%%-------------------------------------------------------------------- +protocol_version('dtlsv1.2') -> + {254, 253}; +protocol_version(dtlsv1) -> + {254, 255}; +protocol_version({254, 253}) -> + 'dtlsv1.2'; +protocol_version({254, 255}) -> + dtlsv1. +%%-------------------------------------------------------------------- +-spec lowest_protocol_version(tls_version(), tls_version()) -> tls_version(). +%% +%% Description: Lowes protocol version of two given versions +%%-------------------------------------------------------------------- +lowest_protocol_version(Version = {M, N}, {M, O}) when N > O -> + Version; +lowest_protocol_version({M, _}, Version = {M, _}) -> + Version; +lowest_protocol_version(Version = {M,_}, {N, _}) when M > N -> + Version; +lowest_protocol_version(_,Version) -> + Version. +%%-------------------------------------------------------------------- +-spec highest_protocol_version([tls_version()]) -> tls_version(). +%% +%% Description: Highest protocol version present in a list +%%-------------------------------------------------------------------- +highest_protocol_version([Ver | Vers]) -> + highest_protocol_version(Ver, Vers). + +highest_protocol_version(Version, []) -> + Version; +highest_protocol_version(Version = {N, M}, [{N, O} | Rest]) when M < O -> + highest_protocol_version(Version, Rest); +highest_protocol_version({M, _}, [Version = {M, _} | Rest]) -> + highest_protocol_version(Version, Rest); +highest_protocol_version(Version = {M,_}, [{N,_} | Rest]) when M < N -> + highest_protocol_version(Version, Rest); +highest_protocol_version(_, [Version | Rest]) -> + highest_protocol_version(Version, Rest). + +%%-------------------------------------------------------------------- +-spec get_dtls_records(binary(), binary()) -> {[binary()], binary()} | #alert{}. +%% +%% Description: Given old buffer and new data from UDP/SCTP, packs up a records +%% and returns it as a list of tls_compressed binaries also returns leftover +%% data +%%-------------------------------------------------------------------- +get_dtls_records(Data, <<>>) -> + get_dtls_records_aux(Data, []); +get_dtls_records(Data, Buffer) -> + get_dtls_records_aux(list_to_binary([Buffer, Data]), []). + +get_dtls_records_aux(<>, + Acc) -> + get_dtls_records_aux(Rest, [#ssl_tls{type = ?APPLICATION_DATA, + version = {MajVer, MinVer}, + epoch = Epoch, record_seq = SequenceNumber, + fragment = Data} | Acc]); +get_dtls_records_aux(<>, Acc) when MajVer >= 128 -> + get_dtls_records_aux(Rest, [#ssl_tls{type = ?HANDSHAKE, + version = {MajVer, MinVer}, + epoch = Epoch, record_seq = SequenceNumber, + fragment = Data} | Acc]); +get_dtls_records_aux(<>, Acc) -> + get_dtls_records_aux(Rest, [#ssl_tls{type = ?ALERT, + version = {MajVer, MinVer}, + epoch = Epoch, record_seq = SequenceNumber, + fragment = Data} | Acc]); +get_dtls_records_aux(<>, + Acc) -> + get_dtls_records_aux(Rest, [#ssl_tls{type = ?CHANGE_CIPHER_SPEC, + version = {MajVer, MinVer}, + epoch = Epoch, record_seq = SequenceNumber, + fragment = Data} | Acc]); + +get_dtls_records_aux(<<0:1, _CT:7, ?BYTE(_MajVer), ?BYTE(_MinVer), + ?UINT16(Length), _/binary>>, + _Acc) when Length > ?MAX_CIPHER_TEXT_LENGTH -> + ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); + +get_dtls_records_aux(<<1:1, Length0:15, _/binary>>,_Acc) + when Length0 > ?MAX_CIPHER_TEXT_LENGTH -> + ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); + +get_dtls_records_aux(Data, Acc) -> + case size(Data) =< ?MAX_CIPHER_TEXT_LENGTH + ?INITIAL_BYTES of + true -> + {lists:reverse(Acc), Data}; + false -> + ?ALERT_REC(?FATAL, ?UNEXPECTED_MESSAGE) + end. + +%%-------------------------------------------------------------------- +-spec supported_protocol_versions() -> [tls_version()]. +%% +%% Description: Protocol versions supported +%%-------------------------------------------------------------------- +supported_protocol_versions() -> + Fun = fun(Version) -> + protocol_version(Version) + end, + case application:get_env(ssl, dtls_protocol_version) of + undefined -> + lists:map(Fun, supported_protocol_versions([])); + {ok, []} -> + lists:map(Fun, supported_protocol_versions([])); + {ok, Vsns} when is_list(Vsns) -> + supported_protocol_versions(Vsns); + {ok, Vsn} -> + supported_protocol_versions([Vsn]) + end. + +supported_protocol_versions([]) -> + Vsns = supported_connection_protocol_versions([]), + application:set_env(ssl, dtls_protocol_version, Vsns), + Vsns; + +supported_protocol_versions([_|_] = Vsns) -> + Vsns. + +supported_connection_protocol_versions([]) -> + ?ALL_DATAGRAM_SUPPORTED_VERSIONS. + +%%-------------------------------------------------------------------- +-spec is_acceptable_version(tls_version(), Supported :: [tls_version()]) -> boolean(). +%% +%% Description: ssl version 2 is not acceptable security risks are too big. +%% +%%-------------------------------------------------------------------- +is_acceptable_version(Version, Versions) -> + lists:member(Version, Versions). + +%%-------------------------------------------------------------------- +-spec clear_previous_epoch(#connection_states{}) -> + #connection_states{}. +%% +%% Description: Advance to min_read_epoch to the current read epoch. +%%-------------------------------------------------------------------- +clear_previous_epoch(States = + #connection_states{current_read = Current}) -> + States#connection_states{min_read_epoch = Current#connection_state.epoch}. + + + +decipher(TLS=#ssl_tls{type=Type, version=Version={254, _}, + epoch = Epoch, sequence = SeqNo, + fragment=Fragment}, CS0) -> + SP = CS0#connection_state.security_parameters, + BCA = SP#security_parameters.bulk_cipher_algorithm, + HashSz = SP#security_parameters.hash_size, + CipherS0 = CS0#connection_state.cipher_state, + case ssl_cipher:decipher(BCA, HashSz, CipherS0, Fragment, Version) of + {T, Mac, CipherS1} -> + CS1 = CS0#connection_state{cipher_state = CipherS1}, + TLength = size(T), + MacHash = hash_with_seqno(CS1, Type, Version, Epoch, SeqNo, TLength, T), + case is_correct_mac(Mac, MacHash) of + true -> + {TLS#ssl_tls{fragment = T}, CS1}; + false -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC) + end; + #alert{} = Alert -> + Alert + end. + +hash_with_seqno(#connection_state{mac_secret = MacSecret, + security_parameters = + SecPars}, + Type, Version = {254, _}, + Epoch, SeqNo, Length, Fragment) -> + mac_hash(Version, + SecPars#security_parameters.mac_algorithm, + MacSecret, (Epoch bsl 48) + SeqNo, Type, + Length, Fragment). + +hash_and_bump_seqno(#connection_state{epoch = Epoch, + sequence_number = SeqNo, + mac_secret = MacSecret, + security_parameters = + SecPars} = CS0, + Type, Version = {254, _}, Length, Fragment) -> + Hash = mac_hash(Version, + SecPars#security_parameters.mac_algorithm, + MacSecret, (Epoch bsl 48) + SeqNo, Type, + Length, Fragment), + {Hash, CS0#connection_state{sequence_number = SeqNo+1}}. diff --git a/lib/ssl/src/dtls_record.hrl b/lib/ssl/src/dtls_record.hrl index e935d84bdf..c50550cc28 100644 --- a/lib/ssl/src/dtls_record.hrl +++ b/lib/ssl/src/dtls_record.hrl @@ -28,6 +28,18 @@ -include("ssl_record.hrl"). %% Common TLS and DTLS records and Constantes +-define(INITIAL_BYTES, 5). + +-record(connection_states, { + min_read_epoch, + previous_read, + current_read, + pending_read, + previous_write, + current_write, + pending_write + }). + %% Used to handle tls_plain_text, tls_compressed and tls_cipher_text -record(ssl_tls, { diff --git a/lib/ssl/src/ssl_record.hrl b/lib/ssl/src/ssl_record.hrl index 2fd17f9c35..8a6a211553 100644 --- a/lib/ssl/src/ssl_record.hrl +++ b/lib/ssl/src/ssl_record.hrl @@ -29,12 +29,17 @@ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%% Connection states - RFC 4346 section 6.1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% - --record(connection_states, { - current_read, - pending_read, - current_write, - pending_write +-record(connection_state, { + security_parameters, + compression_state, + cipher_state, + mac_secret, + epoch, %% Only used by DTLS + sequence_number, + %% RFC 5746 + secure_renegotiation, + client_verify_data, + server_verify_data }). -record(security_parameters, { @@ -56,18 +61,6 @@ exportable % boolean }). --record(connection_state, { - security_parameters, - compression_state, - cipher_state, - mac_secret, - sequence_number, - %% RFC 5746 - secure_renegotiation, - client_verify_data, - server_verify_data - }). - -define(MAX_SEQENCE_NUMBER, 18446744073709552000). %% math:pow(2, 64) - 1 = 1.8446744073709552e19 %% Sequence numbers can not wrap so when max is about to be reached we should renegotiate. %% We will renegotiate a little before so that there will be sequence numbers left diff --git a/lib/ssl/src/tls_record.hrl b/lib/ssl/src/tls_record.hrl index c9350fa137..0e3552bafa 100644 --- a/lib/ssl/src/tls_record.hrl +++ b/lib/ssl/src/tls_record.hrl @@ -27,6 +27,12 @@ -define(tls_record, true). -include("ssl_record.hrl"). %% Common TLS and DTLS records and Constantes +-record(connection_states, { + current_read, + pending_read, + current_write, + pending_write + }). %% Used to handle tls_plain_text, tls_compressed and tls_cipher_text -- cgit v1.2.3