diff options
Diffstat (limited to 'lib/ssl/src/tls_record.erl')
| -rw-r--r-- | lib/ssl/src/tls_record.erl | 380 |
1 files changed, 210 insertions, 170 deletions
diff --git a/lib/ssl/src/tls_record.erl b/lib/ssl/src/tls_record.erl index 5331dd1303..aa8a2aa334 100644 --- a/lib/ssl/src/tls_record.erl +++ b/lib/ssl/src/tls_record.erl @@ -34,10 +34,9 @@ %% Handling of incoming data -export([get_tls_records/2, init_connection_states/2]). -%% Decoding --export([decode_cipher_text/3]). - -%% Encoding +%% Encoding TLS records +-export([encode_handshake/3, encode_alert_record/3, + encode_change_cipher_spec/2, encode_data/3]). -export([encode_plain_text/4]). %% Protocol version handling @@ -46,6 +45,9 @@ is_higher/2, supported_protocol_versions/0, is_acceptable_version/1, is_acceptable_version/2]). +%% Decoding +-export([decode_cipher_text/3]). + -export_type([tls_version/0, tls_atom_version/0]). -type tls_version() :: ssl_record:ssl_version(). @@ -85,152 +87,61 @@ get_tls_records(Data, <<>>) -> get_tls_records(Data, Buffer) -> get_tls_records_aux(list_to_binary([Buffer, Data]), []). -get_tls_records_aux(<<?BYTE(?APPLICATION_DATA),?BYTE(MajVer),?BYTE(MinVer), - ?UINT16(Length), Data:Length/binary, Rest/binary>>, - Acc) -> - get_tls_records_aux(Rest, [#ssl_tls{type = ?APPLICATION_DATA, - version = {MajVer, MinVer}, - fragment = Data} | Acc]); -get_tls_records_aux(<<?BYTE(?HANDSHAKE),?BYTE(MajVer),?BYTE(MinVer), - ?UINT16(Length), - Data:Length/binary, Rest/binary>>, Acc) -> - get_tls_records_aux(Rest, [#ssl_tls{type = ?HANDSHAKE, - version = {MajVer, MinVer}, - fragment = Data} | Acc]); -get_tls_records_aux(<<?BYTE(?ALERT),?BYTE(MajVer),?BYTE(MinVer), - ?UINT16(Length), Data:Length/binary, - Rest/binary>>, Acc) -> - get_tls_records_aux(Rest, [#ssl_tls{type = ?ALERT, - version = {MajVer, MinVer}, - fragment = Data} | Acc]); -get_tls_records_aux(<<?BYTE(?CHANGE_CIPHER_SPEC),?BYTE(MajVer),?BYTE(MinVer), - ?UINT16(Length), Data:Length/binary, Rest/binary>>, - Acc) -> - get_tls_records_aux(Rest, [#ssl_tls{type = ?CHANGE_CIPHER_SPEC, - version = {MajVer, MinVer}, - fragment = Data} | Acc]); -%% Matches an ssl v2 client hello message. -%% The server must be able to receive such messages, from clients that -%% are willing to use ssl v3 or higher, but have ssl v2 compatibility. -get_tls_records_aux(<<1:1, Length0:15, Data0:Length0/binary, Rest/binary>>, - Acc) -> - case Data0 of - <<?BYTE(?CLIENT_HELLO), ?BYTE(MajVer), ?BYTE(MinVer), _/binary>> -> - Length = Length0-1, - <<?BYTE(_), Data1:Length/binary>> = Data0, - Data = <<?BYTE(?CLIENT_HELLO), ?UINT24(Length), Data1/binary>>, - get_tls_records_aux(Rest, [#ssl_tls{type = ?HANDSHAKE, - version = {MajVer, MinVer}, - fragment = Data} | Acc]); - _ -> - ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE) - - end; - -get_tls_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_tls_records_aux(<<1:1, Length0:15, _/binary>>,_Acc) - when Length0 > ?MAX_CIPHER_TEXT_LENGTH -> - ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); +%%-------------------------------------------------------------------- +-spec encode_handshake(iolist(), tls_version(), ssl_record:connection_states()) -> + {iolist(), ssl_record: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) -> + 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. -get_tls_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 encode_alert_record(#alert{}, tls_version(), ssl_record:connection_states()) -> + {iolist(), ssl_record: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). -encode_plain_text(Type, Version, Data, - #{current_write := - #{sequence_number := Seq, - compression_state := CompS0, - security_parameters := - #security_parameters{ - cipher_type = ?AEAD, - compression_algorithm = CompAlg} - }= WriteState0} = ConnectionStates) -> - {Comp, CompS1} = ssl_record:compress(CompAlg, Data, CompS0), - WriteState1 = WriteState0#{compression_state => CompS1}, - AAD = calc_aad(Type, Version, WriteState1), - {CipherFragment, WriteState} = ssl_record:cipher_aead(Version, Comp, WriteState1, AAD), - CipherText = encode_tls_cipher_text(Type, Version, CipherFragment), - {CipherText, ConnectionStates#{current_write => WriteState#{sequence_number => Seq +1}}}; - -encode_plain_text(Type, Version, Data, - #{current_write := - #{sequence_number := Seq, - compression_state := CompS0, - security_parameters := - #security_parameters{compression_algorithm = CompAlg} - }= WriteState0} = ConnectionStates) -> - {Comp, CompS1} = ssl_record:compress(CompAlg, Data, CompS0), - WriteState1 = WriteState0#{compression_state => CompS1}, - MacHash = calc_mac_hash(Type, Version, Comp, WriteState1), - {CipherFragment, WriteState} = ssl_record:cipher(Version, Comp, WriteState1, MacHash), - CipherText = encode_tls_cipher_text(Type, Version, CipherFragment), - {CipherText, ConnectionStates#{current_write => WriteState#{sequence_number => Seq +1}}}; -encode_plain_text(_,_,_, CS) -> - exit({cs, CS}). +%%-------------------------------------------------------------------- +-spec encode_change_cipher_spec(tls_version(), ssl_record:connection_states()) -> + {iolist(), ssl_record: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, ?byte(?CHANGE_CIPHER_SPEC_PROTO), ConnectionStates). %%-------------------------------------------------------------------- --spec decode_cipher_text(#ssl_tls{}, ssl_record:connection_states(), boolean()) -> - {#ssl_tls{}, ssl_record:connection_states()}| #alert{}. +-spec encode_data(binary(), tls_version(), ssl_record:connection_states()) -> + {iolist(), ssl_record:connection_states()}. %% -%% Description: Decode cipher text +%% Description: Encodes data to send on the ssl-socket. %%-------------------------------------------------------------------- -decode_cipher_text(#ssl_tls{type = Type, version = Version, - fragment = CipherFragment} = CipherText, - #{current_read := - #{compression_state := CompressionS0, - sequence_number := Seq, - security_parameters := - #security_parameters{ - cipher_type = ?AEAD, - compression_algorithm = CompAlg} - } = ReadState0} = ConnnectionStates0, _) -> - AAD = calc_aad(Type, Version, ReadState0), - case ssl_record:decipher_aead(Version, CipherFragment, ReadState0, AAD) of - {PlainFragment, ReadState1} -> - {Plain, CompressionS1} = ssl_record:uncompress(CompAlg, - PlainFragment, CompressionS0), - ConnnectionStates = ConnnectionStates0#{ - current_read => ReadState1#{sequence_number => Seq + 1, - compression_state => CompressionS1}}, - {CipherText#ssl_tls{fragment = Plain}, ConnnectionStates}; - #alert{} = Alert -> - Alert - end; +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). + -decode_cipher_text(#ssl_tls{type = Type, version = Version, - fragment = CipherFragment} = CipherText, - #{current_read := - #{compression_state := CompressionS0, - sequence_number := Seq, - security_parameters := - #security_parameters{compression_algorithm = CompAlg} - } = ReadState0} = ConnnectionStates0, PaddingCheck) -> - case ssl_record:decipher(Version, CipherFragment, ReadState0, PaddingCheck) of - {PlainFragment, Mac, ReadState1} -> - MacHash = calc_mac_hash(Type, Version, PlainFragment, ReadState1), - case ssl_record:is_correct_mac(Mac, MacHash) of - true -> - {Plain, CompressionS1} = ssl_record:uncompress(CompAlg, - PlainFragment, CompressionS0), - ConnnectionStates = ConnnectionStates0#{ - current_read => ReadState1#{ - sequence_number => Seq + 1, - compression_state => CompressionS1}}, - {CipherText#ssl_tls{fragment = Plain}, ConnnectionStates}; - false -> - ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC) - end; - #alert{} = Alert -> - Alert - end. %%-------------------------------------------------------------------- -spec protocol_version(tls_atom_version() | tls_version()) -> tls_version() | tls_atom_version(). @@ -401,6 +312,70 @@ initial_connection_state(ConnectionEnd, BeastMitigation) -> server_verify_data => undefined }. +get_tls_records_aux(<<?BYTE(?APPLICATION_DATA),?BYTE(MajVer),?BYTE(MinVer), + ?UINT16(Length), Data:Length/binary, Rest/binary>>, + Acc) -> + get_tls_records_aux(Rest, [#ssl_tls{type = ?APPLICATION_DATA, + version = {MajVer, MinVer}, + fragment = Data} | Acc]); +get_tls_records_aux(<<?BYTE(?HANDSHAKE),?BYTE(MajVer),?BYTE(MinVer), + ?UINT16(Length), + Data:Length/binary, Rest/binary>>, Acc) -> + get_tls_records_aux(Rest, [#ssl_tls{type = ?HANDSHAKE, + version = {MajVer, MinVer}, + fragment = Data} | Acc]); +get_tls_records_aux(<<?BYTE(?ALERT),?BYTE(MajVer),?BYTE(MinVer), + ?UINT16(Length), Data:Length/binary, + Rest/binary>>, Acc) -> + get_tls_records_aux(Rest, [#ssl_tls{type = ?ALERT, + version = {MajVer, MinVer}, + fragment = Data} | Acc]); +get_tls_records_aux(<<?BYTE(?CHANGE_CIPHER_SPEC),?BYTE(MajVer),?BYTE(MinVer), + ?UINT16(Length), Data:Length/binary, Rest/binary>>, + Acc) -> + get_tls_records_aux(Rest, [#ssl_tls{type = ?CHANGE_CIPHER_SPEC, + version = {MajVer, MinVer}, + fragment = Data} | Acc]); +%% Matches an ssl v2 client hello message. +%% The server must be able to receive such messages, from clients that +%% are willing to use ssl v3 or higher, but have ssl v2 compatibility. +get_tls_records_aux(<<1:1, Length0:15, Data0:Length0/binary, Rest/binary>>, + Acc) -> + case Data0 of + <<?BYTE(?CLIENT_HELLO), ?BYTE(MajVer), ?BYTE(MinVer), _/binary>> -> + Length = Length0-1, + <<?BYTE(_), Data1:Length/binary>> = Data0, + Data = <<?BYTE(?CLIENT_HELLO), ?UINT24(Length), Data1/binary>>, + get_tls_records_aux(Rest, [#ssl_tls{type = ?HANDSHAKE, + version = {MajVer, MinVer}, + fragment = Data} | Acc]); + _ -> + ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE) + + end; + +get_tls_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_tls_records_aux(<<1:1, Length0:15, _/binary>>,_Acc) + when Length0 > ?MAX_CIPHER_TEXT_LENGTH -> + ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); + +get_tls_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. + +encode_plain_text(Type, Version, Data, #{current_write := Write0} = ConnectionStates) -> + {CipherFragment, Write1} = ssl_record:encode_plain_text(Type, Version, Data, Write0), + {CipherText, Write} = encode_tls_cipher_text(Type, Version, CipherFragment, Write1), + {CipherText, ConnectionStates#{current_write => Write}}. + lowest_list_protocol_version(Ver, []) -> Ver; lowest_list_protocol_version(Ver1, [Ver2 | Rest]) -> @@ -411,20 +386,10 @@ highest_list_protocol_version(Ver, []) -> highest_list_protocol_version(Ver1, [Ver2 | Rest]) -> highest_list_protocol_version(highest_protocol_version(Ver1, Ver2), Rest). -encode_tls_cipher_text(Type, {MajVer, MinVer}, Fragment) -> +encode_tls_cipher_text(Type, {MajVer, MinVer}, Fragment, #{sequence_number := Seq} = Write) -> Length = erlang:iolist_size(Fragment), - [<<?BYTE(Type), ?BYTE(MajVer), ?BYTE(MinVer), ?UINT16(Length)>>, Fragment]. - - -mac_hash({_,_}, ?NULL, _MacSecret, _SeqNo, _Type, - _Length, _Fragment) -> - <<>>; -mac_hash({3, 0}, MacAlg, MacSecret, SeqNo, Type, Length, Fragment) -> - ssl_v3:mac_hash(MacAlg, MacSecret, SeqNo, Type, Length, Fragment); -mac_hash({3, N} = Version, MacAlg, MacSecret, SeqNo, Type, Length, Fragment) - when N =:= 1; N =:= 2; N =:= 3 -> - tls_v1:mac_hash(MacAlg, MacSecret, SeqNo, Type, Version, - Length, Fragment). + {[<<?BYTE(Type), ?BYTE(MajVer), ?BYTE(MinVer), ?UINT16(Length)>>, Fragment], + Write#{sequence_number => Seq +1}}. highest_protocol_version() -> highest_protocol_version(supported_protocol_versions()). @@ -432,21 +397,96 @@ highest_protocol_version() -> lowest_protocol_version() -> lowest_protocol_version(supported_protocol_versions()). - sufficient_tlsv1_2_crypto_support() -> CryptoSupport = crypto:supports(), proplists:get_bool(sha256, proplists:get_value(hashs, CryptoSupport)). -calc_mac_hash(Type, Version, - PlainFragment, #{sequence_number := SeqNo, - mac_secret := MacSecret, - security_parameters:= - SecPars}) -> - Length = erlang:iolist_size(PlainFragment), - mac_hash(Version, SecPars#security_parameters.mac_algorithm, - MacSecret, SeqNo, Type, - Length, PlainFragment). - -calc_aad(Type, {MajVer, MinVer}, - #{sequence_number := SeqNo}) -> - <<SeqNo:64/integer, ?BYTE(Type), ?BYTE(MajVer), ?BYTE(MinVer)>>. +encode_iolist(Type, Data, Version, ConnectionStates0) -> + {ConnectionStates, EncodedMsg} = + lists:foldl(fun(Text, {CS0, Encoded}) -> + {Enc, CS1} = + 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. + +%%-------------------------------------------------------------------- +-spec decode_cipher_text(#ssl_tls{}, ssl_record:connection_states(), boolean()) -> + {#ssl_tls{}, ssl_record:connection_states()}| #alert{}. +%% +%% Description: Decode cipher text +%%-------------------------------------------------------------------- +decode_cipher_text(#ssl_tls{type = Type, version = Version, + fragment = CipherFragment} = CipherText, + #{current_read := + #{compression_state := CompressionS0, + sequence_number := Seq, + security_parameters := + #security_parameters{ + cipher_type = ?AEAD, + compression_algorithm = CompAlg} + } = ReadState0} = ConnnectionStates0, _) -> + AAD = ssl_cipher:calc_aad(Type, Version, ReadState0), + case ssl_record:decipher_aead(Version, CipherFragment, ReadState0, AAD) of + {PlainFragment, ReadState1} -> + {Plain, CompressionS1} = ssl_record:uncompress(CompAlg, + PlainFragment, CompressionS0), + ConnnectionStates = ConnnectionStates0#{ + current_read => ReadState1#{sequence_number => Seq + 1, + compression_state => CompressionS1}}, + {CipherText#ssl_tls{fragment = Plain}, ConnnectionStates}; + #alert{} = Alert -> + Alert + end; + +decode_cipher_text(#ssl_tls{type = Type, version = Version, + fragment = CipherFragment} = CipherText, + #{current_read := + #{compression_state := CompressionS0, + sequence_number := Seq, + security_parameters := + #security_parameters{compression_algorithm = CompAlg} + } = ReadState0} = ConnnectionStates0, PaddingCheck) -> + case ssl_record:decipher(Version, CipherFragment, ReadState0, PaddingCheck) of + {PlainFragment, Mac, ReadState1} -> + MacHash = ssl_cipher:calc_mac_hash(Type, Version, PlainFragment, ReadState1), + case ssl_record:is_correct_mac(Mac, MacHash) of + true -> + {Plain, CompressionS1} = ssl_record:uncompress(CompAlg, + PlainFragment, CompressionS0), + ConnnectionStates = ConnnectionStates0#{ + current_read => ReadState1#{ + sequence_number => Seq + 1, + compression_state => CompressionS1}}, + {CipherText#ssl_tls{fragment = Plain}, ConnnectionStates}; + false -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC) + end; + #alert{} = Alert -> + Alert + end. |