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Diffstat (limited to 'lib/ssl/src/tls_record_1_3.erl')
-rw-r--r-- | lib/ssl/src/tls_record_1_3.erl | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/lib/ssl/src/tls_record_1_3.erl b/lib/ssl/src/tls_record_1_3.erl new file mode 100644 index 0000000000..ff198a09bf --- /dev/null +++ b/lib/ssl/src/tls_record_1_3.erl @@ -0,0 +1,260 @@ +%% +%% %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% + +-module(tls_record_1_3). + +-include("tls_record.hrl"). +-include("tls_record_1_3.hrl"). +-include("ssl_internal.hrl"). +-include("ssl_alert.hrl"). +-include("ssl_cipher.hrl"). + +%% Encoding +-export([encode_handshake/2, encode_alert_record/2, + encode_data/2]). +-export([encode_plain_text/3]). + +%% Decoding +-export([decode_cipher_text/2]). + +%%==================================================================== +%% Encoding +%%==================================================================== + +%%-------------------------------------------------------------------- +-spec encode_handshake(iolist(), ssl_record:connection_states()) -> + {iolist(), ssl_record:connection_states()}. +% +%% Description: Encodes a handshake message to send on the tls-1.3-socket. +%%-------------------------------------------------------------------- +encode_handshake(Frag, ConnectionStates) -> + case iolist_size(Frag) of + N when N > ?MAX_PLAIN_TEXT_LENGTH -> + %% TODO: Consider padding here + Data = split_bin(iolist_to_binary(Frag), ?MAX_PLAIN_TEXT_LENGTH), + encode_iolist(?HANDSHAKE, Data, ConnectionStates); + _ -> + encode_plain_text(?HANDSHAKE, Frag, ConnectionStates) + end. + +%%-------------------------------------------------------------------- +-spec encode_alert_record(#alert{}, 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}, + ConnectionStates) -> + encode_plain_text(?ALERT, <<?BYTE(Level), ?BYTE(Description)>>, + ConnectionStates). +%%-------------------------------------------------------------------- +-spec encode_data(binary(), ssl_record:connection_states()) -> + {iolist(), ssl_record:connection_states()}. +%% +%% Description: Encodes data to send on the ssl-socket. +%%-------------------------------------------------------------------- +encode_data(Frag, ConnectionStates) -> + Data = split_bin(Frag, ?MAX_PLAIN_TEXT_LENGTH, {3,4}), + encode_iolist(?APPLICATION_DATA, Data, ConnectionStates). + +encode_plain_text(Type, Data0, #{current_write := Write0} = ConnectionStates) -> + PadLen = 0, %% TODO where to specify PadLen? + Data = inner_plaintext(Type, Data0, PadLen), + {CipherFragment, Write1} = encode_plain_text(Data, Write0), + {CipherText, Write} = encode_tls_cipher_text(CipherFragment, Write1), + {CipherText, ConnectionStates#{current_write => Write}}. + +encode_iolist(Type, Data, ConnectionStates0) -> + {ConnectionStates, EncodedMsg} = + lists:foldl(fun(Text, {CS0, Encoded}) -> + {Enc, CS1} = + encode_plain_text(Type, Text, CS0), + {CS1, [Enc | Encoded]} + end, {ConnectionStates0, []}, Data), + {lists:reverse(EncodedMsg), ConnectionStates}. + +%%==================================================================== +%% Decoding +%%==================================================================== + +%%-------------------------------------------------------------------- +-spec decode_cipher_text(#ssl_tls{}, ssl_record:connection_states()) -> + {#ssl_tls{}, ssl_record:connection_states()}| #alert{}. +%% +%% Description: Decode cipher text, use legacy type ssl_tls instead of tls_cipher_text +%% in decoding context so that we can reuse the code from erlier versions. +%%-------------------------------------------------------------------- +decode_cipher_text(#ssl_tls{type = ?OPAQUE_TYPE, + version = ?LEGACY_VERSION, + fragment = CipherFragment}, + #{current_read := + #{sequence_number := Seq, + cipher_state := CipherS0, + security_parameters := + #security_parameters{ + cipher_type = ?AEAD, + bulk_cipher_algorithm = + BulkCipherAlgo} + } = ReadState0} = ConnnectionStates0) -> + AAD = start_additional_data(), + CipherS1 = ssl_cipher:nonce_seed(<<?UINT64(Seq)>>, CipherS0), + case decipher_aead(BulkCipherAlgo, CipherS1, AAD, CipherFragment) of + {PlainFragment, CipherS1} -> + ConnnectionStates = + ConnnectionStates0#{current_read => + ReadState0#{cipher_state => CipherS1, + sequence_number => Seq + 1}}, + decode_inner_plaintext(PlainFragment, ConnnectionStates); + #alert{} = Alert -> + Alert + end; +decode_cipher_text(#ssl_tls{type = Type}, _) -> + %% Version mismatch is already asserted + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, {record_typ_mismatch, Type}). + +%%-------------------------------------------------------------------- +%%% Internal functions +%%-------------------------------------------------------------------- +split_bin(Bin, ChunkSize) -> + 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. + +inner_plaintext(Type, Data, Length) -> + #inner_plaintext{ + content = Data, + type = Type, + zeros = zero_padding(Length) + }. +zero_padding(Length)-> + binary:copy(<<?BYTE(0)>>, Length). + +encode_plain_text(#inner_plaintext{ + content = Data, + type = Type, + zeros = Zeros + }, #{cipher_state := CipherS0, + sequence_number := Seq, + security_parameters := + #security_parameters{ + cipher_type = ?AEAD} + } = WriteState0) -> + PlainText = <<Data/binary, ?BYTE(Type), Zeros/binary>>, + AAD = start_additional_data(), + CipherS1 = ssl_cipher:nonce_seed(<<?UINT64(Seq)>>, CipherS0), + {Encoded, WriteState} = cipher_aead(PlainText, WriteState0#{cipher_state => CipherS1}, AAD), + {#tls_cipher_text{encoded_record = Encoded}, WriteState}; +encode_plain_text(_, CS) -> + exit({cs, CS}). + +start_additional_data() -> + {MajVer, MinVer} = ?LEGACY_VERSION, + <<?BYTE(?OPAQUE_TYPE), ?BYTE(MajVer), ?BYTE(MinVer)>>. + +end_additional_data(AAD, Len) -> + <<AAD/binary, ?UINT16(Len)>>. + +nonce(#cipher_state{nonce = Nonce, iv = IV}) -> + Len = size(IV), + crypto:exor(<<Nonce:Len/bytes>>, IV). + +cipher_aead(Fragment, + #{cipher_state := CipherS0, + security_parameters := + #security_parameters{bulk_cipher_algorithm = + BulkCipherAlgo} + } = WriteState0, AAD) -> + {CipherFragment, CipherS1} = + cipher_aead(BulkCipherAlgo, CipherS0, AAD, Fragment), + {CipherFragment, WriteState0#{cipher_state => CipherS1}}. + +cipher_aead(Type, #cipher_state{key=Key} = CipherState, AAD0, Fragment) -> + AAD = end_additional_data(AAD0, erlang:iolist_size(Fragment)), + Nonce = nonce(CipherState), + {Content, CipherTag} = ssl_cipher:aead_encrypt(Type, Key, Nonce, Fragment, AAD), + {<<Content/binary, CipherTag/binary>>, CipherState}. + +encode_tls_cipher_text(#tls_cipher_text{opaque_type = Type, + legacy_version = {MajVer, MinVer}, + encoded_record = Encoded}, #{sequence_number := Seq} = Write) -> + Length = erlang:iolist_size(Encoded), + {[<<?BYTE(Type), ?BYTE(MajVer), ?BYTE(MinVer), ?UINT16(Length)>>, Encoded], + Write#{sequence_number => Seq +1}}. + +decipher_aead(Type, #cipher_state{key = Key} = CipherState, AAD0, CipherFragment) -> + try + Nonce = nonce(CipherState), + {AAD, CipherText, CipherTag} = aead_ciphertext_split(CipherState, CipherFragment, AAD0), + case ssl_cipher:aead_decrypt(Type, Key, Nonce, CipherText, CipherTag, AAD) of + Content when is_binary(Content) -> + {Content, CipherState}; + _ -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, decryption_failed) + end + catch + _:_ -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, decryption_failed) + end. + +aead_ciphertext_split(#cipher_state{tag_len = Len}, CipherTextFragment, AAD) -> + CipherLen = size(CipherTextFragment) - Len, + <<CipherText:CipherLen/bytes, CipherTag:Len/bytes>> = CipherTextFragment, + {end_additional_data(AAD, CipherLen), CipherText, CipherTag}. + +decode_inner_plaintext(PlainText, ConnnectionStates) -> + case remove_padding(PlainText) of + #alert{} = Alert -> + Alert; + {Data, Type} -> + {#ssl_tls{type = Type, + version = {3,4}, %% Internally use real version + fragment = Data}, ConnnectionStates} + end. + +remove_padding(PlainText)-> + case binary:split(PlainText, <<0>>, [global, trim]) of + [] -> + ?ALERT_REC(?FATAL, ?UNEXPECTED_MESSAGE, padding_error); + [Content] -> + Type = binary:last(Content), + split_content(Type, Content, erlang:byte_size(Content) - 1) + end. + +split_content(?HANDSHAKE, _, 0) -> + ?ALERT_REC(?FATAL, ?UNEXPECTED_MESSAGE, empty_handshake); +split_content(?ALERT, _, 0) -> + ?ALERT_REC(?FATAL, ?UNEXPECTED_MESSAGE, empty_alert); +%% For special middlebox compatible case! +split_content(?CHANGE_CIPHER_SPEC, _, 0) -> + ?ALERT_REC(?FATAL, ?UNEXPECTED_MESSAGE, empty_change_cipher_spec); +split_content(?APPLICATION_DATA = Type, _, 0) -> + {Type, <<>>}; +split_content(Type, Content, N) -> + <<Data:N/bytes, ?BYTE(Type)>> = Content, + {Type, Data}. |