diff options
Diffstat (limited to 'lib/ssl/src/tls_record_1_3.erl')
-rw-r--r-- | lib/ssl/src/tls_record_1_3.erl | 281 |
1 files changed, 281 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..1681babed9 --- /dev/null +++ b/lib/ssl/src/tls_record_1_3.erl @@ -0,0 +1,281 @@ +%% +%% %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 = encode_plain_text(Data, Write0), + {CipherText, Write} = encode_tls_cipher_text(CipherFragment, Write0), + {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 := #cipher_state{key = Key, + iv = IV, + tag_len = TagLen}, + security_parameters := + #security_parameters{ + cipher_type = ?AEAD, + bulk_cipher_algorithm = + BulkCipherAlgo} + } = ReadState0} = ConnectionStates0) -> + case decipher_aead(CipherFragment, BulkCipherAlgo, Key, Seq, IV, TagLen) of + #alert{} = Alert -> + Alert; + PlainFragment -> + ConnectionStates = + ConnectionStates0#{current_read => + ReadState0#{sequence_number => Seq + 1}}, + {decode_inner_plaintext(PlainFragment), ConnectionStates} + end; +decode_cipher_text(#ssl_tls{type = Type, + version = ?LEGACY_VERSION, + fragment = CipherFragment}, + #{current_read := + #{security_parameters := + #security_parameters{ + cipher_suite = ?TLS_NULL_WITH_NULL_NULL} + }} = ConnnectionStates0) -> + {#ssl_tls{type = Type, + version = {3,4}, %% Internally use real version + fragment = CipherFragment}, ConnnectionStates0}; +decode_cipher_text(#ssl_tls{type = Type}, _) -> + %% Version mismatch is already asserted + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, {record_type_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 := #cipher_state{key= Key, + iv = IV, + tag_len = TagLen}, + sequence_number := Seq, + security_parameters := + #security_parameters{ + cipher_type = ?AEAD, + bulk_cipher_algorithm = BulkCipherAlgo} + }) -> + PlainText = [Data, Type, Zeros], + Encoded = cipher_aead(PlainText, BulkCipherAlgo, Key, Seq, IV, TagLen), + #tls_cipher_text{opaque_type = 23, %% 23 (application_data) for outward compatibility + legacy_version = {3,3}, + encoded_record = Encoded}; +encode_plain_text(#inner_plaintext{ + content = Data, + type = Type + }, #{security_parameters := + #security_parameters{ + cipher_suite = ?TLS_NULL_WITH_NULL_NULL} + }) -> + %% RFC8446 - 5.1. Record Layer + %% When record protection has not yet been engaged, TLSPlaintext + %% structures are written directly onto the wire. + #tls_cipher_text{opaque_type = Type, + legacy_version = {3,3}, + encoded_record = Data}; + +encode_plain_text(_, CS) -> + exit({cs, CS}). + +additional_data(Length) -> + <<?BYTE(?OPAQUE_TYPE), ?BYTE(3), ?BYTE(3),?UINT16(Length)>>. + +%% The per-record nonce for the AEAD construction is formed as +%% follows: +%% +%% 1. The 64-bit record sequence number is encoded in network byte +%% order and padded to the left with zeros to iv_length. +%% +%% 2. The padded sequence number is XORed with either the static +%% client_write_iv or server_write_iv (depending on the role). +%% +%% The resulting quantity (of length iv_length) is used as the +%% per-record nonce. +nonce(Seq, IV) -> + Padding = binary:copy(<<0>>, byte_size(IV) - 8), + crypto:exor(<<Padding/binary,?UINT64(Seq)>>, IV). + +cipher_aead(Fragment, BulkCipherAlgo, Key, Seq, IV, TagLen) -> + AAD = additional_data(erlang:iolist_size(Fragment) + TagLen), + Nonce = nonce(Seq, IV), + {Content, CipherTag} = + ssl_cipher:aead_encrypt(BulkCipherAlgo, Key, Nonce, Fragment, AAD), + <<Content/binary, CipherTag/binary>>. + +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(CipherFragment, BulkCipherAlgo, Key, Seq, IV, TagLen) -> + try + AAD = additional_data(erlang:iolist_size(CipherFragment)), + Nonce = nonce(Seq, IV), + {CipherText, CipherTag} = aead_ciphertext_split(CipherFragment, TagLen), + case ssl_cipher:aead_decrypt(BulkCipherAlgo, Key, Nonce, CipherText, CipherTag, AAD) of + Content when is_binary(Content) -> + Content; + _ -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, decryption_failed) + end + catch + _:_ -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, decryption_failed) + end. + + +aead_ciphertext_split(CipherTextFragment, TagLen) + when is_binary(CipherTextFragment) -> + CipherLen = erlang:byte_size(CipherTextFragment) - TagLen, + <<CipherText:CipherLen/bytes, CipherTag:TagLen/bytes>> = CipherTextFragment, + {CipherText, CipherTag}; +aead_ciphertext_split(CipherTextFragment, TagLen) + when is_list(CipherTextFragment) -> + CipherLen = erlang:iolist_size(CipherTextFragment) - TagLen, + <<CipherText:CipherLen/bytes, CipherTag:TagLen/bytes>> = + erlang:iolist_to_binary(CipherTextFragment), + {CipherText, CipherTag}. + +decode_inner_plaintext(PlainText) -> + case binary:last(PlainText) of + 0 -> + decode_inner_plaintext(init_binary(PlainText)); + Type when Type =:= ?APPLICATION_DATA orelse + Type =:= ?HANDSHAKE orelse + Type =:= ?ALERT -> + #ssl_tls{type = Type, + version = {3,4}, %% Internally use real version + fragment = init_binary(PlainText)}; + _Else -> + ?ALERT_REC(?FATAL, ?UNEXPECTED_MESSAGE, empty_alert) + end. + +init_binary(B) -> + {Init, _} = + split_binary(B, byte_size(B) - 1), + Init. |