diff options
Diffstat (limited to 'lib/ssl/src/tls_record_1_3.erl')
-rw-r--r-- | lib/ssl/src/tls_record_1_3.erl | 168 |
1 files changed, 81 insertions, 87 deletions
diff --git a/lib/ssl/src/tls_record_1_3.erl b/lib/ssl/src/tls_record_1_3.erl index d424336187..1681babed9 100644 --- a/lib/ssl/src/tls_record_1_3.erl +++ b/lib/ssl/src/tls_record_1_3.erl @@ -76,8 +76,8 @@ encode_data(Frag, 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), + CipherFragment = encode_plain_text(Data, Write0), + {CipherText, Write} = encode_tls_cipher_text(CipherFragment, Write0), {CipherText, ConnectionStates#{current_write => Write}}. encode_iolist(Type, Data, ConnectionStates0) -> @@ -105,24 +105,23 @@ decode_cipher_text(#ssl_tls{type = ?OPAQUE_TYPE, fragment = CipherFragment}, #{current_read := #{sequence_number := Seq, - cipher_state := CipherS0, + cipher_state := #cipher_state{key = Key, + iv = IV, + tag_len = TagLen}, security_parameters := #security_parameters{ cipher_type = ?AEAD, bulk_cipher_algorithm = BulkCipherAlgo} } = ReadState0} = ConnectionStates0) -> - AAD = start_additional_data(), - CipherS1 = ssl_cipher:nonce_seed(<<?UINT64(Seq)>>, CipherS0), - case decipher_aead(BulkCipherAlgo, CipherS1, AAD, CipherFragment) of - {PlainFragment, CipherS1} -> + case decipher_aead(CipherFragment, BulkCipherAlgo, Key, Seq, IV, TagLen) of + #alert{} = Alert -> + Alert; + PlainFragment -> ConnectionStates = ConnectionStates0#{current_read => - ReadState0#{cipher_state => CipherS1, - sequence_number => Seq + 1}}, - decode_inner_plaintext(PlainFragment, ConnectionStates); - #alert{} = Alert -> - Alert + ReadState0#{sequence_number => Seq + 1}}, + {decode_inner_plaintext(PlainFragment), ConnectionStates} end; decode_cipher_text(#ssl_tls{type = Type, version = ?LEGACY_VERSION, @@ -137,7 +136,7 @@ decode_cipher_text(#ssl_tls{type = Type, fragment = CipherFragment}, ConnnectionStates0}; decode_cipher_text(#ssl_tls{type = Type}, _) -> %% Version mismatch is already asserted - ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, {record_typ_mismatch, Type}). + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, {record_type_mismatch, Type}). %%-------------------------------------------------------------------- %%% Internal functions @@ -170,62 +169,61 @@ encode_plain_text(#inner_plaintext{ content = Data, type = Type, zeros = Zeros - }, #{cipher_state := CipherS0, + }, #{cipher_state := #cipher_state{key= Key, + iv = IV, + tag_len = TagLen}, 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{opaque_type = Type, - legacy_version = {3,3}, - encoded_record = Encoded}, WriteState}; + 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} - } = WriteState0) -> + }) -> %% 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, + #tls_cipher_text{opaque_type = Type, legacy_version = {3,3}, - encoded_record = Data}, WriteState0}; + encoded_record = Data}; 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). +additional_data(Length) -> + <<?BYTE(?OPAQUE_TYPE), ?BYTE(3), ?BYTE(3),?UINT16(Length)>>. -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}}. +%% 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(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}. +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}, @@ -234,13 +232,14 @@ encode_tls_cipher_text(#tls_cipher_text{opaque_type = Type, {[<<?BYTE(Type), ?BYTE(MajVer), ?BYTE(MinVer), ?UINT16(Length)>>, Encoded], Write#{sequence_number => Seq +1}}. -decipher_aead(Type, #cipher_state{key = Key} = CipherState, AAD0, CipherFragment) -> +decipher_aead(CipherFragment, BulkCipherAlgo, Key, Seq, IV, TagLen) -> 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 + 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, CipherState}; + Content; _ -> ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, decryption_failed) end @@ -249,39 +248,34 @@ decipher_aead(Type, #cipher_state{key = Key} = CipherState, AAD0, CipherFragment ?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. +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}. -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) +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. -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}. +init_binary(B) -> + {Init, _} = + split_binary(B, byte_size(B) - 1), + Init. |