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authorIngela Anderton Andin <[email protected]>2018-10-17 11:44:29 +0200
committerIngela Anderton Andin <[email protected]>2018-10-19 18:15:02 +0200
commita9541beba58c494300e55dcfbda288e60a2fb54a (patch)
tree58a5c19452f2bacf4c6ab6f27d52272207fc2a44
parent13baa4384c4c9c49e6d540bc8ae6b8946f2454ed (diff)
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ssl: Refactor AEAD ciphers
TLS-1.3 needs to handle AEAD inputs diffrently than previous versions. Refactor code to facilitate TLS-1.3 additions. Change CHACHA20_POLY1305 NONCE to match RFC 7905. This will be important later when we fix interop with TLS compatible crypto invocation.
-rw-r--r--lib/ssl/src/dtls_record.erl22
-rw-r--r--lib/ssl/src/ssl_cipher.erl88
-rw-r--r--lib/ssl/src/ssl_cipher.hrl3
-rw-r--r--lib/ssl/src/ssl_record.erl79
-rw-r--r--lib/ssl/src/tls_record.erl24
5 files changed, 117 insertions, 99 deletions
diff --git a/lib/ssl/src/dtls_record.erl b/lib/ssl/src/dtls_record.erl
index 9eb0d8e2d7..b7346d3ec8 100644
--- a/lib/ssl/src/dtls_record.erl
+++ b/lib/ssl/src/dtls_record.erl
@@ -499,23 +499,22 @@ encode_dtls_cipher_text(Type, {MajVer, MinVer}, Fragment,
WriteState#{sequence_number => Seq + 1}}.
encode_plain_text(Type, Version, Data, #{compression_state := CompS0,
+ cipher_state := CipherS0,
epoch := Epoch,
sequence_number := Seq,
- cipher_state := CipherS0,
security_parameters :=
#security_parameters{
cipher_type = ?AEAD,
- bulk_cipher_algorithm =
- BulkCipherAlgo,
+ bulk_cipher_algorithm = BCAlg,
compression_algorithm = CompAlg}
} = WriteState0) ->
{Comp, CompS1} = ssl_record:compress(CompAlg, Data, CompS0),
- AAD = calc_aad(Type, Version, Epoch, Seq),
+ AAD = start_additional_data(Type, Version, Epoch, Seq),
+ CipherS = ssl_record:nonce_seed(BCAlg, <<?UINT16(Epoch), ?UINT48(Seq)>>, CipherS0),
+ WriteState = WriteState0#{compression_state => CompS1,
+ cipher_state => CipherS},
TLSVersion = dtls_v1:corresponding_tls_version(Version),
- {CipherFragment, CipherS1} =
- ssl_cipher:cipher_aead(BulkCipherAlgo, CipherS0, Seq, AAD, Comp, TLSVersion),
- {CipherFragment, WriteState0#{compression_state => CompS1,
- cipher_state => CipherS1}};
+ ssl_record:cipher_aead(TLSVersion, Comp, WriteState, AAD);
encode_plain_text(Type, Version, Fragment, #{compression_state := CompS0,
epoch := Epoch,
sequence_number := Seq,
@@ -547,9 +546,10 @@ decode_cipher_text(#ssl_tls{type = Type, version = Version,
BulkCipherAlgo,
compression_algorithm = CompAlg}} = ReadState0,
ConnnectionStates0) ->
- AAD = calc_aad(Type, Version, Epoch, Seq),
+ AAD = start_additional_data(Type, Version, Epoch, Seq),
+ CipherS1 = ssl_record:nonce_seed(BulkCipherAlgo, <<?UINT16(Epoch), ?UINT48(Seq)>>, CipherS0),
TLSVersion = dtls_v1:corresponding_tls_version(Version),
- case ssl_cipher:decipher_aead(BulkCipherAlgo, CipherS0, Seq, AAD, CipherFragment, TLSVersion) of
+ case ssl_record:decipher_aead(BulkCipherAlgo, CipherS1, AAD, CipherFragment, TLSVersion) of
{PlainFragment, CipherState} ->
{Plain, CompressionS1} = ssl_record:uncompress(CompAlg,
PlainFragment, CompressionS0),
@@ -600,7 +600,7 @@ mac_hash({Major, Minor}, MacAlg, MacSecret, Epoch, SeqNo, Type, Length, Fragment
Fragment],
dtls_v1:hmac_hash(MacAlg, MacSecret, Value).
-calc_aad(Type, {MajVer, MinVer}, Epoch, SeqNo) ->
+start_additional_data(Type, {MajVer, MinVer}, Epoch, SeqNo) ->
<<?UINT16(Epoch), ?UINT48(SeqNo), ?BYTE(Type), ?BYTE(MajVer), ?BYTE(MinVer)>>.
%%--------------------------------------------------------------------
diff --git a/lib/ssl/src/ssl_cipher.erl b/lib/ssl/src/ssl_cipher.erl
index b23129dcdd..0e22d63b4b 100644
--- a/lib/ssl/src/ssl_cipher.erl
+++ b/lib/ssl/src/ssl_cipher.erl
@@ -34,7 +34,7 @@
-include_lib("public_key/include/public_key.hrl").
-export([security_parameters/2, security_parameters/3,
- cipher_init/3, decipher/6, cipher/5, decipher_aead/6, cipher_aead/6,
+ cipher_init/3, nonce_seed/2, decipher/6, cipher/5, aead_encrypt/5, aead_decrypt/6,
suites/1, all_suites/1, crypto_support_filters/0,
chacha_suites/1, anonymous_suites/1, psk_suites/1, psk_suites_anon/1,
srp_suites/0, srp_suites_anon/0,
@@ -48,6 +48,8 @@
-type cipher_enum() :: integer().
+-export_type([cipher_enum/0]).
+
%%--------------------------------------------------------------------
-spec security_parameters(ssl_cipher_format:cipher_suite(), #security_parameters{}) ->
#security_parameters{}.
@@ -91,10 +93,15 @@ cipher_init(?RC4, IV, Key) ->
#cipher_state{iv = IV, key = Key, state = State};
cipher_init(?AES_GCM, IV, Key) ->
<<Nonce:64>> = random_bytes(8),
- #cipher_state{iv = IV, key = Key, nonce = Nonce};
+ #cipher_state{iv = IV, key = Key, nonce = Nonce, tag_len = 16};
+cipher_init(?CHACHA20_POLY1305, IV, Key) ->
+ #cipher_state{iv = IV, key = Key, tag_len = 16};
cipher_init(_BCA, IV, Key) ->
#cipher_state{iv = IV, key = Key}.
+nonce_seed(Seed, CipherState) ->
+ CipherState#cipher_state{nonce = Seed}.
+
%%--------------------------------------------------------------------
-spec cipher(cipher_enum(), #cipher_state{}, binary(), iodata(), ssl_record:ssl_version()) ->
{binary(), #cipher_state{}}.
@@ -126,32 +133,16 @@ cipher(?AES_CBC, CipherState, Mac, Fragment, Version) ->
crypto:block_encrypt(aes_cbc256, Key, IV, T)
end, block_size(aes_128_cbc), CipherState, Mac, Fragment, Version).
-%%--------------------------------------------------------------------
--spec cipher_aead(cipher_enum(), #cipher_state{}, integer(), binary(), iodata(), ssl_record:ssl_version()) ->
- {binary(), #cipher_state{}}.
-%%
-%% Description: Encrypts the data and protects associated data (AAD) using chipher
-%% described by cipher_enum() and updating the cipher state
-%% Use for suites that use authenticated encryption with associated data (AEAD)
-%%-------------------------------------------------------------------
-cipher_aead(?AES_GCM, CipherState, SeqNo, AAD, Fragment, Version) ->
- aead_cipher(aes_gcm, CipherState, SeqNo, AAD, Fragment, Version);
-cipher_aead(?CHACHA20_POLY1305, CipherState, SeqNo, AAD, Fragment, Version) ->
- aead_cipher(chacha20_poly1305, CipherState, SeqNo, AAD, Fragment, Version).
-
-aead_cipher(chacha20_poly1305, #cipher_state{key=Key} = CipherState, SeqNo, AAD0, Fragment, _Version) ->
- CipherLen = erlang:iolist_size(Fragment),
- AAD = <<AAD0/binary, ?UINT16(CipherLen)>>,
- Nonce = ?uint64(SeqNo),
- {Content, CipherTag} = crypto:block_encrypt(chacha20_poly1305, Key, Nonce, {AAD, Fragment}),
- {<<Content/binary, CipherTag/binary>>, CipherState};
-aead_cipher(Type, #cipher_state{key=Key, iv = IV0, nonce = Nonce} = CipherState, _SeqNo, AAD0, Fragment, _Version) ->
- CipherLen = erlang:iolist_size(Fragment),
- AAD = <<AAD0/binary, ?UINT16(CipherLen)>>,
- <<Salt:4/bytes, _/binary>> = IV0,
- IV = <<Salt/binary, Nonce:64/integer>>,
- {Content, CipherTag} = crypto:block_encrypt(Type, Key, IV, {AAD, Fragment}),
- {<<Nonce:64/integer, Content/binary, CipherTag/binary>>, CipherState#cipher_state{nonce = Nonce + 1}}.
+aead_encrypt(Type, Key, Nonce, Fragment, AdditionalData) ->
+ crypto:block_encrypt(aead_type(Type), Key, Nonce, {AdditionalData, Fragment}).
+
+aead_decrypt(Type, Key, Nonce, CipherText, CipherTag, AdditionalData) ->
+ crypto:block_decrypt(aead_type(Type), Key, Nonce, {AdditionalData, CipherText, CipherTag}).
+
+aead_type(?AES_GCM) ->
+ aes_gcm;
+aead_type(?CHACHA20_POLY1305) ->
+ chacha20_poly1305.
build_cipher_block(BlockSz, Mac, Fragment) ->
TotSz = byte_size(Mac) + erlang:iolist_size(Fragment) + 1,
@@ -218,19 +209,6 @@ decipher(?AES_CBC, HashSz, CipherState, Fragment, Version, PaddingCheck) ->
crypto:block_decrypt(aes_cbc256, Key, IV, T)
end, CipherState, HashSz, Fragment, Version, PaddingCheck).
-%%--------------------------------------------------------------------
--spec decipher_aead(cipher_enum(), #cipher_state{}, integer(), binary(), binary(), ssl_record:ssl_version()) ->
- {binary(), #cipher_state{}} | #alert{}.
-%%
-%% Description: Decrypts the data and checks the associated data (AAD) MAC using
-%% cipher described by cipher_enum() and updating the cipher state.
-%% Use for suites that use authenticated encryption with associated data (AEAD)
-%%-------------------------------------------------------------------
-decipher_aead(?AES_GCM, CipherState, SeqNo, AAD, Fragment, Version) ->
- aead_decipher(aes_gcm, CipherState, SeqNo, AAD, Fragment, Version);
-decipher_aead(?CHACHA20_POLY1305, CipherState, SeqNo, AAD, Fragment, Version) ->
- aead_decipher(chacha20_poly1305, CipherState, SeqNo, AAD, Fragment, Version).
-
block_decipher(Fun, #cipher_state{key=Key, iv=IV} = CipherState0,
HashSz, Fragment, Version, PaddingCheck) ->
try
@@ -261,34 +239,6 @@ block_decipher(Fun, #cipher_state{key=Key, iv=IV} = CipherState0,
?ALERT_REC(?FATAL, ?BAD_RECORD_MAC, decryption_failed)
end.
-aead_ciphertext_to_state(chacha20_poly1305, SeqNo, _IV, AAD0, Fragment, _Version) ->
- CipherLen = size(Fragment) - 16,
- <<CipherText:CipherLen/bytes, CipherTag:16/bytes>> = Fragment,
- AAD = <<AAD0/binary, ?UINT16(CipherLen)>>,
- Nonce = ?uint64(SeqNo),
- {Nonce, AAD, CipherText, CipherTag};
-aead_ciphertext_to_state(_, _SeqNo, <<Salt:4/bytes, _/binary>>, AAD0, Fragment, _Version) ->
- CipherLen = size(Fragment) - 24,
- <<ExplicitNonce:8/bytes, CipherText:CipherLen/bytes, CipherTag:16/bytes>> = Fragment,
- AAD = <<AAD0/binary, ?UINT16(CipherLen)>>,
- Nonce = <<Salt/binary, ExplicitNonce/binary>>,
- {Nonce, AAD, CipherText, CipherTag}.
-
-aead_decipher(Type, #cipher_state{key = Key, iv = IV} = CipherState,
- SeqNo, AAD0, Fragment, Version) ->
- try
- {Nonce, AAD, CipherText, CipherTag} = aead_ciphertext_to_state(Type, SeqNo, IV, AAD0, Fragment, Version),
- case crypto:block_decrypt(Type, Key, Nonce, {AAD, CipherText, CipherTag}) 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.
-
%%--------------------------------------------------------------------
-spec suites(ssl_record:ssl_version()) -> [ssl_cipher_format:cipher_suite()].
%%
diff --git a/lib/ssl/src/ssl_cipher.hrl b/lib/ssl/src/ssl_cipher.hrl
index ba6a98b92a..2371e8bd32 100644
--- a/lib/ssl/src/ssl_cipher.hrl
+++ b/lib/ssl/src/ssl_cipher.hrl
@@ -48,7 +48,8 @@
iv,
key,
state,
- nonce
+ nonce,
+ tag_len
}).
%%% TLS_NULL_WITH_NULL_NULL is specified and is the initial state of a
diff --git a/lib/ssl/src/ssl_record.erl b/lib/ssl/src/ssl_record.erl
index 659e1485ac..d31e429283 100644
--- a/lib/ssl/src/ssl_record.erl
+++ b/lib/ssl/src/ssl_record.erl
@@ -45,7 +45,7 @@
-export([compress/3, uncompress/3, compressions/0]).
%% Payload encryption/decryption
--export([cipher/4, decipher/4, cipher_aead/4, is_correct_mac/2]).
+-export([cipher/4, decipher/4, cipher_aead/4, decipher_aead/5, is_correct_mac/2, nonce_seed/3]).
-export_type([ssl_version/0, ssl_atom_version/0, connection_states/0, connection_state/0]).
@@ -306,22 +306,20 @@ cipher(Version, Fragment,
{CipherFragment, CipherS1} =
ssl_cipher:cipher(BulkCipherAlgo, CipherS0, MacHash, Fragment, Version),
{CipherFragment, WriteState0#{cipher_state => CipherS1}}.
-%% %%--------------------------------------------------------------------
-%% -spec cipher_aead(ssl_version(), iodata(), connection_state(), MacHash::binary()) ->
-%% {CipherFragment::binary(), connection_state()}.
-%% %%
-%% %% Description: Payload encryption
+%%--------------------------------------------------------------------
+-spec cipher_aead(ssl_version(), iodata(), connection_state(), AAD::binary()) ->
+ {CipherFragment::binary(), connection_state()}.
+
+%% Description: Payload encryption
%% %%--------------------------------------------------------------------
cipher_aead(Version, Fragment,
#{cipher_state := CipherS0,
- sequence_number := SeqNo,
security_parameters :=
#security_parameters{bulk_cipher_algorithm =
BulkCipherAlgo}
} = WriteState0, AAD) ->
-
{CipherFragment, CipherS1} =
- ssl_cipher:cipher_aead(BulkCipherAlgo, CipherS0, SeqNo, AAD, Fragment, Version),
+ cipher_aead(BulkCipherAlgo, CipherS0, AAD, Fragment, Version),
{CipherFragment, WriteState0#{cipher_state => CipherS1}}.
%%--------------------------------------------------------------------
@@ -344,10 +342,39 @@ decipher(Version, CipherFragment,
#alert{} = Alert ->
Alert
end.
+%%--------------------------------------------------------------------
+-spec decipher_aead(ssl_cipher:cipher_enum(), #cipher_state{},
+ binary(), binary(), ssl_record:ssl_version()) ->
+ {binary(), #cipher_state{}} | #alert{}.
+%%
+%% Description: Decrypts the data and checks the associated data (AAD) MAC using
+%% cipher described by cipher_enum() and updating the cipher state.
+%% Use for suites that use authenticated encryption with associated data (AEAD)
+%%-------------------------------------------------------------------
+decipher_aead(Type, #cipher_state{key = Key} = CipherState, AAD0, CipherFragment, _) ->
+ try
+ Nonce = decrypt_nonce(Type, CipherState, CipherFragment),
+ {AAD, CipherText, CipherTag} = aead_ciphertext_split(Type, 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.
+
+nonce_seed(?CHACHA20_POLY1305, Seed, CipherState) ->
+ ssl_cipher:nonce_seed(Seed, CipherState);
+nonce_seed(_,_, CipherState) ->
+ CipherState.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
+
empty_connection_state(ConnectionEnd, BeastMitigation) ->
SecParams = empty_security_params(ConnectionEnd),
#{security_parameters => SecParams,
@@ -400,3 +427,37 @@ initial_security_params(ConnectionEnd) ->
compression_algorithm = ?NULL},
ssl_cipher:security_parameters(?TLS_NULL_WITH_NULL_NULL, SecParams).
+cipher_aead(?CHACHA20_POLY1305 = Type, #cipher_state{key=Key} = CipherState, AAD0, Fragment, _Version) ->
+ AAD = end_additional_data(AAD0, erlang:iolist_size(Fragment)),
+ Nonce = encrypt_nonce(Type, CipherState),
+ {Content, CipherTag} = ssl_cipher:aead_encrypt(Type, Key, Nonce, Fragment, AAD),
+ {<<Content/binary, CipherTag/binary>>, CipherState};
+cipher_aead(Type, #cipher_state{key=Key, nonce = ExplicitNonce} = CipherState, AAD0, Fragment, _Version) ->
+ AAD = end_additional_data(AAD0, erlang:iolist_size(Fragment)),
+ Nonce = encrypt_nonce(Type, CipherState),
+ {Content, CipherTag} = ssl_cipher:aead_encrypt(Type, Key, Nonce, Fragment, AAD),
+ {<<ExplicitNonce:64/integer, Content/binary, CipherTag/binary>>, CipherState#cipher_state{nonce = ExplicitNonce + 1}}.
+
+encrypt_nonce(?CHACHA20_POLY1305, #cipher_state{nonce = Nonce, iv = IV}) ->
+ crypto:exor(<<?UINT32(0), Nonce/binary>>, IV);
+encrypt_nonce(?AES_GCM, #cipher_state{iv = IV, nonce = ExplicitNonce}) ->
+ <<Salt:4/bytes, _/binary>> = IV,
+ <<Salt/binary, ExplicitNonce:64/integer>>.
+
+decrypt_nonce(?CHACHA20_POLY1305, #cipher_state{nonce = Nonce, iv = IV}, _) ->
+ crypto:exor(<<Nonce:96/unsigned-big-integer>>, IV);
+decrypt_nonce(?AES_GCM, #cipher_state{iv = <<Salt:4/bytes, _/binary>>}, <<ExplicitNonce:8/bytes, _/binary>>) ->
+ <<Salt/binary, ExplicitNonce/binary>>.
+
+aead_ciphertext_split(?CHACHA20_POLY1305, #cipher_state{tag_len = Len}, CipherTextFragment, AAD) ->
+ CipherLen = size(CipherTextFragment) - Len,
+ <<CipherText:CipherLen/bytes, CipherTag:Len/bytes>> = CipherTextFragment,
+ {end_additional_data(AAD, Len), CipherText, CipherTag};
+aead_ciphertext_split(?AES_GCM, #cipher_state{tag_len = Len}, CipherTextFragment, AAD) ->
+ CipherLen = size(CipherTextFragment) - (Len + 8), %% 8 is length of explicit Nonce
+ << _:8/bytes, CipherText:CipherLen/bytes, CipherTag:Len/bytes>> = CipherTextFragment,
+ {end_additional_data(AAD, CipherLen), CipherText, CipherTag}.
+
+end_additional_data(AAD, Len) ->
+ <<AAD/binary, ?UINT16(Len)>>.
+
diff --git a/lib/ssl/src/tls_record.erl b/lib/ssl/src/tls_record.erl
index f1aca8c801..ce7edc9dcd 100644
--- a/lib/ssl/src/tls_record.erl
+++ b/lib/ssl/src/tls_record.erl
@@ -176,14 +176,15 @@ decode_cipher_text(#ssl_tls{type = Type, version = Version,
BulkCipherAlgo,
compression_algorithm = CompAlg}
} = ReadState0} = ConnnectionStates0, _) ->
- AAD = calc_aad(Type, Version, ReadState0),
- case ssl_cipher:decipher_aead(BulkCipherAlgo, CipherS0, Seq, AAD, CipherFragment, Version) of
- {PlainFragment, CipherS1} ->
+ AAD = start_additional_data(Type, Version, ReadState0),
+ CipherS1 = ssl_record:nonce_seed(BulkCipherAlgo, <<?UINT64(Seq)>>, CipherS0),
+ case ssl_record:decipher_aead(BulkCipherAlgo, CipherS1, AAD, CipherFragment, Version) of
+ {PlainFragment, CipherState} ->
{Plain, CompressionS1} = ssl_record:uncompress(CompAlg,
PlainFragment, CompressionS0),
ConnnectionStates = ConnnectionStates0#{
current_read => ReadState0#{
- cipher_state => CipherS1,
+ cipher_state => CipherState,
sequence_number => Seq + 1,
compression_state => CompressionS1}},
{CipherText#ssl_tls{fragment = Plain}, ConnnectionStates};
@@ -453,15 +454,20 @@ encode_iolist(Type, Data, Version, ConnectionStates0) ->
{lists:reverse(EncodedMsg), ConnectionStates}.
%%--------------------------------------------------------------------
do_encode_plain_text(Type, Version, Data, #{compression_state := CompS0,
- security_parameters :=
+ cipher_state := CipherS0,
+ sequence_number := Seq,
+ security_parameters :=
#security_parameters{
cipher_type = ?AEAD,
+ bulk_cipher_algorithm = BCAlg,
compression_algorithm = CompAlg}
} = WriteState0) ->
{Comp, CompS1} = ssl_record:compress(CompAlg, Data, CompS0),
- WriteState1 = WriteState0#{compression_state => CompS1},
- AAD = calc_aad(Type, Version, WriteState1),
- ssl_record:cipher_aead(Version, Comp, WriteState1, AAD);
+ CipherS = ssl_record:nonce_seed(BCAlg, <<?UINT64(Seq)>>, CipherS0),
+ WriteState = WriteState0#{compression_state => CompS1,
+ cipher_state => CipherS},
+ AAD = start_additional_data(Type, Version, WriteState),
+ ssl_record:cipher_aead(Version, Comp, WriteState, AAD);
do_encode_plain_text(Type, Version, Data, #{compression_state := CompS0,
security_parameters :=
#security_parameters{compression_algorithm = CompAlg}
@@ -473,7 +479,7 @@ do_encode_plain_text(Type, Version, Data, #{compression_state := CompS0,
do_encode_plain_text(_,_,_,CS) ->
exit({cs, CS}).
%%--------------------------------------------------------------------
-calc_aad(Type, {MajVer, MinVer},
+start_additional_data(Type, {MajVer, MinVer},
#{sequence_number := SeqNo}) ->
<<?UINT64(SeqNo), ?BYTE(Type), ?BYTE(MajVer), ?BYTE(MinVer)>>.