%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2007-2011. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
%%----------------------------------------------------------------------
%% Purpose: Help functions for handling the SSL ciphers
%%
%%----------------------------------------------------------------------
-module(ssl_cipher).
-include("ssl_internal.hrl").
-include("ssl_record.hrl").
-include("ssl_cipher.hrl").
-include("ssl_alert.hrl").
-include_lib("public_key/include/public_key.hrl").
-export([security_parameters/2, suite_definition/1,
decipher/5, cipher/5,
suite/1, suites/1, anonymous_suites/0,
openssl_suite/1, openssl_suite_name/1, filter/2]).
-compile(inline).
%%--------------------------------------------------------------------
-spec security_parameters(cipher_suite(), #security_parameters{}) ->
#security_parameters{}.
%%
%% Description: Returns a security parameters record where the
%% cipher values has been updated according to <CipherSuite>
%%-------------------------------------------------------------------
security_parameters(CipherSuite, SecParams) ->
{ _, Cipher, Hash} = suite_definition(CipherSuite),
SecParams#security_parameters{
cipher_suite = CipherSuite,
bulk_cipher_algorithm = bulk_cipher_algorithm(Cipher),
cipher_type = type(Cipher),
key_size = effective_key_bits(Cipher),
expanded_key_material_length = expanded_key_material(Cipher),
key_material_length = key_material(Cipher),
iv_size = iv_size(Cipher),
mac_algorithm = mac_algorithm(Hash),
hash_size = hash_size(Hash)}.
%%--------------------------------------------------------------------
-spec cipher(cipher_enum(), #cipher_state{}, binary(), binary(), tls_version()) ->
{binary(), #cipher_state{}}.
%%
%% Description: Encrypts the data and the MAC using chipher described
%% by cipher_enum() and updating the cipher state
%%-------------------------------------------------------------------
cipher(?NULL, CipherState, <<>>, Fragment, _Version) ->
GenStreamCipherList = [Fragment, <<>>],
{GenStreamCipherList, CipherState};
cipher(?RC4, CipherState, Mac, Fragment, _Version) ->
State0 = case CipherState#cipher_state.state of
undefined -> crypto:rc4_set_key(CipherState#cipher_state.key);
S -> S
end,
GenStreamCipherList = [Fragment, Mac],
{State1, T} = crypto:rc4_encrypt_with_state(State0, GenStreamCipherList),
{T, CipherState#cipher_state{state = State1}};
cipher(?DES, CipherState, Mac, Fragment, Version) ->
block_cipher(fun(Key, IV, T) ->
crypto:des_cbc_encrypt(Key, IV, T)
end, block_size(des_cbc), CipherState, Mac, Fragment, Version);
cipher(?'3DES', CipherState, Mac, Fragment, Version) ->
block_cipher(fun(<<K1:8/binary, K2:8/binary, K3:8/binary>>, IV, T) ->
crypto:des3_cbc_encrypt(K1, K2, K3, IV, T)
end, block_size(des_cbc), CipherState, Mac, Fragment, Version);
cipher(?AES, CipherState, Mac, Fragment, Version) ->
block_cipher(fun(Key, IV, T) when byte_size(Key) =:= 16 ->
crypto:aes_cbc_128_encrypt(Key, IV, T);
(Key, IV, T) when byte_size(Key) =:= 32 ->
crypto:aes_cbc_256_encrypt(Key, IV, T)
end, block_size(aes_128_cbc), CipherState, Mac, Fragment, Version).
%% cipher(?IDEA, CipherState, Mac, Fragment) ->
%% block_cipher(fun(Key, IV, T) ->
%% crypto:idea_cbc_encrypt(Key, IV, T)
%% end, block_size(idea_cbc), CipherState, Mac, Fragment);
build_cipher_block(BlockSz, Mac, Fragment) ->
TotSz = byte_size(Mac) + erlang:iolist_size(Fragment) + 1,
{PaddingLength, Padding} = get_padding(TotSz, BlockSz),
[Fragment, Mac, PaddingLength, Padding].
block_cipher(Fun, BlockSz, #cipher_state{key=Key, iv=IV} = CS0,
Mac, Fragment, {3, N})
when N == 0; N == 1 ->
L = build_cipher_block(BlockSz, Mac, Fragment),
T = Fun(Key, IV, L),
NextIV = next_iv(T, IV),
{T, CS0#cipher_state{iv=NextIV}}.
%%--------------------------------------------------------------------
-spec decipher(cipher_enum(), integer(), #cipher_state{}, binary(), tls_version()) ->
{binary(), binary(), #cipher_state{}} | #alert{}.
%%
%% Description: Decrypts the data and the MAC using cipher described
%% by cipher_enum() and updating the cipher state.
%%-------------------------------------------------------------------
decipher(?NULL, _HashSz, CipherState, Fragment, _) ->
{Fragment, <<>>, CipherState};
decipher(?RC4, HashSz, CipherState, Fragment, _) ->
State0 = case CipherState#cipher_state.state of
undefined -> crypto:rc4_set_key(CipherState#cipher_state.key);
S -> S
end,
try crypto:rc4_encrypt_with_state(State0, Fragment) of
{State, Text} ->
GSC = generic_stream_cipher_from_bin(Text, HashSz),
#generic_stream_cipher{content = Content, mac = Mac} = GSC,
{Content, Mac, CipherState#cipher_state{state = State}}
catch
_:_ ->
%% This is a DECRYPTION_FAILED but
%% "differentiating between bad_record_mac and decryption_failed
%% alerts may permit certain attacks against CBC mode as used in
%% TLS [CBCATT]. It is preferable to uniformly use the
%% bad_record_mac alert to hide the specific type of the error."
?ALERT_REC(?FATAL, ?BAD_RECORD_MAC)
end;
decipher(?DES, HashSz, CipherState, Fragment, Version) ->
block_decipher(fun(Key, IV, T) ->
crypto:des_cbc_decrypt(Key, IV, T)
end, CipherState, HashSz, Fragment, Version);
decipher(?'3DES', HashSz, CipherState, Fragment, Version) ->
block_decipher(fun(<<K1:8/binary, K2:8/binary, K3:8/binary>>, IV, T) ->
crypto:des3_cbc_decrypt(K1, K2, K3, IV, T)
end, CipherState, HashSz, Fragment, Version);
decipher(?AES, HashSz, CipherState, Fragment, Version) ->
block_decipher(fun(Key, IV, T) when byte_size(Key) =:= 16 ->
crypto:aes_cbc_128_decrypt(Key, IV, T);
(Key, IV, T) when byte_size(Key) =:= 32 ->
crypto:aes_cbc_256_decrypt(Key, IV, T)
end, CipherState, HashSz, Fragment, Version).
%% decipher(?IDEA, HashSz, CipherState, Fragment, Version) ->
%% block_decipher(fun(Key, IV, T) ->
%% crypto:idea_cbc_decrypt(Key, IV, T)
%% end, CipherState, HashSz, Fragment, Version);
block_decipher(Fun, #cipher_state{key=Key, iv=IV} = CipherState0,
HashSz, Fragment, Version) ->
try
Text = Fun(Key, IV, Fragment),
NextIV = next_iv(Fragment, IV),
GBC = generic_block_cipher_from_bin(Version, Text, NextIV, HashSz),
Content = GBC#generic_block_cipher.content,
Mac = GBC#generic_block_cipher.mac,
CipherState1 = CipherState0#cipher_state{iv=GBC#generic_block_cipher.next_iv},
case is_correct_padding(GBC, Version) of
true ->
{Content, Mac, CipherState1};
false ->
%% decryption failed or invalid padding,
%% intentionally break Content to make
%% sure a packet with invalid padding
%% but otherwise correct data will fail
%% the MAC test later
{<<16#F0, Content/binary>>, Mac, CipherState1}
end
catch
_:_ ->
%% This is a DECRYPTION_FAILED but
%% "differentiating between bad_record_mac and decryption_failed
%% alerts may permit certain attacks against CBC mode as used in
%% TLS [CBCATT]. It is preferable to uniformly use the
%% bad_record_mac alert to hide the specific type of the error."
?ALERT_REC(?FATAL, ?BAD_RECORD_MAC)
end.
%%--------------------------------------------------------------------
-spec suites(tls_version()) -> [cipher_suite()].
%%
%% Description: Returns a list of supported cipher suites.
%%--------------------------------------------------------------------
suites({3, 0}) ->
ssl_ssl3:suites();
suites({3, N}) when N == 1; N == 2 ->
ssl_tls1:suites().
%%--------------------------------------------------------------------
-spec anonymous_suites() -> [cipher_suite()].
%%
%% Description: Returns a list of the anonymous cipher suites, only supported
%% if explicitly set by user. Intended only for testing.
%%--------------------------------------------------------------------
anonymous_suites() ->
[?TLS_DH_anon_WITH_RC4_128_MD5,
?TLS_DH_anon_WITH_DES_CBC_SHA,
?TLS_DH_anon_WITH_3DES_EDE_CBC_SHA,
?TLS_DH_anon_WITH_AES_128_CBC_SHA,
?TLS_DH_anon_WITH_AES_256_CBC_SHA].
%%--------------------------------------------------------------------
-spec suite_definition(cipher_suite()) -> erl_cipher_suite().
%%
%% Description: Return erlang cipher suite definition.
%% Note: Currently not supported suites are commented away.
%% They should be supported or removed in the future.
%%-------------------------------------------------------------------
%% TLS v1.1 suites
suite_definition(?TLS_NULL_WITH_NULL_NULL) ->
{null, null, null};
%% suite_definition(?TLS_RSA_WITH_NULL_MD5) ->
%% {rsa, null, md5};
%% suite_definition(?TLS_RSA_WITH_NULL_SHA) ->
%% {rsa, null, sha};
suite_definition(?TLS_RSA_WITH_RC4_128_MD5) ->
{rsa, rc4_128, md5};
suite_definition(?TLS_RSA_WITH_RC4_128_SHA) ->
{rsa, rc4_128, sha};
%% suite_definition(?TLS_RSA_WITH_IDEA_CBC_SHA) ->
%% {rsa, idea_cbc, sha};
suite_definition(?TLS_RSA_WITH_DES_CBC_SHA) ->
{rsa, des_cbc, sha};
suite_definition(?TLS_RSA_WITH_3DES_EDE_CBC_SHA) ->
{rsa, '3des_ede_cbc', sha};
suite_definition(?TLS_DHE_DSS_WITH_DES_CBC_SHA) ->
{dhe_dss, des_cbc, sha};
suite_definition(?TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA) ->
{dhe_dss, '3des_ede_cbc', sha};
suite_definition(?TLS_DHE_RSA_WITH_DES_CBC_SHA) ->
{dhe_rsa, des_cbc, sha};
suite_definition(?TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA) ->
{dhe_rsa, '3des_ede_cbc', sha};
%%% TSL V1.1 AES suites
suite_definition(?TLS_RSA_WITH_AES_128_CBC_SHA) ->
{rsa, aes_128_cbc, sha};
suite_definition(?TLS_DHE_DSS_WITH_AES_128_CBC_SHA) ->
{dhe_dss, aes_128_cbc, sha};
suite_definition(?TLS_DHE_RSA_WITH_AES_128_CBC_SHA) ->
{dhe_rsa, aes_128_cbc, sha};
suite_definition(?TLS_RSA_WITH_AES_256_CBC_SHA) ->
{rsa, aes_256_cbc, sha};
suite_definition(?TLS_DHE_DSS_WITH_AES_256_CBC_SHA) ->
{dhe_dss, aes_256_cbc, sha};
suite_definition(?TLS_DHE_RSA_WITH_AES_256_CBC_SHA) ->
{dhe_rsa, aes_256_cbc, sha};
%%% DH-ANON deprecated by TLS spec and not available
%%% by default, but good for testing purposes.
suite_definition(?TLS_DH_anon_WITH_RC4_128_MD5) ->
{dh_anon, rc4_128, md5};
suite_definition(?TLS_DH_anon_WITH_DES_CBC_SHA) ->
{dh_anon, des_cbc, sha};
suite_definition(?TLS_DH_anon_WITH_3DES_EDE_CBC_SHA) ->
{dh_anon, '3des_ede_cbc', sha};
suite_definition(?TLS_DH_anon_WITH_AES_128_CBC_SHA) ->
{dh_anon, aes_128_cbc, sha};
suite_definition(?TLS_DH_anon_WITH_AES_256_CBC_SHA) ->
{dh_anon, aes_256_cbc, sha}.
%%--------------------------------------------------------------------
-spec suite(erl_cipher_suite()) -> cipher_suite().
%%
%% Description: Return TLS cipher suite definition.
%%--------------------------------------------------------------------
%% TLS v1.1 suites
%%suite({rsa, null, md5}) ->
%% ?TLS_RSA_WITH_NULL_MD5;
%%suite({rsa, null, sha}) ->
%% ?TLS_RSA_WITH_NULL_SHA;
suite({rsa, rc4_128, md5}) ->
?TLS_RSA_WITH_RC4_128_MD5;
suite({rsa, rc4_128, sha}) ->
?TLS_RSA_WITH_RC4_128_SHA;
%% suite({rsa, idea_cbc, sha}) ->
%% ?TLS_RSA_WITH_IDEA_CBC_SHA;
suite({rsa, des_cbc, sha}) ->
?TLS_RSA_WITH_DES_CBC_SHA;
suite({rsa, '3des_ede_cbc', sha}) ->
?TLS_RSA_WITH_3DES_EDE_CBC_SHA;
suite({dhe_dss, des_cbc, sha}) ->
?TLS_DHE_DSS_WITH_DES_CBC_SHA;
suite({dhe_dss, '3des_ede_cbc', sha}) ->
?TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA;
suite({dhe_rsa, des_cbc, sha}) ->
?TLS_DHE_RSA_WITH_DES_CBC_SHA;
suite({dhe_rsa, '3des_ede_cbc', sha}) ->
?TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA;
suite({dh_anon, rc4_128, md5}) ->
?TLS_DH_anon_WITH_RC4_128_MD5;
suite({dh_anon, des_cbc, sha}) ->
?TLS_DH_anon_WITH_DES_CBC_SHA;
suite({dh_anon, '3des_ede_cbc', sha}) ->
?TLS_DH_anon_WITH_3DES_EDE_CBC_SHA;
%%% TSL V1.1 AES suites
suite({rsa, aes_128_cbc, sha}) ->
?TLS_RSA_WITH_AES_128_CBC_SHA;
suite({dhe_dss, aes_128_cbc, sha}) ->
?TLS_DHE_DSS_WITH_AES_128_CBC_SHA;
suite({dhe_rsa, aes_128_cbc, sha}) ->
?TLS_DHE_RSA_WITH_AES_128_CBC_SHA;
suite({dh_anon, aes_128_cbc, sha}) ->
?TLS_DH_anon_WITH_AES_128_CBC_SHA;
suite({rsa, aes_256_cbc, sha}) ->
?TLS_RSA_WITH_AES_256_CBC_SHA;
suite({dhe_dss, aes_256_cbc, sha}) ->
?TLS_DHE_DSS_WITH_AES_256_CBC_SHA;
suite({dhe_rsa, aes_256_cbc, sha}) ->
?TLS_DHE_RSA_WITH_AES_256_CBC_SHA;
suite({dh_anon, aes_256_cbc, sha}) ->
?TLS_DH_anon_WITH_AES_256_CBC_SHA.
%%--------------------------------------------------------------------
-spec openssl_suite(openssl_cipher_suite()) -> cipher_suite().
%%
%% Description: Return TLS cipher suite definition.
%%--------------------------------------------------------------------
%% translate constants <-> openssl-strings
openssl_suite("DHE-RSA-AES256-SHA") ->
?TLS_DHE_RSA_WITH_AES_256_CBC_SHA;
openssl_suite("DHE-DSS-AES256-SHA") ->
?TLS_DHE_DSS_WITH_AES_256_CBC_SHA;
openssl_suite("AES256-SHA") ->
?TLS_RSA_WITH_AES_256_CBC_SHA;
openssl_suite("EDH-RSA-DES-CBC3-SHA") ->
?TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA;
openssl_suite("EDH-DSS-DES-CBC3-SHA") ->
?TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA;
openssl_suite("DES-CBC3-SHA") ->
?TLS_RSA_WITH_3DES_EDE_CBC_SHA;
openssl_suite("DHE-RSA-AES128-SHA") ->
?TLS_DHE_RSA_WITH_AES_128_CBC_SHA;
openssl_suite("DHE-DSS-AES128-SHA") ->
?TLS_DHE_DSS_WITH_AES_128_CBC_SHA;
openssl_suite("AES128-SHA") ->
?TLS_RSA_WITH_AES_128_CBC_SHA;
%%openssl_suite("IDEA-CBC-SHA") ->
%% ?TLS_RSA_WITH_IDEA_CBC_SHA;
openssl_suite("RC4-SHA") ->
?TLS_RSA_WITH_RC4_128_SHA;
openssl_suite("RC4-MD5") ->
?TLS_RSA_WITH_RC4_128_MD5;
openssl_suite("EDH-RSA-DES-CBC-SHA") ->
?TLS_DHE_RSA_WITH_DES_CBC_SHA;
openssl_suite("DES-CBC-SHA") ->
?TLS_RSA_WITH_DES_CBC_SHA.
%%--------------------------------------------------------------------
-spec openssl_suite_name(cipher_suite()) -> openssl_cipher_suite().
%%
%% Description: Return openssl cipher suite name.
%%-------------------------------------------------------------------
openssl_suite_name(?TLS_DHE_RSA_WITH_AES_256_CBC_SHA) ->
"DHE-RSA-AES256-SHA";
openssl_suite_name(?TLS_DHE_DSS_WITH_AES_256_CBC_SHA) ->
"DHE-DSS-AES256-SHA";
openssl_suite_name(?TLS_RSA_WITH_AES_256_CBC_SHA) ->
"AES256-SHA";
openssl_suite_name(?TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA) ->
"EDH-RSA-DES-CBC3-SHA";
openssl_suite_name(?TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA) ->
"EDH-DSS-DES-CBC3-SHA";
openssl_suite_name(?TLS_RSA_WITH_3DES_EDE_CBC_SHA) ->
"DES-CBC3-SHA";
openssl_suite_name( ?TLS_DHE_RSA_WITH_AES_128_CBC_SHA) ->
"DHE-RSA-AES128-SHA";
openssl_suite_name(?TLS_DHE_DSS_WITH_AES_128_CBC_SHA) ->
"DHE-DSS-AES128-SHA";
openssl_suite_name(?TLS_RSA_WITH_AES_128_CBC_SHA) ->
"AES128-SHA";
%% openssl_suite_name(?TLS_RSA_WITH_IDEA_CBC_SHA) ->
%% "IDEA-CBC-SHA";
openssl_suite_name(?TLS_RSA_WITH_RC4_128_SHA) ->
"RC4-SHA";
openssl_suite_name(?TLS_RSA_WITH_RC4_128_MD5) ->
"RC4-MD5";
openssl_suite_name(?TLS_DHE_RSA_WITH_DES_CBC_SHA) ->
"EDH-RSA-DES-CBC-SHA";
openssl_suite_name(?TLS_RSA_WITH_DES_CBC_SHA) ->
"DES-CBC-SHA";
%% No oppenssl name
openssl_suite_name(Cipher) ->
suite_definition(Cipher).
%%--------------------------------------------------------------------
-spec filter(undefined | binary(), [cipher_suite()]) -> [cipher_suite()].
%%
%% Description: .
%%-------------------------------------------------------------------
filter(undefined, Ciphers) ->
Ciphers;
filter(DerCert, Ciphers) ->
OtpCert = public_key:pkix_decode_cert(DerCert, otp),
SigAlg = OtpCert#'OTPCertificate'.signatureAlgorithm,
case ssl_certificate:signature_type(SigAlg#'SignatureAlgorithm'.algorithm) of
rsa ->
filter_rsa(OtpCert, Ciphers -- dsa_signed_suites());
dsa ->
Ciphers -- rsa_signed_suites()
end.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
bulk_cipher_algorithm(null) ->
?NULL;
%% Not supported yet
%% bulk_cipher_algorithm(idea_cbc) ->
%% ?IDEA;
bulk_cipher_algorithm(rc4_128) ->
?RC4;
bulk_cipher_algorithm(des_cbc) ->
?DES;
bulk_cipher_algorithm('3des_ede_cbc') ->
?'3DES';
bulk_cipher_algorithm(Cipher) when Cipher == aes_128_cbc;
Cipher == aes_256_cbc ->
?AES.
type(Cipher) when Cipher == null;
Cipher == rc4_128 ->
?STREAM;
type(Cipher) when Cipher == idea_cbc;
Cipher == des_cbc;
Cipher == '3des_ede_cbc';
Cipher == aes_128_cbc;
Cipher == aes_256_cbc ->
?BLOCK.
key_material(null) ->
0;
key_material(Cipher) when Cipher == idea_cbc;
Cipher == rc4_128 ->
16;
key_material(des_cbc) ->
8;
key_material('3des_ede_cbc') ->
24;
key_material(aes_128_cbc) ->
16;
key_material(aes_256_cbc) ->
32.
expanded_key_material(null) ->
0;
expanded_key_material(Cipher) when Cipher == idea_cbc;
Cipher == rc4_128 ->
16;
expanded_key_material(Cipher) when Cipher == des_cbc ->
8;
expanded_key_material('3des_ede_cbc') ->
24;
expanded_key_material(Cipher) when Cipher == aes_128_cbc;
Cipher == aes_256_cbc ->
unknown.
effective_key_bits(null) ->
0;
effective_key_bits(des_cbc) ->
56;
effective_key_bits(Cipher) when Cipher == idea_cbc;
Cipher == rc4_128;
Cipher == aes_128_cbc ->
128;
effective_key_bits('3des_ede_cbc') ->
168;
effective_key_bits(aes_256_cbc) ->
256.
iv_size(Cipher) when Cipher == null;
Cipher == rc4_128 ->
0;
iv_size(Cipher) ->
block_size(Cipher).
block_size(Cipher) when Cipher == idea_cbc;
Cipher == des_cbc;
Cipher == '3des_ede_cbc' ->
8;
block_size(Cipher) when Cipher == aes_128_cbc;
Cipher == aes_256_cbc ->
16.
mac_algorithm(null) ->
?NULL;
mac_algorithm(md5) ->
?MD5;
mac_algorithm(sha) ->
?SHA.
hash_size(null) ->
0;
hash_size(md5) ->
16;
hash_size(sha) ->
20.
%% RFC 5246: 6.2.3.2. CBC Block Cipher
%%
%% Implementation note: Canvel et al. [CBCTIME] have demonstrated a
%% timing attack on CBC padding based on the time required to compute
%% the MAC. In order to defend against this attack, implementations
%% MUST ensure that record processing time is essentially the same
%% whether or not the padding is correct. In general, the best way to
%% do this is to compute the MAC even if the padding is incorrect, and
%% only then reject the packet. For instance, if the pad appears to be
%% incorrect, the implementation might assume a zero-length pad and then
%% compute the MAC. This leaves a small timing channel, since MAC
%% performance depends to some extent on the size of the data fragment,
%% but it is not believed to be large enough to be exploitable, due to
%% the large block size of existing MACs and the small size of the
%% timing signal.
%%
%% implementation note:
%% We return the original (possibly invalid) PadLength in any case.
%% An invalid PadLength will be caught by is_correct_padding/2
%%
generic_block_cipher_from_bin({3, N}, T, IV, HashSize)
when N == 0; N == 1 ->
Sz1 = byte_size(T) - 1,
<<_:Sz1/binary, ?BYTE(PadLength0)>> = T,
PadLength = if
PadLength0 >= Sz1 -> 0;
true -> PadLength0
end,
CompressedLength = byte_size(T) - PadLength - 1 - HashSize,
<<Content:CompressedLength/binary, Mac:HashSize/binary,
Padding:PadLength/binary, ?BYTE(PadLength0)>> = T,
#generic_block_cipher{content=Content, mac=Mac,
padding=Padding, padding_length=PadLength0,
next_iv = IV}.
generic_stream_cipher_from_bin(T, HashSz) ->
Sz = byte_size(T),
CompressedLength = Sz - HashSz,
<<Content:CompressedLength/binary, Mac:HashSz/binary>> = T,
#generic_stream_cipher{content=Content,
mac=Mac}.
%% For interoperability reasons we do not check the padding content in
%% SSL 3.0 and TLS 1.0 as it is not strictly required and breaks
%% interopability with for instance Google.
is_correct_padding(#generic_block_cipher{padding_length = Len,
padding = Padding}, {3, N})
when N == 0; N == 1 ->
Len == byte_size(Padding);
%% Padding must be check in TLS 1.1 and after
is_correct_padding(#generic_block_cipher{padding_length = Len,
padding = Padding}, _) ->
Len == byte_size(Padding) andalso
list_to_binary(lists:duplicate(Len, Len)) == Padding.
get_padding(Length, BlockSize) ->
get_padding_aux(BlockSize, Length rem BlockSize).
get_padding_aux(_, 0) ->
{0, <<>>};
get_padding_aux(BlockSize, PadLength) ->
N = BlockSize - PadLength,
{N, list_to_binary(lists:duplicate(N, N))}.
next_iv(Bin, IV) ->
BinSz = byte_size(Bin),
IVSz = byte_size(IV),
FirstPart = BinSz - IVSz,
<<_:FirstPart/binary, NextIV:IVSz/binary>> = Bin,
NextIV.
rsa_signed_suites() ->
dhe_rsa_suites() ++ rsa_suites().
dhe_rsa_suites() ->
[?TLS_DHE_RSA_WITH_AES_256_CBC_SHA,
?TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA,
?TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
?TLS_DHE_RSA_WITH_DES_CBC_SHA].
rsa_suites() ->
[?TLS_RSA_WITH_AES_256_CBC_SHA,
?TLS_RSA_WITH_3DES_EDE_CBC_SHA,
?TLS_RSA_WITH_AES_128_CBC_SHA,
%%?TLS_RSA_WITH_IDEA_CBC_SHA,
?TLS_RSA_WITH_RC4_128_SHA,
?TLS_RSA_WITH_RC4_128_MD5,
?TLS_RSA_WITH_DES_CBC_SHA].
dsa_signed_suites() ->
dhe_dss_suites().
dhe_dss_suites() ->
[?TLS_DHE_DSS_WITH_AES_256_CBC_SHA,
?TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA,
?TLS_DHE_DSS_WITH_AES_128_CBC_SHA,
?TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA].
filter_rsa(OtpCert, RsaCiphers) ->
TBSCert = OtpCert#'OTPCertificate'.tbsCertificate,
TBSExtensions = TBSCert#'OTPTBSCertificate'.extensions,
Extensions = ssl_certificate:extensions_list(TBSExtensions),
case ssl_certificate:select_extension(?'id-ce-keyUsage', Extensions) of
undefined ->
RsaCiphers;
#'Extension'{extnValue = KeyUse} ->
Result = filter_rsa_suites(keyEncipherment,
KeyUse, RsaCiphers, rsa_suites()),
filter_rsa_suites(digitalSignature,
KeyUse, Result, dhe_rsa_suites())
end.
filter_rsa_suites(Use, KeyUse, CipherSuits, RsaSuites) ->
case ssl_certificate:is_valid_key_usage(KeyUse, Use) of
true ->
CipherSuits;
false ->
CipherSuits -- RsaSuites
end.
