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authorIngela Anderton Andin <ingela@erlang.org>2015-01-13 15:16:20 +0100
committerIngela Anderton Andin <ingela@erlang.org>2015-01-23 11:34:18 +0100
commit519b07bca04bdd8585b48f2de6b7124ca6455358 (patch)
tree71dcbdfd4b32ff7784bb91d35f0cc3eecccb0c64 /lib/ssl/src/ssl_cipher.erl
parent69de799fdce1c4cc5a582df6f2a86ccd3e62c3a9 (diff)
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ssl: Reenable padding check for TLS-1.0 and provide backwards compatible
disable option
Diffstat (limited to 'lib/ssl/src/ssl_cipher.erl')
-rw-r--r--lib/ssl/src/ssl_cipher.erl43
1 files changed, 23 insertions, 20 deletions
diff --git a/lib/ssl/src/ssl_cipher.erl b/lib/ssl/src/ssl_cipher.erl
index e1d89c149e..939778dd40 100644
--- a/lib/ssl/src/ssl_cipher.erl
+++ b/lib/ssl/src/ssl_cipher.erl
@@ -33,7 +33,7 @@
-include_lib("public_key/include/public_key.hrl").
-export([security_parameters/2, security_parameters/3, suite_definition/1,
- cipher_init/3, decipher/5, cipher/5, decipher_aead/6, cipher_aead/6,
+ cipher_init/3, decipher/6, cipher/5, decipher_aead/6, cipher_aead/6,
suite/1, suites/1, all_suites/1,
ec_keyed_suites/0, anonymous_suites/1, psk_suites/1, srp_suites/0,
openssl_suite/1, openssl_suite_name/1, filter/2, filter_suites/1,
@@ -182,7 +182,8 @@ block_cipher(Fun, BlockSz, #cipher_state{key=Key, iv=IV} = CS0,
{T, CS0#cipher_state{iv=NextIV}}.
%%--------------------------------------------------------------------
--spec decipher(cipher_enum(), integer(), #cipher_state{}, binary(), ssl_record:ssl_version()) ->
+-spec decipher(cipher_enum(), integer(), #cipher_state{}, binary(),
+ ssl_record:ssl_version(), boolean()) ->
{binary(), binary(), #cipher_state{}} | #alert{}.
%%
%% Description: Decrypts the data and the MAC using cipher described
@@ -190,9 +191,9 @@ block_cipher(Fun, BlockSz, #cipher_state{key=Key, iv=IV} = CS0,
%% Used for "MAC then Cipher" suites where first the data is decrypted
%% and the an HMAC of the decrypted data is checked
%%-------------------------------------------------------------------
-decipher(?NULL, _HashSz, CipherState, Fragment, _) ->
+decipher(?NULL, _HashSz, CipherState, Fragment, _, _) ->
{Fragment, <<>>, CipherState};
-decipher(?RC4, HashSz, CipherState = #cipher_state{state = State0}, Fragment, _) ->
+decipher(?RC4, HashSz, CipherState = #cipher_state{state = State0}, Fragment, _, _) ->
try crypto:stream_decrypt(State0, Fragment) of
{State, Text} ->
GSC = generic_stream_cipher_from_bin(Text, HashSz),
@@ -208,20 +209,20 @@ decipher(?RC4, HashSz, CipherState = #cipher_state{state = State0}, Fragment, _)
?ALERT_REC(?FATAL, ?BAD_RECORD_MAC)
end;
-decipher(?DES, HashSz, CipherState, Fragment, Version) ->
+decipher(?DES, HashSz, CipherState, Fragment, Version, PaddingCheck) ->
block_decipher(fun(Key, IV, T) ->
crypto:block_decrypt(des_cbc, Key, IV, T)
- end, CipherState, HashSz, Fragment, Version);
-decipher(?'3DES', HashSz, CipherState, Fragment, Version) ->
+ end, CipherState, HashSz, Fragment, Version, PaddingCheck);
+decipher(?'3DES', HashSz, CipherState, Fragment, Version, PaddingCheck) ->
block_decipher(fun(<<K1:8/binary, K2:8/binary, K3:8/binary>>, IV, T) ->
crypto:block_decrypt(des3_cbc, [K1, K2, K3], IV, T)
- end, CipherState, HashSz, Fragment, Version);
-decipher(?AES_CBC, HashSz, CipherState, Fragment, Version) ->
+ end, CipherState, HashSz, Fragment, Version, PaddingCheck);
+decipher(?AES_CBC, HashSz, CipherState, Fragment, Version, PaddingCheck) ->
block_decipher(fun(Key, IV, T) when byte_size(Key) =:= 16 ->
crypto:block_decrypt(aes_cbc128, Key, IV, T);
(Key, IV, T) when byte_size(Key) =:= 32 ->
crypto:block_decrypt(aes_cbc256, Key, IV, T)
- end, CipherState, HashSz, Fragment, Version).
+ end, CipherState, HashSz, Fragment, Version, PaddingCheck).
%%--------------------------------------------------------------------
-spec decipher_aead(cipher_enum(), #cipher_state{}, integer(), binary(), binary(), ssl_record:ssl_version()) ->
@@ -237,7 +238,7 @@ 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) ->
+ HashSz, Fragment, Version, PaddingCheck) ->
try
Text = Fun(Key, IV, Fragment),
NextIV = next_iv(Fragment, IV),
@@ -245,7 +246,7 @@ block_decipher(Fun, #cipher_state{key=Key, iv=IV} = CipherState0,
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
+ case is_correct_padding(GBC, Version, PaddingCheck) of
true ->
{Content, Mac, CipherState1};
false ->
@@ -1632,16 +1633,18 @@ generic_stream_cipher_from_bin(T, HashSz) ->
#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
+ padding = Padding}, {3, 0}, _) ->
+ Len == byte_size(Padding); %% Only length check is done in SSL 3.0 spec
+%% For interoperability reasons it is possible to disable
+%% the padding check when using TLS 1.0, as it is not strictly required
+%% in the spec (only recommended), howerver this makes TLS 1.0 vunrable to the Poodle attack
+%% so by default this clause will not match
+is_correct_padding(GenBlockCipher, {3, 1}, false) ->
+ is_correct_padding(GenBlockCipher, {3, 0}, false);
+%% Padding must be checked in TLS 1.1 and after
is_correct_padding(#generic_block_cipher{padding_length = Len,
- padding = Padding}, _) ->
+ padding = Padding}, _, _) ->
Len == byte_size(Padding) andalso
list_to_binary(lists:duplicate(Len, Len)) == Padding.