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authorRaimo Niskanen <[email protected]>2019-01-23 11:13:52 +0100
committerRaimo Niskanen <[email protected]>2019-02-13 14:03:17 +0100
commit0cc1e1c31ce6bec1bb679628ee1e4e7a095dfba6 (patch)
treeb8e67a111c0688be42df447e83cd2501a70724dd /lib/ssl
parentadb26a65ff5b1f40c3efb96b23c18b2f14839a5a (diff)
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Optimize padding
Diffstat (limited to 'lib/ssl')
-rw-r--r--lib/ssl/src/ssl_cipher.erl61
1 files changed, 45 insertions, 16 deletions
diff --git a/lib/ssl/src/ssl_cipher.erl b/lib/ssl/src/ssl_cipher.erl
index 2c341635a3..ab82b487b9 100644
--- a/lib/ssl/src/ssl_cipher.erl
+++ b/lib/ssl/src/ssl_cipher.erl
@@ -146,8 +146,7 @@ aead_type(?CHACHA20_POLY1305) ->
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].
+ [Fragment, Mac, padding_with_len(TotSz, BlockSz)].
block_cipher(Fun, BlockSz, #cipher_state{key=Key, iv=IV} = CS0,
Mac, Fragment, {3, N})
@@ -723,7 +722,6 @@ expanded_key_material(Cipher) when Cipher == aes_128_cbc;
Cipher == chacha20_poly1305 ->
unknown.
-
effective_key_bits(null) ->
0;
effective_key_bits(des_cbc) ->
@@ -743,18 +741,15 @@ iv_size(Cipher) when Cipher == null;
Cipher == rc4_128;
Cipher == chacha20_poly1305->
0;
-
iv_size(Cipher) when Cipher == aes_128_gcm;
Cipher == aes_256_gcm ->
4;
-
iv_size(Cipher) ->
block_size(Cipher).
block_size(Cipher) when Cipher == des_cbc;
Cipher == '3des_ede_cbc' ->
8;
-
block_size(Cipher) when Cipher == aes_128_cbc;
Cipher == aes_256_cbc;
Cipher == aes_128_gcm;
@@ -889,17 +884,51 @@ is_correct_padding(GenBlockCipher, {3, 1}, false) ->
%% Padding must be checked in TLS 1.1 and after
is_correct_padding(#generic_block_cipher{padding_length = Len,
padding = Padding}, _, _) ->
- Len == byte_size(Padding) andalso
- binary:copy(?byte(Len), Len) == Padding.
-
-get_padding(Length, BlockSize) ->
- get_padding_aux(BlockSize, Length rem BlockSize).
+ (Len == byte_size(Padding)) andalso (padding(Len) == Padding).
+
+padding(PadLen) ->
+ case PadLen of
+ 0 -> <<>>;
+ 1 -> <<1>>;
+ 2 -> <<2,2>>;
+ 3 -> <<3,3,3>>;
+ 4 -> <<4,4,4,4>>;
+ 5 -> <<5,5,5,5,5>>;
+ 6 -> <<6,6,6,6,6,6>>;
+ 7 -> <<7,7,7,7,7,7,7>>;
+ 8 -> <<8,8,8,8,8,8,8,8>>;
+ 9 -> <<9,9,9,9,9,9,9,9,9>>;
+ 10 -> <<10,10,10,10,10,10,10,10,10,10>>;
+ 11 -> <<11,11,11,11,11,11,11,11,11,11,11>>;
+ 12 -> <<12,12,12,12,12,12,12,12,12,12,12,12>>;
+ 13 -> <<13,13,13,13,13,13,13,13,13,13,13,13,13>>;
+ 14 -> <<14,14,14,14,14,14,14,14,14,14,14,14,14,14>>;
+ 15 -> <<15,15,15,15,15,15,15,15,15,15,15,15,15,15,15>>;
+ _ ->
+ binary:copy(<<PadLen>>, PadLen)
+ end.
-get_padding_aux(_, 0) ->
- {0, <<>>};
-get_padding_aux(BlockSize, PadLength) ->
- N = BlockSize - PadLength,
- {N, binary:copy(?byte(N), N)}.
+padding_with_len(TextLen, BlockSize) ->
+ case BlockSize - (TextLen rem BlockSize) of
+ 0 -> <<0>>;
+ 1 -> <<1,1>>;
+ 2 -> <<2,2,2>>;
+ 3 -> <<3,3,3,3>>;
+ 4 -> <<4,4,4,4,4>>;
+ 5 -> <<5,5,5,5,5,5>>;
+ 6 -> <<6,6,6,6,6,6,6>>;
+ 7 -> <<7,7,7,7,7,7,7,7>>;
+ 8 -> <<8,8,8,8,8,8,8,8,8>>;
+ 9 -> <<9,9,9,9,9,9,9,9,9,9>>;
+ 10 -> <<10,10,10,10,10,10,10,10,10,10,10>>;
+ 11 -> <<11,11,11,11,11,11,11,11,11,11,11,11>>;
+ 12 -> <<12,12,12,12,12,12,12,12,12,12,12,12,12>>;
+ 13 -> <<13,13,13,13,13,13,13,13,13,13,13,13,13,13>>;
+ 14 -> <<14,14,14,14,14,14,14,14,14,14,14,14,14,14,14>>;
+ 15 -> <<15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15>>;
+ PadLen ->
+ binary:copy(<<PadLen>>, PadLen + 1)
+ end.
random_iv(IV) ->
IVSz = byte_size(IV),