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| author | armfazh <armfazh@gmail.com> | 2018-10-19 08:26:58 +1000 |
|---|---|---|
| committer | Pauli <paul.dale@oracle.com> | 2018-10-19 08:26:58 +1000 |
| commit | cb8164b05e3bad5586c2a109bbdbab1ad65a1a6f (patch) | |
| tree | e991589a84fed3cf61db71115d2ff80780b3a65e /ssl/s3_cbc.c | |
| parent | dc5831da59e9bfad61ba425d886a0b06ac160cd6 (diff) | |
| download | openssl-new-cb8164b05e3bad5586c2a109bbdbab1ad65a1a6f.tar.gz | |
Fix tls_cbc_digest_record is slow using SHA-384 and short messages
The formula used for this is now
kVarianceBlocks = ((255 + 1 + md_size + md_block_size - 1) / md_block_size) + 1
Notice that md_block_size=64 for SHA256, which results on the
magic constant kVarianceBlocks = 6.
However, md_block_size=128 for SHA384 leading to kVarianceBlocks = 4.
CLA:trivial
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7342)
Diffstat (limited to 'ssl/s3_cbc.c')
| -rw-r--r-- | ssl/s3_cbc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/ssl/s3_cbc.c b/ssl/s3_cbc.c index 7d9c377697..8e11864b07 100644 --- a/ssl/s3_cbc.c +++ b/ssl/s3_cbc.c @@ -256,12 +256,13 @@ int ssl3_cbc_digest_record(const EVP_MD_CTX *ctx, * of hash termination (0x80 + 64-bit length) don't fit in the final * block, we say that the final two blocks can vary based on the padding. * TLSv1 has MACs up to 48 bytes long (SHA-384) and the padding is not - * required to be minimal. Therefore we say that the final six blocks can + * required to be minimal. Therefore we say that the final |variance_blocks| + * blocks can * vary based on the padding. Later in the function, if the message is * short and there obviously cannot be this many blocks then * variance_blocks can be reduced. */ - variance_blocks = is_sslv3 ? 2 : 6; + variance_blocks = is_sslv3 ? 2 : ( ((255 + 1 + md_size + md_block_size - 1) / md_block_size) + 1); /* * From now on we're dealing with the MAC, which conceptually has 13 * bytes of `header' before the start of the data (TLS) or 71/75 bytes |