From 144724c75584054329a9d6bb7711cec527fbf523 Mon Sep 17 00:00:00 2001 From: Viktor Dukhovni Date: Tue, 13 Feb 2018 22:43:15 -0500 Subject: [PATCH] Avoid fragile aliasing of SHA224/384 update/final This is purported to save a few cycles, but makes the code less obvious and more brittle, and in fact breaks on platforms where for ABI continuity reasons there is a SHA2 implementation in libc, and so EVP needs to call those to avoid conflicts. A sufficiently good optimizer could simply generate the same entry points for: foo(...) { ... } and bar(...) { return foo(...); } but, even without that, the different is negligible, with the "winner" varying from run to run (openssl speed -evp sha384): Old: type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes sha384 28864.28k 117362.62k 266469.21k 483258.03k 635144.87k 649123.16k New: type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes sha384 30055.18k 120725.98k 272057.26k 482847.40k 634585.09k 650308.27k Reviewed-by: Rich Salz --- crypto/evp/m_sha1.c | 33 ++++++++++++++++++++++++--------- 1 file changed, 24 insertions(+), 9 deletions(-) diff --git a/crypto/evp/m_sha1.c b/crypto/evp/m_sha1.c index 8f30077a4a..ac0ead3b11 100644 --- a/crypto/evp/m_sha1.c +++ b/crypto/evp/m_sha1.c @@ -115,16 +115,21 @@ static int init224(EVP_MD_CTX *ctx) return SHA224_Init(EVP_MD_CTX_md_data(ctx)); } +static int update224(EVP_MD_CTX *ctx, const void *data, size_t count) +{ + return SHA224_Update(EVP_MD_CTX_md_data(ctx), data, count); +} + +static int final224(EVP_MD_CTX *ctx, unsigned char *md) +{ + return SHA224_Final(md, EVP_MD_CTX_md_data(ctx)); +} + static int init256(EVP_MD_CTX *ctx) { return SHA256_Init(EVP_MD_CTX_md_data(ctx)); } -/* - * Even though there're separate SHA224_[Update|Final], we call - * SHA256 functions even in SHA224 context. This is what happens - * there anyway, so we can spare few CPU cycles:-) - */ static int update256(EVP_MD_CTX *ctx, const void *data, size_t count) { return SHA256_Update(EVP_MD_CTX_md_data(ctx), data, count); @@ -141,8 +146,8 @@ static const EVP_MD sha224_md = { SHA224_DIGEST_LENGTH, EVP_MD_FLAG_DIGALGID_ABSENT, init224, - update256, - final256, + update224, + final224, NULL, NULL, SHA256_CBLOCK, @@ -178,6 +183,16 @@ static int init384(EVP_MD_CTX *ctx) return SHA384_Init(EVP_MD_CTX_md_data(ctx)); } +static int update384(EVP_MD_CTX *ctx, const void *data, size_t count) +{ + return SHA384_Update(EVP_MD_CTX_md_data(ctx), data, count); +} + +static int final384(EVP_MD_CTX *ctx, unsigned char *md) +{ + return SHA384_Final(md, EVP_MD_CTX_md_data(ctx)); +} + static int init512(EVP_MD_CTX *ctx) { return SHA512_Init(EVP_MD_CTX_md_data(ctx)); @@ -200,8 +215,8 @@ static const EVP_MD sha384_md = { SHA384_DIGEST_LENGTH, EVP_MD_FLAG_DIGALGID_ABSENT, init384, - update512, - final512, + update384, + final384, NULL, NULL, SHA512_CBLOCK, -- 2.25.1