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tls: merge sha1 and sha256 hmac functions

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function                                             old     new   delta
hmac_begin                                             -     196    +196
hmac_sha256                                           61      68      +7
hmac                                                 250      87    -163
hmac_sha256_begin                                    190       -    -190
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 1/1 up/down: 203/-353)         Total: -150 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2017-04-03 17:43:44 +02:00
parent 6e99f1cb45
commit 636c3b627c
1 changed files with 12 additions and 44 deletions
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56
networking/tls.c
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@ -367,11 +367,12 @@ static unsigned hmac_sha_precomputed_v(
return sha_end(&pre->hashed_key_xor_opad, out);
}
static void hmac_sha256_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned key_size)
typedef void md5sha_begin_func(md5sha_ctx_t *ctx) FAST_FUNC;
static void hmac_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned key_size, md5sha_begin_func *begin)
{
uint8_t key_xor_ipad[SHA_INSIZE];
uint8_t key_xor_opad[SHA_INSIZE];
uint8_t tempkey[SHA256_OUTSIZE];
uint8_t tempkey[SHA1_OUTSIZE < SHA256_OUTSIZE ? SHA256_OUTSIZE : SHA1_OUTSIZE];
unsigned i;
// "The authentication key can be of any length up to INSIZE, the
@ -380,7 +381,7 @@ static void hmac_sha256_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned ke
// resultant OUTSIZE byte string as the actual key to HMAC."
if (key_size > SHA_INSIZE) {
md5sha_ctx_t ctx;
sha256_begin(&ctx);
begin(&ctx);
md5sha_hash(&ctx, key, key_size);
key_size = sha_end(&ctx, tempkey);
}
@ -394,41 +395,8 @@ static void hmac_sha256_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned ke
key_xor_opad[i] = 0x5c;
}
sha256_begin(&pre->hashed_key_xor_ipad);
sha256_begin(&pre->hashed_key_xor_opad);
md5sha_hash(&pre->hashed_key_xor_ipad, key_xor_ipad, SHA_INSIZE);
md5sha_hash(&pre->hashed_key_xor_opad, key_xor_opad, SHA_INSIZE);
}
// TODO: ^^^ vvv merge?
static void hmac_sha1_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned key_size)
{
uint8_t key_xor_ipad[SHA_INSIZE];
uint8_t key_xor_opad[SHA_INSIZE];
uint8_t tempkey[SHA1_OUTSIZE];
unsigned i;
// "The authentication key can be of any length up to INSIZE, the
// block length of the hash function. Applications that use keys longer
// than INSIZE bytes will first hash the key using H and then use the
// resultant OUTSIZE byte string as the actual key to HMAC."
if (key_size > SHA_INSIZE) {
md5sha_ctx_t ctx;
sha1_begin(&ctx);
md5sha_hash(&ctx, key, key_size);
key_size = sha_end(&ctx, tempkey);
}
for (i = 0; i < key_size; i++) {
key_xor_ipad[i] = key[i] ^ 0x36;
key_xor_opad[i] = key[i] ^ 0x5c;
}
for (; i < SHA_INSIZE; i++) {
key_xor_ipad[i] = 0x36;
key_xor_opad[i] = 0x5c;
}
sha1_begin(&pre->hashed_key_xor_ipad);
sha1_begin(&pre->hashed_key_xor_opad);
begin(&pre->hashed_key_xor_ipad);
begin(&pre->hashed_key_xor_opad);
md5sha_hash(&pre->hashed_key_xor_ipad, key_xor_ipad, SHA_INSIZE);
md5sha_hash(&pre->hashed_key_xor_opad, key_xor_opad, SHA_INSIZE);
}
@ -441,11 +409,11 @@ static unsigned hmac(tls_state_t *tls, uint8_t *out, uint8_t *key, unsigned key_
va_start(va, key_size);
if (tls->MAC_size == SHA256_OUTSIZE)
hmac_sha256_begin(&pre, key, key_size);
else
hmac_sha1_begin(&pre, key, key_size);
hmac_begin(&pre, key, key_size,
(tls->MAC_size == SHA256_OUTSIZE)
? sha256_begin
: sha1_begin
);
len = hmac_sha_precomputed_v(&pre, out, va);
va_end(va);
@ -460,7 +428,7 @@ static unsigned hmac_sha256(/*tls_state_t *tls,*/ uint8_t *out, uint8_t *key, un
va_start(va, key_size);
hmac_sha256_begin(&pre, key, key_size);
hmac_begin(&pre, key, key_size, sha256_begin);
len = hmac_sha_precomputed_v(&pre, out, va);
va_end(va);