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crypto: drbg - remove superflowous memsets 

The DRBG code contains memset(0) calls to initialize a varaible
that are not necessary as the variable is always overwritten by
the processing.

This patch increases the CTR and Hash DRBGs by about 5%.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
hifive-unleashed-5.1
Stephan Mueller 2015-03-01 20:40:17 +01:00 committed by Herbert Xu
parent 04bcbfcf7e
commit 37821da088
1 changed files with 0 additions and 18 deletions
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18
crypto/drbg.c
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@ -308,9 +308,6 @@ static int drbg_ctr_bcc(struct drbg_state *drbg,
drbg_string_fill(&data, out, drbg_blocklen(drbg));
/* 10.4.3 step 1 */
memset(out, 0, drbg_blocklen(drbg));
/* 10.4.3 step 2 / 4 */
list_for_each_entry(curr, in, list) {
const unsigned char *pos = curr->buf;
@ -406,7 +403,6 @@ static int drbg_ctr_df(struct drbg_state *drbg,
memset(pad, 0, drbg_blocklen(drbg));
memset(iv, 0, drbg_blocklen(drbg));
memset(temp, 0, drbg_statelen(drbg));
/* 10.4.2 step 1 is implicit as we work byte-wise */
@ -523,7 +519,6 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
unsigned int len = 0;
struct drbg_string cipherin;
memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
if (3 > reseed)
memset(df_data, 0, drbg_statelen(drbg));
@ -585,8 +580,6 @@ static int drbg_ctr_generate(struct drbg_state *drbg,
int ret = 0;
struct drbg_string data;
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
/* 10.2.1.5.2 step 2 */
if (addtl && !list_empty(addtl)) {
ret = drbg_ctr_update(drbg, addtl, 2);
@ -761,7 +754,6 @@ static struct drbg_state_ops drbg_hmac_ops = {
.generate = drbg_hmac_generate,
.crypto_init = drbg_init_hash_kernel,
.crypto_fini = drbg_fini_hash_kernel,
};
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
@ -838,8 +830,6 @@ static int drbg_hash_df(struct drbg_state *drbg,
unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
struct drbg_string data;
memset(tmp, 0, drbg_blocklen(drbg));
/* 10.4.1 step 3 */
input[0] = 1;
drbg_cpu_to_be32((outlen * 8), &input[1]);
@ -879,7 +869,6 @@ static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
unsigned char *V = drbg->scratchpad;
unsigned char prefix = DRBG_PREFIX1;
memset(drbg->scratchpad, 0, drbg_statelen(drbg));
if (!seed)
return -EINVAL;
@ -921,9 +910,6 @@ static int drbg_hash_process_addtl(struct drbg_state *drbg,
LIST_HEAD(datalist);
unsigned char prefix = DRBG_PREFIX2;
/* this is value w as per documentation */
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
/* 10.1.1.4 step 2 */
if (!addtl || list_empty(addtl))
return 0;
@ -959,9 +945,6 @@ static int drbg_hash_hashgen(struct drbg_state *drbg,
struct drbg_string data;
LIST_HEAD(datalist);
memset(src, 0, drbg_statelen(drbg));
memset(dst, 0, drbg_blocklen(drbg));
/* 10.1.1.4 step hashgen 2 */
memcpy(src, drbg->V, drbg_statelen(drbg));
@ -1018,7 +1001,6 @@ static int drbg_hash_generate(struct drbg_state *drbg,
len = drbg_hash_hashgen(drbg, buf, buflen);
/* this is the value H as documented in 10.1.1.4 */
memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
/* 10.1.1.4 step 4 */
drbg_string_fill(&data1, &prefix, 1);
list_add_tail(&data1.list, &datalist);