From 37821da088d090d8e152f3f8cc072948fa544e5a Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Sun, 1 Mar 2015 20:40:17 +0100 Subject: [PATCH] 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 Signed-off-by: Herbert Xu --- crypto/drbg.c | 18 ------------------ 1 file changed, 18 deletions(-) diff --git a/crypto/drbg.c b/crypto/drbg.c index c14274ac8d61..56c1d7ec3d9e 100644 --- a/crypto/drbg.c +++ b/crypto/drbg.c @@ -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); -- 2.30.2