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crypto: drbg: performance improvements

PATCH In review Stephan Mueller 2 participants 4 messages Mar 1, 2015 – Mar 4, 2015 Crypto API

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Stephan Mueller

author
#0 lore raw

cover crypto: drbg: performance improvements

Hi,

The following patches increase the performance of the CTR DRBG and Hash DRBG.

The updates successfully pass the CAVS testing. for Hash DRBG and CTR DRBG.

Stephan Mueller (2):
crypto: drbg: use single block cipher API
crypto: drbg: remove superflowous memsets

 crypto/drbg.c | 57 ++++++++++++++++-----------------------------------------
 1 file changed, 16 insertions(+), 41 deletions(-)
Signature · 1 line
2.1.0
author
#1 lore raw

PATCH 1/2 crypto: drbg: use single block cipher API

The CTR DRBG only encrypts one single block at a time. Thus, use the single block crypto API to avoid additional overhead from the block chaining modes.

With the patch, the speed of the DRBG increases between 30% and 40%.

The DRBG still passes the CTR DRBG CAVS test.

Signed-off-by Stephan Mueller <[email protected]>
---
 crypto/drbg.c | 39 ++++++++++++++++-----------------------
 1 file changed, 16 insertions(+), 23 deletions(-)
crypto/drbg.c +16 -23
index d8ff16e..c14274a 100644
@@ -119,19 +119,19 @@ static const struct drbg_core drbg_cores[] = {
 		.statelen = 32, /* 256 bits as defined in 10.2.1 */
 		.blocklen_bytes = 16,
 		.cra_name = "ctr_aes128",
-		.backend_cra_name = "ecb(aes)",
+		.backend_cra_name = "aes",
 	}, {
 		.flags = DRBG_CTR | DRBG_STRENGTH192,
 		.statelen = 40, /* 320 bits as defined in 10.2.1 */
 		.blocklen_bytes = 16,
 		.cra_name = "ctr_aes192",
-		.backend_cra_name = "ecb(aes)",
+		.backend_cra_name = "aes",
 	}, {
 		.flags = DRBG_CTR | DRBG_STRENGTH256,
 		.statelen = 48, /* 384 bits as defined in 10.2.1 */
 		.blocklen_bytes = 16,
 		.cra_name = "ctr_aes256",
-		.backend_cra_name = "ecb(aes)",
+		.backend_cra_name = "aes",
 	},
 #endif /* CONFIG_CRYPTO_DRBG_CTR */
 #ifdef CONFIG_CRYPTO_DRBG_HASH

@@ -1644,24 +1644,24 @@ static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
 static int drbg_init_sym_kernel(struct drbg_state *drbg)
 {
 	int ret = 0;
-	struct crypto_blkcipher *tfm;
+	struct crypto_cipher *tfm;
 
-	tfm = crypto_alloc_blkcipher(drbg->core->backend_cra_name, 0, 0);
+	tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
 	if (IS_ERR(tfm)) {
 		pr_info("DRBG: could not allocate cipher TFM handle\n");
 		return PTR_ERR(tfm);
 	}
-	BUG_ON(drbg_blocklen(drbg) != crypto_blkcipher_blocksize(tfm));
+	BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
 	drbg->priv_data = tfm;
 	return ret;
 }
 
 static int drbg_fini_sym_kernel(struct drbg_state *drbg)
 {
-	struct crypto_blkcipher *tfm =
-		(struct crypto_blkcipher *)drbg->priv_data;
+	struct crypto_cipher *tfm =
+		(struct crypto_cipher *)drbg->priv_data;
 	if (tfm)
-		crypto_free_blkcipher(tfm);
+		crypto_free_cipher(tfm);
 	drbg->priv_data = NULL;
 	return 0;
 }

@@ -1669,21 +1669,14 @@ static int drbg_fini_sym_kernel(struct drbg_state *drbg)
 static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
 			  unsigned char *outval, const struct drbg_string *in)
 {
-	int ret = 0;
-	struct scatterlist sg_in, sg_out;
-	struct blkcipher_desc desc;
-	struct crypto_blkcipher *tfm =
-		(struct crypto_blkcipher *)drbg->priv_data;
-
-	desc.tfm = tfm;
-	desc.flags = 0;
-	crypto_blkcipher_setkey(tfm, key, (drbg_keylen(drbg)));
-	/* there is only component in *in */
-	sg_init_one(&sg_in, in->buf, in->len);
-	sg_init_one(&sg_out, outval, drbg_blocklen(drbg));
-	ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, in->len);
+	struct crypto_cipher *tfm =
+		(struct crypto_cipher *)drbg->priv_data;
 
-	return ret;
+	crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
+	/* there is only component in *in */
+	BUG_ON(in->len < drbg_blocklen(drbg));
+	crypto_cipher_encrypt_one(tfm, outval, in->buf);
+	return 0;
 }
 #endif /* CONFIG_CRYPTO_DRBG_CTR */
Signature · 1 line
2.1.0
author
#2 lore raw

PATCH 2/2 crypto: drbg: remove superflowous memsets

In reply to Stephan Mueller

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 <[email protected]>
---
 crypto/drbg.c | 18 ------------------
 1 file changed, 18 deletions(-)
crypto/drbg.c +0 -18
index c14274a..56c1d7e 100644
@@ -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);
Signature · 1 line
2.1.0
maintainer
#3 lore raw
In reply to Stephan Mueller
Quoted 11 lines · Stephan Mueller

Hi,

The following patches increase the performance of the CTR DRBG and Hash DRBG.

The updates successfully pass the CAVS testing. for Hash DRBG and CTR DRBG.

Stephan Mueller (2):
crypto: drbg: use single block cipher API
crypto: drbg: remove superflowous memsets

All applied.

Signature · 3 lines
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt