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Commit 4218ebe8 authored by Stephan Mueller's avatar Stephan Mueller Committed by Herbert Xu
Browse files

crypto: drbg - set HMAC key only when altered 



The HMAC implementation allows setting the HMAC key independently from
the hashing operation. Therefore, the key only needs to be set when a
new key is generated.

This patch increases the speed of the HMAC DRBG by at least 35% depending
on the use case.

The patch is fully CAVS tested.

Signed-off-by: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent bdb6cf9f

crypto/drbg.c

+25 −14
Original line number Diff line number Diff line
@@ -592,8 +592,10 @@ static const struct drbg_state_ops drbg_ctr_ops = { 
 ******************************************************************/



#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)

static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,

			   unsigned char *outval, const struct list_head *in);

static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,

			   const struct list_head *in);

static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,

				  const unsigned char *key);

static int drbg_init_hash_kernel(struct drbg_state *drbg);

static int drbg_fini_hash_kernel(struct drbg_state *drbg);

#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
@@ -619,9 +621,11 @@ static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed, 
	LIST_HEAD(seedlist);

	LIST_HEAD(vdatalist);



	if (!reseed)

	if (!reseed) {

		/* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */

		memset(drbg->V, 1, drbg_statelen(drbg));

		drbg_kcapi_hmacsetkey(drbg, drbg->C);

	}



	drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));

	list_add_tail(&seed1.list, &seedlist);
@@ -641,12 +645,13 @@ static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed, 
			prefix = DRBG_PREFIX1;

		/* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */

		seed2.buf = &prefix;

		ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist);

		ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);

		if (ret)

			return ret;

		drbg_kcapi_hmacsetkey(drbg, drbg->C);



		/* 10.1.2.2 step 2 and 5 -- HMAC for V */

		ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist);

		ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);

		if (ret)

			return ret;
@@ -681,7 +686,7 @@ static int drbg_hmac_generate(struct drbg_state *drbg, 
	while (len < buflen) {

		unsigned int outlen = 0;

		/* 10.1.2.5 step 4.1 */

		ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist);

		ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);

		if (ret)

			return ret;

		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
@@ -796,7 +801,7 @@ static int drbg_hash_df(struct drbg_state *drbg, 
	while (len < outlen) {

		short blocklen = 0;

		/* 10.4.1 step 4.1 */

		ret = drbg_kcapi_hash(drbg, NULL, tmp, entropylist);

		ret = drbg_kcapi_hash(drbg, tmp, entropylist);

		if (ret)

			goto out;

		/* 10.4.1 step 4.2 */
@@ -874,7 +879,7 @@ static int drbg_hash_process_addtl(struct drbg_state *drbg, 
	list_add_tail(&data1.list, &datalist);

	list_add_tail(&data2.list, &datalist);

	list_splice_tail(addtl, &datalist);

	ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);

	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);

	if (ret)

		goto out;
@@ -907,7 +912,7 @@ static int drbg_hash_hashgen(struct drbg_state *drbg, 
	while (len < buflen) {

		unsigned int outlen = 0;

		/* 10.1.1.4 step hashgen 4.1 */

		ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist);

		ret = drbg_kcapi_hash(drbg, dst, &datalist);

		if (ret) {

			len = ret;

			goto out;
@@ -956,7 +961,7 @@ static int drbg_hash_generate(struct drbg_state *drbg, 
	list_add_tail(&data1.list, &datalist);

	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));

	list_add_tail(&data2.list, &datalist);

	ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);

	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);

	if (ret) {

		len = ret;

		goto out;
@@ -1600,14 +1605,20 @@ static int drbg_fini_hash_kernel(struct drbg_state *drbg) 
	return 0;

}



static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,

			   unsigned char *outval, const struct list_head *in)

static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,

				  const unsigned char *key)

{

	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;

	struct drbg_string *input = NULL;



	if (key)

	crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));

}



static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,

			   const struct list_head *in)

{

	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;

	struct drbg_string *input = NULL;



	crypto_shash_init(&sdesc->shash);

	list_for_each_entry(input, in, list)

		crypto_shash_update(&sdesc->shash, input->buf, input->len);