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Commit 04bcbfcf authored by Stephan Mueller's avatar Stephan Mueller Committed by Herbert Xu
Browse files

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: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent e8e59953

crypto/drbg.c

+16 −23
Original line number Diff line number Diff line
@@ -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 */