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 <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/drbg.c b/crypto/drbg.c
index d8ff16e5c3224869c9cdc10fd01ae4ad175ee240..c14274ac8d61bfbed4201485e68de822d5b46d32 100644 (file)
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -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 */