Commit 1bc608b4 authored by Tianjia Zhang's avatar Tianjia Zhang Committed by Herbert Xu
Browse files

crypto: sm2 - remove unnecessary reset operations 



This is an algorithm optimization. The reset operation when
setting the public key is repeated and redundant, so remove it.
At the same time, `sm2_ecc_os2ec()` is optimized to make the
function more simpler and more in line with the Linux code style.

Signed-off-by: default avatarTianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent ad0bb4e4

crypto/sm2.c

+29 −46
Original line number Diff line number Diff line
@@ -119,12 +119,6 @@ static void sm2_ec_ctx_deinit(struct mpi_ec_ctx *ec) 
	memset(ec, 0, sizeof(*ec));

}



static int sm2_ec_ctx_reset(struct mpi_ec_ctx *ec)

{

	sm2_ec_ctx_deinit(ec);

	return sm2_ec_ctx_init(ec);

}



/* RESULT must have been initialized and is set on success to the

 * point given by VALUE.

 */
@@ -132,55 +126,48 @@ static int sm2_ecc_os2ec(MPI_POINT result, MPI value) 
{

	int rc;

	size_t n;

	const unsigned char *buf;

	unsigned char *buf_memory;

	unsigned char *buf;

	MPI x, y;



	n = (mpi_get_nbits(value)+7)/8;

	buf_memory = kmalloc(n, GFP_KERNEL);

	rc = mpi_print(GCRYMPI_FMT_USG, buf_memory, n, &n, value);

	if (rc) {

		kfree(buf_memory);

		return rc;

	}

	buf = buf_memory;

	n = MPI_NBYTES(value);

	buf = kmalloc(n, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	if (n < 1) {

		kfree(buf_memory);

		return -EINVAL;

	}

	if (*buf != 4) {

		kfree(buf_memory);

		return -EINVAL; /* No support for point compression.  */

	}

	if (((n-1)%2)) {

		kfree(buf_memory);

		return -EINVAL;

	}

	rc = mpi_print(GCRYMPI_FMT_USG, buf, n, &n, value);

	if (rc)

		goto err_freebuf;



	rc = -EINVAL;

	if (n < 1 || ((n - 1) % 2))

		goto err_freebuf;

	/* No support for point compression */

	if (*buf != 0x4)

		goto err_freebuf;



	rc = -ENOMEM;

	n = (n - 1) / 2;

	x = mpi_read_raw_data(buf + 1, n);

	if (!x) {

		kfree(buf_memory);

		return -ENOMEM;

	}

	if (!x)

		goto err_freebuf;

	y = mpi_read_raw_data(buf + 1 + n, n);

	kfree(buf_memory);

	if (!y) {

		mpi_free(x);

		return -ENOMEM;

	}

	if (!y)

		goto err_freex;



	mpi_normalize(x);

	mpi_normalize(y);



	mpi_set(result->x, x);

	mpi_set(result->y, y);

	mpi_set_ui(result->z, 1);



	mpi_free(x);

	mpi_free(y);

	rc = 0;



	return 0;

	mpi_free(y);

err_freex:

	mpi_free(x);

err_freebuf:

	kfree(buf);

	return rc;

}



struct sm2_signature_ctx {
@@ -399,10 +386,6 @@ static int sm2_set_pub_key(struct crypto_akcipher *tfm, 
	MPI a;

	int rc;



	rc = sm2_ec_ctx_reset(ec);

	if (rc)

		return rc;



	ec->Q = mpi_point_new(0);

	if (!ec->Q)

		return -ENOMEM;