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crypto: sm2 - remove unnecessary reset operations

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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: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Tianjia Zhang 2020-10-15 17:24:41 +08:00 committed by Herbert Xu
parent ad0bb4e4d2
commit 1bc608b465
1 changed files with 29 additions and 46 deletions
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75
crypto/sm2.c
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@ -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;
}
n = (n-1)/2;
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;