crypto: sm2 - fix a memory leak in sm2

SM2 module alloc ec->Q in sm2_set_pub_key(), when doing alg test in
test_akcipher_one(), it will set public key for every test vector,
and don't free ec->Q. This will cause a memory leak.

This patch alloc ec->Q in sm2_ec_ctx_init().

Fixes: ea7ecb66 ("crypto: sm2 - introduce OSCCA SM2 asymmetric cipher algorithm")
Signed-off-by: Hongbo Li <herberthbli@tencent.com>
Reviewed-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/sm2.c

@@ -79,10 +79,17 @@ static int sm2_ec_ctx_init(struct mpi_ec_ctx *ec)
 		goto free;
 
 	rc = -ENOMEM;
+
+	ec->Q = mpi_point_new(0);
+	if (!ec->Q)
+		goto free;
+
 	/* mpi_ec_setup_elliptic_curve */
 	ec->G = mpi_point_new(0);
-	if (!ec->G)
+	if (!ec->G) {
+		mpi_point_release(ec->Q);
 		goto free;
+	}
 
 	mpi_set(ec->G->x, x);
 	mpi_set(ec->G->y, y);
@@ -91,6 +98,7 @@ static int sm2_ec_ctx_init(struct mpi_ec_ctx *ec)
 	rc = -EINVAL;
 	ec->n = mpi_scanval(ecp->n);
 	if (!ec->n) {
+		mpi_point_release(ec->Q);
 		mpi_point_release(ec->G);
 		goto free;
 	}
@@ -386,27 +394,15 @@ static int sm2_set_pub_key(struct crypto_akcipher *tfm,
 	MPI a;
 	int rc;
 
-	ec->Q = mpi_point_new(0);
-	if (!ec->Q)
-		return -ENOMEM;
-
 	/* include the uncompressed flag '0x04' */
-	rc = -ENOMEM;
 	a = mpi_read_raw_data(key, keylen);
 	if (!a)
-		goto error;
+		return -ENOMEM;
 
 	mpi_normalize(a);
 	rc = sm2_ecc_os2ec(ec->Q, a);
 	mpi_free(a);
-	if (rc)
-		goto error;
-
-	return 0;
 
-error:
-	mpi_point_release(ec->Q);
-	ec->Q = NULL;
 	return rc;
 }