1 files changed, 39 insertions, 5 deletions

diff --git a/crypto/ecc.c b/crypto/ecc.c
index 02d35be7702b..8acf8433ca29 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -940,7 +940,7 @@ static bool ecc_point_is_zero(const struct ecc_point *point)
 }
 
 /* Point multiplication algorithm using Montgomery's ladder with co-Z
- * coordinates. From http://eprint.iacr.org/2011/338.pdf
+ * coordinates. From https://eprint.iacr.org/2011/338.pdf
  */
 
 /* Double in place */
@@ -1404,7 +1404,9 @@ int ecc_make_pub_key(unsigned int curve_id, unsigned int ndigits,
 	}
 
 	ecc_point_mult(pk, &curve->g, priv, NULL, curve, ndigits);
-	if (ecc_point_is_zero(pk)) {
+
+	/* SP800-56A rev 3 5.6.2.1.3 key check */
+	if (ecc_is_pubkey_valid_full(curve, pk)) {
 		ret = -EAGAIN;
 		goto err_free_point;
 	}
@@ -1452,6 +1454,33 @@ int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
 }
 EXPORT_SYMBOL(ecc_is_pubkey_valid_partial);
 
+/* SP800-56A section 5.6.2.3.3 full verification */
+int ecc_is_pubkey_valid_full(const struct ecc_curve *curve,
+			     struct ecc_point *pk)
+{
+	struct ecc_point *nQ;
+
+	/* Checks 1 through 3 */
+	int ret = ecc_is_pubkey_valid_partial(curve, pk);
+
+	if (ret)
+		return ret;
+
+	/* Check 4: Verify that nQ is the zero point. */
+	nQ = ecc_alloc_point(pk->ndigits);
+	if (!nQ)
+		return -ENOMEM;
+
+	ecc_point_mult(nQ, pk, curve->n, NULL, curve, pk->ndigits);
+	if (!ecc_point_is_zero(nQ))
+		ret = -EINVAL;
+
+	ecc_free_point(nQ);
+
+	return ret;
+}
+EXPORT_SYMBOL(ecc_is_pubkey_valid_full);
+
 int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
 			      const u64 *private_key, const u64 *public_key,
 			      u64 *secret)
@@ -1495,11 +1524,16 @@ int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
 
 	ecc_point_mult(product, pk, priv, rand_z, curve, ndigits);
 
-	ecc_swap_digits(product->x, secret, ndigits);
-
-	if (ecc_point_is_zero(product))
+	if (ecc_point_is_zero(product)) {
 		ret = -EFAULT;
+		goto err_validity;
+	}
+
+	ecc_swap_digits(product->x, secret, ndigits);
 
+err_validity:
+	memzero_explicit(priv, sizeof(priv));
+	memzero_explicit(rand_z, sizeof(rand_z));
 	ecc_free_point(product);
 err_alloc_product:
 	ecc_free_point(pk);