Implement ecc_curve_get_nbytes to get a curve's number of bytes (nbytes).
The number of bytes can be derived from the nbits field of a curve, if
set, otherwise from the ndigits field.
Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
---
crypto/ecc.c | 6 ++----
include/crypto/internal/ecc.h | 11 +++++++++++
2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/crypto/ecc.c b/crypto/ecc.c
index 73fbbfc8d69c..f643719450b8 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -1478,10 +1478,8 @@ static int __ecc_is_key_valid(const struct ecc_curve *curve,
int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
const u64 *private_key, unsigned int private_key_len)
{
- int nbytes;
const struct ecc_curve *curve = ecc_get_curve(curve_id);
-
- nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+ int nbytes = ecc_curve_get_nbytes(curve);
if (private_key_len != nbytes)
return -EINVAL;
@@ -1506,7 +1504,7 @@ int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)
{
const struct ecc_curve *curve = ecc_get_curve(curve_id);
u64 priv[ECC_MAX_DIGITS];
- unsigned int nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+ unsigned int nbytes = ecc_curve_get_nbytes(curve);
unsigned int nbits = vli_num_bits(curve->n, ndigits);
int err;
diff --git a/include/crypto/internal/ecc.h b/include/crypto/internal/ecc.h
index 6229aa3f3218..5d485d3221d3 100644
--- a/include/crypto/internal/ecc.h
+++ b/include/crypto/internal/ecc.h
@@ -93,6 +93,17 @@ static inline void ecc_digits_to_bytes(const u64 *in, unsigned int ndigits,
memcpy(out, &tmp[o], nbytes);
}
+/**
+ * ecc_curve_get_nbytes() - Get the number of bytes the curve requires
+ * @curve: The curve
+ */
+static inline unsigned int ecc_curve_get_nbytes(const struct ecc_curve *curve)
+{
+ if (curve->nbits)
+ return DIV_ROUND_UP(curve->nbits, 8);
+ return curve->g.ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+}
+
/**
* ecc_is_key_valid() - Validate a given ECDH private key
*
--
2.43.0
