Since ecc_digits_from_bytes will provide zeros when an insufficient number
of bytes are passed in the input byte array, use it to convert the r and s
components of the signature to digits directly from the input byte
array. This avoids going through an intermediate byte array that has the
first few bytes filled with zeros.
Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
---
crypto/ecdsa.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
index fa029f36110b..941cdc2b889b 100644
--- a/crypto/ecdsa.c
+++ b/crypto/ecdsa.c
@@ -38,7 +38,6 @@ static int ecdsa_get_signature_rs(u64 *dest, size_t hdrlen, unsigned char tag,
size_t bufsize = ndigits * sizeof(u64);
ssize_t diff = vlen - bufsize;
const char *d = value;
- u8 rs[ECC_MAX_BYTES];
if (!value || !vlen)
return -EINVAL;
@@ -46,7 +45,7 @@ static int ecdsa_get_signature_rs(u64 *dest, size_t hdrlen, unsigned char tag,
/* diff = 0: 'value' has exacly the right size
* diff > 0: 'value' has too many bytes; one leading zero is allowed that
* makes the value a positive integer; error on more
- * diff < 0: 'value' is missing leading zeros, which we add
+ * diff < 0: 'value' is missing leading zeros
*/
if (diff > 0) {
/* skip over leading zeros that make 'value' a positive int */
@@ -61,14 +60,7 @@ static int ecdsa_get_signature_rs(u64 *dest, size_t hdrlen, unsigned char tag,
if (-diff >= bufsize)
return -EINVAL;
- if (diff) {
- /* leading zeros not given in 'value' */
- memset(rs, 0, -diff);
- }
-
- memcpy(&rs[-diff], d, vlen);
-
- ecc_swap_digits((u64 *)rs, dest, ndigits);
+ ecc_digits_from_bytes(d, vlen, dest, ndigits);
return 0;
}
--
2.43.0
