Commit 546ce0bd authored by Stefan Berger's avatar Stefan Berger Committed by Herbert Xu
Browse files

crypto: ecdsa - Use ecc_digits_from_bytes to convert signature 



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: default avatarStefan Berger <stefanb@linux.ibm.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 2fd2a82c

crypto/ecdsa.c

+2 −10
Original line number Diff line number Diff line
@@ -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;

}