Re: [PATCH v4 09/12] crypto: ecdsa - Rename keylen to bufsize where necessary

Jarkko Sakkinen
2024-03-01T20:41:15Z

On Fri Mar 1, 2024 at 4:20 AM EET, Stefan Berger wrote:
> In some cases the name keylen does not reflect the purpose of the variable
> anymore once NIST P521 is used but it is the size of the buffer. There-
> for, rename keylen to bufsize where appropriate.
>
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> ---
> crypto/ecdsa.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
> index 4daefb40c37a..4e847b59622a 100644
> --- a/crypto/ecdsa.c
> +++ b/crypto/ecdsa.c
> @@ -35,8 +35,8 @@ struct ecdsa_signature_ctx {
> static int ecdsa_get_signature_rs(u64 *dest, size_t hdrlen, unsigned char tag,
> const void *value, size_t vlen, unsigned int ndigits)
> {
> - size_t keylen = ndigits * sizeof(u64);
> - ssize_t diff = vlen - keylen;
> + size_t bufsize = ndigits * sizeof(u64);

why not just "* 8"? using sizeof here makes this function only unreadable.

> + ssize_t diff = vlen - bufsize;
> const char *d = value;
> u8 rs[ECC_MAX_BYTES];
>
> @@ -58,7 +58,7 @@ static int ecdsa_get_signature_rs(u64 *dest, size_t hdrlen, unsigned char tag,
> if (diff)
> return -EINVAL;
> }
> - if (-diff >= keylen)
> + if (-diff >= bufsize)
> return -EINVAL;
>
> if (diff) {
> @@ -138,7 +138,7 @@ static int ecdsa_verify(struct akcipher_request *req)
> {
> struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
> struct ecc_ctx *ctx = akcipher_tfm_ctx(tfm);
> - size_t keylen = ctx->curve->g.ndigits * sizeof(u64);
> + size_t bufsize = ctx->curve->g.ndigits * sizeof(u64);
> struct ecdsa_signature_ctx sig_ctx = {
> .curve = ctx->curve,
> };
> @@ -165,14 +165,14 @@ static int ecdsa_verify(struct akcipher_request *req)
> goto error;
>
> /* if the hash is shorter then we will add leading zeros to fit to ndigits */
> - diff = keylen - req->dst_len;
> + diff = bufsize - req->dst_len;
> if (diff >= 0) {
> if (diff)
> memset(rawhash, 0, diff);
> memcpy(&rawhash[diff], buffer + req->src_len, req->dst_len);
> } else if (diff < 0) {
> /* given hash is longer, we take the left-most bytes */
> - memcpy(&rawhash, buffer + req->src_len, keylen);
> + memcpy(&rawhash, buffer + req->src_len, bufsize);
> }
>
> ecc_swap_digits((u64 *)rawhash, hash, ctx->curve->g.ndigits);

BR, Jarkko