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>
Tested-by: Lukas Wunner <lukas@wunner.de>
---
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);
+ 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);
--
2.43.0On Thu Mar 7, 2024 at 12:22 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>
> Tested-by: Lukas Wunner <lukas@wunner.de>
> ---
> 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);
nit: still don't get why "* sizeof(u64)" would ever be more readable
thean "* 8".
BR, Jarkko
On 3/7/24 14:13, Jarkko Sakkinen wrote:
> On Thu Mar 7, 2024 at 12:22 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>
>> Tested-by: Lukas Wunner <lukas@wunner.de>
>> ---
>> 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);
>
> nit: still don't get why "* sizeof(u64)" would ever be more readable
> thean "* 8".
Because existing code in crypto uses sizeof(u64) when converting ndigits
to number of bytes and '8' is not used for converting to bytes. Do we
need to change this now ? No, I think it's better to conform to existing
code.
# grep -rI ndigits crypto/ | grep sizeof\(u64\)
crypto/ecrdsa.c: unsigned int ndigits = req->dst_len / sizeof(u64);
crypto/ecrdsa.c: req->dst_len != ctx->curve->g.ndigits *
sizeof(u64) ||
crypto/ecrdsa.c: vli_from_be64(r, sig + ndigits * sizeof(u64),
ndigits);
crypto/ecrdsa.c: ctx->curve->g.ndigits * sizeof(u64) !=
ctx->digest_len)
crypto/ecrdsa.c: ctx->key_len != ctx->curve->g.ndigits *
sizeof(u64) * 2)
crypto/ecrdsa.c: ndigits = ctx->key_len / sizeof(u64) / 2;
crypto/ecrdsa.c: vli_from_le64(ctx->pub_key.y, ctx->key + ndigits
* sizeof(u64),
crypto/ecrdsa.c: return ctx->pub_key.ndigits * sizeof(u64);
crypto/ecdh.c: params.key_size > sizeof(u64) * ctx->ndigits)
crypto/ecc.c: size_t len = ndigits * sizeof(u64);
crypto/ecc.c: num_bits = sizeof(u64) * ndigits * 8 + 1;
crypto/ecdsa.c: size_t bufsize = ndigits * sizeof(u64);
crypto/ecdsa.c: size_t bufsize = ctx->curve->g.ndigits * sizeof(u64);
crypto/ecdsa.c: ndigits = DIV_ROUND_UP(digitlen, sizeof(u64));
Stefan
>
> BR, Jarkko
Jarkko,
On Thu, Mar 07, 2024 at 02:20:12PM -0500, Stefan Berger wrote:
> On 3/7/24 14:13, Jarkko Sakkinen wrote:
> > On Thu Mar 7, 2024 at 12:22 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>
> > > Tested-by: Lukas Wunner <lukas@wunner.de>
> > > ---
> > > 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);
> >
> > nit: still don't get why "* sizeof(u64)" would ever be more readable
> > thean "* 8".
>
> Because existing code in crypto uses sizeof(u64) when converting ndigits to
> number of bytes and '8' is not used for converting to bytes. Do we need to
> change this now ? No, I think it's better to conform to existing code.
`sizeof(u64)` is easily read as `8` by reviewers, but just `8` will
require inline comments because it's magic number isn't it? So this will
not even decrease number of letters.
`sizeof(u64)` is self-documenting code and you don't even need to
interpret it as `8` for review as you don't need number from any
sizeof(struct ..).
Also, possible we need to calculate number of bits in the big number, so
this would become `* 8 * 8`, in that case how would you distinguish
omission of one `* 8` by a typo.
Overall it's quite common in the whole tree
linux/torvalds$ git grep -e '\* sizeof(u64)' -e 'sizeof(u64) \*' | wc -l
551
So this is perhaps acceptable and depends on point of view. crypto
subsystem coders seems to prefer not to save on letters and type
`sizeof(u64)`.
Thanks,
>
> # grep -rI ndigits crypto/ | grep sizeof\(u64\)
> crypto/ecrdsa.c: unsigned int ndigits = req->dst_len / sizeof(u64);
> crypto/ecrdsa.c: req->dst_len != ctx->curve->g.ndigits *
> sizeof(u64) ||
> crypto/ecrdsa.c: vli_from_be64(r, sig + ndigits * sizeof(u64),
> ndigits);
> crypto/ecrdsa.c: ctx->curve->g.ndigits * sizeof(u64) !=
> ctx->digest_len)
> crypto/ecrdsa.c: ctx->key_len != ctx->curve->g.ndigits *
> sizeof(u64) * 2)
> crypto/ecrdsa.c: ndigits = ctx->key_len / sizeof(u64) / 2;
> crypto/ecrdsa.c: vli_from_le64(ctx->pub_key.y, ctx->key + ndigits *
> sizeof(u64),
> crypto/ecrdsa.c: return ctx->pub_key.ndigits * sizeof(u64);
> crypto/ecdh.c: params.key_size > sizeof(u64) * ctx->ndigits)
> crypto/ecc.c: size_t len = ndigits * sizeof(u64);
> crypto/ecc.c: num_bits = sizeof(u64) * ndigits * 8 + 1;
> crypto/ecdsa.c: size_t bufsize = ndigits * sizeof(u64);
> crypto/ecdsa.c: size_t bufsize = ctx->curve->g.ndigits * sizeof(u64);
> crypto/ecdsa.c: ndigits = DIV_ROUND_UP(digitlen, sizeof(u64));
>
> Stefan
>
> >
> > BR, Jarkko
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