diff mbox series

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

Message ID 20240301022007.344948-10-stefanb@linux.ibm.com
State New
Headers
Series Add support for NIST P521 to ecdsa |

Commit Message

Stefan Berger March 1, 2024, 2:20 a.m. UTC 
  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(-)

Comments

Jarkko Sakkinen March 1, 2024, 8:41 p.m. UTC | #1 
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
Stefan Berger March 1, 2024, 8:47 p.m. UTC | #2 
On 3/1/24 15:41, Jarkko Sakkinen wrote:
> 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.

'unreadable' is a 'strong' word ...

# grep -r -E "ndigits \*" crypto/ | grep sizeof
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:        vli_from_le64(ctx->pub_key.y, ctx->key + ndigits 
* sizeof(u64),
crypto/ecrdsa.c:        return ctx->pub_key.ndigits * sizeof(u64);
crypto/ecc.c:   size_t len = ndigits * sizeof(u64);
crypto/ecc.c:   num_bits = sizeof(u64) * ndigits * 8 + 1;
crypto/ecdsa.c: size_t keylen = ndigits * sizeof(u64);
crypto/ecdsa.c: size_t keylen = ctx->curve->g.ndigits * sizeof(u64);

    Stefan
Jarkko Sakkinen March 1, 2024, 8:50 p.m. UTC | #3 
On Fri Mar 1, 2024 at 10:47 PM EET, Stefan Berger wrote:
>
>
> On 3/1/24 15:41, Jarkko Sakkinen wrote:
> > 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.
>
> 'unreadable' is a 'strong' word ...

so what is the gain when writing sizeof(u64)?

BR, Jarkko
Stefan Berger March 1, 2024, 9:20 p.m. UTC | #4 
On 3/1/24 15:50, Jarkko Sakkinen wrote:
> On Fri Mar 1, 2024 at 10:47 PM EET, Stefan Berger wrote:
>>
>>
>> On 3/1/24 15:41, Jarkko Sakkinen wrote:
>>> 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.
>>
>> 'unreadable' is a 'strong' word ...
> 
> so what is the gain when writing sizeof(u64)?

It matches existing code and a digit is a 'u64'.


> 
> BR, Jarkko
diff mbox series

Patch

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);