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[v7,10/13] crypto: ecdsa - Rename keylen to bufsize where necessary

Message ID 20240320114725.1644921-11-stefanb@linux.ibm.com (mailing list archive)
State Changes Requested
Delegated to: Herbert Xu
Headers show
Series [v7,01/13] crypto: ecc - Use ECC_CURVE_NIST_P192/256/384_DIGITS where possible | expand

Commit Message

Stefan Berger March 20, 2024, 11:47 a.m. UTC
In cases where 'keylen' was referring to the size of the buffer used by
a curve's digits, it does not reflect the purpose of the variable anymore
once NIST P521 is used. What it refers to then is the size of the buffer,
which may be a few bytes larger than the size a coordinate of a key.
Therefore, 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(-)

Comments

Jarkko Sakkinen March 21, 2024, 5:19 p.m. UTC | #1
On Wed Mar 20, 2024 at 1:47 PM EET, Stefan Berger wrote:
> In cases where 'keylen' was referring to the size of the buffer used by
> a curve's digits, it does not reflect the purpose of the variable anymore
> once NIST P521 is used. What it refers to then is the size of the buffer,
> which may be a few bytes larger than the size a coordinate of a key.
> Therefore, 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);


Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

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);