Patch "crypto: ecdsa - Rename keylen to bufsize where necessary" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    crypto: ecdsa - Rename keylen to bufsize where necessary

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     crypto-ecdsa-rename-keylen-to-bufsize-where-necessar.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6bbf61bedb7d51bc6aed1110b9c58e0fc950b14c
Author: Stefan Berger <stefanb@xxxxxxxxxxxxx>
Date:   Thu Apr 4 10:18:53 2024 -0400

    crypto: ecdsa - Rename keylen to bufsize where necessary
    
    [ Upstream commit 703ca5cda1ea04735e48882a7cccff97d57656c3 ]
    
    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.
    
    Tested-by: Lukas Wunner <lukas@xxxxxxxxx>
    Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
    Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
    Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
    Stable-dep-of: 3b0565c70350 ("crypto: ecdsa - Avoid signed integer overflow on signature decoding")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
index e819d0983bd3..142bed98fa97 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);