crypto: ecdsa - Fix NIST P521 key size reported by KEYCTL_PKEY_QUERY

When user space issues a KEYCTL_PKEY_QUERY system call for a NIST P521
key, the key_size is incorrectly reported as 528 bits instead of 521.

That's because the key size obtained through crypto_sig_keysize() is in
bytes and software_key_query() multiplies by 8 to yield the size in bits.
The underlying assumption is that the key size is always a multiple of 8.
With the recent addition of NIST P521, that's no longer the case.

Fix by returning the key_size in bits from crypto_sig_keysize() and
adjusting the calculations in software_key_query().

The ->key_size() callbacks of sig_alg algorithms now return the size in
bits, whereas the ->digest_size() and ->max_size() callbacks return the
size in bytes.  This matches with the units in struct keyctl_pkey_query.

Fixes: a7d45ba77d3d ("crypto: ecdsa - Register NIST P521 and extend test suite")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 1 insertions, 1 deletions

diff --git a/crypto/rsassa-pkcs1.c b/crypto/rsassa-pkcs1.c
index d01ac75635e0..94fa5e9600e7 100644
--- a/crypto/rsassa-pkcs1.c
+++ b/crypto/rsassa-pkcs1.c
@@ -301,7 +301,7 @@ static unsigned int rsassa_pkcs1_key_size(struct crypto_sig *tfm)
 {
 	struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm);
 
-	return ctx->key_size;
+	return ctx->key_size * BITS_PER_BYTE;
 }
 
 static int rsassa_pkcs1_set_pub_key(struct crypto_sig *tfm,