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/include/crypto/sig.h b/include/crypto/sig.h
index 11024708c069..fa6dafafab3f 100644
--- a/include/crypto/sig.h
+++ b/include/crypto/sig.h
@@ -128,7 +128,7 @@ static inline void crypto_free_sig(struct crypto_sig *tfm)
 /**
  * crypto_sig_keysize() - Get key size
  *
- * Function returns the key size in bytes.
+ * Function returns the key size in bits.
  * Function assumes that the key is already set in the transformation. If this
  * function is called without a setkey or with a failed setkey, you may end up
  * in a NULL dereference.