In preparation for support of NIST P521, adjust the basic tests on the
length of the provided key parameter to only ensure that the length of the
x plus y coordinates parameter array is not an odd number and that each
coordinate fits into an array of 'ndigits' digits. Mathematical tests on
the key's parameters are then done in ecc_is_pubkey_valid_full eliminating
invalid keys.
The change is necessary since NIST P521 keys do not have keys with
coordinates that each fully require 'full' digits (= u64), unlike
NIST P192/256/384 that all require multiple 'full' digits.
Signed-off-by: Stefan Berger <[email protected]>
---
crypto/ecdsa.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
index c3748ddc9964..228f675ac2ed 100644
--- a/crypto/ecdsa.c
+++ b/crypto/ecdsa.c
@@ -230,7 +230,7 @@ static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsig
if (ret < 0)
return ret;
- if (keylen < 1 || (((keylen - 1) >> 1) % sizeof(u64)) != 0)
+ if (keylen < 1 || ((keylen - 1) & 1) != 0)
return -EINVAL;
/* we only accept uncompressed format indicated by '4' */
if (d[0] != 4)
@@ -239,7 +239,7 @@ static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsig
keylen--;
digitlen = keylen >> 1;
- ndigits = digitlen / sizeof(u64);
+ ndigits = DIV_ROUND_UP(digitlen, sizeof(u64));
if (ndigits != ctx->curve->g.ndigits)
return -EINVAL;
--
2.43.0