crypto: ecdh - Initialize ctx->private_key in proper byte order

The private key in ctx->private_key is currently initialized in reverse
byte order in ecdh_set_secret and whenever the key is needed in proper
byte order the variable priv is introduced and the bytes from
ctx->private_key are copied into priv while being byte-swapped
(ecc_swap_digits). To get rid of the unnecessary byte swapping initialize
ctx->private_key in proper byte order and clean up all functions that were
previously using priv or were called with ctx->private_key:

- ecc_gen_privkey: Directly initialize the passed ctx->private_key with
  random bytes filling all the digits of the private key. Get rid of the
  priv variable. This function only has ecdh_set_secret as a caller to
  create NIST P192/256/384 private keys.

- crypto_ecdh_shared_secret: Called only from ecdh_compute_value with
  ctx->private_key. Get rid of the priv variable and work with the passed
  private_key directly.

- ecc_make_pub_key: Called only from ecdh_compute_value with
  ctx->private_key. Get rid of the priv variable and work with the passed
  private_key directly.

Cc: Salvatore Benedetto <salvatore.benedetto@intel.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/crypto/internal/ecc.h b/include/crypto/internal/ecc.h
index 4e2f5f938e91..7ca1f463d1ec 100644
--- a/include/crypto/internal/ecc.h
+++ b/include/crypto/internal/ecc.h
@@ -103,7 +103,8 @@ int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
  * Returns 0 if the private key was generated successfully, a negative value
  * if an error occurred.
  */
-int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey);
+int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits,
+		    u64 *private_key);
 
 /**
  * ecc_make_pub_key() - Compute an ECC public key