[openssl-gost] [gost-engine/engine] f3e7c2: ec: Use BN_{CTX_,}secure_new memory API for priv keys

[Vitalio <noreply@github.com>]

  Branch: refs/heads/master
  Home:   https://github.com/gost-engine/engine
  Commit: f3e7c24d4733bb1c096e43345602d3258e994e3c
      https://github.com/gost-engine/engine/commit/f3e7c24d4733bb1c096e43345602d3258e994e3c
  Author: Vitaly Chikunov <vt@altlinux.org>
  Date:   2020-02-26 (Wed, 26 Feb 2020)

  Changed paths:
    M gost_ameth.c
    M gost_ec_keyx.c
    M gost_ec_sign.c
    M gost_lcl.h

  Log Message:
  -----------
  ec: Use BN_{CTX_,}secure_new memory API for priv keys

OpenSSL suggests to use (and internally itself uses)
`BN_{CTX_,}secure_new' primitives to work with private keys.

These are using `OPENSSL_secure_malloc' et al. calls, which use
special 'secure heap' memory.

Along, optimize out `hashsum2bn' with `BN_lebin2bn'.


  Commit: dd6e77bbda3347148139111b9433ab4f6bd1f46c
      https://github.com/gost-engine/engine/commit/dd6e77bbda3347148139111b9433ab4f6bd1f46c
  Author: Vitaly Chikunov <vt@altlinux.org>
  Date:   2020-02-26 (Wed, 26 Feb 2020)

  Changed paths:
    M gost89.c
    M gost_crypt.c
    M gost_grasshopper_cipher.c

  Log Message:
  -----------
  Replace RAND_bytes with RAND_priv_bytes

`RAND_priv_bytes' is supposed to be used for private data.


  Commit: 2883c9c20b26688f648fc14db1637890f96cab35
      https://github.com/gost-engine/engine/commit/2883c9c20b26688f648fc14db1637890f96cab35
  Author: Vitaly Chikunov <vt@altlinux.org>
  Date:   2020-02-26 (Wed, 26 Feb 2020)

  Changed paths:
    M gost_ec_keyx.c

  Log Message:
  -----------
  keyx: Add OPENSSL_cleanse for internal buffers

Only stack buffers are considered.


Compare: https://github.com/gost-engine/engine/compare/77551c5d97fe...2883c9c20b26