Add Elliptic Curve Russian Digital Signature Algorithm (GOST R
34.10-2012, RFC 7091, ISO/IEC 14888-3) is one of the Russian (and since
2018 the CIS countries) cryptographic standard algorithms (called GOST
algorithms). Only signature verification is supported, with intent to be
used in the IMA.

Summary of the changes:

* crypto/Kconfig:
- EC-RDSA is added into Public-key cryptography section.

* crypto/Makefile:
- ecrdsa objects are added.

* crypto/asymmetric_keys/x509_cert_parser.c:
- Recognize EC-RDSA and Streebog OIDs.

* include/linux/oid_registry.h:
- EC-RDSA OIDs are added to the enum. Also, a two currently not
implemented curve OIDs are added for possible extension later (to
not change numbering and grouping).

* crypto/ecc.c:
- Kenneth MacKay copyright date is updated to 2014, because
vli_mmod_slow, ecc_point_add, ecc_point_mult_shamir are based on his
code from micro-ecc.
- Functions needed for ecrdsa are EXPORT_SYMBOL'ed.
- New functions:
vli_is_negative - helper to determine sign of vli;
vli_from_be64 - unpack big-endian array into vli (used for
a signature);
vli_from_le64 - unpack little-endian array into vli (used for
a public key);
vli_uadd, vli_usub - add/sub u64 value to/from vli (used for
increment/decrement);
mul_64_64 - optimized to use __int128 where appropriate, this speeds
up point multiplication (and as a consequence signature
verification) by the factor of 1.5-2;
vli_umult - multiply vli by a small value (speeds up point
multiplication by another factor of 1.5-2, depending on vli sizes);
vli_mmod_special - module reduction for some form of Pseudo-Mersenne
primes (used for the curves A);
vli_mmod_special2 - module reduction for another form of
Pseudo-Mersenne primes (used for the curves B);
vli_mmod_barrett - module reduction using pre-computed value (used
for the curve C);
vli_mmod_slow - more general module reduction which is much slower
(used when the modulus is subgroup order);
vli_mod_mult_slow - modular multiplication;
ecc_point_add - add two points;
ecc_point_mult_shamir - add two points multiplied by scalars in one
combined multiplication (this gives speed up by another factor 2 in
compare to two separate multiplications).
ecc_is_pubkey_valid_partial - additional samity check is added.
- Updated vli_mmod_fast with non-strict heuristic to call optimal
module reduction function depending on the prime value;
- All computations for the previously defined (two NIST) curves should
not unaffected.

* crypto/ecc.h:
- Newly exported functions are documented.

* crypto/ecrdsa_defs.h
- Five curves are defined.

* crypto/ecrdsa.c:
- Signature verification is implemented.

* crypto/ecrdsa_params.asn1, crypto/ecrdsa_pub_key.asn1:
- Templates for BER decoder for EC-RDSA parameters and public key.

Cc: linux-integrity@vger.kernel.org
Signed-off-by: Vitaly Chikunov
Signed-off-by: Herbert Xu