lib/mpi: fix spelling mistakes

Fix some spelling mistakes in comments:
flaged ==> flagged
bufer ==> buffer
multipler ==> multiplier
MULTIPLER ==> MULTIPLIER
leaset ==> least
chnage ==> change

Link: https://lkml.kernel.org/r/20210604074401.12198-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/mpi: Introduce ec implementation to MPI library

The implementation of EC is introduced from libgcrypt as the
basic algorithm of elliptic curve, which can be more perfectly
integrated with MPI implementation.
Some other algorithms will be developed based on mpi ecc, such as SM2.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Tested-by: Xufeng Zhang <yunbo.xufeng@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

lib/mpi: Extend the MPI library

Expand the mpi library based on libgcrypt, and the ECC algorithm of
mpi based on libgcrypt requires these functions.
Some other algorithms will be developed based on mpi ecc, such as SM2.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Tested-by: Xufeng Zhang <yunbo.xufeng@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

lib/mpi: Add mpi_sub_ui()

Add mpi_sub_ui() based on Gnu MP mpz_sub_ui() function from file
mpz/aors_ui.h[1] from change id 510b83519d1c adapting the code to the
kernel's data structures, helper functions and coding style and also
removing the defines used to produce mpz_sub_ui() and mpz_add_ui()
from the same code.

[1] https://gmplib.org/repo/gmp-6.2/file/510b83519d1c/mpz/aors.h

Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 26

Based on 1 normalized pattern(s):

gnupg is free software you can redistribute it and or modify it
under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version gnupg is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details you should have
received a copy of the gnu general public license along with this
program if not write to the free software foundation inc 59 temple
place suite 330 boston ma 02111 1307 usa note this code is heavily
based on the gnu mp library actually it s the same code with only
minor changes in the way the data is stored this is to support the
abstraction of an optional secure memory allocation which may be
used to avoid revealing of sensitive data due to paging etc the gnu
mp library itself is published under the lgpl however i decided to
publish this code under the plain gpl

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 14 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170856.639982569@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/mpi: headers cleanup

MPI headers contain definitions for huge number of non-existing
functions.

Most part of these functions was removed in 2012 by Dmitry Kasatkin
- 7cf4206a99d1 ("Remove unused code from MPI library")
- 9e235dcaf4f6 ("Revert "crypto: GnuPG based MPI lib - additional ...")
- bc95eeadf5c6 ("lib/mpi: removed unused functions")
however headers wwere not updated properly.

Also I deleted some unused macros.

Link: http://lkml.kernel.org/r/fb2fc1ef-1185-f0a3-d8d0-173d2f97bbaf@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

crypto: rsa - Generate fixed-length output

Every implementation of RSA that we have naturally generates
output with leading zeroes. The one and only user of RSA,
pkcs1pad wants to have those leading zeroes in place, in fact
because they are currently absent it has to write those zeroes
itself.

So we shouldn't be stripping leading zeroes in the first place.
In fact this patch makes rsa-generic produce output with fixed
length so that pkcs1pad does not need to do any extra work.

This patch also changes DH to use the new interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

lib/mpi: purge mpi_set_buffer()

mpi_set_buffer() has no in-tree users and similar functionality is provided
by mpi_read_raw_data().

Remove mpi_set_buffer().

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

lib/mpi: clean unused SHA1_DIGEST_LENGTH

The define SHA1_DIGEST_LENGTH is not used anywhere, so remove it.

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

lib/mpi: Add mpi sgl helpers

Add mpi_read_raw_from_sgl and mpi_write_to_sgl helpers.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

MPILIB: add mpi_read_buf() and mpi_get_size() helpers

Added a mpi_read_buf() helper function to export MPI to a buf provided by
the user, and a mpi_get_size() helper, that tells the user how big the buf is.
Changed mpi_free to use kzfree instead of kfree because it is used to free
crypto keys.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

MPILIB: Provide a function to read raw data into an MPI

Provide a function to read raw data of a predetermined size into an MPI rather
than expecting the size to be encoded within the data. The data is assumed to
represent an unsigned integer, and the resulting MPI will be positive.

The function looks like this:

MPI mpi_read_raw_data(const void *, size_t);

This is useful for reading ASN.1 integer primitives where the length is encoded
in the ASN.1 metadata.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lib/mpi: replaced MPI_NULL with normal NULL

MPI_NULL is replaced with normal NULL.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Reviewed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

crypto: GnuPG based MPI lib - header files (part 2)

Adds the multi-precision-integer maths library which was originally taken
from GnuPG and ported to the kernel by (among others) David Howells.
This version is taken from Fedora kernel 2.6.32-71.14.1.el6.
The difference is that checkpatch reported errors and warnings have been fixed.

This library is used to implemenet RSA digital signature verification
used in IMA/EVM integrity protection subsystem.

Due to patch size limitation, the patch is divided into 4 parts.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>