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From: Ard Biesheuvel <ardb@kernel.org>
To: "Stephan Müller" <smueller@chronox.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
	Marcelo Cerri <marcelo.cerri@canonical.com>,
	Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Subject: Re: [PATCH 2/3] lib/mpi: Add mpi_sub_ui()
Date: Fri, 10 Jul 2020 17:42:39 +0300
Message-ID: <CAMj1kXFjzHphXUt7Hesj_EAOJmar9Du1U6YM9X+davMOB6tcng@mail.gmail.com> (raw)
In-Reply-To: <4577235.31r3eYUQgx@positron.chronox.de>

On Fri, 10 Jul 2020 at 13:16, Stephan Müller <smueller@chronox.de> wrote:
>
> Add mpi_sub_ui() based on Gnu PG mpz_sub_ui() from mpz/aors_ui.h
> adapting the code to the kernel's structures and coding style and also
> removing the defines used to produce mpz_sub_ui() and mpz_add_ui()
> from the same code.
>

Isn't GnuPG GPLv3 ?


> Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
> Signed-off-by: Stephan Mueller <smueller@chronox.de>
> ---
>  include/linux/mpi.h  |  3 +++
>  lib/mpi/Makefile     |  1 +
>  lib/mpi/mpi-sub-ui.c | 60 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 64 insertions(+)
>  create mode 100644 lib/mpi/mpi-sub-ui.c
>
> diff --git a/include/linux/mpi.h b/include/linux/mpi.h
> index 7bd6d8af0004..5d906dfbf3ed 100644
> --- a/include/linux/mpi.h
> +++ b/include/linux/mpi.h
> @@ -63,6 +63,9 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
>  int mpi_cmp_ui(MPI u, ulong v);
>  int mpi_cmp(MPI u, MPI v);
>
> +/*-- mpi-sub-ui.c --*/
> +int mpi_sub_ui(MPI w, MPI u, unsigned long vval);
> +
>  /*-- mpi-bit.c --*/
>  void mpi_normalize(MPI a);
>  unsigned mpi_get_nbits(MPI a);
> diff --git a/lib/mpi/Makefile b/lib/mpi/Makefile
> index d5874a7f5ff9..43b8fce14079 100644
> --- a/lib/mpi/Makefile
> +++ b/lib/mpi/Makefile
> @@ -16,6 +16,7 @@ mpi-y = \
>         mpicoder.o                      \
>         mpi-bit.o                       \
>         mpi-cmp.o                       \
> +       mpi-sub-ui.o                    \
>         mpih-cmp.o                      \
>         mpih-div.o                      \
>         mpih-mul.o                      \
> diff --git a/lib/mpi/mpi-sub-ui.c b/lib/mpi/mpi-sub-ui.c
> new file mode 100644
> index 000000000000..fa6b085bac36
> --- /dev/null
> +++ b/lib/mpi/mpi-sub-ui.c
> @@ -0,0 +1,60 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* mpi-sub-ui.c  -  MPI functions
> + *      Copyright 1991, 1993, 1994, 1996, 1999-2002, 2004, 2012, 2013, 2015
> + *      Free Software Foundation, Inc.
> + *
> + * This file is part of GnuPG.
> + *
> + * 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.
> + */
> +
> +#include "mpi-internal.h"
> +
> +int mpi_sub_ui(MPI w, MPI u, unsigned long vval)
> +{
> +       if (u->nlimbs == 0) {
> +               if (mpi_resize(w, 1) < 0)
> +                       return -ENOMEM;
> +               w->d[0] = vval;
> +               w->nlimbs = (vval != 0);
> +               w->sign = (vval != 0);
> +               return 0;
> +       }
> +
> +       /* If not space for W (and possible carry), increase space. */
> +       if (mpi_resize(w, u->nlimbs + 1))
> +               return -ENOMEM;
> +
> +       if (u->sign) {
> +               mpi_limb_t cy;
> +
> +               cy = mpihelp_add_1(w->d, u->d, u->nlimbs, (mpi_limb_t) vval);
> +               w->d[u->nlimbs] = cy;
> +               w->nlimbs = u->nlimbs + cy;
> +               w->sign = 1;
> +       } else {
> +               /* The signs are different.  Need exact comparison to determine
> +                * which operand to subtract from which.
> +                */
> +               if (u->nlimbs == 1 && u->d[0] < vval) {
> +                       w->d[0] = vval - u->d[0];
> +                       w->nlimbs = 1;
> +                       w->sign = 1;
> +               } else {
> +                       mpihelp_sub_1(w->d, u->d, u->nlimbs, (mpi_limb_t) vval);
> +                       /* Size can decrease with at most one limb. */
> +                       w->nlimbs = (u->nlimbs - (w->d[u->nlimbs - 1] == 0));
> +                       w->sign = 0;
> +               }
> +       }
> +
> +       mpi_normalize(w);
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(mpi_sub_ui);
> --
> 2.26.2
>
>
>
>

  reply index

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-10 10:09 [PATCH 0/3] DH: SP800-56A rev 3 compliant shared secret Stephan Müller
2020-07-10 10:10 ` [PATCH 1/3] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-10 10:10 ` [PATCH 2/3] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-10 14:42   ` Ard Biesheuvel [this message]
2020-07-10 15:10     ` Stephan Mueller
2020-07-10 10:15 ` [PATCH 3/3] crypto: DH - check validity of Z before export Stephan Müller
2020-07-12 16:38 ` [PATCH v2 0/5] DH: SP800-56A rev 3 compliant validation checks Stephan Müller
2020-07-12 16:39   ` [PATCH v2 1/5] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-12 18:02     ` Vitaly Chikunov
2020-07-15 13:17     ` Marcelo Henrique Cerri
2020-07-12 16:39   ` [PATCH v2 2/5] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-16  7:30     ` Herbert Xu
2020-07-16  8:41       ` Ard Biesheuvel
2020-07-16 12:50         ` Marcelo Henrique Cerri
2020-07-16 13:09           ` Ard Biesheuvel
2020-07-16 13:41             ` Marcelo Henrique Cerri
2020-07-16 13:53               ` Ard Biesheuvel
2020-07-16 14:23                 ` Marcelo Henrique Cerri
2020-07-16 14:37                   ` Ard Biesheuvel
2020-07-16 14:56                     ` Marcelo Henrique Cerri
2020-07-16 15:20                       ` Ard Biesheuvel
2020-07-12 16:40   ` [PATCH v2 3/5] crypto: DH - check validity of Z before export Stephan Müller
2020-07-15 13:17     ` Marcelo Henrique Cerri
2020-07-12 16:40   ` [PATCH v2 4/5] crypto: DH SP800-56A rev 3 local public key validation Stephan Müller
2020-07-15 13:18     ` Marcelo Henrique Cerri
2020-07-12 16:42   ` [PATCH v2 5/5] crypto: ECDH " Stephan Müller
2020-07-12 18:06     ` Vitaly Chikunov
2020-07-13  5:04       ` Stephan Mueller
2020-07-13  5:59         ` Vitaly Chikunov
2020-07-13  6:02           ` Stephan Müller
2020-07-15 13:19     ` Marcelo Henrique Cerri
2020-07-20 17:05   ` [PATCH v3 0/5] DH: SP800-56A rev 3 compliant validation checks Stephan Müller
2020-07-20 17:07     ` [PATCH v3 1/5] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-22 13:11       ` Vitaly Chikunov
2020-07-24 17:47       ` Neil Horman
2020-07-20 17:08     ` [PATCH v3 2/5] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-20 17:08     ` [PATCH v3 3/5] crypto: DH - check validity of Z before export Stephan Müller
2020-07-24 18:02       ` Neil Horman
2020-07-20 17:08     ` [PATCH v3 4/5] crypto: DH SP800-56A rev 3 local public key validation Stephan Müller
2020-07-20 17:09     ` [PATCH v3 5/5] crypto: ECDH " Stephan Müller
2020-07-21 11:35     ` [PATCH v3 0/5] DH: SP800-56A rev 3 compliant validation checks Marcelo Henrique Cerri
2020-07-31 13:29     ` Herbert Xu

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