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From: Ard Biesheuvel <ardb@kernel.org>
To: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Cc: "Herbert Xu" <herbert@gondor.apana.org.au>,
	"Stephan Müller" <smueller@chronox.de>,
	"Linux Crypto Mailing List" <linux-crypto@vger.kernel.org>,
	"Tianjia Zhang" <tianjia.zhang@linux.alibaba.com>,
	"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
	nhorman@redhat.com, simo@redhat.com
Subject: Re: [PATCH v2 2/5] lib/mpi: Add mpi_sub_ui()
Date: Thu, 16 Jul 2020 16:09:39 +0300
Message-ID: <CAMj1kXHBmgaQKDQoVd-wN0JpKunE53QRg6uQ=3fRZmpNw=drYg@mail.gmail.com> (raw)
In-Reply-To: <20200716125002.oxr7yyeehz74mgq4@valinor>

On Thu, 16 Jul 2020 at 15:50, Marcelo Henrique Cerri
<marcelo.cerri@canonical.com> wrote:
>
> No. The code is really based on Gnu MP. I used the header from
> lib/mpi/mpi-pow.c as reference and that's source of the mention to
> GnuPG that went unnoticed by me.
>

So where did the file lib/mpi/mpi-sub-ui.c come from? From GnuPG or
from GnuMP? Did you modify the license statement? Because as proposed,
this patch clearly is not acceptable from GPL compliance  point of
view.



> You can find the original Gnu MP source that I used as reference in
> the file gmp-6.2.0/mpz/aors_ui.h from:
>
> https://gmplib.org/download/gmp/gmp-6.2.0.tar.lz
>
> I'm pasting the contents of gmp-6.2.0/mpz/aors_ui.h below for
> reference. Do you think we should use or adapt the original header
> instead?
>
> That said, assuming the patch set submitted by Tianjia is updated to
> ensure that mpi_sub_ui() and other functions are returning allocation
> errors, we could drop this patch in favor of that patch set that is
> more extensive and also provides an implementation to mpi_sub_ui().
>
>
> --->8---
> /* mpz_add_ui, mpz_sub_ui -- Add or subtract an mpz_t and an unsigned
>    one-word integer.
>
> Copyright 1991, 1993, 1994, 1996, 1999-2002, 2004, 2012, 2013, 2015
> Free Software Foundation, Inc.
>
> This file is part of the GNU MP Library.
>
> The GNU MP Library is free software; you can redistribute it and/or modify
> it under the terms of either:
>
>   * the GNU Lesser General Public License as published by the Free
>     Software Foundation; either version 3 of the License, or (at your
>     option) any later version.
>
> or
>
>   * 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.
>
> or both in parallel, as here.
>
> The GNU MP Library 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 copies of the GNU General Public License and the
> GNU Lesser General Public License along with the GNU MP Library.  If not,
> see https://www.gnu.org/licenses/.  */
>
> #include "gmp-impl.h"
>
>
> #ifdef OPERATION_add_ui
> #define FUNCTION          mpz_add_ui
> #define FUNCTION2         mpz_add
> #define VARIATION_CMP     >=
> #define VARIATION_NEG
> #define VARIATION_UNNEG   -
> #endif
>
> #ifdef OPERATION_sub_ui
> #define FUNCTION          mpz_sub_ui
> #define FUNCTION2         mpz_sub
> #define VARIATION_CMP     <
> #define VARIATION_NEG     -
> #define VARIATION_UNNEG
> #endif
>
> #ifndef FUNCTION
> Error, need OPERATION_add_ui or OPERATION_sub_ui
> #endif
>
>
> void
> FUNCTION (mpz_ptr w, mpz_srcptr u, unsigned long int vval)
> {
>   mp_srcptr up;
>   mp_ptr wp;
>   mp_size_t usize, wsize;
>   mp_size_t abs_usize;
>
> #if BITS_PER_ULONG > GMP_NUMB_BITS  /* avoid warnings about shift amount */
>   if (vval > GMP_NUMB_MAX)
>     {
>       mpz_t v;
>       mp_limb_t vl[2];
>       PTR(v) = vl;
>       vl[0] = vval & GMP_NUMB_MASK;
>       vl[1] = vval >> GMP_NUMB_BITS;
>       SIZ(v) = 2;
>       FUNCTION2 (w, u, v);
>       return;
>     }
> #endif
>
>   usize = SIZ (u);
>   if (usize == 0)
>     {
>       MPZ_NEWALLOC (w, 1)[0] = vval;
>       SIZ (w) = VARIATION_NEG (vval != 0);
>       return;
>     }
>
>   abs_usize = ABS (usize);
>
>   /* If not space for W (and possible carry), increase space.  */
>   wp = MPZ_REALLOC (w, abs_usize + 1);
>
>   /* These must be after realloc (U may be the same as W).  */
>   up = PTR (u);
>
>   if (usize VARIATION_CMP 0)
>     {
>       mp_limb_t cy;
>       cy = mpn_add_1 (wp, up, abs_usize, (mp_limb_t) vval);
>       wp[abs_usize] = cy;
>       wsize = VARIATION_NEG (abs_usize + cy);
>     }
>   else
>     {
>       /* The signs are different.  Need exact comparison to determine
>          which operand to subtract from which.  */
>       if (abs_usize == 1 && up[0] < vval)
>         {
>           wp[0] = vval - up[0];
>           wsize = VARIATION_NEG 1;
>         }
>       else
>         {
>           mpn_sub_1 (wp, up, abs_usize, (mp_limb_t) vval);
>           /* Size can decrease with at most one limb.  */
>           wsize = VARIATION_UNNEG (abs_usize - (wp[abs_usize - 1] == 0));
>         }
>     }
>
>   SIZ (w) = wsize;
> }
> --->*---
>
>
>
> On Thu, Jul 16, 2020 at 11:41:17AM +0300, Ard Biesheuvel wrote:
> > On Thu, 16 Jul 2020 at 10:30, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> > >
> > > On Sun, Jul 12, 2020 at 06:39:54PM +0200, Stephan Müller wrote:
> > > >
> > > > 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.
> > > > + */
> > >
> > > Hmm, you said that this code is from GNU MP.  But this notice clearly
> > > says that it's part of GnuPG and is under GPL.  Though it doesn't
> > > clarify what version of GPL it is.  Can you please clarify this with
> > > the author?
> > >
> >
> > GnuPG was relicensed under GPLv3 in ~2007, IIRC, so given the
> > copyright years and the explicit statements that the file is part of
> > GnuPG and not under the original LGPL license, there is no way we can
> > take this code under the kernel's GPLv2 license.
>
> --
> Regards,
> Marcelo
>

  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
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 [this message]
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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