Commit 7e8dec91 authored by Dmitry Kasatkin's avatar Dmitry Kasatkin
Browse files

crypto: GnuPG based MPI lib - additional sources (part 4) 



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.

This code is unnecessary for RSA digital signature verification,
but for completeness it is included here and can be compiled,
if CONFIG_MPILIB_EXTRA is enabled.

Signed-off-by: default avatarDmitry Kasatkin <dmitry.kasatkin@intel.com>
parent d9c46b18

lib/Kconfig

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Original line number Diff line number Diff line
@@ -283,4 +283,14 @@ config MPILIB 
	  It is used to implement RSA digital signature verification,

	  which is used by IMA/EVM digital signature extension.



config MPILIB_EXTRA

	bool "Multiprecision maths library - additional sources"

	depends on MPILIB

	help

	  Multiprecision maths library from GnuPG.

	  It is used to implement RSA digital signature verification,

	  which is used by IMA/EVM digital signature extension.

	  This code in unnecessary for RSA digital signature verification,

	  and can be compiled if needed.



endmenu

lib/mpi/Makefile

+11 −0
Original line number Diff line number Diff line
@@ -19,3 +19,14 @@ mpi-y = \ 
	mpih-mul.o			\

	mpi-pow.o			\

	mpiutil.o



mpi-$(CONFIG_MPILIB_EXTRA) += \

	mpi-add.o			\

	mpi-div.o			\

	mpi-cmp.o			\

	mpi-gcd.o			\

	mpi-inline.o			\

	mpi-inv.o			\

	mpi-mpow.o			\

	mpi-mul.o			\

	mpi-scan.o

lib/mpi/generic_mpi-asm-defs.h

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/* This file defines some basic constants for the MPI machinery.  We

 * need to define the types on a per-CPU basis, so it is done with

 * this file here.  */

#define BYTES_PER_MPI_LIMB  (SIZEOF_UNSIGNED_LONG)

lib/mpi/mpi-add.c

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Original line number Diff line number Diff line 
/* mpi-add.c  -  MPI functions

 *	Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.

 *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.

 *

 * This file is part of GnuPG.

 *

 * 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.

 */



#include "mpi-internal.h"



/****************

 * Add the unsigned integer V to the mpi-integer U and store the

 * result in W. U and V may be the same.

 */

int mpi_add_ui(MPI w, const MPI u, unsigned long v)

{

	mpi_ptr_t wp, up;

	mpi_size_t usize, wsize;

	int usign, wsign;



	usize = u->nlimbs;

	usign = u->sign;

	wsign = 0;



	/* If not space for W (and possible carry), increase space.  */

	wsize = usize + 1;

	if (w->alloced < wsize)

		if (mpi_resize(w, wsize) < 0)

			return -ENOMEM;



	/* These must be after realloc (U may be the same as W).  */

	up = u->d;

	wp = w->d;



	if (!usize) {		/* simple */

		wp[0] = v;

		wsize = v ? 1 : 0;

	} else if (!usign) {	/* mpi is not negative */

		mpi_limb_t cy;

		cy = mpihelp_add_1(wp, up, usize, v);

		wp[usize] = cy;

		wsize = usize + cy;

	} else {		/* The signs are different.  Need exact comparison to determine

				 * which operand to subtract from which.  */

		if (usize == 1 && up[0] < v) {

			wp[0] = v - up[0];

			wsize = 1;

		} else {

			mpihelp_sub_1(wp, up, usize, v);

			/* Size can decrease with at most one limb. */

			wsize = usize - (wp[usize - 1] == 0);

			wsign = 1;

		}

	}



	w->nlimbs = wsize;

	w->sign = wsign;

	return 0;

}



int mpi_add(MPI w, MPI u, MPI v)

{

	mpi_ptr_t wp, up, vp;

	mpi_size_t usize, vsize, wsize;

	int usign, vsign, wsign;



	if (u->nlimbs < v->nlimbs) {	/* Swap U and V. */

		usize = v->nlimbs;

		usign = v->sign;

		vsize = u->nlimbs;

		vsign = u->sign;

		wsize = usize + 1;

		if (RESIZE_IF_NEEDED(w, wsize) < 0)

			return -ENOMEM;

		/* These must be after realloc (u or v may be the same as w).  */

		up = v->d;

		vp = u->d;

	} else {

		usize = u->nlimbs;

		usign = u->sign;

		vsize = v->nlimbs;

		vsign = v->sign;

		wsize = usize + 1;

		if (RESIZE_IF_NEEDED(w, wsize) < 0)

			return -ENOMEM;

		/* These must be after realloc (u or v may be the same as w).  */

		up = u->d;

		vp = v->d;

	}

	wp = w->d;

	wsign = 0;



	if (!vsize) {		/* simple */

		MPN_COPY(wp, up, usize);

		wsize = usize;

		wsign = usign;

	} else if (usign != vsign) {	/* different sign */

		/* This test is right since USIZE >= VSIZE */

		if (usize != vsize) {

			mpihelp_sub(wp, up, usize, vp, vsize);

			wsize = usize;

			MPN_NORMALIZE(wp, wsize);

			wsign = usign;

		} else if (mpihelp_cmp(up, vp, usize) < 0) {

			mpihelp_sub_n(wp, vp, up, usize);

			wsize = usize;

			MPN_NORMALIZE(wp, wsize);

			if (!usign)

				wsign = 1;

		} else {

			mpihelp_sub_n(wp, up, vp, usize);

			wsize = usize;

			MPN_NORMALIZE(wp, wsize);

			if (usign)

				wsign = 1;

		}

	} else {		/* U and V have same sign. Add them. */

		mpi_limb_t cy = mpihelp_add(wp, up, usize, vp, vsize);

		wp[usize] = cy;

		wsize = usize + cy;

		if (usign)

			wsign = 1;

	}



	w->nlimbs = wsize;

	w->sign = wsign;

	return 0;

}



/****************

 * Subtract the unsigned integer V from the mpi-integer U and store the

 * result in W.

 */

int mpi_sub_ui(MPI w, MPI u, unsigned long v)

{

	mpi_ptr_t wp, up;

	mpi_size_t usize, wsize;

	int usign, wsign;



	usize = u->nlimbs;

	usign = u->sign;

	wsign = 0;



	/* If not space for W (and possible carry), increase space.  */

	wsize = usize + 1;

	if (w->alloced < wsize)

		if (mpi_resize(w, wsize) < 0)

			return -ENOMEM;



	/* These must be after realloc (U may be the same as W).  */

	up = u->d;

	wp = w->d;



	if (!usize) {		/* simple */

		wp[0] = v;

		wsize = v ? 1 : 0;

		wsign = 1;

	} else if (usign) {	/* mpi and v are negative */

		mpi_limb_t cy;

		cy = mpihelp_add_1(wp, up, usize, v);

		wp[usize] = cy;

		wsize = usize + cy;

	} else {		/* The signs are different.  Need exact comparison to determine

				 * which operand to subtract from which.  */

		if (usize == 1 && up[0] < v) {

			wp[0] = v - up[0];

			wsize = 1;

			wsign = 1;

		} else {

			mpihelp_sub_1(wp, up, usize, v);

			/* Size can decrease with at most one limb. */

			wsize = usize - (wp[usize - 1] == 0);

		}

	}



	w->nlimbs = wsize;

	w->sign = wsign;

	return 0;

}



int mpi_sub(MPI w, MPI u, MPI v)

{

	int rc;



	if (w == v) {

		MPI vv;

		if (mpi_copy(&vv, v) < 0)

			return -ENOMEM;

		vv->sign = !vv->sign;

		rc = mpi_add(w, u, vv);

		mpi_free(vv);

	} else {

		/* fixme: this is not thread-save (we temp. modify v) */

		v->sign = !v->sign;

		rc = mpi_add(w, u, v);

		v->sign = !v->sign;

	}

	return rc;

}



int mpi_addm(MPI w, MPI u, MPI v, MPI m)

{

	if (mpi_add(w, u, v) < 0 || mpi_fdiv_r(w, w, m) < 0)

		return -ENOMEM;

	return 0;

}



int mpi_subm(MPI w, MPI u, MPI v, MPI m)

{

	if (mpi_sub(w, u, v) < 0 || mpi_fdiv_r(w, w, m) < 0)

		return -ENOMEM;

	return 0;

}

lib/mpi/mpi-cmp.c

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+68 −0
Original line number Diff line number Diff line 
/* mpi-cmp.c  -  MPI functions

 * Copyright (C) 1998, 1999 Free Software Foundation, Inc.

 *

 * This file is part of GnuPG.

 *

 * 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

 */



#include "mpi-internal.h"



int mpi_cmp_ui(MPI u, unsigned long v)

{

	mpi_limb_t limb = v;



	mpi_normalize(u);

	if (!u->nlimbs && !limb)

		return 0;

	if (u->sign)

		return -1;

	if (u->nlimbs > 1)

		return 1;



	if (u->d[0] == limb)

		return 0;

	else if (u->d[0] > limb)

		return 1;

	else

		return -1;

}



int mpi_cmp(MPI u, MPI v)

{

	mpi_size_t usize, vsize;

	int cmp;



	mpi_normalize(u);

	mpi_normalize(v);

	usize = u->nlimbs;

	vsize = v->nlimbs;

	if (!u->sign && v->sign)

		return 1;

	if (u->sign && !v->sign)

		return -1;

	if (usize != vsize && !u->sign && !v->sign)

		return usize - vsize;

	if (usize != vsize && u->sign && v->sign)

		return vsize + usize;

	if (!usize)

		return 0;

	cmp = mpihelp_cmp(u->d, v->d, usize);

	if (!cmp)

		return 0;

	if ((cmp < 0 ? 1 : 0) == (u->sign ? 1 : 0))

		return 1;

	return -1;

}

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