Resguardo inicial

linux-7.2.3/lib/crypto/mpi/Makefile

@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# MPI multiprecision maths library (from gpg)
+#
+
+obj-$(CONFIG_MPILIB) = mpi.o
+
+mpi-y = \
+	generic_mpih-lshift.o		\
+	generic_mpih-mul1.o		\
+	generic_mpih-mul2.o		\
+	generic_mpih-mul3.o		\
+	generic_mpih-rshift.o		\
+	generic_mpih-sub1.o		\
+	generic_mpih-add1.o		\
+	mpicoder.o			\
+	mpi-add.o			\
+	mpi-bit.o			\
+	mpi-cmp.o			\
+	mpi-sub-ui.o			\
+	mpi-div.o			\
+	mpi-mod.o			\
+	mpi-mul.o			\
+	mpih-cmp.o			\
+	mpih-div.o			\
+	mpih-mul.o			\
+	mpi-pow.o			\
+	mpiutil.o

linux-7.2.3/lib/crypto/mpi/generic_mpih-add1.c

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-add_1.c  -  MPI helper functions
+ * Copyright (C) 1994, 1996, 1997, 1998,
+ *               2000 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"
+#include "longlong.h"
+
+mpi_limb_t
+mpihelp_add_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+	      mpi_ptr_t s2_ptr, mpi_size_t size)
+{
+	mpi_limb_t x, y, cy;
+	mpi_size_t j;
+
+	/* The loop counter and index J goes from -SIZE to -1.  This way
+	   the loop becomes faster.  */
+	j = -size;
+
+	/* Offset the base pointers to compensate for the negative indices. */
+	s1_ptr -= j;
+	s2_ptr -= j;
+	res_ptr -= j;
+
+	cy = 0;
+	do {
+		y = s2_ptr[j];
+		x = s1_ptr[j];
+		y += cy;	/* add previous carry to one addend */
+		cy = y < cy;	/* get out carry from that addition */
+		y += x;		/* add other addend */
+		cy += y < x;	/* get out carry from that add, combine */
+		res_ptr[j] = y;
+	} while (++j);
+
+	return cy;
+}

linux-7.2.3/lib/crypto/mpi/generic_mpih-lshift.c

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-lshift.c  -	MPI helper functions
+ * Copyright (C) 1994, 1996, 1998, 2001 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"
+
+/* Shift U (pointed to by UP and USIZE digits long) CNT bits to the left
+ * and store the USIZE least significant digits of the result at WP.
+ * Return the bits shifted out from the most significant digit.
+ *
+ * Argument constraints:
+ * 1. 0 < CNT < BITS_PER_MP_LIMB
+ * 2. If the result is to be written over the input, WP must be >= UP.
+ */
+
+mpi_limb_t
+mpihelp_lshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize, unsigned int cnt)
+{
+	mpi_limb_t high_limb, low_limb;
+	unsigned sh_1, sh_2;
+	mpi_size_t i;
+	mpi_limb_t retval;
+
+	sh_1 = cnt;
+	wp += 1;
+	sh_2 = BITS_PER_MPI_LIMB - sh_1;
+	i = usize - 1;
+	low_limb = up[i];
+	retval = low_limb >> sh_2;
+	high_limb = low_limb;
+	while (--i >= 0) {
+		low_limb = up[i];
+		wp[i] = (high_limb << sh_1) | (low_limb >> sh_2);
+		high_limb = low_limb;
+	}
+	wp[i] = high_limb << sh_1;
+
+	return retval;
+}

linux-7.2.3/lib/crypto/mpi/generic_mpih-mul1.c

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-mul_1.c  -  MPI helper functions
+ * Copyright (C) 1994, 1996, 1997, 1998, 2001 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"
+#include "longlong.h"
+
+mpi_limb_t
+mpihelp_mul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+	      mpi_limb_t s2_limb)
+{
+	mpi_limb_t cy_limb;
+	mpi_size_t j;
+	mpi_limb_t prod_high, prod_low;
+
+	/* The loop counter and index J goes from -S1_SIZE to -1.  This way
+	 * the loop becomes faster.  */
+	j = -s1_size;
+
+	/* Offset the base pointers to compensate for the negative indices.  */
+	s1_ptr -= j;
+	res_ptr -= j;
+
+	cy_limb = 0;
+	do {
+		umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
+		prod_low += cy_limb;
+		cy_limb = (prod_low < cy_limb ? 1 : 0) + prod_high;
+		res_ptr[j] = prod_low;
+	} while (++j);
+
+	return cy_limb;
+}

linux-7.2.3/lib/crypto/mpi/generic_mpih-mul2.c

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-mul_2.c  -  MPI helper functions
+ * Copyright (C) 1994, 1996, 1997, 1998, 2001 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"
+#include "longlong.h"
+
+mpi_limb_t
+mpihelp_addmul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+		 mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+	mpi_limb_t cy_limb;
+	mpi_size_t j;
+	mpi_limb_t prod_high, prod_low;
+	mpi_limb_t x;
+
+	/* The loop counter and index J goes from -SIZE to -1.  This way
+	 * the loop becomes faster.  */
+	j = -s1_size;
+	res_ptr -= j;
+	s1_ptr -= j;
+
+	cy_limb = 0;
+	do {
+		umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
+
+		prod_low += cy_limb;
+		cy_limb = (prod_low < cy_limb ? 1 : 0) + prod_high;
+
+		x = res_ptr[j];
+		prod_low = x + prod_low;
+		cy_limb += prod_low < x ? 1 : 0;
+		res_ptr[j] = prod_low;
+	} while (++j);
+	return cy_limb;
+}

linux-7.2.3/lib/crypto/mpi/generic_mpih-mul3.c

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-mul_3.c  -  MPI helper functions
+ * Copyright (C) 1994, 1996, 1997, 1998, 2001 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"
+#include "longlong.h"
+
+mpi_limb_t
+mpihelp_submul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+		 mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+	mpi_limb_t cy_limb;
+	mpi_size_t j;
+	mpi_limb_t prod_high, prod_low;
+	mpi_limb_t x;
+
+	/* The loop counter and index J goes from -SIZE to -1.  This way
+	 * the loop becomes faster.  */
+	j = -s1_size;
+	res_ptr -= j;
+	s1_ptr -= j;
+
+	cy_limb = 0;
+	do {
+		umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
+
+		prod_low += cy_limb;
+		cy_limb = (prod_low < cy_limb ? 1 : 0) + prod_high;
+
+		x = res_ptr[j];
+		prod_low = x - prod_low;
+		cy_limb += prod_low > x ? 1 : 0;
+		res_ptr[j] = prod_low;
+	} while (++j);
+
+	return cy_limb;
+}

linux-7.2.3/lib/crypto/mpi/generic_mpih-rshift.c

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpih-rshift.c  -  MPI helper functions
+ * Copyright (C) 1994, 1996, 1998, 1999,
+ *               2000, 2001 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"
+
+/* Shift U (pointed to by UP and USIZE limbs long) CNT bits to the right
+ * and store the USIZE least significant limbs of the result at WP.
+ * The bits shifted out to the right are returned.
+ *
+ * Argument constraints:
+ * 1. 0 < CNT < BITS_PER_MP_LIMB
+ * 2. If the result is to be written over the input, WP must be <= UP.
+ */
+
+mpi_limb_t
+mpihelp_rshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize, unsigned cnt)
+{
+	mpi_limb_t high_limb, low_limb;
+	unsigned sh_1, sh_2;
+	mpi_size_t i;
+	mpi_limb_t retval;
+
+	sh_1 = cnt;
+	wp -= 1;
+	sh_2 = BITS_PER_MPI_LIMB - sh_1;
+	high_limb = up[0];
+	retval = high_limb << sh_2;
+	low_limb = high_limb;
+	for (i = 1; i < usize; i++) {
+		high_limb = up[i];
+		wp[i] = (low_limb >> sh_1) | (high_limb << sh_2);
+		low_limb = high_limb;
+	}
+	wp[i] = low_limb >> sh_1;
+
+	return retval;
+}

linux-7.2.3/lib/crypto/mpi/generic_mpih-sub1.c

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-add_2.c  -  MPI helper functions
+ * Copyright (C) 1994, 1996, 1997, 1998, 2001 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"
+#include "longlong.h"
+
+mpi_limb_t
+mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+	      mpi_ptr_t s2_ptr, mpi_size_t size)
+{
+	mpi_limb_t x, y, cy;
+	mpi_size_t j;
+
+	/* The loop counter and index J goes from -SIZE to -1.  This way
+	   the loop becomes faster.  */
+	j = -size;
+
+	/* Offset the base pointers to compensate for the negative indices.  */
+	s1_ptr -= j;
+	s2_ptr -= j;
+	res_ptr -= j;
+
+	cy = 0;
+	do {
+		y = s2_ptr[j];
+		x = s1_ptr[j];
+		y += cy;	/* add previous carry to subtrahend */
+		cy = y < cy;	/* get out carry from that addition */
+		y = x - y;	/* main subtract */
+		cy += y > x;	/* get out carry from the subtract, combine */
+		res_ptr[j] = y;
+	} while (++j);
+
+	return cy;
+}

linux-7.2.3/lib/crypto/mpi/mpi-add.c

@@ -0,0 +1,120 @@
+/* mpi-add.c  -  MPI functions
+ * Copyright (C) 1994, 1996, 1998, 2001, 2002,
+ *               2003 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * 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.
+ */
+
+#include <linux/export.h>
+
+#include "mpi-internal.h"
+
+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;
+	int err;
+
+	if (u->nlimbs < v->nlimbs) { /* Swap U and V. */
+		usize = v->nlimbs;
+		usign = v->sign;
+		vsize = u->nlimbs;
+		vsign = u->sign;
+		wsize = usize + 1;
+		err = RESIZE_IF_NEEDED(w, wsize);
+		if (err)
+			return err;
+		/* 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;
+		err = RESIZE_IF_NEEDED(w, wsize);
+		if (err)
+			return err;
+		/* 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;
+}
+EXPORT_SYMBOL_GPL(mpi_add);
+
+int mpi_sub(MPI w, MPI u, MPI v)
+{
+	int err;
+	MPI vv;
+
+	vv = mpi_copy(v);
+	if (!vv)
+		return -ENOMEM;
+
+	vv->sign = !vv->sign;
+	err = mpi_add(w, u, vv);
+	mpi_free(vv);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(mpi_sub);
+
+int mpi_addm(MPI w, MPI u, MPI v, MPI m)
+{
+	return mpi_add(w, u, v) ?:
+	       mpi_mod(w, w, m);
+}
+EXPORT_SYMBOL_GPL(mpi_addm);
+
+int mpi_subm(MPI w, MPI u, MPI v, MPI m)
+{
+	return mpi_sub(w, u, v) ?:
+	       mpi_mod(w, w, m);
+}
+EXPORT_SYMBOL_GPL(mpi_subm);

linux-7.2.3/lib/crypto/mpi/mpi-bit.c

@@ -0,0 +1,177 @@
+/* mpi-bit.c  -  MPI bit level 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 <linux/export.h>
+
+#include "mpi-internal.h"
+#include "longlong.h"
+
+#define A_LIMB_1 ((mpi_limb_t) 1)
+
+/****************
+ * Sometimes we have MSL (most significant limbs) which are 0;
+ * this is for some reasons not good, so this function removes them.
+ */
+void mpi_normalize(MPI a)
+{
+	for (; a->nlimbs && !a->d[a->nlimbs - 1]; a->nlimbs--)
+		;
+}
+
+/****************
+ * Return the number of bits in A.
+ */
+unsigned mpi_get_nbits(MPI a)
+{
+	unsigned n;
+
+	mpi_normalize(a);
+
+	if (a->nlimbs) {
+		mpi_limb_t alimb = a->d[a->nlimbs - 1];
+		if (alimb)
+			n = count_leading_zeros(alimb);
+		else
+			n = BITS_PER_MPI_LIMB;
+		n = BITS_PER_MPI_LIMB - n + (a->nlimbs - 1) * BITS_PER_MPI_LIMB;
+	} else
+		n = 0;
+	return n;
+}
+EXPORT_SYMBOL_GPL(mpi_get_nbits);
+
+/****************
+ * Test whether bit N is set.
+ */
+int mpi_test_bit(MPI a, unsigned int n)
+{
+	unsigned int limbno, bitno;
+	mpi_limb_t limb;
+
+	limbno = n / BITS_PER_MPI_LIMB;
+	bitno  = n % BITS_PER_MPI_LIMB;
+
+	if (limbno >= a->nlimbs)
+		return 0; /* too far left: this is a 0 */
+	limb = a->d[limbno];
+	return (limb & (A_LIMB_1 << bitno)) ? 1 : 0;
+}
+EXPORT_SYMBOL_GPL(mpi_test_bit);
+
+/****************
+ * Set bit N of A.
+ */
+int mpi_set_bit(MPI a, unsigned int n)
+{
+	unsigned int i, limbno, bitno;
+	int err;
+
+	limbno = n / BITS_PER_MPI_LIMB;
+	bitno  = n % BITS_PER_MPI_LIMB;
+
+	if (limbno >= a->nlimbs) {
+		for (i = a->nlimbs; i < a->alloced; i++)
+			a->d[i] = 0;
+		err = mpi_resize(a, limbno+1);
+		if (err)
+			return err;
+		a->nlimbs = limbno+1;
+	}
+	a->d[limbno] |= (A_LIMB_1<<bitno);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_set_bit);
+
+/*
+ * Shift A by N bits to the right.
+ */
+int mpi_rshift(MPI x, MPI a, unsigned int n)
+{
+	mpi_size_t xsize;
+	unsigned int i;
+	unsigned int nlimbs = (n/BITS_PER_MPI_LIMB);
+	unsigned int nbits = (n%BITS_PER_MPI_LIMB);
+	int err;
+
+	if (x == a) {
+		/* In-place operation.  */
+		if (nlimbs >= x->nlimbs) {
+			x->nlimbs = 0;
+			return 0;
+		}
+
+		if (nlimbs) {
+			for (i = 0; i < x->nlimbs - nlimbs; i++)
+				x->d[i] = x->d[i+nlimbs];
+			x->d[i] = 0;
+			x->nlimbs -= nlimbs;
+		}
+		if (x->nlimbs && nbits)
+			mpihelp_rshift(x->d, x->d, x->nlimbs, nbits);
+	} else if (nlimbs) {
+		/* Copy and shift by more or equal bits than in a limb. */
+		xsize = a->nlimbs;
+		x->sign = a->sign;
+		err = RESIZE_IF_NEEDED(x, xsize);
+		if (err)
+			return err;
+		x->nlimbs = xsize;
+		for (i = 0; i < a->nlimbs; i++)
+			x->d[i] = a->d[i];
+		x->nlimbs = i;
+
+		if (nlimbs >= x->nlimbs) {
+			x->nlimbs = 0;
+			return 0;
+		}
+
+		for (i = 0; i < x->nlimbs - nlimbs; i++)
+			x->d[i] = x->d[i+nlimbs];
+		x->d[i] = 0;
+		x->nlimbs -= nlimbs;
+
+		if (x->nlimbs && nbits)
+			mpihelp_rshift(x->d, x->d, x->nlimbs, nbits);
+	} else {
+		/* Copy and shift by less than bits in a limb.  */
+		xsize = a->nlimbs;
+		x->sign = a->sign;
+		err = RESIZE_IF_NEEDED(x, xsize);
+		if (err)
+			return err;
+		x->nlimbs = xsize;
+
+		if (xsize) {
+			if (nbits)
+				mpihelp_rshift(x->d, a->d, x->nlimbs, nbits);
+			else {
+				/* The rshift helper function is not specified for
+				 * NBITS==0, thus we do a plain copy here.
+				 */
+				for (i = 0; i < x->nlimbs; i++)
+					x->d[i] = a->d[i];
+			}
+		}
+	}
+	MPN_NORMALIZE(x->d, x->nlimbs);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_rshift);

linux-7.2.3/lib/crypto/mpi/mpi-cmp.c

@@ -0,0 +1,74 @@
+/* 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 <linux/export.h>
+
+#include "mpi-internal.h"
+
+int mpi_cmp_ui(MPI u, unsigned long v)
+{
+	mpi_limb_t limb = v;
+
+	mpi_normalize(u);
+	if (u->nlimbs == 0) {
+		if (v == 0)
+			return 0;
+		else
+			return -1;
+	}
+	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;
+}
+EXPORT_SYMBOL_GPL(mpi_cmp_ui);
+
+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 (u->sign)
+		return -cmp;
+	return cmp;
+}
+EXPORT_SYMBOL_GPL(mpi_cmp);

linux-7.2.3/lib/crypto/mpi/mpi-div.c

@@ -0,0 +1,230 @@
+/* mpi-div.c  -  MPI functions
+ * Copyright (C) 1994, 1996, 1998, 2001, 2002,
+ *               2003 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * 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.
+ */
+
+#include "mpi-internal.h"
+#include "longlong.h"
+
+int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den);
+
+int mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor)
+{
+	int divisor_sign = divisor->sign;
+	MPI temp_divisor = NULL;
+	int err;
+
+	/* We need the original value of the divisor after the remainder has been
+	 * preliminary calculated.	We have to copy it to temporary space if it's
+	 * the same variable as REM.
+	 */
+	if (rem == divisor) {
+		temp_divisor = mpi_copy(divisor);
+		if (!temp_divisor)
+			return -ENOMEM;
+		divisor = temp_divisor;
+	}
+
+	err = mpi_tdiv_r(rem, dividend, divisor);
+	if (err)
+		goto free_temp_divisor;
+
+	if (((divisor_sign?1:0) ^ (dividend->sign?1:0)) && rem->nlimbs)
+		err = mpi_add(rem, rem, divisor);
+
+free_temp_divisor:
+	mpi_free(temp_divisor);
+
+	return err;
+}
+
+/* If den == quot, den needs temporary storage.
+ * If den == rem, den needs temporary storage.
+ * If num == quot, num needs temporary storage.
+ * If den has temporary storage, it can be normalized while being copied,
+ *   i.e no extra storage should be allocated.
+ */
+
+int mpi_tdiv_r(MPI rem, MPI num, MPI den)
+{
+	return mpi_tdiv_qr(NULL, rem, num, den);
+}
+
+int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
+{
+	mpi_ptr_t np, dp;
+	mpi_ptr_t qp, rp;
+	mpi_size_t nsize = num->nlimbs;
+	mpi_size_t dsize = den->nlimbs;
+	mpi_size_t qsize, rsize;
+	mpi_size_t sign_remainder = num->sign;
+	mpi_size_t sign_quotient = num->sign ^ den->sign;
+	unsigned int normalization_steps;
+	mpi_limb_t q_limb;
+	mpi_ptr_t marker[5];
+	int markidx = 0;
+	int err;
+
+	/* Ensure space is enough for quotient and remainder.
+	 * We need space for an extra limb in the remainder, because it's
+	 * up-shifted (normalized) below.
+	 */
+	rsize = nsize + 1;
+	err = mpi_resize(rem, rsize);
+	if (err)
+		return err;
+
+	qsize = rsize - dsize;	  /* qsize cannot be bigger than this.	*/
+	if (qsize <= 0) {
+		if (num != rem) {
+			rem->nlimbs = num->nlimbs;
+			rem->sign = num->sign;
+			MPN_COPY(rem->d, num->d, nsize);
+		}
+		if (quot) {
+			/* This needs to follow the assignment to rem, in case the
+			 * numerator and quotient are the same.
+			 */
+			quot->nlimbs = 0;
+			quot->sign = 0;
+		}
+		return 0;
+	}
+
+	if (quot) {
+		err = mpi_resize(quot, qsize);
+		if (err)
+			return err;
+	}
+
+	/* Read pointers here, when reallocation is finished.  */
+	np = num->d;
+	dp = den->d;
+	rp = rem->d;
+
+	/* Optimize division by a single-limb divisor.  */
+	if (dsize == 1) {
+		mpi_limb_t rlimb;
+		if (quot) {
+			qp = quot->d;
+			rlimb = mpihelp_divmod_1(qp, np, nsize, dp[0]);
+			qsize -= qp[qsize - 1] == 0;
+			quot->nlimbs = qsize;
+			quot->sign = sign_quotient;
+		} else
+			rlimb = mpihelp_mod_1(np, nsize, dp[0]);
+		rp[0] = rlimb;
+		rsize = rlimb != 0?1:0;
+		rem->nlimbs = rsize;
+		rem->sign = sign_remainder;
+		return 0;
+	}
+
+	err = -ENOMEM;
+	if (quot) {
+		qp = quot->d;
+		/* Make sure QP and NP point to different objects.  Otherwise the
+		 * numerator would be gradually overwritten by the quotient limbs.
+		 */
+		if (qp == np) { /* Copy NP object to temporary space.  */
+			np = marker[markidx++] = mpi_alloc_limb_space(nsize);
+			if (!np)
+				goto out_free_marker;
+			MPN_COPY(np, qp, nsize);
+		}
+	} else /* Put quotient at top of remainder. */
+		qp = rp + dsize;
+
+	normalization_steps = count_leading_zeros(dp[dsize - 1]);
+
+	/* Normalize the denominator, i.e. make its most significant bit set by
+	 * shifting it NORMALIZATION_STEPS bits to the left.  Also shift the
+	 * numerator the same number of steps (to keep the quotient the same!).
+	 */
+	if (normalization_steps) {
+		mpi_ptr_t tp;
+		mpi_limb_t nlimb;
+
+		/* Shift up the denominator setting the most significant bit of
+		 * the most significant word.  Use temporary storage not to clobber
+		 * the original contents of the denominator.
+		 */
+		tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
+		if (!tp)
+			goto out_free_marker;
+		mpihelp_lshift(tp, dp, dsize, normalization_steps);
+		dp = tp;
+
+		/* Shift up the numerator, possibly introducing a new most
+		 * significant word.  Move the shifted numerator in the remainder
+		 * meanwhile.
+		 */
+		nlimb = mpihelp_lshift(rp, np, nsize, normalization_steps);
+		if (nlimb) {
+			rp[nsize] = nlimb;
+			rsize = nsize + 1;
+		} else
+			rsize = nsize;
+	} else {
+		/* The denominator is already normalized, as required.	Copy it to
+		 * temporary space if it overlaps with the quotient or remainder.
+		 */
+		if (dp == rp || (quot && (dp == qp))) {
+			mpi_ptr_t tp;
+
+			tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
+			if (!tp)
+				goto out_free_marker;
+			MPN_COPY(tp, dp, dsize);
+			dp = tp;
+		}
+
+		/* Move the numerator to the remainder.  */
+		if (rp != np)
+			MPN_COPY(rp, np, nsize);
+
+		rsize = nsize;
+	}
+
+	q_limb = mpihelp_divrem(qp, 0, rp, rsize, dp, dsize);
+
+	if (quot) {
+		qsize = rsize - dsize;
+		if (q_limb) {
+			qp[qsize] = q_limb;
+			qsize += 1;
+		}
+
+		quot->nlimbs = qsize;
+		quot->sign = sign_quotient;
+	}
+
+	rsize = dsize;
+	MPN_NORMALIZE(rp, rsize);
+
+	if (normalization_steps && rsize) {
+		mpihelp_rshift(rp, rp, rsize, normalization_steps);
+		rsize -= rp[rsize - 1] == 0?1:0;
+	}
+
+	rem->nlimbs = rsize;
+	rem->sign	= sign_remainder;
+
+	err = 0;
+
+out_free_marker:
+	while (markidx) {
+		markidx--;
+		mpi_free_limb_space(marker[markidx]);
+	}
+
+	return err;
+}

linux-7.2.3/lib/crypto/mpi/mpi-inline.h

@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* mpi-inline.h  -  Internal to the Multi Precision Integers
+ *	Copyright (C) 1994, 1996, 1998, 1999 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.
+ */
+
+#ifndef G10_MPI_INLINE_H
+#define G10_MPI_INLINE_H
+
+#ifndef G10_MPI_INLINE_DECL
+#define G10_MPI_INLINE_DECL  static inline
+#endif
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+	      mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+	mpi_limb_t x;
+
+	x = *s1_ptr++;
+	s2_limb += x;
+	*res_ptr++ = s2_limb;
+	if (s2_limb < x) {	/* sum is less than the left operand: handle carry */
+		while (--s1_size) {
+			x = *s1_ptr++ + 1;	/* add carry */
+			*res_ptr++ = x;	/* and store */
+			if (x)	/* not 0 (no overflow): we can stop */
+				goto leave;
+		}
+		return 1;	/* return carry (size of s1 to small) */
+	}
+
+leave:
+	if (res_ptr != s1_ptr) {	/* not the same variable */
+		mpi_size_t i;	/* copy the rest */
+		for (i = 0; i < s1_size - 1; i++)
+			res_ptr[i] = s1_ptr[i];
+	}
+	return 0;		/* no carry */
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+	    mpi_ptr_t s2_ptr, mpi_size_t s2_size)
+{
+	mpi_limb_t cy = 0;
+
+	if (s2_size)
+		cy = mpihelp_add_n(res_ptr, s1_ptr, s2_ptr, s2_size);
+
+	if (s1_size - s2_size)
+		cy = mpihelp_add_1(res_ptr + s2_size, s1_ptr + s2_size,
+				   s1_size - s2_size, cy);
+	return cy;
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+	      mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+	mpi_limb_t x;
+
+	x = *s1_ptr++;
+	s2_limb = x - s2_limb;
+	*res_ptr++ = s2_limb;
+	if (s2_limb > x) {
+		while (--s1_size) {
+			x = *s1_ptr++;
+			*res_ptr++ = x - 1;
+			if (x)
+				goto leave;
+		}
+		return 1;
+	}
+
+leave:
+	if (res_ptr != s1_ptr) {
+		mpi_size_t i;
+		for (i = 0; i < s1_size - 1; i++)
+			res_ptr[i] = s1_ptr[i];
+	}
+	return 0;
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+	    mpi_ptr_t s2_ptr, mpi_size_t s2_size)
+{
+	mpi_limb_t cy = 0;
+
+	if (s2_size)
+		cy = mpihelp_sub_n(res_ptr, s1_ptr, s2_ptr, s2_size);
+
+	if (s1_size - s2_size)
+		cy = mpihelp_sub_1(res_ptr + s2_size, s1_ptr + s2_size,
+				   s1_size - s2_size, cy);
+	return cy;
+}
+
+#endif /*G10_MPI_INLINE_H */

linux-7.2.3/lib/crypto/mpi/mpi-internal.h

@@ -0,0 +1,223 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* mpi-internal.h  -  Internal to the Multi Precision Integers
+ *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
+ *	Copyright (C) 1998, 2000 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.
+ */
+
+#ifndef G10_MPI_INTERNAL_H
+#define G10_MPI_INTERNAL_H
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/mpi.h>
+#include <linux/errno.h>
+
+#define log_debug printk
+#define log_bug printk
+
+#define assert(x) \
+	do { \
+		if (!x) \
+			log_bug("failed assertion\n"); \
+	} while (0);
+
+/* If KARATSUBA_THRESHOLD is not already defined, define it to a
+ * value which is good on most machines.  */
+
+/* tested 4, 16, 32 and 64, where 16 gave the best performance when
+ * checking a 768 and a 1024 bit ElGamal signature.
+ * (wk 22.12.97) */
+#ifndef KARATSUBA_THRESHOLD
+#define KARATSUBA_THRESHOLD 16
+#endif
+
+/* The code can't handle KARATSUBA_THRESHOLD smaller than 2.  */
+#if KARATSUBA_THRESHOLD < 2
+#undef KARATSUBA_THRESHOLD
+#define KARATSUBA_THRESHOLD 2
+#endif
+
+typedef mpi_limb_t *mpi_ptr_t;	/* pointer to a limb */
+typedef int mpi_size_t;		/* (must be a signed type) */
+
+static inline int RESIZE_IF_NEEDED(MPI a, unsigned b)
+{
+	if (a->alloced < b)
+		return mpi_resize(a, b);
+	return 0;
+}
+
+/* Copy N limbs from S to D.  */
+#define MPN_COPY(d, s, n) \
+	do {					\
+		mpi_size_t _i;			\
+		for (_i = 0; _i < (n); _i++)	\
+			(d)[_i] = (s)[_i];	\
+	} while (0)
+
+#define MPN_COPY_DECR(d, s, n) \
+	do {					\
+		mpi_size_t _i;			\
+		for (_i = (n)-1; _i >= 0; _i--) \
+			(d)[_i] = (s)[_i];	\
+	} while (0)
+
+/* Zero N limbs at D */
+#define MPN_ZERO(d, n) \
+	do {					\
+		int  _i;			\
+		for (_i = 0; _i < (n); _i++)	\
+			(d)[_i] = 0;		\
+	} while (0)
+
+#define MPN_NORMALIZE(d, n)  \
+	do {					\
+		while ((n) > 0) {		\
+			if ((d)[(n)-1])		\
+				break;		\
+			(n)--;			\
+		}				\
+	} while (0)
+
+#define MPN_MUL_N_RECURSE(prodp, up, vp, size, tspace) \
+	do {							\
+		if ((size) < KARATSUBA_THRESHOLD)		\
+			mul_n_basecase(prodp, up, vp, size);	\
+		else						\
+			mul_n(prodp, up, vp, size, tspace);	\
+	} while (0);
+
+/* Divide the two-limb number in (NH,,NL) by D, with DI being the largest
+ * limb not larger than (2**(2*BITS_PER_MP_LIMB))/D - (2**BITS_PER_MP_LIMB).
+ * If this would yield overflow, DI should be the largest possible number
+ * (i.e., only ones).  For correct operation, the most significant bit of D
+ * has to be set.  Put the quotient in Q and the remainder in R.
+ */
+#define UDIV_QRNND_PREINV(q, r, nh, nl, d, di)				\
+	do {								\
+		mpi_limb_t _ql __maybe_unused;				\
+		mpi_limb_t _q, _r;					\
+		mpi_limb_t _xh, _xl;					\
+		umul_ppmm(_q, _ql, (nh), (di));				\
+		_q += (nh);	/* DI is 2**BITS_PER_MPI_LIMB too small */ \
+		umul_ppmm(_xh, _xl, _q, (d));				\
+		sub_ddmmss(_xh, _r, (nh), (nl), _xh, _xl);		\
+		if (_xh) {						\
+			sub_ddmmss(_xh, _r, _xh, _r, 0, (d));		\
+			_q++;						\
+			if (_xh) {					\
+				sub_ddmmss(_xh, _r, _xh, _r, 0, (d));	\
+				_q++;					\
+			}						\
+		}							\
+		if (_r >= (d)) {					\
+			_r -= (d);					\
+			_q++;						\
+		}							\
+		(r) = _r;						\
+		(q) = _q;						\
+	} while (0)
+
+
+/*-- mpiutil.c --*/
+mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs);
+void mpi_free_limb_space(mpi_ptr_t a);
+void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs);
+
+static inline mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+			 mpi_size_t s1_size, mpi_limb_t s2_limb);
+mpi_limb_t mpihelp_add_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+			 mpi_ptr_t s2_ptr, mpi_size_t size);
+static inline mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+		       mpi_ptr_t s2_ptr, mpi_size_t s2_size);
+
+static inline mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+			 mpi_size_t s1_size, mpi_limb_t s2_limb);
+mpi_limb_t mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+			 mpi_ptr_t s2_ptr, mpi_size_t size);
+static inline mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+		       mpi_ptr_t s2_ptr, mpi_size_t s2_size);
+
+/*-- mpih-cmp.c --*/
+int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size);
+
+/*-- mpih-mul.c --*/
+
+struct karatsuba_ctx {
+	struct karatsuba_ctx *next;
+	mpi_ptr_t tspace;
+	mpi_size_t tspace_size;
+	mpi_ptr_t tp;
+	mpi_size_t tp_size;
+};
+
+void mpihelp_release_karatsuba_ctx(struct karatsuba_ctx *ctx);
+
+mpi_limb_t mpihelp_addmul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+			    mpi_size_t s1_size, mpi_limb_t s2_limb);
+mpi_limb_t mpihelp_submul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+			    mpi_size_t s1_size, mpi_limb_t s2_limb);
+int mpihelp_mul(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t usize,
+		mpi_ptr_t vp, mpi_size_t vsize, mpi_limb_t *_result);
+void mpih_sqr_n_basecase(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size);
+void mpih_sqr_n(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size,
+		mpi_ptr_t tspace);
+
+int mpihelp_mul_karatsuba_case(mpi_ptr_t prodp,
+			       mpi_ptr_t up, mpi_size_t usize,
+			       mpi_ptr_t vp, mpi_size_t vsize,
+			       struct karatsuba_ctx *ctx);
+
+/*-- generic_mpih-mul1.c --*/
+mpi_limb_t mpihelp_mul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+			 mpi_size_t s1_size, mpi_limb_t s2_limb);
+
+/*-- mpih-div.c --*/
+mpi_limb_t mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
+			 mpi_limb_t divisor_limb);
+mpi_limb_t mpihelp_divrem(mpi_ptr_t qp, mpi_size_t qextra_limbs,
+			  mpi_ptr_t np, mpi_size_t nsize,
+			  mpi_ptr_t dp, mpi_size_t dsize);
+mpi_limb_t mpihelp_divmod_1(mpi_ptr_t quot_ptr,
+			    mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
+			    mpi_limb_t divisor_limb);
+
+/*-- generic_mpih-[lr]shift.c --*/
+mpi_limb_t mpihelp_lshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
+			  unsigned cnt);
+mpi_limb_t mpihelp_rshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
+			  unsigned cnt);
+
+/* Define stuff for longlong.h.  */
+#define W_TYPE_SIZE BITS_PER_MPI_LIMB
+typedef mpi_limb_t UWtype;
+typedef unsigned int UHWtype;
+#if defined(__GNUC__)
+typedef unsigned int UQItype __attribute__ ((mode(QI)));
+typedef int SItype __attribute__ ((mode(SI)));
+typedef unsigned int USItype __attribute__ ((mode(SI)));
+typedef int DItype __attribute__ ((mode(DI)));
+typedef unsigned int UDItype __attribute__ ((mode(DI)));
+#else
+typedef unsigned char UQItype;
+typedef long SItype;
+typedef unsigned long USItype;
+#endif
+
+#ifdef __GNUC__
+#include "mpi-inline.h"
+#endif
+
+#endif /*G10_MPI_INTERNAL_H */

linux-7.2.3/lib/crypto/mpi/mpi-mod.c

@@ -0,0 +1,13 @@
+/* mpi-mod.c -  Modular reduction
+ * Copyright (C) 1998, 1999, 2001, 2002, 2003,
+ *               2007  Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ */
+
+#include "mpi-internal.h"
+
+int mpi_mod(MPI rem, MPI dividend, MPI divisor)
+{
+	return mpi_fdiv_r(rem, dividend, divisor);
+}

linux-7.2.3/lib/crypto/mpi/mpi-mul.c

@@ -0,0 +1,111 @@
+/* mpi-mul.c  -  MPI functions
+ * Copyright (C) 1994, 1996, 1998, 2001, 2002,
+ *               2003 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * 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.
+ */
+
+#include <linux/export.h>
+
+#include "mpi-internal.h"
+
+int mpi_mul(MPI w, MPI u, MPI v)
+{
+	mpi_size_t usize, vsize, wsize;
+	mpi_ptr_t up, vp, wp;
+	mpi_limb_t cy;
+	int usign, vsign, sign_product;
+	int assign_wp = 0;
+	mpi_ptr_t tmp_limb = NULL;
+	int err = 0;
+
+	if (u->nlimbs < v->nlimbs) {
+		/* Swap U and V. */
+		usize = v->nlimbs;
+		usign = v->sign;
+		up    = v->d;
+		vsize = u->nlimbs;
+		vsign = u->sign;
+		vp    = u->d;
+	} else {
+		usize = u->nlimbs;
+		usign = u->sign;
+		up    = u->d;
+		vsize = v->nlimbs;
+		vsign = v->sign;
+		vp    = v->d;
+	}
+	sign_product = usign ^ vsign;
+	wp = w->d;
+
+	/* Ensure W has space enough to store the result.  */
+	wsize = usize + vsize;
+	if (w->alloced < wsize) {
+		if (wp == up || wp == vp) {
+			wp = mpi_alloc_limb_space(wsize);
+			if (!wp)
+				return -ENOMEM;
+			assign_wp = 1;
+		} else {
+			err = mpi_resize(w, wsize);
+			if (err)
+				return err;
+			wp = w->d;
+		}
+	} else { /* Make U and V not overlap with W.	*/
+		if (wp == up) {
+			/* W and U are identical.  Allocate temporary space for U. */
+			up = tmp_limb = mpi_alloc_limb_space(usize);
+			if (!up)
+				return -ENOMEM;
+			/* Is V identical too?  Keep it identical with U.  */
+			if (wp == vp)
+				vp = up;
+			/* Copy to the temporary space.  */
+			MPN_COPY(up, wp, usize);
+		} else if (wp == vp) {
+			/* W and V are identical.  Allocate temporary space for V. */
+			vp = tmp_limb = mpi_alloc_limb_space(vsize);
+			if (!vp)
+				return -ENOMEM;
+			/* Copy to the temporary space.  */
+			MPN_COPY(vp, wp, vsize);
+		}
+	}
+
+	if (!vsize)
+		wsize = 0;
+	else {
+		err = mpihelp_mul(wp, up, usize, vp, vsize, &cy);
+		if (err) {
+			if (assign_wp)
+				mpi_free_limb_space(wp);
+			goto free_tmp_limb;
+		}
+		wsize -= cy ? 0:1;
+	}
+
+	if (assign_wp)
+		mpi_assign_limb_space(w, wp, wsize);
+	w->nlimbs = wsize;
+	w->sign = sign_product;
+
+free_tmp_limb:
+	if (tmp_limb)
+		mpi_free_limb_space(tmp_limb);
+	return err;
+}
+EXPORT_SYMBOL_GPL(mpi_mul);
+
+int mpi_mulm(MPI w, MPI u, MPI v, MPI m)
+{
+	return mpi_mul(w, u, v) ?:
+	       mpi_tdiv_r(w, w, m);
+}
+EXPORT_SYMBOL_GPL(mpi_mulm);

linux-7.2.3/lib/crypto/mpi/mpi-pow.c

@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpi-pow.c  -  MPI functions
+ *	Copyright (C) 1994, 1996, 1998, 2000 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 <linux/export.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+
+#include "mpi-internal.h"
+#include "longlong.h"
+
+/****************
+ * RES = BASE ^ EXP mod MOD
+ */
+int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
+{
+	mpi_ptr_t mp_marker = NULL, bp_marker = NULL, ep_marker = NULL;
+	struct karatsuba_ctx karactx = {};
+	mpi_ptr_t xp_marker = NULL;
+	mpi_ptr_t tspace = NULL;
+	mpi_ptr_t rp, ep, mp, bp;
+	mpi_size_t esize, msize, bsize, rsize;
+	int msign, bsign, rsign;
+	mpi_size_t size;
+	int mod_shift_cnt;
+	int negative_result;
+	int assign_rp = 0;
+	mpi_size_t tsize = 0;	/* to avoid compiler warning */
+	/* fixme: we should check that the warning is void */
+	int rc = -ENOMEM;
+
+	esize = exp->nlimbs;
+	msize = mod->nlimbs;
+	size = 2 * msize;
+	msign = mod->sign;
+
+	rp = res->d;
+	ep = exp->d;
+
+	if (!msize)
+		return -EINVAL;
+
+	if (!esize) {
+		/* Exponent is zero, result is 1 mod MOD, i.e., 1 or 0
+		 * depending on if MOD equals 1.  */
+		res->nlimbs = (msize == 1 && mod->d[0] == 1) ? 0 : 1;
+		if (res->nlimbs) {
+			if (mpi_resize(res, 1) < 0)
+				goto enomem;
+			rp = res->d;
+			rp[0] = 1;
+		}
+		res->sign = 0;
+		goto leave;
+	}
+
+	/* Normalize MOD (i.e. make its most significant bit set) as required by
+	 * mpn_divrem.  This will make the intermediate values in the calculation
+	 * slightly larger, but the correct result is obtained after a final
+	 * reduction using the original MOD value.  */
+	mp = mp_marker = mpi_alloc_limb_space(msize);
+	if (!mp)
+		goto enomem;
+	mod_shift_cnt = count_leading_zeros(mod->d[msize - 1]);
+	if (mod_shift_cnt)
+		mpihelp_lshift(mp, mod->d, msize, mod_shift_cnt);
+	else
+		MPN_COPY(mp, mod->d, msize);
+
+	bsize = base->nlimbs;
+	bsign = base->sign;
+	if (bsize > msize) {	/* The base is larger than the module. Reduce it. */
+		/* Allocate (BSIZE + 1) with space for remainder and quotient.
+		 * (The quotient is (bsize - msize + 1) limbs.)  */
+		bp = bp_marker = mpi_alloc_limb_space(bsize + 1);
+		if (!bp)
+			goto enomem;
+		MPN_COPY(bp, base->d, bsize);
+		/* We don't care about the quotient, store it above the remainder,
+		 * at BP + MSIZE.  */
+		mpihelp_divrem(bp + msize, 0, bp, bsize, mp, msize);
+		bsize = msize;
+		/* Canonicalize the base, since we are going to multiply with it
+		 * quite a few times.  */
+		MPN_NORMALIZE(bp, bsize);
+	} else
+		bp = base->d;
+
+	if (!bsize) {
+		res->nlimbs = 0;
+		res->sign = 0;
+		goto leave;
+	}
+
+	if (res->alloced < size) {
+		/* We have to allocate more space for RES.  If any of the input
+		 * parameters are identical to RES, defer deallocation of the old
+		 * space.  */
+		if (rp == ep || rp == mp || rp == bp) {
+			rp = mpi_alloc_limb_space(size);
+			if (!rp)
+				goto enomem;
+			assign_rp = 1;
+		} else {
+			if (mpi_resize(res, size) < 0)
+				goto enomem;
+			rp = res->d;
+		}
+	} else {		/* Make BASE, EXP and MOD not overlap with RES.  */
+		if (rp == bp) {
+			/* RES and BASE are identical.  Allocate temp. space for BASE.  */
+			BUG_ON(bp_marker);
+			bp = bp_marker = mpi_alloc_limb_space(bsize);
+			if (!bp)
+				goto enomem;
+			MPN_COPY(bp, rp, bsize);
+		}
+		if (rp == ep) {
+			/* RES and EXP are identical.  Allocate temp. space for EXP.  */
+			ep = ep_marker = mpi_alloc_limb_space(esize);
+			if (!ep)
+				goto enomem;
+			MPN_COPY(ep, rp, esize);
+		}
+		if (rp == mp) {
+			/* RES and MOD are identical.  Allocate temporary space for MOD. */
+			BUG_ON(mp_marker);
+			mp = mp_marker = mpi_alloc_limb_space(msize);
+			if (!mp)
+				goto enomem;
+			MPN_COPY(mp, rp, msize);
+		}
+	}
+
+	MPN_COPY(rp, bp, bsize);
+	rsize = bsize;
+	rsign = bsign;
+
+	{
+		mpi_size_t i;
+		mpi_ptr_t xp;
+		int c;
+		mpi_limb_t e;
+		mpi_limb_t carry_limb;
+
+		xp = xp_marker = mpi_alloc_limb_space(2 * (msize + 1));
+		if (!xp)
+			goto enomem;
+
+		negative_result = (ep[0] & 1) && base->sign;
+
+		i = esize - 1;
+		e = ep[i];
+		c = count_leading_zeros(e);
+		e = (e << c) << 1;	/* shift the exp bits to the left, lose msb */
+		c = BITS_PER_MPI_LIMB - 1 - c;
+
+		/* Main loop.
+		 *
+		 * Make the result be pointed to alternately by XP and RP.  This
+		 * helps us avoid block copying, which would otherwise be necessary
+		 * with the overlap restrictions of mpihelp_divmod. With 50% probability
+		 * the result after this loop will be in the area originally pointed
+		 * by RP (==RES->d), and with 50% probability in the area originally
+		 * pointed to by XP.
+		 */
+
+		for (;;) {
+			while (c) {
+				mpi_size_t xsize;
+
+				/*if (mpihelp_mul_n(xp, rp, rp, rsize) < 0) goto enomem */
+				if (rsize < KARATSUBA_THRESHOLD)
+					mpih_sqr_n_basecase(xp, rp, rsize);
+				else {
+					if (!tspace) {
+						tsize = 2 * rsize;
+						tspace =
+						    mpi_alloc_limb_space(tsize);
+						if (!tspace)
+							goto enomem;
+					} else if (tsize < (2 * rsize)) {
+						mpi_free_limb_space(tspace);
+						tsize = 2 * rsize;
+						tspace =
+						    mpi_alloc_limb_space(tsize);
+						if (!tspace)
+							goto enomem;
+					}
+					mpih_sqr_n(xp, rp, rsize, tspace);
+				}
+
+				xsize = 2 * rsize;
+				if (xsize > msize) {
+					mpihelp_divrem(xp + msize, 0, xp, xsize,
+						       mp, msize);
+					xsize = msize;
+				}
+
+				swap(rp, xp);
+				rsize = xsize;
+
+				if ((mpi_limb_signed_t) e < 0) {
+					/*mpihelp_mul( xp, rp, rsize, bp, bsize ); */
+					if (bsize < KARATSUBA_THRESHOLD) {
+						mpi_limb_t tmp;
+						if (mpihelp_mul
+						    (xp, rp, rsize, bp, bsize,
+						     &tmp) < 0)
+							goto enomem;
+					} else {
+						if (mpihelp_mul_karatsuba_case
+						    (xp, rp, rsize, bp, bsize,
+						     &karactx) < 0)
+							goto enomem;
+					}
+
+					xsize = rsize + bsize;
+					if (xsize > msize) {
+						mpihelp_divrem(xp + msize, 0,
+							       xp, xsize, mp,
+							       msize);
+						xsize = msize;
+					}
+
+					swap(rp, xp);
+					rsize = xsize;
+				}
+				e <<= 1;
+				c--;
+				cond_resched();
+			}
+
+			i--;
+			if (i < 0)
+				break;
+			e = ep[i];
+			c = BITS_PER_MPI_LIMB;
+		}
+
+		/* We shifted MOD, the modulo reduction argument, left MOD_SHIFT_CNT
+		 * steps.  Adjust the result by reducing it with the original MOD.
+		 *
+		 * Also make sure the result is put in RES->d (where it already
+		 * might be, see above).
+		 */
+		if (mod_shift_cnt) {
+			carry_limb =
+			    mpihelp_lshift(res->d, rp, rsize, mod_shift_cnt);
+			rp = res->d;
+			if (carry_limb) {
+				rp[rsize] = carry_limb;
+				rsize++;
+			}
+		} else {
+			MPN_COPY(res->d, rp, rsize);
+			rp = res->d;
+		}
+
+		if (rsize >= msize) {
+			mpihelp_divrem(rp + msize, 0, rp, rsize, mp, msize);
+			rsize = msize;
+		}
+
+		/* Remove any leading zero words from the result.  */
+		if (mod_shift_cnt)
+			mpihelp_rshift(rp, rp, rsize, mod_shift_cnt);
+		MPN_NORMALIZE(rp, rsize);
+	}
+
+	if (negative_result && rsize) {
+		if (mod_shift_cnt)
+			mpihelp_rshift(mp, mp, msize, mod_shift_cnt);
+		mpihelp_sub(rp, mp, msize, rp, rsize);
+		rsize = msize;
+		rsign = msign;
+		MPN_NORMALIZE(rp, rsize);
+	}
+	res->nlimbs = rsize;
+	res->sign = rsign;
+
+leave:
+	rc = 0;
+enomem:
+	mpihelp_release_karatsuba_ctx(&karactx);
+	if (assign_rp)
+		mpi_assign_limb_space(res, rp, size);
+	if (mp_marker)
+		mpi_free_limb_space(mp_marker);
+	if (bp_marker)
+		mpi_free_limb_space(bp_marker);
+	if (ep_marker)
+		mpi_free_limb_space(ep_marker);
+	if (xp_marker)
+		mpi_free_limb_space(xp_marker);
+	if (tspace)
+		mpi_free_limb_space(tspace);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(mpi_powm);

linux-7.2.3/lib/crypto/mpi/mpi-sub-ui.c

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpi-sub-ui.c - Subtract an unsigned integer from an MPI.
+ *
+ * Copyright 1991, 1993, 1994, 1996, 1999-2002, 2004, 2012, 2013, 2015
+ * Free Software Foundation, Inc.
+ *
+ * This file was based on the GNU MP Library source file:
+ * https://gmplib.org/repo/gmp-6.2/file/510b83519d1c/mpz/aors_ui.h
+ *
+ * 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 <linux/export.h>
+
+#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);

linux-7.2.3/lib/crypto/mpi/mpicoder.c

@@ -0,0 +1,417 @@
+/* mpicoder.c  -  Coder for the external representation of MPIs
+ * 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 <linux/bitops.h>
+#include <linux/byteorder/generic.h>
+#include <linux/count_zeros.h>
+#include <linux/export.h>
+#include <linux/scatterlist.h>
+#include <linux/string.h>
+#include "mpi-internal.h"
+
+#define MAX_EXTERN_MPI_BITS 16384
+
+/**
+ * mpi_read_raw_data - Read a raw byte stream as a positive integer
+ * @xbuffer: The data to read
+ * @nbytes: The amount of data to read
+ */
+MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes)
+{
+	const uint8_t *buffer = xbuffer;
+	int i, j;
+	unsigned nbits, nlimbs;
+	mpi_limb_t a;
+	MPI val = NULL;
+
+	while (nbytes > 0 && buffer[0] == 0) {
+		buffer++;
+		nbytes--;
+	}
+
+	nbits = nbytes * 8;
+	if (nbits > MAX_EXTERN_MPI_BITS) {
+		pr_info("MPI: mpi too large (%u bits)\n", nbits);
+		return NULL;
+	}
+	if (nbytes > 0)
+		nbits -= count_leading_zeros(buffer[0]) - (BITS_PER_LONG - 8);
+
+	nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
+	val = mpi_alloc(nlimbs);
+	if (!val)
+		return NULL;
+	val->nbits = nbits;
+	val->sign = 0;
+	val->nlimbs = nlimbs;
+
+	if (nbytes > 0) {
+		i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+		i %= BYTES_PER_MPI_LIMB;
+		for (j = nlimbs; j > 0; j--) {
+			a = 0;
+			for (; i < BYTES_PER_MPI_LIMB; i++) {
+				a <<= 8;
+				a |= *buffer++;
+			}
+			i = 0;
+			val->d[j - 1] = a;
+		}
+	}
+	return val;
+}
+EXPORT_SYMBOL_GPL(mpi_read_raw_data);
+
+MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
+{
+	const uint8_t *buffer = xbuffer;
+	unsigned int nbits, nbytes;
+	MPI val;
+
+	if (*ret_nread < 2)
+		return ERR_PTR(-EINVAL);
+	nbits = buffer[0] << 8 | buffer[1];
+
+	if (nbits > MAX_EXTERN_MPI_BITS) {
+		pr_info("MPI: mpi too large (%u bits)\n", nbits);
+		return ERR_PTR(-EINVAL);
+	}
+
+	nbytes = DIV_ROUND_UP(nbits, 8);
+	if (nbytes + 2 > *ret_nread) {
+		pr_info("MPI: mpi larger than buffer nbytes=%u ret_nread=%u\n",
+				nbytes, *ret_nread);
+		return ERR_PTR(-EINVAL);
+	}
+
+	val = mpi_read_raw_data(buffer + 2, nbytes);
+	if (!val)
+		return ERR_PTR(-ENOMEM);
+
+	*ret_nread = nbytes + 2;
+	return val;
+}
+EXPORT_SYMBOL_GPL(mpi_read_from_buffer);
+
+static int count_lzeros(MPI a)
+{
+	mpi_limb_t alimb;
+	int i, lzeros = 0;
+
+	for (i = a->nlimbs - 1; i >= 0; i--) {
+		alimb = a->d[i];
+		if (alimb == 0) {
+			lzeros += sizeof(mpi_limb_t);
+		} else {
+			lzeros += count_leading_zeros(alimb) / 8;
+			break;
+		}
+	}
+	return lzeros;
+}
+
+/**
+ * mpi_read_buffer() - read MPI to a buffer provided by user (msb first)
+ *
+ * @a:		a multi precision integer
+ * @buf:	buffer to which the output will be written to. Needs to be at
+ *		least mpi_get_size(a) long.
+ * @buf_len:	size of the buf.
+ * @nbytes:	receives the actual length of the data written on success and
+ *		the data to-be-written on -EOVERFLOW in case buf_len was too
+ *		small.
+ * @sign:	if not NULL, it will be set to the sign of a.
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
+		    int *sign)
+{
+	uint8_t *p;
+#if BYTES_PER_MPI_LIMB == 4
+	__be32 alimb;
+#elif BYTES_PER_MPI_LIMB == 8
+	__be64 alimb;
+#else
+#error please implement for this limb size.
+#endif
+	unsigned int n = mpi_get_size(a);
+	int i, lzeros;
+
+	if (!buf || !nbytes)
+		return -EINVAL;
+
+	if (sign)
+		*sign = a->sign;
+
+	lzeros = count_lzeros(a);
+
+	if (buf_len < n - lzeros) {
+		*nbytes = n - lzeros;
+		return -EOVERFLOW;
+	}
+
+	p = buf;
+	*nbytes = n - lzeros;
+
+	for (i = a->nlimbs - 1 - lzeros / BYTES_PER_MPI_LIMB,
+			lzeros %= BYTES_PER_MPI_LIMB;
+		i >= 0; i--) {
+#if BYTES_PER_MPI_LIMB == 4
+		alimb = cpu_to_be32(a->d[i]);
+#elif BYTES_PER_MPI_LIMB == 8
+		alimb = cpu_to_be64(a->d[i]);
+#else
+#error please implement for this limb size.
+#endif
+		memcpy(p, (u8 *)&alimb + lzeros, BYTES_PER_MPI_LIMB - lzeros);
+		p += BYTES_PER_MPI_LIMB - lzeros;
+		lzeros = 0;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_read_buffer);
+
+/*
+ * mpi_get_buffer() - Returns an allocated buffer with the MPI (msb first).
+ * Caller must free the return string.
+ * This function does return a 0 byte buffer with nbytes set to zero if the
+ * value of A is zero.
+ *
+ * @a:		a multi precision integer.
+ * @nbytes:	receives the length of this buffer.
+ * @sign:	if not NULL, it will be set to the sign of the a.
+ *
+ * Return:	Pointer to MPI buffer or NULL on error
+ */
+void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign)
+{
+	uint8_t *buf;
+	unsigned int n;
+	int ret;
+
+	if (!nbytes)
+		return NULL;
+
+	n = mpi_get_size(a);
+
+	if (!n)
+		n++;
+
+	buf = kmalloc(n, GFP_KERNEL);
+
+	if (!buf)
+		return NULL;
+
+	ret = mpi_read_buffer(a, buf, n, nbytes, sign);
+
+	if (ret) {
+		kfree(buf);
+		return NULL;
+	}
+	return buf;
+}
+EXPORT_SYMBOL_GPL(mpi_get_buffer);
+
+/**
+ * mpi_write_to_sgl() - Funnction exports MPI to an sgl (msb first)
+ *
+ * This function works in the same way as the mpi_read_buffer, but it
+ * takes an sgl instead of u8 * buf.
+ *
+ * @a:		a multi precision integer
+ * @sgl:	scatterlist to write to. Needs to be at least
+ *		mpi_get_size(a) long.
+ * @nbytes:	the number of bytes to write.  Leading bytes will be
+ *		filled with zero.
+ * @sign:	if not NULL, it will be set to the sign of a.
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned nbytes,
+		     int *sign)
+{
+	u8 *p, *p2;
+#if BYTES_PER_MPI_LIMB == 4
+	__be32 alimb;
+#elif BYTES_PER_MPI_LIMB == 8
+	__be64 alimb;
+#else
+#error please implement for this limb size.
+#endif
+	unsigned int n = mpi_get_size(a);
+	struct sg_mapping_iter miter;
+	int i, x, buf_len;
+	int nents;
+
+	if (sign)
+		*sign = a->sign;
+
+	if (nbytes < n)
+		return -EOVERFLOW;
+
+	nents = sg_nents_for_len(sgl, nbytes);
+	if (nents < 0)
+		return -EINVAL;
+
+	sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC | SG_MITER_TO_SG);
+	sg_miter_next(&miter);
+	buf_len = miter.length;
+	p2 = miter.addr;
+
+	while (nbytes > n) {
+		i = min_t(unsigned, nbytes - n, buf_len);
+		memset(p2, 0, i);
+		p2 += i;
+		nbytes -= i;
+
+		buf_len -= i;
+		if (!buf_len) {
+			sg_miter_next(&miter);
+			buf_len = miter.length;
+			p2 = miter.addr;
+		}
+	}
+
+	for (i = a->nlimbs - 1; i >= 0; i--) {
+#if BYTES_PER_MPI_LIMB == 4
+		alimb = a->d[i] ? cpu_to_be32(a->d[i]) : 0;
+#elif BYTES_PER_MPI_LIMB == 8
+		alimb = a->d[i] ? cpu_to_be64(a->d[i]) : 0;
+#else
+#error please implement for this limb size.
+#endif
+		p = (u8 *)&alimb;
+
+		for (x = 0; x < sizeof(alimb); x++) {
+			*p2++ = *p++;
+			if (!--buf_len) {
+				sg_miter_next(&miter);
+				buf_len = miter.length;
+				p2 = miter.addr;
+			}
+		}
+	}
+
+	sg_miter_stop(&miter);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_write_to_sgl);
+
+/*
+ * mpi_read_raw_from_sgl() - Function allocates an MPI and populates it with
+ *			     data from the sgl
+ *
+ * This function works in the same way as the mpi_read_raw_data, but it
+ * takes an sgl instead of void * buffer. i.e. it allocates
+ * a new MPI and reads the content of the sgl to the MPI.
+ *
+ * @sgl:	scatterlist to read from
+ * @nbytes:	number of bytes to read
+ *
+ * Return:	Pointer to a new MPI or NULL on error
+ */
+MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
+{
+	struct sg_mapping_iter miter;
+	unsigned int nbits, nlimbs;
+	int x, j, z, lzeros, ents;
+	unsigned int len;
+	const u8 *buff;
+	mpi_limb_t a;
+	MPI val = NULL;
+
+	ents = sg_nents_for_len(sgl, nbytes);
+	if (ents < 0)
+		return NULL;
+
+	sg_miter_start(&miter, sgl, ents, SG_MITER_ATOMIC | SG_MITER_FROM_SG);
+
+	lzeros = 0;
+	len = 0;
+	while (nbytes > 0) {
+		while (len && !*buff && lzeros < nbytes) {
+			lzeros++;
+			len--;
+			buff++;
+		}
+
+		if (len && *buff)
+			break;
+
+		sg_miter_next(&miter);
+		buff = miter.addr;
+		len = miter.length;
+
+		nbytes -= lzeros;
+		lzeros = 0;
+	}
+
+	miter.consumed = lzeros;
+
+	nbytes -= lzeros;
+	nbits = nbytes * 8;
+	if (nbits > MAX_EXTERN_MPI_BITS) {
+		sg_miter_stop(&miter);
+		pr_info("MPI: mpi too large (%u bits)\n", nbits);
+		return NULL;
+	}
+
+	if (nbytes > 0)
+		nbits -= count_leading_zeros(*buff) - (BITS_PER_LONG - 8);
+
+	sg_miter_stop(&miter);
+
+	nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
+	val = mpi_alloc(nlimbs);
+	if (!val)
+		return NULL;
+
+	val->nbits = nbits;
+	val->sign = 0;
+	val->nlimbs = nlimbs;
+
+	if (nbytes == 0)
+		return val;
+
+	j = nlimbs - 1;
+	a = 0;
+	z = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+	z %= BYTES_PER_MPI_LIMB;
+
+	while (sg_miter_next(&miter)) {
+		buff = miter.addr;
+		len = min(miter.length, nbytes);
+		nbytes -= len;
+
+		for (x = 0; x < len; x++) {
+			a <<= 8;
+			a |= *buff++;
+			if (((z + x + 1) % BYTES_PER_MPI_LIMB) == 0) {
+				val->d[j--] = a;
+				a = 0;
+			}
+		}
+		z += x;
+	}
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(mpi_read_raw_from_sgl);

linux-7.2.3/lib/crypto/mpi/mpih-cmp.c

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-sub.c  -  MPI helper functions
+ *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
+ *	Copyright (C) 1998, 1999, 2000, 2001 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"
+
+/****************
+ * Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
+ * There are no restrictions on the relative sizes of
+ * the two arguments.
+ * Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.
+ */
+int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size)
+{
+	mpi_size_t i;
+	mpi_limb_t op1_word, op2_word;
+
+	for (i = size - 1; i >= 0; i--) {
+		op1_word = op1_ptr[i];
+		op2_word = op2_ptr[i];
+		if (op1_word != op2_word)
+			goto diff;
+	}
+	return 0;
+
+diff:
+	/* This can *not* be simplified to
+	 *   op2_word - op2_word
+	 * since that expression might give signed overflow.  */
+	return (op1_word > op2_word) ? 1 : -1;
+}

linux-7.2.3/lib/crypto/mpi/mpih-div.c

@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-div.c  -  MPI helper functions
+ *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
+ *	Copyright (C) 1998, 1999 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"
+#include "longlong.h"
+
+#ifndef UMUL_TIME
+#define UMUL_TIME 1
+#endif
+#ifndef UDIV_TIME
+#define UDIV_TIME UMUL_TIME
+#endif
+
+
+mpi_limb_t
+mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
+			mpi_limb_t divisor_limb)
+{
+	mpi_size_t i;
+	mpi_limb_t n1, n0, r;
+	mpi_limb_t dummy __maybe_unused;
+
+	/* Botch: Should this be handled at all?  Rely on callers?	*/
+	if (!dividend_size)
+		return 0;
+
+	/* If multiplication is much faster than division, and the
+	 * dividend is large, pre-invert the divisor, and use
+	 * only multiplications in the inner loop.
+	 *
+	 * This test should be read:
+	 *	 Does it ever help to use udiv_qrnnd_preinv?
+	 *	   && Does what we save compensate for the inversion overhead?
+	 */
+	if (UDIV_TIME > (2 * UMUL_TIME + 6)
+			&& (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME) {
+		int normalization_steps;
+
+		normalization_steps = count_leading_zeros(divisor_limb);
+		if (normalization_steps) {
+			mpi_limb_t divisor_limb_inverted;
+
+			divisor_limb <<= normalization_steps;
+
+			/* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB.  The
+			 * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the
+			 * most significant bit (with weight 2**N) implicit.
+			 *
+			 * Special case for DIVISOR_LIMB == 100...000.
+			 */
+			if (!(divisor_limb << 1))
+				divisor_limb_inverted = ~(mpi_limb_t)0;
+			else
+				udiv_qrnnd(divisor_limb_inverted, dummy,
+						-divisor_limb, 0, divisor_limb);
+
+			n1 = dividend_ptr[dividend_size - 1];
+			r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps);
+
+			/* Possible optimization:
+			 * if (r == 0
+			 * && divisor_limb > ((n1 << normalization_steps)
+			 *		       | (dividend_ptr[dividend_size - 2] >> ...)))
+			 * ...one division less...
+			 */
+			for (i = dividend_size - 2; i >= 0; i--) {
+				n0 = dividend_ptr[i];
+				UDIV_QRNND_PREINV(dummy, r, r,
+						((n1 << normalization_steps)
+						 | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))),
+						divisor_limb, divisor_limb_inverted);
+				n1 = n0;
+			}
+			UDIV_QRNND_PREINV(dummy, r, r,
+					n1 << normalization_steps,
+					divisor_limb, divisor_limb_inverted);
+			return r >> normalization_steps;
+		} else {
+			mpi_limb_t divisor_limb_inverted;
+
+			/* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB.  The
+			 * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the
+			 * most significant bit (with weight 2**N) implicit.
+			 *
+			 * Special case for DIVISOR_LIMB == 100...000.
+			 */
+			if (!(divisor_limb << 1))
+				divisor_limb_inverted = ~(mpi_limb_t)0;
+			else
+				udiv_qrnnd(divisor_limb_inverted, dummy,
+						-divisor_limb, 0, divisor_limb);
+
+			i = dividend_size - 1;
+			r = dividend_ptr[i];
+
+			if (r >= divisor_limb)
+				r = 0;
+			else
+				i--;
+
+			for ( ; i >= 0; i--) {
+				n0 = dividend_ptr[i];
+				UDIV_QRNND_PREINV(dummy, r, r,
+						n0, divisor_limb, divisor_limb_inverted);
+			}
+			return r;
+		}
+	} else {
+		if (UDIV_NEEDS_NORMALIZATION) {
+			int normalization_steps;
+
+			normalization_steps = count_leading_zeros(divisor_limb);
+			if (normalization_steps) {
+				divisor_limb <<= normalization_steps;
+
+				n1 = dividend_ptr[dividend_size - 1];
+				r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps);
+
+				/* Possible optimization:
+				 * if (r == 0
+				 * && divisor_limb > ((n1 << normalization_steps)
+				 *		   | (dividend_ptr[dividend_size - 2] >> ...)))
+				 * ...one division less...
+				 */
+				for (i = dividend_size - 2; i >= 0; i--) {
+					n0 = dividend_ptr[i];
+					udiv_qrnnd(dummy, r, r,
+						((n1 << normalization_steps)
+						 | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))),
+						divisor_limb);
+					n1 = n0;
+				}
+				udiv_qrnnd(dummy, r, r,
+						n1 << normalization_steps,
+						divisor_limb);
+				return r >> normalization_steps;
+			}
+		}
+		/* No normalization needed, either because udiv_qrnnd doesn't require
+		 * it, or because DIVISOR_LIMB is already normalized.
+		 */
+		i = dividend_size - 1;
+		r = dividend_ptr[i];
+
+		if (r >= divisor_limb)
+			r = 0;
+		else
+			i--;
+
+		for (; i >= 0; i--) {
+			n0 = dividend_ptr[i];
+			udiv_qrnnd(dummy, r, r, n0, divisor_limb);
+		}
+		return r;
+	}
+}
+
+/* Divide num (NP/NSIZE) by den (DP/DSIZE) and write
+ * the NSIZE-DSIZE least significant quotient limbs at QP
+ * and the DSIZE long remainder at NP.	If QEXTRA_LIMBS is
+ * non-zero, generate that many fraction bits and append them after the
+ * other quotient limbs.
+ * Return the most significant limb of the quotient, this is always 0 or 1.
+ *
+ * Preconditions:
+ * 0. NSIZE >= DSIZE.
+ * 1. The most significant bit of the divisor must be set.
+ * 2. QP must either not overlap with the input operands at all, or
+ *    QP + DSIZE >= NP must hold true.	(This means that it's
+ *    possible to put the quotient in the high part of NUM, right after the
+ *    remainder in NUM.
+ * 3. NSIZE >= DSIZE, even if QEXTRA_LIMBS is non-zero.
+ */
+
+mpi_limb_t
+mpihelp_divrem(mpi_ptr_t qp, mpi_size_t qextra_limbs,
+	       mpi_ptr_t np, mpi_size_t nsize, mpi_ptr_t dp, mpi_size_t dsize)
+{
+	mpi_limb_t most_significant_q_limb = 0;
+
+	switch (dsize) {
+	case 0:
+		/* We are asked to divide by zero, so go ahead and do it!  (To make
+		   the compiler not remove this statement, return the value.)  */
+		/*
+		 * existing clients of this function have been modified
+		 * not to call it with dsize == 0, so this should not happen
+		 */
+		return 1 / dsize;
+
+	case 1:
+		{
+			mpi_size_t i;
+			mpi_limb_t n1;
+			mpi_limb_t d;
+
+			d = dp[0];
+			n1 = np[nsize - 1];
+
+			if (n1 >= d) {
+				n1 -= d;
+				most_significant_q_limb = 1;
+			}
+
+			qp += qextra_limbs;
+			for (i = nsize - 2; i >= 0; i--)
+				udiv_qrnnd(qp[i], n1, n1, np[i], d);
+			qp -= qextra_limbs;
+
+			for (i = qextra_limbs - 1; i >= 0; i--)
+				udiv_qrnnd(qp[i], n1, n1, 0, d);
+
+			np[0] = n1;
+		}
+		break;
+
+	case 2:
+		{
+			mpi_size_t i;
+			mpi_limb_t n1, n0, n2;
+			mpi_limb_t d1, d0;
+
+			np += nsize - 2;
+			d1 = dp[1];
+			d0 = dp[0];
+			n1 = np[1];
+			n0 = np[0];
+
+			if (n1 >= d1 && (n1 > d1 || n0 >= d0)) {
+				sub_ddmmss(n1, n0, n1, n0, d1, d0);
+				most_significant_q_limb = 1;
+			}
+
+			for (i = qextra_limbs + nsize - 2 - 1; i >= 0; i--) {
+				mpi_limb_t q;
+				mpi_limb_t r;
+
+				if (i >= qextra_limbs)
+					np--;
+				else
+					np[0] = 0;
+
+				if (n1 == d1) {
+					/* Q should be either 111..111 or 111..110.  Need special
+					 * treatment of this rare case as normal division would
+					 * give overflow.  */
+					q = ~(mpi_limb_t) 0;
+
+					r = n0 + d1;
+					if (r < d1) {	/* Carry in the addition? */
+						add_ssaaaa(n1, n0, r - d0,
+							   np[0], 0, d0);
+						qp[i] = q;
+						continue;
+					}
+					n1 = d0 - (d0 != 0 ? 1 : 0);
+					n0 = -d0;
+				} else {
+					udiv_qrnnd(q, r, n1, n0, d1);
+					umul_ppmm(n1, n0, d0, q);
+				}
+
+				n2 = np[0];
+q_test:
+				if (n1 > r || (n1 == r && n0 > n2)) {
+					/* The estimated Q was too large.  */
+					q--;
+					sub_ddmmss(n1, n0, n1, n0, 0, d0);
+					r += d1;
+					if (r >= d1)	/* If not carry, test Q again.  */
+						goto q_test;
+				}
+
+				qp[i] = q;
+				sub_ddmmss(n1, n0, r, n2, n1, n0);
+			}
+			np[1] = n1;
+			np[0] = n0;
+		}
+		break;
+
+	default:
+		{
+			mpi_size_t i;
+			mpi_limb_t dX, d1, n0;
+
+			np += nsize - dsize;
+			dX = dp[dsize - 1];
+			d1 = dp[dsize - 2];
+			n0 = np[dsize - 1];
+
+			if (n0 >= dX) {
+				if (n0 > dX
+				    || mpihelp_cmp(np, dp, dsize - 1) >= 0) {
+					mpihelp_sub_n(np, np, dp, dsize);
+					n0 = np[dsize - 1];
+					most_significant_q_limb = 1;
+				}
+			}
+
+			for (i = qextra_limbs + nsize - dsize - 1; i >= 0; i--) {
+				mpi_limb_t q;
+				mpi_limb_t n1, n2;
+				mpi_limb_t cy_limb;
+
+				if (i >= qextra_limbs) {
+					np--;
+					n2 = np[dsize];
+				} else {
+					n2 = np[dsize - 1];
+					MPN_COPY_DECR(np + 1, np, dsize - 1);
+					np[0] = 0;
+				}
+
+				if (n0 == dX) {
+					/* This might over-estimate q, but it's probably not worth
+					 * the extra code here to find out.  */
+					q = ~(mpi_limb_t) 0;
+				} else {
+					mpi_limb_t r;
+
+					udiv_qrnnd(q, r, n0, np[dsize - 1], dX);
+					umul_ppmm(n1, n0, d1, q);
+
+					while (n1 > r
+					       || (n1 == r
+						   && n0 > np[dsize - 2])) {
+						q--;
+						r += dX;
+						if (r < dX)	/* I.e. "carry in previous addition?" */
+							break;
+						n1 -= n0 < d1;
+						n0 -= d1;
+					}
+				}
+
+				/* Possible optimization: We already have (q * n0) and (1 * n1)
+				 * after the calculation of q.  Taking advantage of that, we
+				 * could make this loop make two iterations less.  */
+				cy_limb = mpihelp_submul_1(np, dp, dsize, q);
+
+				if (n2 != cy_limb) {
+					mpihelp_add_n(np, np, dp, dsize);
+					q--;
+				}
+
+				qp[i] = q;
+				n0 = np[dsize - 1];
+			}
+		}
+	}
+
+	return most_significant_q_limb;
+}
+
+/****************
+ * Divide (DIVIDEND_PTR,,DIVIDEND_SIZE) by DIVISOR_LIMB.
+ * Write DIVIDEND_SIZE limbs of quotient at QUOT_PTR.
+ * Return the single-limb remainder.
+ * There are no constraints on the value of the divisor.
+ *
+ * QUOT_PTR and DIVIDEND_PTR might point to the same limb.
+ */
+
+mpi_limb_t
+mpihelp_divmod_1(mpi_ptr_t quot_ptr,
+		mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
+		mpi_limb_t divisor_limb)
+{
+	mpi_size_t i;
+	mpi_limb_t n1, n0, r;
+	mpi_limb_t dummy __maybe_unused;
+
+	if (!dividend_size)
+		return 0;
+
+	/* If multiplication is much faster than division, and the
+	 * dividend is large, pre-invert the divisor, and use
+	 * only multiplications in the inner loop.
+	 *
+	 * This test should be read:
+	 * Does it ever help to use udiv_qrnnd_preinv?
+	 * && Does what we save compensate for the inversion overhead?
+	 */
+	if (UDIV_TIME > (2 * UMUL_TIME + 6)
+			&& (UDIV_TIME - (2 * UMUL_TIME + 6)) * dividend_size > UDIV_TIME) {
+		int normalization_steps;
+
+		normalization_steps = count_leading_zeros(divisor_limb);
+		if (normalization_steps) {
+			mpi_limb_t divisor_limb_inverted;
+
+			divisor_limb <<= normalization_steps;
+
+			/* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB.  The
+			 * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the
+			 * most significant bit (with weight 2**N) implicit.
+			 */
+			/* Special case for DIVISOR_LIMB == 100...000.  */
+			if (!(divisor_limb << 1))
+				divisor_limb_inverted = ~(mpi_limb_t)0;
+			else
+				udiv_qrnnd(divisor_limb_inverted, dummy,
+						-divisor_limb, 0, divisor_limb);
+
+			n1 = dividend_ptr[dividend_size - 1];
+			r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps);
+
+			/* Possible optimization:
+			 * if (r == 0
+			 * && divisor_limb > ((n1 << normalization_steps)
+			 *		       | (dividend_ptr[dividend_size - 2] >> ...)))
+			 * ...one division less...
+			 */
+			for (i = dividend_size - 2; i >= 0; i--) {
+				n0 = dividend_ptr[i];
+				UDIV_QRNND_PREINV(quot_ptr[i + 1], r, r,
+						((n1 << normalization_steps)
+						 | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))),
+						divisor_limb, divisor_limb_inverted);
+				n1 = n0;
+			}
+			UDIV_QRNND_PREINV(quot_ptr[0], r, r,
+					n1 << normalization_steps,
+					divisor_limb, divisor_limb_inverted);
+			return r >> normalization_steps;
+		} else {
+			mpi_limb_t divisor_limb_inverted;
+
+			/* Compute (2**2N - 2**N * DIVISOR_LIMB) / DIVISOR_LIMB.  The
+			 * result is a (N+1)-bit approximation to 1/DIVISOR_LIMB, with the
+			 * most significant bit (with weight 2**N) implicit.
+			 */
+			/* Special case for DIVISOR_LIMB == 100...000.  */
+			if (!(divisor_limb << 1))
+				divisor_limb_inverted = ~(mpi_limb_t) 0;
+			else
+				udiv_qrnnd(divisor_limb_inverted, dummy,
+						-divisor_limb, 0, divisor_limb);
+
+			i = dividend_size - 1;
+			r = dividend_ptr[i];
+
+			if (r >= divisor_limb)
+				r = 0;
+			else
+				quot_ptr[i--] = 0;
+
+			for ( ; i >= 0; i--) {
+				n0 = dividend_ptr[i];
+				UDIV_QRNND_PREINV(quot_ptr[i], r, r,
+						n0, divisor_limb, divisor_limb_inverted);
+			}
+			return r;
+		}
+	} else {
+		if (UDIV_NEEDS_NORMALIZATION) {
+			int normalization_steps;
+
+			normalization_steps = count_leading_zeros(divisor_limb);
+			if (normalization_steps) {
+				divisor_limb <<= normalization_steps;
+
+				n1 = dividend_ptr[dividend_size - 1];
+				r = n1 >> (BITS_PER_MPI_LIMB - normalization_steps);
+
+				/* Possible optimization:
+				 * if (r == 0
+				 * && divisor_limb > ((n1 << normalization_steps)
+				 *		   | (dividend_ptr[dividend_size - 2] >> ...)))
+				 * ...one division less...
+				 */
+				for (i = dividend_size - 2; i >= 0; i--) {
+					n0 = dividend_ptr[i];
+					udiv_qrnnd(quot_ptr[i + 1], r, r,
+						((n1 << normalization_steps)
+						 | (n0 >> (BITS_PER_MPI_LIMB - normalization_steps))),
+						divisor_limb);
+					n1 = n0;
+				}
+				udiv_qrnnd(quot_ptr[0], r, r,
+						n1 << normalization_steps,
+						divisor_limb);
+				return r >> normalization_steps;
+			}
+		}
+		/* No normalization needed, either because udiv_qrnnd doesn't require
+		 * it, or because DIVISOR_LIMB is already normalized.
+		 */
+		i = dividend_size - 1;
+		r = dividend_ptr[i];
+
+		if (r >= divisor_limb)
+			r = 0;
+		else
+			quot_ptr[i--] = 0;
+
+		for (; i >= 0; i--) {
+			n0 = dividend_ptr[i];
+			udiv_qrnnd(quot_ptr[i], r, r, n0, divisor_limb);
+		}
+		return r;
+	}
+}

linux-7.2.3/lib/crypto/mpi/mpih-mul.c

@@ -0,0 +1,484 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* mpihelp-mul.c  -  MPI helper functions
+ * Copyright (C) 1994, 1996, 1998, 1999,
+ *               2000 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 <linux/string.h>
+#include "mpi-internal.h"
+#include "longlong.h"
+
+#define MPN_MUL_N_RECURSE(prodp, up, vp, size, tspace)		\
+	do {							\
+		if ((size) < KARATSUBA_THRESHOLD)		\
+			mul_n_basecase(prodp, up, vp, size);	\
+		else						\
+			mul_n(prodp, up, vp, size, tspace);	\
+	} while (0);
+
+#define MPN_SQR_N_RECURSE(prodp, up, size, tspace)		\
+	do {							\
+		if ((size) < KARATSUBA_THRESHOLD)		\
+			mpih_sqr_n_basecase(prodp, up, size);	\
+		else						\
+			mpih_sqr_n(prodp, up, size, tspace);	\
+	} while (0);
+
+/* Multiply the natural numbers u (pointed to by UP) and v (pointed to by VP),
+ * both with SIZE limbs, and store the result at PRODP.  2 * SIZE limbs are
+ * always stored.  Return the most significant limb.
+ *
+ * Argument constraints:
+ * 1. PRODP != UP and PRODP != VP, i.e. the destination
+ *    must be distinct from the multiplier and the multiplicand.
+ *
+ *
+ * Handle simple cases with traditional multiplication.
+ *
+ * This is the most critical code of multiplication.  All multiplies rely
+ * on this, both small and huge.  Small ones arrive here immediately.  Huge
+ * ones arrive here as this is the base case for Karatsuba's recursive
+ * algorithm below.
+ */
+
+static mpi_limb_t
+mul_n_basecase(mpi_ptr_t prodp, mpi_ptr_t up, mpi_ptr_t vp, mpi_size_t size)
+{
+	mpi_size_t i;
+	mpi_limb_t cy;
+	mpi_limb_t v_limb;
+
+	/* Multiply by the first limb in V separately, as the result can be
+	 * stored (not added) to PROD.  We also avoid a loop for zeroing.  */
+	v_limb = vp[0];
+	if (v_limb <= 1) {
+		if (v_limb == 1)
+			MPN_COPY(prodp, up, size);
+		else
+			MPN_ZERO(prodp, size);
+		cy = 0;
+	} else
+		cy = mpihelp_mul_1(prodp, up, size, v_limb);
+
+	prodp[size] = cy;
+	prodp++;
+
+	/* For each iteration in the outer loop, multiply one limb from
+	 * U with one limb from V, and add it to PROD.  */
+	for (i = 1; i < size; i++) {
+		v_limb = vp[i];
+		if (v_limb <= 1) {
+			cy = 0;
+			if (v_limb == 1)
+				cy = mpihelp_add_n(prodp, prodp, up, size);
+		} else
+			cy = mpihelp_addmul_1(prodp, up, size, v_limb);
+
+		prodp[size] = cy;
+		prodp++;
+	}
+
+	return cy;
+}
+
+static void
+mul_n(mpi_ptr_t prodp, mpi_ptr_t up, mpi_ptr_t vp,
+		mpi_size_t size, mpi_ptr_t tspace)
+{
+	if (size & 1) {
+		/* The size is odd, and the code below doesn't handle that.
+		 * Multiply the least significant (size - 1) limbs with a recursive
+		 * call, and handle the most significant limb of S1 and S2
+		 * separately.
+		 * A slightly faster way to do this would be to make the Karatsuba
+		 * code below behave as if the size were even, and let it check for
+		 * odd size in the end.  I.e., in essence move this code to the end.
+		 * Doing so would save us a recursive call, and potentially make the
+		 * stack grow a lot less.
+		 */
+		mpi_size_t esize = size - 1;	/* even size */
+		mpi_limb_t cy_limb;
+
+		MPN_MUL_N_RECURSE(prodp, up, vp, esize, tspace);
+		cy_limb = mpihelp_addmul_1(prodp + esize, up, esize, vp[esize]);
+		prodp[esize + esize] = cy_limb;
+		cy_limb = mpihelp_addmul_1(prodp + esize, vp, size, up[esize]);
+		prodp[esize + size] = cy_limb;
+	} else {
+		/* Anatolij Alekseevich Karatsuba's divide-and-conquer algorithm.
+		 *
+		 * Split U in two pieces, U1 and U0, such that
+		 * U = U0 + U1*(B**n),
+		 * and V in V1 and V0, such that
+		 * V = V0 + V1*(B**n).
+		 *
+		 * UV is then computed recursively using the identity
+		 *
+		 *        2n   n          n                     n
+		 * UV = (B  + B )U V  +  B (U -U )(V -V )  +  (B + 1)U V
+		 *                1 1        1  0   0  1              0 0
+		 *
+		 * Where B = 2**BITS_PER_MP_LIMB.
+		 */
+		mpi_size_t hsize = size >> 1;
+		mpi_limb_t cy;
+		int negflg;
+
+		/* Product H.      ________________  ________________
+		 *                |_____U1 x V1____||____U0 x V0_____|
+		 * Put result in upper part of PROD and pass low part of TSPACE
+		 * as new TSPACE.
+		 */
+		MPN_MUL_N_RECURSE(prodp + size, up + hsize, vp + hsize, hsize,
+				  tspace);
+
+		/* Product M.      ________________
+		 *                |_(U1-U0)(V0-V1)_|
+		 */
+		if (mpihelp_cmp(up + hsize, up, hsize) >= 0) {
+			mpihelp_sub_n(prodp, up + hsize, up, hsize);
+			negflg = 0;
+		} else {
+			mpihelp_sub_n(prodp, up, up + hsize, hsize);
+			negflg = 1;
+		}
+		if (mpihelp_cmp(vp + hsize, vp, hsize) >= 0) {
+			mpihelp_sub_n(prodp + hsize, vp + hsize, vp, hsize);
+			negflg ^= 1;
+		} else {
+			mpihelp_sub_n(prodp + hsize, vp, vp + hsize, hsize);
+			/* No change of NEGFLG.  */
+		}
+		/* Read temporary operands from low part of PROD.
+		 * Put result in low part of TSPACE using upper part of TSPACE
+		 * as new TSPACE.
+		 */
+		MPN_MUL_N_RECURSE(tspace, prodp, prodp + hsize, hsize,
+				  tspace + size);
+
+		/* Add/copy product H. */
+		MPN_COPY(prodp + hsize, prodp + size, hsize);
+		cy = mpihelp_add_n(prodp + size, prodp + size,
+				   prodp + size + hsize, hsize);
+
+		/* Add product M (if NEGFLG M is a negative number) */
+		if (negflg)
+			cy -=
+			    mpihelp_sub_n(prodp + hsize, prodp + hsize, tspace,
+					  size);
+		else
+			cy +=
+			    mpihelp_add_n(prodp + hsize, prodp + hsize, tspace,
+					  size);
+
+		/* Product L.      ________________  ________________
+		 *                |________________||____U0 x V0_____|
+		 * Read temporary operands from low part of PROD.
+		 * Put result in low part of TSPACE using upper part of TSPACE
+		 * as new TSPACE.
+		 */
+		MPN_MUL_N_RECURSE(tspace, up, vp, hsize, tspace + size);
+
+		/* Add/copy Product L (twice) */
+
+		cy += mpihelp_add_n(prodp + hsize, prodp + hsize, tspace, size);
+		if (cy)
+			mpihelp_add_1(prodp + hsize + size,
+				      prodp + hsize + size, hsize, cy);
+
+		MPN_COPY(prodp, tspace, hsize);
+		cy = mpihelp_add_n(prodp + hsize, prodp + hsize, tspace + hsize,
+				   hsize);
+		if (cy)
+			mpihelp_add_1(prodp + size, prodp + size, size, 1);
+	}
+}
+
+void mpih_sqr_n_basecase(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size)
+{
+	mpi_size_t i;
+	mpi_limb_t cy_limb;
+	mpi_limb_t v_limb;
+
+	/* Multiply by the first limb in V separately, as the result can be
+	 * stored (not added) to PROD.  We also avoid a loop for zeroing.  */
+	v_limb = up[0];
+	if (v_limb <= 1) {
+		if (v_limb == 1)
+			MPN_COPY(prodp, up, size);
+		else
+			MPN_ZERO(prodp, size);
+		cy_limb = 0;
+	} else
+		cy_limb = mpihelp_mul_1(prodp, up, size, v_limb);
+
+	prodp[size] = cy_limb;
+	prodp++;
+
+	/* For each iteration in the outer loop, multiply one limb from
+	 * U with one limb from V, and add it to PROD.  */
+	for (i = 1; i < size; i++) {
+		v_limb = up[i];
+		if (v_limb <= 1) {
+			cy_limb = 0;
+			if (v_limb == 1)
+				cy_limb = mpihelp_add_n(prodp, prodp, up, size);
+		} else
+			cy_limb = mpihelp_addmul_1(prodp, up, size, v_limb);
+
+		prodp[size] = cy_limb;
+		prodp++;
+	}
+}
+
+void
+mpih_sqr_n(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size, mpi_ptr_t tspace)
+{
+	if (size & 1) {
+		/* The size is odd, and the code below doesn't handle that.
+		 * Multiply the least significant (size - 1) limbs with a recursive
+		 * call, and handle the most significant limb of S1 and S2
+		 * separately.
+		 * A slightly faster way to do this would be to make the Karatsuba
+		 * code below behave as if the size were even, and let it check for
+		 * odd size in the end.  I.e., in essence move this code to the end.
+		 * Doing so would save us a recursive call, and potentially make the
+		 * stack grow a lot less.
+		 */
+		mpi_size_t esize = size - 1;	/* even size */
+		mpi_limb_t cy_limb;
+
+		MPN_SQR_N_RECURSE(prodp, up, esize, tspace);
+		cy_limb = mpihelp_addmul_1(prodp + esize, up, esize, up[esize]);
+		prodp[esize + esize] = cy_limb;
+		cy_limb = mpihelp_addmul_1(prodp + esize, up, size, up[esize]);
+
+		prodp[esize + size] = cy_limb;
+	} else {
+		mpi_size_t hsize = size >> 1;
+		mpi_limb_t cy;
+
+		/* Product H.      ________________  ________________
+		 *                |_____U1 x U1____||____U0 x U0_____|
+		 * Put result in upper part of PROD and pass low part of TSPACE
+		 * as new TSPACE.
+		 */
+		MPN_SQR_N_RECURSE(prodp + size, up + hsize, hsize, tspace);
+
+		/* Product M.      ________________
+		 *                |_(U1-U0)(U0-U1)_|
+		 */
+		if (mpihelp_cmp(up + hsize, up, hsize) >= 0)
+			mpihelp_sub_n(prodp, up + hsize, up, hsize);
+		else
+			mpihelp_sub_n(prodp, up, up + hsize, hsize);
+
+		/* Read temporary operands from low part of PROD.
+		 * Put result in low part of TSPACE using upper part of TSPACE
+		 * as new TSPACE.  */
+		MPN_SQR_N_RECURSE(tspace, prodp, hsize, tspace + size);
+
+		/* Add/copy product H  */
+		MPN_COPY(prodp + hsize, prodp + size, hsize);
+		cy = mpihelp_add_n(prodp + size, prodp + size,
+				   prodp + size + hsize, hsize);
+
+		/* Add product M (if NEGFLG M is a negative number).  */
+		cy -= mpihelp_sub_n(prodp + hsize, prodp + hsize, tspace, size);
+
+		/* Product L.      ________________  ________________
+		 *                |________________||____U0 x U0_____|
+		 * Read temporary operands from low part of PROD.
+		 * Put result in low part of TSPACE using upper part of TSPACE
+		 * as new TSPACE.  */
+		MPN_SQR_N_RECURSE(tspace, up, hsize, tspace + size);
+
+		/* Add/copy Product L (twice).  */
+		cy += mpihelp_add_n(prodp + hsize, prodp + hsize, tspace, size);
+		if (cy)
+			mpihelp_add_1(prodp + hsize + size,
+				      prodp + hsize + size, hsize, cy);
+
+		MPN_COPY(prodp, tspace, hsize);
+		cy = mpihelp_add_n(prodp + hsize, prodp + hsize, tspace + hsize,
+				   hsize);
+		if (cy)
+			mpihelp_add_1(prodp + size, prodp + size, size, 1);
+	}
+}
+
+int
+mpihelp_mul_karatsuba_case(mpi_ptr_t prodp,
+			   mpi_ptr_t up, mpi_size_t usize,
+			   mpi_ptr_t vp, mpi_size_t vsize,
+			   struct karatsuba_ctx *ctx)
+{
+	mpi_limb_t cy;
+
+	if (!ctx->tspace || ctx->tspace_size < vsize) {
+		if (ctx->tspace)
+			mpi_free_limb_space(ctx->tspace);
+		ctx->tspace = mpi_alloc_limb_space(2 * vsize);
+		if (!ctx->tspace)
+			return -ENOMEM;
+		ctx->tspace_size = vsize;
+	}
+
+	MPN_MUL_N_RECURSE(prodp, up, vp, vsize, ctx->tspace);
+
+	prodp += vsize;
+	up += vsize;
+	usize -= vsize;
+	if (usize >= vsize) {
+		if (!ctx->tp || ctx->tp_size < vsize) {
+			if (ctx->tp)
+				mpi_free_limb_space(ctx->tp);
+			ctx->tp = mpi_alloc_limb_space(2 * vsize);
+			if (!ctx->tp) {
+				if (ctx->tspace)
+					mpi_free_limb_space(ctx->tspace);
+				ctx->tspace = NULL;
+				return -ENOMEM;
+			}
+			ctx->tp_size = vsize;
+		}
+
+		do {
+			MPN_MUL_N_RECURSE(ctx->tp, up, vp, vsize, ctx->tspace);
+			cy = mpihelp_add_n(prodp, prodp, ctx->tp, vsize);
+			mpihelp_add_1(prodp + vsize, ctx->tp + vsize, vsize,
+				      cy);
+			prodp += vsize;
+			up += vsize;
+			usize -= vsize;
+		} while (usize >= vsize);
+	}
+
+	if (usize) {
+		if (usize < KARATSUBA_THRESHOLD) {
+			mpi_limb_t tmp;
+			if (mpihelp_mul(ctx->tspace, vp, vsize, up, usize, &tmp)
+			    < 0)
+				return -ENOMEM;
+		} else {
+			if (!ctx->next) {
+				ctx->next = kzalloc_obj(*ctx);
+				if (!ctx->next)
+					return -ENOMEM;
+			}
+			if (mpihelp_mul_karatsuba_case(ctx->tspace,
+						       vp, vsize,
+						       up, usize,
+						       ctx->next) < 0)
+				return -ENOMEM;
+		}
+
+		cy = mpihelp_add_n(prodp, prodp, ctx->tspace, vsize);
+		mpihelp_add_1(prodp + vsize, ctx->tspace + vsize, usize, cy);
+	}
+
+	return 0;
+}
+
+void mpihelp_release_karatsuba_ctx(struct karatsuba_ctx *ctx)
+{
+	struct karatsuba_ctx *ctx2;
+
+	if (ctx->tp)
+		mpi_free_limb_space(ctx->tp);
+	if (ctx->tspace)
+		mpi_free_limb_space(ctx->tspace);
+	for (ctx = ctx->next; ctx; ctx = ctx2) {
+		ctx2 = ctx->next;
+		if (ctx->tp)
+			mpi_free_limb_space(ctx->tp);
+		if (ctx->tspace)
+			mpi_free_limb_space(ctx->tspace);
+		kfree(ctx);
+	}
+}
+
+/* Multiply the natural numbers u (pointed to by UP, with USIZE limbs)
+ * and v (pointed to by VP, with VSIZE limbs), and store the result at
+ * PRODP.  USIZE + VSIZE limbs are always stored, but if the input
+ * operands are normalized.  Return the most significant limb of the
+ * result.
+ *
+ * NOTE: The space pointed to by PRODP is overwritten before finished
+ * with U and V, so overlap is an error.
+ *
+ * Argument constraints:
+ * 1. USIZE >= VSIZE.
+ * 2. PRODP != UP and PRODP != VP, i.e. the destination
+ *    must be distinct from the multiplier and the multiplicand.
+ */
+
+int
+mpihelp_mul(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t usize,
+	    mpi_ptr_t vp, mpi_size_t vsize, mpi_limb_t *_result)
+{
+	mpi_ptr_t prod_endp = prodp + usize + vsize - 1;
+	mpi_limb_t cy;
+	struct karatsuba_ctx ctx;
+
+	if (vsize < KARATSUBA_THRESHOLD) {
+		mpi_size_t i;
+		mpi_limb_t v_limb;
+
+		if (!vsize) {
+			*_result = 0;
+			return 0;
+		}
+
+		/* Multiply by the first limb in V separately, as the result can be
+		 * stored (not added) to PROD.  We also avoid a loop for zeroing.  */
+		v_limb = vp[0];
+		if (v_limb <= 1) {
+			if (v_limb == 1)
+				MPN_COPY(prodp, up, usize);
+			else
+				MPN_ZERO(prodp, usize);
+			cy = 0;
+		} else
+			cy = mpihelp_mul_1(prodp, up, usize, v_limb);
+
+		prodp[usize] = cy;
+		prodp++;
+
+		/* For each iteration in the outer loop, multiply one limb from
+		 * U with one limb from V, and add it to PROD.  */
+		for (i = 1; i < vsize; i++) {
+			v_limb = vp[i];
+			if (v_limb <= 1) {
+				cy = 0;
+				if (v_limb == 1)
+					cy = mpihelp_add_n(prodp, prodp, up,
+							   usize);
+			} else
+				cy = mpihelp_addmul_1(prodp, up, usize, v_limb);
+
+			prodp[usize] = cy;
+			prodp++;
+		}
+
+		*_result = cy;
+		return 0;
+	}
+
+	memset(&ctx, 0, sizeof ctx);
+	if (mpihelp_mul_karatsuba_case(prodp, up, usize, vp, vsize, &ctx) < 0)
+		return -ENOMEM;
+	mpihelp_release_karatsuba_ctx(&ctx);
+	*_result = *prod_endp;
+	return 0;
+}

linux-7.2.3/lib/crypto/mpi/mpiutil.c

@@ -0,0 +1,152 @@
+/* mpiutil.ac  -  Utility functions for MPI
+ * 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 <linux/export.h>
+
+#include "mpi-internal.h"
+
+/****************
+ * Note:  It was a bad idea to use the number of limbs to allocate
+ *	  because on a alpha the limbs are large but we normally need
+ *	  integers of n bits - So we should change this to bits (or bytes).
+ *
+ *	  But mpi_alloc is used in a lot of places :-)
+ */
+MPI mpi_alloc(unsigned nlimbs)
+{
+	MPI a;
+
+	a = kmalloc_obj(*a);
+	if (!a)
+		return a;
+
+	if (nlimbs) {
+		a->d = mpi_alloc_limb_space(nlimbs);
+		if (!a->d) {
+			kfree(a);
+			return NULL;
+		}
+	} else {
+		a->d = NULL;
+	}
+
+	a->alloced = nlimbs;
+	a->nlimbs = 0;
+	a->sign = 0;
+	a->flags = 0;
+	a->nbits = 0;
+	return a;
+}
+EXPORT_SYMBOL_GPL(mpi_alloc);
+
+mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs)
+{
+	size_t len = nlimbs * sizeof(mpi_limb_t);
+
+	if (!len)
+		return NULL;
+
+	return kmalloc(len, GFP_KERNEL);
+}
+
+void mpi_free_limb_space(mpi_ptr_t a)
+{
+	if (!a)
+		return;
+
+	kfree_sensitive(a);
+}
+
+void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
+{
+	mpi_free_limb_space(a->d);
+	a->d = ap;
+	a->alloced = nlimbs;
+}
+
+/****************
+ * Resize the array of A to NLIMBS. the additional space is cleared
+ * (set to 0) [done by m_realloc()]
+ */
+int mpi_resize(MPI a, unsigned nlimbs)
+{
+	void *p;
+
+	if (nlimbs <= a->alloced)
+		return 0;	/* no need to do it */
+
+	if (a->d) {
+		p = kzalloc_objs(mpi_limb_t, nlimbs);
+		if (!p)
+			return -ENOMEM;
+		memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
+		kfree_sensitive(a->d);
+		a->d = p;
+	} else {
+		a->d = kzalloc_objs(mpi_limb_t, nlimbs);
+		if (!a->d)
+			return -ENOMEM;
+	}
+	a->alloced = nlimbs;
+	return 0;
+}
+
+void mpi_free(MPI a)
+{
+	if (!a)
+		return;
+
+	if (a->flags & 4)
+		kfree_sensitive(a->d);
+	else
+		mpi_free_limb_space(a->d);
+
+	if (a->flags & ~7)
+		pr_info("invalid flag value in mpi\n");
+	kfree(a);
+}
+EXPORT_SYMBOL_GPL(mpi_free);
+
+/****************
+ * Note: This copy function should not interpret the MPI
+ *	 but copy it transparently.
+ */
+MPI mpi_copy(MPI a)
+{
+	int i;
+	MPI b;
+
+	if (a) {
+		b = mpi_alloc(a->nlimbs);
+		if (!b)
+			return NULL;
+		b->nlimbs = a->nlimbs;
+		b->sign = a->sign;
+		b->flags = a->flags;
+		b->flags &= ~(16|32); /* Reset the immutable and constant flags. */
+		for (i = 0; i < b->nlimbs; i++)
+			b->d[i] = a->d[i];
+	} else
+		b = NULL;
+	return b;
+}
+
+MODULE_DESCRIPTION("Multiprecision maths library");
+MODULE_LICENSE("GPL");