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

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

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

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

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

Signed-off-by: Dmitry Kasatkin <[email protected]>

lib/Kconfig

@@ -283,4 +283,14 @@ config MPILIB
 	  It is used to implement RSA digital signature verification,
 	  which is used by IMA/EVM digital signature extension.
 
+config MPILIB_EXTRA
+	bool "Multiprecision maths library - additional sources"
+	depends on MPILIB
+	help
+	  Multiprecision maths library from GnuPG.
+	  It is used to implement RSA digital signature verification,
+	  which is used by IMA/EVM digital signature extension.
+	  This code in unnecessary for RSA digital signature verification,
+	  and can be compiled if needed.
+
 endmenu

lib/mpi/Makefile

@@ -19,3 +19,14 @@ mpi-y = \
 	mpih-mul.o			\
 	mpi-pow.o			\
 	mpiutil.o
+
+mpi-$(CONFIG_MPILIB_EXTRA) += \
+	mpi-add.o			\
+	mpi-div.o			\
+	mpi-cmp.o			\
+	mpi-gcd.o			\
+	mpi-inline.o			\
+	mpi-inv.o			\
+	mpi-mpow.o			\
+	mpi-mul.o			\
+	mpi-scan.o

lib/mpi/generic_mpi-asm-defs.h

@@ -0,0 +1,4 @@
+/* This file defines some basic constants for the MPI machinery.  We
+ * need to define the types on a per-CPU basis, so it is done with
+ * this file here.  */
+#define BYTES_PER_MPI_LIMB  (SIZEOF_UNSIGNED_LONG)

lib/mpi/mpi-add.c

@@ -0,0 +1,234 @@
+/* mpi-add.c  -  MPI functions
+ *	Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+ *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ *
+ * Note: This code is heavily based on the GNU MP Library.
+ *	 Actually it's the same code with only minor changes in the
+ *	 way the data is stored; this is to support the abstraction
+ *	 of an optional secure memory allocation which may be used
+ *	 to avoid revealing of sensitive data due to paging etc.
+ *	 The GNU MP Library itself is published under the LGPL;
+ *	 however I decided to publish this code under the plain GPL.
+ */
+
+#include "mpi-internal.h"
+
+/****************
+ * Add the unsigned integer V to the mpi-integer U and store the
+ * result in W. U and V may be the same.
+ */
+int mpi_add_ui(MPI w, const MPI u, unsigned long v)
+{
+	mpi_ptr_t wp, up;
+	mpi_size_t usize, wsize;
+	int usign, wsign;
+
+	usize = u->nlimbs;
+	usign = u->sign;
+	wsign = 0;
+
+	/* If not space for W (and possible carry), increase space.  */
+	wsize = usize + 1;
+	if (w->alloced < wsize)
+		if (mpi_resize(w, wsize) < 0)
+			return -ENOMEM;
+
+	/* These must be after realloc (U may be the same as W).  */
+	up = u->d;
+	wp = w->d;
+
+	if (!usize) {		/* simple */
+		wp[0] = v;
+		wsize = v ? 1 : 0;
+	} else if (!usign) {	/* mpi is not negative */
+		mpi_limb_t cy;
+		cy = mpihelp_add_1(wp, up, usize, v);
+		wp[usize] = cy;
+		wsize = usize + cy;
+	} else {		/* The signs are different.  Need exact comparison to determine
+				 * which operand to subtract from which.  */
+		if (usize == 1 && up[0] < v) {
+			wp[0] = v - up[0];
+			wsize = 1;
+		} else {
+			mpihelp_sub_1(wp, up, usize, v);
+			/* Size can decrease with at most one limb. */
+			wsize = usize - (wp[usize - 1] == 0);
+			wsign = 1;
+		}
+	}
+
+	w->nlimbs = wsize;
+	w->sign = wsign;
+	return 0;
+}
+
+int mpi_add(MPI w, MPI u, MPI v)
+{
+	mpi_ptr_t wp, up, vp;
+	mpi_size_t usize, vsize, wsize;
+	int usign, vsign, wsign;
+
+	if (u->nlimbs < v->nlimbs) {	/* Swap U and V. */
+		usize = v->nlimbs;
+		usign = v->sign;
+		vsize = u->nlimbs;
+		vsign = u->sign;
+		wsize = usize + 1;
+		if (RESIZE_IF_NEEDED(w, wsize) < 0)
+			return -ENOMEM;
+		/* These must be after realloc (u or v may be the same as w).  */
+		up = v->d;
+		vp = u->d;
+	} else {
+		usize = u->nlimbs;
+		usign = u->sign;
+		vsize = v->nlimbs;
+		vsign = v->sign;
+		wsize = usize + 1;
+		if (RESIZE_IF_NEEDED(w, wsize) < 0)
+			return -ENOMEM;
+		/* These must be after realloc (u or v may be the same as w).  */
+		up = u->d;
+		vp = v->d;
+	}
+	wp = w->d;
+	wsign = 0;
+
+	if (!vsize) {		/* simple */
+		MPN_COPY(wp, up, usize);
+		wsize = usize;
+		wsign = usign;
+	} else if (usign != vsign) {	/* different sign */
+		/* This test is right since USIZE >= VSIZE */
+		if (usize != vsize) {
+			mpihelp_sub(wp, up, usize, vp, vsize);
+			wsize = usize;
+			MPN_NORMALIZE(wp, wsize);
+			wsign = usign;
+		} else if (mpihelp_cmp(up, vp, usize) < 0) {
+			mpihelp_sub_n(wp, vp, up, usize);
+			wsize = usize;
+			MPN_NORMALIZE(wp, wsize);
+			if (!usign)
+				wsign = 1;
+		} else {
+			mpihelp_sub_n(wp, up, vp, usize);
+			wsize = usize;
+			MPN_NORMALIZE(wp, wsize);
+			if (usign)
+				wsign = 1;
+		}
+	} else {		/* U and V have same sign. Add them. */
+		mpi_limb_t cy = mpihelp_add(wp, up, usize, vp, vsize);
+		wp[usize] = cy;
+		wsize = usize + cy;
+		if (usign)
+			wsign = 1;
+	}
+
+	w->nlimbs = wsize;
+	w->sign = wsign;
+	return 0;
+}
+
+/****************
+ * Subtract the unsigned integer V from the mpi-integer U and store the
+ * result in W.
+ */
+int mpi_sub_ui(MPI w, MPI u, unsigned long v)
+{
+	mpi_ptr_t wp, up;
+	mpi_size_t usize, wsize;
+	int usign, wsign;
+
+	usize = u->nlimbs;
+	usign = u->sign;
+	wsign = 0;
+
+	/* If not space for W (and possible carry), increase space.  */
+	wsize = usize + 1;
+	if (w->alloced < wsize)
+		if (mpi_resize(w, wsize) < 0)
+			return -ENOMEM;
+
+	/* These must be after realloc (U may be the same as W).  */
+	up = u->d;
+	wp = w->d;
+
+	if (!usize) {		/* simple */
+		wp[0] = v;
+		wsize = v ? 1 : 0;
+		wsign = 1;
+	} else if (usign) {	/* mpi and v are negative */
+		mpi_limb_t cy;
+		cy = mpihelp_add_1(wp, up, usize, v);
+		wp[usize] = cy;
+		wsize = usize + cy;
+	} else {		/* The signs are different.  Need exact comparison to determine
+				 * which operand to subtract from which.  */
+		if (usize == 1 && up[0] < v) {
+			wp[0] = v - up[0];
+			wsize = 1;
+			wsign = 1;
+		} else {
+			mpihelp_sub_1(wp, up, usize, v);
+			/* Size can decrease with at most one limb. */
+			wsize = usize - (wp[usize - 1] == 0);
+		}
+	}
+
+	w->nlimbs = wsize;
+	w->sign = wsign;
+	return 0;
+}
+
+int mpi_sub(MPI w, MPI u, MPI v)
+{
+	int rc;
+
+	if (w == v) {
+		MPI vv;
+		if (mpi_copy(&vv, v) < 0)
+			return -ENOMEM;
+		vv->sign = !vv->sign;
+		rc = mpi_add(w, u, vv);
+		mpi_free(vv);
+	} else {
+		/* fixme: this is not thread-save (we temp. modify v) */
+		v->sign = !v->sign;
+		rc = mpi_add(w, u, v);
+		v->sign = !v->sign;
+	}
+	return rc;
+}
+
+int mpi_addm(MPI w, MPI u, MPI v, MPI m)
+{
+	if (mpi_add(w, u, v) < 0 || mpi_fdiv_r(w, w, m) < 0)
+		return -ENOMEM;
+	return 0;
+}
+
+int mpi_subm(MPI w, MPI u, MPI v, MPI m)
+{
+	if (mpi_sub(w, u, v) < 0 || mpi_fdiv_r(w, w, m) < 0)
+		return -ENOMEM;
+	return 0;
+}

lib/mpi/mpi-cmp.c

@@ -0,0 +1,68 @@
+/* mpi-cmp.c  -  MPI functions
+ * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "mpi-internal.h"
+
+int mpi_cmp_ui(MPI u, unsigned long v)
+{
+	mpi_limb_t limb = v;
+
+	mpi_normalize(u);
+	if (!u->nlimbs && !limb)
+		return 0;
+	if (u->sign)
+		return -1;
+	if (u->nlimbs > 1)
+		return 1;
+
+	if (u->d[0] == limb)
+		return 0;
+	else if (u->d[0] > limb)
+		return 1;
+	else
+		return -1;
+}
+
+int mpi_cmp(MPI u, MPI v)
+{
+	mpi_size_t usize, vsize;
+	int cmp;
+
+	mpi_normalize(u);
+	mpi_normalize(v);
+	usize = u->nlimbs;
+	vsize = v->nlimbs;
+	if (!u->sign && v->sign)
+		return 1;
+	if (u->sign && !v->sign)
+		return -1;
+	if (usize != vsize && !u->sign && !v->sign)
+		return usize - vsize;
+	if (usize != vsize && u->sign && v->sign)
+		return vsize + usize;
+	if (!usize)
+		return 0;
+	cmp = mpihelp_cmp(u->d, v->d, usize);
+	if (!cmp)
+		return 0;
+	if ((cmp < 0 ? 1 : 0) == (u->sign ? 1 : 0))
+		return 1;
+	return -1;
+}