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 <dmitry.kasatkin@intel.com>
diff --git a/lib/mpi/mpi-add.c b/lib/mpi/mpi-add.c
new file mode 100644
index 0000000..f56b9ba
--- /dev/null
+++ b/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;
+}