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-mul.c b/lib/mpi/mpi-mul.c
new file mode 100644
index 0000000..1f3219e
--- /dev/null
+++ b/lib/mpi/mpi-mul.c
@@ -0,0 +1,194 @@
+/* mpi-mul.c - MPI functions
+ * Copyright (C) 1994, 1996 Free Software Foundation, Inc.
+ * Copyright (C) 1998, 2001 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"
+
+int mpi_mul_ui(MPI prod, MPI mult, unsigned long small_mult)
+{
+ mpi_size_t size, prod_size;
+ mpi_ptr_t prod_ptr;
+ mpi_limb_t cy;
+ int sign;
+
+ size = mult->nlimbs;
+ sign = mult->sign;
+
+ if (!size || !small_mult) {
+ prod->nlimbs = 0;
+ prod->sign = 0;
+ return 0;
+ }
+
+ prod_size = size + 1;
+ if (prod->alloced < prod_size)
+ if (mpi_resize(prod, prod_size) < 0)
+ return -ENOMEM;
+ prod_ptr = prod->d;
+
+ cy = mpihelp_mul_1(prod_ptr, mult->d, size, (mpi_limb_t) small_mult);
+ if (cy)
+ prod_ptr[size++] = cy;
+ prod->nlimbs = size;
+ prod->sign = sign;
+ return 0;
+}
+
+int mpi_mul_2exp(MPI w, MPI u, unsigned long cnt)
+{
+ mpi_size_t usize, wsize, limb_cnt;
+ mpi_ptr_t wp;
+ mpi_limb_t wlimb;
+ int usign, wsign;
+
+ usize = u->nlimbs;
+ usign = u->sign;
+
+ if (!usize) {
+ w->nlimbs = 0;
+ w->sign = 0;
+ return 0;
+ }
+
+ limb_cnt = cnt / BITS_PER_MPI_LIMB;
+ wsize = usize + limb_cnt + 1;
+ if (w->alloced < wsize)
+ if (mpi_resize(w, wsize) < 0)
+ return -ENOMEM;
+ wp = w->d;
+ wsize = usize + limb_cnt;
+ wsign = usign;
+
+ cnt %= BITS_PER_MPI_LIMB;
+ if (cnt) {
+ wlimb = mpihelp_lshift(wp + limb_cnt, u->d, usize, cnt);
+ if (wlimb) {
+ wp[wsize] = wlimb;
+ wsize++;
+ }
+ } else {
+ MPN_COPY_DECR(wp + limb_cnt, u->d, usize);
+ }
+
+ /* Zero all whole limbs at low end. Do it here and not before calling
+ * mpn_lshift, not to lose for U == W. */
+ MPN_ZERO(wp, limb_cnt);
+
+ w->nlimbs = wsize;
+ w->sign = wsign;
+ return 0;
+}
+
+int mpi_mul(MPI w, MPI u, MPI v)
+{
+ int rc = -ENOMEM;
+ 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;
+
+ 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 < (size_t) wsize) {
+ if (wp == up || wp == vp) {
+ wp = mpi_alloc_limb_space(wsize);
+ if (!wp)
+ goto nomem;
+ assign_wp = 1;
+ } else {
+ if (mpi_resize(w, wsize) < 0)
+ goto nomem;
+ 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)
+ goto nomem;
+ /* 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)
+ goto nomem;
+ /* Copy to the temporary space. */
+ MPN_COPY(vp, wp, vsize);
+ }
+ }
+
+ if (!vsize)
+ wsize = 0;
+ else {
+ if (mpihelp_mul(wp, up, usize, vp, vsize, &cy) < 0)
+ goto nomem;
+ wsize -= cy ? 0 : 1;
+ }
+
+ if (assign_wp)
+ mpi_assign_limb_space(w, wp, wsize);
+
+ w->nlimbs = wsize;
+ w->sign = sign_product;
+ rc = 0;
+nomem:
+ if (tmp_limb)
+ mpi_free_limb_space(tmp_limb);
+ return rc;
+}
+
+int mpi_mulm(MPI w, MPI u, MPI v, MPI m)
+{
+ if (mpi_mul(w, u, v) < 0)
+ return -ENOMEM;
+ return mpi_fdiv_r(w, w, m);
+}