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>

1 files changed, 68 insertions, 0 deletions

diff --git a/lib/mpi/mpi-cmp.c b/lib/mpi/mpi-cmp.c
new file mode 100644
index 000000000000..914bc42a8a80
--- /dev/null
+++ b/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;
+}