crypto: GnuPG based MPI lib - source files (part 1)

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.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

1 files changed, 208 insertions, 0 deletions

diff --git a/lib/mpi/mpiutil.c b/lib/mpi/mpiutil.c
new file mode 100644
index 000000000000..eefc55d6b7f5
--- /dev/null
+++ b/lib/mpi/mpiutil.c
@@ -0,0 +1,208 @@
+/* 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 "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 chnage this to bits (or bytes).
+ *
+ *        But mpi_alloc is used in a lot of places :-)
+ */
+MPI mpi_alloc(unsigned nlimbs)
+{
+        MPI a;
+
+        a = kmalloc(sizeof *a, GFP_KERNEL);
+        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);
+
+        return kmalloc(len, GFP_KERNEL);
+}
+
+void mpi_free_limb_space(mpi_ptr_t a)
+{
+        if (!a)
+                return;
+
+        kfree(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 = kmalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
+                if (!p)
+                        return -ENOMEM;
+                memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
+                kfree(a->d);
+                a->d = p;
+        } else {
+                a->d = kzalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
+                if (!a->d)
+                        return -ENOMEM;
+        }
+        a->alloced = nlimbs;
+        return 0;
+}
+
+void mpi_clear(MPI a)
+{
+        a->nlimbs = 0;
+        a->nbits = 0;
+        a->flags = 0;
+}
+
+void mpi_free(MPI a)
+{
+        if (!a)
+                return;
+
+        if (a->flags & 4)
+                kfree(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.
+ */
+int mpi_copy(MPI *copied, const MPI a)
+{
+        size_t i;
+        MPI b;
+
+        *copied = MPI_NULL;
+
+        if (a) {
+                b = mpi_alloc(a->nlimbs);
+                if (!b)
+                        return -ENOMEM;
+
+                b->nlimbs = a->nlimbs;
+                b->sign = a->sign;
+                b->flags = a->flags;
+                b->nbits = a->nbits;
+
+                for (i = 0; i < b->nlimbs; i++)
+                        b->d[i] = a->d[i];
+
+                *copied = b;
+        }
+
+        return 0;
+}
+
+int mpi_set(MPI w, const MPI u)
+{
+        mpi_ptr_t wp, up;
+        mpi_size_t usize = u->nlimbs;
+        int usign = u->sign;
+
+        if (RESIZE_IF_NEEDED(w, (size_t) usize) < 0)
+                return -ENOMEM;
+
+        wp = w->d;
+        up = u->d;
+        MPN_COPY(wp, up, usize);
+        w->nlimbs = usize;
+        w->nbits = u->nbits;
+        w->flags = u->flags;
+        w->sign = usign;
+        return 0;
+}
+
+int mpi_set_ui(MPI w, unsigned long u)
+{
+        if (RESIZE_IF_NEEDED(w, 1) < 0)
+                return -ENOMEM;
+        w->d[0] = u;
+        w->nlimbs = u ? 1 : 0;
+        w->sign = 0;
+        w->nbits = 0;
+        w->flags = 0;
+        return 0;
+}
+
+MPI mpi_alloc_set_ui(unsigned long u)
+{
+        MPI w = mpi_alloc(1);
+        if (!w)
+                return w;
+        w->d[0] = u;
+        w->nlimbs = u ? 1 : 0;
+        w->sign = 0;
+        return w;
+}
+
+void mpi_swap(MPI a, MPI b)
+{
+        struct gcry_mpi tmp;
+
+        tmp = *a;
+        *a = *b;
+        *b = tmp;
+}