crypto: GnuPG based MPI lib - header files (part 2)

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, 122 insertions, 0 deletions

diff --git a/lib/mpi/mpi-inline.h b/lib/mpi/mpi-inline.h
new file mode 100644
index 000000000000..e2b39852b30a
--- /dev/null
+++ b/lib/mpi/mpi-inline.h
@@ -0,0 +1,122 @@
+/* mpi-inline.h  -  Internal to the Multi Precision Integers
+ *      Copyright (C) 1994, 1996, 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
+ *
+ * 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.
+ */
+
+#ifndef G10_MPI_INLINE_H
+#define G10_MPI_INLINE_H
+
+#ifndef G10_MPI_INLINE_DECL
+#define G10_MPI_INLINE_DECL  extern inline
+#endif
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+              mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+        mpi_limb_t x;
+
+        x = *s1_ptr++;
+        s2_limb += x;
+        *res_ptr++ = s2_limb;
+        if (s2_limb < x) {      /* sum is less than the left operand: handle carry */
+                while (--s1_size) {
+                        x = *s1_ptr++ + 1;      /* add carry */
+                        *res_ptr++ = x; /* and store */
+                        if (x)  /* not 0 (no overflow): we can stop */
+                                goto leave;
+                }
+                return 1;       /* return carry (size of s1 to small) */
+        }
+
+leave:
+        if (res_ptr != s1_ptr) {        /* not the same variable */
+                mpi_size_t i;   /* copy the rest */
+                for (i = 0; i < s1_size - 1; i++)
+                        res_ptr[i] = s1_ptr[i];
+        }
+        return 0;               /* no carry */
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+            mpi_ptr_t s2_ptr, mpi_size_t s2_size)
+{
+        mpi_limb_t cy = 0;
+
+        if (s2_size)
+                cy = mpihelp_add_n(res_ptr, s1_ptr, s2_ptr, s2_size);
+
+        if (s1_size - s2_size)
+                cy = mpihelp_add_1(res_ptr + s2_size, s1_ptr + s2_size,
+                                   s1_size - s2_size, cy);
+        return cy;
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+              mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+        mpi_limb_t x;
+
+        x = *s1_ptr++;
+        s2_limb = x - s2_limb;
+        *res_ptr++ = s2_limb;
+        if (s2_limb > x) {
+                while (--s1_size) {
+                        x = *s1_ptr++;
+                        *res_ptr++ = x - 1;
+                        if (x)
+                                goto leave;
+                }
+                return 1;
+        }
+
+leave:
+        if (res_ptr != s1_ptr) {
+                mpi_size_t i;
+                for (i = 0; i < s1_size - 1; i++)
+                        res_ptr[i] = s1_ptr[i];
+        }
+        return 0;
+}
+
+G10_MPI_INLINE_DECL mpi_limb_t
+mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+            mpi_ptr_t s2_ptr, mpi_size_t s2_size)
+{
+        mpi_limb_t cy = 0;
+
+        if (s2_size)
+                cy = mpihelp_sub_n(res_ptr, s1_ptr, s2_ptr, s2_size);
+
+        if (s1_size - s2_size)
+                cy = mpihelp_sub_1(res_ptr + s2_size, s1_ptr + s2_size,
+                                   s1_size - s2_size, cy);
+        return cy;
+}
+
+#endif /*G10_MPI_INLINE_H */