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authorDmitry Kasatkin <dmitry.kasatkin@intel.com>2011-08-31 14:05:16 +0300
committerDmitry Kasatkin <dmitry.kasatkin@intel.com>2011-11-09 11:45:22 +0200
commitcdec9cb5167ab1113ba9c58e395f664d9d3f9acb (patch)
tree7d9a4ab3e86b937354d0151a24d412ea8d56ad43 /lib/mpi/generic_mpih-mul3.c
parent1ea6b8f48918282bdca0b32a34095504ee65bab5 (diff)
downloadlinux-linaro-stable-cdec9cb5167ab1113ba9c58e395f664d9d3f9acb.tar.gz
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>
Diffstat (limited to 'lib/mpi/generic_mpih-mul3.c')
-rw-r--r--lib/mpi/generic_mpih-mul3.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/lib/mpi/generic_mpih-mul3.c b/lib/mpi/generic_mpih-mul3.c
new file mode 100644
index 000000000000..f96df327be63
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+++ b/lib/mpi/generic_mpih-mul3.c
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+/* mpihelp-mul_3.c - MPI helper functions
+ * Copyright (C) 1994, 1996, 1997, 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"
+#include "longlong.h"
+
+mpi_limb_t
+mpihelp_submul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+ mpi_size_t s1_size, mpi_limb_t s2_limb)
+{
+ mpi_limb_t cy_limb;
+ mpi_size_t j;
+ mpi_limb_t prod_high, prod_low;
+ mpi_limb_t x;
+
+ /* The loop counter and index J goes from -SIZE to -1. This way
+ * the loop becomes faster. */
+ j = -s1_size;
+ res_ptr -= j;
+ s1_ptr -= j;
+
+ cy_limb = 0;
+ do {
+ umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
+
+ prod_low += cy_limb;
+ cy_limb = (prod_low < cy_limb ? 1 : 0) + prod_high;
+
+ x = res_ptr[j];
+ prod_low = x - prod_low;
+ cy_limb += prod_low > x ? 1 : 0;
+ res_ptr[j] = prod_low;
+ } while (++j);
+
+ return cy_limb;
+}