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https://github.com/torvalds/linux
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cdec9cb516
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>
56 lines
2 KiB
C
56 lines
2 KiB
C
/* mpihelp-sub.c - MPI helper functions
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* Copyright (C) 1994, 1996 Free Software Foundation, Inc.
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* Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*
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* Note: This code is heavily based on the GNU MP Library.
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* Actually it's the same code with only minor changes in the
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* way the data is stored; this is to support the abstraction
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* of an optional secure memory allocation which may be used
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* to avoid revealing of sensitive data due to paging etc.
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* The GNU MP Library itself is published under the LGPL;
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* however I decided to publish this code under the plain GPL.
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*/
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#include "mpi-internal.h"
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/****************
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* Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
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* There are no restrictions on the relative sizes of
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* the two arguments.
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* Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.
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*/
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int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size)
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{
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mpi_size_t i;
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mpi_limb_t op1_word, op2_word;
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for (i = size - 1; i >= 0; i--) {
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op1_word = op1_ptr[i];
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op2_word = op2_ptr[i];
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if (op1_word != op2_word)
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goto diff;
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}
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return 0;
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diff:
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/* This can *not* be simplified to
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* op2_word - op2_word
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* since that expression might give signed overflow. */
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return (op1_word > op2_word) ? 1 : -1;
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}
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