Skip to content
Snippets Groups Projects
Select Git revision
11 results Searching

mpih-cmp.c

Blame
    • Dmitry Kasatkin's avatar
      cdec9cb5
      crypto: GnuPG based MPI lib - source files (part 1) · cdec9cb5
      Dmitry Kasatkin authored
      
      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: default avatarDmitry Kasatkin <dmitry.kasatkin@intel.com>
      cdec9cb5
      History
      crypto: GnuPG based MPI lib - source files (part 1)
      Dmitry Kasatkin authored
      
      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: default avatarDmitry Kasatkin <dmitry.kasatkin@intel.com>
    mpih-cmp.c 1.97 KiB
    /* mpihelp-sub.c  -  MPI helper functions
     *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
     *	Copyright (C) 1998, 1999, 2000, 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"
    
    /****************
     * Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
     * There are no restrictions on the relative sizes of
     * the two arguments.
     * Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.
     */
    int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size)
    {
    	mpi_size_t i;
    	mpi_limb_t op1_word, op2_word;
    
    	for (i = size - 1; i >= 0; i--) {
    		op1_word = op1_ptr[i];
    		op2_word = op2_ptr[i];
    		if (op1_word != op2_word)
    			goto diff;
    	}
    	return 0;
    
    diff:
    	/* This can *not* be simplified to
    	 *   op2_word - op2_word
    	 * since that expression might give signed overflow.  */
    	return (op1_word > op2_word) ? 1 : -1;
    }