keysize_descriptor.c

   1 /* keysize_descriptor.c */
   2 /*
   3     This file is part of the ARM-Crypto-Lib.
   4     Copyright (C) 2006-2010  Daniel Otte (daniel.otte@rub.de)
   5
   6     This program is free software: you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation, either version 3 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19 /**
  20  * \file    keysize_descriptor.c
  21  * \author  Daniel Otte
  22  * \email   daniel.otte@rub.de
  23  * \date    2009-01-07
  24  * \license GPLv3 or later
  25  */
  26
  27 #include <stdint.h>
  28 #include "keysize_descriptor.h"
  29
  30 uint8_t is_valid_keysize_P(const void* ks_desc, uint16_t keysize){
  31         uint8_t type;
  32         type = *((uint8_t*)ks_desc);
  33         ks_desc = (uint8_t*)ks_desc + 1;
  34         if(type==KS_TYPE_TERMINATOR)
  35                 return 0;
  36         if(type==KS_TYPE_LIST){
  37                 uint8_t items;
  38                 uint16_t item;
  39                 items = *((uint8_t*)ks_desc);
  40                 ks_desc = (uint8_t*)ks_desc + 1;
  41                 while(items--){
  42                         item = *((uint16_t*)ks_desc);
  43                         ks_desc = (uint8_t*)ks_desc + 2;
  44                         if(item==keysize)
  45                                 return 1;
  46                 }
  47                 ks_desc = (uint8_t*)ks_desc - 2;
  48         }
  49         if(type==KS_TYPE_RANGE){
  50                 uint16_t max, min;
  51                 min = *((uint16_t*)ks_desc);
  52                 ks_desc = (uint8_t*)ks_desc + 2;
  53                 max = *((uint16_t*)ks_desc);
  54                 if(min<=keysize && keysize<=max)
  55                         return 1;
  56         }
  57         if(type==KS_TYPE_ARG_RANGE){
  58                 uint16_t max, min, dist, offset;
  59                 min = *((uint16_t*)ks_desc);
  60                 ks_desc = (uint8_t*)ks_desc + 2;
  61                 max = *((uint16_t*)ks_desc);
  62                 ks_desc = (uint8_t*)ks_desc + 2;
  63                 dist = *((uint16_t*)ks_desc);
  64                 ks_desc = (uint8_t*)ks_desc + 2;
  65                 offset = *((uint16_t*)ks_desc);
  66                 if(min<=keysize && keysize<=max && (keysize%dist==offset))
  67                         return 1;
  68         }
  69         if(type>KS_TYPE_ARG_RANGE){
  70                 /* bad error, you may insert a big warning message here */
  71                 return 0;
  72         }
  73         return is_valid_keysize_P((uint8_t*)ks_desc+1, keysize); /* search the next record */
  74 }
  75
  76 uint16_t get_keysize(const void* ks_desc){
  77         uint8_t type;
  78         uint16_t keysize;
  79         type = *((uint8_t*)ks_desc);
  80         if(type==KS_TYPE_LIST)
  81                 ks_desc = (uint8_t*)ks_desc + 1;
  82         ks_desc = (uint8_t*)ks_desc + 1;
  83         keysize = *((uint16_t*)ks_desc);
  84         return keysize;
  85 }
  86
  87