SecuritySNACCRuntime/c-lib/src/asn-len.c

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /*
  20  * asn_len.c - BER encode, decode and utilities for ASN.1 lengths.
  21  *
  22  *   indefinite lens are representd by the highest AsnLen
  23  *
  24  * MS 92
  25  * Copyright (C) 1992 Michael Sample and the University of British Columbia
  26  *
  27  * This library is free software; you can redistribute it and/or
  28  * modify it provided that this copyright/license information is retained
  29  * in original form.
  30  *
  31  * If you modify this file, you must clearly indicate your changes.
  32  *
  33  * This source code is distributed in the hope that it will be
  34  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  35  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  36  *
  37  * $Header: /cvs/Darwin/src/live/Security/SecuritySNACCRuntime/c-lib/src/asn-len.c,v 1.1.1.1 2001/05/18 23:14:08 mb Exp $
  38  * $Log: asn-len.c,v $
  39  * Revision 1.1.1.1  2001/05/18 23:14:08  mb
  40  * Move from private repository to open source repository
  41  *
  42  * Revision 1.2  2001/05/05 00:59:25  rmurphy
  43  * Adding darwin license headers
  44  *
  45  * Revision 1.1.1.1  1999/03/16 18:06:30  aram
  46  * Originals from SMIME Free Library.
  47  *
  48  * Revision 1.2  1995/07/27 08:58:36  rj
  49  * merged PeekEoc(), a function used only by the type table code.
  50  *
  51  * changed `_' to `-' in file names.
  52  *
  53  * Revision 1.1  1994/08/28  09:45:54  rj
  54  * first check-in. for a list of changes to the snacc-1.1 distribution please refer to the ChangeLog.
  55  *
  56  */
  57
  58 #include "asn-config.h"
  59 #include "asn-len.h"
  60
  61
  62 AsnLen
  63 BEncDefLen PARAMS ((b, len),
  64     BUF_TYPE b _AND_
  65     AsnLen len)
  66 {
  67     /*
  68      * unrolled for efficiency
  69      * check each possibitlity of the 4 byte integer
  70      */
  71     if (len < 128)
  72     {
  73         BufPutByteRvs (b, len);
  74         return 1;
  75     }
  76     else if (len < 256)
  77     {
  78         BufPutByteRvs (b, len);
  79         BufPutByteRvs (b, 0x81);
  80         return 2;
  81     }
  82     else if (len < 65536)
  83     {
  84         BufPutByteRvs (b, len);
  85         BufPutByteRvs (b, len >> 8);
  86         BufPutByteRvs (b, 0x82);
  87         return 3;
  88     }
  89     else if (len < 16777126)
  90     {
  91         BufPutByteRvs (b, len);
  92         BufPutByteRvs (b, len >> 8);
  93         BufPutByteRvs (b, len >> 16);
  94         BufPutByteRvs (b, 0x83);
  95         return 4;
  96     }
  97     else
  98     {
  99         BufPutByteRvs (b, len);
 100         BufPutByteRvs (b, len >> 8);
 101         BufPutByteRvs (b, len >> 16);
 102         BufPutByteRvs (b, len >> 24);
 103         BufPutByteRvs (b, 0x84);
 104         return 5;
 105     }
 106 } /*  BEncDefLen */
 107
 108
 109 /*
 110  * non unrolled version
 111  */
 112 AsnLen
 113 BEncDefLen2 PARAMS ((b, len),
 114     BUF_TYPE  b _AND_
 115     long int  len)
 116 {
 117     int i;
 118     unsigned long int j;
 119
 120     if (len < 128)
 121     {
 122         BufPutByteRvs (b, len);
 123         return 1;
 124     }
 125     else
 126     {
 127         for (i = 0, j = len; j > 0; j >>= 8, i++)
 128             BufPutByteRvs (b, j);
 129
 130         BufPutByteRvs (b, 0x80 | i);
 131         return i + 1;
 132     }
 133
 134 } /*  BEncDefLen2 */
 135
 136
 137 /*
 138  * decodes and returns an ASN.1 length
 139  */
 140 AsnLen
 141 BDecLen PARAMS ((b, bytesDecoded, env),
 142     BUF_TYPE b _AND_
 143     unsigned long int  *bytesDecoded _AND_
 144     jmp_buf env)
 145 {
 146     AsnLen len;
 147     AsnLen byte;
 148     int lenBytes;
 149
 150     byte = (unsigned long int) BufGetByte (b);
 151
 152     if (BufReadError (b))
 153     {
 154         Asn1Error ("BDecLen: ERROR - decoded past end of data\n");
 155         longjmp (env, -13);
 156     }
 157
 158     (*bytesDecoded)++;
 159     if (byte < 128)   /* short length */
 160         return byte;
 161
 162     else if (byte == (AsnLen) 0x080)  /* indef len indicator */
 163         return INDEFINITE_LEN;
 164
 165     else  /* long len form */
 166     {
 167         /*
 168          * strip high bit to get # bytes left in len
 169          */
 170         lenBytes = byte & (AsnLen) 0x7f;
 171
 172         if (lenBytes > sizeof (AsnLen))
 173         {
 174             Asn1Error ("BDecLen: ERROR - length overflow\n");
 175             longjmp (env, -14);
 176         }
 177
 178         (*bytesDecoded) += lenBytes;
 179
 180         for (len = 0; lenBytes > 0; lenBytes--)
 181             len = (len << 8) | (AsnLen) BufGetByte (b);
 182
 183
 184         if (BufReadError (b))
 185         {
 186             Asn1Error ("BDecLen: ERROR - decoded past end of data\n");
 187             longjmp (env, -15);
 188         }
 189
 190         return len;
 191     }
 192     /* not reached */
 193 } /* BDecLen */
 194
 195
 196 /* MACRO
 197 AsnLen
 198 BEncEoc PARAMS ((b),
 199     BUF_TYPE b)
 200 {
 201     BufPutByteRvs (b, 0);
 202     BufPutByteRvs (b, 0);
 203     return 2;
 204 }   BEncEoc */
 205
 206 /*
 207  * Decodes an End of Contents (EOC) marker from the given buffer.
 208  * Flags and error if the octets are non-zero or if a read error
 209  * occurs.  Increments bytesDecoded by the length of the EOC marker.
 210  */
 211 void
 212 BDecEoc PARAMS ((b, bytesDecoded, env),
 213     BUF_TYPE b _AND_
 214     AsnLen *bytesDecoded _AND_
 215     jmp_buf env)
 216 {
 217     if ((BufGetByte (b) != 0) || (BufGetByte (b) != 0) || BufReadError (b))
 218     {
 219         Asn1Error ("BDecEoc: ERROR - non zero byte in EOC or end of data reached\n");
 220         longjmp (env, -16);
 221     }
 222     (*bytesDecoded) += 2;
 223
 224 }  /* BDecEoc */
 225
 226 #if TTBL
 227 /* returns true if the next tag is actually and EOC */
 228 int PeekEoc PARAMS ((b),
 229     BUF_TYPE b)
 230 {
 231     return BufPeekByte (b) == 0;
 232 }  /* PeekEoc */
 233 #endif