git.zerfleddert.de Git - proxmark3-svn/blob - common/mbedtls/asn1write.c

   1 /*
   2  * ASN.1 buffer writing functionality
   3  *
   4  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   5  *  SPDX-License-Identifier: GPL-2.0
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License along
  18  *  with this program; if not, write to the Free Software Foundation, Inc.,
  19  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  *  This file is part of mbed TLS (https://tls.mbed.org)
  22  */
  23
  24 #if !defined(MBEDTLS_CONFIG_FILE)
  25 #include "mbedtls/config.h"
  26 #else
  27 #include MBEDTLS_CONFIG_FILE
  28 #endif
  29
  30 #if defined(MBEDTLS_ASN1_WRITE_C)
  31
  32 #include "mbedtls/asn1write.h"
  33
  34 #include <string.h>
  35
  36 #if defined(MBEDTLS_PLATFORM_C)
  37 #include "mbedtls/platform.h"
  38 #else
  39 #include <stdlib.h>
  40 #define mbedtls_calloc    calloc
  41 #define mbedtls_free       free
  42 #endif
  43
  44 int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len )
  45 {
  46     if( len < 0x80 )
  47     {
  48         if( *p - start < 1 )
  49             return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
  50
  51         *--(*p) = (unsigned char) len;
  52         return( 1 );
  53     }
  54
  55     if( len <= 0xFF )
  56     {
  57         if( *p - start < 2 )
  58             return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
  59
  60         *--(*p) = (unsigned char) len;
  61         *--(*p) = 0x81;
  62         return( 2 );
  63     }
  64
  65     if( len <= 0xFFFF )
  66     {
  67         if( *p - start < 3 )
  68             return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
  69
  70         *--(*p) = ( len       ) & 0xFF;
  71         *--(*p) = ( len >>  8 ) & 0xFF;
  72         *--(*p) = 0x82;
  73         return( 3 );
  74     }
  75
  76     if( len <= 0xFFFFFF )
  77     {
  78         if( *p - start < 4 )
  79             return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
  80
  81         *--(*p) = ( len       ) & 0xFF;
  82         *--(*p) = ( len >>  8 ) & 0xFF;
  83         *--(*p) = ( len >> 16 ) & 0xFF;
  84         *--(*p) = 0x83;
  85         return( 4 );
  86     }
  87
  88 #if SIZE_MAX > 0xFFFFFFFF
  89     if( len <= 0xFFFFFFFF )
  90 #endif
  91     {
  92         if( *p - start < 5 )
  93             return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
  94
  95         *--(*p) = ( len       ) & 0xFF;
  96         *--(*p) = ( len >>  8 ) & 0xFF;
  97         *--(*p) = ( len >> 16 ) & 0xFF;
  98         *--(*p) = ( len >> 24 ) & 0xFF;
  99         *--(*p) = 0x84;
 100         return( 5 );
 101     }
 102
 103 #if SIZE_MAX > 0xFFFFFFFF
 104     return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
 105 #endif
 106 }
 107
 108 int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )
 109 {
 110     if( *p - start < 1 )
 111         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 112
 113     *--(*p) = tag;
 114
 115     return( 1 );
 116 }
 117
 118 int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start,
 119                            const unsigned char *buf, size_t size )
 120 {
 121     size_t len = 0;
 122
 123     if( *p < start || (size_t)( *p - start ) < size )
 124         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 125
 126     len = size;
 127     (*p) -= len;
 128     memcpy( *p, buf, len );
 129
 130     return( (int) len );
 131 }
 132
 133 #if defined(MBEDTLS_BIGNUM_C)
 134 int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start, const mbedtls_mpi *X )
 135 {
 136     int ret;
 137     size_t len = 0;
 138
 139     // Write the MPI
 140     //
 141     len = mbedtls_mpi_size( X );
 142
 143     if( *p < start || (size_t)( *p - start ) < len )
 144         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 145
 146     (*p) -= len;
 147     MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( X, *p, len ) );
 148
 149     // DER format assumes 2s complement for numbers, so the leftmost bit
 150     // should be 0 for positive numbers and 1 for negative numbers.
 151     //
 152     if( X->s ==1 && **p & 0x80 )
 153     {
 154         if( *p - start < 1 )
 155             return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 156
 157         *--(*p) = 0x00;
 158         len += 1;
 159     }
 160
 161     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 162     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
 163
 164     ret = (int) len;
 165
 166 cleanup:
 167     return( ret );
 168 }
 169 #endif /* MBEDTLS_BIGNUM_C */
 170
 171 int mbedtls_asn1_write_null( unsigned char **p, unsigned char *start )
 172 {
 173     int ret;
 174     size_t len = 0;
 175
 176     // Write NULL
 177     //
 178     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, 0) );
 179     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_NULL ) );
 180
 181     return( (int) len );
 182 }
 183
 184 int mbedtls_asn1_write_oid( unsigned char **p, unsigned char *start,
 185                     const char *oid, size_t oid_len )
 186 {
 187     int ret;
 188     size_t len = 0;
 189
 190     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
 191                                   (const unsigned char *) oid, oid_len ) );
 192     MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_len( p, start, len ) );
 193     MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OID ) );
 194
 195     return( (int) len );
 196 }
 197
 198 int mbedtls_asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start,
 199                                      const char *oid, size_t oid_len,
 200                                      size_t par_len )
 201 {
 202     int ret;
 203     size_t len = 0;
 204
 205     if( par_len == 0 )
 206         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_null( p, start ) );
 207     else
 208         len += par_len;
 209
 210     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) );
 211
 212     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 213     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
 214                                        MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
 215
 216     return( (int) len );
 217 }
 218
 219 int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start, int boolean )
 220 {
 221     int ret;
 222     size_t len = 0;
 223
 224     if( *p - start < 1 )
 225         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 226
 227     *--(*p) = (boolean) ? 255 : 0;
 228     len++;
 229
 230     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 231     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BOOLEAN ) );
 232
 233     return( (int) len );
 234 }
 235
 236 int mbedtls_asn1_write_int( unsigned char **p, unsigned char *start, int val )
 237 {
 238     int ret;
 239     size_t len = 0;
 240
 241     if( *p - start < 1 )
 242         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 243
 244     len += 1;
 245     *--(*p) = val;
 246
 247     if( val > 0 && **p & 0x80 )
 248     {
 249         if( *p - start < 1 )
 250             return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 251
 252         *--(*p) = 0x00;
 253         len += 1;
 254     }
 255
 256     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 257     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
 258
 259     return( (int) len );
 260 }
 261
 262 int mbedtls_asn1_write_printable_string( unsigned char **p, unsigned char *start,
 263                                  const char *text, size_t text_len )
 264 {
 265     int ret;
 266     size_t len = 0;
 267
 268     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
 269                   (const unsigned char *) text, text_len ) );
 270
 271     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 272     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_PRINTABLE_STRING ) );
 273
 274     return( (int) len );
 275 }
 276
 277 int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start,
 278                            const char *text, size_t text_len )
 279 {
 280     int ret;
 281     size_t len = 0;
 282
 283     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
 284                   (const unsigned char *) text, text_len ) );
 285
 286     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 287     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_IA5_STRING ) );
 288
 289     return( (int) len );
 290 }
 291
 292 int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start,
 293                           const unsigned char *buf, size_t bits )
 294 {
 295     int ret;
 296     size_t len = 0, size;
 297
 298     size = ( bits / 8 ) + ( ( bits % 8 ) ? 1 : 0 );
 299
 300     // Calculate byte length
 301     //
 302     if( *p < start || (size_t)( *p - start ) < size + 1 )
 303         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 304
 305     len = size + 1;
 306     (*p) -= size;
 307     memcpy( *p, buf, size );
 308
 309     // Write unused bits
 310     //
 311     *--(*p) = (unsigned char) (size * 8 - bits);
 312
 313     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 314     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BIT_STRING ) );
 315
 316     return( (int) len );
 317 }
 318
 319 int mbedtls_asn1_write_octet_string( unsigned char **p, unsigned char *start,
 320                              const unsigned char *buf, size_t size )
 321 {
 322     int ret;
 323     size_t len = 0;
 324
 325     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, buf, size ) );
 326
 327     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
 328     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OCTET_STRING ) );
 329
 330     return( (int) len );
 331 }
 332
 333 mbedtls_asn1_named_data *mbedtls_asn1_store_named_data( mbedtls_asn1_named_data **head,
 334                                         const char *oid, size_t oid_len,
 335                                         const unsigned char *val,
 336                                         size_t val_len )
 337 {
 338     mbedtls_asn1_named_data *cur;
 339
 340     if( ( cur = mbedtls_asn1_find_named_data( *head, oid, oid_len ) ) == NULL )
 341     {
 342         // Add new entry if not present yet based on OID
 343         //
 344         cur = (mbedtls_asn1_named_data*)mbedtls_calloc( 1,
 345                                             sizeof(mbedtls_asn1_named_data) );
 346         if( cur == NULL )
 347             return( NULL );
 348
 349         cur->oid.len = oid_len;
 350         cur->oid.p = mbedtls_calloc( 1, oid_len );
 351         if( cur->oid.p == NULL )
 352         {
 353             mbedtls_free( cur );
 354             return( NULL );
 355         }
 356
 357         memcpy( cur->oid.p, oid, oid_len );
 358
 359         cur->val.len = val_len;
 360         cur->val.p = mbedtls_calloc( 1, val_len );
 361         if( cur->val.p == NULL )
 362         {
 363             mbedtls_free( cur->oid.p );
 364             mbedtls_free( cur );
 365             return( NULL );
 366         }
 367
 368         cur->next = *head;
 369         *head = cur;
 370     }
 371     else if( cur->val.len < val_len )
 372     {
 373         /*
 374          * Enlarge existing value buffer if needed
 375          * Preserve old data until the allocation succeeded, to leave list in
 376          * a consistent state in case allocation fails.
 377          */
 378         void *p = mbedtls_calloc( 1, val_len );
 379         if( p == NULL )
 380             return( NULL );
 381
 382         mbedtls_free( cur->val.p );
 383         cur->val.p = p;
 384         cur->val.len = val_len;
 385     }
 386
 387     if( val != NULL )
 388         memcpy( cur->val.p, val, val_len );
 389
 390     return( cur );
 391 }
 392 #endif /* MBEDTLS_ASN1_WRITE_C */