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   1 /**
   2  * \file asn1.h
   3  *
   4  * \brief Generic ASN.1 parsing
   5  */
   6 /*
   7  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   8  *  SPDX-License-Identifier: GPL-2.0
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  *
  24  *  This file is part of mbed TLS (https://tls.mbed.org)
  25  */
  26 #ifndef MBEDTLS_ASN1_H
  27 #define MBEDTLS_ASN1_H
  28
  29 #if !defined(MBEDTLS_CONFIG_FILE)
  30 #include "config.h"
  31 #else
  32 #include MBEDTLS_CONFIG_FILE
  33 #endif
  34
  35 #include <stddef.h>
  36
  37 #if defined(MBEDTLS_BIGNUM_C)
  38 #include "bignum.h"
  39 #endif
  40
  41 /**
  42  * \addtogroup asn1_module
  43  * \{
  44  */
  45
  46 /**
  47  * \name ASN1 Error codes
  48  * These error codes are OR'ed to X509 error codes for
  49  * higher error granularity.
  50  * ASN1 is a standard to specify data structures.
  51  * \{
  52  */
  53 #define MBEDTLS_ERR_ASN1_OUT_OF_DATA                      -0x0060  /**< Out of data when parsing an ASN1 data structure. */
  54 #define MBEDTLS_ERR_ASN1_UNEXPECTED_TAG                   -0x0062  /**< ASN1 tag was of an unexpected value. */
  55 #define MBEDTLS_ERR_ASN1_INVALID_LENGTH                   -0x0064  /**< Error when trying to determine the length or invalid length. */
  56 #define MBEDTLS_ERR_ASN1_LENGTH_MISMATCH                  -0x0066  /**< Actual length differs from expected length. */
  57 #define MBEDTLS_ERR_ASN1_INVALID_DATA                     -0x0068  /**< Data is invalid. (not used) */
  58 #define MBEDTLS_ERR_ASN1_ALLOC_FAILED                     -0x006A  /**< Memory allocation failed */
  59 #define MBEDTLS_ERR_ASN1_BUF_TOO_SMALL                    -0x006C  /**< Buffer too small when writing ASN.1 data structure. */
  60
  61 /* \} name */
  62
  63 /**
  64  * \name DER constants
  65  * These constants comply with the DER encoded ASN.1 type tags.
  66  * DER encoding uses hexadecimal representation.
  67  * An example DER sequence is:\n
  68  * - 0x02 -- tag indicating INTEGER
  69  * - 0x01 -- length in octets
  70  * - 0x05 -- value
  71  * Such sequences are typically read into \c ::mbedtls_x509_buf.
  72  * \{
  73  */
  74 #define MBEDTLS_ASN1_BOOLEAN                 0x01
  75 #define MBEDTLS_ASN1_INTEGER                 0x02
  76 #define MBEDTLS_ASN1_BIT_STRING              0x03
  77 #define MBEDTLS_ASN1_OCTET_STRING            0x04
  78 #define MBEDTLS_ASN1_NULL                    0x05
  79 #define MBEDTLS_ASN1_OID                     0x06
  80 #define MBEDTLS_ASN1_UTF8_STRING             0x0C
  81 #define MBEDTLS_ASN1_SEQUENCE                0x10
  82 #define MBEDTLS_ASN1_SET                     0x11
  83 #define MBEDTLS_ASN1_PRINTABLE_STRING        0x13
  84 #define MBEDTLS_ASN1_T61_STRING              0x14
  85 #define MBEDTLS_ASN1_IA5_STRING              0x16
  86 #define MBEDTLS_ASN1_UTC_TIME                0x17
  87 #define MBEDTLS_ASN1_GENERALIZED_TIME        0x18
  88 #define MBEDTLS_ASN1_UNIVERSAL_STRING        0x1C
  89 #define MBEDTLS_ASN1_BMP_STRING              0x1E
  90 #define MBEDTLS_ASN1_PRIMITIVE               0x00
  91 #define MBEDTLS_ASN1_CONSTRUCTED             0x20
  92 #define MBEDTLS_ASN1_CONTEXT_SPECIFIC        0x80
  93
  94 /*
  95  * Bit masks for each of the components of an ASN.1 tag as specified in
  96  * ITU X.690 (08/2015), section 8.1 "General rules for encoding",
  97  * paragraph 8.1.2.2:
  98  *
  99  * Bit  8     7   6   5          1
 100  *     +-------+-----+------------+
 101  *     | Class | P/C | Tag number |
 102  *     +-------+-----+------------+
 103  */
 104 #define MBEDTLS_ASN1_TAG_CLASS_MASK          0xC0
 105 #define MBEDTLS_ASN1_TAG_PC_MASK             0x20
 106 #define MBEDTLS_ASN1_TAG_VALUE_MASK          0x1F
 107
 108 /* \} name */
 109 /* \} addtogroup asn1_module */
 110
 111 /** Returns the size of the binary string, without the trailing \\0 */
 112 #define MBEDTLS_OID_SIZE(x) (sizeof(x) - 1)
 113
 114 /**
 115  * Compares an mbedtls_asn1_buf structure to a reference OID.
 116  *
 117  * Only works for 'defined' oid_str values (MBEDTLS_OID_HMAC_SHA1), you cannot use a
 118  * 'unsigned char *oid' here!
 119  */
 120 #define MBEDTLS_OID_CMP(oid_str, oid_buf)                                   \
 121         ( ( MBEDTLS_OID_SIZE(oid_str) != (oid_buf)->len ) ||                \
 122           memcmp( (oid_str), (oid_buf)->p, (oid_buf)->len) != 0 )
 123
 124 #ifdef __cplusplus
 125 extern "C" {
 126 #endif
 127
 128 /**
 129  * \name Functions to parse ASN.1 data structures
 130  * \{
 131  */
 132
 133 /**
 134  * Type-length-value structure that allows for ASN1 using DER.
 135  */
 136 typedef struct mbedtls_asn1_buf
 137 {
 138     int tag;                /**< ASN1 type, e.g. MBEDTLS_ASN1_UTF8_STRING. */
 139     size_t len;             /**< ASN1 length, in octets. */
 140     unsigned char *p;       /**< ASN1 data, e.g. in ASCII. */
 141 }
 142 mbedtls_asn1_buf;
 143
 144 /**
 145  * Container for ASN1 bit strings.
 146  */
 147 typedef struct mbedtls_asn1_bitstring
 148 {
 149     size_t len;                 /**< ASN1 length, in octets. */
 150     unsigned char unused_bits;  /**< Number of unused bits at the end of the string */
 151     unsigned char *p;           /**< Raw ASN1 data for the bit string */
 152 }
 153 mbedtls_asn1_bitstring;
 154
 155 /**
 156  * Container for a sequence of ASN.1 items
 157  */
 158 typedef struct mbedtls_asn1_sequence
 159 {
 160     mbedtls_asn1_buf buf;                   /**< Buffer containing the given ASN.1 item. */
 161     struct mbedtls_asn1_sequence *next;    /**< The next entry in the sequence. */
 162 }
 163 mbedtls_asn1_sequence;
 164
 165 /**
 166  * Container for a sequence or list of 'named' ASN.1 data items
 167  */
 168 typedef struct mbedtls_asn1_named_data
 169 {
 170     mbedtls_asn1_buf oid;                   /**< The object identifier. */
 171     mbedtls_asn1_buf val;                   /**< The named value. */
 172     struct mbedtls_asn1_named_data *next;  /**< The next entry in the sequence. */
 173     unsigned char next_merged;      /**< Merge next item into the current one? */
 174 }
 175 mbedtls_asn1_named_data;
 176
 177 /**
 178  * \brief       Get the length of an ASN.1 element.
 179  *              Updates the pointer to immediately behind the length.
 180  *
 181  * \param p     The position in the ASN.1 data
 182  * \param end   End of data
 183  * \param len   The variable that will receive the value
 184  *
 185  * \return      0 if successful, MBEDTLS_ERR_ASN1_OUT_OF_DATA on reaching
 186  *              end of data, MBEDTLS_ERR_ASN1_INVALID_LENGTH if length is
 187  *              unparseable.
 188  */
 189 int mbedtls_asn1_get_len( unsigned char **p,
 190                   const unsigned char *end,
 191                   size_t *len );
 192
 193 /**
 194  * \brief       Get the tag and length of the tag. Check for the requested tag.
 195  *              Updates the pointer to immediately behind the tag and length.
 196  *
 197  * \param p     The position in the ASN.1 data
 198  * \param end   End of data
 199  * \param len   The variable that will receive the length
 200  * \param tag   The expected tag
 201  *
 202  * \return      0 if successful, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if tag did
 203  *              not match requested tag, or another specific ASN.1 error code.
 204  */
 205 int mbedtls_asn1_get_tag( unsigned char **p,
 206                   const unsigned char *end,
 207                   size_t *len, int tag );
 208
 209 /**
 210  * \brief       Retrieve a boolean ASN.1 tag and its value.
 211  *              Updates the pointer to immediately behind the full tag.
 212  *
 213  * \param p     The position in the ASN.1 data
 214  * \param end   End of data
 215  * \param val   The variable that will receive the value
 216  *
 217  * \return      0 if successful or a specific ASN.1 error code.
 218  */
 219 int mbedtls_asn1_get_bool( unsigned char **p,
 220                    const unsigned char *end,
 221                    int *val );
 222
 223 /**
 224  * \brief       Retrieve an integer ASN.1 tag and its value.
 225  *              Updates the pointer to immediately behind the full tag.
 226  *
 227  * \param p     The position in the ASN.1 data
 228  * \param end   End of data
 229  * \param val   The variable that will receive the value
 230  *
 231  * \return      0 if successful or a specific ASN.1 error code.
 232  */
 233 int mbedtls_asn1_get_int( unsigned char **p,
 234                   const unsigned char *end,
 235                   int *val );
 236
 237 /**
 238  * \brief       Retrieve a bitstring ASN.1 tag and its value.
 239  *              Updates the pointer to immediately behind the full tag.
 240  *
 241  * \param p     The position in the ASN.1 data
 242  * \param end   End of data
 243  * \param bs    The variable that will receive the value
 244  *
 245  * \return      0 if successful or a specific ASN.1 error code.
 246  */
 247 int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end,
 248                         mbedtls_asn1_bitstring *bs);
 249
 250 /**
 251  * \brief       Retrieve a bitstring ASN.1 tag without unused bits and its
 252  *              value.
 253  *              Updates the pointer to the beginning of the bit/octet string.
 254  *
 255  * \param p     The position in the ASN.1 data
 256  * \param end   End of data
 257  * \param len   Length of the actual bit/octect string in bytes
 258  *
 259  * \return      0 if successful or a specific ASN.1 error code.
 260  */
 261 int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end,
 262                              size_t *len );
 263
 264 /**
 265  * \brief       Parses and splits an ASN.1 "SEQUENCE OF <tag>"
 266  *              Updated the pointer to immediately behind the full sequence tag.
 267  *
 268  * \param p     The position in the ASN.1 data
 269  * \param end   End of data
 270  * \param cur   First variable in the chain to fill
 271  * \param tag   Type of sequence
 272  *
 273  * \return      0 if successful or a specific ASN.1 error code.
 274  */
 275 int mbedtls_asn1_get_sequence_of( unsigned char **p,
 276                           const unsigned char *end,
 277                           mbedtls_asn1_sequence *cur,
 278                           int tag);
 279
 280 #if defined(MBEDTLS_BIGNUM_C)
 281 /**
 282  * \brief       Retrieve a MPI value from an integer ASN.1 tag.
 283  *              Updates the pointer to immediately behind the full tag.
 284  *
 285  * \param p     The position in the ASN.1 data
 286  * \param end   End of data
 287  * \param X     The MPI that will receive the value
 288  *
 289  * \return      0 if successful or a specific ASN.1 or MPI error code.
 290  */
 291 int mbedtls_asn1_get_mpi( unsigned char **p,
 292                   const unsigned char *end,
 293                   mbedtls_mpi *X );
 294 #endif /* MBEDTLS_BIGNUM_C */
 295
 296 /**
 297  * \brief       Retrieve an AlgorithmIdentifier ASN.1 sequence.
 298  *              Updates the pointer to immediately behind the full
 299  *              AlgorithmIdentifier.
 300  *
 301  * \param p     The position in the ASN.1 data
 302  * \param end   End of data
 303  * \param alg   The buffer to receive the OID
 304  * \param params The buffer to receive the params (if any)
 305  *
 306  * \return      0 if successful or a specific ASN.1 or MPI error code.
 307  */
 308 int mbedtls_asn1_get_alg( unsigned char **p,
 309                   const unsigned char *end,
 310                   mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params );
 311
 312 /**
 313  * \brief       Retrieve an AlgorithmIdentifier ASN.1 sequence with NULL or no
 314  *              params.
 315  *              Updates the pointer to immediately behind the full
 316  *              AlgorithmIdentifier.
 317  *
 318  * \param p     The position in the ASN.1 data
 319  * \param end   End of data
 320  * \param alg   The buffer to receive the OID
 321  *
 322  * \return      0 if successful or a specific ASN.1 or MPI error code.
 323  */
 324 int mbedtls_asn1_get_alg_null( unsigned char **p,
 325                        const unsigned char *end,
 326                        mbedtls_asn1_buf *alg );
 327
 328 /**
 329  * \brief       Find a specific named_data entry in a sequence or list based on
 330  *              the OID.
 331  *
 332  * \param list  The list to seek through
 333  * \param oid   The OID to look for
 334  * \param len   Size of the OID
 335  *
 336  * \return      NULL if not found, or a pointer to the existing entry.
 337  */
 338 mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list,
 339                                        const char *oid, size_t len );
 340
 341 /**
 342  * \brief       Free a mbedtls_asn1_named_data entry
 343  *
 344  * \param entry The named data entry to free
 345  */
 346 void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *entry );
 347
 348 /**
 349  * \brief       Free all entries in a mbedtls_asn1_named_data list
 350  *              Head will be set to NULL
 351  *
 352  * \param head  Pointer to the head of the list of named data entries to free
 353  */
 354 void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head );
 355
 356 #ifdef __cplusplus
 357 }
 358 #endif
 359
 360 #endif /* asn1.h */