| 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 */ |