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