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1 /**

2 * \file asn1.h

3 *

4 * \brief Generic ASN.1 parsing

5 */

6 /*

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

29 #if !defined(MBEDTLS_CONFIG_FILE)

30 #include "config.h"

31 #else

32 #include MBEDTLS_CONFIG_FILE

33 #endif

35 #include <stddef.h>

37 #if defined(MBEDTLS_BIGNUM_C)

38 #include "bignum.h"

39 #endif

41 /**

42 * \addtogroup asn1_module

43 * \{

44 */

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. */

61 /* \} name */

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

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 */

 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 */

 int mbedtls_asn1_get_tag( unsigned char **p,

206 const unsigned char *end,

                   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 */

 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 */

 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 */

 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 */

 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 */

 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 */

 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 */

 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 */

 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 */

 mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list,

                                        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 */

 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 */

 void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head );

355

356 #ifdef __cplusplus

357 }

358 #endif

359

360 #endif /* asn1.h */