4 * \brief Generic ASN.1 parsing
6 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
7 * SPDX-License-Identifier: GPL-2.0
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 * This file is part of mbed TLS (https://tls.mbed.org)
25 #ifndef MBEDTLS_ASN1_H
26 #define MBEDTLS_ASN1_H
28 #if !defined(MBEDTLS_CONFIG_FILE)
31 #include MBEDTLS_CONFIG_FILE
34 #if defined(MBEDTLS_BIGNUM_C)
39 * \addtogroup asn1_module
44 * \name ASN1 Error codes
45 * These error codes are OR'ed to X509 error codes for
46 * higher error granularity.
47 * ASN1 is a standard to specify data structures.
50 #define MBEDTLS_ERR_ASN1_OUT_OF_DATA -0x0060 /**< Out of data when parsing an ASN1 data structure. */
51 #define MBEDTLS_ERR_ASN1_UNEXPECTED_TAG -0x0062 /**< ASN1 tag was of an unexpected value. */
52 #define MBEDTLS_ERR_ASN1_INVALID_LENGTH -0x0064 /**< Error when trying to determine the length or invalid length. */
53 #define MBEDTLS_ERR_ASN1_LENGTH_MISMATCH -0x0066 /**< Actual length differs from expected length. */
54 #define MBEDTLS_ERR_ASN1_INVALID_DATA -0x0068 /**< Data is invalid. (not used) */
55 #define MBEDTLS_ERR_ASN1_ALLOC_FAILED -0x006A /**< Memory allocation failed */
56 #define MBEDTLS_ERR_ASN1_BUF_TOO_SMALL -0x006C /**< Buffer too small when writing ASN.1 data structure. */
62 * These constants comply with DER encoded the ANS1 type tags.
63 * DER encoding uses hexadecimal representation.
64 * An example DER sequence is:\n
65 * - 0x02 -- tag indicating INTEGER
66 * - 0x01 -- length in octets
68 * Such sequences are typically read into \c ::mbedtls_x509_buf.
71 #define MBEDTLS_ASN1_BOOLEAN 0x01
72 #define MBEDTLS_ASN1_INTEGER 0x02
73 #define MBEDTLS_ASN1_BIT_STRING 0x03
74 #define MBEDTLS_ASN1_OCTET_STRING 0x04
75 #define MBEDTLS_ASN1_NULL 0x05
76 #define MBEDTLS_ASN1_OID 0x06
77 #define MBEDTLS_ASN1_UTF8_STRING 0x0C
78 #define MBEDTLS_ASN1_SEQUENCE 0x10
79 #define MBEDTLS_ASN1_SET 0x11
80 #define MBEDTLS_ASN1_PRINTABLE_STRING 0x13
81 #define MBEDTLS_ASN1_T61_STRING 0x14
82 #define MBEDTLS_ASN1_IA5_STRING 0x16
83 #define MBEDTLS_ASN1_UTC_TIME 0x17
84 #define MBEDTLS_ASN1_GENERALIZED_TIME 0x18
85 #define MBEDTLS_ASN1_UNIVERSAL_STRING 0x1C
86 #define MBEDTLS_ASN1_BMP_STRING 0x1E
87 #define MBEDTLS_ASN1_PRIMITIVE 0x00
88 #define MBEDTLS_ASN1_CONSTRUCTED 0x20
89 #define MBEDTLS_ASN1_CONTEXT_SPECIFIC 0x80
91 /* \} addtogroup asn1_module */
93 /** Returns the size of the binary string, without the trailing \\0 */
94 #define MBEDTLS_OID_SIZE(x) (sizeof(x) - 1)
97 * Compares an mbedtls_asn1_buf structure to a reference OID.
99 * Only works for 'defined' oid_str values (MBEDTLS_OID_HMAC_SHA1), you cannot use a
100 * 'unsigned char *oid' here!
102 #define MBEDTLS_OID_CMP(oid_str, oid_buf) \
103 ( ( MBEDTLS_OID_SIZE(oid_str) != (oid_buf)->len ) || \
104 memcmp( (oid_str), (oid_buf)->p, (oid_buf)->len) != 0 )
111 * \name Functions to parse ASN.1 data structures
116 * Type-length-value structure that allows for ASN1 using DER.
118 typedef struct mbedtls_asn1_buf
120 int tag
; /**< ASN1 type, e.g. MBEDTLS_ASN1_UTF8_STRING. */
121 size_t len
; /**< ASN1 length, in octets. */
122 unsigned char *p
; /**< ASN1 data, e.g. in ASCII. */
127 * Container for ASN1 bit strings.
129 typedef struct mbedtls_asn1_bitstring
131 size_t len
; /**< ASN1 length, in octets. */
132 unsigned char unused_bits
; /**< Number of unused bits at the end of the string */
133 unsigned char *p
; /**< Raw ASN1 data for the bit string */
135 mbedtls_asn1_bitstring
;
138 * Container for a sequence of ASN.1 items
140 typedef struct mbedtls_asn1_sequence
142 mbedtls_asn1_buf buf
; /**< Buffer containing the given ASN.1 item. */
143 struct mbedtls_asn1_sequence
*next
; /**< The next entry in the sequence. */
145 mbedtls_asn1_sequence
;
148 * Container for a sequence or list of 'named' ASN.1 data items
150 typedef struct mbedtls_asn1_named_data
152 mbedtls_asn1_buf oid
; /**< The object identifier. */
153 mbedtls_asn1_buf val
; /**< The named value. */
154 struct mbedtls_asn1_named_data
*next
; /**< The next entry in the sequence. */
155 unsigned char next_merged
; /**< Merge next item into the current one? */
157 mbedtls_asn1_named_data
;
160 * \brief Get the length of an ASN.1 element.
161 * Updates the pointer to immediately behind the length.
163 * \param p The position in the ASN.1 data
164 * \param end End of data
165 * \param len The variable that will receive the value
167 * \return 0 if successful, MBEDTLS_ERR_ASN1_OUT_OF_DATA on reaching
168 * end of data, MBEDTLS_ERR_ASN1_INVALID_LENGTH if length is
171 int mbedtls_asn1_get_len( unsigned char **p
,
172 const unsigned char *end
,
176 * \brief Get the tag and length of the tag. Check for the requested tag.
177 * Updates the pointer to immediately behind the tag and length.
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 length
182 * \param tag The expected tag
184 * \return 0 if successful, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if tag did
185 * not match requested tag, or another specific ASN.1 error code.
187 int mbedtls_asn1_get_tag( unsigned char **p
,
188 const unsigned char *end
,
189 size_t *len
, int tag
);
192 * \brief Retrieve a boolean ASN.1 tag and its value.
193 * Updates the pointer to immediately behind the full tag.
195 * \param p The position in the ASN.1 data
196 * \param end End of data
197 * \param val The variable that will receive the value
199 * \return 0 if successful or a specific ASN.1 error code.
201 int mbedtls_asn1_get_bool( unsigned char **p
,
202 const unsigned char *end
,
206 * \brief Retrieve an integer ASN.1 tag and its value.
207 * Updates the pointer to immediately behind the full tag.
209 * \param p The position in the ASN.1 data
210 * \param end End of data
211 * \param val The variable that will receive the value
213 * \return 0 if successful or a specific ASN.1 error code.
215 int mbedtls_asn1_get_int( unsigned char **p
,
216 const unsigned char *end
,
220 * \brief Retrieve a bitstring ASN.1 tag and its value.
221 * Updates the pointer to immediately behind the full tag.
223 * \param p The position in the ASN.1 data
224 * \param end End of data
225 * \param bs The variable that will receive the value
227 * \return 0 if successful or a specific ASN.1 error code.
229 int mbedtls_asn1_get_bitstring( unsigned char **p
, const unsigned char *end
,
230 mbedtls_asn1_bitstring
*bs
);
233 * \brief Retrieve a bitstring ASN.1 tag without unused bits and its
235 * Updates the pointer to the beginning of the bit/octet string.
237 * \param p The position in the ASN.1 data
238 * \param end End of data
239 * \param len Length of the actual bit/octect string in bytes
241 * \return 0 if successful or a specific ASN.1 error code.
243 int mbedtls_asn1_get_bitstring_null( unsigned char **p
, const unsigned char *end
,
247 * \brief Parses and splits an ASN.1 "SEQUENCE OF <tag>"
248 * Updated the pointer to immediately behind the full sequence tag.
250 * \param p The position in the ASN.1 data
251 * \param end End of data
252 * \param cur First variable in the chain to fill
253 * \param tag Type of sequence
255 * \return 0 if successful or a specific ASN.1 error code.
257 int mbedtls_asn1_get_sequence_of( unsigned char **p
,
258 const unsigned char *end
,
259 mbedtls_asn1_sequence
*cur
,
262 #if defined(MBEDTLS_BIGNUM_C)
264 * \brief Retrieve a MPI value from an integer ASN.1 tag.
265 * Updates the pointer to immediately behind the full tag.
267 * \param p The position in the ASN.1 data
268 * \param end End of data
269 * \param X The MPI that will receive the value
271 * \return 0 if successful or a specific ASN.1 or MPI error code.
273 int mbedtls_asn1_get_mpi( unsigned char **p
,
274 const unsigned char *end
,
276 #endif /* MBEDTLS_BIGNUM_C */
279 * \brief Retrieve an AlgorithmIdentifier ASN.1 sequence.
280 * Updates the pointer to immediately behind the full
281 * AlgorithmIdentifier.
283 * \param p The position in the ASN.1 data
284 * \param end End of data
285 * \param alg The buffer to receive the OID
286 * \param params The buffer to receive the params (if any)
288 * \return 0 if successful or a specific ASN.1 or MPI error code.
290 int mbedtls_asn1_get_alg( unsigned char **p
,
291 const unsigned char *end
,
292 mbedtls_asn1_buf
*alg
, mbedtls_asn1_buf
*params
);
295 * \brief Retrieve an AlgorithmIdentifier ASN.1 sequence with NULL or no
297 * Updates the pointer to immediately behind the full
298 * AlgorithmIdentifier.
300 * \param p The position in the ASN.1 data
301 * \param end End of data
302 * \param alg The buffer to receive the OID
304 * \return 0 if successful or a specific ASN.1 or MPI error code.
306 int mbedtls_asn1_get_alg_null( unsigned char **p
,
307 const unsigned char *end
,
308 mbedtls_asn1_buf
*alg
);
311 * \brief Find a specific named_data entry in a sequence or list based on
314 * \param list The list to seek through
315 * \param oid The OID to look for
316 * \param len Size of the OID
318 * \return NULL if not found, or a pointer to the existing entry.
320 mbedtls_asn1_named_data
*mbedtls_asn1_find_named_data( mbedtls_asn1_named_data
*list
,
321 const char *oid
, size_t len
);
324 * \brief Free a mbedtls_asn1_named_data entry
326 * \param entry The named data entry to free
328 void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data
*entry
);
331 * \brief Free all entries in a mbedtls_asn1_named_data list
332 * Head will be set to NULL
334 * \param head Pointer to the head of the list of named data entries to free
336 void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data
**head
);