/**
* \file asn1.h
*
* \brief Generic ASN.1 parsing
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBEDTLS_ASN1_H
#define MBEDTLS_ASN1_H
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#include <stddef.h>
#if defined(MBEDTLS_BIGNUM_C)
#include "mbedtls/bignum.h"
#endif
/**
* \addtogroup mbedtls
* \{
* \defgroup mbedtls_asn1_module ASN.1
* \{
*/
/**
* \name ASN1 Error codes
* These error codes are OR'ed to X509 error codes for
* higher error granularity.
* ASN1 is a standard to specify data structures.
* \{
*/
#define MBEDTLS_ERR_ASN1_OUT_OF_DATA -0x0060 /**< Out of data when parsing an ASN1 data structure. */
#define MBEDTLS_ERR_ASN1_UNEXPECTED_TAG -0x0062 /**< ASN1 tag was of an unexpected value. */
#define MBEDTLS_ERR_ASN1_INVALID_LENGTH -0x0064 /**< Error when trying to determine the length or invalid length. */
#define MBEDTLS_ERR_ASN1_LENGTH_MISMATCH -0x0066 /**< Actual length differs from expected length. */
#define MBEDTLS_ERR_ASN1_INVALID_DATA -0x0068 /**< Data is invalid. */
#define MBEDTLS_ERR_ASN1_ALLOC_FAILED -0x006A /**< Memory allocation failed */
#define MBEDTLS_ERR_ASN1_BUF_TOO_SMALL -0x006C /**< Buffer too small when writing ASN.1 data structure. */
/** \} name */
/**
* \name DER constants
* These constants comply with the DER encoded ASN.1 type tags.
* DER encoding uses hexadecimal representation.
* An example DER sequence is:\n
* - 0x02 -- tag indicating INTEGER
* - 0x01 -- length in octets
* - 0x05 -- value
* Such sequences are typically read into \c ::mbedtls_x509_buf.
* \{
*/
#define MBEDTLS_ASN1_BOOLEAN 0x01 ///< Boolean
#define MBEDTLS_ASN1_INTEGER 0x02 ///< Integer
#define MBEDTLS_ASN1_BIT_STRING 0x03 ///< Bit String
#define MBEDTLS_ASN1_OCTET_STRING 0x04 ///< Octet String
#define MBEDTLS_ASN1_NULL 0x05 ///< Null
#define MBEDTLS_ASN1_OID 0x06 ///< OID
#define MBEDTLS_ASN1_ENUMERATED 0x0A ///< Enumerated
#define MBEDTLS_ASN1_UTF8_STRING 0x0C ///< UTF-8 String
#define MBEDTLS_ASN1_SEQUENCE 0x10 ///< Sequence
#define MBEDTLS_ASN1_SET 0x11 ///< Set
#define MBEDTLS_ASN1_PRINTABLE_STRING 0x13 ///< Printable String
#define MBEDTLS_ASN1_T61_STRING 0x14 ///< T61 String
#define MBEDTLS_ASN1_IA5_STRING 0x16 ///< IA5 String
#define MBEDTLS_ASN1_UTC_TIME 0x17 ///< UTC Time
#define MBEDTLS_ASN1_GENERALIZED_TIME 0x18 ///< Generalized Time
#define MBEDTLS_ASN1_UNIVERSAL_STRING 0x1C ///< Universal String
#define MBEDTLS_ASN1_BMP_STRING 0x1E ///< BMP String
#define MBEDTLS_ASN1_PRIMITIVE 0x00 ///< Primitive
#define MBEDTLS_ASN1_CONSTRUCTED 0x20 ///< Constructed
#define MBEDTLS_ASN1_CONTEXT_SPECIFIC 0x80 ///< Context Specific
/* Slightly smaller way to check if tag is a string tag
* compared to canonical implementation. */
#define MBEDTLS_ASN1_IS_STRING_TAG( tag ) \
( ( tag ) < 32u && ( \
( ( 1u << ( tag ) ) & ( ( 1u << MBEDTLS_ASN1_BMP_STRING ) | \
( 1u << MBEDTLS_ASN1_UTF8_STRING ) | \
( 1u << MBEDTLS_ASN1_T61_STRING ) | \
( 1u << MBEDTLS_ASN1_IA5_STRING ) | \
( 1u << MBEDTLS_ASN1_UNIVERSAL_STRING ) | \
( 1u << MBEDTLS_ASN1_PRINTABLE_STRING ) | \
( 1u << MBEDTLS_ASN1_BIT_STRING ) ) ) != 0 ) )
/*
* Bit masks for each of the components of an ASN.1 tag as specified in
* ITU X.690 (08/2015), section 8.1 "General rules for encoding",
* paragraph 8.1.2.2:
*
* Bit 8 7 6 5 1
* +-------+-----+------------+
* | Class | P/C | Tag number |
* +-------+-----+------------+
*/
#define MBEDTLS_ASN1_TAG_CLASS_MASK 0xC0
#define MBEDTLS_ASN1_TAG_PC_MASK 0x20
#define MBEDTLS_ASN1_TAG_VALUE_MASK 0x1F
/** \} name */
/** Returns the size of the binary string, without the trailing \\0 */
#define MBEDTLS_OID_SIZE(x) (sizeof(x) - 1)
/**
* Compares an mbedtls_asn1_buf structure to a reference OID.
*
* Only works for 'defined' oid_str values (MBEDTLS_OID_HMAC_SHA1), you cannot use a
* 'unsigned char *oid' here!
*/
#define MBEDTLS_OID_CMP(oid_str, oid_buf) \
( ( MBEDTLS_OID_SIZE(oid_str) != (oid_buf)->len ) || \
memcmp( (oid_str), (oid_buf)->p, (oid_buf)->len) != 0 )
#define MBEDTLS_OID_CMP_RAW(oid_str, oid_buf, oid_buf_len) \
( ( MBEDTLS_OID_SIZE(oid_str) != (oid_buf_len) ) || \
memcmp( (oid_str), (oid_buf), (oid_buf_len) ) != 0 )
#ifdef __cplusplus
extern "C" {
#endif
/**
* Type-length-value structure that allows for ASN1 using DER.
*/
typedef struct mbedtls_asn1_buf
{
int tag; /**< ASN1 type, e.g. MBEDTLS_ASN1_UTF8_STRING. */
size_t len; /**< ASN1 length, in octets. */
unsigned char *p; /**< ASN1 data, e.g. in ASCII. */
}
mbedtls_asn1_buf;
/**
* Container for ASN1 bit strings.
*/
typedef struct mbedtls_asn1_bitstring
{
size_t len; /**< ASN1 length, in octets. */
unsigned char unused_bits; /**< Number of unused bits at the end of the string */
unsigned char *p; /**< Raw ASN1 data for the bit string */
}
mbedtls_asn1_bitstring;
/**
* Container for a sequence of ASN.1 items
*/
typedef struct mbedtls_asn1_sequence
{
mbedtls_asn1_buf buf; /**< Buffer containing the given ASN.1 item. */
struct mbedtls_asn1_sequence *next; /**< The next entry in the sequence. */
}
mbedtls_asn1_sequence;
/**
* Container for a sequence or list of 'named' ASN.1 data items
*/
typedef struct mbedtls_asn1_named_data
{
mbedtls_asn1_buf oid; /**< The object identifier. */
mbedtls_asn1_buf val; /**< The named value. */
struct mbedtls_asn1_named_data *next; /**< The next entry in the sequence. */
unsigned char next_merged; /**< Merge next item into the current one? */
}
mbedtls_asn1_named_data;
/**
* \brief Get the length of an ASN.1 element.
* Updates the pointer to immediately behind the length.
*
* \param p On entry, \c *p points to the first byte of the length,
* i.e. immediately after the tag.
* On successful completion, \c *p points to the first byte
* after the length, i.e. the first byte of the content.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param len On successful completion, \c *len contains the length
* read from the ASN.1 input.
*
* \return 0 if successful.
* \return #MBEDTLS_ERR_ASN1_OUT_OF_DATA if the ASN.1 element
* would end beyond \p end.
* \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the length is unparseable.
*/
int mbedtls_asn1_get_len( unsigned char **p,
const unsigned char *end,
size_t *len );
/**
* \brief Get the tag and length of the element.
* Check for the requested tag.
* Updates the pointer to immediately behind the tag and length.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* after the length, i.e. the first byte of the content.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param len On successful completion, \c *len contains the length
* read from the ASN.1 input.
* \param tag The expected tag.
*
* \return 0 if successful.
* \return #MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if the data does not start
* with the requested tag.
* \return #MBEDTLS_ERR_ASN1_OUT_OF_DATA if the ASN.1 element
* would end beyond \p end.
* \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the length is unparseable.
*/
int mbedtls_asn1_get_tag( unsigned char **p,
const unsigned char *end,
size_t *len, int tag );
/**
* \brief Retrieve a boolean ASN.1 tag and its value.
* Updates the pointer to immediately behind the full tag.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* beyond the ASN.1 element.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param val On success, the parsed value (\c 0 or \c 1).
*
* \return 0 if successful.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 BOOLEAN.
*/
int mbedtls_asn1_get_bool( unsigned char **p,
const unsigned char *end,
int *val );
/**
* \brief Retrieve an integer ASN.1 tag and its value.
* Updates the pointer to immediately behind the full tag.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* beyond the ASN.1 element.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param val On success, the parsed value.
*
* \return 0 if successful.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 INTEGER.
* \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the parsed value does
* not fit in an \c int.
*/
int mbedtls_asn1_get_int( unsigned char **p,
const unsigned char *end,
int *val );
/**
* \brief Retrieve an enumerated ASN.1 tag and its value.
* Updates the pointer to immediately behind the full tag.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* beyond the ASN.1 element.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param val On success, the parsed value.
*
* \return 0 if successful.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 ENUMERATED.
* \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the parsed value does
* not fit in an \c int.
*/
int mbedtls_asn1_get_enum( unsigned char **p,
const unsigned char *end,
int *val );
/**
* \brief Retrieve a bitstring ASN.1 tag and its value.
* Updates the pointer to immediately behind the full tag.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p is equal to \p end.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param bs On success, ::mbedtls_asn1_bitstring information about
* the parsed value.
*
* \return 0 if successful.
* \return #MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input contains
* extra data after a valid BIT STRING.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 BIT STRING.
*/
int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end,
mbedtls_asn1_bitstring *bs );
/**
* \brief Retrieve a bitstring ASN.1 tag without unused bits and its
* value.
* Updates the pointer to the beginning of the bit/octet string.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* of the content of the BIT STRING.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param len On success, \c *len is the length of the content in bytes.
*
* \return 0 if successful.
* \return #MBEDTLS_ERR_ASN1_INVALID_DATA if the input starts with
* a valid BIT STRING with a nonzero number of unused bits.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 BIT STRING.
*/
int mbedtls_asn1_get_bitstring_null( unsigned char **p,
const unsigned char *end,
size_t *len );
/**
* \brief Parses and splits an ASN.1 "SEQUENCE OF <tag>".
* Updates the pointer to immediately behind the full sequence tag.
*
* This function allocates memory for the sequence elements. You can free
* the allocated memory with mbedtls_asn1_sequence_free().
*
* \note On error, this function may return a partial list in \p cur.
* You must set `cur->next = NULL` before calling this function!
* Otherwise it is impossible to distinguish a previously non-null
* pointer from a pointer to an object allocated by this function.
*
* \note If the sequence is empty, this function does not modify
* \c *cur. If the sequence is valid and non-empty, this
* function sets `cur->buf.tag` to \p tag. This allows
* callers to distinguish between an empty sequence and
* a one-element sequence.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p is equal to \p end.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param cur A ::mbedtls_asn1_sequence which this function fills.
* When this function returns, \c *cur is the head of a linked
* list. Each node in this list is allocated with
* mbedtls_calloc() apart from \p cur itself, and should
* therefore be freed with mbedtls_free().
* The list describes the content of the sequence.
* The head of the list (i.e. \c *cur itself) describes the
* first element, `*cur->next` describes the second element, etc.
* For each element, `buf.tag == tag`, `buf.len` is the length
* of the content of the content of the element, and `buf.p`
* points to the first byte of the content (i.e. immediately
* past the length of the element).
* Note that list elements may be allocated even on error.
* \param tag Each element of the sequence must have this tag.
*
* \return 0 if successful.
* \return #MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input contains
* extra data after a valid SEQUENCE OF \p tag.
* \return #MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if the input starts with
* an ASN.1 SEQUENCE in which an element has a tag that
* is different from \p tag.
* \return #MBEDTLS_ERR_ASN1_ALLOC_FAILED if a memory allocation failed.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 SEQUENCE.
*/
int mbedtls_asn1_get_sequence_of( unsigned char **p,
const unsigned char *end,
mbedtls_asn1_sequence *cur,
int tag );
/**
* \brief Free a heap-allocated linked list presentation of
* an ASN.1 sequence, including the first element.
*
* There are two common ways to manage the memory used for the representation
* of a parsed ASN.1 sequence:
* - Allocate a head node `mbedtls_asn1_sequence *head` with mbedtls_calloc().
* Pass this node as the `cur` argument to mbedtls_asn1_get_sequence_of().
* When you have finished processing the sequence,
* call mbedtls_asn1_sequence_free() on `head`.
* - Allocate a head node `mbedtls_asn1_sequence *head` in any manner,
* for example on the stack. Make sure that `head->next == NULL`.
* Pass `head` as the `cur` argument to mbedtls_asn1_get_sequence_of().
* When you have finished processing the sequence,
* call mbedtls_asn1_sequence_free() on `head->cur`,
* then free `head` itself in the appropriate manner.
*
* \param seq The address of the first sequence component. This may
* be \c NULL, in which case this functions returns
* immediately.
*/
void mbedtls_asn1_sequence_free( mbedtls_asn1_sequence *seq );
/**
* \brief Traverse an ASN.1 SEQUENCE container and
* call a callback for each entry.
*
* This function checks that the input is a SEQUENCE of elements that
* each have a "must" tag, and calls a callback function on the elements
* that have a "may" tag.
*
* For example, to validate that the input is a SEQUENCE of `tag1` and call
* `cb` on each element, use
* ```
* mbedtls_asn1_traverse_sequence_of(&p, end, 0xff, tag1, 0, 0, cb, ctx);
* ```
*
* To validate that the input is a SEQUENCE of ANY and call `cb` on
* each element, use
* ```
* mbedtls_asn1_traverse_sequence_of(&p, end, 0, 0, 0, 0, cb, ctx);
* ```
*
* To validate that the input is a SEQUENCE of CHOICE {NULL, OCTET STRING}
* and call `cb` on each element that is an OCTET STRING, use
* ```
* mbedtls_asn1_traverse_sequence_of(&p, end, 0xfe, 0x04, 0xff, 0x04, cb, ctx);
* ```
*
* The callback is called on the elements with a "may" tag from left to
* right. If the input is not a valid SEQUENCE of elements with a "must" tag,
* the callback is called on the elements up to the leftmost point where
* the input is invalid.
*
* \warning This function is still experimental and may change
* at any time.
*
* \param p The address of the pointer to the beginning of
* the ASN.1 SEQUENCE header. This is updated to
* point to the end of the ASN.1 SEQUENCE container
* on a successful invocation.
* \param end The end of the ASN.1 SEQUENCE container.
* \param tag_must_mask A mask to be applied to the ASN.1 tags found within
* the SEQUENCE before comparing to \p tag_must_value.
* \param tag_must_val The required value of each ASN.1 tag found in the
* SEQUENCE, after masking with \p tag_must_mask.
* Mismatching tags lead to an error.
* For example, a value of \c 0 for both \p tag_must_mask
* and \p tag_must_val means that every tag is allowed,
* while a value of \c 0xFF for \p tag_must_mask means
* that \p tag_must_val is the only allowed tag.
* \param tag_may_mask A mask to be applied to the ASN.1 tags found within
* the SEQUENCE before comparing to \p tag_may_value.
* \param tag_may_val The desired value of each ASN.1 tag found in the
* SEQUENCE, after masking with \p tag_may_mask.
* Mismatching tags will be silently ignored.
* For example, a value of \c 0 for \p tag_may_mask and
* \p tag_may_val means that any tag will be considered,
* while a value of \c 0xFF for \p tag_may_mask means
* that all tags with value different from \p tag_may_val
* will be ignored.
* \param cb The callback to trigger for each component
* in the ASN.1 SEQUENCE that matches \p tag_may_val.
* The callback function is called with the following
* parameters:
* - \p ctx.
* - The tag of the current element.
* - A pointer to the start of the current element's
* content inside the input.
* - The length of the content of the current element.
* If the callback returns a non-zero value,
* the function stops immediately,
* forwarding the callback's return value.
* \param ctx The context to be passed to the callback \p cb.
*
* \return \c 0 if successful the entire ASN.1 SEQUENCE
* was traversed without parsing or callback errors.
* \return #MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input
* contains extra data after a valid SEQUENCE
* of elements with an accepted tag.
* \return #MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if the input starts
* with an ASN.1 SEQUENCE in which an element has a tag
* that is not accepted.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 SEQUENCE.
* \return A non-zero error code forwarded from the callback
* \p cb in case the latter returns a non-zero value.
*/
int mbedtls_asn1_traverse_sequence_of(
unsigned char **p,
const unsigned char *end,
unsigned char tag_must_mask, unsigned char tag_must_val,
unsigned char tag_may_mask, unsigned char tag_may_val,
int (*cb)( void *ctx, int tag,
unsigned char* start, size_t len ),
void *ctx );
#if defined(MBEDTLS_BIGNUM_C)
/**
* \brief Retrieve an integer ASN.1 tag and its value.
* Updates the pointer to immediately behind the full tag.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* beyond the ASN.1 element.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param X On success, the parsed value.
*
* \return 0 if successful.
* \return An ASN.1 error code if the input does not start with
* a valid ASN.1 INTEGER.
* \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the parsed value does
* not fit in an \c int.
* \return An MPI error code if the parsed value is too large.
*/
int mbedtls_asn1_get_mpi( unsigned char **p,
const unsigned char *end,
mbedtls_mpi *X );
#endif /* MBEDTLS_BIGNUM_C */
/**
* \brief Retrieve an AlgorithmIdentifier ASN.1 sequence.
* Updates the pointer to immediately behind the full
* AlgorithmIdentifier.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* beyond the AlgorithmIdentifier element.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param alg The buffer to receive the OID.
* \param params The buffer to receive the parameters.
* This is zeroized if there are no parameters.
*
* \return 0 if successful or a specific ASN.1 or MPI error code.
*/
int mbedtls_asn1_get_alg( unsigned char **p,
const unsigned char *end,
mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params );
/**
* \brief Retrieve an AlgorithmIdentifier ASN.1 sequence with NULL or no
* params.
* Updates the pointer to immediately behind the full
* AlgorithmIdentifier.
*
* \param p On entry, \c *p points to the start of the ASN.1 element.
* On successful completion, \c *p points to the first byte
* beyond the AlgorithmIdentifier element.
* On error, the value of \c *p is undefined.
* \param end End of data.
* \param alg The buffer to receive the OID.
*
* \return 0 if successful or a specific ASN.1 or MPI error code.
*/
int mbedtls_asn1_get_alg_null( unsigned char **p,
const unsigned char *end,
mbedtls_asn1_buf *alg );
/**
* \brief Find a specific named_data entry in a sequence or list based on
* the OID.
*
* \param list The list to seek through
* \param oid The OID to look for
* \param len Size of the OID
*
* \return NULL if not found, or a pointer to the existing entry.
*/
mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list,
const char *oid, size_t len );
/**
* \brief Free a mbedtls_asn1_named_data entry
*
* \param entry The named data entry to free.
* This function calls mbedtls_free() on
* `entry->oid.p` and `entry->val.p`.
*/
void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *entry );
/**
* \brief Free all entries in a mbedtls_asn1_named_data list.
*
* \param head Pointer to the head of the list of named data entries to free.
* This function calls mbedtls_asn1_free_named_data() and
* mbedtls_free() on each list element and
* sets \c *head to \c NULL.
*/
void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head );
#ifdef __cplusplus
}
#endif
/// \}
/// \}
#endif /* asn1.h */
