/** * \file asn1.h * * \brief Generic ASN.1 parsing * * Copyright (C) 2006-2013, ARM Limited, All Rights Reserved * * This file is part of mbed TLS (https://polarssl.org) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #ifndef POLARSSL_ASN1_H #define POLARSSL_ASN1_H #if !defined(POLARSSL_CONFIG_FILE) #include "config.h" #else #include POLARSSL_CONFIG_FILE #endif #if defined(POLARSSL_BIGNUM_C) #include "bignum.h" #endif #include /** * \addtogroup asn1_module * \{ */ /** * \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 POLARSSL_ERR_ASN1_OUT_OF_DATA -0x0060 /**< Out of data when parsing an ASN1 data structure. */ #define POLARSSL_ERR_ASN1_UNEXPECTED_TAG -0x0062 /**< ASN1 tag was of an unexpected value. */ #define POLARSSL_ERR_ASN1_INVALID_LENGTH -0x0064 /**< Error when trying to determine the length or invalid length. */ #define POLARSSL_ERR_ASN1_LENGTH_MISMATCH -0x0066 /**< Actual length differs from expected length. */ #define POLARSSL_ERR_ASN1_INVALID_DATA -0x0068 /**< Data is invalid. (not used) */ #define POLARSSL_ERR_ASN1_MALLOC_FAILED -0x006A /**< Memory allocation failed */ #define POLARSSL_ERR_ASN1_BUF_TOO_SMALL -0x006C /**< Buffer too small when writing ASN.1 data structure. */ /* \} name */ /** * \name DER constants * These constants comply with DER encoded the ANS1 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 ::x509_buf. * \{ */ #define ASN1_BOOLEAN 0x01 #define ASN1_INTEGER 0x02 #define ASN1_BIT_STRING 0x03 #define ASN1_OCTET_STRING 0x04 #define ASN1_NULL 0x05 #define ASN1_OID 0x06 #define ASN1_UTF8_STRING 0x0C #define ASN1_SEQUENCE 0x10 #define ASN1_SET 0x11 #define ASN1_PRINTABLE_STRING 0x13 #define ASN1_T61_STRING 0x14 #define ASN1_IA5_STRING 0x16 #define ASN1_UTC_TIME 0x17 #define ASN1_GENERALIZED_TIME 0x18 #define ASN1_UNIVERSAL_STRING 0x1C #define ASN1_BMP_STRING 0x1E #define ASN1_PRIMITIVE 0x00 #define ASN1_CONSTRUCTED 0x20 #define ASN1_CONTEXT_SPECIFIC 0x80 /* \} name */ /* \} addtogroup asn1_module */ /** Returns the size of the binary string, without the trailing \\0 */ #define OID_SIZE(x) (sizeof(x) - 1) /** * Compares an asn1_buf structure to a reference OID. * * Only works for 'defined' oid_str values (OID_HMAC_SHA1), you cannot use a * 'unsigned char *oid' here! * * Warning: returns true when the OIDs are equal (unlike memcmp)! */ #define OID_CMP(oid_str, oid_buf) \ ( ( OID_SIZE(oid_str) == (oid_buf)->len ) && \ memcmp( (oid_str), (oid_buf)->p, (oid_buf)->len) == 0 ) #ifdef __cplusplus extern "C" { #endif /** * \name Functions to parse ASN.1 data structures * \{ */ /** * Type-length-value structure that allows for ASN1 using DER. */ typedef struct _asn1_buf { int tag; /**< ASN1 type, e.g. ASN1_UTF8_STRING. */ size_t len; /**< ASN1 length, e.g. in octets. */ unsigned char *p; /**< ASN1 data, e.g. in ASCII. */ } asn1_buf; /** * Container for ASN1 bit strings. */ typedef struct _asn1_bitstring { size_t len; /**< ASN1 length, e.g. 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 */ } asn1_bitstring; /** * Container for a sequence of ASN.1 items */ typedef struct _asn1_sequence { asn1_buf buf; /**< Buffer containing the given ASN.1 item. */ struct _asn1_sequence *next; /**< The next entry in the sequence. */ } asn1_sequence; /** * Container for a sequence or list of 'named' ASN.1 data items */ typedef struct _asn1_named_data { asn1_buf oid; /**< The object identifier. */ asn1_buf val; /**< The named value. */ struct _asn1_named_data *next; /**< The next entry in the sequence. */ unsigned char next_merged; /**< Merge next item into the current one? */ } asn1_named_data; /** * \brief Get the length of an ASN.1 element. * Updates the pointer to immediately behind the length. * * \param p The position in the ASN.1 data * \param end End of data * \param len The variable that will receive the value * * \return 0 if successful, POLARSSL_ERR_ASN1_OUT_OF_DATA on reaching * end of data, POLARSSL_ERR_ASN1_INVALID_LENGTH if length is * unparseable. */ int asn1_get_len( unsigned char **p, const unsigned char *end, size_t *len ); /** * \brief Get the tag and length of the tag. Check for the requested tag. * Updates the pointer to immediately behind the tag and length. * * \param p The position in the ASN.1 data * \param end End of data * \param len The variable that will receive the length * \param tag The expected tag * * \return 0 if successful, POLARSSL_ERR_ASN1_UNEXPECTED_TAG if tag did * not match requested tag, or another specific ASN.1 error code. */ int 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 The position in the ASN.1 data * \param end End of data * \param val The variable that will receive the value * * \return 0 if successful or a specific ASN.1 error code. */ int 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 The position in the ASN.1 data * \param end End of data * \param val The variable that will receive the value * * \return 0 if successful or a specific ASN.1 error code. */ int asn1_get_int( 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 The position in the ASN.1 data * \param end End of data * \param bs The variable that will receive the value * * \return 0 if successful or a specific ASN.1 error code. */ int asn1_get_bitstring( unsigned char **p, const unsigned char *end, 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 The position in the ASN.1 data * \param end End of data * \param len Length of the actual bit/octect string in bytes * * \return 0 if successful or a specific ASN.1 error code. */ int asn1_get_bitstring_null( unsigned char **p, const unsigned char *end, size_t *len ); /** * \brief Parses and splits an ASN.1 "SEQUENCE OF " * Updated the pointer to immediately behind the full sequence tag. * * \param p The position in the ASN.1 data * \param end End of data * \param cur First variable in the chain to fill * \param tag Type of sequence * * \return 0 if successful or a specific ASN.1 error code. */ int asn1_get_sequence_of( unsigned char **p, const unsigned char *end, asn1_sequence *cur, int tag); #if defined(POLARSSL_BIGNUM_C) /** * \brief Retrieve a MPI value from an integer ASN.1 tag. * Updates the pointer to immediately behind the full tag. * * \param p The position in the ASN.1 data * \param end End of data * \param X The MPI that will receive the value * * \return 0 if successful or a specific ASN.1 or MPI error code. */ int asn1_get_mpi( unsigned char **p, const unsigned char *end, mpi *X ); #endif /* POLARSSL_BIGNUM_C */ /** * \brief Retrieve an AlgorithmIdentifier ASN.1 sequence. * Updates the pointer to immediately behind the full * AlgorithmIdentifier. * * \param p The position in the ASN.1 data * \param end End of data * \param alg The buffer to receive the OID * \param params The buffer to receive the params (if any) * * \return 0 if successful or a specific ASN.1 or MPI error code. */ int asn1_get_alg( unsigned char **p, const unsigned char *end, asn1_buf *alg, 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 The position in the ASN.1 data * \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 asn1_get_alg_null( unsigned char **p, const unsigned char *end, 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. */ asn1_named_data *asn1_find_named_data( asn1_named_data *list, const char *oid, size_t len ); /** * \brief Free a asn1_named_data entry * * \param entry The named data entry to free */ void asn1_free_named_data( asn1_named_data *entry ); /** * \brief Free all entries in a asn1_named_data list * Head will be set to NULL * * \param head Pointer to the head of the list of named data entries to free */ void asn1_free_named_data_list( asn1_named_data **head ); #ifdef __cplusplus } #endif #endif /* asn1.h */