gnupg/common/tlv.h

/* tlv.h - Tag-Length-Value Utilities
 *	Copyright (C) 2004 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * This file is free software; you can redistribute it and/or modify
 * it under the terms of either
 *
 *   - the GNU Lesser General Public License as published by the Free
 *     Software Foundation; either version 3 of the License, or (at
 *     your option) any later version.
 *
 * or
 *
 *   - 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.
 *
 * or both in parallel, as here.
 *
 * This file 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, see <https://www.gnu.org/licenses/>.
 */

#ifndef SCD_TLV_H
#define SCD_TLV_H 1

#include "membuf.h"

enum tlv_tag_class {
  CLASS_UNIVERSAL = 0,
  CLASS_APPLICATION = 1,
  CLASS_CONTEXT = 2,
  CLASS_PRIVATE =3
};

enum tlv_tag_type {
  TAG_NONE = 0,
  TAG_BOOLEAN = 1,
  TAG_INTEGER = 2,
  TAG_BIT_STRING = 3,
  TAG_OCTET_STRING = 4,
  TAG_NULL = 5,
  TAG_OBJECT_ID = 6,
  TAG_OBJECT_DESCRIPTOR = 7,
  TAG_EXTERNAL = 8,
  TAG_REAL = 9,
  TAG_ENUMERATED = 10,
  TAG_EMBEDDED_PDV = 11,
  TAG_UTF8_STRING = 12,
  TAG_REALTIVE_OID = 13,
  TAG_SEQUENCE = 16,
  TAG_SET = 17,
  TAG_NUMERIC_STRING = 18,
  TAG_PRINTABLE_STRING = 19,
  TAG_TELETEX_STRING = 20,
  TAG_VIDEOTEX_STRING = 21,
  TAG_IA5_STRING = 22,
  TAG_UTC_TIME = 23,
  TAG_GENERALIZED_TIME = 24,
  TAG_GRAPHIC_STRING = 25,
  TAG_VISIBLE_STRING = 26,
  TAG_GENERAL_STRING = 27,
  TAG_UNIVERSAL_STRING = 28,
  TAG_CHARACTER_STRING = 29,
  TAG_BMP_STRING = 30
};

struct tag_info
{
  int class;
  int is_constructed;
  unsigned long tag;
  size_t length;         /* length part of the TLV */
  size_t nhdr;
  int ndef;              /* It is an indefinite length */
};

struct tlv_builder_s;
typedef struct tlv_builder_s *tlv_builder_t;

struct tlv_parser_s;
typedef struct tlv_parser_s *tlv_parser_t;

/*-- tlv.c --*/

/* Locate a TLV encoded data object in BUFFER of LENGTH and return a
   pointer to value as well as its length in NBYTES.  Return NULL if
   it was not found or if the object does not fit into the buffer. */
const unsigned char *find_tlv (const unsigned char *buffer, size_t length,
                               int tag, size_t *nbytes);


/* Locate a TLV encoded data object in BUFFER of LENGTH and return a
   pointer to value as well as its length in NBYTES.  Return NULL if
   it was not found.  Note, that the function does not check whether
   the value fits into the provided buffer.*/
const unsigned char *find_tlv_unchecked (const unsigned char *buffer,
                                         size_t length,
                                         int tag, size_t *nbytes);

/* ASN.1 BER parser: Parse BUFFER of length SIZE and return the tag
   and the length part from the TLV triplet.  Update BUFFER and SIZE
   on success.  See also tlv_parse_tag.  */
gpg_error_t parse_ber_header (unsigned char const **buffer, size_t *size,
                              int *r_class, int *r_tag,
                              int *r_constructed,
                              int *r_ndef, size_t *r_length, size_t *r_nhdr);


/* Return the next token of an canonical encoded S-expression.  BUF
   is the pointer to the S-expression and BUFLEN is a pointer to the
   length of this S-expression (used to validate the syntax).  Both
   are updated to reflect the new position.  The token itself is
   returned as a pointer into the original buffer at TOK and TOKLEN.
   If a parentheses is the next token, TOK will be set to NULL.
   TOKLEN is checked to be within the bounds.  On error an error code
   is returned and no pointer is not guaranteed to point to
   a meaningful value.  DEPTH should be initialized to 0 and will
   reflect on return the actual depth of the tree. To detect the end
   of the S-expression it is advisable to check DEPTH after a
   successful return. */
gpg_error_t parse_sexp (unsigned char const **buf, size_t *buflen,
                        int *depth, unsigned char const **tok, size_t *toklen);


/*-- tlv-builder.c --*/

tlv_builder_t tlv_builder_new (int use_secure);
void tlv_builder_add_ptr (tlv_builder_t tb, int class, int tag,
                          void *value, size_t valuelen);
void tlv_builder_add_val (tlv_builder_t tb, int class, int tag,
                          const void *value, size_t valuelen);
void tlv_builder_add_tag (tlv_builder_t tb, int class, int tag);
void tlv_builder_add_end (tlv_builder_t tb);
gpg_error_t tlv_builder_finalize (tlv_builder_t tb,
                                  void **r_obj, size_t *r_objlen);

/* Wite a TLV header to MEMBUF.  */
void put_tlv_to_membuf (membuf_t *membuf, int class, int tag,
                        int constructed, size_t length);

/* Count the length of a to be constructed TLV.  */
size_t get_tlv_length (int class, int tag, int constructed, size_t length);


/*-- tlv-parser.c --*/

tlv_parser_t tlv_parser_new (const unsigned char *buffer, size_t bufsize,
                             int verbosity);
void tlv_parser_release (tlv_parser_t tlv);

void _tlv_parser_dump_tag (const char *text, int lno, tlv_parser_t tlv);
void _tlv_parser_dump_state (const char *text, const char *text2,
                             int lno, tlv_parser_t tlv);

int _tlv_parser_peek (tlv_parser_t tlv, int class, int tag);
int _tlv_parser_peek_null (tlv_parser_t tlv);
gpg_error_t _tlv_parser_next (tlv_parser_t tlv, int lno);

unsigned int tlv_parser_level (tlv_parser_t tlv);
size_t tlv_parser_offset (tlv_parser_t tlv);
const char *tlv_parser_lastfunc (tlv_parser_t tlv);
const char *tlv_parser_lasterrstr (tlv_parser_t tlv);
void tlv_parser_set_pending (tlv_parser_t tlv);
size_t tlv_parser_tag_length (tlv_parser_t tlv, int with_header);

void tlv_parser_skip (tlv_parser_t tlv);

gpg_error_t tlv_expect_sequence (tlv_parser_t tlv);
gpg_error_t tlv_expect_context_tag (tlv_parser_t tlv, int *r_tag);
gpg_error_t tlv_expect_set (tlv_parser_t tlv);
gpg_error_t tlv_expect_object (tlv_parser_t tlv, int class, int tag,
                               unsigned char const **r_data,
                               size_t *r_datalen);
gpg_error_t tlv_expect_octet_string (tlv_parser_t tlv, int encapsulates,
                                     unsigned char const **r_data,
                                     size_t *r_datalen);
gpg_error_t tlv_expect_integer (tlv_parser_t tlv, int *r_value);
#ifdef GCRYPT_VERSION
gpg_error_t tlv_expect_mpinteger (tlv_parser_t tlv, int ignore_zero,
                                  gcry_mpi_t *r_value);
#endif
gpg_error_t tlv_expect_object_id (tlv_parser_t tlv,
                                  unsigned char const **r_oid,
                                  size_t *r_oidlen);

/* Easier to use wrapper around parse_ber_header.  */
gpg_error_t tlv_parse_tag (unsigned char const **buffer,
                           size_t *size, struct tag_info *ti);

/* Convenience macro and macros to include the line number.  */
#define tlv_parser_dump_tag(a,b) _tlv_parser_dump_tag ((a),__LINE__,(b))
#define tlv_parser_dump_state(a,b,c) \
                            _tlv_parser_dump_state ((a),(b),__LINE__,(c))
#define tlv_peek(a,b,c) _tlv_parser_peek ((a),(b),(c))
#define tlv_peek_null(a) _tlv_parser_peek_null ((a))
#define tlv_next(a) _tlv_parser_next ((a), __LINE__)



#endif /* SCD_TLV_H */