Table for driving key data extraction.

[u/mdw/catacomb] / key-data.h

/* -*-c-*-
 *
 * $Id: key-data.h,v 1.1 2000/02/12 18:21:23 mdw Exp $
 *
 * Manipulating key data
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb 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 Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: key-data.h,v $
 * Revision 1.1  2000/02/12 18:21:23  mdw
 * Overhaul of key management (again).
 *
 */

#ifndef CATACOMB_KEY_DATA_H
#define CATACOMB_KEY_DATA_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <stddef.h>

#include <mLib/bits.h>
#include <mLib/dstr.h>
#include <mLib/sym.h>

#ifndef CATACOMB_MP_H
#  include "mp.h"
#endif

/*----- Data structures ---------------------------------------------------*/

/* --- Key binary data --- */

typedef struct key_bin {
  octet *k;				/* Pointer to key data */
  size_t sz;				/* Size of the key data (in bytes) */
} key_bin;

/* --- Key data structure --- */

typedef struct key_data {
  unsigned e;				/* Encoding type for key data */
  union {
    key_bin k;				/* Binary key data */
    mp *m;				/* Multiprecision integer */
    sym_table s;			/* Structured key data */
  } u;
} key_data;

typedef struct key_struct {
  sym_base _b;
  key_data k;
} key_struct;

/* --- Key binary encoding --- *
 *
 * The binary encoding consists of a header containing a 16-bit encoding type
 * and a 16-bit length, followed immediately by the key data, followed by
 * between zero and three zero bytes to make the total length a multiple of
 * four.  The format of the following data depends on the encoding type:
 *
 * @KENC_BINARY@	Binary data.
 *
 * @KENC_MP@		Octet array interpreted in big-endian byte order.
 *
 * @KENC_STRUCT@	An array of pairs, each containing a string (8-bit
 *			length followed by data and zero-padding to 4-byte
 *			boundary) and key binary encodings.
 *
 * @KENC_ENCRYPT@	Binary data, format
 */

/* --- Key encoding methods and other flags--- */

enum {

  /* --- Bottom two bits are the encoding type --- */

  KF_ENCMASK	= 0x03,			/* Encoding mask */
  KENC_BINARY	= 0x00,			/* Plain binary key (@k@) */
  KENC_MP	= 0x01,			/* Multiprecision integer (@i@) */
  KENC_STRUCT	= 0x02,			/* Structured key data (@s@) */
  KENC_ENCRYPT	= 0x03,			/* Encrypted key type (@k@) */

  /* --- Key category bits --- */

  KF_CATMASK	= 0x0c,			/* Category mask */
  KCAT_SYMM	= 0x00,			/* Symmetric encryption key */
  KCAT_PRIV	= 0x04,			/* Private (asymmetric) key */
  KCAT_PUB	= 0x08,			/* Public (asymmetric) key */
  KCAT_SHARE	= 0x0c,			/* Shared (asymmetric) key */
  KF_NONSECRET	= 0x08,			/* Bit flag for non-secret keys */

  /* --- Other flags --- */

  KF_BURN	= 0x10,			/* Burn key after use */
  KF_TEMP	= 0x20,			/* Temporary copy flag */

  /* --- Tag end --- */

  KENC_MAX				/* Dummy limit constant */
};

/* --- Key flag filtering --- */

typedef struct key_filter {
  unsigned f;
  unsigned m;
} key_filter;

/* --- Matching aginst key selection --- */

#define KEY_MATCH(kd, kf)						\
  (!(kf) ||								\
   ((kd)->e & KF_ENCMASK) == KENC_STRUCT ||				\
   ((kd)->e & (kf)->m) == (kf)->f)

/*----- Key flags and filtering -------------------------------------------*/

/* --- @key_readflags@ --- *
 *
 * Arguments:	@const char *p@ = pointer to string to read
 *		@char **pp@ = where to store the end pointer
 *		@unsigned *ff@ = where to store the flags
 *		@unsigned *mm@ = where to store the mask
 *
 * Returns:	Zero if all went well, nonzero if there was an error.
 *
 * Use:		Reads a flag string.
 */

extern int key_readflags(const char */*p*/, char **/*pp*/,
			 unsigned */*ff*/, unsigned */*mm*/);

/* --- @key_writeflags@ --- *
 *
 * Arguments:	@unsigned f@ = flags to write
 *		@dstr *d@ = pointer to destination string
 *
 * Returns:	---
 *
 * Use:		Emits a flags word as a string representation.
 */

extern void key_writeflags(unsigned /*f*/, dstr */*d*/);

/* --- @key_match@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@const key_filter *kf@ = pointer to filter block
 *
 * Returns:	Nonzero if the key matches the filter.
 *
 * Use:		Checks whether a key matches a filter.
 */

extern int key_match(key_data */*k*/, const key_filter */*kf*/);

/*----- Setting new key data ----------------------------------------------*/

/* --- @key_binary@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@const void *p@ = pointer to key data
 *		@size_t sz@ = size of the key data
 *
 * Returns:	---
 *
 * Use:		Sets a binary key in a key data block.
 */

extern void key_binary(key_data */*k*/, const void */*p*/, size_t /*sz*/);

/* --- @key_encrypted@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@const void *p@ = pointer to key data
 *		@size_t sz@ = size of the key data
 *
 * Returns:	---
 *
 * Use:		Sets an encrypted key in a key data block.
 */

extern void key_encrypted(key_data */*k*/, const void */*p*/, size_t /*sz*/);

/* --- @key_mp@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@mp *m@ = pointer to the value to set
 *
 * Returns:	---
 *
 * Use:		Sets a multiprecision integer key in a key block.
 */

extern void key_mp(key_data */*k*/, mp */*m*/);

/* --- @key_structure@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *
 * Returns:	---
 *
 * Use:		Initializes a structured key type.
 */

extern void key_structure(key_data */*k*/);

/* --- @key_structfind@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@const char *tag@ = pointer to tag string
 *
 * Returns:	Pointer to key data block, or null.
 *
 * Use:		Looks up the tag in a structured key.
 */

extern key_data *key_structfind(key_data */*k*/, const char */*tag*/);

/* --- @key_structcreate@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@const char *tag@ = pointer to tag string
 *
 * Returns:	Pointer to newly created key data.
 *
 * Use:		Creates a new uninitialized subkey.
 */

extern key_data *key_structcreate(key_data */*k*/, const char */*tag*/);

/*----- Miscellaneous operations ------------------------------------------*/

/* --- @key_destroy@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data to destroy
 *
 * Returns:	---
 *
 * Use:		Destroys a lump of key data.
 */

extern void key_destroy(key_data */*k*/);

/* --- @key_do@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@const key_filter *kf@ = pointer to filter block
 *		@dstr *d@ = pointer to base string
 *		@int (*func)(key_data *kd, dstr *d, void *p@ = function
 *		@void *p@ = argument to function
 *
 * Returns:	Nonzero return code from function, or zero.
 *
 * Use:		Runs a function over all the leaves of a key. 
 */

extern int key_do(key_data */*k*/, const key_filter */*kf*/, dstr */*d*/,
		  int (*/*func*/)(key_data */*kd*/,
				  dstr */*d*/, void */*p*/),
		  void */*p*/);

/* --- @key_copy@ --- *
 *
 * Arguments:	@key_data *kd@ = pointer to destination data block
 *		@key_data *k@ = pointer to source data block
 *		@const key_filter *kf@ = pointer to filter block
 *
 * Returns:	Nonzero if an item was actually copied.
 *
 * Use:		Copies a chunk of key data from one place to another.
 */

extern int key_copy(key_data */*kd*/, key_data */*k*/,
		    const key_filter */*kf*/);

/*----- Textual encoding --------------------------------------------------*/

/* --- @key_read@ --- *
 *
 * Arguments:	@const char *p@ = pointer to textual key representation
 *		@key_data *k@ = pointer to output block for key data
 *		@char **pp@ = where to store the end pointer
 *
 * Returns:	Zero if all went well, nonzero if there was a problem.
 *
 * Use:		Parses a textual key description.
 */

extern int key_read(const char */*p*/, key_data */*k*/, char **/*pp*/);

/* --- @key_write@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data
 *		@dstr *d@ = destination string to write on
 *		@const key_filter *kf@ = pointer to key selection block
 *
 * Returns:	Nonzero if any items were actually written.
 *
 * Use:		Writes a key in a textual encoding.
 */

extern int key_write(key_data */*k*/, dstr */*d*/,
		      const key_filter */*kf*/);

/*----- Key binary encoding -----------------------------------------------*/

/* --- @key_decode@ --- *
 *
 * Arguments:	@const void *p@ = pointer to buffer to read
 *		@size_t sz@ = size of the buffer
 *		@key_data *k@ = pointer to key data block to write to
 *
 * Returns:	Zero if everything worked, nonzero otherwise.
 *
 * Use:		Decodes a binary representation of a key.
 */

extern int key_decode(const void */*p*/, size_t /*sz*/, key_data */*k*/);

/* --- @key_encode@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@dstr *d@ = pointer to destination string
 *		@const key_filter *kf@ = pointer to key selection block
 *
 * Returns:	Nonzero if any items were actually written.
 *
 * Use:		Encodes a key block as binary data.
 */

extern int key_encode(key_data */*k*/, dstr */*d*/,
		      const key_filter */*kf*/);

/*----- Passphrase encryption ---------------------------------------------*/

/* --- @key_plock@ --- *
 *
 * Arguments:	@const char *tag@ = tag to use for passphrase
 *		@key_data *k@ = source key data block
 *		@key_data *kt@ = target key data block
 *
 * Returns:	Zero if successful, nonzero if there was a problem.
 *
 * Use:		Locks a key by encrypting it with a passphrase.
 */

extern int key_plock(const char */*tag*/, key_data */*k*/, key_data */*kt*/);

/* --- @key_punlock@ --- *
 *
 * Arguments:	@const char *tag@ = tag to use for passphrase
 *		@key_data *k@ = source key data block
 *		@key_data *kt@ = target key data block
 *
 * Returns:	Zero if it worked, nonzero if it didn't.
 *
 * Use:		Unlocks a passphrase-locked key.
 */

extern int key_punlock(const char */*tag*/,
		       key_data */*k*/, key_data */*kt*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif