Muffle GCC warnings in various ways.

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

/* -*-c-*-
 *
 * 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.
 */

#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_KEY_ERROR_H
#  include "key-error.h"
#endif

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

#ifndef CATACOMB_EC_H
#  include "ec.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 */
  unsigned ref;				/* Reference counter */
  union {
    key_bin k;				/* Binary key data */
    mp *m;				/* Multiprecision integer */
    sym_table s;			/* Structured key data */
    char *p;				/* String pointer */
    ec e;				/* Elliptic curve point */
  } u;
} key_data;

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

typedef struct key_subkeyiter { sym_iter i; } key_subkeyiter;

/* --- Packing and unpacking --- */

typedef struct key_packdef {
  unsigned e;				/* Key data encoding type */
  void *p;				/* Pointer to the destination */
  key_data *kd;				/* Key data block */
} key_packdef;

typedef struct key_packstruct {
  char *name;				/* Pointer to name string */
  key_packdef kp;			/* Packing structure */
} key_packstruct;

/* --- 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	= 0x83,			/* 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@) */
  KENC_STRING	= 0x80,			/* ASCII string (@p@) */
  KENC_EC	= 0x81,			/* Elliptic curve point (@e@) */

  /* --- 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_OPT	= 0x20,			/* Optional key (for @key_unpack@) */

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

  KENC_MAX				/* Dummy limit constant */
};

/* --- Key locking return codes --- */

#define KL_OK 0				/* All good */
#define KL_IOERR -1			/* I/O problem (e.g., getting pp) */
#define KL_KEYERR -2			/* Wrong key supplied */
#define KL_DATAERR -3			/* Data format error */

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

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

/* --- Matching aginst key selection --- *
 *
 * GCC will warn about constant addresses in this test, which is rather
 * unfortunate.  Muffle the warning.  This is rather hideous because of the
 * way GCC's parser handles pragmata.
 */

#if __GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
#  define KEY_MATCH_MUFFLE_WARNING(x) __extension__ ({			\
	_Pragma("GCC diagnostic push")					\
	_Pragma("GCC diagnostic ignored \"-Waddress\"")			\
	(x);								\
	_Pragma("GCC diagnostic pop")					\
   })
#else
#  define KEY_MATCH_MUFFLE_WARNING(x) (x)
#endif

#define KEY_MATCH(kd, kf)						\
  (KEY_MATCH_MUFFLE_WARNING(!(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_newraw@ --- *
 *
 * Arguments:	@unsigned e@ = encoding type to set
 *
 * Returns:	New key block, not filled in.
 */

extern key_data *key_newraw(unsigned /*e*/);

/* --- @key_newbinary@ --- *
 *
 * Arguments:	@unsigned e@ = other encoding flags
 *		@const void *p@ = pointer to key data
 *		@size_t sz@ = size of the key data
 *
 * Returns:	New key data object.
 */

extern key_data *key_newbinary(unsigned /*e*/,
			       const void */*p*/, size_t /*sz*/);

/* --- @key_newencrypted@ --- *
 *
 * Arguments:	@unsigned e@ = other encoding flags
 *		@const void *p@ = pointer to key data
 *		@size_t sz@ = size of the key data
 *
 * Returns:	New key data object.
 */

extern key_data *key_newencrypted(unsigned /*e*/,
				  const void */*p*/, size_t /*sz*/);

/* --- @key_newmp@ --- *
 *
 * Arguments:	@unsigned e@ = other encoding flags
 *		@mp *m@ = pointer to the value to set
 *
 * Returns:	New key data object.
 */

extern key_data *key_newmp(unsigned /*e*/, mp */*m*/);

/* --- @key_newstring@ --- *
 *
 * Arguments:	@unsigned e@ = other encoding flags
 *		@const char *p@ = pointer to the value to set
 *
 * Returns:	New key data object.
 */

extern key_data *key_newstring(unsigned /*e*/, const char */*p*/);

/* --- @key_newec@ --- *
 *
 * Arguments:	@unsigned e@ = other encoding flags
 *		@const ec *pt@ = pointer to the value to set
 *
 * Returns:	New key data object.
 */

extern key_data *key_newec(unsigned /*e*/, const ec */*pt*/);

/* --- @key_newstruct@ --- *
 *
 * Arguments:	---
 *
 * Returns:	New key data object.
 */

extern key_data *key_newstruct(void);

/* --- @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_mksubkeyiter@ --- *
 *
 * Arguments:	@key_subkeyiter *i@ = pointer to iterator block
 *		@key_data *k@ = pointer to key data block
 *
 * Returns:	---
 *
 * Use:		Initializes a subkey iterator.
 */

extern void key_mksubkeyiter(key_subkeyiter */*i*/, key_data */*k*/);

/* --- @key_nextsubkey@ --- *
 *
 * Arguments:	@key_structiter *i@ = pointer to iterator block
 *		@const char **tag@ = where to put the tag pointer, or null
 *		@key_data **kd@ = where to put the key data pointer, or null
 *
 * Returns:	Nonzero if there was another item, zero if we hit the
 *		end-stop.
 *
 * Use:		Collects the next subkey of a structured key.
 */

extern int key_nextsubkey(key_subkeyiter */*i*/,
			  const char **/*tag*/, key_data **/*kd*/);

/* --- @key_structset@, @key_structsteal@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data block
 *		@const char *tag@ = pointer to tag string
 *		@key_data *kd@ = new key data to store
 *
 * Returns:	---
 *
 * Use:		Creates a new subkey.  Stealing doesn't affect @kd@'s
 *		refcount.  If @kd@ is null, the subkey is deleted.
 */

extern void key_structset(key_data */*k*/,
			  const char */*tag*/, key_data */*kd*/);
extern void key_structsteal(key_data */*k*/,
			    const char */*tag*/, key_data */*kd*/);

/* --- @key_split@ --- *
 *
 * Arguments:	@key_data **kk@ = address of pointer to key data block
 *
 * Returns:	---
 *
 * Use:		Replaces @*kk@ with a pointer to the same key data, but with
 *		just one reference.
 */

extern void key_split(key_data **/*kk*/);

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

/* --- @key_incref@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data
 *
 * Returns:	---
 *
 * Use:		Increments the refcount on a key data block.
 */

#define KEY_INCREF(k) ((k)->ref++)
extern void key_incref(key_data */*k*/);

/* --- @key_destroy@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data to destroy
 *
 * Returns:	---
 *
 * Use:		Destroys a block of key data, regardless of reference count.
 *		Don't use this unless you know what you're doing.
 */

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

/* --- @key_drop@ --- *
 *
 * Arguments:	@key_data *k@ = pointer to key data to destroy
 *
 * Returns:	---
 *
 * Use:		Drops a reference to key data, destroying it if necessary.
 */

#define KEY_DROP(k) do {						\
  key_data *_k = k;							\
  _k->ref--;								\
  if (_k->ref == 0)							\
    key_destroy(_k);							\
} while (0)

extern void key_drop(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_copydata@ --- *
 *
 * Arguments:	@key_data *k@ = key data to copy
 *		@const key_filter *kf@ = pointer to filter block
 *
 * Returns:	Pointer to a copy of the data, or null if the root subkey
 *		didn't match the filter.
 *
 * Use:		Copies a chunk of key data.  Subkeys, whether they're
 *		structured or leaves, which don't match the filter aren't
 *		copied.  The copy may or may not have structure in common
 *		with the original.
 */

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

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

/* --- @key_read@ --- *
 *
 * Arguments:	@const char *p@ = pointer to textual key representation
 *		@char **pp@ = where to store the end pointer
 *
 * Returns:	The newly-read key data, or null if it failed.
 *
 * Use:		Parses a textual key description.
 */

extern key_data *key_read(const char */*p*/, 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
 *
 * Returns:	The newly-read key data, or null if it failed.
 *
 * Use:		Decodes a binary representation of a key.
 */

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

/* --- @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*/);

/*----- Packing and unpacking keys ----------------------------------------*/

/* --- @key_pack@ --- *
 *
 * Arguments:	@key_packdef *kp@ = pointer to packing structure
 *		@key_data **kd@ = where to put the key data pointer
 *		@dstr *d@ = pointer to tag string for the key data
 *
 * Returns:	Error code, or zero.
 *
 * Use:		Packs a key from a data structure.
 */

extern int key_pack(key_packdef */*kp*/, key_data **/*kd*/, dstr */*d*/);

/* --- @key_unpack@ --- *
 *
 * Arguments:	@key_packdef *kp@ = pointer to packing structure
 *		@key_data *kd@ = pointer to source key data
 *		@dstr *d@ = pointer to tag string for the key data
 *
 * Returns:	Error code, or zero.
 *
 * Use:		Unpacks a key into an appropriate data structure.
 */

extern int key_unpack(key_packdef */*kp*/, key_data */*kd*/, dstr */*d*/);

/* --- @key_unpackdone@ --- *
 *
 * Arguments:	@key_packdef *kp@ = pointer to packing definition
 *
 * Returns:	---
 *
 * Use:		Frees the key components contained within a packing
 *		definition, created during key unpacking.
 */

extern void key_unpackdone(key_packdef */*kp*/);

/*----- Key encryption ----------------------------------------------------*/

/* --- @key_lock@ --- *
 *
 * Arguments:	@key_data **kt@ = where to store the destination pointer
 *		@key_data *k@ = source key data block or null to use @*kt@
 *		@const void *e@ = secret to encrypt key with
 *		@size_t esz@ = size of the secret
 *
 * Returns:	---
 *
 * Use:		Encrypts a key data block using a secret.
 */

extern void key_lock(key_data **/*kt*/, key_data */*k*/,
		     const void */*e*/, size_t /*esz*/);

/* --- @key_unlock@ --- *
 *
 * Arguments:	@key_data **kt@ = where to store the destination pointer
 *		@key_data *k@ = source key data block or null to use @*kt@
 *		@const void *e@ = secret to decrypt the block with
 *		@size_t esz@ = size of the secret
 *
 * Returns:	Zero for success, or a @KERR_@ error code.
 *
 * Use:		Unlocks a key using a secret.
 */

extern int key_unlock(key_data **/*kt*/, key_data */*k*/,
		      const void */*e*/, size_t /*esz*/);

/* --- @key_plock@ --- *
 *
 * Arguments:	@key_data **kt@ = where to store the destination pointer
 *		@key_data *k@ = source key data block or null to use @*kt@
 *		@const char *tag@ = tag to use for passphrase
 *
 * Returns:	Zero if successful, a @KERR@ error code on failure.
 *
 * Use:		Locks a key by encrypting it with a passphrase.
 */

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

/* --- @key_punlock@ --- *
 *
 * Arguments:	@key_data **kt@ = where to store the destination pointer
 *		@key_data *k@ = source key data block or null to use @*kt@
 *		@const char *tag@ = tag to use for passphrase
 *
 * Returns:	Zero if successful, a @KERR@ error code on failure.
 *
 * Use:		Unlocks a passphrase-locked key.
 */

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

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

#ifdef __cplusplus
  }
#endif

#endif