Release 2.1.2.

[u/mdw/catacomb] / key-pack.c

/* -*-c-*-
 *
 * $Id$
 *
 * Packing and unpacking 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.
 */

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

#include <mLib/dstr.h>

#include "key.h"
#include "key-data.h"

/*----- Generic packing and unpacking -------------------------------------*/

/* --- @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.
 */

int key_pack(key_packdef *kp, key_data **kd, dstr *d)
{
  switch (kp->e & KF_ENCMASK) {

    /* --- Binary and integer keys are easy --- */

    case KENC_BINARY: {
      key_bin *b = kp->p;
      *kd = key_newbinary(kp->e, b->k, b->sz);
      return (0);
    }
    case KENC_MP:
      *kd = key_newmp(kp->e, *(mp **)kp->p);
      return (0);
    case KENC_STRING:
      *kd = key_newstring(kp->e, *(char **)kp->p);
      return (0);
    case KENC_EC:
      *kd = key_newec(kp->e, (ec *)kp->p);
      return (0);

    /* --- Encrypted keys are a little tricky --- *
     *
     * This works rather differently to unpacking.
     */

    case KENC_ENCRYPT: {
      key_data *kkd;
      int err = key_pack(kp->p, &kkd, d);
      if (!err) {
	err = key_plock(kd, kkd, d->buf);
	key_drop(kkd);
      }
      return (err);
    }

    /* --- Structured keys, as ever, are a nuisance --- */

    case KENC_STRUCT: {
      int err;
      key_packstruct *p;
      size_t l = d->len;

      *kd = key_newstruct();
      DPUTC(d, '.');
      for (p = kp->p; p->name; p++) {
	key_data *kkd;
	d->len = l + 1;
	DPUTS(d, p->name);
	if ((err = key_pack(&p->kp, &kkd, d)) != 0) {
	  key_drop(*kd);
	  return (err);
	}
	key_structsteal(*kd, p->name, kkd);
      }
      d->len = l;
      d->buf[l] = 0;
      return (0);
    }
    default:
      abort();
  }
}

/* --- @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.
 */

int key_unpack(key_packdef *kp, key_data *kd, dstr *d)
{
  unsigned e = kp->e & KF_ENCMASK;
  int err;

  /* --- Decrypt the encrypted key --- */

  if ((kd->e & KF_ENCMASK) == KENC_ENCRYPT) {
    if ((err = key_punlock(&kp->kd, kd, d->buf)) != 0)
      goto fail;
    kd = kp->kd;
  }

  /* --- Ensure that the key has the right type --- */

  if ((kd->e & KF_ENCMASK) != e) {
    err = KERR_WRONGTYPE;
    goto fail;
  }

  /* --- Unpack the key --- *
   *
   * Only three possibilities left now.
   */

  switch (e) {

    /* --- Binary and integer keys are easy --- */

    case KENC_BINARY:
      *(key_bin *)kp->p = kd->u.k;
      break;
    case KENC_MP:
      *(mp **)kp->p = kd->u.m;
      break;
    case KENC_STRING:
      *(char **)kp->p = kd->u.p;
      break;
    case KENC_EC:
      *(ec *)kp->p = kd->u.e;
      break;

    /* --- Structured keys take a little care --- */

    case KENC_STRUCT: {
      key_packstruct *p, *q;
      size_t l = d->len;

      /* --- Iterate over the requested subparts --- */

      DPUTC(d, '.');
      for (p = kp->p; p->name; p++) {
	key_data *kkd;

	/* --- Build the name --- */

	d->len = l + 1;
	DPUTS(d, p->name);

	/* --- Find and unpack the subkey --- */

	if ((kkd = key_structfind(kd, p->name)) == 0) {
	  if (!(p->kp.e & KF_OPT)) {
	    err = KERR_NOTFOUND;
	    goto tidy;
	  }
	} else if ((err = key_unpack(&p->kp, kkd, d)) != 0) {
	  p++;
	  goto tidy;
	}
      }

      /* --- Done --- */

      d->len = l;
      d->buf[l] = 0;
      break;

      /* --- Tidy up if something went wrong --- */

    tidy:
      for (q = kp->p; q < p; q++)
	key_unpackdone(&q->kp);
      goto fail;
    }

    default:
      abort();
  }

  return (0);

  /* --- Something went wrong --- */

fail:
  if (kp->kd) {
    key_drop(kp->kd);
    kp->kd = 0;
  }
  return (err);
}

/* --- @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.
 */

void key_unpackdone(key_packdef *kp)
{
  if (kp->kd) {
    key_drop(kp->kd);
    kp->kd = 0;
  }
  if ((kp->e & KF_ENCMASK) == KENC_STRUCT) {
    key_packstruct *p;
    for (p = kp->p; p->name; p++)
      key_unpackdone(&p->kp);
  }
}

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